OBJECTIVETo determine whether human prostate cancer cell lines undergo epithelial-mesenchymal transition (EMT) and become more invasive when induced by HIF-1alpha, and to explore the underlying molecular mechanism.

METHODSThe cell line LNCaP, appropriate for the HIF-1alpha induction test, was screened out from 4 different EMT-negative prostate cell lines through vimentin gene detection by RT-PCR. The recombinant plasmid pCDNA3. 1(-)/HIF-1alpha was constructed and transfected into LNCaP with the Lipofectamine 2000 system. The control plasmid pCDNA3.1 (-) was transfected by the same method. The positive clone cells were selected by G418 and confirmed by Western blot and immunofluorescence staining. Then a Transwell polycarbonate filter, coated with 100 micol Matrigel at 1:20 dilution in the serum-free medium, was used to analyze the invasive potency. The expression of E-cadherin and vimentin was detected by Western blot.

RESULTSAmong the 4 different EMT-negative cell lines, LNCaP was the only one that expressed the vimentin gene but not protein. The expression of HIF1alpha was obviously higher in LNCaP/HIF1alpha than in LNCaP/pCDNA3. 1 (- an LNCaP. The number of the LNCaP/HIF1alpha cells that penetrated through the Transwell polycarbonate filter was significantly larger than that of the LNCaP and LNCaP/pCDNA3. 1(-) cells. Compared with the LNCaP/pCDNA3.1(-) and LNCaP cells, the expression of vimentin was up-regulated, while that of E-cadherin down-regulated, in LNCaP/HIF1alpha.

CONCLUSIONThe over-expression of HIF-1alpha could induce EMT in the human prostate carcinoma cell line LNCaP and enhance its invasiveness through E-cadherin and vimentin regulation.