HIF-1: Using Two Hands to Flip the Angiogenic Switch

Cancer and Metastasis Reviews - Tập 19 - Trang 59-65 - 2000
Gregg L. Semenza1
1Institute of Genetic Medicine, Departments of Pediatrics and Medicine, The Johns Hopkins University School of Medicine, Baltimore, USA

Tóm tắt

In brain, breast, and other common human tumors there is a correlation between expression of the transcriptional activator hypoxia-inducible factor 1 (HIF-1) and tumor grade and vascularization. HIF-1 stimulates angiogenesis by activating transcription of the gene encoding vascular endothelial growth factor (VEGF). HIF-1 is a heterodimer consisting of a constitutively-expressed HIF-1β subunit and an O2– and growth factor-regulated HIF-1α subunit. Recent studies have demonstrated that HIF-1α expression is increased in tumor relative to normal tissue by two mechanisms. First, decreased intratumoral O2 concentrations provide a physiological stimulus. Second, genetic alterations that activate oncogene products or inactivate tumor suppressor gene products increase HIF-1α expression and/or HIF-1 transcriptional activity independent of the O2 concentration. Taken together, these recent data suggest that increased HIF-1 activity provides a molecular basis for VEGF-induced angiogenesis and other adaptations of cancer cells to hypoxia that are critical for establishment of a primary tumor and its progression to the lethal phenotype.

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