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Epigenetic Regulation of PTEN in Hepatic Cancer
Author(s) -
Qadir Ximena Vanegas,
Han Chang,
Wu Tong
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1087.19
Subject(s) - pten , cancer research , dnmt1 , microbiology and biotechnology , biology , dna methylation , epigenetics , carcinogenesis , methylation , methyltransferase , cancer , gene expression , pi3k/akt/mtor pathway , gene , signal transduction , biochemistry , genetics
The pathogenesis of hepatocellular carcinoma (HCC) remains misunderstood offering limited therapeutic options for patients with hepatic cancer. Treatment of HCC cell line (Huh‐7) with DNMT inhibitor, Decitabine, and HDAC inhibitor, Trichostatin A, increased the expression of PTEN protein. Methylation‐specific qPCR assay showed Decitabine/TSA treatment resulted in hypermethylation of CpG islands located on the PTEN gene promoter. Furthermore, miR‐185 targets DNMT1, thus upregulating the expression of PTEN in Huh‐7. Forced overexpression of miR‐185 abolished the expression of DNMT1 protein and enhanced the level of PTEN protein in Huh‐7 stable cells. MiR‐185 xenograft tumor volume from SCID mice was significantly decreased versus control. Likewise, Ki‐67 immunostaining in Huh‐7 control stable cell line showed a higher proliferative. Xenograft protein samples showed increased PTEN expression and decreased DNMT1 activity. DNMT‐1 3'UTR reporter plasmids were constructed/cloned showing the wild type‐3'UTR of DNMT1 was significantly depleted in Huh‐7 miR‐185 stable cell line versus control in luciferase assay experiments. Co‐transfection of Huh‐7 miR‐185 ORF versus control showed DNMT1 restoration via western blot, Invasion and Cell Proliferation Assay. In‐situ hybridization showed a substantial decrease of staining expression in human HCC tumor samples versus normal liver tissue probed for miR‐185. Our results demonstrate a novel epigenetic regulation of PTEN by miR‐185, which is critical in hepatic carcinogenesis.