Abstract 5126: Novel indolizino[8,7-b]indole hybrids with potent activity against small cell lung cancer

Abstract

Abstract Small cell lung cancer (SCLC) is an aggressive type of lung cancer and accounts for 10% to 15% of all lung cancer cases. The malignancy has a greater tendency to be widely disseminated by the time of diagnosis as well as to develop early resistance to conventional treatments, a cure is difficult to achieve. The current standard therapy for SCLC treatment, either with monotherapy (platinum based drugs) or combination therapy (e.g., cisplatin with irinotecan or topotecan), was shown to cause serious side effects and inevitably evoke drug resistance in a short time period. We have recently synthesized a series of novel bis(hydroxymethyl)indolizino[8,7-b]indole hybrids by fusing β-carboline and bis(hydroxymethyl)pyrrole moieties for antitumor evaluation. These hybrid molecules displayed diverse mechanisms of action involving topoisomerase II (Topo II) inhibition and induction of DNA cross-linking. Our results also showed that they significantly inhibited the cell growth of various human tumor cell lines. Of the tested tumor cell lines, the SCLC cells (H526 and H211) were the most susceptible to compounds BO-2239 and BO-2329. These hybrids induced cell cycle arrest at the G2/M phase and triggered tumor cell apoptotic death. Intriguingly, the substituent at N11 (H or Me) played a critical role in modulating Topo II inhibition and DNA cross-linking. Compared to the compounds with N11-Me group, derivatives having N11-H group profoundly increased Topo II inhibition activity but reduced DNA cross-linking activity. Among these hybrids, BO-2239 (with N11-H) was as potent as irinotecan, but more effective than cisplatin, in nude mice bearing SCLC H526 xenografts. Accordingly, hybrid BO-2239 may be further developed as a potential agent for the treatment of SCLC. Citation Format: Sue-Ming Chang, Ming-Hsi Wu, Hima Bindu Pidugu, Tsann-Long Su, Te-Chang Lee. Novel indolizino[8,7-b]indole hybrids with potent activity against small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5126. doi:10.1158/1538-7445.AM2017-5126