Gene expression of VPA and GEM

Background: Histone deacetylase (HDAC) is strongly associated with epigenetic regulation and carcinogenesis, and its inhibitors induce the differentiation or apoptosis of cancer cells. Valproic acid (VPA) is one of the clinically available HDAC inhibitors. We investigated the anticancer effects of VPA in combination with gemcitabine (GEM) in cholangiocarcinoma cell line, and explored the mechanisms of the anticancer effects using microarray analysis. Methods: A human cholangiocarcinoma cell line (HuCCT1) was used. The anticancer effects of VPA, or gemcitabine (GEM), and the effects of VPA combined with GEM, were studied by cell proliferation assay. The microarray analysis was performed, the genes were picked up using Gene Spring GX11.5, Ingenuity Pathways Analysis (IPA) was performed, and then the gene-expression was determined by RT-PCR. Results: GEM (5nM) and VPA (0.5mM) reduced by 23%, which significantly augmented the anticancer effect of GEM alone or VPA alone (P<0.01). Using the microarray analysis, forty-three genes were identified with the comparison between GEM group and GEM plus VPA combination group. The interactions were shown between genes of the Cellular Development relevant to the differentiation of cancer cell using IPA.

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