The present disclosure relates to inhibitors of mitochondrialfunction. Methods of treating hypoxic cancer cells using anti-angiogenicagents and mitochondrial biogenesis inhibitors are disclosed.Tetracyclines, such as doxycycline, may serve as mitochondrial biogenesisinhibitors. Also described are methods of sensitizing hypoxic cancercells to one or more chemotherapies by administering a mitochondrialbiogenesis inhibitor with the chemotherapy.