Long noncoding RNA CCAT2 promotes hepatocellular carcinoma proliferation and metastasis through up-regulation of NDRG1.

BACKGROUND: Emerging studies demonstrate that long noncoding RNAs (lncRNAs) play crucial roles in hepatocarcinogenesis through various mechanisms. LncRNA CCAT2 was a newly discovered lncRNA and amplified in several cancers. However, the mechanisms involved in function of CCAT2 in hepatocellular carcinoma (HCC) remain to be explored. METHODS: CCAT2 expressions in HCC tissues and cell lines were measured by RT-qPCR. MTS assay, colony formation assay, wound-healing assay and transwell assay were used to explore the biological functions of CCAT2 on HCC cells proliferation and metastasis. Experiments in vivo were carried out to confirm these effects. The underlying mechanisms were analyzed by western blot and dual-luciferase reporter assay. RESULTS: In this study, we found that CCAT2 were significantly elevated in HCC tissues and cell lines, and it promoted HCC cells proliferation and metastasis both in vitro and in vivo. Additionally, we identified that NDRG1 was a downstream target of CCAT2. Meanwhile, depletion of CCAT2 inhibited cellular proliferation and metastasis behaviors induced by NDRG1- overexpression. Analysis of mechanism underlying these effects revealed that CCAT2 increased the expression of NDRG1 by enhancing its promoter activity. Furthermore, the active region between CCAT2 and NDRG1 promoter was confirmed by dual-luciferase reporter assay. CONCLUSIONS: All these observations demonstrate that CCAT2 acts as an oncogene by up-regulating NDRG1, which may have the potential to be used as a promising prognostic biomarker and therapeutic target for HCC.

LINC00628 suppresses migration and invasion of hepatocellular carcinoma by its conserved region interacting with the promoter of VEGFA.

Accumulated evidence revealed that numerous long noncoding RNAs (lncRNAs) have been found to be involved in the development and progression of hepatocellular carcinoma (HCC). LINC00628, a member of lncRNAs, has been reported to act as a tumor suppressor in gastric cancer and breast cancer. However, its potential role in HCC still remains unknown. Herein, we characterized the function of LINC00628 in HCC. Our investigation has revealed that LINC00628 were dramatically decreased in HCC tissues and cells, and inhibited the migration and invasion of HCC cells in vitro and in vivo. Moreover, LINC00628 exerted its tumor suppressive function by repressing the vascular endothelial growth factor A (VEGFA) promoter activity. A highly conserved region element in LINC00628 was identified by a cross-species comparative analysis, which is required for LINC00628 exerted its function. Dual-luciferase reporter assay showed that the conserved sequence mediated the interaction with a specific region of VEGFA promoter, resulting in a decrease of VEGFA expression. In conclusion, our results demonstrated that LINC00628 could function as a tumor suppressor in HCC via its conserved sequence elements interacting with a particular region of VEGFA promoter, suggesting that LINC00628 may serve as a novel promising target for diagnosis and therapy in HCC.

An enzyme-free electrochemiluminescence biosensor for ultrasensitive assay of Group B Streptococci based on self-enhanced luminol complex functionalized CuMn-CeO2 nanospheres.

Herein, a novel and pragmatic electrochemiluminescence (ECL) biosensing method was developed for ultrasensitive and specific detection of Group B Streptococci (GBS) by combining self-enhanced luminol complex functionalized CuMn-CeO2 (CuMn-CeO2-PEI-luminol) with MNAzyme-mediated target-recycling amplification. First, the efficient self-enhanced PEI-luminol luminophore was prepared by combining PEI co-reactant with luminol in one molecular, which shortened electron transfer distance and enhanced ECL signal. And CuMn-CeO2 was applied to load a large number of PEI-luminol and strengthen luminous efficiency of luminol by the high catalytic activity toward H2O2 oxidation. Then, target-driven MNAzyme system was used to realize the circulation of GBS nucleic acid sequence, producing plentiful triggers to initiate the hybridization reaction on the surface of electrode. The developed enzyme-free ECL biosensor showed ultra-sensitivity for target DNA detection with detection limits of 68 aM (synthetic DNA) and 5 × 102 CFU mL-1 (genomic DNA extracted from GBS strain). More importantly, this biosensor was successfully applied for detection of genomic DNA of GBS extracted from clinical vaginal/anal swabs as low as 320 copies. Thus, this proposed strategy might be an pragmatic ECL platform for ultrasensitive and specific detection of GBS in clinical vaginal/anal swabs.

Long noncoding RNA MIR31HG inhibits hepatocellular carcinoma proliferation and metastasis by sponging microRNA-575 to modulate ST7L expression.

BACKGROUND: Emerging evidences have indicated that long noncoding RNAs (lncRNAs) play essential roles in the development and progression of cancers. Dysregulation of lncRNA MIR31HG has recently been reported in several types of cancers, and researches on the function of MIR31HG in cancers suggested that MIR31HG could act as either oncogene or tumor suppressor. But the functional involvement of MIR31HG has not been studied in hepatocellular carcinoma (HCC). METHODS: In this study, MTS assays, colony formation assay, Wound-healing assay, Transwell assy, and tumor xenografts experiments were used to identify biological effects of MIR31HG on HCC cells HCC proliferation and metastasis in vitro and in vivo. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to show the interactions of MIR31HG and miR-575. The bioinformatics methods were completed to find the target genes of miR-575. And Dual-luciferase reporter assay and Western blot analysis were further used to confirm the target gene of miR-575. RESULTS: We found that overexpression of MIR31HG obviously suppressed HCC proliferation and metastasis in vitro and in vivo, whereas knockdown of MIR31HG had the opposite effects. Besides, overexpression of MIR31HG significantly decreased the expression of microRNA-575 (miR-575), which plays an oncogenic role in HCC. Moreover, dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay revealed that MIR31HG exerted tumor-suppressive functions by binding directly to miR-575, and there was a reciprocal inhibition between MIR31HG and miR-575 in the same RNA-induced silencing complex (RISC). Furthermore, overexpression of MIR31HG enhanced the expression of suppression of tumorigenicity 7 like (ST7L), which was identified as a downstream target gene of miR-575. Thus, MIR31HG positively regulated ST7L expression through sponging miR-575, and acted as tumor suppressor in HCC. CONCLUSIONS: Overall, our study illuminates the role of MIR31HG as a miRNA sponge in HCC, and sheds new light on lncRNA-directed diagnostics and therapeutics in HCC.

LINC00052/miR-101-3p axis inhibits cell proliferation and metastasis by targeting SOX9 in hepatocellular carcinoma.

Long non-coding RNAs (lncRNAs) have emerged as critical regulators in a variety of diseases, including many tumors, such as hepatocellular carcinoma (HCC). However, the function and mechanisms responsible for these molecules in HCC are not thoroughly understood. In our previous study, we found that LINC00052 was acted as a tumor suppressor in HCC. In this study, we performed transcription microarray analysis to investigate the target gene of LINC00052, and found that knockdown of LINC00052 significantly increased the expression of SRY-related HMG-box gene 9 (SOX9), which plays an oncogenic role in HCC. Moreover, luciferase reporter assay revealed that LINC00052 promoted miR-101-3p expression by enhancing its promoter activity. In addition, online database analysis tools and luciferase assays showed that miR-101-3p could target SOX9. Quantitative real-time polymerase chain reaction (qRT-PCR) demonstrated that miR-101-3p was downregulated in HCC tissues and HCC cell lines. And we found a positive relationship between LINC00052 and miR-101-3p, and a negative relationship between miR-101-3p and SOX9 in HCC tissues. Besides, miR-101-3p was involved in LINC00052 inhibits HCC cells proliferation and metastasis. At the molecular level, LINC00052 downgulated SOX9 to inhibit HCC cells proliferation and metastasis by interacting with miR-101-3p. It might be a potential application for HCC therapy.