The present study aimed to identify the specific microRNAs (miRNAs/miRs) and their corresponding target genes involved in hepatocellular carcinomas (HCCs). Microarray analysis was performed to examine the miRNA expression profiles of four paired HCC and corresponding non-cancerous (N) liver tissues using 985 miRNA probes. The Human miRNA Target database was used to identify the target genes of differentially expressed miRNAs between the HCC and N tissues. The protein expression levels of target genes in the HCC tissues and cell lines were evaluated using western blotting. miRNA-mediated suppression of target gene expression was evaluated by transiently transfecting the miRNA into the HCC cell lines. Of the 985 miRNAs evaluated, four miRNAs were differentially expressed (three upregulated and one downregulated miRNAs). Of these four miRNAs, miRNA-527 was highly downregulated in the HCC tissues. Glypican-3 (GPC-3) was predicted as a target gene of miRNA-527. Western blotting revealed that GPC-3 protein is highly expressed in the HCC tissues and HCC cell lines compared with N and normal cell lines. Transfection with miR-527 resulted in suppression of GPC-3 protein expression in the Cos7 cells. Furthermore, transfection with miR-527 also inhibited the intrinsic expression of GPC-3 in the Huh-7 cell line. This indicated that miR-527 in the HCC tissues may be an important novel miRNA that targets the GPC-3 gene expression. GPC-3, whose expression is regulated by miR-527, may be involved in the development and progression of HCC.
Keywords: glypican 3; hepatocellular carcinoma; microRNA; microRNA-527; target gene.
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