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      MiR-19a, miR-122 and miR-223 are differentially regulated by hepatitis B virus X protein and involve in cell proliferation in hepatoma cells

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          Hepatitis B virus (HBV) X protein (HBx) is a type of oncogenic protein involved in the progression of hepatocellular carcinoma (HCC) via interacting with host genes. Dysregulation of microRNAs (miRNAs) has been observed in HCC. This study aimed to investigate the role of HBx protein in the regulation of miR-19a, miR-122 and miR-223, and examine if these miRNAs involve in progression of malignant hepatocytes.


          Quantitative real time PCR (qRT-PCR) was used to measure the expression of miR-19a, miR-122 and miR-223 in patient samples and in HepG2 cells transfected with HBx or 1.3 fold HBV genome and also in HepG2.2.15 cells, which stably produces HBV. Their target mRNAs and proteins-PTEN, cyclin G1 and c-myc were measured by qRT-PCR and western blot, respectively. The effect of miR-19a, miR-122 and miR-223, and their respective target genes, on cell proliferation was analyzed using 5-ethynyl-2-deoxyuridine incorporation and MTT assay.


          MiR-19a showed an up-regulation in HBV-positive HCC patients compared to healthy controls and HBV-negative HCC patients, while miR-122 and miR-223 showed a down-regulation compared to healthy controls, and miR-122 in HBV-positive HCC patients was also down-regulated when compared to HBV-negative HCC patients. MiR-19a was found to be up-regulated in HepG2 cells transfected with HBx or 1.3 fold HBV genome, but down-regulated in HepG2.2.15 cells. MiR-122 and miR-223 were down-regulated in HBx or 1.3 fold HBV transfected HepG2 cells as well as in HepG2.2.15 cell. Their target mRNAs and corresponding proteins-PTEN was down-regulated, while cyclin G1 and c-myc were found to be up-regulated. Modulated expression of miR-19a, miR-122 and miR-223 enhanced cell proliferation of HBx-transfected HepG2 cells, and rescue experiment further showed that their target genes-PTEN, cyclin G1and c-myc involved in cell proliferation of HBx-transfected HepG2 cells.


          The expression of miR-19a, miR-122 and miR-223 were differentially regulated by HBx protein, the differential expression of miR-19a, miR-122 and miR-223 plays an important role in cell proliferation of HCC. This study provides new insight into understanding how HBx protein interacts with miRNAs and subsequently regulates host function.

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          Most cited references 38

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          MicroRNA-223 is commonly repressed in hepatocellular carcinoma and potentiates expression of Stathmin1.

          Recent studies have emphasized causative links between microRNA (miRNA) deregulations and cancer development. In hepatocellular carcinoma (HCC), information on differentially expressed miRNA remained largely undefined. Array-based miRNA profiling was performed on HCC cells that were derived from chronic carriers of hepatitis B virus (HBV) and hepatitis C virus (HCV), and nonviral-associated patients. Specific microRNA (miR)-223 and miR-222 deregulations were verified in an independent series of tumors. The functional effect of miR-223 was examined further. An integrative analysis of messenger RNA (mRNA) array with in silico predictions defined potential downstream targets of miR-223. A luciferase reporter assay was conducted to confirm target association. Distinct up-regulations of miR-222, miR-221, and miR-31, and down-regulations of miR-223, miR-126, and miR-122a were identified. Further investigations suggested the highly deregulated miR-223 and miR-222 could unequivocally distinguish HCC from adjacent nontumoral liver, irrespective of viral associations (P
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            miRNA-223 promotes gastric cancer invasion and metastasis by targeting tumor suppressor EPB41L3.

             Y Nie,  Zheyi Han,  Jie Ding (2011)
            Traditional research modes aim to find cancer-specific single therapeutic target. Recently, emerging evidence suggested that some micro-RNAs (miRNA) can function as oncogenes or tumor suppressors. miRNAs are single-stranded, small noncoding RNA genes that can regulate hundreds of downstream target genes. In this study, we evaluated the miRNA expression patterns in gastric carcinoma and the specific role of miR-223 in gastric cancer metastasis. miRNA expression signature was first analyzed by real-time PCR on 10 paired gastric carcinomas and confirmed in another 20 paired gastric carcinoma tissues. With the 2-fold expression difference as a cutoff level, we identified 22 differential expressed mature miRNAs. Sixteen miRNAs were upregulated in gastric carcinoma, including miR-223, miR-21, miR-23b, miR-222, miR-25, miR-23a, miR-221, miR-107, miR-103, miR-99a, miR-100, miR-125b, miR-92, miR-146a, miR-214 and miR-191, and six miRNAs were downregulated in gastric carcinoma, including let-7a, miR-126, miR-210, miR-181b, miR-197, and miR-30aa-5p. After examining these miRNAs in several human gastric originated cell lines, we found that miR-223 is overexpressed only in metastatic gastric cancer cells and stimulated nonmetastatic gastric cancer cells migration and invasion. Mechanistically, miR-223, induced by the transcription factor Twist, posttranscriptionally downregulates EPB41L3 expression by directly targeting its 3'-untranslated regions. Significantly, overexpression of miR-223 in primary gastric carcinomas is associated with poor metastasis-free survival. These findings indicate a new regulatory mode, namely, specific miRNA, which is activated by its upstream transcription factor, could suppress its direct targets and lead to tumor invasion and metastasis. ©2011 AACR.
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              PTEN: Multiple Functions in Human Malignant Tumors

              PTEN is the most important negative regulator of the PI3K signaling pathway. In addition to its canonical, PI3K inhibition-dependent functions, PTEN can also function as a tumor suppressor in a PI3K-independent manner. Indeed, the PTEN network regulates a broad spectrum of biological functions, modulating the flow of information from membrane-bound growth factor receptors to nuclear transcription factors, occurring in concert with other tumor suppressors and oncogenic signaling pathways. PTEN acts through its lipid and protein phosphatase activity and other non-enzymatic mechanisms. Studies conducted over the past 10 years have expanded our understanding of the biological role of PTEN, showing that in addition to its ability to regulate proliferation and cell survival, it also plays an intriguing role in regulating genomic stability, cell migration, stem cell self-renewal, and tumor microenvironment. Changes in PTEN protein levels, location, and enzymatic activity through various molecular mechanisms can generate a continuum of functional PTEN levels in inherited syndromes, sporadic cancers, and other diseases. PTEN activity can indeed, be modulated by mutations, epigenetic silencing, transcriptional repression, aberrant protein localization, and post-translational modifications. This review will discuss our current understanding of the biological role of PTEN, how PTEN expression and activity are regulated, and the consequences of PTEN dysregulation in human malignant tumors.

                Author and article information

                J Transl Med
                J Transl Med
                Journal of Translational Medicine
                BioMed Central (London )
                5 May 2016
                5 May 2016
                : 14
                Department of Oncology, The Fifth Affiliated Hospital of Guangzhou Medical University, No.621, Gangwan Road, Huangpu District, Guangzhou, 510700 China
                © Yu et al. 2016

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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                hepatitis b virus x protein, micrornas, hepatocellular carcinoma, hepg2, pten, cyclin g1, c-myc


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