[Molecular mechanism of Aurora kinase inhibitor PHA739358 in inhibited proliferation and induced apoptosis of breast cancer cells].

OBJECTIVE: To explore the molecular mechanisms of Aurora kinase inhibitor PHA739358 in inhibited proliferation and in vitro induced apoptosis of breast cancer cells. METHODS: The in vitro cultured T47D cells in logarithmic growth phase were used. The effects of PHA739358 on cell proliferation were examined by MTT (methyl thiazolyl tetrazolium) assay. The variety of nuclear and spindle morphologies was examined by immunofluorescence. And G2/M arrest was determined by flow cytometry. The morphological changes of apoptotic cells were observed by fluorescent microscope. The levels of Aurora kinase relative protein expression phosphonate-AuroraA (p-AuroraA), AuroraA, phosphonate-histone H3 (p-histone H3), histone H3, cell cycle-specific protein expression CyclinB1, cell cycle regulative protein expression Cdc2, Cdc25c, phosphonate-Cdc2 (p-Cdc2), phosphonate-Cdc25c (p-Cdc25c) and apoptosis relative protein expression PARP, Bcl-2 and Bax were detected by Western blot. The apoptotic rate was examined by flow cytometer. RESULTS: PHA739358 obviously inhibited the proliferation of T47D cells after a 24 h or 48 h treatment in a dose-dependent and time-dependent manner. Their IC50 values were (3.44 ± 0.54) and (0.21 ± 0.67) µmol/L respectively. Flow cytometry showed that G2/M arrested in a dose-dependent manner. PHA739358 dose-dependently and time-dependently promoted the dissection of PARP (poly (ADP-ribose) polymerase); down-regulated the expressions of Bcl-2, p-AuroraA, p-histone H3, CyclinB1 and up-regulated the levels of Bax, p-Cdc25c, p-Cdc2, P21 and P53 protein. PHA739358 had no significant effects on the expressions of AuroraA and histone H3. Flow cytometry and fluorescence microscope showed that PHA739358 significantly induced apoptosis. Flow cytometry showed the rate of apoptosis significantly increased from 0.31% ± 0.03% to 40.6% ± 0.81%. CONCLUSION: The proliferation-inhibiting and apoptosis-inducing effects of PHA739358 may provide new therapeutic approaches of breast cancer.