Effects Of Tcd A On Proliferation, Apoptosis And Multidrug Resistance Of K562/A02 Cells

Objective:To evaluate the effects of Clostridium difficile toxin A on proliferation, apoptosis and multidrug resistance (MDR) of K562/A02 cells.Methods:The growth inhibition effect of Ted A on K562/A02 cells and the MDR of cells was assayed by MTT method, apoptosis was detected by flow cytometry (FCM), the expression of P-gp protein was examined by Western blot, and caspase-3 activity was measured using the caspase-3 activity kit.Results:Ted A inhibits the growth of K562/A02 cells in concentration-and time-dependent manner, the inhibition rate of K562/A02 cells treated with Ted A (50ng/ml,100 ng/ml,200 ng/ml,400 ng/ml and800 ng/ml)for 24 hours was reached (8.76±0.76)%,(28.55±0.43)%,(47.89±0.27)%,(58.08±0.06)% and (57.70±0.79)% respectively, After the treatment with Ted A, K562/A02 cells in GO/G1 phase were increased, but S phase cells were decreased, the apoptosis rates of 200ng/ml and 400ng/ml concentration group were 14.05% and 22.89%.The resistant folds of K562/A02 cells to adriamycin (ADM), daunorubicin (DNR) and cytarabine (Ara-C) were 87.06, 21.91 and 7.46, in combination with the chemotherapy drugs, Ted A (50ng/ml) could significantly inhibit the proliferation of K562/A02 cells, and reduce the IC50 of these drugs, and the reversal folds were 3.09,2.89 and 2.79 respectively. The expression of P-gp protein was down-regulated and caspase-3 was activated in a concentration-dependent manner.Conclusion:TcdA could inhibit growth and induce apoptosis in K562/A02 cells, and partly reversed MDR, the mechanism may be related with the down-regulation of P-gp and activation of caspase-3.