RESUMO
<p><b>OBJECTIVE</b>To investigate the apoptosis of bladder cancer cell 5637 induced by pseudolaric acid B in vitro and its mechanism.</p><p><b>METHOD</b>The cell proliferation was detected by MTT assay;the cell cycle was measured by flow cytometry; the cell apoptosis was observed by flow cytometry with Annexin V-FITC/PI double staining; the expressions of survivin protein and caspase-3 protein were detected by Western blot assay.</p><p><b>RESULT</b>It showed that pseudolaric acid B remarkably induced apoptosis of 5637 cell line. Moreover, pseudolaric acid B suppressed survivin and up-regulated caspase-3 expression.</p><p><b>CONCLUSION</b>Pseudolaric acid B inhibits the proliferation and induces the apoptosis of 5637 cells. The molecular mechanism of pseudolaric acid B inducing the apoptosis of 5637 cells may be associated with its action of down-regulating the expression of survivin, and up-regulating the expression of caspase-3.</p>