ABCChips as New Diagnostic Tool to Monitoring Multidrug Resistance in Human Tumor Cells to Chemotherapeutics Agents by Expression Profiling of ATP-Binding Cassette Transporter Genes.

A major problem in the treatment of tumors represents the development of resistance to chemotherapy. Many mechanisms are responsible for the failure of treatment, the main one being the activation of the ABC transporters. In the present investigation, we developed a low density DNA microarray which contains 38 ABC transporter genes. This tool has been validated with three different characterized multidrug-resistant sublines (CEM/ADR5000, HL60/AR, MCF7-CH1000) and their corresponding drug-sensitive parental cell lines (CCRF-CEM, HL60, MCF7). The multidrug-resistant cell lines used are known to overexpress either the MDR1, MRP1, or BCRP genes. Interestingly, we found not only the overexpression of these genes but also of other ABC transporter genes by using low density microarrays. These results were corroborated by quantitative real time RT-PCR. The microarray allowed the determination of the expression profile of ABC transporters in a single hybridization experiment and may, hence harbor the potential as diagnostic tool to detect drug resistance in the clinic.