Neuro-oncological ventral antigen 1 (NOVA1): Implications in neurological diseases and cancers

Unraveling the MicroRNA tapestry: exploring the molecular dynamics of locoregional recurrent rectal cancer

Introduction

Colorectal cancer (CRC) ranks as the third most prevalent malignancy globally, with a concerning rise in incidence among young adults. Despite progress in understanding genetic predispositions and lifestyle risk factors, the intricate molecular mechanisms of CRC demand exploration. MicroRNAs (miRNAs) emerge as key regulators of gene expression and their deregulation in tumor cells play pivotal roles in cancer progression.

Methods

NanoString's nCounter technology was utilized to measure the expression of 827 cancer-related miRNAs in tumor tissue and adjacent non-involved normal colon tissue from five patients with locoregional CRC progression. These expression profiles were then compared to those from the primary colon adenocarcinoma (COAD) cohort in The Cancer Genome Atlas (TCGA).

Results and discussion

Intriguingly, 156 miRNAs showed a contrasting dysregulation pattern in reccurent tumor compared to their expression in the TCGA COAD cohort. This observation implies dynamic alterations in miRNA expression patterns throughout disease progression. Our exploratory study contributes to understanding the regulatory landscape of recurrent CRC, emphasizing the role of miRNAs in disease relapse. Notable findings include the prominence of let-7 miRNA family, dysregulation of key target genes, and dynamic changes in miRNA expression patterns during progression. Univariate Cox proportional hazard models highlighted miRNAs associated with adverse outcomes and potential protective factors. The study underscores the need for more extensive investigations into miRNA dynamics during tumor progression and the value of stage specific biomarkers for prognosis.

RNA-binding protein NOVA1 promotes acute T-lymphocyte leukemia progression by stabilizing USP44 mRNA

Acute T-lymphocyte leukemia (T-ALL) is a malignant tumor disease. RNA-binding protein neotumor ventral antigen-1 (NOVA1) is highly expressed in bone marrow mononuclear cells of T-ALL patients, while the role of NOVA1 in T-ALL progression remains unknown. The gain- and loss-of-function studies for NOVA1 were performed in Jurkat and CCRF-CEM cells. NOVA1 overexpression promoted cell proliferation and cell cycle progression. NOVA1 knockdown increased the apoptosis rate of T-ALL cells. Ubiquitin-specific protease 44 (USP44), a nuclear protein with deubiquitinase catalytic activity, has been reported to play an oncogene role in human T-cell leukemia. USP44 expression was positively associated with NOVA1, and RNA immunoprecipitation assay verified the binding of NOVA1 to the mRNA of USP44. USP44 knockdown partially abolished NOVA1-induced cell proliferation and inhibition of apoptosis. The in vivo xenograft experiment was performed by injection of T-ALL tumor cells into the tail vein of NOD/SCID mice. The knockdown of NOVA1 had lower tumorigenicity. NOVA1 knockdown alleviated pathological changes in lung and spleen tissues, and increased the overall survival period and the weight of T-ALL mice. Thus, NOVA1 acts as an accelerator in T-ALL, and its function might be achieved by binding to and stabilizing USP44 mRNA.

Identifying potential pathogenesis and immune infiltration in diabetic foot ulcers using bioinformatics and in vitro analyses

BACKGROUND

Diabetic foot ulcers (DFU) are among the fastest-growing diseases worldwide. Recent evidence has emphasized the critical role of microRNA (miRNA)-mRNA networks in various chronic wounds, including DFU. In this study, we aimed to clarify the miRNA-mRNA axes associated with the occurrence of DFU.

METHODS

Expression profiles of miRNAs and mRNAs were extracted from the Gene Expression Omnibus. Differentially expressed genes and differentially expressed miRNAs were identified, and miRNA-mRNA regulatory axes were constructed through integrated bioinformatics analyses. We validated the miRNA-mRNA axes using quantitative real-time PCR (qPCR) and dual-luciferase reporter assays. We conducted an immune infiltration analysis and confirmed the bioinformatics results using immunofluorescence staining. Single-sample gene set enrichment analysis (ssGSEA) was used to analyze the metabolic mechanisms.

RESULTS

miR-182-5p-CHL1/MITF and miR-338-3p-NOVA1 interactions were identified using in silico analysis. The qPCR results showed apparent dysregulation of these miRNA-mRNA axes in DFU. The dual-luciferase reporter assay confirmed that miR-182-5p targeted CHL1 and MITF, and miR-338-3p targeted NOVA1. We conducted an immune infiltration analysis and observed that key genes correlated with decreased infiltration of M1 macrophages and resting mast cells in DFU. Immunofluorescence staining verified the co-localization of CHL1 and tryptase, while MITF and CD68 showed weak positive correlations. Metabolic pathways related to these three genes were identified using ssGSEA.

CONCLUSIONS

In summary, the miR-182-5p-CHL1/MITF and miR-338-3p-NOVA1 pathway interactions and decreased infiltration of M1 macrophages and resting mast cells may provide novel clues to the pathogenesis of DFU.

TRIAL REGISTRATION

The clinical trial included in this study was registered in the Chinese Clinical Trial Registry ( ChiCTR2200066660 ) on December 13, 2022.

GC-biased gene conversion drives accelerated evolution of ultraconserved elements in mammalian and avian genomes

Ultraconserved elements (UCEs) are the most conserved regions among the genomes of evolutionarily distant species and are thought to play critical biological functions. However, some UCEs rapidly evolved in specific lineages, and whether they contributed to adaptive evolution is still controversial. Here, using an increased number of sequenced genomes with high taxonomic coverage, we identified 2191 mammalian UCEs and 5938 avian UCEs from 95 mammal and 94 bird genomes, respectively. Our results show that these UCEs are functionally constrained and that their adjacent genes are prone to widespread expression with low expression diversity across tissues. Functional enrichment of mammalian and avian UCEs shows different trends indicating that UCEs may contribute to adaptive evolution of taxa. Focusing on lineage-specific accelerated evolution, we discover that the proportion of fast-evolving UCEs in nine mammalian and 10 avian test lineages range from 0.19% to 13.2%. Notably, up to 62.1% of fast-evolving UCEs in test lineages are much more likely to result from GC-biased gene conversion (gBGC). A single cervid-specific gBGC region embracing the uc.359 allele significantly alters the expression of Nova1 and other neural-related genes in the rat brain. Combined with the altered regulatory activity of ancient gBGC-induced fast-evolving UCEs in eutherians, our results provide evidence that synergy between gBGC and selection shaped lineage-specific substitution patterns, even in the most constrained regulatory elements. In summary, our results show that gBGC played an important role in facilitating lineage-specific accelerated evolution of UCEs, and further support the idea that a combination of multiple evolutionary forces shapes adaptive evolution.

Spliceosomic dysregulation unveils NOVA1 as a candidate actionable therapeutic target in pancreatic neuroendocrine tumors

Dysregulation of the splicing machinery is emerging as a hallmark in cancer due to its association with multiple dysfunctions in tumor cells. Inappropriate function of this machinery can generate tumor-driving splicing variants and trigger oncogenic actions. However, its role in pancreatic neuroendocrine tumors (PanNETs) is poorly defined. In this study we aimed to characterize the expression pattern of a set of splicing machinery components in PanNETs, and their relationship with aggressiveness features. A qPCR-based array was first deployed to determine the expression levels of components of the major (n = 13) and minor spliceosome (n = 4) and associated splicing factors (n = 27), using a microfluidic technology in 20 PanNETs and non-tumoral adjacent samples. Subsequently, in vivo and in vitro models were applied to explore the pathophysiological role of NOVA1. Expression analysis revealed that a substantial proportion of splicing machinery components was altered in tumors. Notably, key splicing factors were overexpressed in PanNETs samples, wherein their levels correlated with clinical and malignancy features. Using in vivo and in vitro assays, we demonstrate that one of those altered factors, NOVA1, is tightly related to cell proliferation, alters pivotal signaling pathways and interferes with responsiveness to drug treatment in PanNETs, suggesting a role for this factor in the aggressiveness of these tumors and its suitability as therapeutic target. Altogether, our results unveil a severe alteration of the splicing machinery in PanNETs and identify the putative relevance of NOVA1 in tumor development/progression, which could provide novel avenues to develop diagnostic biomarkers and therapeutic tools for this pathology.

Electroacupuncture at PC6 (Neiguan) Attenuates Angina Pectoris in Rats with Myocardial Ischemia-Reperfusion Injury Through Regulating the Alternative Splicing of the Major Inhibitory Neurotransmitter Receptor GABRG2

Angina pectoris is the most common manifestation of coronary heart disease, causing suffering in patients. Electroacupuncture at PC6 can effectively alleviate angina by regulating the expression of genes, whether the alternative splicing (AS) of genes is affected by acupuncture is still unknown. We established a rat model of myocardial ischemia-reperfusion by coronary artery ligation and confirmed electroacupuncture alleviated the abnormal discharge caused by angina pectoris measured in EMG electromyograms. Analysis of the GSE61840 dataset established that AS events were altered after I/R and regulated by electroacupuncture. I/R decreased the expression of splicing factor Nova1 while electroacupuncture rescued it. Further experiments in dorsal root ganglion cells showed Nova1 regulated the AS of the GABRG2, specifically on its exon 9 where an important phosphorylation site is present. In vivo, results also showed that electroacupuncture can restore AS of GABRG2. Our results proved that electroacupuncture alleviates angina results by regulating alternative splicing.

Reintroduction of the archaic variant of NOVA1 in cortical organoids alters neurodevelopment

The evolutionarily conserved splicing regulator neuro-oncological ventral antigen 1 (NOVA1) plays a key role in neural development and function. NOVA1 also includes a protein-coding difference between the modern human genome and Neanderthal and Denisovan genomes. To investigate the functional importance of an amino acid change in humans, we reintroduced the archaic allele into human induced pluripotent cells using genome editing and then followed their neural development through cortical organoids. This modification promoted slower development and higher surface complexity in cortical organoids with the archaic version of NOVA1 Moreover, levels of synaptic markers and synaptic protein coassociations correlated with altered electrophysiological properties in organoids expressing the archaic variant. Our results suggest that the human-specific substitution in NOVA1, which is exclusive to modern humans since divergence from Neanderthals, may have had functional consequences for our species' evolution.

Inhibition of miR-96-5p in the mouse brain increases glutathione levels by altering NOVA1 expression

Glutathione (GSH) is an important antioxidant that plays a critical role in neuroprotection. GSH depletion in neurons induces oxidative stress and thereby promotes neuronal damage, which in turn is regarded as a hallmark of the early stage of neurodegenerative diseases. The neuronal GSH level is mainly regulated by cysteine transporter EAAC1 and its inhibitor, GTRAP3-18. In this study, we found that the GTRAP3-18 level was increased by up-regulation of the microRNA miR-96-5p, which was found to decrease EAAC1 levels in our previous study. Since the 3'-UTR region of GTRAP3-18 lacks the consensus sequence for miR-96-5p, an unidentified protein should be responsible for the intermediate regulation of GTRAP3-18 expression by miR-96-5p. Here, we discovered that RNA-binding protein NOVA1 functions as an intermediate protein for GTRAP3-18 expression via miR-96-5p. Moreover, we show that intra-arterial injection of a miR-96-5p-inhibiting nucleic acid to living mice by a drug delivery system using microbubbles and ultrasound decreased the level of GTRAP3-18 via NOVA1 and increased the levels of EAAC1 and GSH in the dentate gyrus of the hippocampus. These findings suggest that the delivery of a miR-96-5p inhibitor to the brain would efficiently increase the neuroprotective activity by increasing GSH levels via EAAC1, GTRAP3-18 and NOVA1.

Splicing factors: Insights into their regulatory network in alternative splicing in cancer

More than 95% of all human genes are alternatively spliced after transcription, which enriches the diversity of proteins and regulates transcript and/or protein levels. The splicing isoforms produced from the same gene can manifest distinctly, even exerting opposite effects. Mounting evidence indicates that the alternative splicing (AS) mechanism is ubiquitous in various cancers and drives the generation and maintenance of various hallmarks of cancer, such as enhanced proliferation, inhibited apoptosis, invasion and metastasis, and angiogenesis. Splicing factors (SFs) play pivotal roles in the recognition of splice sites and the assembly of spliceosomes during AS. In this review, we mainly discuss the similarities and differences of SF domains, the details of SF function in AS, the effect of SF-driven pathological AS on different hallmarks of cancer, and the main drivers of SF expression level and subcellular localization. In addition, we briefly introduce the application prospects of targeted therapeutic strategies, including small-molecule inhibitors, siRNAs and splice-switching oligonucleotides (SSOs), from three perspectives (drivers, SFs and pathological AS). Finally, we share our insights into the potential direction of research on SF-centric AS-related regulatory networks.

Holistic insights into meningitic Escherichia coli infection of astrocytes based on whole transcriptome profiling

Aim: To investigate the mRNAs and noncoding RNAs (ncRNAs) expression in astrocytes upon meningitic-Escherichia coli infection. Materials & methods: The transcription of mRNAs and ncRNAs were fully investigated and profiled by whole transcriptome sequencing and bioinformatic approaches. Whole transcriptome differences between the infected astrocytes and brain microvascular endothelial cells were further compared and characterized. Results: A total of 2045 mRNAs, 74 long noncoding RNAs, 27 miRNAs and 418 circular RNAs were differentially transcribed in astrocytes upon infection. Competing endogenous RNAs regulatory networks were constructed and preliminary validated. Transcriptomic differences between astrocyte and brain microvascular endothelial cells revealed the cell-specific responses against the infection. Conclusion: Our study comprehensively characterized the ncRNAs and mRNAs profiles in astrocytes upon meningitic-E. coli infection, which will facilitate future functional studies.

NOVA1 expression is associated with clinicopathological characteristics and prognosis in patients with small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is a highly aggressive lung malignancy which is characteristic of rapid tumor proliferation, metastasis as well as paraneoplastic neurological syndromes (PNS). Recent studies have shown that neuro-oncological ventral antigen-1 (NOVA1) plays a crucial role in the progression of various tumors. However, its effect on SCLC is still exclusive. This study was aimed to explore NOVA1 expression in tumor tissues of SCLC patients as well as its correlation with clinicopathological characteristics and cancer-specific overall survivals.

METHODS

In this study, the patients pathologically diagnosed with new primary SCLC were enrolled. Firstly, we compared NOVA1 expression in SCLC tissues and adjacent normal tissues by immunohistochemistry. We further investigated the association of NOVA1 expression with clinicopathological markers (especially the categories of PNS) and survival time in SCLC patients.

RESULTS

Our finding exhibited that NOVA1 was remarkably expressed in SCLC tumorous tissues compared with adjacent normal lung tissues (P<0.001). Additionally, NOVA1 expression was closely associated with clinicopathological characteristics in SCLC patients in terms of tumor staging(χ2=15.833; P<0.001), lymph node metastasis (χ2=9.624; P=0.002), brain metastasis (χ2=9.624; P=0.002) and PNS (χ2=5.004; P=0.024). With the COX proportional hazard regression model, we detected that high expression of NOVA1 (HR =0.445; 95% CI: 0.213-0.934; P=0.032) was an independent factor for shorter survival time.

CONCLUSIONS

High expression of NOVA1 is closely associated with aggressive clinicopathological characteristics including PNS as well as poor survival in SCLC patients. NOVA1 can be served as a promising predictive factor for prognosis in SCLC.

Identification of NOVA family proteins as novel β-catenin RNA-binding proteins that promote epithelial-mesenchymal transition

The NOVA (neuro-oncological ventral antigen) protein family, composed of two paralogs, NOVA1 and NOVA2, consists of RNA-binding proteins involving in processes such as alternative splicing and transport of some target mRNAs. The function of NOVA has been well studied, and increasing evidence has shown that NOVA proteins may be important contributors to carcinogenesis. However, the molecular mechanisms underlying the roles of NOVA proteins in carcinogenesis remain to be determined. Here, we have identified both NOVA1 and NOVA2 as novel β-catenin RNA-binding proteins. The NOVA1/NOVA2 heterodimer positively regulates β-catenin expression by enhancing β-catenin mRNA stability. Furthermore, we demonstrated that NOVA1 and NOVA2 promote epithelial-mesenchymal transition via β-catenin in breast cancer cells, as NOVA-induced upregulation of epithelial and mesenchymal marker expression was attenuated by restoring β-catenin expression. Our results advance the current understanding of β-catenin post-transcriptional regulation and shed light on the role of NOVA proteins in cancer, suggesting that NOVA proteins are potential therapeutic targets in breast cancer.

Alternative Splicing by NOVA Factors: From Gene Expression to Cell Physiology and Pathology

NOVA1 and NOVA2, the two members of the NOVA family of alternative splicing factors, bind YCAY clusters of pre-mRNAs and assemble spliceosomes to induce the maintenance/removal of introns and exons, thus governing the development of mRNAs. Members of other splicing families operate analogously. Activity of NOVAs accounts for up to 700 alternative splicing events per cell, taking place both in the nucleus (co-transcription of mRNAs) and in the cytoplasm. Brain neurons express high levels of NOVAs, with NOVA1 predominant in cerebellum and spinal cord, NOVA2 in the cortex. Among brain physiological processes NOVAs play critical roles in axon pathfinding and spreading, structure and function of synapses, as well as the regulation of surface receptors and voltage-gated channels. In pathology, NOVAs contribute to neurodegenerative diseases and epilepsy. In vessel endothelial cells, NOVA2 is essential for angiogenesis, while in adipocytes, NOVA1 contributes to regulation of thermogenesis and obesity. In many cancers NOVA1 and also NOVA2, by interacting with specific miRNAs and by additional mechanisms, activate oncogenic roles promoting cell proliferation, colony formation, migration, and invasion. In conclusion, NOVAs regulate cell functions of physiological and pathological nature. Single cell identification and distinction, and new therapies addressed to NOVA targets might be developed in the near future.

Role of global aberrant alternative splicing events in papillary thyroid cancer prognosis

BACKGROUND

Alternative splicing events have been increasingly reported for anomalous perturbations in various cancers, including papillary thyroid cancer (PTC).

METHODS

Integration analysis of RNA sequencing and clinical information were utilized to identify survival associated splicing events in PTC. Then, several prognosis-related splicing events were submitted to develop moderate predictors for survival monitoring by using least absolute shrinkage and selection operator model. In addition, several biomedical computational algorithms were conducted to identify pathways enriched by genes with prognostic splicing events and construct regulatory network dominated by splicing factors.

RESULTS

Survival analysis in 496 PTC patients indicated that TNM stage, tumor stage, distant metastasis and tumor status were significantly correlated with PTC patients' progression-free interval. 2799 splicing events were identified as prognostic molecular events. Functional enrichment analysis suggested that prognostic splicing events are associated with several energy metabolism-related processes. Based on these prognostic events, several prognostic signatures were developed. The final prognostic signature acted as an independent prognostic factor after adjusting for several clinical parameters. Interestingly, splicing regulatory network was constructed to display potential regulatory mechanisms of splicing events in PTC.

CONCLUSIONS

Our analysis provides the status of splicing events involved in the progression and may represent an underappreciated hallmark of PTC.

Candidate lncRNA-microRNA-mRNA networks in predicting non-small cell lung cancer and related prognosis analysis

PURPOSE

The role of non-coding RNA, once thought to be dark matter, is increasingly prominent in cancer. Our article explores the effect of non-coding RNA in lung adenocarcinoma and lung squamous cell carcinoma by mining TCGA public database.

METHODS

Download the data by applying the official TCGA software. The data were analyzed by R data analysis packages, 'edgeR', 'gplots' and 'survival'. We better illustrate the potential networks of lung cancer genes by constructing ceRNAs, using Cytoscape software.

RESULTS

We obtained genes which were differentially expressed in lung adenocarcinoma and lung squamous cell carcinoma analysis. Within these differentially expressed genes, we also conducted a survival analysis to find differentially expressed genes associated with prognosis in both lung adenocarcinoma and lung squamous cell carcinoma. Based on genes differentially expressed of both lung adenocarcinoma and lung squamous cell carcinoma, we constructed a ceRNA network to illustrate the mechanism of lung adenocarcinoma and lung squamous cell carcinoma. Our study analyzed genes which were differentially expressed in lung adenocarcinoma and lung squamous cell carcinoma using the TCGA database.

CONCLUSION

Based on this, the prognosis in both lung squamous cell carcinoma and lung adenocarcinoma was analyzed. We have also constructed a ceRNA network to provide a basis for the study of ceRNA in lung adenocarcinoma and lung squamous cell carcinoma.

Identification of molecular correlations of RBM8A with autophagy in Alzheimer's disease

Our previous studies revealed RBM8A may play a role in various progressive neurological diseases. The present study aimed to explore the role of RBM8A in Alzheimer's disease (AD). RBM8A is significantly down-regulated in AD. Interestingly, 9186 differentially expressed genes are overlapped from comparisons of AD versus control and RBM8A-low versus RBM8A-high. Weight gene correlation analysis was performed and 9 functional modules were identified. Modules positively correlated with AD and RBM8A-low are significantly involved in the RAP1 signaling pathway, PI3K−AKT signaling pathway, hematopoietic cell lineage, autophagy and APELIN signaling pathway. Fifteen genes (RBM8A, RHBDF2, TNFRSF10B, ACP1, ANKRD39, CA10, CAMK4, CBLN4, LOC284214, NOVA1, PAK1, PPEF1, RGS4, TCEB1 and TMEM118) are identified as hub genes, and the hub gene-based LASSO model can accurately predict the occurrence of AD (AUC = 0.948). Moreover, the RBM8A-module-pathway network was constructed, and low expression of RBM8A down-regulates multiple module genes, including FIP200, Beclin 1, NRBF2, VPS15 and ATG12, which composes key complexes of autophagy. Thus, our study supports that low expression of RBM8A correlates with the decrease of the components of key complexes in autophagy, which could potentially contribute to pathophysiological changes of AD.

Aetiology and pathogenesis of paraneoplastic autoimmune disorders

Paraneoplastic autoimmune disorders (PAD) represent a group of autoimmune diseases associated with neoplasms. As a consequence of a remote autoimmunity-mediated effect, PAD are found in multiple organs or tissues, including the skin, blood and nervous system. Compared with non-paraneoplastic autoimmune diseases, PAD have different aetiologies, pathologies, disease symptoms and treatment responses. There are two main origins of autoimmunity in PAD: neoplasm-mediated dysregulated homeostasis in immune cells/organs and in autoantigens. Pathologically, PAD are mediated predominantly by either autoantibodies or autoreactive T-cells. In the past decade, significant progress has been achieved in increasing our understanding of the aetiology and pathology of PAD. In this review article, we aim to provide a comprehensive overview of the recent advances in this field.

The RNA binding protein neuro-oncological ventral antigen 1 (NOVA1) regulates IL-6 mRNA stability to enhance JAK2-STAT3 signaling in CRC

The molecular mechanisms governing the metastasis of colorectal cancer (CRC) are incompletely understood. In the present study, we found NOVA1 to be expressed at higher levels in CRC cell lines and tissue samples, and this upregulation was positively correlated with TNM stage (p = 0.034), poor differentiation (p = 0.001), and lymph node metastasis (p = 0.008). Both overall survival (OS) and relapse-free survival (RFS) were both significantly decreased in patients with high NOVA1 expression relative to those with low expression. Through a multivariate analysis, we determined that NOVA1 independently predicted poor outcomes in those with CRC. In further functional studies, we found that NOVA1 expression controlled the proliferation and invasive characteristics of CRC cells via a mechanism wherein NOVA1 bound and stabilized the IL6 mRNA, enhancing IL-6/JAK2/STAT3 signaling to in turn upregulate matrix metalloproteinases (MMPs) 2, 7, and 9. NOVA1 therefore plays key functional roles in regulating CRC progression, and our results further indicate that it serve as a valuable prognostic biomarker and potentially a target for therapeutic treatment in individuals with CRC.

Roles of miR-494 in Intervertebral Disk Degeneration and the Related Mechanism

OBJECTIVE

In this study, we focused on the regulatory roles of miR-494 in the pathogenesis of intervertebral disk degeneration (IDD) and the related mechanism.

METHODS

First, rat IDD models were established, and the expression levels of miR-494 in IDDs of the rats were examined. Next, human nucleus pulposus (NP) cells were cultured and transfected with miR-494 mimics and inhibitors, and the roles of miR-494 on the proliferation and apoptosis of cells were determined using MTT cell proliferation assay and flow cytometry methods. Furthermore, the targeting relationship between miR-494 and neuro-oncological ventral antigen 1 (NOVA1) was examined by dual luciferase reporter assay. Finally, the expression of NOVA1, Caspase-3, Bcl-2-associated X protein (BAX), and B-cell lymphoma-2 (BCL-2) was examined using real-time quantitative polymerase chain reaction and western blot methods.

RESULTS

The results demonstrated that the expression of miR-494 was significantly upregulated in IDD rats. Moreover, transfection of miR-494 inhibitors induced a significant increase in the proliferation and marked decrease in the apoptosis of the degenerated human NP cells. Transfection of miR-494 mimics has shown the opposite effects. Furthermore, NOVA1 has been confirmed as a target of miR-494, and the expressions of NOVA1 were significantly downregulated in IDD rats. In addition, transfection of miR-494 inhibitors significantly decreased the expression of Caspase-3 and BAX and markedly increased the expression of NOVA1 and BCL-2. Transfection of miR-494 mimics has shown the opposite effects.

CONCLUSIONS

miR-494 was upregulated in IDD, and miR-494 might regulate the proliferation and apoptosis of NP cells through targeting NOVA1.

Upregulation of the alternative splicing factor NOVA2 in colorectal cancer vasculature

Background

Tumor-specific isoforms generated by alternative splicing (AS) are demonstrated to contribute to tumor progression and can represent potential biomarkers. NOVA2 is an AS factor that in physiological conditions regulates endothelial cells' (ECs) polarity and vessel lumen maturation, likely by mediating AS of apical-basal polarity regulators. However, NOVA2 expression in tumor ECs and its regulation have never been investigated.

Methods

To elucidate this, 40 colorectal cancer patients were enrolled and NOVA2 expression was investigated by immunohistochemistry in samples bearing both the normal mucosa and the tumor tissue.

Results

NOVA2 was found expressed in ECs of tumor vasculature and, importantly, it was upregulated in tumor ECs with respect to normal mucosa ECs in all cases (P<0.001). The same samples analyzed by immunohistochemistry for the expression HIF1α, a marker of hypoxia, showed a positive and significant association with NOVA2 levels (P=0.045). Of note, NOVA2 was upregulated by hypoxia also in an in vitro ECs model.

Conclusion

Our results provide, for the first time, evidence of NOVA2 expression and upregulation in tumor ECs and highlight hypoxia as a potential regulatory factor. These findings open a completely new perspective to study tumor vasculature and to uncover NOVA2 as a potential source of biomarkers and therapeutic targets based on AS isoforms.

The expression and role of miR-181a in multiple myeloma

This study aims to investigate the role of miR-181a in multiple myeloma (MM). Fresh peripheral blood and bone marrows were collected. Expression of miR-181a, BCL-2 mRNA, and NOVA1 mRNA was detected by RT-qPCR. The correlation between miR-181a and clinical features of MM was further analyzed. miR-181a in serum and bone marrow mononuclear cells of MM patients were significantly higher. And, miR-181a level was significantly higher in MM Durie-Salmon stage III than that in stage I+II. miR-181a was positively correlated to Durie-Salmon staging, age, kidney injury, bone injury, β2-MG whereas negatively related to red blood cell, hemoglobin, and albumin. Additionally, BCL-2 and NOVA1 were predicted to be downstream targets of miR-181a. BCL-2 mRNA was significantly higher in the bone marrow mononuclear cells from MM patients. To sum up, the miR-181a expression is increased in peripheral blood and bone marrow of MM patients and is closely related to the clinical pathological indicators of MM.

NOVA1 acts as an oncogene in melanoma via regulating FOXO3a expression

Increasing studies have suggested that dysregulation of RNA‐binding proteins (RBPs) contributes to cancer progression. Neuro‐oncological ventral antigen 1 (NOVA1) is a novel RBP and plays an important role in tumour development. However, the expression and role of NOVA1 in melanoma remain unknown. In this study, we indicated that NOVA1 expression was up‐regulated in melanoma samples and cell lines. Moreover, we demonstrated that knockdown of NOVA1 suppressed melanoma cell proliferation, migration and invasion in both A375 and A875 cell lines. In addition, we showed that suppressed expression of NOVA1 enhanced forkhead box O3a (FOXO3a) expression while inhibited AKT expression in melanoma cell. Furthermore, we demonstrated that inhibited expression of FoxO3A rescued NOVA1‐mediated cell proliferation, migration and invasion in melanoma cell line A375. These results suggested that NOVA1 acted as an oncogene in the development of melanoma partly through regulating FoxO3A expression.

Neuro-oncological ventral antigen 1 (NOVA1): Implications in neurological diseases and cancers

Neuro-oncological ventral antigen 1 (NOVA1) is a RNA-binding protein that interacts with RNA containing repeats of the YCAY sequence. This protein is a brain-specific splicing factor regulating neuronal alternative splicing. It has been increasingly recognized as an important contributor to neurological disorders and carcinogenesis. In this review, we summarize the biological functions and pathological roles of NOVA1. The clinical implications of NOVA1 will also be discussed.