Lastly, when DSS was given together with azoxymethane to induce tumorigenesis in the colon, we found that hMRP8 <i>Hif-1a</i> KO mice exhibited comparable levels of colorectal tumors to those of WT mice, indicating that HIF-1α in myeloid cells is dispensable for tumorigenesis.
Here, we report that The Drosophila Eyes Absent Homologue 1 (EYA1), which is overexpressed in colorectal tumor cells, can promote colorectal tumor angiogenesis by coordinating with the hypoxia-inducible factor 1 (HIF-1α) to increase the expression of VEGF-A.
We found that the HIF-1α gene expression, HIF-1α protein concentration, and IHC expression of HIF-1α, GLUT-1, Ki-67, and Bcl-2 were not systematically affected by either the fixation or freezing delay of the tissue, the perioperative ischemia time, or the total ischemia time (perioperative ischemia+delay of fixation or freezing) in colorectal tumors.
iNOS and HIF-1alpha expression in colorectal carcinoma was significantly higher than in non-neoplasm colorectal mucosa (c2 = 43.166, P < 0.01; c2 = 10.4278, P < 0.01); eNOS expression in colorectal carcinoma was significantly lower than in non-neoplasm colorectal mucosa (c2 = 11.354, P < 0.01).
Direct transcriptional up-regulation of cyclooxygenase-2 by hypoxia-inducible factor (HIF)-1 promotes colorectal tumor cell survival and enhances HIF-1 transcriptional activity during hypoxia.