Differential miRNA expression profiles in hepatocellular carcinoma cells and drug-resistant sublines

Altered expression of miRNAs may contribute to multidrug resistance (MDR) in human cancers. This study investigated the association between miRNAs and MDR in five different drug-resistant hepatocellular carcinoma (HCC) cell sublines. The HCC Huh-7 cell line was treated with adramycin (ADM), cisplatin (DDP), carboplatin (CBP), mitomycin C (MMC) or vincristine (VCR) at increasing concentrations to develop drug-resistant sublines. The cell viability MTT assay was used to detect drug resistance. Five different drug-resistant HCC sublines, Huh-7/ADM, Huh-7/CBP, Huh-7/DDP, Huh-7/MMC and Huh-7/VCR, were established. Cells that were resistant to one drug were also found to be resistant to the other drugs. miRNA microarrays were analyzed to identify differential miRNA expression profiles in these cell lines, and real-time PCR was used to validate miRNA microarray data. miRNA microarray analysis showed that there were 53 upregulated miRNAs in Huh-7/ADM, 56 in Huh-7/CBP, 58 in Huh-7/DDP, 58 in Huh-7/MMC and 49 in Huh-7/VCR, whereas there were 52 downregulated miRNAs in Huh-7/ADM, 50 in Huh-7/CBP, 41 in Huh-7/DDP, 55 in Huh-7/MMC and 56 in Huh-7/VCR. Moreover, 26 simultaneously upregulated and 25 simultaneously downregulated miRNAs were noted in the Huh-7/ADM, Huh-7/CBP, Huh-7/DDP and Huh-7/MMC sublines compared to the parental Huh-7 cell line. In contrast, among these 51 upregulated and downregulated miRNAs, 12 miRNAs were upregulated and 13 miRNAs were downregulated in Huh-7/VCR. Upregulation of miR-27b, miR-181a, miR-146b-5p, miR-181d and miR-146a expression was verified using real-time RT-PCR in the parental and the five drug-resistant cell lines. In conclusion, the present study demonstrates that the differentially expressed miRNA profiles in these five drug-resistant HCC sublines could be useful to further investigate the association of miRNA expression with drug resistance in HCC.