Abstract 4639:SLC7A11expression confers cancer stem-like properties in small cell lung cancer cells

Small Cell Lung Cancer (SCLC) which accounts for 15 % of primary lung cancers is known to grow fast and metastasize easily to whole body at early stages. However, the standard care of SCLC has not been changed for over 10 years and effective treatment remains to be developed. System xc(-) comprises xCT (SLC7A11) and CD98hc subunits and is a major plasma membrane antiporter responsible for the cellular uptake of cystine in exchange for intracellular glutamate. Recently, we studied the impact of xCT inhibitor sulfasalazine (SSZ) in various cancers and found that SCLC cells manifest low level of xCT and are highly sensitive to SSZ treatment compared with non-small cell lines. Furthermore, we found that xCT expression in SCLC cells is regulated by the cellular density and the tumorsphere culture which is known to enhance the cancer stem cell properties also enhances the xCT expression in these cells. To examine the functional relevance of xCT expression to cancer stem-like properties in SCLC cells, we established the stably xCT-expressing SBC-5 cells (SBC5-xCT). Similar to other SCLC cell lines, parental SBC5 cells were not able to proliferate from single-cell level, however, SBC5-xCT cells were found to possess an ability to proliferate from single-cell level. Furthermore, SBC5-xCT cells manifested higher resistance to an anticancer agent cisplatin and higher ability of tumor-initiation than parental SBC5 cells. Our findings establish a new functional role for xCT in the promotion of cancer stem-like properties in SCLC cells. Citation Format: Shohei Kamenori, Kentaro Suina, Juntaro Yamasaki, Subaru Shintani, Yuji Otsuki, Yuki Hirata, Shogo Okazaki, Kenji Tsuchihashi, Oltea Sampetrean, Yoichiro Mitsuishi, Fumiyuki Takahashi, Kazuhisa Takahashi, Hideyuki Saya, Osamu Nagano. SLC7A11 expression confers cancer stem-like properties in small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4639.