CircRRAS2 promotes myogenic differentiation of bovine MuSCs and is a novel regulatory molecule of muscle development.

The proliferation and myogenic differentiation of muscle stem cells (MuSCs) are important factors affecting muscle development and beef quality. There is increasing evidence that circRNAs can regulate myogenesis. We found a novel circRNA, named circRRAS2 that is significantly upregulated in the differentiation phase of bovine MuSCs. Here, we aimed to determine its roles in the proliferation and myogenic differentiation of these cells. The results showed that circRRAS2 was expressed in several bovine tissues. CircRRAS2 inhibited MuSCs proliferation and promoted myoblast differentiation. In addition, chromatin isolation by using RNA purification and mass spectrometry in differentiated muscle cells identified 52 RNA-binding proteins that could potentially bind to circRRAS2, in order to regulate their differentiation. The results suggest that circRRAS2 could be a specific regulator of myogenesis in bovine muscle.HighlightsCircRRAS2 expression is higher in DM cells than in GM cells.CircRRAS2 could significantly inhibit the proliferation and apoptosis of bovine MuSCs.CircRRAS2 promotes the differentiation of bovine MuSCs into myotubes.CircRRAS2 may exert regulatory effects through multiple RNA binding proteins.

Nuclear FAM289-Galectin-1 interaction controls FAM289-mediated tumor promotion in malignant glioma.

BACKGROUND: FAM92A1-289(abbreviated FAM289) is recognized as one of the newly-discovered putative oncogenes. However, its role and molecular mechanisms in promoting cancer progression has not yet been elucidated. This study was performed to reveal its oncogenic functions and molecular mechanisms in human glioblastoma multiforme (GBM) cell models with knockdown or overexpression of FAM289 in vitro and in vivo. METHODS: To elucidate the molecular mechanisms underlying FAM289-mediated tumor progression, the protein-protein interaction between FAM289 and Galectin-1 was verified by co-immunoprecipitation, followed by an analysis of the expression and activity of Galectin-1-associated signaling molecules. Knockdown and overexpression of FAM289 in glioma cells were applied for investigating the effects of FAM289 on cell growth, migration and invasion. The determination of FAM289 expression was performed in specimens from various stages of human gliomas. RESULTS: FAM289-galectin-1 interaction and concomitant activation of the extracellular signal-regulated kinase (ERK) pathway participated in FAM289-mediated tumor-promoting function. Since the expression of DNA methyl transferase 1 (DNMT1) and DNA methyl transferase 3B (DNMT3B) was regulated by FAM289 in U251 and U87-MG glioma cells, Galectin-1 interaction with FAM289 may promote FAM289 protein into the cell nucleus and activate the ERK pathway, thereby upregulating DNMTs expression. Drug resistance tests indicated that FAM289-mediated TMZ resistance was through stem-like property acquisition by activating the ERK pathway. The correlation between FAM289, Galectin-1 expression and the clinical stage of gliomas was also verified in tissue samples from glioblastoma patients. CONCLUSIONS: Our results suggest that high expression of FAM289 in GBM tissues correlated with poor prognosis. FAM289 contributes to tumor progression in malignant glioma by interacting with Galectin-1 thereby promoting FAM289 protein translocation into the cell nucleus. FAM289 in the nucleus activated the ERK pathway, up regulated DNMTs expression and induced stem-like property gene expression which affects drug resistance of glioma cells to TMZ. This study provided functional evidence for FAM289 to be developed as a therapeutic target for cancer treatment.

The Tumor-promoting Effects of FAM92A1-289 in Cervical Carcinoma Cells.

BACKGROUND/AIM: FAM92A1-289 is recognized as one of the newly-discovered putative oncogenes. This study was performed to reveal its oncogenic functions in human cervical carcinoma cells. MATERIALS AND METHODS: The FAM92A1-289+ cell line was established with knock-in technique and selected by puromycin-resistance screening. Scratch assay, methylthiazol tetrazolium assay, colony forming assay and xenograft test were used to examine cell migration, cell proliferation, cell viability and tumor formation, respectively. RESULTS: FAM92A1-289+ cells showed higher migration rate (p<0.05), higher cell viability (p<0.01), higher colony formation and tumor growth. The FAM92A1-289 protein was pulled-down by antibodies against proliferating cell nuclear antigen (PCNA) in the co-immunoprecipitation assay. CONCLUSION: The up-regulated expression of FAM92A1-289 could facilitate cell migration, boost cell proliferation and promote colony formation in vitro and tumor growth in vivo. The interaction between FAM92A1-289 and PCNA was verified by co-immunoprecipitation. This study provided functional evidence for FAM92A1-289 to be developed as a therapeutic target for cancer treatment.

The application of mRNA-based gene transfer in mesenchymal stem cell-mediated cytotoxicity of glioma cells.

Since the tumor-oriented homing capacity of mesenchymal stem cells (MSCs) was discovered, MSCs have attracted great interest in the research field of cancer therapy mainly focused on their use as carries for anticancer agents. Differing from DNA-based vectors, the use of mRNA-based antituor gene delivery benefits from readily transfection and mutagenesis-free. However, it is essential to verify if mRNA transfection interferes with MSCs' tropism and their antitumor properties. TRAIL- and PTEN-mRNAs were synthesized and studied in an in vitro model of MSC-mediated indirect co-culture with DBTRG human glioma cells. The expression of TRAIL and PTEN in transfected MSCs was verified by immunoblotting analysis, and the migration ability of MSCs after anticancer gene transfection was demonstrated using transwell co-cultures. The viability of DBTRG cells was determined with bioluminescence, live/dead staining and real time cell analyzer. An in vivo model of DBTRG cell-derived xenografted tumors was used to verify the antitumor effects of TRAIL- and PTEN-engineered MSCs. With regard to the effect of mRNA transfection on MSCs' migration toward glioma cells, an enhanced migration rate was observed with MSCs transfected with all tested mRNAs compared to non-transfected MSCs (p<0.05). TRAIL- and PTEN-mRNA-induced cytotoxicity of DBTRG glioma cells was proportionally correlated with the ratio of conditioned medium from transfected MSCs. A synergistic action of TRAIL and PTEN was demonstrated in the current co-culture model. The immunoblotting analysis revealed the apoptotic nature of the cells death in the present study. The growth of the xenografted tumors was significantly inhibited by the application of MSCPTEN or MSCTRAIL/PTEN on day 14 and MSCTRAIL on day 28 (p<0.05). The results suggested that anticancer gene-bearing mRNAs synthesized in vitro are capable of being applied for MSC-mediated anticancer modality. This study provides an experimental base for further clinical anticancer studies using synthesized mRNAs.

Expression and purification recombinant antihypertensive peptide ameliorates hypertension in rats with spontaneous hypertension.

A highly efficient Escherichia coli expression system was established to obtain an appreciable quantity of antihypertensive peptide. The DNA-coding sequence for the Gly-Val-Tyr-Pro-His-Lys peptide was chemically synthesized and linked to form a ten-copy in tandem. It was cloned into the vector pET-15b and expressed in E. coli BL21 (DE3). The optimal conditions for maximal expression were verified and included the induction time and the concentration of isopropyl-ß-D-thiogalactopyranoside. The recombinant protein was purified by affinity chromatography to greater than 95% purity, and further purification was achieved by High-performance Liquid Chromatography after cleavage with trypsin. The product was identified by Electrospray Ionization-Mass Spectrometry. The antihypertensive effects of the recombinant AHP were investigated in spontaneously hypertensive rats. The in vivo results demonstrated that a single oral administration of this peptide in spontaneously hypertensive rats resulted in a significant reduction of systolic blood pressure at 2h. Systolic blood pressure was stabilized 4h later and remained at a low level for 24h. This study provides a practical method to develop the peptide into functional foods or drugs for the prevention and treatment of hypertension.