ARNT and head and neck squamous cell carcinoma: Additionally, we observed that an siRNA knockdown of HIF‐1α and HIF‐1β reduced the protein levels of BNIP3, demonstrating the important interaction between HIF and autophagy regulation Furthermore, we also found that autophagy acts as a protective mechanism in HPV‐negative HNSCC cells post‐irradiation under mild hypoxia, and where targeting BECLIN1 or BNIP3/3L using siRNA can radiosensitize the cells to x‐rays.