Alleviation of benzo[a]pyrene-diolepoxide-DNA damage in human lung carcinoma by glutathione S-transferase M2.
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.
Weng
Mao-Wen
MW
Institute of Medical and Molecular Toxicology, Chung Shan Medical University, 110, Sec. 1, Chien-Kuo N. Road, Taichung, Taiwan 40203, ROC.
Hsiao
Yi-Min
YM
Chiou
Hui-Ling
HL
Yang
Shun-Fa
SF
Hsieh
Yih-Shou
YS
Cheng
Ya-Wen
YW
Yang
Chieh-Hsiang
CH
Ko
Jiunn-Liang
JL
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
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