Mono(2-ethylhexyl) phthalate induces apoptosis in p53-silenced L02 cells via activation of both mitochondrial and death receptor pathways.
Mono(2-ethylhexyl) phthalate (MEHP) is one of the main metabolites of di(2-ethylhexyl) phthalate. The evidence shows that DEHP may exert its toxic effects primarily via MEHP, which is 10-fold more potent than its parent compound in toxicity in vitro. MEHP-induced apoptosis is mediated by either p53-dependent or -independent pathway. However, the detailed mechanism of its toxicity remains unclear. In this study, immortalized normal human liver cell line L02 was chosen, as an in vitro model of nonmalignant liver, to elucidate the role of p53 in MEHP-induced apoptosis. The cells were treated with MEHP (6.25, 12.50, 25.00, 50.00, and 100.00 μM) for 24 and 36 h, then small interfering RNA (siRNA) was used to specifically silence p53 gene of L02 cells. The results indicated that MEHP caused oxidative DNA damage and apoptosis in L02 cells were associated with the p53 signaling pathway. Further study found that MEHP (50.00 and 100.00 μM) induced apoptosis in p53-silenced L02 cells, along with the up-regulations of Fas and FasL proteins as well as increased the Bax/Bcl-2 ratio and Caspase 3, 8, and 9 activities. Additionally, both FasL inhibitor (AF-016) and Caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp- fluoromethylketone (Z-VAD-FMK) could prevent the cell apoptosis induced by MEHP. The findings suggested that MEHP-induced apoptosis in L02 cells involving a Caspases-mediated mitochondrial signaling pathway and/or death receptor pathway. p53 was not absolutely necessary for MEHP-induced L02 cell apoptosis.
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Guangtao
G
Yang
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Wenjuan
W
Zhang
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Qizhi
Q
Qin
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Jing
J
Wang
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Hongyan
H
Zheng
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Wei
W
Xiong
Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.|Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China.
Jing
J
Yuan
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000737:chemistry / Q000378:metabolism; D053181:Caspase 8 / Q000737:chemistry / Q000378:metabolism; D053453:Caspase 9 / Q000737:chemistry / Q000378:metabolism; D061945:Caspase Inhibitors / Q000494:pharmacology; D002460:Cell Line; D004249:DNA Damage / Q000187:drug effects; D004051:Diethylhexyl Phthalate / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D053222:Fas Ligand Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering; D053218:Receptors, Death Domain; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
D061945:Caspase Inhibitors; C491901:FAS protein, human; D053222:Fas Ligand Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D053218:Receptors, Death Domain; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; D004051:Diethylhexyl Phthalate; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9
Fas/FasL; apoptosis; mitochondria; mono (2-ethylhexyl) phthalate; p53