Pivotal role for S-nitrosylation of DNA methyltransferase 3B in epigenetic regulation of tumorigenesis.

DNA methyltransferases (DNMTs) catalyze methylation at the C5 position of cytosine with S-adenosyl-L-methionine. Methylation regulates gene expression, serving a variety of physiological and pathophysiological roles. The chemical mechanisms regulating DNMT enzymatic activity, however, are not fully elucidated. Here, we show that protein S-nitrosylation of a cysteine residue in DNMT3B attenuates DNMT3B enzymatic activity and consequent aberrant upregulation of gene expression. These genes include Cyclin D2 (Ccnd2), which is required for neoplastic cell proliferation in some tumor types. In cell-based and in vivo cancer models, only DNMT3B enzymatic activity, and not DNMT1 or DNMT3A, affects Ccnd2 expression. Using structure-based virtual screening, we discovered chemical compounds that specifically inhibit S-nitrosylation without directly affecting DNMT3B enzymatic activity. The lead compound, designated DBIC, inhibits S-nitrosylation of DNMT3B at low concentrations (IC

≤ 100 nM). Treatment with DBIC prevents nitric oxide (NO)-induced conversion of human colonic adenoma to adenocarcinoma in vitro. Additionally, in vivo treatment with DBIC strongly attenuates tumor development in a mouse model of carcinogenesis triggered by inflammation-induced generation of NO. Our results demonstrate that de novo DNA methylation mediated by DNMT3B is regulated by NO, and DBIC protects against tumor formation by preventing aberrant S-nitrosylation of DNMT3B.


Blue light induces apoptosis and autophagy by promoting ROS-mediated mitochondrial dysfunction in synovial sarcoma.

Taken together, our results revealed that BL induced apoptosis via the ROS-mitochondrial signaling pathway, and autophagy was activated in response to the production of ROS, which protected SS cells from apoptosis. Therefore, BL is a promising candidate for the development of an antitumor therapeutic strategy targeting SS.


Fine-tuning of β-catenin in mouse thymic epithelial cells is required for postnatal T-cell development

In the thymus, the thymic epithelium provides a microenvironment essential for the development of functionally competent and self-tolerant T cells. Previous findings showed that modulation of Wnt/β-catenin signaling in mouse thymic epithelial cells (TECs) disrupts embryonic thymus organogenesis. However, the role of β-catenin in TECs for postnatal T-cell development remains to be elucidated. Here, we analyzed gain-of-function (GOF) and loss-of-function (LOF) of β-catenin highly specific in mouse TECs. We found that GOF of β-catenin in TECs results in severe thymic dysplasia and T-cell deficiency beginning from the embryonic period. By contrast, LOF of β-catenin in TECs reduces the number of cortical TECs and thymocytes modestly and only postnatally. These results indicate that fine-tuning of β-catenin expression within a permissive range is required for TECs to generate an optimal microenvironment to support postnatal T-cell development.


FZD10-targeted α-radioimmunotherapy with 225 Ac-labeled OTSA101 achieves complete remission in a synovial sarcoma model

Ac-labeled OTSA101 is a promising therapeutic option for synovial sarcoma.

Synovial sarcomas are rare tumors arising in adolescents and young adults. The prognosis for advanced disease is poor, with an overall survival of 12-18 months. Frizzled homolog 10 (FZD10) is overexpressed in most synovial sarcomas, making it a promising therapeutic target. The results of a phase 1 trial of β-radioimmunotherapy (RIT) with the


The survival and proliferation of osteosarcoma cells are dependent on the mitochondrial BIG3-PHB2 complex formation.

Previous studies reported the critical role of the brefeldin A-inhibited guanine nucleotide exchange protein 3-prohibitin 2 (BIG3-PHB2) complex in modulating estrogen signaling activation in breast cancer cells, yet its pathophysiological roles in osteosarcoma (OS) cells remain elusive. Here, we report a novel function of BIG3-PHB2 in OS malignancy. BIG3-PHB2 complexes were localized mainly in mitochondria in OS cells, unlike in estrogen-dependent breast cancer cells. Depletion of endogenous BIG3 expression by small interfering RNA (siRNA) treatment led to significant inhibition of OS cell growth. Disruption of BIG3-PHB2 complex formation by treatment with specific peptide inhibitor also resulted in significant dose-dependent suppression of OS cell growth, migration, and invasion resulting from G2/M-phase arrest and in PARP cleavage, ultimately leading to PARP-1/apoptosis-inducing factor (AIF) pathway activation-dependent apoptosis in OS cells. Subsequent proteomic and bioinformatic pathway analyses revealed that disruption of the BIG3-PHB2 complex might lead to downregulation of inner mitochondrial membrane protein complex activity. Our findings indicate that the mitochondrial BIG3-PHB2 complex might regulate PARP-1/AIF pathway-dependent apoptosis during OS cell proliferation and progression and that disruption of this complex may be a promising therapeutic strategy for OS.


Functional genomics for breast cancer drug target discovery.

Breast cancer is a heterogeneous disease that develops through a multistep process via the accumulation of genetic/epigenetic alterations in various cancer-related genes. Current treatment options for breast cancer patients include surgery, radiotherapy, and chemotherapy including conventional cytotoxic and molecular-targeted anticancer drugs for each intrinsic subtype, such as endocrine therapy and antihuman epidermal growth factor receptor 2 (HER2) therapy. However, these therapies often fail to prevent recurrence and metastasis due to resistance. Overall, understanding the molecular mechanisms of breast carcinogenesis and progression will help to establish therapeutic modalities to improve treatment. The recent development of comprehensive omics technologies has led to the discovery of driver genes, including oncogenes and tumor-suppressor genes, contributing to the development of molecular-targeted anticancer drugs. Here, we review the development of anticancer drugs targeting cancer-specific functional therapeutic targets, namely, MELK (maternal embryonic leucine zipper kinase), TOPK (T-lymphokine-activated killer cell-originated protein kinase), and BIG3 (brefeldin A-inhibited guanine nucleotide-exchange protein 3), as identified through comprehensive breast cancer transcriptomics.


ERAD components Derlin-1 and Derlin-2 are essential for postnatal brain development and motor function.

and surprisingly also inhibited sterol regulatory element binding protein 2 (SREBP-2)-mediated brain cholesterol biosynthesis. In addition, reduced neurite outgrowth due to Derlin-1 deficiency was rescued by SREBP-2 pathway activation. Overall, our findings demonstrate that Derlins sustain brain cholesterol biosynthesis, which is essential for appropriate postnatal brain development and function.


Large-scale genome-wide association study in a Japanese population identifies novel susceptibility loci across different diseases.

). East Asian-specific missense variants were identified as candidate causal variants for three novel loci, and we successfully replicated two of them by analyzing independent Japanese cohorts; p.R220W of ATG16L2 (associated with coronary artery disease) and p.V326A of POT1 (associated with lung cancer). We further investigated enrichment of heritability within 2,868 annotations of genome-wide transcription factor occupancy, and identified 378 significant enrichments across nine diseases (false discovery rate < 0.05) (for example, NKX3-1 for prostate cancer). This large-scale GWAS in a Japanese population provides insights into the etiology of complex diseases and highlights the importance of performing GWAS in non-European populations.


Significant association between high serum CCL5 levels and better disease-free survival of patients with early breast cancer.

Analysis of anticancer immunity aids in assessing the prognosis of patients with breast cancer. From 250 operated breast cancers, we focused on serum levels of C-C motif chemokine ligand 5 (CCL5), which is involved in cancer immune reactions. Serum levels of CCL5 were measured using a cytometric bead-based immunoassay kit and CCL5 expression in cancer cells was determined using immunohistochemical staining. In addition, mRNA in cancer and stromal cells was analyzed by microdissection and comparison with the public dataset. Disease-free survival (DFS) of patients with high CCL5 levels (cut-off, 13.87 ng/mL; n = 192) was significantly better than those with low CCL5 levels (n = 58; hazard ratio, 0.20; 95% confidence interval, 0.10-0.39; P < .0001). An improved overall survival was observed in patients with high CCL5 levels compared to those with low CCL5 levels (P = .024). On the contrary, high immunohistochemical expression of CCL5 in cancer cells was significantly associated with decreased DFS. As serum CCL5 levels did not correlate with CCL5 expression in cancer cells and the relative expression of mRNA CCL5 was elevated in stromal cells in relation to cancer cells, serum CCL5 might be derived not from cancer cells, but from stromal cells. Expression of CCL5 in serum, but not in cancer cells, might contribute to improved patient prognosis mediating through not only immune reaction, but through other mechanisms. Determination of circulating CCL5 levels could be useful for predicting patient prognosis.


The GALNT6‑LGALS3BP axis promotes breast cancer cell growth.

Polypeptide N‑acetylgalactosaminyltransferase 6 (GALNT6), which is involved in the initiation of O‑glycosylation, has been reported to play crucial roles in mammary carcinogenesis through binding to several substrates; however, its biological roles in mediating growth‑promoting effects remain unknown. The present study demonstrated a crucial pathophysiological role of GALNT6 through its O‑glycosylation of lectin galactoside‑binding soluble 3 binding protein (LGALS3BP), a secreted growth‑promoting glycoprotein, in breast cancer growth. The Cancer Genome Atlas data analysis revealed that high expression levels of GALNT6 were significantly associated with poor prognosis of breast cancer. GALNT6 O‑glycosylated LGALS3BP in breast cancer cells, whereas knockdown of GALNT6 by siRNA led to the inhibition of both the O‑glycosylation and secretion of LGALS3BP, resulting in the suppression of breast cancer cell growth. Notably, LGALS3BP is potentially O‑glycosylated at three sites (T556, T571 and S582) by GALNT6, thereby promoting autocrine cell growth, whereas the expression of LGALS3BP with three Ala substitutions (T556A, T571A and S582A) in cells drastically reduced GALNT6‑dependent LGALS3BP O‑glycosylation and secretion, resulting in suppression of autocrine growth‑promoting effect. The findings of the present study suggest that the GALNT6‑LGALS3BP axis is crucial for breast cancer cell proliferation and may be a therapeutic target and biomarker for mammary tumors.


Trans-omics Impact of Thymoproteasome in Cortical Thymic Epithelial Cells.


Identification of two novel breast cancer loci through large-scale genome-wide association study in the Japanese population.

with nine previously reported loci and two novel loci that include rs9862599 on 3q13.11 (ALCAM) and rs75286142 on 21q22.12 (CLIC6-RUNX1). Validation study was carried out with 981 breast cancer cases and 1,394 controls from the Aichi Cancer Center. Pathway analyses of GWAS signals identified association of dopamine receptor medicated signaling and protein amino acid deacetylation with breast cancer. Weighted genetic risk score showed that individuals who were categorized in the highest risk group are approximately 3.7 times more likely to develop breast cancer compared to individuals in the lowest risk group. This well-powered GWAS is a representative study to identify SNPs that are associated with breast cancer in the Japanese population.

Genome-wide association studies (GWAS) have successfully identified about 70 genomic loci associated with breast cancer. Owing to the complexity of linkage disequilibrium and environmental exposures in different populations, it is essential to perform regional GWAS for better risk prediction. This study aimed to investigate the genetic architecture and to assess common genetic risk model of breast cancer with 6,669 breast cancer patients and 21,930 female controls in the Japanese population. This GWAS identified 11 genomic loci that surpass genome-wide significance threshold of P < 5.0 × 10


High Serum Levels of Interleukin-18 Are Associated With Worse Outcomes in Patients With Breast Cancer.

IL-18 levels may be useful for predicting the prognosis of patients who have received surgical treatment for breast cancer.


Biophysical characterization of the breast cancer-related BIG3-PHB2 interaction: Effect of non-conserved loop region of BIG3 on the structure and the interaction.

Brefeldin A-inhibited guanine nucleotide-exchange protein 3 (BIG3) interacts with and inhibits the tumor suppressor function of prohibitin-2 (PHB2), and recent in vivo studies have demonstrated that the BIG3-PHB2 interaction is a promising target for breast cancer therapy. However, little biophysical characterization on BIG3 and its interaction with PHB2 has been reported. Here we compared the calculated 8-class secondary structure of the N-terminal domains of BIG family proteins and identified a loop region unique to BIG3. Our biophysical characterization demonstrated that this loop region significantly affects the colloidal and thermodynamic stability of BIG3 and the thermodynamic and kinetic profile of its interaction with PHB2. These results establish a model for the BIG3-PHB2 interaction and an entry for drug discovery for breast cancer.

Biochemical and Biophysical Research Communications


Germline pathogenic variants of 11 breast cancer genes in 7,051 Japanese patients and 11,241 controls.

Pathogenic variants in highly penetrant genes are useful for the diagnosis, therapy, and surveillance for hereditary breast cancer. Large-scale studies are needed to inform future testing and variant classification processes in Japanese. We performed a case-control association study for variants in coding regions of 11 hereditary breast cancer genes in 7051 unselected breast cancer patients and 11,241 female controls of Japanese ancestry. Here, we identify 244 germline pathogenic variants. Pathogenic variants are found in 5.7% of patients, ranging from 15% in women diagnosed <40 years to 3.2% in patients 80 years, with BRCA1/2, explaining two-thirds of pathogenic variants identified at all ages. BRCA1/2, PALB2, and TP53 are significant causative genes. Patients with pathogenic variants in BRCA1/2 or PTEN have significantly younger age at diagnosis. In conclusion, BRCA1/2, PALB2, and TP53 are the major hereditary breast cancer genes, irrespective of age at diagnosis, in Japanese women.


Critical Role of Estrogen Receptor Alpha O-Glycosylation by N-Acetylgalactosaminyltransferase 6 (GALNT6) in Its Nuclear Localization in Breast Cancer Cells.

Alteration of protein O-glycosylation in various human cancers including breast cancer is well known, but molecular roles of their aberrant glycosylations on cancer have not been fully understood. We previously reported critical roles of polypeptide N-acetylgalactosaminyltransferase 6 (GALNT6 or GalNAc-T6) that was upregulated in a great majority of breast cancer tissues. Here we further report O-glycosylation of estrogen receptor alpha (ER-) by GALNT6 and the significant role of its nuclear localization in breast cancer cells. Knockdown of GALNT6 expression in two breast cancer cell lines, T47D and MCF7, in which both ER- and GALNT6 were highly expressed, by small interfering RNA could significantly attenuate expression of ER-. Immunocytochemical analysis clearly demonstrated the drastic decrease of ER- protein in the nucleus of these cancer cells. Accordingly, the downstream genes of the ER- pathway such as MYC, CCND1, and CTSD were significantly downregulated. We confirmed GALNT6-dependent ER- O-glycosylation and identified O-glycosylation of S573 in an F domain of ER- by GALNT6 through LC-MS/MS analysis. We also obtained evidences showing that the glycosylation of ER- at S573 by GALNT6 is essential for protein stability and nuclear localization of ER- in breast cancer cells. Furthermore, we designed cell membrane-permeable peptides including the O-glycosylation site and found a significant decrease of the cell viability of breast cancer cells by treatment of these peptides in a GALNT6 expression-dependent manner. Our study suggests that targeting the GALNT6 enzymatic activity as well as the GALNT6/ER- interaction could be a promising therapeutic approach to ER--positive breast cancer patients.


A prospective study to examine the accuracies and efficacies of prediction systems for response to neoadjuvant chemotherapy for muscle invasive bladder cancer.

The present study established systems to predict the chemo-sensitivity of muscle invasive bladder cancer (MIBC) for neoadjuvant chemotherapy (NAC) with methotrexate, vinblastine, doxorubicin plus cisplatin (M-VAC) and carboplatin plus gemcitabine (CaG) by analyzing microarray data. The primary aim of the study was to investigate whether the clinical response would increase by combining these prediction systems. Treatment of each MIBC case was allocated into M-VAC NAC, CaG NAC, surgery, or radiation therapy groups by their prediction score (PS), which was calculated using the designed chemo-sensitivity prediction system. The therapeutic effect of the present study was compared with the results of historical controls (n=76 patients) whose treatments were not allocated using the chemo-sensitivity prediction system. In addition, the overall survival between the predicted to be responder (positive PS) group and predicted to be non-responder (negative PS) group was investigated in the present study. Of the 33 patients with MIBC, 25 cases were positive PS and 8 were negative PS. Among the 25 positive PS cases, 7 were allocated to receive M-VAC NAC and 18 were allocated to receive CaG NAC according to the results of the prediction systems. Of the 8 negative PS cases, 3 received CaG NAC, 1 received surgery without NAC and 4 received radiation therapy. The total clinical response to NAC was 88.0% (22/25), which was significantly increased compared with the historical controls [56.6% (43/76) P=0.0041]. Overall survival of the positive PS group in the study was significantly increased compared with the negative PS group (P=0.027). In conclusion, the combination of the two prediction systems may increase the treatment efficacy for patients with MIBC by proposing the optimal NAC regimen. In addition, the positive PS group would have a better prognosis compared with the negative PS group. These results suggest that the two prediction systems may lead to the achievement of 'precision medicine'.


α-particle therapy for synovial sarcoma in the mouse using an astatine-211-labeled antibody against frizzled homolog 10.

At-OTSA101 is a potential new therapeutic option for SS.


A first-in-human study investigating biodistribution, safety and recommended dose of a new radiolabeled MAb targeting FZD10 in metastatic synovial sarcoma patients.

The study was registered on the NCT01469975 website with a registration code NCT01469975 on November the third, 2011.

Y-OTSA-101 treatment. The recommended activity for further clinical investigations is 1110 MBq of


A DDX31/mutant-p53/EGFR axis promotes multistep progression of muscle invasive bladder cancer

The p53 and EGFR pathways are frequently altered in bladder cancer, yet their contributions to its progression remain elusive. Here we report that DEAD box polypeptide 31 (DDX31) plays a critical role in the multistep progression of muscle-invasive bladder cancer (MIBC) through its sequential interactions with mutant p53 (mutp53) and EGFR. In early MIBC cells, nuclear DDX31-bound mutp53/SP1 enhanced mutp53 transcriptional activation, leading to migration and invasion of MIBC. Cytoplasmic DDX31 also bound EGFR and phospho-nucleolin in advanced MIBC, leading to EGFR-Akt signaling activation. High expression of both cytoplasmic DDX31 and p53 proteins correlated with poor prognosis in patients with MIBC, and blocking the DDX31/NCL interaction resulted in downregulation of EGFR/Akt signaling, eliciting an antitumor effect against bladder cancer. These findings reveal that DDX31 cooperates with mutp53 and EGFR to promote progression of MIBC, and inhibition of DDX31/NCL formation may lead to potential treatment strategies for advanced MIBC. DDX31 cooperates with mutp53 and EGFR to promote progression of muscle invasive bladder cancer. .


Frequent downregulation of LRRC26 by epigenetic alterations is involved in the malignant progression of triple-negative breast cancer.

Triple-negative breast cancer (TNBC), defined as breast cancer lacking estrogen- and progesterone‑receptor expression and human epidermal growth factor receptor 2 (HER2) amplification, is a heterogeneous disease. RNA-sequencing analysis of 15 TNBC specimens and The Cancer Genome Atlas-TNBC dataset analysis identified the frequent downregulation of leucine-rich repeat-containing 26 (LRRC26), which negatively regulates nuclear factor-κB (NF-κB) signaling, in TNBC tissues. Quantitative polymerase chain reaction and bisulfite pyrosequencing analyses revealed that LRRC26 was frequently silenced in TNBC tissues and cell lines as a result of promoter methylation. LRRC26 expression was restored by 5-aza-2'-deoxycytidine (5'-aza-dC) treatment in HCC1937 TNBC cells, which lack LRRC26 expression. Notably, small interfering RNA-mediated knockdown of LRRC26 expression significantly enhanced the anchorage-independent growth, invasion and migration of HCC70 cells, whereas ectopic overexpression of LRRC26 in BT20 cells suppressed their invasion and migration. Conversely, neither knockdown nor overexpression of LRRC26 had an effect on cell viability in the absence of tumor necrosis factor-α (TNF-α) stimulation. Meanwhile, overexpression of LRRC26 caused the reduction of TNF-α-mediated NF-κB luciferase reporter activity, whereas depleting LRRC26 expression resulted in the upregulation of TNF-α-mediated NF-κB downstream genes [interleukin-6 (IL-6), IL-8 and C-X-C motif chemokine ligand-1]. Taken together, these findings demonstrate that LRRC26 is frequently downregulated in TNBC due to DNA methylation and that it suppresses the TNF-α-independent anchorage-independent growth, invasion and migration of TNBC cells. Loss of LRRC26 function may be a critical event in the aggressiveness of TNBC cells through a TNF-α/NF-κB-independent mechanism.


Present status and future perspective of peptide-based vaccine therapy for urological cancer.

Use of peptide-based vaccines as therapeutics aims to elicit immune responses through antigenic epitopes derived from tumor antigens. Peptide-based vaccines are easily synthesized and lack significant side-effects when given in vivo. Peptide-based vaccine therapy against several cancers including urological cancers has made progress for several decades, but there is no worldwide approved peptide vaccine. Peptide vaccines were also shown to induce a high frequency of immune response in patients accompanied by clinical efficacy. These data are discussed in light of the recent progression of immunotherapy caused by the addition of immune checkpoint inhibitors thus providing a general picture of the potential therapeutic efficacy of peptide-based vaccines and their combination with other biological agents. In this review, we discuss the mechanism of the antitumor effect of peptide-based vaccine therapy, development of our peptide vaccine, recent clinical trials using peptide vaccines for urological cancers, and perspectives of peptide-based vaccine therapy.


Molecular targeting of cell-permeable peptide inhibits pancreatic ductal adenocarcinoma cell proliferation.


Tumor size and proliferative marker geminin rather than Ki67 expression levels significantly associated with maximum uptake of 18F-deoxyglucose levels on positron emission tomography for breast cancers.

It has been well established that maximum standardized uptake value (SUVmax) for 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) is clinically useful for evaluating treatment efficacy as well as predicting prognosis of breast cancer patients. Although SUVmax reflects increased glucose uptake and metabolism possibly induced by activation of growth factor signaling or TP53 dysfunction, tumor characteristics of SUVmax-high breast cancers remain to be elucidated. For the present study, we used immunohistochemical staining to investigate expressions of phospho-ribosomal protein S6 (pS6, downstream molecule of phosphatidyl inositol 3-kinase/Akt/mammalian target of the rapamycin/S6K pathway) and phosphor-p44/42 mitogen-activated protein kinase (pMAPK). Expression levels of TP53 and proliferative marker geminin as well as Ki67 were also examined by means of immunostaining in 163 invasive breast cancers. Cutoff values were set at 10% for pS6, 20% for pMAPK and TP53, and 4% for geminin. The SUVmax levels were significantly higher in the pS6-positive (p = 0.0173), TP53-positive (p = 0.0207) and geminin-high cancers (p<0.0001), but there was no significant association between pMAPK expression levels and SUVmax levels. Multivariable analysis showed that a high geminin level (odds ratio: 6.497, 95% confidence interval: 2.427-19.202, p = 0.0001) and large tumor size (6.438, 2.224-20.946, p = 0.0005) were significantly and independently associated with SUVmax-high. Univariable but not multivariable analysis indicated that Ki67-high significantly correlated with SUVmax-high. Twenty of 23 (87.0%) breast cancers with tumor size >2cm and geminin-high showed SUVmax-high, while only 6 of 49 (12.2%) breast cancers 2cm in size and with low geminin levels were SUVmax-high. In conclusion, we could determine that breast cancers with a large tumor and a geminin-high rather than Ki67-high proliferative marker were significantly associated with high levels of SUVmax. These findings may signify that SUVmax reflects tumor characteristics with high proliferative activity but not activation of mTOR/S6K and MAPK pathways or increased glucose metabolism due to dysfunction of TP53.


A-kinase anchoring protein BIG3 coordinates oestrogen signalling in breast cancer cells.

Approximately 70% of breast cancer cells express oestrogen receptor alpha (ER). Previous studies have shown that the Brefeldin A-inhibited guanine nucleotide-exchange protein 3-prohibitin 2 (BIG3-PHB2) complex has a crucial role in these cells. However, it remains unclear how BIG3 regulates the suppressive activity of PHB2. Here we demonstrate that BIG3 functions as an A-kinase anchoring protein that binds protein kinase A (PKA) and the isoform of the catalytic subunit of protein phosphatase 1 (PP1C), thereby dephosphorylating and inactivating PHB2. E2-induced PKA-mediated phosphorylation of BIG3-S305 and -S1208 serves to enhance PP1C activity, resulting in E2/ER signalling activation via PHB2 inactivation due to PHB2-S39 dephosphorylation. Furthermore, an analysis of independent cohorts of ER-positive breast cancers patients reveal that both BIG3 overexpression and PHB2-S39 dephosphorylation are strongly associated with poor prognosis. This is the first demonstration of the mechanism of E2/ER signalling activation via the BIG3-PKA-PP1C tri-complex in breast cancer cells.


The prediction models for postoperative overall survival and disease-free survival in patients with breast cancer.

The goal of this study is to establish a method for predicting overall survival (OS) and disease-free survival (DFS) in breast cancer patients after surgical operation. The gene expression profiles of cancer tissues from the patients, who underwent complete surgical resection of breast cancer and were subsequently monitored for postoperative survival, were analyzed using cDNA microarrays. We detected seven and three probes/genes associated with the postoperative OS and DFS, respectively, from our discovery cohort data. By incorporating these genes associated with the postoperative survival into MammaPrint genes, often used to predict prognosis of patients with early-stage breast cancer, we constructed postoperative OS and DFS prediction models from the discovery cohort data using a Cox proportional hazard model. The predictive ability of the models was evaluated in another independent cohort using Kaplan-Meier (KM) curves and the area under the receiver operating characteristic curve (AUC). The KM curves showed a statistically significant difference between the predicted high- and low-risk groups in both OS (log-rank trend test P = 0.0033) and DFS (log-rank trend test P = 0.00030). The models also achieved high AUC scores of 0.71 in OS and of 0.60 in DFS. Furthermore, our models had improved KM curves when compared to the models using MammaPrint genes (OS: P = 0.0058, DFS: P = 0.00054). Similar results were observed when our model was tested in publicly available datasets. These observations indicate that there is still room for improvement in the current methods of predicting postoperative OS and DFS in breast cancer.


Stapled BIG3 helical peptide ERAP potentiates anti-tumour activity for breast cancer therapeutics.

Estradiol (E2) and the oestrogen receptor-alpha (ER) signalling pathway play pivotal roles in the proliferative activity of breast cancer cells. Recent findings show that the brefeldin A-inhibited guanine nucleotide-exchange protein 3-prohibitin 2 (BIG3-PHB2) complex plays a crucial role in E2/ER signalling modulation in breast cancer cells. Moreover, specific inhibition of the BIG3-PHB2 interaction using the ER activity-regulator synthetic peptide (ERAP: 165-177 amino acids), derived from -helical BIG3 sequence, resulted in a significant anti-tumour effect. However, the duration of this effect was very short for viable clinical application. We developed the chemically modified ERAP using stapling methods (stapledERAP) to improve the duration of its antitumour effects. The stapledERAP specifically inhibited the BIG3-PHB2 interaction and exhibited long-lasting suppressive activity. Its intracellular localization without the membrane-permeable polyarginine sequence was possible via the formation of a stable -helix structure by stapling. Tumour bearing-mice treated daily or weekly with stapledERAP effectively prevented the BIG3-PHB2 interaction, leading to complete regression of E2-dependent tumours in vivo. Most importantly, combination of stapledERAP with tamoxifen, fulvestrant, and everolimus caused synergistic inhibitory effects on growth of breast cancer cells. Our findings suggested that the stapled ERAP may be a promising anti-tumour drug to suppress luminal-type breast cancer growth.


Protein kinase A inhibition facilitates the antitumor activity of xanthohumol, a valosin-containing protein inhibitor.

Xanthohumol (XN), a simple prenylated chalcone, can be isolated from hops and has the potential to be a cancer chemopreventive agent against several human tumor cell lines. We previously identified valosin-containing protein (VCP) as a target of XN; VCP can also play crucial roles in cancer progression and prognosis. Therefore, we investigated the molecular mechanisms governing the contribution of VCP to the antitumor activity of XN. Several human tumor cell lines were treated with XN to investigate which human tumor cell lines are sensitive to XN. Several cell lines exhibited high sensitivity to XN both in vitro and in vivo. shRNA screening and bioinformatics analysis identified that the inhibition of the adenylate cyclase (AC) pathway synergistically facilitated apoptosis induced by VCP inhibition. These results suggest there is crosstalk between the AC pathway and VCP function, and targeting both VCP and the AC pathway is a potential chemotherapeutic strategy for a subset of tumor cells. This article is protected by copyright. All rights reserved.


Immunohistochemical Ki67 after short-term hormone therapy identifies low-risk breast cancers as reliably as genomic markers.

IHC based post-Ki67 levels may have distinct predictive power compared with the naïve IHC Ki67. Future studies with larger cohorts and longer follow-up periods may be needed to validate our results.


Sex- and age-dependent gene expression in human liver: An implication for drug-metabolizing enzymes.

Sex and age differences in hepatic expression of drug-metabolizing enzyme genes could cause variations in drug metabolism, but has not been fully elucidated, especially in Asian population. In this study, the global expression of human hepatic genes was analyzed by microarrays in 40 Japanese subjects (27 males and 13 females). Thirty-five sex-biased genes were identified (P < 0.005). Whereas, 60 age-biased genes in two age groups, <60 years and ≥70 years (P < 0.001), were identified in males. By Gene Ontology analysis, the sex-biased genes were related to protein catabolism and modification, while the age-biased genes were related to transcription regulation and cell death. Quantitative polymerase chain reaction confirmed the female-biased expression of drug-metabolizing enzyme genes BChE, CYP4X1, and SULT1E1 (≥1.5-fold, P < 0.05). Further analysis of drug-metabolizing enzyme genes indicated that expression of CYP2A6 and CYP3A4 in females in the ≥70 age group was less than in the <60 age group (≥1.5-fold, P < 0.05), and this trend was also observed for PXR expression in males (≥1.5-fold, P < 0.05). The results presented provide important insights into hepatic physiology and function, especially drug metabolism, with respect to sex and age.


Effective induction of cytotoxic T cells recognizing an epitope peptide derived from hypoxia-inducible protein 2 (HIG2) in patients with metastatic renal cell carcinoma.

HIG2-9-4 peptide vaccine treatment was tolerable and effectively induced peptide-specific CTLs in RCC patients. This novel peptide vaccine therapy for RCC is promising.

Vaccinations with HIG2-9-4 peptide could be well tolerated without any serious systemic adverse events. Peptide-specific cytotoxic T lymphocyte (CTL) responses were detected in eight of the nine patients. Doses of 1.0 or 3.0 mg/body seemed to induce a CTL response better than did a dose of 0.5 mg/body, although the number of patients was too small to draw a firm conclusion. The disease control rate (stable disease for ≥4 months) was 77.8 %, and the median progression-free survival time was 10.3 months.


Overexpression of C16orf74 is involved in aggressive pancreatic cancers.

Clinical outcome of pancreatic ductal adenocarcinoma (PDAC) has not been improved in the last three decades due to the lack of effective molecular-targeted drugs. To identify a novel therapeutic target for PDAC, we have performed genome-wide anamysis and found that Homo sapiens chromosome 16 open reading frame 74 (C16orf74) was up-regulated in the vast majority of PDAC. Overexpression of C16orf74protein detected by immunohistochemical analysis was an independent prognostic factor for patients with PDAC. The knockdown of endogenous C16orf74 expression in the PDAC cell lines KLM-1 and PK-59 by vector-based small hairpin-RNA (shRNA) drastically attenuated the growth of those cells, whereas ectopic C16orf74 overexpression in HEK293T and NIH3T3 cells promoted cell growth and invasion, respectively. More importantly, the endogenous threonine 44 (T44)-phosphorylated form of C16orf74 interacted with the protein phosphatase 3 catalytic subunit alpha (PPP3CA) via the PDIIIT sequence in the PPP3CA-binding motif within the middle portion of C16orf74 in PDAC cells. The overexpression of mutants of C16orf74 lacking the PDIIIT sequence or T44 phosphorylation resulted in the suppression of invasive activity compared with wild-type C16orf74, indicating that their interaction should be indispensable for PDAC cell invasion. These results suggest that C16orf74 plays an important role for PDAC invasion and proliferation, and is a promising target for a specific treatment for patients with PDAC.


Clonal expansion of antitumor T cells in breast cancer correlates with response to neoadjuvant chemotherapy.

The immune microenvironment of tumor plays a critical role in therapeutic responses to chemotherapy. Cancer tissues are composed of a complex network between antitumor and pro-tumor immune cells and molecules; therefore a comprehensive analysis of the tumor immune condition is imperative for better understanding of the roles of the immune microenvironment in anticancer treatment response. In this study, we performed T cell receptor (TCR) repertoire analysis of tumor infiltrating T cells (TILs) in cancer tissues of pre- and post-neoadjuvant chemotherapy (NAC) from 19 breast cancer patients; five cases showed CR (complete response), ten showed PR (partial response), and four showed SD/PD (stable disease/progressive disease) to the treatment. From the TCR sequencing results, we calculated the diversity index of the TCRβ chain and found that clonal expansion of TILs could be detected in patients who showed CR or PR to NAC. Noteworthy, the diversity of TCR was further reduced in the post-NAC tumors of CR patients. Our quantitative RT-PCR also showed that expression ratio of CD8/Foxp3 was significantly elevated in the post-NAC tumors of CR cases (p=0.0032), indicating that antitumor T cells were activated and enriched in these tumors. Collectively, our findings suggest that the clonal expansion of antitumor T cells may be a critical factor associated with response to chemotherapy and that their TCR sequences might be applicable for the development of TCR-engineered T cells treatment for individual breast cancer patients when their tumors relapse.


High levels at baseline of serum pyridinoline crosslinked carboxyterminal telopeptide of type I collagen are associated with worse prognosis for breast cancer patients.

It is speculated that adjuvant use of bisphosphonate reduces recurrence in breast cancer patients through suppression of bone resorption. To determine the prognostic impact of bone resorption markers, we investigated serum levels of the pyridinoline crosslinked carboxyterminal telopeptide of type I collagen (1CTP) and N-terminal crosslinking telopeptides of type I collagen (NTX). 1CTP and NTX were measured at baseline (before operation or neoadjuvant therapies) and afterward in 469 patients operated on breast cancer. The optimal cutoff value of 1CTP for relapse-free survival (RFS) was set at 3.6 ng/ml with an area under the receiver operating characteristics curve of 0.641 [95 % confidence interval (CI) = 0.560-0.721; p = 0.0011]. However, we were unable to determine a significant cutoff value for NTX. RFS was significantly worse for 1CTP-high patients with than for those with low levels of 1CTP (p = 0.0002). Multivariate analysis with tumor size, lymph node metastasis, and nuclear grade showed that 1CTP was a significant independent prognostic factor (hazard ratio = 2.04, 95 % CI = 1.13-3.68; p = 0.018). Worse prognosis for the subset with high 1CTP levels applied only to postmenopausal patients (p = 0.0002). RFS of 130 patients whose 1CTP changed from low at baseline to high at 6 months postoperatively showed RFS almost as poor as that for patients with high 1CTP throughout. These findings suggest that 1CTP may be useful not only for identifying patients with unfavorable prognosis, but also for selecting patients who may benefit from administration of bone-modifying agents in an adjuvant setting.


BIG3 Inhibits the Estrogen-Dependent Nuclear Translocation of PHB2 via Multiple Karyopherin-Alpha Proteins in Breast Cancer Cells.

We recently reported that brefeldin A-inhibited guanine nucleotide-exchange protein 3 (BIG3) binds Prohibitin 2 (PHB2) in cytoplasm, thereby causing a loss of function of the PHB2 tumor suppressor in the nuclei of breast cancer cells. However, little is known regarding the mechanism by which BIG3 inhibits the nuclear translocation of PHB2 into breast cancer cells. Here, we report that BIG3 blocks the estrogen (E2)-dependent nuclear import of PHB2 via the karyopherin alpha (KPNA) family in breast cancer cells. We found that overexpressed PHB2 interacted with KPNA1, KPNA5, and KPNA6, thereby leading to the E2-dependent translocation of PHB2 into the nuclei of breast cancer cells. More importantly, knockdown of each endogenous KPNA by siRNA caused a significant inhibition of E2-dependent translocation of PHB2 in BIG3-depleted breast cancer cells, thereby enhancing activation of estrogen receptor alpha (ER). These data indicated that BIG3 may block the KPNAs (KPNA1, KPNA5, and KPNA6) binding region(s) of PHB2, thereby leading to inhibition of KPNAs-mediated PHB2 nuclear translocation in the presence of E2 in breast cancer cells. Understanding this regulation of PHB2 nuclear import may provide therapeutic strategies for controlling E2/ER signals in breast cancer cells.


Therapeutic advances in BIG3-PHB2 inhibition targeting the crosstalk between estrogen and growth factors in breast cancer.

Our previous studies demonstrated that specific inhibition of the BIG3-PHB2 complex, which is a critical modulator in estrogen (E2) signaling, using ERAP, a dominant negative peptide inhibitor, leads to suppression of E2-dependent estrogen receptor (ER) alpha activation through the reactivation of the tumor suppressive activity of PHB2. Here, we report that ERAP has significant suppressive effects against synergistic activation caused by the crosstalk between E2 and growth factors associated with intrinsic or acquired resistance to anti-estrogen tamoxifen in breast cancer cells. Intrinsic PHB2 released from BIG3 by ERAP effectively disrupted each interaction of membrane-associated ERα and insulin-like growth factor 1 receptor beta (IGF-1Rβ), EGFR, PI3K or human epidermal growth factor 2 (HER2) in the presence of E2 and the growth factors IGF or EGF, followed by inhibited the activation of IGF-1Rβ, EGFR or HER2, and reduced Akt, MAPK and ERα phosphorylation levels, resulting in significant suppression of proliferation of ERα-positive breast cancer cells in vitro and in vivo. More importantly, combined treatment with ERAP and tamoxifen led to a synergistic suppression of signaling that was activated by crosstalk between E2 and growth factors or HER2 amplification. Taken together, our findings suggest that the specific inhibition of BIG3-PHB2 is a novel potential therapeutic approach for the treatment of tamoxifen-resistant breast cancers activated by the crosstalk between E2 and growth factor signaling, especially in premenopausal women.


Activation of mTOR/S6K But Not MAPK Pathways Might Be Associated With High Ki-67, ER(+), and HER2(-) Breast Cancer.

From our findings, we have concluded that the pS6 expression level is associated with the characteristics of breast cancer with high Ki-67 expression. Because these associations were observed, irrespective of menopausal status, the biologic difference seems to be less affected by estrogen signaling than by activation of S6 protein, especially in terms of proliferation. Our findings have also indicated that targeting the mTOR/S6K pathway might be a useful strategy for the treatment of ER(+)/HER2(-) breast cancer with high Ki-67 expression.


Xanthohumol suppresses oestrogen-signalling in breast cancer through the inhibition of BIG3-PHB2 interactions.

Xanthohumol (XN) is a natural anticancer compound that inhibits the proliferation of oestrogen receptor- (ER)-positive breast cancer cells. However, the precise mechanism of the antitumour effects of XN on oestrogen (E2)-dependent cell growth, and especially its direct target molecule(s), remain(s) largely unknown. Here, we focus on whether XN directly binds to the tumour suppressor protein prohibitin 2 (PHB2), forming a novel natural antitumour compound targeting the BIG3-PHB2 complex and acting as a pivotal modulator of E2/ER signalling in breast cancer cells. XN treatment effectively prevented the BIG3-PHB2 interaction, thereby releasing PHB2 to directly bind to both nuclear- and cytoplasmic ER. This event led to the complete suppression of the E2-signalling pathways and ER-positive breast cancer cell growth both in vitro and in vivo, but did not suppress the growth of normal mammary epithelial cells. Our findings suggest that XN may be a promising natural compound to suppress the growth of luminal-type breast cancer.


Early growth response 4 is involved in cell proliferation of small cell lung cancer through transcriptional activation of its downstream genes.

Small cell lung cancer (SCLC) is aggressive, with rapid growth and frequent bone metastasis; however, its detailed molecular mechanism remains poorly understood. Here, we report the critical role of early growth factor 4 (EGR4), a DNA-binding, zinc-finger transcription factor, in cell proliferation of SCLC. EGR4 overexpression in HEK293T cells conferred significant upregulation of specific splice variants of the parathyroid hormone-related protein (PTHrP) gene, resulting in enhancement of the secretion of PTHrP protein, a known mediator of osteolytic bone metastasis. More importantly, depletion of EGR4 expression by siRNA significantly suppressed growth of the SCLC cell lines, SBC-5, SBC-3 and NCI-H1048. On the other hand, introduction of EGR4 into NIH3T3 cells significantly enhanced cell growth. We identified four EGR4 target genes, SAMD5, RAB15, SYNPO and DLX5, which were the most significantly downregulated genes upon depletion of EGR4 expression in all of the SCLC cells examined, and demonstrated the direct recruitment of EGR4 to their promoters by ChIP and luciferase reporter analysis. Notably, knockdown of the expression of these genes by siRNA remarkably suppressed the growth of all the SCLC cells. Taken together, our findings suggest that EGR4 likely regulates the bone metastasis and proliferation of SCLC cells via transcriptional regulation of several target genes, and may therefore be a promising target for the development of anticancer drugs for SCLC patients.


Identification of novel epigenetically inactivated gene PAMR1 in breast carcinoma.

Development of cancer is a complex process involving multiple genetic and epigenetic alterations. In our microarray analysis of 81 breast carcinoma specimens, we identified peptidase domain containing associated with muscle regeneration 1 (PAMR1) as being frequently suppressed in breast cancer tissues. PAMR1 expression was also reduced in all tested breast cancer cell lines, while PAMR1 was expressed moderately in normal breast tissues and primary mammary epithelial cells. DNA sequencing of the PAMR1 promoter after sodium bisulfite treatment revealed that CpG sites were hypermethylated in the breast cancer tissues and cell lines. PAMR1 expression was restored by 5-aza-2' deoxycytidine treatment, demonstrating that promoter hypermethylation contributed to PAMR1 inactivation in the breast cancer cells. In addition, ectopic expression of PAMR1 markedly suppressed cancer cell growth. In summary, our study identified PAMR1 as a putative tumor suppressor which was frequently inactivated by promoter hypermethylation in breast cancer tissues.


Brefeldin A-inhibited guanine nucleotide-exchange protein 3 (BIG3) is predicted to interact with its partner through an ARM-type -helical structure.

The combined results of the structure and interaction prediction led to a novel hypothesis that one of the predicted helices of BIG3 might play an important role in binding to PHB2 and thereby preventing its translocation to the nucleus. This hypothesis has been subsequently verified experimentally.


Identification of an HLA-A2-restricted epitope peptide derived from hypoxia-inducible protein 2 (HIG2).

We herein report the identification of an HLA-A2 supertype-restricted epitope peptide derived from hypoxia-inducible protein 2 (HIG2), which is known to be a diagnostic marker and a potential therapeutic target for renal cell carcinoma. Among several candidate peptides predicted by the HLA-binding prediction algorithm, HIG2-9-4 peptide (VLNLYLLGV) was able to effectively induce peptide-specific cytotoxic T lymphocytes (CTLs). The established HIG2-9-4 peptide-specific CTL clone produced interferon- (IFN-) in response to HIG2-9-4 peptide-pulsed HLA-A*02:01-positive cells, as well as to cells in which HLA-A*02:01 and HIG2 were exogenously introduced. Moreover, the HIG2-9-4 peptide-specific CTL clone exerted cytotoxic activity against HIG2-expressing HLA-A*02:01-positive renal cancer cells, thus suggesting that the HIG2-9-4 peptide is naturally presented on HLA-A*02:01 of HIG-2-expressing cancer cells and is recognized by CTLs. Furthermore, we found that the HIG2-9-4 peptide could also induce CTLs under HLA-A*02:06 restriction. Taken together, these findings indicate that the HIG2-9-4 peptide is a novel HLA-A2 supertype-restricted epitope peptide that could be useful for peptide-based immunotherapy against cancer cells with HIG2 expression.


Involvement of B3GALNT2 overexpression in the cell growth of breast cancer.

A number of glycosyltransferases have been identified and biologically characterized in cancer cells, yet their exact pathophysiological functions are largely unknown. Here, we report the critical role of 1,3-N-acetylgalactosaminyltransferase II (B3GALNT2), which transfers N-acetylgalactosamine (GalNAc) in a 1,3 linkage to N-acetylglucosamine, in the growth of breast cancer cells. Comprehensive transcriptomics, quantitative PCR and northern blot analyses indicated this molecule to be exclusively upregulated in the majority of breast cancers. Knockdown of B3GALNT2 expression by small interfering RNA attenuated cell growth and induced apoptosis in breast cancer cells. Overexpression of B3GALNT2 in HEK293T cells prompted secretion of the gene product into the culture medium, suggesting that B3GALNT2 is potentially a secreted protein. Furthermore, we demonstrated that B3GALNT2 is N-glycosylated on both Asn-116 and Asn-174 and that this modification is necessary for its secretion in breast cancer cells. Our findings suggest that this molecule represents a promising candidate for the development of a novel therapeutic targeting drug and a potential diagnostic tumor marker for patients with breast cancer, especially TNBC.


Genome-wide association study of breast cancer in the Japanese population.

Breast cancer is the most common malignancy among women in worldwide including Japan. Several studies have identified common genetic variants to be associated with the risk of breast cancer. Due to the complex linkage disequilibrium structure and various environmental exposures in different populations, it is essential to identify variants associated with breast cancer in each population, which subsequently facilitate the better understanding of mammary carcinogenesis. In this study, we conducted a genome-wide association study (GWAS) as well as whole-genome imputation with 2,642 cases and 2,099 unaffected female controls. We further examined 13 suggestive loci (P<1.0×10(-5)) using an independent sample set of 2,885 cases and 3,395 controls and successfully validated two previously-reported loci, rs2981578 (combined P-value of 1.31×10(-12), OR = 1.23; 95% CI = 1.16-.30) on chromosome 10q26 (FGFR2), rs3803662 (combined P-value of 2.79×10(-11), OR = 1.21; 95% CI = 1.15-.28) and rs12922061 (combined P-value of 3.97×10(-10), OR = 1.23; 95% CI = 1.15-.31) on chromosome 16q12 (TOX3-LOC643714). Weighted genetic risk score on the basis of three significantly associated variants and two previously reported breast cancer associated loci in East Asian population revealed that individuals who carry the most risk alleles in category 5 have 2.2 times higher risk of developing breast cancer in the Japanese population than those who carry the least risk alleles in reference category 1. Although we could not identify additional loci associated with breast cancer, our study utilized one of the largest sample sizes reported to date, and provided genetic status that represent the Japanese population. Further local and international collaborative study is essential to identify additional genetic variants that could lead to a better, accurate prediction for breast cancer.


Influence of body mass index on clinicopathological factors including estrogen receptor, progesterone receptor, and Ki67 expression levels in breast cancers.

Higher BMI might influence aggressive tumor characteristics among premenopausal patients, but its influence on ER, PR, and Ki67 expression levels seems to be limited.

Premenopausal patients with high BMI showed a significantly higher frequency of lymph node metastasis (46.4 % vs. 22.9 %, P = 0.005) and tended to have a larger tumor size (P = 0.05) and higher nuclear grade (P = 0.07) than those with low BMI. These differences were not observed among postmenopausal patients. BMI was not associated with distribution of breast cancer subtypes, and ER, progesterone receptor (PR), and Ki67 expression levels of each subtype showed no differences between high and low BMI among premenopausal patients.

International Journal of Clinical Oncology


Molecular features of triple negative breast cancer cells by genome-wide gene expression profiling analysis.

Triple negative breast cancer (TNBC) has a poor outcome due to the lack of beneficial therapeutic targets. To clarify the molecular mechanisms involved in the carcinogenesis of TNBC and to identify target molecules for novel anticancer drugs, we analyzed the gene expression profiles of 30 TNBCs as well as 13 normal epithelial ductal cells that were purified by laser-microbeam microdissection. We identified 301 and 321 transcripts that were significantly upregulated and downregulated in TNBC, respectively. In particular, gene expression profile analyses of normal human vital organs allowed us to identify 104 cancer-specific genes, including those involved in breast carcinogenesis such as NEK2, PBK and MELK. Moreover, gene annotation enrichment analysis revealed prominent gene subsets involved in the cell cycle, especially mitosis. Therefore, we focused on cell cycle regulators, asp (abnormal spindle) homolog, microcephaly-associated (Drosophila) (ASPM) and centromere protein K (CENPK) as novel therapeutic targets for TNBC. Small-interfering RNA-mediated knockdown of their expression significantly attenuated TNBC cell viability due to G1 and G2/M cell cycle arrest. Our data will provide a better understanding of the carcinogenesis of TNBC and could contribute to the development of molecular targets as a treatment for TNBC patients.


The transcription factor Sp3 regulates the expression of a metastasis-related marker of sarcoma, actin filament-associated protein 1-like 1 (AFAP1L1).

We previously identified actin filament-associated protein 1-like 1 (AFAP1L1) as a metastasis-predicting marker from the gene-expression profiles of 65 spindle cell sarcomas, and demonstrated the up-regulation of AFAP1L1 expression to be an independent risk factor for distant metastasis in multivariate analyses. Little is known, however, about how the expression of AFAP1L1 is regulated. Luciferase reporter assays showed tandem binding motives of a specificity protein (Sp) located at -85 to -75 relative to the transcriptional start site to be essential to the promoter activity. Overexpression of Sp1 and Sp3 proteins transactivated the proximal AFAP1L1 promoter construct, and electrophoretic mobility shift assays showed that both Sp1 and Sp3 were able to bind to this region in vitro. Chromatin immunoprecipitation experiments, however, revealed that Sp3 is the major factor binding to the proximal promoter region of the AFAP1L1 gene in AFAP1L1- positive cells. Treatment with mithramycin A, an inhibitor of proteins binding to GC-rich regions, prevented Sp3 from binding to the proximal promoter region of AFAP1L1 and decreased its expression in a dose-dependent manner. Finally, knocking down Sp3 using small inhibitory RNA duplex (siRNA) reduced AFAP1L1 expression significantly, which was partially restored by expressing siRNA-resistant Sp3. These findings indicate a novel role for Sp3 in sarcomas as a driver for expression of the metastasis-related gene AFAP1L1.


Targeting BIG3-PHB2 interaction to overcome tamoxifen resistance in breast cancer cells.

The acquisition of endocrine resistance is a common obstacle in endocrine therapy of patients with oestrogen receptor- (ER)-positive breast tumours. We previously demonstrated that the BIG3-PHB2 complex has a crucial role in the modulation of oestrogen/ER signalling in breast cancer cells. Here we report a cell-permeable peptide inhibitor, called ERAP, that regulates multiple ER-signalling pathways associated with tamoxifen resistance in breast cancer cells by inhibiting the interaction between BIG3 and PHB2. Intrinsic PHB2 released from BIG3 by ERAP directly binds to both nuclear- and membrane-associated ER, which leads to the inhibition of multiple ER-signalling pathways, including genomic and non-genomic ER activation and ER phosphorylation, and the growth of ER-positive breast cancer cells both in vitro and in vivo. More importantly, ERAP treatment suppresses tamoxifen resistance and enhances tamoxifen responsiveness in ER-positive breast cancer cells. These findings suggest inhibiting the interaction between BIG3 and PHB2 may be a new therapeutic strategy for the treatment of luminal-type breast cancer.


A commentary on Analysis of ZNF350/ZBRK1 promoter variants and breast cancer susceptibility in non-BRCA1/2 French Canadian breast cancer families.


DDX31 regulates the p53-HDM2 pathway and rRNA gene transcription through its interaction with NPM1 in renal cell carcinomas

Studies of renal cell carcinoma (RCC) have led to the development of new molecular-targeted drugs but its oncogenic origins remain poorly understood. Here, we report the identification and critical roles in renal carcinogenesis for DDX31, a novel nucleolar protein upregulated in the vast majority of human RCC. Immunohistochemical overexpression of DDX31 was an independent prognostic factor for patients with RCC. RNA interference (RNAi)-mediated attenuation of DDX31 in RCC cells significantly suppressed outgrowth, whereas ectopic DDX31 overexpression in human 293 kidney cells drove their proliferation. Endogenous DDX31 interacted and colocalized with nucleophosmin (NPM1) in the nucleoli of RCC cells, and attenuation of DDX31 or NPM1 expression decreased pre-ribosomal RNA biogenesis. Notably, in DDX31-attenuated cells, NPM1 was translocated from nucleoli to the nucleoplasm or cytoplasm where it bound to HDM2. As a result, HDM2 binding to p53 was reduced, causing p53 stablization with concomitant G(1) phase cell-cycle arrest and apoptosis. Taken together, our findings define a mechanism through which control of the DDX31-NPM1 complex is likely to play critical roles in renal carcinogenesis.


A genome-wide association study identifies a genetic variant in the SIAH2 locus associated with hormonal receptor-positive breast cancer in Japanese.

In Japan, breast cancer is the most common cancer among women and the second leading cause of cancer death among women worldwide. To identify genetic variants associated with the disease susceptibility, we performed a genome-wide association study (GWAS) using a total of 1086 Japanese female patients with hormonal receptor-positive (HRP) breast cancer and 1816 female controls. We selected 33 single-nucleotide polymorphisms (SNPs) with suggestive associations in GWAS (P-value of <1 × 10(-4)) as well as 4 SNPs that were previously implicated their association with breast cancer for further replication by an independent set of 1653 cases and 2797 controls. We identified significant association of the disease with a SNP rs6788895 (P(combined) of 9.43 × 10(-8) with odds ratio (OR) of 1.22) in the SIAH2 (intron of seven in absentia homolog 2) gene on chromosome 3q25.1 where the involvement in estrogen-dependent diseases was suggested. In addition, rs3750817 in intron 2 of the fibroblast growth factor receptor 2 gene, which was reported to be associated with breast cancer susceptibility, was significantly replicated with P(combined) of 8.47 × 10(-8) with OR=1.22. Our results suggest a novel susceptibility locus on chromosome 3q25.1 for a HRP breast cancer.


Cancer Peptide Vaccine Therapy Developed from Oncoantigens Identified through Genome-wide Expression Profile Analysis for Bladder Cancer.

The novel approach adopted in the treatment with peptide vaccines is considered to be a promising therapy for bladder cancer.


Biological characteristics of luminal subtypes in pre- and postmenopausal estrogen receptor-positive and HER2-negative breast cancers.

Estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancers can be divided into luminal A and luminal B subtypes based on Ki67 expression levels. However, the biological differences in ER and progesterone receptor (PR) expression levels between these luminal subtypes are not clear. We examined immunohistochemical expression levels of ER, PR, and Ki67 in 180 ER-positive/HER2-negative breast cancers while taking menopausal status into account. Breast cancers were divided according to ER and PR levels (H: >50%, L: ≤ 50%), and luminal A and B were classified by the Ki67 labeling index (A: Ki67 <14%, B: Ki67 ≥ 14%). When breast cancers were classified based on ER and PR levels, the distribution of pre- and postmenopausals was significantly different for luminal A (P < 0.0001), but not for luminal B cancers. As for luminal A, ER-H/PR-L cancers were rare among premenopausals (8%), but frequent among postmenopausals (54%). Correlation between ER and PR levels among luminal A cancers was strong in premenopausals but weak in postmenopausals. Since crosstalk with growth factor signaling is unlikely in luminal A, we speculate that intratumoral estrogen insufficiency contributed to the characteristics of postmenopausal ER-H/PR-L cancers. We speculate that the biological characteristics of luminal A cancers are influenced by the estrogen environment, but its influence on luminal B cancers may be limited. We believe these considerations constitute useful information for a better understanding of the biology of ER-positive-HER2-negetive breast cancers.

BACKGROUND: Estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negetive breast cancers can be divided into luminal A and luminal B subtypes based on Ki67 expression levels. However, the biological differences in ER and progesterone receptor (PR) expression levels between these luminal subtypes are not clear. METHODS: We examined immunohistochemical expression levels of ER, PR, and Ki67 in 180 ER-positive/HER2-negative breast cancers while taking menopausal status into account. Breast cancers were divided according to ER and PR levels (H: >50%, L: ≤50%), and luminal A and B were classified by the Ki67 labeling index (A: Ki67 <14%, B: Ki67 ≥14%). RESULTS: When breast cancers were classified based on ER and PR levels, the distribution of pre- and postmenopausals was significantly different for luminal A (P < 0.0001), but not for luminal B cancers. As for luminal A, ER-H/PR-L cancers were rare among premenopausals (8%), but frequent among postmenopausals (54%). Correlation between ER and PR levels among luminal A cancers was strong in premenopausals but weak in postmenopausals. Since crosstalk with growth factor signaling is unlikely in luminal A, we speculate that intratumoral estrogen insufficiency contributed to the characteristics of postmenopausal ER-H/PR-L cancers. CONCLUSION: We speculate that the biological characteristics of luminal A cancers are influenced by the estrogen environment, but its influence on luminal B cancers may be limited. We believe these considerations constitute useful information for a better understanding of the biology of ER-positive-HER2-negetive breast cancers.


Identification of genes potentially involved in bone metastasis by genome-wide gene expression profile analysis of non-small cell lung cancer in mice

Lung cancer is commonly associated with multi-organ metastasis, and the bone is a frequent metastatic site for lung cancer. However, the molecular mechanism of organ-specific metastasis remains poorly understood. To elucidate this issue, we analyzed in this study genome-wide gene expression profiles of 15 metastatic lesions from three organs (bone, lung and liver) in a mouse model with multi-organ metastasis properties of human non-small cell lung cancer cells (ACC-LC319/bone2), using a combination of laser-microbeam microdissection and DNA microarrays. We identified 299 genes that could potentially be involved in the organ-selective nature of lung cancer metastasis. Among them, 77 were bone-specifically expressed elements, including genes involved in cell adhesion, cytoskeleton/cell motility, extracellular matrix remodeling and cell-cell signaling as well as genes already known to be involved in the bone metastasis of breast cancers. Quantitative RT-PCR confirmed the specific upregulation of eight genes in bone metastasis tumors, suggesting that these genes may be involved in bone metastasis. Our findings should be helpful for a better understanding of the molecular aspects of the metastatic process in different organs, and could lead to molecular target-based anticancer drugs and prevention of metastasis, especially bone metastasis.


In vivo therapeutic effect of CDH3/P-cadherin-targeting radioimmunotherapy.

Our findings demonstrate that CDH3/P-cadherin-targeting RIT with (90)Y-MAb-6 is a promising strategy for the treatment for cancers expressing CDH3/P-cadherin.

Our in vivo results confirmed the specific binding of MAb-6 to tumor cells after intravenous injections of (111)In-labeled MAb-6 to mice with tumors expressing CDH3/P-cadherin. A single intravenous injection of (90)Y-MAb-6 (100 μCi) significantly suppressed tumor growth in mice with tumors expressing CDH3/P-cadherin. Furthermore, two injections of (90)Y-MAb-6 led to complete tumor regression in H1373-inoculated mice without any detectable toxicity.


Catalytic activity of MsbA reconstituted in nanodisc particles is modulated by remote interactions with the bilayer.

ATP-binding cassette (ABC) transporters couple hydrolysis of ATP with vectorial transport across the cell membrane. We have reconstituted ABC transporter MsbA in nanodiscs of various sizes and lipid compositions to test whether ATPase activity is modulated by the properties of the bilayer. ATP hydrolysis rates, Michaelis-Menten parameters, and dissociation constants of substrate analog ATP--S demonstrated that physicochemical properties of the bilayer modulated binding and ATPase activity. This is remarkable when considering that the catalytic unit is located ~50Å from the transmembrane region. Our results validated the use of nanodiscs as an effective tool to reconstitute MsbA in an active catalytic state, and highlighted the close relationship between otherwise distant transmembrane and ATPase modules.


Identification of AFAP1L1 as a prognostic marker for spindle cell sarcomas.

Spindle cell sarcomas consist of tumors with different biological features, of which distant metastasis is the most ominous sign for a poor prognosis. However, metastasis is difficult to predict on the basis of current histopathological analyses. We have identified actin filament-associated protein 1-like 1 (AFAP1L1) as a candidate for a metastasis-predicting marker from the gene expression profiles of 65 spindle cell sarcomas. A multivariate analysis determined that AFAP1L1 was an independent factor for predicting the occurrence of distant metastasis (P=0.0001), which was further confirmed in another set of 41 tumors by a quantitative mRNA expression analysis. Immunohistochemical staining using paraffin-embedded tumor tissues revealed that the metastasis-free rate was significantly better in tumors negative for AFAP1L1 (P=0.0093 by log-rank test). Knocking down the AFAP1L1 gene in sarcoma cells resulted in inhibition of the cell invasion, and forced expression of AFAP1L1 in immortalized human mesenchymal stem cells induced anchorage-independent growth and increased cell invasiveness with high activity levels of matrix metallopeptidase. Furthermore, tumor growth in vivo was accelerated in AFAP1L1-transduced sarcoma cell lines. These results suggest that AFAP1L1 has a role in the progression of spindle cell sarcomas and is a prognostic biomarker.


Polypeptide N-acetylgalactosaminyltransferase 6 disrupts mammary acinar morphogenesis through O-glycosylation of fibronectin.

A high expression of short and immature O-glycans is one of the prominent features of breast cancer cells, which would be attributed to the upregulated expression of glycosyltransferases. Therefore, a detailed elucidation of glycosyltransferases and their substrate(s) may improve our understandings for their roles in mammary carcinogenesis. Here we report that overexpression of polypeptide N-acetylgalactosaminyltransferase 6 (GALNT6), a glycosyltransferase involved in the initial step of O-glycosylation, has transformational potentials through disruptive acinar morphogenesis and cellular changes similar to epithelial-to-mesenchymal transition in normal mammary epithelial cell, MCF10A. As one of the critical O-glycan substrates, we identified fibronectin that was O-glycosylated in vivo and thereby stabilized by GALNT6. Because knockdown of fibronectin abrogated the disruptive proliferation caused by introduction of GALNT6 into epithelial cells, our findings suggest that GALNT6-fibronectin pathway should be a critical component for breast cancer development and progression.


Critical involvement of RQCD1 in the EGFR-Akt pathway in mammary carcinogenesis.

We previously reported an important role of RQCD1 in mammary carcinogenesis through the interaction with Grb10 interacting GYF protein 1 (GIGYF1), Grb10 interacting GYF protein 2 (GIGYF2) and growth factor receptor binding protein 10 (Grb10). In this study, we investigated the biological mechanism of RQCD1 in regulation of the Akt activity as the downstream signal of epidermal growth factor receptor (EGFR). Knockdown of RQCD1 reduced the Akt phosphorylation level that was induced by epidermal growth factor (EGF) stimulation. We found a possible formation of the big complex involved in the Akt activity including Akt, EGFR, GIGYF1 and GIGYF2, Grb10 and RQCD1. We subsequently defined that a region corresponding to 620-665th amino acids of GIGYF1 and 667-712th amino acids of GIGYF2 interacted with RQCD1. Furthermore, we found that RQCD1 was required for enhancement of the interaction of Grb10 with GIGYF1 and GIGYF2. Our findings in this study imply the functional mechanism of RQCD1 in the Akt activity regulation as a mediator in the EGFR-signaling pathway.


Critical roles of LGN/GPSM2 phosphorylation by PBK/TOPK in cell division of breast cancer cells.

To investigate the molecular mechanism of mammary carcinogenesis and identify novel molecular targets for breast cancer therapy, we analyzed genome-wide gene expression profiles of 81 clinical breast cancer samples. Here, we report the critical role of LGN/GPSM2 (Leu-Gly-Asn repeat-enriched protein/G-protein signaling modulator 2) in the growth of breast cancer cells. Semiquantitative RT-PCR and Northern blot analyses confirmed upregulation of LGN/GPSM2 in a large proportion of breast cancers. Immunocytochemical staining identified LGN/GPSM2 at the spindle in cells at metaphase, and at midzone and midbody in cytokinetic cells. Western blot analysis indicated the highest expression and the phosphorylated form of LGN/GPSM2 protein in G2/M phase. Treatment with small-interfering RNAs (siRNAs) targeting LGN/GPSM2 caused incompletion of cell division and resulted in significant growth suppression of breast cancer cells. We found that the 450th threonine (Thr450) of LGN/GPSM2 was phosphorylated by the serine/threonine kinase PBK/TOPK during mitosis. Overexpression of LGN/GPSM2-T450A in which Thr450 was substituted with alanine induced growth suppression and aberrant chromosomal segregation. These findings imply an important role of LGN/GPSM2 in cell division of breast cancer cells and suggest that the PBK/TOPK-LGN/GPSM2 pathway might be a promising molecular target for treatment of breast cancer.


Involvement of C12orf32 overexpression in breast carcinogenesis.

Through genome-wide gene expression profile analysis of breast cancer, we identified a gene, chromosome 12 open reading frame 32 (C12orf32), to be involved in mammary carcinogenesis. Semiquantitative RT-PCR and Northern blot analysis confirmed C12orf32 overexpression in breast cancer cells and its almost undetectable level of expression in normal human tissues. Immunocytochemical staining analysis using breast cancer cell lines revealed a cell cycle-dependent subcellular localization of endogenous C12orf32 protein. Depletion of C12orf32 expression by small-hairpin RNA interference significantly suppressed the growth of breast cancer cell lines possibly due to the inhibition of G1/S transition and subsequent cell death. Western blot analysis indicated that a C12orf32 protein of 35 kDa predicted from the cDNA sequences was processed to a 16-kDa protein of (C12orf32-p16) which was accumulated in most of breast cancer cell lines examined. Our data suggest that C12orf32 is a promising molecular target for the development of novel anticancer drugs such as peptide vaccines and siRNA drugs.


Cell-permeable peptide DEPDC1-ZNF224 interferes with transcriptional repression and oncogenicity in bladder cancer cells.

Bladder cancer is the second most common genitourinary cancer worldwide, yet its oncogenic origins remain poorly understood. The cancer-testis antigen DEPDC1 was shown recently to contribute to bladder cancer oncogenesis. In this study, we examined the biological functions of DEPDC1 and defined a potential therapeutic strategy to target this molecule. Coimmunoprecipitation and immunocytochemistry revealed that DEPDC1 interacted and colocalized with zinc finger transcription factor ZNF224, a known transcriptional repressor. Inhibiting this interaction with a cell-permeable peptide corresponding to the ZNF224-interacting domain in DEPDC1 induced apoptosis of bladder cancer cells in vitro and in vivo. By inhibiting DEPDC1-ZNF224 complex formation, this peptide triggered transcriptional activation of A20, a potent inhibitor of the NF-kappaB signaling pathway. Our findings indicate that the DEPDC1-ZNF224 complex is likely to play a critical role in bladder carcinogenesis.


Critical roles of mucin 1 glycosylation by transactivated polypeptide N-acetylgalactosaminyltransferase 6 in mammary carcinogenesis.

The structure of O-glycosylated proteins is altered in breast cancer cells, but the mechanisms of such an aberrant modification have been largely unknown. We here report critical roles of a novel druggable target, polypeptide N-acetylgalactosaminyltransferase 6 (GALNT6), which is upregulated in a great majority of breast cancers and encodes a glycosyltransferase responsible for initiating mucin-type O-glycosylation. Knockdown of GALNT6 by small interfering RNA significantly enhanced cell adhesion function and suppressed the growth of breast cancer cells. Western blot and immunostaining analyses indicated that wild-type GALNT6 protein could glycosylate and stabilize an oncoprotein mucin 1 (MUC1), which was upregulated with GALNT6 in breast cancer specimens. Furthermore, knockdown of GALNT6 or MUC1 led to similar morphologic changes of cancer cells accompanied by the increase of cell adhesion molecules beta-catenin and E-cadherin. Our findings implied that overexpression of GALNT6 might contribute to mammary carcinogenesis through aberrant glycosylation and stabilization of MUC1 and that screening of GALNT6 inhibitors would be valuable for the development of novel therapeutic modalities against breast cancer.


Ubiquitination and downregulation of BRCA1 by ubiquitin-conjugating enzyme E2T overexpression in human breast cancer cells.

Breast cancer is generated through a multistep genetic and epigenetic process including activations of oncogenes and inactivations of tumor suppressor genes. Here, we report a critical role of ubiquitin-conjugating enzyme E2T (UBE2T), an E2 ubiquitin-conjugating enzyme, in mammary carcinogenesis. Immunocytochemical staining and in vitro binding assay revealed that UBE2T interacted and colocalized with the BRCA1/BRCA1-associated RING domain protein (BARD1) complex. Knocking down of UBE2T expression with small interfering RNA drastically suppressed the growth of breast cancer cells. Interestingly, in vivo ubiquitination assay indicated BRCA1 to be polyubiquitinated by incubation with wild-type UBE2T protein, but not with C86A-UBE2T protein, an E2 activity-dead mutant, in which the 86th residue of cysteine was replaced with alanine. Furthermore, knocking down of UBE2T protein induced upregulation of BRCA1 protein in breast cancer cells, whereas its overexpression caused the decrease of the BRCA1 protein. Our data imply a critical role of UBE2T in development and/or progression of breast cancer through the interaction with and the regulation of the BRCA1/BARD1 complex.


Critical roles of T-LAK cell-originated protein kinase in cytokinesis.

We previously reported up-regulation of T-LAK cell-originated protein kinase (TOPK), a novel mitotic kinase, in the great majority of breast cancers. Here we report its critical roles in mitosis, especially in cytokinesis. We found that protein phosphatase 1 alpha (PP1alpha) inactivation by cyclin-dependent kinase 1 (CDK1)/cyclin B1 caused enhancement of autophosphorylation of TOPK and resulted in its activation at an early stage of mitosis. Then TOPK interacted with and phosphorylated p97, a member of the AAA+ family of ATPase proteins, through an interaction with p47 protein as an adaptor protein. Interestingly, knockdown of TOPK or p97 in breast cancer cells caused the mitotic failures in the abscission process. This mitotic failure could be rescued by additional exogenous introduction of wild-type TOPK protein, but not by that of its kinase-dead form. Our findings suggest that TOPK is indispensable for cancer cell cytokinesis throughout phosphorylation on p97.


Involvement of RQCD1 overexpression, a novel cancer-testis antigen, in the Akt pathway in breast cancer cells.

We here report identification and characterization of required for cell differentiation 1 homolog (RQCD1) as a potential therapeutic target for breast cancer. Gene-expression profiling analysis of breast cancer cells, semi-quantitative RT-PCR, Northern blotting and Western blotting confirmed RQCD1 to be frequently up-regulated in breast cancer specimens and breast cancer cell lines. On the other hand, its expression was very weak or hardly detectable in normal human tissues except testis, indicating this molecule to be a novel cancer-testis antigen. Treatment of breast cancer cell lines with siRNA targeting RQCD1 drastically suppressed cell proliferation. Concordantly, introduction of exogenous RQCD1 into HEK293 cells significantly enhanced cell growth, implying RQCD1 to have an oncogenic activity. Co-immunoprecipitation experiments and immunocytochemical staining revealed an interaction of RQCD1 protein with Grb10 interacting GYF protein 1 (GIGYF1) and 2 (GIGYF2) proteins, involved in regulation of Akt activation, in breast cancer cells. Interestingly, knockdown of either of RQCD1, GIGYF1 or GIGYF2 resulted in significant reduction of the phosphorylation of Akt at Ser 473 in breast cancer cell lines. Our findings suggest that RQCD1 is a potential molecular target for treatment of breast cancer.


Activation of an estrogen/estrogen receptor signaling by BIG3 through its inhibitory effect on nuclear transport of PHB2/REA in breast cancer.

Breast cancer is known to be a hormone-dependent disease, and estrogens through an interaction with estrogen receptor (ER) enhance the proliferative and metastatic activity of breast tumor cells. Here we show a critical role of transactivation of BIG3, brefeldin A-inhibited guanine nucleotide-exchange protein 3, in activation of the estrogen/ER signaling in breast cancer cells. Knocking-down of BIG3 expression with small-interfering RNA (siRNA) drastically suppressed the growth of breast cancer cells. Subsequent coimmunoprecipitation and immunoblotting assays revealed an interaction of BIG3 with prohibitin 2/repressor of estrogen receptor activity (PHB2/REA). When BIG3 was absent, stimulation of estradiol caused the translocation of PHB2/REA to the nucleus, enhanced the interaction of PHB2/REA and ERalpha, and resulted in suppression of the ERalpha transcriptional activity. On the other hand, when BIG3 was present, BIG3 trapped PHB2/REA in the cytoplasm and inhibited its nuclear translocation, and caused enhancement of ERalpha transcriptional activity. Our results imply that BIG3 overexpression is one of the important mechanisms causing the activation of the estrogen/ERalpha signaling pathway in the hormone-related growth of breast cancer cells.


Involvement of G-patch domain containing 2 overexpression in breast carcinogenesis.

Through analysis of the detailed genome-wide gene expression profiles of 81 breast tumors, we identified a novel gene, G-patch domain containing 2 (GPATCH2), that was overexpressed in the great majority of breast cancer cases. Treatment of breast cancer cells MCF-7 and T47D with siRNA against GPATCH2 effectively suppressed its expression, and resulted in the growth suppression of cancer cells, suggesting its essential role in breast cancer cell growth. We found an interaction of GPATCH2 protein with hPrp43, an RNA-dependent ATPase. Their interaction could significantly enhance the ATPase activity of hPrp43 and induce a growth-promoting effect on mammalian cells. Because northern blot analyses of normal human organs implied GPATCH2 to be a novel cancer/testis antigen, targeting GPATCH2 or inhibition of the interaction between GPATCH2 and hPrp43 could be a promising novel therapeutic strategy of breast cancer.


Radioimmunotherapy of solid tumors targeting a cell-surface protein, FZD10: therapeutic efficacy largely depends on radiosensitivity.

OBJECTIVE: Frizzled homolog 10 (FZD10) is expressed at high levels on the cell surface of almost all synovial sarcoma tissues, but is absent in most normal organs. In a previous study, yttrium-90 ((90)Y)-labeled anti-FZD10 antibody (MAb 92-13) showed considerable therapeutic efficacy in synovial sarcoma cell-bearing mice. The purpose of the present study was to elucidate the factors associated with this therapeutic efficacy of (90)Y-MAb 92-13. METHODS: FZD10 expression levels of SYO-1 (FZD10-overexpressing synovial sarcoma cell line) and DLD-1/FZD10 (FZD10-transfected DLD-1 cell) were determined by the cell binding assay, and their radiosensitivity was evaluated by incubation with (90)Y-MAb 92-13 in vitro. Biodistribution study of indium-111 ((111)In)-MAb 92-13 was performed in SYO-1 and DLD-1/FZD10 tumor-bearing mice. For therapeutic studies, SYO-1 and DLD-1/FZD10 tumor-bearing mice were treated with (90)Y-MAb 92-13 (100, 150, and 200 muCi), after which the change in tumor volume was measured. Immunohistochemical staining was performed on the excised tumor. RESULTS: Expression level of FZD10 on DLD-1/FZD10 was much greater than that on SYO-1. The accumulation of (111)In-MAb 92-13 was much higher in DLD-1/FZD10 tumor-bearing mice than in SYO-1 tumor-bearing mice (49.0 +/- 4.2 and 22.0 +/- 4.5% ID/g, respectively, at 48 h after administration). In SYO-1 tumor, substantial tumor size reduction was observed in all mice treated with (90)Y-MAb 92-13 (tumor volume decreased to less than 0.1 cm(3) at 11 days after treatment) and tumor regrowth was not observed in most of them. In contrast, only slow progression was observed in DLD-1/FZD10 tumor. When incubated with (90)Y-MAb 92-13, high radioactivity was needed to damage DLD-1/FZD10. Immunohistochemical study indicated apoptosis of SYO-1 tumor. CONCLUSIONS: The therapeutic efficacy of RIT seems to largely depend on the tumor radiosensitivity.


Orphan receptor tyrosine kinase ROR2 as a potential therapeutic target for osteosarcoma.

Osteosarcoma is the most prevalent bone malignant tumor in children and adolescents, and displays heterogeneous histology and high propensity for distant metastasis. Although adjuvant chemotherapy remarkably improved treatment outcome over the past few decades, prognosis for osteosarcoma patients with pulmonary metastasis is still unsatisfactory. To identify novel therapeutic targets for osteosarcoma, we investigated the gene expression profile of osteosarcomas by cDNA microarray analysis and found transactivation of receptor tyrosine kinase-like orphan receptor 2 (ROR2) expression in the majority of osteosarcoma samples. Treatment of osteosarcoma cell lines with siRNA against ROR2 significantly inhibited cell proliferation and migration. We also identified wingless-type MMTV integration site family, member 5B (WNT5B) as a putative ROR2 ligand and that the physiological interaction of WNT5B and ROR2 could enhance cell migration, indicating the possible roles of ROR2 and WNT5B in the metastatic property of osteosarcoma cells. Taken together, our findings revealed that the WNT5B/ROR2 signaling pathway is a promising therapeutic target for osteosarcoma.


Targeted serum glycoproteomics for the discovery of lung cancer-associated glycosylation disorders using lectin-coupled ProteinChip arrays.

To screen for glycoproteins showing aberrant sialylation patterns in sera of cancer patients and apply such information for biomarker identification, we performed SELDI-TOF MS analysis coupled with lectin-coupled ProteinChip arrays (Jacalin or SNA) using sera obtained from lung cancer patients and control individuals. Our approach consisted of three processes (i) removal of 14 abundant proteins in serum, (ii) enrichment of glycoproteins with lectin-coupled ProteinChip arrays, and (iii) SELDI-TOF MS analysis with acidic glycoprotein-compatible matrix. We identified 41 protein peaks showing significant differences (p<0.05) in the peak levels between the cancer and control groups using the Jacalin- and SNA-ProteinChips. Among them, we identified loss of Neu5Ac (alpha2,6) Gal/GalNAc structure in apolipoprotein C-III (apoC-III) in cancer patients through subsequent MALDI-QIT-TOF MS/MS. Furthermore, subsequent validation experiments using an additional set of 60 lung adenocarcinoma patients and 30 normal controls demonstrated that there is a higher frequency of serum apoC-III with loss of alpha2,6-linkage Neu5Ac residues in lung cancer patients compared to controls. Our results have demonstrated that lectin-coupled ProteinChip technology allows the high-throughput and specific recognition of cancer-associated aberrant glycosylations, and implied a possibility of its applicability to studies on other diseases.


Activation of the non-canonical Dvl-Rac1-JNK pathway by Frizzled homologue 10 in human synovial sarcoma.

We previously reported that Frizzled homologue 10 (FZD10), a member of the Wnt signal receptor family, was highly and specifically upregulated in synovial sarcoma and played critical roles in its cell survival and growth. We here report a possible molecular mechanism of the FZD10 signaling in synovial sarcoma cells. We found a significant enhancement of phosphorylation of the Dishevelled (Dvl)2/Dvl3 complex as well as activation of the Rac1-JNK cascade in synovial sarcoma cells in which FZD10 was overexpressed. Activation of the FZD10-Dvls-Rac1 pathway induced lamellipodia formation and enhanced anchorage-independent cell growth cells. FZD10 overexpression also caused the destruction of the actin cytoskeleton structure, probably through the downregulation of the RhoA activity. Our results have strongly implied that FZD10 transactivation causes the activation of the non-canonical Dvl-Rac1-JNK pathway and plays critical roles in the development/progression of synovial sarcomas.


Involvement of TMEM22 overexpression in the growth of renal cell carcinoma cells.

In order to clarify the molecular mechanism involved in renal carcinogenesis, and to identify molecular targets for development of novel treatments of renal cell carcinoma (RCC), we previously analyzed genome-wide gene expression profiles of clear-cell types of RCC by cDNA microarray. Among the transcativated genes, we herein focused on functional significance of TMEM22 (transmembrane protein 22), a transmembrane protein, in cell growth of RCC. Northern blot and semi-quantitative RT-PCR analyses confirmed up-regulation of TMEM22 in a great majority of RCC clinical samples and cell lines examined. Immunocytochemical analysis validated its localization at the plasma membrane. We found an interaction between TMEM22 and RAB37 (Ras-related protein Rab-37), which was also up-regulated in RCC cells. Interestingly, knockdown of either of TMEM22 or RAB37 expression by specific siRNA caused significant reduction of cancer cell growth. Our results imply that the TMEM22/RAB37 complex is likely to play a crucial role in growth of RCC and that inhibition of the TMEM22/RAB37 expression or their interaction should be novel therapeutic targets for RCC.


Inverse correlation of the up-regulation of FZD10 expression and the activation of beta-catenin in synchronous colorectal tumors.

We investigated the immunohistochemical expression patterns of Frizzled homolog 10 (FZD10), a cell-surface receptor for molecules in the Wnt pathway, in tissue samples derived from 104 patients with colorectal cancers (CRCs). There was no immunoreactivity for FZD10 in normal colonic mucosa, and only tumor cells in polyps and CRC tissues showed spotted immunostaining patterns in apical sides of the cytoplasm. In metastatic liver lesions, tumor cells showed cytoplasmic immunostaining similar to primary lesions, whereas normal liver parenchyma showed almost no immunostaining. Frequencies of FZD10-immunopositive cells in tumor tissues were significantly higher in CRCs than those in polyps (3.3 +/- 10.3% vs 20.5 +/- 31.7%, P = 0.0016), and almost equivalent with those in metastatic liver lesions (33.2 +/- 39.7% vs 26.4 +/- 33.4%, P = 0.133). Analyses of paired samples (polyps and CRCs, or CRCs and metastatic liver lesions from the same patient) suggested that a subset of CRCs possessed intrinsic genetic mechanisms causing the evolution of FZD10-positive clones during tumor progression, making FZD10 a promising candidate for molecular imaging and a target for therapy. To our surprise, cancer cells immunopositive for FZD10 showed significantly less nuclear accumulation of beta-catenin, compared to FZD10-immunonegative cancer cells, and there was a strong inverse correlation between nuclear immunostaining scores for beta-catenin expression and expression patterns of FZD10 (P = 0.0002), suggesting that FZD10 has a distinct role from other FZDs in canonical Wnt signal transduction.


Non-transmissible Sendai virus encoding granulocyte macrophage colony-stimulating factor is a novel and potent vector system for producing autologous tumor vaccines.

The recent clinical application of granulocyte macrophage colony-stimulating factor (GM-CSF)-transduced autologous tumor vaccines revealed substantial antitumor activity and valuable clinical results. However, for these vaccines to be optimally effective, the antitumor efficacies must be improved. Recently, Sendai virus (SeV) vectors, which are cytoplasmic RNA vectors, have emerged as safe vectors with high gene transduction. In the current study, the in vivo therapeutic antitumor efficacies of irradiated GM-CSF-transduced mouse renal cell carcinoma (RENCA) vaccine cells mediated by either fusion gene-deleted non-transmissible SeV encoding mouse GM-CSF (SeV/dF/G) or adenovirus (E1, E3 deleted serotype 5 adenovirus) encoding mouse GM-CSF (AdV/G) (respectively described as irRC/SeV/GM or irRC/AdV/GM) were compared in RENCA-bearing mice. The results showed that the antitumor effect was equivalent between irRC/SeV/GM and irRC/AdV/GM cells, even though the former produced less GM-CSF in vitro. The cell numbers of activated (CD80(+), CD86(+), CD80( (+) )CD86(+)) dendritic cells in lymph nodes from mice treated with irRC/AdV/GM or irRC/SeV/GM cells were increased significantly compared with those of mice treated with the respective controls, at both the earlier and later phases. In an in vitro cytotoxicity assay, splenocytes harvested from mice treated with both irRC/SeV/GM and irRC/AdV/GM cells showed tumor-specific responses against RENCA cells. The restimulated splenocytes harvested from mice treated with irRC/SeV/GM or irRC/AdV/GM cells produced significantly higher levels of interleukin-2, interleukin-4, and interferon-gamma compared with their respective controls (P < 0.05). Furthermore, vaccination with irRC/AdV/GM or irRC/SeV/GM cells induced significantly enhanced recruitment of the cytolytic effectors of CD107a(+)CD8(+) T cells and CD107a(+) natural killer cells into tumors compared with those induced by their respective controls (P < 0.05). Taken together, our results suggest that the SeV/dF/G vector is a potential candidate for the production of effective autologous GM-CSF-transduced tumor vaccines in clinical cancer immune gene therapy.


Involvement of elevated expression of multiple cell-cycle regulator, DTL/RAMP (denticleless/RA-regulated nuclear matrix associated protein), in the growth of breast cancer cells.

To investigate the detailed molecular mechanism of mammary carcinogenesis and discover novel therapeutic targets, we previously analysed gene expression profiles of breast cancers. We here report characterization of a significant role of DTL/RAMP (denticleless/RA-regulated nuclear matrix associated protein) in mammary carcinogenesis. Semiquantitative RT-PCR and northern blot analyses confirmed upregulation of DTL/RAMP in the majority of breast cancer cases and all of breast cancer cell lines examined. Immunocytochemical and western blot analyses using anti-DTL/RAMP polyclonal antibody revealed cell-cycle-dependent localization of endogenous DTL/RAMP protein in breast cancer cells; nuclear localization was observed in cells at interphase and the protein was concentrated at the contractile ring in cytokinesis process. The expression level of DTL/RAMP protein became highest at G(1)/S phases, whereas its phosphorylation level was enhanced during mitotic phase. Treatment of breast cancer cells, T47D and HBC4, with small-interfering RNAs against DTL/RAMP effectively suppressed its expression and caused accumulation of G(2)/M cells, resulting in growth inhibition of cancer cells. We further demonstrate the in vitro phosphorylation of DTL/RAMP through an interaction with the mitotic kinase, Aurora kinase-B (AURKB). Interestingly, depletion of AURKB expression with siRNA in breast cancer cells reduced the phosphorylation of DTL/RAMP and decreased the stability of DTL/RAMP protein. These findings imply important roles of DTL/RAMP in growth of breast cancer cells and suggest that DTL/RAMP might be a promising molecular target for treatment of breast cancer.


Over expression of hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and nuclear factor kappaB is putatively involved in acquired renal cyst formation and subsequent tumor transformation in patients with end stage renal failure.

We examined hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and nuclear factor-kappaB in acquired cystic disease of the kidney associated with renal cell carcinoma to elucidate the roles of these factors in cyst formation and subsequent tumor transformation. Immunohistochemical expression of hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB (active form) were examined in 20 normal kidney samples obtained from nephrectomy for localized renal cell carcinoma and 25 kidneys with acquired cystic disease associated renal cell carcinoma from 23 patients on dialysis. Only faint or weak immunostaining for hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB was observed in normal kidney tissues. In nontumor areas of the kidneys with acquired cystic disease expressions of these 3 proteins was up-regulated in tubular and cyst epithelial cells. Acquired cysts were classified into 3 types according to cyst epithelium morphology, namely flat, cuboidal and hyperplastic. Hyperplastic cysts were the predominant cysts expressing hypoxia-inducible protein 2 and hypoxia-inducible factor-1alpha. Although up-regulation of hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB was observed in renal cell carcinoma, positive hypoxia-inducible protein 2 immunostaining was detected predominantly in papillary renal cell carcinoma, while positive hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB immunostaining was prominent in clear cell renal cell carcinoma. Hypoxia-inducible protein 2, hypoxia-inducible factor-1alpha and phosphorylated nuclear factor-kappaB may be involved in a continuous process of the evolution of phenotypic expression from a simple cyst to epithelial hyperplasia and eventually to tumor.


CDC20, a potential cancer therapeutic target, is negatively regulated by p53.

The p53 protein inhibits malignant transformation through direct and indirect regulation of transcription of many genes related to cell cycle, apoptosis and cellular senescence. A number of genes induced by p53 have been well characterized, but biological significance of genes whose expression was suppressed by p53 is still largely undisclosed. To clarify the roles of p53-suppressive genes in carcinogenesis, we analysed two data sets of whole-genome expression profiles, one for cells in which wild-type p53 was exogenously introduced and the other for a large number of clinical cancer tissues. Here, we identified CDC20 that was frequently upregulated in many types of malignancies and remarkably suppressed by ectopic introduction of p53. CDC20 expression was suppressed by genotoxic stresses in p53- and p21-dependent manners through CDE-CHR elements in the CDC20 promoter. Furthermore, small interference RNA (siRNA)-mediated silencing of p53 induced CDC20 expression in normal human dermal fibroblast cells. As we expected, treatment of cancer cells with siRNA against CDC20 induced G(2)/M arrest and suppressed cell growth. Our results indicate that p53 inhibits tumor cell growth through the indirect regulation of CDC20 and that CDC20 might be a good potential therapeutic target for a broad spectrum of human cancer.