R. Radhakrishnam Ruddarraju, Yuya Komatani, Yasuaki Tokodai and Satoshi Ichikawa : Concise Total Synthesis of Sandramycin and Its Analogues via Cyclodimerization Using Mitsunobu Reaction, The Journal of Organic Chemistry, 90, 29, 10550-10554, 2025.
Kengo Tatsumi, Shun Kitahata, Yuya Komatani, Akira Katsuyama, Fumika Yakushiji and Satoshi Ichikawa : Modulation of proteasome subunit selectivity of syringolins, Bioorganic & Medicinal Chemistry, 106, 117733, 2024.
(Summary)
Development of selective or dual proteasome subunit inhibitors based on syringolin B as a scaffold is described. We focused our efforts on a structure-activity relationship study of inhibitors with various substituents at the 3-position of the macrolactam moiety of syringolin B analogue to evaluate whether this would be sufficient to confer subunit selectivity by using sets of analogues with hydrophobic, basic and acidic substituents, which were designed to target Met45, Glu53 and Arg45 embedded in the S1 subsite, respectively. The structure-activity relationship study using systematic analogues provided insight into the origin of the subunit-selective inhibitory activity. This strategy would be sufficient to confer subunit selectivity regarding β5 and β2 subunits.
Keita Kojima, Hiroaki Konishi, Kyoka Momosaki, Yuya Komatani, Akira Katsuyama, Koji Nakagawa, Kayoko Kanamitsu, Fumika Yakushiji, Mikihiro Fujiya and Satoshi Ichikawa : Synthesis and biological evaluation of echinomycin analogues as potential colon cancer agent, Scientific Reports, 14, 1, 7628, 2024.
(Summary)
Colorectal cancer is the third most commonly diagnosed cancer and the second leading cause of cancer-related death, thus a novel chemotherapeutic agent for colon cancer therapy is needed. In this study, analogues of echinomycin, a cyclic peptide natural product with potent toxicity to several human cancer cell lines, were synthesized, and their biological activities against human colon cancer cells were investigated. Analogue 3 as well as 1 inhibit HIF-1α-mediated transcription. Notably, transcriptome analysis indicated that the cell cycle and its regulation were involved in the effects on cells treated with 3. Analogue 3 exhibited superior in vivo efficacy to echinomycin without significant toxicity in mouse xenograft model. The low dose of 3 needed to be efficacious in vivo is also noteworthy and our data suggest that 3 is an attractive and potentially novel agent for the treatment of colon cancer.
Yuya Komatani, Kyoka Momosaki, Akira Katsuyama, Kazuki Yamamoto, Rintaro Kaguchi and Satoshi Ichikawa : Solid-Phase Total Synthesis of Sandramycin and Its Analogues, Organic Letters, 25, 3, 543-548, 2023.
(Summary)
Solid-phase total synthesis of sandramycin (1), which is a C2-symmetric cyclic decadepsipeptide natural product, and its analogues is described. On-resin ester formation and [5+5] peptide coupling allowed the preparation of a range of desymmetrized analogues. An amino acid residue that would not hamper the biological activity of 1 was successfully identified, and probe molecules and dimeric analogues were prepared on the basis of the result of the structure-activity relationship study.