Abstract 59: Novel mechanisms-guided treatments for betel nuts-related head and neck squamous cell carcinoma in Taiwan

Abstract

Abstract Background: Betel nuts-related HNSCCs in Taiwan will cause (1) strong inflammation, invasion, and angiogenesis; (2) poor response to chemotherapy, radiation, and epidermal growth factor receptor inhibitors. Methods: HNSCC cell lines (SCC4, SCC9, SCC15, SCC25, FaDu, KB, Cal27, SAS, and TW2.6, betel nuts-related) were used to evaluate (1) the in vitro drug sensitivity; (2) synergistic effects of different treatment combinations with MTT assay, colony formation, flow cytometry, and Western blotting; (3) invasion capacity by wound healing. TW2.6 had already been proved to possess defective p53, p16 loss, and increased Bcl2. Results: TW2.6 was resistant to chemotherapies, radiation, and EGFR inhibition, but sensitive to PI3K/mTOR dual inhibition (BEZ235), CDK4/6 inhibitor (palbociclib), Bcl2 inhibitor (ABT-199), WEE1 inhibitor(AZD1775), FGFR inhibitor(BGJ398), ALK/IGF-1R inhibitor (ceritinib), and eribulin. Polo-like kinase inhibitor (volasertib) with radiation, resulting in G2/M arrest in flow-cytometry and increased cyclin B levels in Western blotting, caused TW2.6 apoptosis. Nintedanib and regorafenib (VEGFR/PDGFR/FGFR inhibitor) and foretinib (VEGFR/c-MET/Axl inhibitor) would suppress HUVEC, block invasion capacity of TW2.6, inhibit TW2.6 growth, and resensitize TW2.6 to docetaxel, afatinib, and volasertib. Western blotting showed (1) mesenchymal markers (Slug, Snail, Axl, Twist, Vimentin, Claudin-1), PI3K/Akt/mTOR signaling (p-Akt and p70S6K), and BMI-1 dropped after nintedanib, regorafenib, and foretinib; (2) PDL1 drop after foretinib use. BYL719, ABT-199, and ceritinib also sensitize TW2,6 to docetaxel. Astragalus polysaccharides, minimally cytotoxic on TW2.6, could inhibit tumor migration, suppress epithelial-mesenchymal transformation and PI3K/AKT/mTOR pathway, and induce PDL1 drop. APS re-sensitizes TW2.6 to afatinib and volasertib. Olaparib (PARP inhibitor) also had poor effect on TW2.6, but volasertib, AZD1775, and foretinib could reverse olaparib resistance. Conclusions: TW2.6 might reflect treatment refractoriness of betel nuts-related HNSCC in Taiwan. Several novel mechanisms-guided treatment combinations should be tried in the future. Citation Format: Jo-Pai Chen, Jui-Ying Chang, Ruey-Long Hong. Novel mechanisms-guided treatments for betel nuts-related head and neck squamous cell carcinoma in Taiwan [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 59.