A comparison of DNA damage induced by aflatoxin B1 in hepatocyte-like cells, their progenitor mesenchymal stem cells and CD34(+) cells isolated from umbilical cord blood.
This study compared the sensitivity of differentiated hepatocyte-like cells, their progenitor mesenchymal stem cells (MSCs) and CD34(+) stem cells to DNA damage and toxicity induced by aflatoxin B1 (AFB1). The hepatocyte-like cells and their progenitor cells (isolated from umbilical cord blood (UCB)) were each treated with AFB1 on day 15 of differentiation. Cell toxicity and genotoxicity effects were assessed using MTT and alkaline comet assays. AFB1 treatment resulted in a dose- and time-dependent inhibition of cell growth. The IC(50) values of AFB1 for hepatocytes differentiated from CD34(+) and MSCs were within the same range (44.7-46.8μM). The IC(50) calculated for non-differentiated MSCs and CD34(+) cells was slightly lower (42.0-43.4μM) than that calculated for their differentiated counterparts. However, the extent of DNA damage was different in differentiated and non-differentiated cells. The percentages of DNA (% DNA) in comet tails measured in hepatocytes differentiated from MSCs exposed to AFB1 (0, 2.5, 10 and 20μM) for 24h were ∼15, 55, 65 and 70%, respectively. In comparison, hepatocytes from CD34(+) cells were more resistant to AFB1-induced DNA damage. Hepatocyte-MSCs were most sensitive to DNA damage, followed by UCB-CD34(+) cells, then UCB-MSCs and finally hepatocyte-CD34(+) cells. These results clearly showed that stem cells from different sources have different sensitivities to DNA damaging agents. These differences can be assigned to the expression levels of cytochrome P450 (CYP) particularly CYP3A4 in non-differentiated and differentiated cells. These data are useful in better understanding the susceptibility/resistance of stem cells in the process of differentiation to environmental toxicants.
Ghaderi
Masoumeh
M
Department of Biochemistry, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
Allameh
Abdolamir
A
Soleimani
Masoud
M
Rastegar
Hossein
H
Ahmadi-Ashtiani
Hamid Reza
HR
D016604:Aflatoxin B1 / Q000494:pharmacology*; D018952:Antigens, CD34 / Q000097:blood; D002470:Cell Survival; D002478:Cells, Cultured; D020552:Comet Assay; D051544:Cytochrome P-450 CYP3A / Q000235:genetics; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005312:Fetal Blood / Q000166:cytology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011042:Poisons / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D018952:Antigens, CD34; D011042:Poisons; D016604:Aflatoxin B1; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human