The Role of p53 in Marijuana Smoke Condensates-induced Genotoxicity and Apoptosis

OBJECTIVES: Marijuana is one of the most frequently abused drug in Korea and its adverse health effects are controversial. p53 is known to be crucial in regulating the DNA damage responses, and adverse effects can occur when it is regulated by marijuana smoke. We evaluated a role of p53 on genotoxic effect and apoptosis in lung cancer cells exposed to marijuana smoke condensates (MSCs). METHODS: The p53-related genotoxicity and apoptosis of MSCs were evaluated using in vitro bioassay, viz., comet assay, cytokinesis-block micronucleus assay and apoptosis assay. We used two cell lines with differential p53 expression (p53-wildtype (WT) H460 and p53-null H1299). RESULTS: MSCs significantly increased DNA breakages and chromosomal changes in p53-WT H460 and p53-null H1299 cells. The genotoxicity induced by MSCs in p53-null H1299 cells showed greater sensitivity than p53-WT H460 cells. Moreover, MSCs showed a significant increase in reactive oxygen species production and apoptosis. The apoptotic responses induced by MSCs were higher in p53-WT H460 cells than in p53-null H1299 cells. Significantly increased mRNA expression or apoptosis related genes, including p53, caspase-3, and Bax/Bcl-2 ratio were observed in the p53-WT H460 cells exposed to MSCs. CONCLUSIONS: These results suggest that MSCs induce DNA/chromosomal damages and apoptosis in human lung cancer cells and p53 plays an important role in the cellular response to MSCs. The present study may have border implications for our understanding of pulmonary diseases.

Effect of Aging on the Pluripotential Capacity of Human Bone Marrow Derived Mesenchymal Stem Cells / 대한정형외과학회잡지

PURPOSE: The aim of study was to compare the differentiation capacity of mesenchymal stem cells (MSCs) obtained from human bone marrow (BM) according to the age of the donors. MATERIALS AND METHODS: MSCs were isolated from the BM of young (n=16, 12.5+/-5.8 years) and elder (n=4, 48.5+/-7.2 years) patients with the consent of them. We analyzed the cell morphology and the cell surface markers of the MSCs. In addition, we assessed the cell senescence with serial cultures from both age groups. Cell pluripotentiality was analyzed by osteogenic, chondrogenic, and adipogenic induction media. We performed RT-PCR, a measurement of expression of alkaline phosphatase, and staining with von Kossa, safranin O, and oil red O stain. RESULTS: All of the MSC samples tested, irrespective of the age of the donors, MSCs were all successfully isolated from twenty bone marrows. However, the number of cells of from the young donors was five times greater than that of the elderly donors. Senescence was observed over 10 passages in both age groups. The immunophenotypes of both age groups showed similar patterns. MSCs obtained from young and older donors showed the potential to differentiate into osteogenic, chondrogenic, and adipogenic lineages with no difference for both age groups. CONCLUSION: Our study supports that age does not influence the pluripotential capacity of human BM derived MSCs.