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Long non-coding RNAs (lncRNAs), which represent a new frontier in molecular biology, play important roles in regulating gene expression at epigenetic, transcriptional and post-transcriptional levels. More and more lncRNAs have been found to play important roles in normal cell physiological activities, and participate in the development of varieties of tumors and other diseases. Previously, we have only been able to determine the function of lncRNAs through multiple mechanisms, including genetic imprinting, chromatin remodeling, splicing regulation, mRNA decay, and translational regulation. Application of technological advances to research into the function of lncRNAs is extremely important. The major tools for exploring lncRNAs include microarrays, RNA sequencing (RNA-seq), Northern blotting, real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR), fluorescence in situ hybridization (FISH), RNA interference (RNAi), RNA-binding protein immunoprecipitation (RIP), chromatin isolation by RNA purification (ChIRP), crosslinking-immunopurification (CLIP), and bioinformatic prediction. In this review, we highlight the functions of lncRNAs, and advanced methods to research lncRNA-protein interactions.

Maternally Expressed Gene 3 (MEG3) encodes a lncRNA which is suggested to function as a tumor suppressor. Previous studies suggested that MEG3 functioned through activation of p53, however, the functional properties of MEG3 remain obscure and their relevance to human diseases is under continuous investigation. Here, we try to illuminate the relationship of MEG3 and p53, and the consequence in hepatoma cells. We find that transfection of expression construct of MEG3 enhances stability and transcriptional activity of p53. Deletion analysis of MEG3 confirms that full length and intact structure of MEG3 are critical for it to activate p53-mediated transactivation. Interestingly, our results demonstrate for the first time that MEG3 can interact with p53 DNA binding domain and various p53 target genes are deregulated after overexpression of MEG3 in hepatoma cells. Furthermore, results of qRT-PCR have shown that MEG3 RNA is lost or reduced in the majority of HCC samples compared with adjacent non-tumorous samples. Ectopic expression of MEG3 in hepatoma cells significantly inhibits proliferation and induces apoptosis. In conclusion, our data demonstrates that MEG3 functions as a tumor suppressor in hepatoma cells through interacting with p53 protein to activate p53-mediated transcriptional activity and influence the expression of partial p53 target genes.

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A novel approach involving the preparation of mannose-bearing chitosan microspheres with entrapping complexes of HBV DNA and PEI was developed to improve the delivery of DNA into antigen-presenting cells (APCs) after intramuscular (i.m.) injection. Compared with the traditional chitosan microspheres, the microspheres could quickly release intact and penetrative PEI/DNA complexes. What's more, chitosan was modified with mannose to target the primary APCs such as dendritic cells (DCs) owing to the high density of mannose receptors expressing on the surface of immature DCs. After i.m. immunization, the microspheres induced significantly enhanced serum antibody and cytotoxic T lymphocyte (CTL) responses in comparison to naked DNA.

BackgroundThousands of long noncoding RNAs (lncRNAs) have been reported in mammalian genomes. These RNAs represent an important subset of pervasive genes involved in a broad range of biological functions. Aberrant expression of lncRNAs is associated with many types of cancers. Here, in order to explore the potential lncRNAs involved in hepatocellular carcinoma (HCC) oncogenesis, we performed lncRNA gene expression profile analysis in 3 pairs of human HCC and adjacent non-tumor (NT) tissues by microarray.MethodologyDifferentially expressed lncRNAs and mRNAs were detected by human lncRNA microarray containing 33,045 lncRNAs and 30,215 coding transcripts. Bioinformatic analyses (gene ontology, pathway and network analysis) were applied for further study of these differentially expressed mRNAs. By qRT-PCR analysis in nineteen pairs of HCC and adjacent normal tissues, we found that eight lncRNAs were aberrantly expressed in HCC compared with adjacent NT tissues, which is consistent with microarray data.ConclusionsWe identified 214 lncRNAs and 338 mRNAs abnormally expressed in all three HCC tissues (Fold Change ≥2.0, P<0.05 and FDR <0.05) with the genome-wide lncRNAs and mRNAs expression profile analysis. The lncRNA-mRNA co-expression network was constructed, which may be used for predicting target genes of lncRNAs. Furthermore, we demonstrated for the first time that BC017743, ENST00000395084, NR_026591, NR_015378 and NR_024284 were up-regulated, whereas NR_027151, AK056988 and uc003yqb.1 were down-regulated in nineteen pairs of HCC samples compared with adjacent NT samples. Expression of seven lncRNAs was significantly correlated to their nearby coding genes. In conclusion, our results indicated that the lncRNA expression profile in HCC was significantly changed, and we identified a series of new hepatocarcinoma associated lncRNAs. These results provide important insights about the lncRNAs in HCC pathogenesis.

MicroRNAs may function to promote or suppress tumor development, depending on the cellular context. The important role of microRNAs in regulating molecular pathways underlying tumorigenesis has been emphasized in hepatocellular carcinoma (HCC). MicroRNAs regulate gene expression via post-transcriptional mechanisms by inhibiting translation or by degrading mRNA. In this study, we show that microRNA-1 (miR-1) and microRNA-499 (miR-499) are capable of repressing the expression of the ets1 proto-oncogene, which plays a fundamental role in the extracellular matrix (ECM) degradation, a process required for tumor cell invasion and migration. We used luciferase reporter assays to demonstrate that miR-1 and miR-499 target the 3' untranslated region (UTR) of ets1. Overexpression of miR-1 and miR-499 in HepG2 cells led to downregulation of ets1 mRNA and protein as assessed by quantitative reverse transcription PCR and western blot analysis. Furthermore, overexpression of miR-1 and miR-499 inhibited the invasion and migration of HepG2 cells in matrigel invasion and transwell migration assays, respectively. These results suggest that miR-1 and miR-499 may play an important role in the pathogenesis of HCC by regulating ets1.

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