Abstract 825: Cetixumab enhanced apoptosis effects of radiation on human prostate cancer cell line PC-3

Abstract

Abstract Prostate cancer is a leading cause of cancer death in men in developed countries. Radiotherapy is the main treatment to prostate cancer. Dose escalation of irradiation with image guide rasdiotherapy and intensity modulated radiotherapy were used with more and more evidences in prostate cancer patients and bring in longer PSA-free survival time. Although the evolution of radiation techniques bring better outcomes, but modern modalities were not avaliable in non-western world. Radiation enhancement is still an improtant issus in prostate cancer in non-western world, especially in androgen independnt prostate cancer. The epidermal growth factor receptor (EGFR) network has rich targets for prostate cancer killing. The chimeric monoclonal antibody Cetuximab (IMC-A12, Erbitux®) binds to EGFR and prevents its intracellular signaling. Currently, it is approved for treatment of wild-type KRAS colon and head and neck cancer. The effect and mechanisms of Erbitux and radiotherapy are still not clear. In this study, we evaluated the effects of combining the EGFR inhibition and radiation on PC-3 prostate cancer cells. PC-3 cells were treated with various doses(1,2.5,5 and 10 ug/ml) of anti-EGFR antibody (CETUXIMAB) and irradiation(5, 7.5 Gy). The results revealed that 5 and 10 ug/ml of CETUXIMAB significnatly reduced the colony formation. The cell cycle analysis revealed that CETUXIMAB significnatly enhanced the radiation induced G2/M phase arrest and subG1 peak increasing. The Hoechst staining and DNA laddering analysis revealed radiation and CETUXIMAB combined use will induced more apoptotic bodies or DNA fragmentation than radiation alone use. By using a apaptosis protein array, we found that several apaptosis related protein (Catalase, cIAP-1, Clusterin, Fas, HIF-1α, HSP27, HSP60, HSP70, SMAC and Survivin) were significantly downregulated in radiation and CETUXIMAB combined group. Taken together, our results demonstrated that Erbitux enhanced apoptosis effects of radiation on PC-3. Citation Format: Chia-lun Chang, Szu-Yuan Wu. Cetixumab enhanced apoptosis effects of radiation on human prostate cancer cell line PC-3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 825. doi:10.1158/1538-7445.AM2017-825