Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 cooperates with enhancer of zeste homolog 2 to promote hepatocellular carcinoma development by modulating the microRNA-22/Snail family transcriptional repressor 1 axis.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is an oncogenic long noncoding RNA that has been found to promote carcinogenesis and metastasis in many tumors. However, the underlying role of MALAT1 in the progression and metastasis of hepatocellular carcinoma (HCC) remains unclear. In this study, aberrantly elevated levels of MALAT1 were detected in both HCC specimens and cell lines. We found that knockdown of MALAT1 caused retardation in proliferation, migration, and invasion both in vivo and in vitro. Mechanistic investigations showed that Snail family transcriptional repressor 1 (SNAI1) is a direct target of microRNA (miR)-22 and that MALAT1 modulates SNAI1 expression by acting as a competing endogenous RNA for miR-22. Inhibition of miR-22 restored SNAI1 expression suppressed by MALAT1 knockdown. Furthermore, MALAT1 facilitated the enrichment of enhancer of zeste homolog 2 (EZH2) at the promoter region of miR-22 and E-cadherin, which was repressed by MALAT1 knockdown. Cooperating with EZH2, MALAT1 positively regulated SNAI1 by repressing miR-22 and inhibiting E-cadherin expression, playing a vital role in epithelial to mesenchymal transition. In conclusion, our results reveal a mechanism by which MALAT1 promotes HCC progression and provides a potential target for HCC therapy.

Chen S ，Wang G ，Tao K ，Cai K ，Wu K ，Ye L ，Bai J ，Yin Y ，Wang J ，Shuai X ，Gao J ，Pu J ，Li H ... -  《-》

miR-124-3p availability is antagonized by LncRNA-MALAT1 for Slug-induced tumor metastasis in hepatocellular carcinoma.

As an oncogene, long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) can promote tumor metastasis. Hyperexpression of MALAT1 has been observed in many malignant tumors, including hepatocellular carcinoma (HCC). However, the role and mechanism of MALAT1 in HCC remain unclear. Thirty human HCC and paracancerous tissue specimens were collected, and the human hepatoma cell lines Huh7 and HepG2 were cultured according to standard methods. MALAT1 and Snail family zinc finger (Slug) expression were measured by real-time PCR, immunohistochemistry, and western blotting. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay verified the direct interaction between miR-124-3p and Slug(SNAI2) or MALAT1. Wound healing and transwell assays were performed to examine invasion and migration, and a subcutaneous tumor model was established to measure tumor progression in vivo. MALAT1 expression was upregulated in HCC tissues and positively correlated with Slug expression. MALAT1 and miR-124-3p bind directly and reversibly to each other. MALAT1 silencing inhibited cell migration and invasion. miR-124-3p inhibited HCC metastasis by targeting Slug. MALAT1 regulates Slug through miR-124-3p, affecting HCC cell metastasis. Thus, the MALAT1/miR-124-3p/Slug axis plays an important role in HCC.

Cui RJ ，Fan JL ，Lin YC ，Pan YJ ，Liu C ，Wan JH ，Wang W ，Jiang ZY ，Zheng XL ，Tang JB ，Yu XG ... -  《Cancer Medicine》

MicroRNA-26a suppresses epithelial-mesenchymal transition in human hepatocellular carcinoma by repressing enhancer of zeste homolog 2.

Ma DN ，Chai ZT ，Zhu XD ，Zhang N ，Zhan DH ，Ye BG ，Wang CH ，Qin CD ，Zhao YM ，Zhu WP ，Cao MQ ，Gao DM ，Sun HC ，Tang ZY ... -  《Journal of Hematology & Oncology》

LncRNA TRERNA1 facilitates hepatocellular carcinoma metastasis by dimethylating H3K9 in the CDH1 promoter region via the recruitment of the EHMT2/SNAI1 complex.

Long non-coding RNAs (LncRNAs) play an important role in hepatocellular carcinoma development, however, as a crucial driver of hepatocellular carcinoma (HCC) metastasis, their functions in tumour metastasis remain largely unknown. The lncRNA TRERNA1 expression levels were detected in HCC by quantitative real-time PCR (qPCR). The function of TRERNA1 was examined by wound-healing assays, transwell assays and tail vein injection experiments. The potential regulatory mechanisms of TRERNA1 on its target genes were explored by ChIP, RIP, IP and WB assays. Elevated TRERNA1 levels promoted HCC cell migration and invasion in vitro and in vivo. TRERNA1 recruited EHMT2 to dimethylate H3K9 in the CDH1 promoter region. Furthermore, EHMT2 bound to SNAI1 to suppress CDH1 expression in HCC cells. After inhibiting TRERNA1, the expression level of CDH1 was restored and was involved in the regulation of the EHMT2/SNAI1 complex. The level of TRERNA1 was positively correlated with tumour metastasis and was negatively correlated with the expression of CDH1 in HCC tissues. For the first time, the current study reveals that TRERNA1 promotes cell metastasis and the invasion of HCC via the recruitment of EHMT2 and/or the EHMT2/SNAI1 complex to suppress CDH1. These data identify a novel mechanism that regulates TRERNA1 in metastatic HCC and provides a potential targeted therapy for HCC patients.

Song W ，Gu Y ，Lu S ，Wu H ，Cheng Z ，Hu J ，Qian Y ，Zheng Y ，Fan H ... -  《-》

Overexpression of the long non-coding RNA SPRY4-IT1 promotes tumor cell proliferation and invasion by activating EZH2 in hepatocellular carcinoma.

Increasing evidences have demonstrated that the dysregulation of long non-coding RNAs (lncRNAs) may act as an important role in tumor progression. The long non-coding RNA SPRY4 intronic transcript 1 (SPRY4-IT1) has been reported in some cancer including regulating cell growth, differentiation, apoptosis, and cancer progression. However, the expression and function of SPRY4-IT1 in the progression of hepatocellular carcinoma (HCC) remain largely unknown. The lncRNA SPRY4-IT1 was detected by quantitative real time PCR (qRT-PCR) in HCC cell lines, CCK8 cell proliferation and transwell invasion assays were performed to detect the GC cell proliferation and invasion abilities. The protein expression of E-cadherin, Vimentin and Twist1 was analyzed by Western blotting assays. Furthermore, RNA immunoprecipitation (RIP) and Chromatin immunoprecipitation (ChIP) assays were used to analyze potential molecular mechanism of SPRY4-IT1 in HCC cells. We found that SPRY4-IT1 was up-regulated in HCC cell lines. Further function analysis demonstrated that knockdown of SPRY4-IT1 significantly inhibited HCC cells proliferation and invasion, but over-expression of SPRY4-IT1 had the opposite effects on HCC cells in vitro. Moreover, our results also indicated that SPRY4-IT1 over-expression significantly promoted the epithelial-mesenchymal transition (EMT) by up-regulating the transcription factor Twist1 and EMT marker Vimentin and inhibited the E-cadherin expression in MHCC97L cell. Whereas, knockdown of SPRY4-IT1 suppressed the transcription factor Twist1 and EMT marker Vimentin and increased the E-cadherin expression in MHCC97H cells. Mechanisms investigations showed that SPRY4-IT1 interacted with the EZH2 and epigenetically repressed the E-cadherin expression. In vivo, we also demonstrated that the tumor growth was inhibited in SPRY4-IT1 knockdown group compared with the control group. These results suggested that lncRNA SPRY4-IT1 might be considered as a therapeutic target in HCC.

Zhou M ，Zhang XY ，Yu X 《-》