BackgroundLong noncoding RNA HULC is highly up-regulation in human hepatocellular carcinoma (HCC). However, the functions of HULC in hepatocarcinogenesis remains unclear.MethodsRT-PCR, Western blotting, Chromatin immunoprecipitation (CHIP) assay, RNA Immunoprecipitation (RIP) and tumorignesis test in vitro and in vivo were performed.ResultsHULC is negatively associated with expression of PTEN or miR15a in patients of human liver cancer. Moreover, HULC accelerates malignant progression of liver cancer cells in vitro and in vivo. Mechanistically, HULC increasesthe expression of P62 via decreasing mature miR15a. On the other hand, excessive HULC increases the expression of LC3 on the level of transcription and then activates LC3 through Sirt1 (a deacetylase). Notably, HULC enhanced the interplay between LC3 and ATG3. Furthermore, HULC also increases the expression of becline-1(autophagy related gene). Therefore, HULC increases the cellular autophagy by increasing LC3II dependent on Sirt1.Noteworthy, excessive HULC reduces the expression of PTEN, β-catenin and enhances the expression of SAPK/JUNK, PKM2, CDK2, NOTCH1, C-Jun in liver cancer cells. Of significance, our observations also revealed that HULC inhibited PTEN through ubiquitin–proteasome system mediated by autophagy-P62.Ultimately,HULC activates AKT-PI3K-mTOR pathway through inhibiting PTEN in human liver cancer cells.ConclusionsThis study elucidates a novel mechanism that lncRNA HULC produces a vital function during hepatocarcinogenesis.

Long non-coding RNA HOTAIR predicts negative tumor prognosis and exhibits oncogenic activity. Herein, we demonstrate HOTAIR promotes human liver cancer stem cell malignant growth through downregulation of SETD2. Mechanistically, HOTAIR reduces the recuritment of the CREB, P300, RNA polII onto the SETD2 promoter region that inhibits SETD2 expression and its phosphorylation. Thereby, the SETD2 binding capacity to substrate histone H3 is weakened, triggering a reduction of trimethylation on histone H3 thirty-sixth lysine, and thereby the H3K36me3–hMSH2-hMSH6-SKP2 complex is also decreased. Strikingly, the complex occupancy on chromosome is depressed, preventing from mismatch DNA repair. While reducing the degradation capacity of Skp2 for aging histone H3 bound to damaged DNA, the aging histone repair is impaired. Furthermore, that the damaged DNA escaped to repair can causes microsatellite instability(MSI) and abnormal expression of cell cycle related genes that may trigger the hepatocarcinogenesis. This study provides evidence for HOTAIR to promote tumorigenesis via downregulating SETD2 in liver cancer stem cells.

Maternally expressed gene 3 (MEG3) encodes an lncRNA which is suggested to function as a tumor suppressor and has been showed to involve in a variety of cancers. Herein, our findings demonstrate that MEG3 inhibits the malignant progression of liver cancer cells in vitro and in vivo. Mechanistically, MEG3 promotes the expression and maturition of miR122 which targets PKM2. Therefore, MEG3 decreases the expression and nuclear location of PKM2 dependent on miR122. Furthermore, MEG3 also inhibits CyclinD1 and C-Myc via PKM2 in liver cancer cells. On the other hand, MEG3 promotes β-catenin degradation through ubiquitin–proteasome system dependent on PTEN. Strikingly, MEG3 inhibits β-catenin activity through PKM2 reduction and PTEN increase. Significantly, we also found that excessive β-catenin abrogated the effect of MEG3 in liver cancer. In conclusion, our study for the first time demonstrates that MEG3 acts as a tumor suppressor by negatively regulating the activity of the PKM2 and β-catenin signaling pathway in hepatocarcinogenesis and could provide potential therapeutic targets for the treatment of liver cancer.

Cancer up-regulated drug resistant (CUDR) is a novel non-coding RNA gene. Herein, we demonstrate excessive CUDR cooperates with excessive CyclinD1 or PTEN depletion to accelerate liver cancer stem cells growth and liver stem cell malignant transformation in vitro and in vivo. Mechanistically, we reveal the decrease of PTEN in cells may lead to increase binding capacity of CUDR to CyclinD1. Therefore, CUDR-CyclinD1 complex loads onto the long noncoding RNA H19 promoter region that may lead to reduce the DNA methylation on H19 promoter region and then to enhance the H19 expression. Strikingly, the overexpression of H19 increases the binding of TERT to TERC and reduces the interplay between TERT with TERRA, thus enhancing the cell telomerase activity and extending the telomere length. On the other hand, insulator CTCF recruits the CUDR-CyclinD1 complx to form the composite CUDR-CyclinD1-insulator CTCF complex which occupancied on the C-myc gene promoter region, increasing the outcome of oncogene C-myc. Ultimately, excessive TERT and C-myc lead to liver cancer stem cell and hepatocyte-like stem cell malignant proliferation. To understand the novel functions of long noncoding RNA CUDR will help in the development of new liver cancer therapeutic and diagnostic approaches.

In this study, the presence of microRNAs in coconut water was identified by real-time polymerase chain reaction (PCR) based on the results of high-throughput small RNA sequencing. In addition, the differences in microRNA content between immature and mature coconut water were compared. A total of 47 known microRNAs belonging to 25 families and 14 new microRNAs were identified in coconut endosperm. Through analysis using a target gene prediction software, potential microRNA target genes were identified in the human genome. Real-time PCR showed that the level of most microRNAs was higher in mature coconut water than in immature coconut water. Then, exosome-like nanoparticles were isolated from coconut water. After ultracentrifugation, some particle structures were seen in coconut water samples using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate fluorescence staining. Subsequent scanning electron microscopy observation and dynamic light scattering analysis also revealed some exosome-like nanoparticles in coconut water, and the mean diameters of the particles detected by the two methods were 13.16 and 59.72 nm, respectively. In conclusion, there are extracellular microRNAs in coconut water, and their levels are higher in mature coconut water than in immature coconut water. Some exosome-like nanoparticles were isolated from coconut water, and the diameter of these particles was smaller than that of animal-derived exosomes.