RESUMO
OBJECTIVE: To study the effect of ursolic acid (UA), apentacyclic triterpene acid, on MCF-7 cell apoptosis, and probable mechanism involved by detecting the expressions of caspase-3 and poly ADP-ribose polymerase(PARP) at protein level. METHOD: MCF-7 cells were cultured with different concentrations of UA. Growth inhibition of UA on MCF-7 cells was evaluated by MTT assay. Cell cycle and sub-G1 peak were performed by FCM. Morphologic changes of UA-treated cells were observed by light microscope. Apoptotic cells with condensed or fragmented nuclei were visualized by Ho 33258 staining by a fluorescence microscope (EX: U. V.). The protein expression of caspase-3 and PARP was analyzed by immunofluorescence cell staining (SABC-Cy3). RESULT: 24 hours after UA treatment, inhibition of MCF-7 cell growth was concentration-dependent. The IC50 value for UA was (22.6 +/- 3.0) micromo x L(-1). Cell cycle anaysis by FCM showed that 50 micromol x L(-1) of UA arrested MCF-7 cell cycle at G0 - G1 phase. Morphological changes of MCF-7 Cells exhibited many of the hallmark features of apoptosis, including chromatin clumps and aggregation and DNA fragmentation. UA increased caspase-3 protein expression. CONCLUSION: The results suggest that UA evokes MCF-7 cell apoptosis is correlation with the up-regulation of caspase-3. Our study indicated that UA might be a potential Chinese medical component for breast neoplasm.