The long noncoding RNA (lncRNA) H19 has been recently characterized as an oncogenic lncRNA in some tumors. However, the role of H19 in pancreatic ductal adenocarcinoma (PDAC) remains unclear. In this study, we found that not only the levels of H19 was overexpressed in PDAC compared with adjacent normal tissues, but also H19 expression was upregulated remarkably in primary tumors which subsequently metastasized, compared to those did not metastasis. Subsequently, the efficacy of knockdown of H19 by H19-small interfering RNA (siRNA) was evaluated in vitro, and we found that downregulation of H19 impaired PDAC cell invasion and migration. We further demonstrated that H19 promoted PDAC cell invasion and migration at least partially by increasing HMGA2-mediated epithelial-mesenchymal transition (EMT) through antagonizing let-7. This study suggests an important role of H19 in regulating metastasis of PDAC and provides some clues for elucidating the lncRNA-miRNA functional network in cancer.

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BackgroundmicroRNAs (miRNAs) are a class of small non-coding RNAs that play important roles in carcinogenesis. In the present study, we investigated the effect of miR-212 on pancreatic ductal adenocarcinoma (PDAC) and its target protein.MethodsQuantitative real-time PCR(qRT-PCR) was performed to detect the expression of miR-212 in PDAC tissues and pancreatic cancer cell lines. miR-212 mimic, miR-212 inhibitor and negative control were transfected into pancreatic cancer cells and the effect of miR-212 up-regulation and down-regulation on the proliferation, migration and invasion of cells were investigated. Furthermore, the mRNA and protein levels of Patched-1(PTCH1) were measured. Meanwhile, luciferase assays were performed to validate PTCH1 as miR-212 target in PDAC.ResultsmiR-212 was up-regulated in PDAC tissues and cells.Using both gain-of function and loss-of function experiments, a pro-oncogenic function of miR-212 was demonstrated in PDAC. Moreover, up-regulated of PTCH1 could attenuate the effect induced by miR-212.ConclusionThese data suggest that miR-212 could facilitate PDAC progression and metastasis through targeting PTCH1, implicating a novel mechanism for the progression of PDAC.

BackgroundThe dysregulation of oncogenes and tumor suppressor genes plays an important role in many cancers, including hepatocellular carcinoma (HCC), which is one of the most common cancers in the world. In a previous microarray experiment, we found that DLGAP5 is overexpressed in HCCs. However, whether the up-regulation of DLGAP5 contributes to hepatocarcinogenesis remains unclear. Methodology/Principal FindingsIn this study, we showed that DLGAP5 was significantly up-regulated in 76.4% (168 of 220) of the analyzed HCC specimens when compared with adjacent liver tissue. DLGAP5 overexpression was evident in 25% (22 of 88) of the HCC specimens without AFP expression, suggesting that DLGAP5 may be a novel biomarker for HCC pathogenesis. The silencing of DLGAP5 gene expression by RNA interference significantly suppressed cell growth, migration and colony formation in vitro. The expression level of DLGAP5 was also found to be related to the methylation level of its promoter in the HCC specimens. Conclusions/SignificanceTaken together, these data suggest that the expression of DLGAP5 is regulated by methylation and that the up-regulation of DLGAP5 contributes to HCC tumorigenesis by promoting cell proliferation.