Identification of Differentially Expressed mRNA Transcripts in Drug-resistant Versus Parental Human Melanoma Cell Lines

Background: Malignant melanoma resistance to chemotherapy remains a major limitation to treatment. Our aim was to identify genes associated with drug resistance, in order to better understand the molecular events underlying the drug-resistant phenotype. Materials and Methods: A human melanoma cell line and its drug-resistant variants obtained by selection with MNNG or 6-thioguanine were used. Alterations in gene expression were characterized by differential display reverse transcription-polymerase chain reaction (DDRT-PCR). Prominent mRNA fragments present in selected variants and not in the parental cells were identified and characterized by cloning and sequencing. Differential expression was confirmed by real-time RT-PCR. Results: Three functionally distinct transcriptional products were demonstrated: the chaperonin subunit TCP 1-zeta-6A (CCT6A), the hyaluronan receptor CD44 and LPPR-2, the lipid phosphate phosphatase-related protein type-2. Conclusion: Genes with altered expression were identified in drug-resistant variants. The identified molecules may provide new insights into the molecular basis for melanoma resistance to chemotherapy.