Gene Expression profiles of colon from Hif-1α+/+, Hif-1αLSL/LSL

To investigate the detailed molecular mechanisms for the regulatory role of HIF-1α in colon, microarray gene expression analysis was performed on colon RNA isolated from 6- to 8-week-old Hif-1α+/+, Hif-1αLSL/LSL mice. Background & Aims: The progression and growth of solid tumors leads to a state where tumors outgrow their capacity for efficient oxygenation and nutrient uptake and an increase in tumor hypoxia. Tumor hypoxic response is mediated by hypoxia-inducible factor (HIF)-1a and HIF-2a. These transcription factors regulate a battery of genes that are critical for tumor oxygenation, tumor metabolism, and cell proliferation and survival. Therefore, inhibitors of HIF have been sought for as anti-neoplastic agents in several different kinds of cancers. Interestingly, in ischemic and inflammatory diseases of the intestine, activation of HIF-1a is beneficial, and can reduce intestinal inflammation. The efficacy of pharmacological agents that chronically activate HIF-1a are decreased due to the tumorigenic potential of HIF. However, recent advance in understanding HIF signaling have identified mechanisms, which could allow for isoform specific activators. Activation of HIF-2a increases colon carcinogenesis and progression in mouse models. However, the role of chronic HIF-1a activation is unclear in the progression in colon cancer. The present data demonstrates that activation of HIF-1a in epithelial cells does not increase colon carcinogens or progression in two mouse models of colon cancer, and provides the proof of principle that HIF-1a activation maybe safe as therapies for inflammatory bowel disease. Global gene expression profiling in colon RNAs isolated from 6- to 8-week-old Hif-1α+/+ (n=5, Shah 019) and Hif-1αLSL/LSL (n=5, Shah 020).