BACKGROUNDHypoxia-inducible factor-1alpha (HIF-1alpha) is a transcriptional factor that could improve the stimulation of angiogenesis and the metabolic adaptation of tumor cells to hypoxia. A recent study showed that HIF-1alpha could induce colon cancer cells epithelial-mesenchymal transition (EMT). However, no evidence indicates a similar correlation in human prostate cancer cells. This study was designed to evaluate the effect of HIF-1alpha over-expression on the EMT in human prostate cancer cells.

METHODSWe selected the appropriate cell line for HIF-1alpha induction from those EMT negative prostate cell lines through vimentin gene detection by RT-PCR. As the result, LNCaP cell line is the best one for further experiment. LNCaP cells were transfected with recombinant plasmid pcDNA3.1 (-)/HIF-1alpha and pcDNA3.1 (-) control vector by Lipofectamine 2000 system. The positive cell colonies were confirmed by indirect immunofluorescence labeling. Then Transwell polycarbonate filter was used to analyze the invasive potency. The expression of EMT associated proteins, E-cadherin and vimentin, was detected by Western blotting.

RESULTSAmong four of the EMT negative cell lines, LNCaP was the only one expressed the vimentin gene but not the associated protein. The expression level of HIF-1alpha in LNCaP/HIF-1alpha was distinctly higher than that in LNCaP/pcDNA3.1 and LNCaP. The cell numbers of LNCaP/HIF-1alpha that penetrated through the Transwell filter were higher than that of LNCaP/pcDNA3.1 and LNCaP. Compared with the LNCaP/pcDNA3.1 and LNCaP cells, the expression of vimentin was up-regulated in LNCaP/HIF-1alpha, whereas the expression of E-cadherin was down-regulated.

CONCLUSIONSOver-expression of HIF-1alpha stimulates the invasion potency of human prostate carcinoma cells through EMT pathway. The expression of E-cadherin and vimentin, playing established roles in EMT, could be regulated by HIF-1alpha in human prostate cancer cell line.