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Gene expression profiling of epothilone A-resistant cells
Peter Atadja1, Yan Yan-Neale, Harry Towbin
1Functional Genomics, Novartis Corporation, Summit, NJ 07901, USA.
Abstract:
In the current study, we isolated sublines of the human breast adenocarcinoma cell line MDA 435 that exhibited increasing resistance to epothilone A, a microtubule-stabilizing cytotoxic agent. The resistant cells did not express P glycoprotein or multidrug resistance-associated protein (MRP) which are known mediators of multidrug resistance (MDR). Two groups of epothilone A-resistant cells were selected: cells which exhibited low resistance to both epothilone A and Taxol, and cells which exhibit low resistance to Taxol but high resistance to epothilone A. cDNA microarrays of epothilone A-resistant and Taxol-resistant cells were utilized to further characterize epothilone A resistance. Hierarchical clustering of genes according to their levels of expression indicated that the majority of genes which were highly expressed in epothilone A-resistant cells but not in taxol-resistant MDR cells encode known interferon-inducible proteins. Genes whose expression increased with increasing epothilone A resistance include microtubule-associated GTPases, cytoskeletal proteins, cell signalling proteins and a drug metabolising enzyme. The majority of the genes that were repressed in both epothilone A- and Taxol-resistant cells encode proteins regulating cellular growth signalling mechanisms.
Insights
Researchers developed epothilone A-resistant breast cancer cells, finding unique gene expression patterns distinct from multidrug resistance (MDR). These patterns involve interferon-inducible proteins and altered cell signaling, offering new insights into drug resistance mechanisms.
Area of Science:
- * Molecular biology
- * Cancer research
- * Pharmacology
Background:
- * Microtubule-stabilizing agents like epothilone A are crucial in cancer therapy.
- * Acquired resistance to chemotherapy, including epothilone A, is a significant clinical challenge.
- * Understanding the molecular mechanisms of drug resistance is vital for developing effective treatments.
Purpose of the Study:
- * To investigate the molecular basis of epothilone A resistance in human breast adenocarcinoma cells (MDA 435).
- * To characterize gene expression profiles associated with epothilone A resistance, differentiating it from known multidrug resistance (MDR) mechanisms.
- * To identify novel genes and pathways involved in epothilone A resistance.
Main Methods:
- * Generation of epothilone A-resistant sublines from the MDA 435 cell line.
- * Phenotypic characterization of resistant cells for cross-resistance to Taxol.
- * Utilization of cDNA microarrays to analyze gene expression profiles in resistant cells.
- * Hierarchical clustering to identify differentially expressed genes.
Main Results:
- * Epothilone A-resistant cells did not express P glycoprotein or multidrug resistance-associated protein (MRP).
- * Gene expression analysis revealed distinct profiles for epothilone A resistance compared to Taxol-resistant MDR cells.
- * Upregulated genes in epothilone A-resistant cells included interferon-inducible proteins, microtubule-associated GTPases, cytoskeletal proteins, and a drug-metabolizing enzyme.
- * Downregulated genes in both epothilone A- and Taxol-resistant cells were associated with cellular growth signaling.
Conclusions:
- * Epothilone A resistance in MDA 435 cells is mediated by mechanisms distinct from classical P glycoprotein or MRP-dependent MDR.
- * Interferon-inducible proteins and altered expression of cytoskeletal and signaling proteins are implicated in epothilone A resistance.
- * The findings provide novel molecular targets and insights into overcoming epothilone A resistance in breast cancer.