Circ_SIPA1L1 Promotes Osteosarcoma Progression Via miR-379-5p/MAP3K9 Axis

Identification of Cardiac CircRNAs in Mice With CVB3-Induced Myocarditis

Background: Viral myocarditis could initiate various immune response to the myocardium, resulting in myocyte damage and subsequent cardiac dysfunction. The expression profile and functions of circRNAs in this process are unknown.

Methods: Fulminant myocarditis (FM) and non-FM models were induced by coxsackie B3 virus (CVB3) infection in A/J mice and C57BL/6 mice, respectively. CircRNAs expression profile was identified by RNA-seq. Quantitative RT-PCR, Spearman rank correlation, KEGG pathway, GO analysis, Western blot and flow cytometry were performed for functional analysis.

Results: Severer inflammatory cell infiltration and cardiomyocyte necrosis were presented in CVB3-treated A/J mice than those in C57BL/6 mice. The dysregulated circRNAs in both of the mouse strains displayed strong correlation with the immune response, but dysregulated circRNAs in A/J mice were more prone to cardiac dysfunction. KEGG analysis indicated that the target genes of dysregulated circRNAs in A/J mice were mainly involved in viral infection, T cell and B cell receptor signaling pathways, while the target genes of dysregulated circRNAs in C57BL/6 mice were unrelated to immune pathways. Furthermore, knockdown of circArhgap32 that was downregulated in CVB3-treated A/J mice promoted cardiomyocyte apoptosis in vitro.

Conclusion: Our data showed that cardiac circRNAs dysregulation is an important characteristic of viral myocarditis.

Blocking hsa_circ_0074027 suppressed non-small cell lung cancer chemoresistance via the miR-379-5p/IGF1 axis

Cancer cell chemoresistance is the primary reason behind cancer treatment failure. Previous reports suggest that circular RNA (circRNA) hsa_circ_0074027 (HC0074027) is a crucial modulator of non-small cell lung cancer (NSCLC) disease progression. Herein, we delineated the underlying mechanism of HC0074027-regulated chemoresistance in NSCLC. We employed quantitative real-time polymerase chain reaction (qRT-PCR) or Elisa in the detection of HC0074027, micoRNA-379-5p (miR-379-5p), and insuline-like growth factor I (IGF1) expressions. Cell survival was evaluated via the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Direct associations among HC0074027, miR-379-5p, and IGF1 were examined via dual-luciferase reporter (DLR) and RNA immunoprecipitation (RIP) assays. Lastly, HC0074027 was incorporated into nude mice to examine its biological activity in vivo. Based on our analysis, HC0074027 levels strongly correlated with NSCLC chemoresistance to docetaxel (DTX), cisplatin (DDP), and paclitaxel (PTX). Alternately, HC0074027 silencing enhanced chemosensitivity in vitro. In vivo, HC0074027 downregulation suppressed tumor expansion and increased cancer cell sensitivity to chemotherapy. We also revealed that HC0074027 physically interacts with miR-379-5p to exert its biological function in vitro. Moreover, IGF1 is a functionally crucial target of miR-379-5p in modulating NSCLC chemoresistance in vitro. Finally, we demonstrated that HC0074027 can indirectly modulate IGF1 levels via sequestering miR-379-5p. We demonstrated that HC0074027 promotes NSCLC chemoresistance via sequestering miR-379-5p activity, and modulating IGF1 expression. Our work highlights the significance of HC0074027 in NSCLC chemoresistance and suggests HC0074027 to be an excellent candidate for targeted NSCLC therapy.

An update on the role of miR-379 in human disorders

miR-379 is a miRNA transcribed from the MIR379 locus on 14q32.31. This miRNA is located in an evolutionarily conserved miRNA cluster in an imprinted region that contains DLK1 and DIO3 genes. The mouse homolog of this miRNA has been shown to be under-expressed in response to glucocorticoid receptor deficiency. Moreover, miR-379 has a tumor-suppressive role in a wide variety of tissues including the brain, breast, lung, and liver. In addition to restraining cell proliferation and migration, miR-379 can suppress the epithelial-mesenchymal transition process. Abnormal expression of this miRNA implies the pathogenesis of Duchene muscular dystrophy, spinal cord injury, diabetic nephropathy, acute myocardial infarction, and premature ovarian failure. This review aims to the summarization of the role of miR-379 in neoplastic and non-neoplastic conditions.