Carbonic anhydrase III is a new target of HIF1 alpha in prostate cancer model

Abstract

Carbonic Anhydrase III (CAIII) belongs to a member of the alpha Carbonic Anhydrase (CA) family. Although some CA members are strongly up-regulated by HIF1-alpha, it is not known about the transcriptional regulation of CAIII in prostate cancer cells, PCa. Therefore, we aimed to identify regulatory regions important for the regulation of CAIII gene under hypoxic conditions in human prostate cancer cells (PC3). The present study, for the first time, demonstrated that the chemically mimicked hypoxic condition led to the induced CAIII mRNA and protein expression in prostate cancer cells. Transcriptional regulation of CAIII was investigated by transient transfection assay that indicates that the most active promoter activity was in the region of P2 -699/+86. Hypoxic condition also upregulates the basal activity of for P1; -941/+86 and P2; -699/+86 constructs containing putative Hypoxia Response Element (HRE) region located in -268/-252. EMSA analysis of HRE located in -268/-252 bases, showed one DNA-protein binding complexes. Competition assays indicated this complex is resulted from HIF1 alpha interactions. In addition, site-directed mutagenesis of potential HIF1 alpha binding sites diminished a DNA-protein complex. These findings suggest that CAIII is a hypoxia-regulated gene and valuable for targeting of prostate cancer tumors in hypoxic condition.