RESUMEN
<p><b>OBJECTIVE</b>To study the effect of laminarin sulphate (LAMS) on the expressions of PTEN and P27kip1 in androgen-independent prostate cancer PC-3 cells in vitro, and investigate the mechanism of its anti-tumor action.</p><p><b>METHODS</b>The inhibitory effects of different concentrations of LAMS (0, 50, 100, 200 microg/ml) on androgen-independent prostate cancer PC-3 cells were detected by WST-8 assay. The morphology of PC-3 cells was observed under the fluorescence microscope, and the cell cycle and apoptosis were analyzed by flow cytometry. The mRNA and protein levels of PTEN and P27kip1 were measured by RT-PCR and Western blot.</p><p><b>RESULTS</b>LAMS inhibited the proliferation of androgen-independent prostate cancer PC-3 cells in a dose- and time-dependent manner, and the cell cycle analysis showed that PC-3 cells were arrested in the S phase after treated with different concentrations of LAMS. The rate of apoptosis was increased and many typical apoptotic morphological features were observed under the fluorescence microscope. The PTEN and P27kip1 expressions at mRNA and protein levels were increased in a dose-dependent manner.</p><p><b>CONCLUSION</b>LAMS can inhibit the proliferation, arrest the cell cycle in the S phase and induce apoptosis of prostate cancer PC-3 cells. The significantly increased expressions of PTEN and P27kip1 may be one of the mechanisms for LAMS inhibiting prostate cancer PC-3 cells.</p>