[Experimental study of simvastatin induced apoptosis of K562 cells by caspase-12 activation].

OBJECTIVE: To explore the apoptotic effect of simvastatin on K562 cells through Caspase-12 activation. METHODS: Morphological changes of apoptotic cells were observed by Hoechst33258 fluorescent staining under fluorescent microscope; Apoptosis rate of cells was determined with annexin V-FITC/PI double staining by flow cytometry; Intracellular calcium concentration ([ca2+]i) was measured by Laser Scanning Confocal Microscope(LSCM); The expression levels of GRP78 and Calpain gene mRNA were determined by RT-PCR; The expression levels of Caspase-3,-6,-7,-9,-12 and GRP78 proteins were evaluated by Western blot. RESULTS: Typical morphological changes of K562 apoptosis cells were observed post 72 hours treated with 10, 20, 30 micromol/L simvastatin. The apoptotic rates of K562 cells were (12.41 +/- 0.32)%, (19.08 +/- 0.26)% and (23.41 +/- 0.36)%, respectively. The fluorescent intensities were 43 +/- 2.9, 54 +/- 2.7 and 64 +/- 2.6, respectively in K562 cells treated with 10, 20, 30 micromol/L simvastatin, which represented the increase of [ca2+]i The expression levels of GRP78 and Calpain gene mRNA were up-regulated. And the cleavage and activation of Caspase-3,-6,-7,-9,-12 and upregulation of GRP78 expression were demonstrated by Western blot detection for the treated cells. CONCLUSION: Caspase-12 is a important pathway of apoptosis in cells and participates simvastatin-induced apoptosis in K562 cells.