LAUSR

Small cell lung cancer (SCLC) is a highly aggressive disease with median survival of RNA sequencing was performed using the established cell lines to discover novel therapeutic targets associated with the resistance to topoisomerase inhibitors. We found that whenever the drug efflux protein ATP-binding cassette transporter B1 (ABCB1) was associated the with resistance of VP-16, ATP-binding cassette super-family G member 2 (ABCG2) was associated with the resistance of SN-38. The silencing of ABCG2 or ABCB1 in every resistant cell line, could induce synergistic apoptosis of every cell line. Elacridar and tariquidar which are glycoprotein inhibitors, recovered the sensitivity of SN38 or VP-16 in every resistant line, increased expression of signaling proteins associated with DNA damage and cell-cycle checkpoints, and promoted G2/M arrest and apoptosis. Furthermore, we are going to analyze the expressions of ABCG2 and ABCB1 in serum before and after the treatment of VP-16 or CPT-11. These results suggested the glycoprotein inhibitors, which phase I study is ongoing, could be a promising therapeutic strategy for the purpose of preventing the resistance of topoisomerase inhibitors in SCLCs. Citation Format: Rintaro Noro, Miwako Omori, Aya Fukuizumi, kuniko Matsuda, Mariko Hirao, Satoshi Takahashi, Natsuki Takano, Shinji Nakamichi, Teppei Sugano, Akihiko Miyanaga, Yuji Minegishi, Masahiro Seike, Kaoru Kubota, Akihiko Gemma. The glycoprotein inhibitors overcome the resistance of the topoisomerase inhibitors in small cell lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3068.