Research progress of anti-tumor components of traditional Chinese medicine inhibiting the expression of HIF-1α

Hypoxia is one of the most significant characteristics of solid tumors. Hypoxia microenvironment can lead to the overexpression of hypoxia inducible factor-1α (HIF-1α). As the most critical transcription factor in the hypoxia response, HIF-1α activates downstream gene expression resulting in abnormal tumor cell proliferation, tumor angiogenesis, unusual energy metabolism, increased drug resistance, invasion, and metastasis. Down-regulation of HIF-1α expression is considered as a promising approach for the treatment of solid tumors, whereas the clinical efficacy of most existing HIF-1α inhibitors is restricted in low efficacy and high toxicity. Therefore, it is particularly important to develop powerful and safe novel drugs against the overexpression of HIF-1α. In recent years, numbers of studies have proved that a variety of chemical components of traditional Chinese medicine can directly or indirectly inhibit the activation of HIF-1α, which has a broad prospect in the fight against hypoxia-induced tumor progression. In this review, we summarized various anti-tumor active components of traditional Chinese medicines responsible for inhibiting the expression of HIF-1α in last ten years and analyzed the corresponding mechanism, with a view to further research as a reference.