Effects of Clostridium Difficile Toxin A on Proliferation of K562 Cells

This study was aimed to investigate the effect of clostridium difficile toxin A(Tcd A) on proliferation of K562 cells and its mechanism.The proliferative activity of K562 cells exposed to Tcd A was tested by MTT assay;cell cycle distribution and mitochondrial membrane potential were analyzed by flow cytometry;the protein expression of cytochrome C and DNA fragmentation were observed by immunohistochemistry staining and agarose gel electrophoresis respectively.The results indicated that Tcd A inhibited proliferation of K562 cells in a time-and concentration-dependent manner.Cells were arrested at G0/G1 phase.Peak of apoptosis appeared.The protein expression of cytochrome C increased as compared with control group(p0.05).Agarose gel electrophoresis of DNA from K562 treated with Tcd A revealed a "ladder" pattern.It is concluded that clostridium difficile toxin A can inhibit proliferation and induce apoptosis of K562 cells.The mechanism may be in relation to decrease of mitochondrial membrane potential and the release of cytochrome C from mitochondria matrix.