Figure 3.

Proposed mechanisms by which HIF-1 mediates resistance to anticancer therapy. HIF-1 may mediate the resistance to chemo/radiotherapy by inducing drug efflux transporters, such as MDR1/P-gp, repairing DNA damage, reprogramming tumor metabolism, interrupting programmed cell death, including apoptosis, and augmenting autophagy. Blue arrows indicate stimulation, while blocked red arrows indicate inhibition. HIF-1—hypoxia-inducible factor-1; MDR1—multidrug resistance 1 protein; P-gp—P-glycoprotein.