BackgroundLong non-coding RNA (lncRNA) H19 has been reported to involve in many kinds of human cancers and functions as an oncogene. Our previous study found that H19 was over-expressed in gallbladder cancer (GBC) and was shown to promote tumor development in GBC. However, the competing endogenous RNA (ceRNA) regulatory network involving H19 in GBC progression has not been fully elucidated. We aim to detect the role of H19 as a ceRNA in GBC.Methods and ResultsIn this study, the expression of H19 and miR-342-3p were analyzed in 35 GBC tissues and matched normal tissues by using quantitative polymerase chain reaction (qRT-PCR). We demonstrated H19 was overexpressed and negatively correlated with miR-342-3p in GBC. By dual-luciferase reporter assays, RNA-binding protein immunoprecipitation (RIP) and RNA pull-down assays, we verified that H19 was identified as a direct target of miR-342-3p. QRT-PCR and Western-blotting assays demonstrated that H19 silencing down-regulated, whereas over-expression enhanced the expression of miR-342-3p targeting FOXM1 through competitively ‘sponging’ miR-342-3p. Furthermore, transwell invasion assays and cell cycle assays indicated that H19 knockdown inhibited both cells invasion and proliferation, but this effects was attenuated by co-transfection of siRNA-H19 and miR-342-3p inhibitor in GBC cells. In vivo, tumor volumes were decreased significantly in H19 silenced group compared to the control group, but was attenuated by co-transfection of shRNA-H19 and miR-342-3p inhibitor, which were stablely constructed through lenti-virus vector.ConclusionOur results suggest a potential ceRNA regulatory network involving H19 regulates FOXM1 expression by competitively binding endogenous miR-342-3p in GBC. This mechanism may contribute to a better understanding of GBC pathogenesis and provides potential therapeutic strategy for GBC.

Gallbladder carcinoma (GBC) is an aggressive neoplasm, and the treatment options for advanced GBC are limited. Recently, long non‐coding RNAs (lncRNAs) have emerged as new gene regulators and prognostic markers in several cancers. In this study, we found that metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1) expression was up‐regulated in GBC tissues (P < 0.05). Luciferase reporter assays and RNA pull down assays showed that MALAT1 is a target of miR‐363‐3p. Real‐time quantitative PCR and Western blot analysis indicated that MALAT1 regulated Myeloid cell leukaemia‐1 (MCL‐1) expression as a competing endogenous RNA (ceRNA) for miR‐363‐3p in GBC cells. Furthermore, MALAT1 silencing decreased GBC cell proliferation and the S phase cell population and induced apoptosis in vitro. In vivo, tumour volumes were significantly decreased in the MALAT1 silencing group compared with those in the control group. These data demonstrated that the MALAT1/miR‐363‐3p/MCL‐1 regulatory pathway controls the progression of GBC. Inhibition of MALAT1 expression may be to a novel therapeutic strategy for gallbladder cancer.

Gallbladder cancer (GBC) is a highly malignant cancer with poor prognosis. Although long noncoding RNA (lncRNA) H19 has been reported to play vital role in many human cancers, whether it is involved in GBC proliferation is still unknown. This study was designed to explore the effect of H19 in GBC cell proliferation. The expression of H19 and AKT2 were significantly elevated in GBC tissues, and the level of miR-194-5p is markedly decreased. Moreover, the RNA levels of H19 and AKT2 were positively correlated, and H19 elevation was significantly associated with tumor size. Cell proliferation decreased significantly after knockdown of H19 in GBC-SD and NOZ cells and after knockdown of AKT2 in NOZ cells. Results from cell cycle studies indicated that the S phase were significantly decreased after knockdown of H19 in NOZ cells but significantly elevated after overexpression of H19 in GBC-SD cells. Furthermore, knockdown of H19 upregulated miR-194-5p levels, yet significantly decreased miR-194-5p targeting AKT2 gene expression in NOZ cells. Inhibitor against miR-194-5p reversed these effects. In addition, overexpression of H19 in GBC-SD cells downregulated miR-194-5p and markedly increased AKT2 expression, and miR-194-5p mimic reversed these effects. Eventually, GBC cells were arrested in G0/G1-phase after H19 knockdown, inhibition of miR-194-5p markedly promoted cells into S-phase and co-transfection of siH19, and miR-194-5p inhibitor exerted mutually counter-regulated effects on cell cycle. These results suggested that H19/miR-194-5p/AKT2 axis regulatory network might modulate cell proliferation in GBC.

Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (Malat1) functions as an oncogene in many types of human cancer. In this study, we show that Malat1 is overexpressed in gallbladder cancer (GBC) tissue and cells. The high Malat1 levels correlated positively with tumor size and lymphatic metastasis, and correlated negatively with overall survival. We also show that Malat1 functions as a competing endogenous RNA (ceRNA) for miR-206. Because miR-206 directly suppresses expression of ANXA2 and KRAS, which are thought to promote GBC progression, Malat1 binding of miR-206 in GBC tissue and cells has an oncogenic effect. Conversely, Malat1 knockdown inhibits proliferation and invasion by GBC cells while increasing apoptosis. In vivo, silencing Malat1 decreases tumor volume. These results suggest Malat1 could potentially serve as a therapeutic target and prognostic marker for GBC.

LncRNA-ROR has been reported to be involved in many kinds of human cancers. However, whether LncRNA-ROR is involved in gallbladder cancer progression remains largely unknown. The objective of this study is to investigate the role of LncRNA-ROR in gallbladder cancer. We found that LncRNA-ROR expression level was upregulated in gallbladder cancer tissues (P < 0.05) and was significantly associated with tumor sizes (P < 0.05) and lymph node metastasis (P < 0.05). High expression of LncRNA-ROR was significantly associated with poor prognosis in gallbladder cancer patients (P < 0.05). Moreover, knockdown of LncRNA-ROR inhibited cell proliferation, migration, and invasion. The epithelial-mesenchymal transition (EMT) phenotype induced by TGF-β1 was reversed after LncRNA-ROR knocking down in SGC-996 and Noz cells. LncRNA-ROR plays an important role in the development of gallbladder cancer and mediates the EMT in gallbladder cancer. LncRNA-ROR might act as a marker of prognosis and therapeutic target for gallbladder cancer.

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The expression pattern and biological role of long non-coding RNA (lncRNA) in cancer has been reported to be involved in many cancers. Here, we report the expression and biological role of a newly discovered lncRNA NmrA-like family domain containing 1 pseudogene (Loc344887) in gallbladder cancer (GBC). In this study, we found that the expression of Loc344887 was significantly elevated in GBC tissues and cell lines when compared with matched normal tissues and normal epithelial bile duct cell line, respectively. High Loc344887 was associated with larger tumor size. Loc344887 was upregulated significantly after ectopic expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in GBC cells. Downregulation of Loc344887 in GBC cells suppressed cell proliferation, blocked cells in G0/S phase, and decreased the migration and invasion cell numbers. In addition, downregulation of Loc344887 decreased the expression of transcription factor Twist, mesenchymal marker Vimentin, and N-cadherin and increased the expression of epithelial maker E-cadherin, which could prompt a mesenchymal-to-epithelial transition phenotype. These results demonstrated that Loc344887 might contribute to cell proliferation and epithelial-to-mesenchymal transition process in GBC, which might be a potential therapeutic target.