Overexpression of glutathione S-transferase pi enhances the adduct formation of cisplatin with glutathione in human cancer cells

Citation
S. Goto et al., Overexpression of glutathione S-transferase pi enhances the adduct formation of cisplatin with glutathione in human cancer cells, FREE RAD RE, 31(6), 1999, pp. 549-558
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
FREE RADICAL RESEARCH
ISSN journal
1071-5762 → ACNP
Volume
31
Issue
6
Year of publication
1999
Pages
549 - 558
Database
ISI
SICI code
1071-5762(1999)31:6<549:OOGSPE>2.0.ZU;2-D
Abstract
In this paper, we provide direct evidence that glutathione S-transferase pi (GST pi) detoxifies cisplatin (CDDP). We used human colonic cancer HCT8 ce lls sensitive and resistant to CDDP, the level of cisplatin-glutathione add uct (DDP-GSH) being higher in the resistant cells. There was an overexpress ion of GST pi mRNA in these CDDP-resistant cells. Incubation of the cells w ith CDDP resulted in the formation of DDP-GSH dependent on the CDDP concent ration and the incubation time. The formation of DDP-GSH was abolished when the cells were pre-treated with ethacrynic acid or ketoprofen, inhibitors of GST pi. Purified GST pi also catalyzed the formation of DDP-GSH in vitro , with an apparent K-m of 0.23 mM for CDDP and an apparent V-max of 4.9 nmo l/min/mg protein. The increase in DDP-GSH produced by GST pi was linear wit h incubation time up to 3 h and optimal of pH 7.4. A GST ii transfectant ce ll line was constructed in HCT8 cells using a pcDNA3.1 (-)/Myc-His B with a n expression vector containing cDNA for GST pi. Transfection of GST pi cDNA into HCT8 cells resulted in an increase in the expression of GST pi by 1.4 -fold in parallel with an augmentation of the formation of DDP-GSH. These r esults suggest that GST pi Flays a role in the formation of DDP-GSH and the acquisition of resistance to CDDP in cancer cells.