MTT assays cannot be utilized to study the effects of STI571/Gleevec on the viability of solid tumor cell lines
- 355 Downloads
This study will determine whether MTT assays accurately assess the effect of STI571 (Gleevec; Abl kinase inhibitor) on the viability of cancer cells containing highly active Abl kinases.
Growth kinetics, tritiated thymidine, fluorescent caspase, MTT, and Cell Titer Glo (CTG) assays were used to determine the effect of STI571 on growth, proliferation, apoptosis, and viability of melanoma and breast cancer cells.
STI571 inhibited growth and proliferation, and increased apoptosis. However, MTT assays indicated that STI571 increased cell viability. In contrast, STI571 induced a dose-dependent decrease in viability using CTG assays.
Doses of STI571 (1–10 μM) required to inhibit endogenous Abl kinases interfere with the MTT assay, and therefore MTT cannot be used to determine the effect of STI571 on viability using these doses. Additionally, caution should be utilized when interpreting the results of MTT assays used to screen kinase inhibitors for anti-cancer activity, as drug effectiveness may be minimized.
KeywordsSTI571 Gleevec Abl MTT Cell Titer Glo (CTG) Viability
This work was supported by National Institute of Health Grant P20 RR20171 from the National Center for Research Resources, and National Institute of Health/National Cancer Institute Grant 1R01CA116784 to R.P. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NIH. We thank Elisabeth Buchdunger (Novartis Pharmaceuticals, Basel, Switzerland) for providing STI571, and Leann Fiore for critically reading the manuscript.
- 2.Pendergast AM (2001) BCR-ABL protein domain, function, and signaling. In: Helmann R (ed) Chronic myeloid leukaemia: biology and treatment. Martin Dunitz Lt, London, pp 19–39Google Scholar
- 10.Berridge MV, Tan AS (1993) Characterization of the cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT): subcellular localization, substrate dependence, and involvement of mitochondrial electron transport in MTT reduction. Arch Biochem Biophys 303:474–482PubMedCrossRefGoogle Scholar
- 13.Pagliacci MC, Spinozzi F, Migliorati G, Fumi G, Smacchia M, Grignani F, Riccardi C, Nicoletti I (1993) Genistein inhibits tumour cell growth in vitro but enhances mitochondrial reduction of tetrazolium salts: a further pitfall in the use of the MTT assay for evaluating cell growth and survival. Eur J Cancer 29A:1573–1577PubMedCrossRefGoogle Scholar
- 17.Mayorga ME, Sanchis D, Perez de Santos AM, Velasco A, Dolcet X, Casanova JM, Baradad M, Egido R, Pallares J, Espurz N, Benitez D, Mila J, Malvehy J, Castel T, Comella JX, Matias-Guiu X, Vilella R, Marti RM (2006) Antiproliferative effect of STI571 on cultured human cutaneous melanoma-derived cell lines. Melanoma Res 16:127–135PubMedCrossRefGoogle Scholar