title: Alleviation of benzo[a]pyrene-diolepoxide-DNA damage in human lung carcinoma by glutathione S-transferase M2.
abstract: Cellular detoxification is important for the routine removal of environmental and dietary carcinogens. Glutathione S-transferases (GST) are major cellular phase II detoxification enzymes. MRC-5 cells have been found to exhibit significantly higher GST activity than human H1355 cells. This study investigates whether GST-M2 activity acts as a critical determinant of the target dose of carcinogenic benzo[a]pyrene-diolepoxide (BPDE) and whether it has an effect on MDM2 splicing in the two cell lines. We used RT-PCR to clone Mu-class GST cDNA. Two forms of GST coming from the cell lines were characterized as GST-M2 (from MRC-5 cells) and GST-M4 (from H1355 cells). Nested-PCR showed that BPDE-induced MDM2 splicing had occurred in the H1355 cell line but not in normal MRC-5 cells. Furthermore, using nested-PCR and competitive ELISA, we found that in H1355 cells modified to stably overexpress GST-M2, splicing was abolished and BPDE adducts appeared in low abundance. In conclusion, exogenously overexpressed GST-M2 was effective in reducing BPDE-induced DNA damage in H1355 cells. The catalytic activity of GST-M2 may play an important future role in lowering the incidence of BPDE-induced DNA damage.
authors.affiliation: Institute of Medical and Molecular Toxicology, Chung Shan Medical University, 110, Sec. 1, Chien-Kuo N. Road, Taichung, Taiwan 40203, ROC.
authors.forename: Mao-Wen
authors.initials: MW
authors.lastname: Weng
authors.forename: Yi-Min
authors.initials: YM
authors.lastname: Hsiao
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Chiou
authors.forename: Shun-Fa
authors.initials: SF
authors.lastname: Yang
authors.forename: Yih-Shou
authors.initials: YS
authors.lastname: Hsieh
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Cheng
authors.forename: Chieh-Hsiang
authors.initials: CH
authors.lastname: Yang
authors.forename: Jiunn-Liang
authors.initials: JL
authors.lastname: Ko
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000633:toxicity*; D001483:Base Sequence; D045744:Cell Line, Tumor; D018736:DNA Adducts; D004249:DNA Damage / Q000187:drug effects*; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008175:Lung Neoplasms; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D018736:DNA Adducts; D017931:DNA Primers; D007527:Isoenzymes; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D005982:Glutathione Transferase; C412602:glutathione S-transferase Mu 2