Effects of aflatoxin B۱ on DNA damage and P۵۳geneamplification in hepatocyte-like cells differentiated from mesenchymal stem cells and CD۳۴+ cellsobtained fromhuman umbilical cord blood

Background: Differentiation ofmesenchymal stem cells (MSCs) to hepatocyte-like cells could be associated with development of liver function factors. The impact of differentiation-dependent changes on DNA integrity is not well understood. In this study, hepatocytes and their progenitor stem cells were treated with aflatoxin B۱ (AFB۱) and amplification of selected genes linked to DNA damage was examined. Methods: MSCs and CD۳۴+ cells isolated from umbilical cord blood (UCB) were treated with AFB۱ (۰, ۲.۵, ۱۰ and ۲۰ µM) in selective media supporting the hepatocyte differentiation. After ۲۴ htreatment the DNA damage (Comet assay) and amplification rates ofP۵۳ and β-globin genes were measured using real time polymerase chain reaction (QPCR). Results:The results show that AFB۱ treatments resulted in a concentration- dependent increase in the DNA damage and suppression of the specific gene amplification. The extent of DNA damage was significantly greater in hepatocytes differentiated from MSCs when compared to those obtained from CD۳۴+ cells. The effects of AFB۱ on the rate of selected gene amplification in QPCR showed that the lesions (expressed as lesions/۱۰ kb) in P۵۳ and β-globin genes was significantly greater in hepatocytes derived from MSCs as compared to the cells derived from CD۳۴+ cells. Conclusions: These data together with the results of cytochrome P۴۵۰ (CYP۳A۴) expression in the cells suggest that the non-differentiated stem cells are probably less vulnerable to genotoxic agents as compared to hepatocytes differentiated from them.

کلیدواژه ها:

Aflatoxin B۱ ، Hepatocytes ، Stem cells ، Real time PCR ، DNA damage ، CYP۳A۴