Abstract 3549: Special characteristics of betel-nuts related head and neck squamous cell carcinoma (HNSCC) in Taiwan
Authors: Chen Jo-Pai , Chen Ling-Yu , Kuo Sung-Hsin , Hong Ruey-Long 
Published: August 2015

Purpose: The treatments of HNSCC in Taiwan is still very challenging and might be related to betel nuts use. Betel nuts chewing might contribute to (1)strong inflammation and angiogenesis; (2)strong invasion and queer metastatic sites; (3)easy recurrence or metastasis, usually accompanied with hypercalcemia; (4)not so good response to chemotherapy and epidermal growth factor receptor inhibitors;(5)relatively good response to vascular endothelial growth factor inhibitors combined with chemotherapy; (6)difficult wound healing and repair. We try to prove the difference of betel nuts-related HNSCC cell lines in several aspects reflecting clinical characteristics of HNSCC in Taiwan and design effective treatment combinations for future clinical trials and treatment decisions.

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(several chemotherapies and target agents); (2) synergistic effect of some target therapies and irradiation with MTT assay, colony formation assay, flow cytometry, and western blot assay. TW2.6 had already been proved to possess defective p53, p16 loss, and increased Bcl2.

Results:

The MTT assay showed betel-nuts related TW2.6 was resistant to tradiational chemotherapies, radiation, EGFR inhibition, or anti-angiogenesis alone. TW2.6 was sensitive to high dose docetaxel and dual PI3K/mTOR inhibitor, BEZ235. Western blotting showed (1) p-AKT level was prominent in TW2.6 and correlated to BEZ235 response; (2) High PDL1 and VEGF levels in TW2.6 may confer to immunotherapy or anti-angiogenesis response; (3) Almost p16 loss in all cell lines; (4) Prominent Gli-1 expression in HPV-related FaDu and SCC25. SCC25, SAS, KB, and Cal27 showed good chemosensitivity. Well-differentiated cell lines(SCC4, 9, 15, 25), Cal27, and FaDu responded well to EGFR inhibitors. The cell viability assay showed that volasertib(polo like kinase inhibitor) did not decrease TW2.6 proliferation significantly. But clonogenic survival showed that combination of volasertib and radiation significantly enhanced radiation-induced death. The flow cytometry revealed that Plk1 inhibition by volasertib and radiation resulted in a significant G2/M cell cycle arrest. Western blotting also showed volasertib and radiation combination increased cyclin B levels and induced apoptosis.

Conclusions:

These findings suggested that TW2.6 might reflect treatment refractoriness of betel-nuts related HNSCC in Taiwan. PI3K/mTOR dual inhibition, anti-angiogenesis with chemotherapy, and immunotherapy are important strategies in our experiments. Besides, polo like kinase inhibition is a good radiosensitizer for TW2.6. Further animal studies, genetic studies, and array analysis will further clarify these points of views. Mesenchymal(like Axl) and invasion(such as c-MET) pathways will also be considered as future targets.

Note: This abstract was not presented at the meeting.

Citation Format: Jo-Pai Chen, Ling-Yu Chen, Sung-Hsin Kuo, Ruey-Long Hong. Special characteristics of betel-nuts related head and neck squamous cell carcinoma (HNSCC) in Taiwan. [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 3549. doi:10.1158/1538-7445.AM2015-3549