Abstract 1170: EphA3 maintains radioresistance in head and neck cancers

Radiotherapy is a well-established therapeutic modality used in treatment of many cancers. However, radioresistance remains a serious obstacle to successful treatment. Radioresistance can cause local recurrence and distant metastases in some patients after treatment by radiation. Thus, special emphasis has been given to the discovery of effective radiosensitizers. EphA3 receptors functions contribute to tumor development, modulating cell-cell adhesion, invasion, neo-angiogenesis, tumor growth and metastasis. However, the role of EphA3 in radioresistance remains to be elucidated. Here, we established the stable radioresistant head and neck cancer cell line (AMC HN3R cell line) and identified that EphA3 was overexpressed predominantly in the AMC HN3R cancer cell line through DNA microarray, real time PCR and Western blotting. Additionally, we identified that EphA3 was overexpressed in recurred laryngeal cancer specimen after radiation therapy. And we found that EphA3 mediated the tumor invasiveness and migration and EMT (epithelial mesenchymal transition) related protein expression in AMC HN3R cancer cell line. To investigate the role of EphA3 in modulating the radiosensitivity, we observed the change of survival fraction after transfection EphA3 siRNA. And we found that inhibition of EphA3 enhances radiosensitivity in AMC HN 3R cell line. In conclusion, these results suggest that EphA3 is overexpressed in radioresistant head and neck cancer and can play a crucial role in development radioresistance in head and neck cancers through regulation of EMT pathway. Citation Format: Myung Woul Han, Song Hee Kim, Hyo Won Chang, Hae Yun Nam, Myungjin Lee, Gui Chul Kim, Yoon sun Lee, Mi Ra Kim. EphA3 maintains radioresistance in head and neck cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1170.