title: Cellular response to a glutathione S-transferase P1-1 activated prodrug.
abstract: TER286 [gamma-glutamyl-alpha-amino-beta(2-ethyl-N,N,N', N'-tetrakis(2-chloroethyl)phosphorodiamidate)-sulfonyl-propionyl-( R)- (-) phenylglycine] is a novel nitrogen mustard prodrug that is preferentially activated by glutathione S-transferase P1-1 (GSTP1-1). A human promyelocytic leukemia /TER286-resistant cell line was selected by chronic, long-term exposure to the prodrug. Although resistance was not readily achieved, eventually a 5-fold resistant clone was isolated. Cross-resistance to melphalan occurred, but not to doxorubicin (Adriamycin), taxol, and gamma-glutamyl-S-(benzyl)cysteinyl-R(-)-phenyl glycine diethyl ester, a GSTP1-1 inhibitor. The protein and transcript levels and enzymatic activity of GSTP1-1 were reduced significantly in the selected resistant line. GSTalpha levels were unchanged, and GSTmu was undetectable. Although glutathione levels were elevated in human promyelocytic leukemia/TER286 cells, no changes in the expression of thiol-related genes including gamma-glutamylcysteine synthetase, gamma-glutamyl transpeptidase, or multidrug resistance protein were found. A 7-fold increase in catalase expression in the resistant cell line indicated an adaptive response to oxidative and electrophilic stress, and this was also reflected in the lower prevalence of drug-induced DNA single-strand breaks in the resistant cells. Mouse embryo fibroblast GSTP1-1(-/-) cells exhibited 2-fold resistance to TER286 compared with GSTP1-1(+/+) cells. NIH3T3 cells transfected with combinations of gamma-GCS and multidrug resistance protein exhibited enhanced resistance to TER286, although the degree of resistance was impaired by cotransfection of GSTP1-1. These results are consistent with responses in the TER286-resistant cells indicative of GSTP1-1-mediated mechanism of activation. In consequence, these data support the rationale that tumors expressing high levels of GSTP1-1 will be more sensitive to the cytotoxic effects of the drug.
authors.affiliation: Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Rosario
authors.forename: M L
authors.initials: ML
authors.lastname: O'Brien
authors.forename: C J
authors.initials: CJ
authors.lastname: Henderson
authors.forename: C R
authors.initials: CR
authors.lastname: Wolf
authors.forename: K D
authors.initials: KD
authors.lastname: Tew
mesh_terms: D016475:3T3 Cells; D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000378:metabolism* / Q000494:pharmacology; D003603:Cytotoxins / Q000378:metabolism* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000378:metabolism*; D018922:HL-60 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D011355:Prodrugs / Q000378:metabolism* / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003603:Cytotoxins; D007527:Isoenzymes; D011355:Prodrugs; C107479:TER 286; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; C496557:Gstp1 protein, mouse; D005978:Glutathione