Effect Of Clostridium Difficile Toxin A On The Apoptosis Of K562 Cells And Its Mechanism

Objective To observe the growth inhibition and apoptosis effect of Clostridium difficile toxinA on the leukemia cell lines K562.Methods The proliferative activity of K562 cells exposed to TcdA was tested by MTT assay, cell apoptosis was detected by fluorescent staining and flow cytometry (FCM), the immunocytochemistry and colorimetric assay were employed to detect the protein expressions of Bcl-2/Bax and the activity of Caspase-3, the expression of Survivin mRNA was detected by real-time PCR.Results The proliferation was inhibited in a time-and dose-dependent manner after 24h and 48h of exposure to TcdA, the cells presented the typical morphological changes of apoptosis, the expression of Bcl-2 protein was down-regulated but the expression of Bax protein was significantly increased compared with control group (p<0.05),the levels of Caspase-3 were significantly higher than those in control group(p<0.05),in addition, the expression of Survivin mRNA was decreased in a concentration-dependent manner(p<0.01).Conclusion TcdA inhibited cell growth of K562 by inducing apoptosis.The up-regulation of Bax protein, activity of Caspase-3 and down-regulation of Survivin mRNA may play important roles in these processes.