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Glutathione-associated enzymes in the human cell lines of the National Cancer Institute Drug Screening Program.
Mol Pharmacol. 1996 Jul; 50(1):149-59.MP

Abstract

The steady state expression of glutathione S-transferases (GSTs) at both the protein and mRNA level is reported for the 60 tumor cell lines that are used for the National Cancer Institute Drug Screening Program. Individual GST isozymes were separated, identified, and quantified (with reverse-phase calibration curves) through a novel high performance liquid chromatographic procedure. GSTP1 was the predominant isozyme and was found at quantifiable levels in all but two of the cell lines. This isozyme ranged from 0.03% to 2.7% of the total cytosolic protein. For the mu family, 90% of the lines had GSTM2, 68% had GSTM3, but only 28% were positive for the M1 phenotype. The M1 proportion is lower than would be expected from the standard M1 null phenotype for human populations. Isozymes of the alpha family were detected only at very low levels in 35% of the lines. Significant quantitative correlations among enzyme activity, total enzyme protein, and mRNA were shown for GSTP1. However, such relationships were not apparent for the mu or alpha families. Levels of glutathione (GSH), and the transcript levels of other enzymes involved in GSH homeostasis were determined. gamma-Glutamyl cysteine synthetase (gamma-GCS) was present in all cell lines, but did not correlate with levels of intracellular GSH. Glyoxalase-I and gamma-glutamyl transpeptidase, both involved in GSH salvage, were found in 100% and 70% of the cell lines, respectively. Using a pattern-matching computer program, COMPARE, we compared and correlated the arrays of mRNA and protein levels with the pattern of chemosensitivity or chemoresistance of the 60 cell lines with 175 agents constituting a standard agent database. This database is composed of compounds to which a putative mechanism of action has been assigned. Although Pearson correlation coefficients relating the target and drug patterns were generally modest, when the patterns for the enzyme protein and mRNA levels for GST pi were correlated to drug sensitivity patterns, the list of 30 agents most closely matching (for which P < 0.05) was enriched with alkylating agents. gamma-GCS also showed an enrichment of alkylating agents in the COMPARE correlations, indicating that high levels of gamma-GCS may be an important determinant of resistance. In contrast, none of the other enzymes or GSH had patterns of expression that resulted in an obvious correlation to the sensitivity or resistance of alkylating agents.

Authors+Show Affiliations

Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA. kd.tew@fccc.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

8700107

Citation

Tew, K D., et al. "Glutathione-associated Enzymes in the Human Cell Lines of the National Cancer Institute Drug Screening Program." Molecular Pharmacology, vol. 50, no. 1, 1996, pp. 149-59.
Tew KD, Monks A, Barone L, et al. Glutathione-associated enzymes in the human cell lines of the National Cancer Institute Drug Screening Program. Mol Pharmacol. 1996;50(1):149-59.
Tew, K. D., Monks, A., Barone, L., Rosser, D., Akerman, G., Montali, J. A., Wheatley, J. B., & Schmidt, D. E. (1996). Glutathione-associated enzymes in the human cell lines of the National Cancer Institute Drug Screening Program. Molecular Pharmacology, 50(1), 149-59.
Tew KD, et al. Glutathione-associated Enzymes in the Human Cell Lines of the National Cancer Institute Drug Screening Program. Mol Pharmacol. 1996;50(1):149-59. PubMed PMID: 8700107.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Glutathione-associated enzymes in the human cell lines of the National Cancer Institute Drug Screening Program. AU - Tew,K D, AU - Monks,A, AU - Barone,L, AU - Rosser,D, AU - Akerman,G, AU - Montali,J A, AU - Wheatley,J B, AU - Schmidt,D E,Jr PY - 1996/7/1/pubmed PY - 2001/3/28/medline PY - 1996/7/1/entrez SP - 149 EP - 59 JF - Molecular pharmacology JO - Mol. Pharmacol. VL - 50 IS - 1 N2 - The steady state expression of glutathione S-transferases (GSTs) at both the protein and mRNA level is reported for the 60 tumor cell lines that are used for the National Cancer Institute Drug Screening Program. Individual GST isozymes were separated, identified, and quantified (with reverse-phase calibration curves) through a novel high performance liquid chromatographic procedure. GSTP1 was the predominant isozyme and was found at quantifiable levels in all but two of the cell lines. This isozyme ranged from 0.03% to 2.7% of the total cytosolic protein. For the mu family, 90% of the lines had GSTM2, 68% had GSTM3, but only 28% were positive for the M1 phenotype. The M1 proportion is lower than would be expected from the standard M1 null phenotype for human populations. Isozymes of the alpha family were detected only at very low levels in 35% of the lines. Significant quantitative correlations among enzyme activity, total enzyme protein, and mRNA were shown for GSTP1. However, such relationships were not apparent for the mu or alpha families. Levels of glutathione (GSH), and the transcript levels of other enzymes involved in GSH homeostasis were determined. gamma-Glutamyl cysteine synthetase (gamma-GCS) was present in all cell lines, but did not correlate with levels of intracellular GSH. Glyoxalase-I and gamma-glutamyl transpeptidase, both involved in GSH salvage, were found in 100% and 70% of the cell lines, respectively. Using a pattern-matching computer program, COMPARE, we compared and correlated the arrays of mRNA and protein levels with the pattern of chemosensitivity or chemoresistance of the 60 cell lines with 175 agents constituting a standard agent database. This database is composed of compounds to which a putative mechanism of action has been assigned. Although Pearson correlation coefficients relating the target and drug patterns were generally modest, when the patterns for the enzyme protein and mRNA levels for GST pi were correlated to drug sensitivity patterns, the list of 30 agents most closely matching (for which P < 0.05) was enriched with alkylating agents. gamma-GCS also showed an enrichment of alkylating agents in the COMPARE correlations, indicating that high levels of gamma-GCS may be an important determinant of resistance. In contrast, none of the other enzymes or GSH had patterns of expression that resulted in an obvious correlation to the sensitivity or resistance of alkylating agents. SN - 0026-895X UR - https://www.unboundmedicine.com/medline/citation/8700107/Glutathione_associated_enzymes_in_the_human_cell_lines_of_the_National_Cancer_Institute_Drug_Screening_Program_ L2 - http://molpharm.aspetjournals.org/cgi/pmidlookup?view=long&amp;pmid=8700107 DB - PRIME DP - Unbound Medicine ER -