Background: Glioma has a poor prognosis, and is the most common primary and lethal primary malignant tumor in the central nervous system. Retinoic acid receptor-related orphan receptor A (RORA) is a member of the ROR subfamily of orphan receptors and plays an anti-tumor role in several cancers. Methods: A cell viability assay, the Edu assay, neurosphere formation assay, and xenograft experiments were used to detect the proliferative abilities of glioma cell line, glioma stem cells (GSCs). Western blotting, ELISAs, and luciferase reporter assays were used to detect the presence of possible microRNAs. Findings: Our study found for the first time that RORA was expressed at low levels in gliomas, and was associated with a good prognosis. RORA overexpression inhibited the proliferation and tumorigenesis of glioma cell lines and GSCs via inhibiting the TNF-a mediated NF-kB signaling pathway. In addition, microRNA-18a had a promoting effect on gliomas, and was the possible reason for low RORA expression in gliomas. Interpretation: RORA may be a promising therapeutic target in the treatment of gliomas.

Background Glioma is the most common and lethal primary brain tumor in adults, and angiogenesis is one of the key factors contributing to its proliferation, aggressiveness, and malignant transformation. However, the discovery of novel oncogenes and the study of its molecular regulating mechanism based on circular RNAs (circRNAs) may provide a promising treatment target in glioma. Methods Bioinformatics analysis, qPCR, western blotting, and immunohistochemistry were used to detect the expression levels of ISL2, miR-342–3p, circRNA ARF1 (cARF1), U2AF2, and VEGFA. Patient-derived glioma stem cells (GSCs) were established for the molecular experiments. Lentiviral-based infection was used to regulate the expression of these molecules in GSCs. The MTS, EDU, Transwell, and tube formation assays were used to detect the proliferation, invasion, and angiogenesis of human brain microvessel endothelial cells (hBMECs). RNA-binding protein immunoprecipitation, RNA pull-down, dual-luciferase reporter, and chromatin immunoprecipitation assays were used to detect the direct regulation mechanisms among these molecules. Results We first identified a novel transcription factor related to neural development. ISL2 was overexpressed in glioma and correlated with poor patient survival. ISL2 transcriptionally regulated VEGFA expression in GSCs and promoted the proliferation, invasion, and angiogenesis of hBMECs via VEGFA-mediated ERK signaling. Regarding its mechanism of action, cARF1 upregulated ISL2 expression in GSCs via miR-342–3p sponging. Furthermore, U2AF2 bound to and promoted the stability and expression of cARF1, while ISL2 induced the expression of U2AF2, which formed a feedback loop in GSCs. We also showed that both U2AF2 and cARF1 had an oncogenic effect, were overexpressed in glioma, and correlated with poor patient survival. Conclusions Our study identified a novel feedback loop among U2AF2, cARF1, miR-342–3p, and ISL2 in GSCs. This feedback loop promoted glioma angiogenesis, and could provide an effective biomarker for glioma diagnosis and prognostic evaluation, as well as possibly being used for targeted therapy.

Background: Glioma is the most common primary malignant tumor in the central nervous system with frequent hypoxia and angiogenesis. Limb-Bud and Heart (LBH) is a highly conserved transcription cofactor that participates in embryonic development and tumorigenesis. Methods: The conditioned media from LBH regulated human glioma cell lines and patient-derived glioma stem cells (GSCs) were used to treat the human brain microvessel endothelial cells (hBMECs). The function of LBH on angiogenesis were examined through methods of MTS assay, Edu assay, TUNEL assay, western blotting analysis, qPCR analysis, luciferase reporter assay and xenograft experiment. Findings: Our study found for the first time that LBH was overexpressed in gliomas and was associated with a poor prognosis. LBH overexpression participated in the angiogenesis of gliomas via the vascular endothelial growth factor A (VEGFA)-mediated extracellular signal-regulated kinase (ERK) signalling pathway in human brain microvessel endothelial cells (hBMECs). Rapid proliferation of gliomas can lead to tissue hypoxia and hypoxia inducible factor-1 (HIF-1) activation, while HIF-1 can directly transcriptionally regulate the expression of LBH and result in a self-reinforcing cycle. Interpretation: LBH may be a possible treatment target to break the vicious cycle in glioma treatment.

The miRNAs are small, non-coding RNAs that regulate various biological processes, including liver fibrosis. Hepatic stellate cells (HSCs) play a central role in the pathogenesis of liver fibrosis. By microarray profiling and real-time PCR, we noted that miR-31 expression in HSCs from rats, mice and humans was significantly increased during HSC activation in culture. Overall, miR-31 expression levels were unchanged in the whole-liver RNA extracts from fibrotic rat and human samples. Nevertheless, we found that miR-31 was particularly up-regulated in HSCs but not in hepatocytes during fibrogenesis. Thus, we hypothesized that miR-31 may mediate liver fibrosis. In the present study, we found that inhibition of miR-31 expression significantly inhibited HSC activation, whereas its over-expression obviously promoted HSC activation. Moreover, over-expression of miR-31 promoted HSC migration by enhancing matrix metalloproteinase (MMP)-2 expression whereas inhibition of miR-31 has an opposite effect. The biological function of miR-31 during HSC activation might be through targeting FIH1, a suppressor of hypoxia-inducible factor (HIF-1), because a knockdown of FIH1 by shRNA could mimic the effects of miR-31. In addition, primary rat HSCs were isolated and treated with different cytokines, such as transforming growth factor β (TGF-β), vascular endothelial growth factor and platelet-derived growth factor-BB, to evaluate upstream regulators of miR-31. We found that only TGF-β, a pivotal regulator in liver fibrosis, remarkably increased miR-31 expression in HSCs. And the effects of TGF-β on HSCs can be partially counteracted by inhibition of miR-31. In addition, chromatin immunoprecipitation experiments and the luciferase reporter assay demonstrated that Smad3, a major TGF-β-downstream transcription factor, stimulated the transcription activity of miR-31 by binding directly to miR-31's promoter. In conclusion, the miR-31/FIH1 pathway associates with liver fibrosis, perhaps by participation in the TGF-β/Smad3 signalling of HSCs.