Hypoxia-inducible factor-1 (HIF-1) inhibitors from the last decade (2007 to 2016): A “structure–activity relationship” perspective

Tumor hypoxia is a common feature in most solid tumors and is associated with overexpression of the hypoxia response pathway. Overexpression of the hypoxia-inducible factor (HIF-1) protein leads to angiogenesis, metastasis, apoptosis resistance, and many other pro-tumorigenic responses in cancer development. HIF-1 is a promising target in cancer drug development to increase the patient's response to chemotherapy and radiotherapy as well as the survival rate of cancer patients. Since up to 1% of genes are hypoxia-sensitive, a target-specific HIF-1 inhibitor may be a better clinical candidate in cancer drug discovery. Though no HIF-1 inhibitor is clinically available to date, a lot of effort has been applied during the last decade in search of potent HIF-1 inhibitors. In this review, we will summarize the structure–activity relationship of ten different chemotypes reported to be HIF-1 inhibitors in the last decade (2007–2016), their mechanisms of action for HIF-1 inhibition, progress in the way of target-specific inhibitors, and problems associated with current inhibitors. It is anticipated that the results of these research on the medicinal chemistry of HIF-1 inhibitors will provide decent information in the design and development of future inhibitors.