Abstract A2-32: Identification of withaferin A as a novel cancer stem cell inhibitor to overcome drug resistance in non-small cell lung carcinoma

Cancer stem cell (CSC) theory has drawn much attention, with evidence supporting the contribution of stem cells to tumor initiation, relapse, and therapy resistance. In this study, we focus on screening drugs that target CSCs to improve the current treatment outcome and overcome drug resistance in patients with lung cancer. We used publicly available embryonic stem cell and CSC-associated gene signatures to query the Connectivity Map (CMap) for potential drugs that can, at least in part, reverse the gene expression profile of CSCs. High scores were noted for several phenothiazine-like antipsychotic drugs, including trifluoperazine and perphenazine. The combination of gemcitabine with either trifluoperazine or perphenazine shows synergistic effects in anti-NSCLC cells. By using L1000 and CMap analysis, we identified withaferin A (WA) as a potential drug, which shares similar gene expression patterns to trifluoperazine or perphenazine combine with gemcitabine and to reverse differential gene expression of stem-like cell vs. differential cell. Further experiments demonstrated that WA significantly suppressed cancer stemness associated phenotypes, shown by decreasing side population and tumor spheroid formation. Furthermore, WA was accompanied by down-regulation of JAK2/STAT3 signaling pathway. The combination of WA and cisplatin significantly reduced the number of cancer spheroids and attenuated the proportion of ALDH + cell population in CL97 lung spheroids, which was resistant to cisplatin treatment alone. In vivo study also demonstrated the anti-tumor effect of WA treatment. In conclusion, WA was identified as a potential anti-cancer stem cell inhibitor, which could also inhibit tumorigenesis and overcome cisplatin resistance in lung cancer. Citation Format: Tai-shan Cheng, Yu-Chen Tsai, Alexander T. H. Wu, Peter M. H. Chang, Wei-Hsiang Hsu, Jin-Mei Lai, Chi-Ying Huang. Identification of withaferin A as a novel cancer stem cell inhibitor to overcome drug resistance in non-small cell lung carcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A2-32.