Reciprocal relationship between expression of hypoxia inducible factor 1α (HIF-1α) and the pro-apoptotic protein Bid in ex vivo colorectal cancer

Hypoxia inducible factor 1 (HIF-1) represses the transcription of pro-apoptotic bid in colorectal cancer cells in vitro. To assess the clinical relevance of this observation, HIF-1 alpha and Bid were assessed in serial sections of 39 human colorectal adenocarcinomas by immunohistochemistry. In high HIF-1 alpha nuclear-positive cell subpopulations, there was a significant reduction in Bid expression ( ANOVA, P=0.04). Given the role of Bid in drug-induced apoptosis, these data add impetus to strategies targeting HIF-1 for therapeutic gain.