MicroRNA 4651 regulates nonsense-mediated mRNA decay by targeting SMG9 mRNA

MicroRNA-mediated regulation of nonsense-mediated mRNA decay factors: Insights into microRNA prediction tools and profiling techniques

Nonsense-mediated mRNA decay (NMD) stands out as a prominent RNA surveillance mechanism within eukaryotes, meticulously overseeing both RNA abundance and integrity by eliminating aberrant transcripts. These defective transcripts are discerned through the concerted efforts of translating ribosomes, eukaryotic release factors (eRFs), and trans-acting NMD factors, with Up-Frameshift 3 (UPF3) serving as a noteworthy component. Remarkably, in humans, UPF3 exists in two paralogous forms, UPF3A (UPF3) and UPF3B (UPF3X). Beyond its role in quality control, UPF3 wields significant influence over critical cellular processes, including neural development, synaptic plasticity, and axon guidance. However, the precise regulatory mechanisms governing UPF3 remain elusive. MicroRNAs (miRNAs) emerge as pivotal post-transcriptional gene regulators, exerting substantial impact on diverse pathological and physiological pathways. This comprehensive review encapsulates our current understanding of the intricate regulatory nexus between NMD and miRNAs, with particular emphasis on the essential role played by UPF3B in neurodevelopment. Additionally, we bring out the significance of the 3'-untranslated region (3'-UTR) as the molecular bridge connecting NMD and miRNA-mediated gene regulation. Furthermore, we provide an in-depth exploration of diverse computational tools tailored for the prediction of potential miRNA targets. To complement these computational approaches, we delineate experimental techniques designed to validate predicted miRNA-mRNA interactions, empowering readers with the knowledge necessary to select the most appropriate methodology for their specific research objectives.

MicroRNA-4651 represses hepatocellular carcinoma cell growth and facilitates apoptosis via targeting FOXP4

MicroRNAs (miRNAs) belong to the subgroup of small noncoding RNAs, which typically serve as important gene regulators to participate in different biological events, such as tumor cell growth and apoptosis. Recent studies indicated microRNA-4651 (miR-4651) was involved in hepatocellular carcinoma (HCC) progression. The certain role of miRNA-4651 during the progression of HCC, however, remains unclear. Herein, we investigated the mRNA expression level of miR-4651 in HCC tissues and HCC cell lines and found miR-4651 was noticeably down-regulated compared with the normal liver tissues and QSG-7701 cell line, respectively. Then, miR-4561 overexpression obviously repressed the proliferation and promoted apoptosis in two HCC cell lines. Interestingly, we further identified that miR-4561 could directly interact with FOXP4 in HCC cells by using bio-informatic method and report assay. Moreover, forced expression of FOXP4 showed an opposite effect compared with miR-4561 in HCC cell lines. Hence, our findings strongly indicated that miR-4561 regulated the HCC cell growth and apoptosis mainly through targeting the FOXP4 genes. Clinically, the miR-4561/FOXP4 axis might be a potential target for therapeutic application of HCC patient treatment.

miR-4651 inhibits cell proliferation of gingival mesenchymal stem cells by inhibiting HMGA2 under nifedipine treatment

Drug-induced gingival overgrowth (DIGO) is recognized as a side effect of nifedipine (NIF); however, the underlying molecular mechanisms remain unknown. In this study, we found that overexpressed miR-4651 inhibits cell proliferation and induces G0/G1-phase arrest in gingival mesenchymal stem cells (GMSCs) with or without NIF treatment. Furthermore, sequential window acquisition of all theoretical mass spectra (SWATH-MS) analysis, bioinformatics analysis, and dual-luciferase report assay results confirmed that high-mobility group AT-hook 2 (HMGA2) is the downstream target gene of miR-4651. Overexpression of HMGA2 enhanced GMSC proliferation and accelerated the cell cycle with or without NIF treatment. The present study demonstrates that miR-4651 inhibits the proliferation of GMSCs and arrests the cell cycle at the G0/G1 phase by upregulating cyclin D and CDK2 while downregulating cyclin E through inhibition of HMGA2 under NIF stimulation. These findings reveal a novel mechanism regulating DIGO progression and suggest the potential of miR-4651 and HMGA2 as therapeutic targets.

MicroRNA-4651 targets bromodomain-containing protein 4 to inhibit non-small cell lung cancer cell progression

Bromodomain-containing protein 4 (BRD4) overexpression in non-small cell lung cancer (NSCLC) promotes cancer progression. Here, we show that miR-4651 selectively targets and negatively regulates BRD4 in A549 and primary human NSCLC cells. RNA pull-down experiments confirmed that miR-4651 directly binds to BRD4 mRNA. Further, ectopic overexpression of miR-4651 in A549 cells and primary NSCLC cells decreased BRD4 3'-UTR luciferase reporter activity and its expression, whereas miR-4651 inhibition elevated both. Functional studies demonstrated that NSCLC cell growth, proliferation, and migration were suppressed with ectopic miR-4651 overexpression but enhanced with miR-4651 inhibition. BRD4 re-expression using a 3'-UTR mutant BRD4 reversed A549 cell inhibition induced by miR-4651 overexpression. Further, miR-4651 overexpression or inhibition failed to alter the functions of BRD4-KO A549 cells. In vivo, miR-4651-overexpressing A549 xenografts grew slowly than control A549 xenografts in severe combined immunodeficient mice. Finally, miR-4651 was downregulated in human NSCLC tissues, correlating with BRD4 elevation. Together, miR-4651 targets BRD4 to inhibit NSCLC cell growth in vitro and in vivo.