Abstract 3616: Development of a Sox2 targeting therapy for the treatment of lung squamous cell carcinoma

Abstract Despite the recent development of several effective molecular targeted agents, lung cancer is the most common cause of cancer related deaths worldwide. Recently, molecular targeted therapies for pulmonary adenocarcinoma with mutant EGFR or ALK fusions have reduced non-tumor toxicity and have extended patient survival time compared to conventional chemotherapies. However, the development of molecular targeting drugs for NSCLC has made apparent the fact that histology is an important factor and molecularly targeted therapies have been more effective in pulmonary adenocarcinoma than in lung squamous cell carcinoma. Therefore, specific therapies that target lung squamous cell carcinoma are desperately needed. Sox2 is a master pluripotency controller that was recently identified as a novel major oncogene, recurrently amplified and activated in lung squamous cell carcinoma. Immunohistochemistry shows that Sox2 expression is seen in approximately 55% of human pulmonary adenocarcinoma sections. On the other hand Sox2 expression is detected in more than 90% of lung squamous cell carcinoma sections. Inhibition of Sox2 by siRNA suppresses cell viability and colony formation of Sox2 expressing EBC2 and LK2 lung squamous cell carcinoma cells. Moreover, Sox2 siRNA inhibits lung squamous cell carcinoma growth in vivo in a xenograft mouse model derived from EBC2 cells. Flowcytometric analysis demonstrated that Annexin V positive and PI negative cell populations were not changed 48 hours after Sox2 silencing in EBC2 lung squamous cell carcinoma cells. Microarray analysis demonstrated that the expression of several cell cycle related genes were changed after Sox2 silencing in Sox2 expressing lung squamous cell carcinoma cells. Cell cycle analysis showed that Sox2 silencing significantly increased the G1 population in the cells. These results indicate that Sox2 silencing might produce an antitumor effect via G1 cell cycle arrest. Citation Format: Naomasa Ishida, Takuya Fukazawa, Munenori Takaoka, Tomoki Yamatsuji, Ichiro Morita, Minoru Haisa, Nagio Takaoka, Yoshio Naomoto. Development of a Sox2 targeting therapy for the treatment of lung squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3616. doi:10.1158/1538-7445.AM2015-3616