Abstract : The first aim of our study was to evaluate the effect of the association between bicalutamide, an androgen receptor inhibitor, and ionizing radiation in three prostate cancer cell lines. The second aim was to examine a possible a correlation between the expression of miR-210 or miR-373, the tolerance to hypoxia tolerance and the responses to radiation.We found that bicalutamide produced cytostatic and cytotoxic effects in the androgen receptor- positive LNCaP cell line. The androgen receptor-negative DU145 and PC3 cell lines were more resistant to bicalutamide. However, these cell lines were affected by high bicalutamide concentration with the same endpoints as for LNCaP cells. The inhibition of proliferation by bicalutamide was associated with G1 cell cycle phase arrest, increased expression of p27KIP1 protein, and decreased expression of HER2 protein. Last but not least, bicalutamide elicited a marked radioprotective effect in LNCaP cells when associated with concomitant irradiation. This result suggests that bicalutamide and radiotherapy should not be delivered in close temporal proximity, especially in case of hypofractionated radiotherapy protocols.Hypoxia is a well known radioresistance factor in tumors and is associated with a bad prognosis in prostate cancer. In this study, we found that hypoxia promotes the expression of HIF-1α, CA9, VEGF and miR-210 but not miR-373 in prostate cancer cell lines irrespective of their androgen receptor status.Our findings suggest that miR-210 expression is correlated with resistance to hypoxia and could be used as a prognostic marker in prostate cancer. Conversely, miR-210 inhibition did not impact the radiation susceptibility of PC3 prostate cancer cell line under hypoxia.