The Experimental Research Of YC-1 On HIF-1 Transcriptional Activity, Proliferation And Apoptosis In Hypoxic Human Pancreatic Cancer PC-3 Cells

BACKROUND & AIM: Hypoxic microenvironment is a typical characteristic for most malignancy, including human pancreatic cancer. Tumor tissues have developed a series of essential mechanisms to cope with such a stress. Hypoxia inducible factor-1 (HIF-1) is an essential component in changing the transcriptional repertoire of tissues as oxygen levels drop. Given the central role that HIF-1-driven transcription factor activity has in compensating for loss of oxygen, it is clear that modulation of HIF-1 activity could be a potent mechanism for treating a wide rage of hypoxia-related pathologies. Here, we made HIF-1 as the controlling target, using a substance named YC-1, to investigate the effects of YC-1 on HIF-1-driven transcription activity, cell proliferation and apoptosis in hypoxic human pancreatic cancer cells.METHODS: The human pancreatic cancer PC-3 cells were incubated under normoxia or hypoxic conditions established by using CoCl2 in culture media placed in hypoxic incubator filled with 95% N2. YC-1, a guanylate cyclase activator, was added to the media with different concentrations. HIF-1αprotein expression in PC-3 cells was detected by immunocytochemical staining as well as Western blotting. Semi-quantitative RT-PCR was used to determine the mRNA expression of HIF-1α, vascular endothelial growth factor (VEGF) and glucose phosphate isomerase (GPI). MTT assay and flow cytometry were used to detect proliferation and apoptosis of PC-3 cells.RESULTS: PC-3 hypoxic cells expressed a higher level of HIF-αprotein in nucleus, with weak cytoplastic HIF-αexpression in a few cells, compared with the normoxic cells. When the dose of YC-1 was at 100μmol/L, the expression location of HIF-αshifted from nucleus to cytoplasm. Western blotting revealed that YC-1 reduced the level of HIF-1αprotein expression, and the inhibitory effect was dose-dependent. Moreover, YC-1 inhibited mRNA expression levels of VEGF and GPI in a dose-dependent manner in hypoxic cells. YC-1 inhibited proliferation and induced apoptosis of hypoxic PC-3 cells in a dose-dependent manner.CONCLUSION: YC-1 inhibits HIF-1αexpression in hypoxic pancreatic cancer cells, which is accompanied by translocation of HIF-1αfrom nucleus to cytoplasm, decreased mRNA expression of VEGF and GPI, reduced cell proliferation and increased apoptosis. These results suggest that HIF-1 is a potential therapeutic target for pancreatic cancer.