Effect Of Curcumin On K562 Cells And Expression Of HDAC₈ With Single And Combined With STI571

Objective:To investigate the influence of curcumin on the proliferation and apoptosis of K562 cells with single and combined with STI571, and it's effect on the expression of HDAC8.Methods: Cell proliferation was studied by tetrazolium dye assay, the apoptosis of K562 cells was detected by flow cytometry through Annexin-V FITC/PI double stain. The effect of the combining use of the two drugs was estimated by the q value, q=E(A+B)/[EA+EB(1-EA)]. E(A+B) was the inhibition rate of the combining use of the two drugs, EA and EB were the inhibition rates of the single use of the two drugs. When q >1.15, it means the two drugs have a cooperated effect; while it means an antagonistic effect when q<0.85. The influence of curcumin on the expression of HDAC8 of K562 Cells was assayed by immunohistochemistry(SABC). Results: Curcumin and STI571 could inhibit the proliferation of K562 cells by a time- and dose- dependent manner, their IC50 at 36h were 22.23±2.15μmol/L and 0.21±0.03μmol/L, while combined each other, the inhibition rates were much higher. When combined 0.2μmol/L STI571 with 15μmol/L and 30μmol/L curcumin, the inhibition rates at 36h were 72.59±2.81% and 88.93±1.58%, the q values were 1.17 and 1.18 each other. Combined with curcumin and STI571 could increased the apoptosis rates obviously. After 18 hours, the apoptosis rates of combined with 0.2μmol/L STI571 and 10μmol/L,30μmol/L curcumin were 15.44±2.92%,28.16±3.22%,the q value were 1.08 and 1.50. Curcumin could inhibit the expression of HDAC8 of K562 cells, the ? value of 10μmol/L curcumin at 8h and 12h were 2.72±0.13 and 1.78±0.21, compared with the positive control, P<0.05.Conclusion: Combining with curcumin and STI571 could increased the effect of inhibiting the proliferation and inducing the apoptosisof K562 cells. The competence of HDAC8 of K562 cells might inhibited by curcumin.