title: Characterization of a human melanoma cell line with non-oestrogen receptor dependent tamoxifen resistance.
abstract: While investigating the mechanism of synergistic cytotoxicity between tamoxifen (TAM) and cisplatin (DDP) we developed a TAM-resistant variant of the human melanoma cell line T-289. We sought to characterize this cell line with respect to the effect of TAM resistance on a variety of different intracellular cell cycle control and apoptotic pathways. A TAM-resistant variant cell line (289 TAMs) was developed and the technique of Western analysis was to determine the changes in protein expression that occurred as a result of the development of TAM resistance. In this model, TAM resistance resulted in an increase in the detectable basal levels of cyclin E, GADD 153, p16, BAX, Bcl-XL, and wild-type and mutant p53, an increase in TAM induction of p16, and a decrease in the detectable basal levels of cyclin D1, p21 and p27. There were no detectable changes in the levels of pRb. In the TAM-resistant variant, p21 levels were essentially undetectable, while p27 was present and maintained its response to TAM Induction, albeit at a much lower level. This investigation demonstrates that the development of TAM resistance is associated with a change in the detectable levels of a variety of cell cycle control and apoptosis-related proteins. While the exact role that each change plays in the development of tamoxifen resistance remains to be determined, these data suggest that the development of resistance to a particular agent results in changes in multiple, seemingly unrelated pathways. These data have implications for future studies in both the laboratory and the clinic.
authors.affiliation: Department of Medicine, Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, USA. emcclay@ucsd.edu
authors.forename: E F
authors.initials: EF
authors.lastname: McClay
authors.forename: J A
authors.initials: JA
authors.lastname: Jones
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D017209:Apoptosis; D018797:Cell Cycle Proteins; D019938:Cyclin D1 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D051358:Cyclin-Dependent Kinase 4; D050762:Cyclin-Dependent Kinase Inhibitor p15; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D013629:Tamoxifen / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: D018931:Antineoplastic Agents, Hormonal; C494826:BAX protein, human; C494811:BCL2L1 protein, human; C493956:CDKN1A protein, human; C493966:CDKN2B protein, human; D018797:Cell Cycle Proteins; D019927:Cyclin E; D050762:Cyclin-Dependent Kinase Inhibitor p15; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011960:Receptors, Estrogen; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D013629:Tamoxifen; D019938:Cyclin D1; D050760:Cyclin-Dependent Kinase Inhibitor p27; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases