The role of CELF family in neurodevelopment and neurodevelopmental disorders.

RNA-binding proteins (RBPs) bind to RNAs and are crucial for regulating RNA splicing, stability, translation, and transport. Among these proteins, the CUGBP Elav-like family (CELF) is a highly conserved group crucial for posttranscriptional regulation by binding to CUG repeats. Comprising CELF1-6, this family exhibits diverse expression patterns and functions. Dysregulation of CELF has been implicated in various neural disorders, encompassing both neurodegenerative and neurodevelopmental conditions, such as Alzheimer's disease and autism. This article aims to provide a comprehensive summary of the CELF family's role in neurodevelopment and neurodevelopmental disorders. Understanding CELF's mechanisms may offer clues for potential therapeutic strategies by regulating their targets in neurodevelopmental disorders.

miR-208a-3p regulated by circUQCRC2 suppresses ischemia/reperfusion-induced acute kidney injury by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis.

ABSTRACT: Background : Acute kidney injury (AKI) is a prevalent clinical syndrome with persistent kidney dysfunction. Renal ischemia/reperfusion (I/R) injury is a major cause of AKI. miR-208a-3p overexpression attenuated myocardial I/R injury. This study aims to investigate the role and mechanism of miR-208a-3p in I/R-induced AKI. Methods : AKI models were established using hypoxia/reoxygenation (H/R)-exposed tubule epithelial cell HK-2 and I/R-induced mice. The function and mechanism of miR-208a-3p were investigated by gain- or loss-of-function methods using real-time PCR, CCK-8, flow cytometry, ELISA, western blot, hematoxylin-eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, detection of Fe 2+ , reactive oxygen species, blood urea nitrogen and creatinine, and luciferase reporter assay. Results : miR-208a-3p expression was suppressed, while the expression of CELF2 and circular RNA ubiquinol-cytochrome c reductase core protein 2 (circUQCRC2) was increased in both AKI models. miR-208a-3p upregulation or circUQCRC2 silencing increased the viability, decreased the levels of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6), reduced apoptosis and contents of Fe 2+ and reactive oxygen species, elevated expression of GPX4 and SLC7A11, and reduced ACSL4 expression in H/R-stimulated HK-2 cells. In addition, miR-208a-3p improved kidney function by alleviating renal injury, apoptosis, inflammation, and ferroptosis in AKI mouse model. CELF2 was a target gene of miR-208a-3p, which was negatively modulated by circUQCRC2. Overexpression of CELF2 blocked the function of miR-208a-3p upregulation or circUQCRC2 silencing on H/R-treated HK-2 cells. Moreover, the effects of circUQCRC2 downregulation on H/R-injured cells were also reversed by miR-208a-3p inhibitor. Conclusions : miR-208a-3p regulated by circUQCRC2 could attenuate I/R-induced AKI by inhibiting CELF2-mediated tubular epithelial cell apoptosis, inflammation and ferroptosis. This study provides potential therapeutic targets for I/R-induced AKI.

Loss of RNA-binding protein CELF2 promotes acute leukemia development via FAT10-mTORC1.

RNA-binding proteins (RBPs) are critical regulators for RNA transcription and translation. As a key member of RBPs, ELAV-like family protein 2 (CELF2) has been shown to regulate RNA splicing and embryonic hematopoietic development and was frequently seen dysregulated in acute myeloid leukemia (AML). However, the functional role(s) of CELF2 in hematopoiesis and leukemogenesis has not been fully elucidated. In the current study, we showed that Celf2 deficiency in hematopoietic system led to enhanced HSCs self-renewal and differentiation toward myeloid cells in mice. Loss of Celf2 accelerated myeloid cell transformation and AML development in MLL-AF9-induced AML murine models. Gene expression profiling integrated with RNA immunoprecipitation sequencing (RIP-Seq), together with biochemical experiments revealed that CELF2 deficiency stabilizes FAT10 mRNA, promotes FAT10 translation, thereby increases AKT phosphorylation and mTORC1 signaling pathway activation. Notably, combination therapy with a mTORC1 inhibitor (Rapamycin) and a MA9/DOTL1 inhibitor (EPZ-5676) reduced the leukemia burden in MLL-AF9 mice lacking Celf2 in vivo. Our study elucidated a novel mechanism by which the CELF2/FAT10-AKT/mTORC1 axis regulates the proliferation of normal blood cells and the development of AML, thus providing potential therapeutic targets for myeloid leukemia suppression.

Generation and characterization of a human iPSC line and gene-corrected isogenic line derived from a patient with a CELF2 gene mutation.

The identification of neurodevelopmental defects in a patient harboring a heterozygous de novo missense variant (NM_006561.4, c.1517G > A, p.Arg506His) within the CELF2 gene. Here, we describe the establishment of a patient-derived induced pluripotent stem cell (iPSC) line, alongside an isogenic gene-corrected iPSC line, achieved through CRISPR/Cas9 genome editing. These lines exhibit the expression of pluripotency markers, demonstrate differentiation potential into all three germ layers, and maintain a normal karyotype. These iPSC lines serve as valuable tools for investigating the consequences of CELF2 related neurodevelopmental disorders.

Celf4 controls mRNA translation underlying synaptic development in the prenatal mammalian neocortex.

Abnormalities in neocortical and synaptic development are linked to neurodevelopmental disorders. However, the molecular and cellular mechanisms governing initial synapse formation in the prenatal neocortex remain poorly understood. Using polysome profiling coupled with snRNAseq on human cortical samples at various fetal phases, we identify human mRNAs, including those encoding synaptic proteins, with finely controlled translation in distinct cell populations of developing frontal neocortices. Examination of murine and human neocortex reveals that the RNA binding protein and translational regulator, CELF4, is expressed in compartments enriched in initial synaptogenesis: the marginal zone and the subplate. We also find that Celf4/CELF4-target mRNAs are encoded by risk genes for adverse neurodevelopmental outcomes translating into synaptic proteins. Surprisingly, deleting Celf4 in the forebrain disrupts the balance of subplate synapses in a sex-specific fashion. This highlights the significance of RNA binding proteins and mRNA translation in evolutionarily advanced synaptic development, potentially contributing to sex differences.

Long noncoding RNA LINC01594 inhibits the CELF6-mediated splicing of oncogenic CD44 variants to promote colorectal cancer metastasis.

Long noncoding RNAs (lncRNAs) play critical roles in tumorigenesis and tumor metastasis. However, the underlying mechanisms of lncRNAs in colorectal cancer (CRC) need further exploration. By using data from The Cancer Genome Atlas (TCGA) and GEO databases, we identified a novel CRC-related lncRNA, LINC01594, that is significantly upregulated in CRC and associated with poor prognosis. In vitro and in vivo, gain- and loss-of-function experiments demonstrated that LINC01594 promotes metastasis in CRC. LINC01594 functions as a DNMT1 scaffold, increasing the level of CELF6 promoter methylation. LINC01594 also competitively binds the transcription factor p53, decreasing CELF6 expression. This inhibited the exon skipping of CD44 V4-V7 induced by CELF6. In summary, this study highlights a novel CRC biomarker and therapeutic target, LINC01594, and the findings suggest that the LINC01594-CELF6-CD44 axis might serve as a biomarker and therapeutic target in CRC.

Hypoxia-induced lncRNA MRVI1-AS1 accelerates hepatocellular carcinoma progression by recruiting RNA-binding protein CELF2 to stabilize SKA1 mRNA.

BACKGROUND: Long non-coding RNAs (lncRNAs) perform a vital role during the progression of hepatocellular carcinoma (HCC). Here, we aimed to identify a novel lncRNA involved in HCC development and elucidate the underlying molecular mechanism. METHODS: The RT-qPCR and TCGA dataset analysis were applied to explore the expressions of MRVI1-AS1 in HCC tissues and cell lines. Statistical analysis was applied to analyze the clinical significance of MRVI1-AS1 in HCC. The functions of MRVI1-AS1 in HCC cells metastasis and growth were explored by transwell assays, wound healing assay, MTT assay, EdU assay, the intravenous transplantation tumor model, and the subcutaneous xenograft tumor model. Microarray mRNA expression analysis, dual luciferase assays, and actinomycin D treatment were used to explore the downstream target of MRVI1-AS1 in HCC cells. RIP assay was applied to assess the direct interactions between CELF2 and MRVI1-AS1 or SKA1 mRNA. Rescue experiments were employed to validate the functional effects of MRVI1-AS1, CELF2, and SKA1 on HCC cells. RESULTS: MRVI1-AS1 was found to be dramatically upregulated in HCC and the expression was strongly linked to tumor size, venous infiltration, TNM stage, as well as HCC patients' outcome. Cytological experiments and animal experiments showed that MRVI1-AS1 promoted HCC cells metastasis and growth. Furthermore, SKA1 was identified as the downstream targeted mRNA of MRVI1-AS1 in HCC cells, and MRVI1-AS1 increased SKA1 expression by recruiting CELF2 protein to stabilize SKA1 mRNA. In addition, we found that MRVI1-AS1 expression was stimulated by hypoxia through a HIF-1-dependent manner, which meant that MRVI1-AS was a direct downstream target gene of HIF-1 in HCC. CONCLUSION: In a word, our findings elucidated that hypoxia-induced MRVI1-AS1 promotes metastasis and growth of HCC cells via recruiting CELF2 protein to stabilize SKA1 mRNA, pointing to MRVI1-AS1 as a promising clinical application target for HCC therapy.

MIMT1 and LINC01550 are uncharted lncRNAs down-regulated in colorectal cancer.

Incomplete knowledge of the molecular basis of colorectal cancer, with subsequent limitations in early diagnosis and effective treatment, has contributed to this form of malignancy becoming the second most common cause of cancer-related death worldwide. With the advances in high-throughput profiling techniques and the availability of public data sets such as The Cancer Genome Atlas Program (TCGA), a broad range of coding transcripts have been profiled and their underlying modes of action have been mapped. However, there is still a huge gap in our understanding of noncoding RNA dysregulation. To this end, we used a bioinformatics approach to shortlist and evaluate yet-to be-profiled long noncoding RNAs (lncRNAs) in colorectal cancer. We analysed the TCGA RNA-seq data and followed this by validating the expression patterns using a qPCR technique. Analysing in-house clinical samples, the real-time PCR method revealed that the shortlisted lncRNAs, that is MER1 Repeat Containing Imprinted Transcript 1 (MIMT1) and Non-Protein Coding RNA 1550 (LINC01550), were down-regulated in colorectal cancer tumours compared with the paired adjacent normal tissues. Mechanistically, the in silico results suggest that LINC01550 could form a complex competitive endogenous RNA (ceRNA) network leading to the subsequent regulation of colorectal cancer-related genes, such as CUGBP Elav-Like Family Member (CELF2), Polypyrimidine Tract Binding Protein 1 (PTBP1) and ELAV Like RNA Binding Protein 1 (ELAV1). The findings of this work indicate that MIMT1 and LINC01550 could be novel tumour suppressor genes that can be studied further to assess their roles in regulating the cancer signalling pathway(s).

Role of SNPs located in the exon 9 of ATAPA1 gene on goose egg production.

The meat and egg of goose is one of the main components of human food supply. The improvement of goose egg production is particularly important for the increasing human population. However, limited information is available about the effective molecular markers and mechanisms of egg production in goose. In this study, we jointly utilized the data of genome resequencing in different egg production Sichuan white goose and transcriptome at different follicle development stages to identified the molecular markers and mechanisms of egg production. The coefficient of variation of individual egg production in Sichuan white goose population is 0.42 to 0.49. Fifty individuals with the highest (laying 365 days egg number, LEN365 = 79-145) and 50 individuals with the lowest (LEN365 = 8-48) egg production were divided into high and low egg production groups. Based on whole-genome sequencing data of the selected samples, 36 SNPs (annotation novel.12.470, CELF2, ATP1A1, KCNJ6, RAB4A, UST, REV3L, DHX15, CAVN2, SLC5A9, Cldn5, MRPS23, and Tspan2) associated with the LEN365 were identified, involving multiple pathways such as metabolism and endocrinology. Notably, 5 SNPs located in the exon9 of ATP1A1 were identified by GWAS analysis. The association analysis with LEN365 showed the phenotypic variance explained of this haplotype consisting of 5 SNPs is 20.51%. Through transcriptome data analysis, we found the expression of ATP1A1 in the granular layers was increased in the stage of small yellow follicle to large yellow follicle (LYF) and LYF to F5, while decreased in F2 to F1. For the first time, we report the haplotype region formed by 5 SNPS on exon9 of ATP1A1 is associated with egg production in goose and involved in follicle selection and maturation processes.

ELK1-Induced upregulation of long non-coding TNK2-AS1 promotes the progression of acute myeloid leukemia by EZH2-mediated epigenetic silencing of CELF2.

Acute myeloid leukemia (AML) is the second most common hematological malignancy after lymphoma in the world. Long non-coding RNAs (LncRNAs) have been suggested as key regulators of cancer development and progression in AML. As a member of lncRNA family, the biological role and mechanisms of tyrosine kinase non receptor 2 antisense RNA 1 (TNK2-AS1) in AML is still unclear. The expression of TNK2-AS1 was measured with RT-qPCR in AML cell lines. The changes of the proliferation, apoptosis, and differentiation in TNK2-AS1 shRNA-transfected HL-60 and THP-1 cells were detected with CCK-8, EdU, flow cytometry, Western blot, and NBT assays. Molecular control of TNK2-AS1 on CUGBP Elav-like family member 2 (CELF2) and ETS domain-containing protein-1 (ELK1) on TNK2-AS1 was assessed by chromatin immunoprecipitation (ChIP), RT-qPCR, Western blot, and RNA immunoprecipitation (RIP) assays. TNK2-AS1 expression was upregulated in AML cell lines and negatively correlated with survival patients. Knockdown of TNK2-AS1 markedly reduced AML cell proliferation and promoted apoptosis and differentiation. Likewise, TNK2-AS1 knockdown significantly suppressed tumor growth in vivo. Mechanistically, the upregulation of TNK2-AS1 was activated by transcription factor ELK1. We also uncovered that TNK2-AS1 exerted tumor-promoting effect through silencing CELF2 via binding with EZH2, thus activating PI3K/Akt pathway in AML cells. Elevated expression of TNK2-AS1 was induced by ELK1 and facilitated AML progression by suppressing CELF2 expression via EZH2-mediated epigenetic silencing, suggesting TNK2-AS1 may be a promising therapeutic target and prognostic marker for AML patients.

Exosomal miR-625-3p secreted by cancer-associated fibroblasts in colorectal cancer promotes EMT and chemotherapeutic resistance by blocking the CELF2/WWOX pathway.

Migration, invasion, epithelial-mesenchymal transformation (EMT), and chemotherapeutic resistance are the leading causes of therapeutic failure in people with colorectal cancer (CRC). The migration of exosomal miRNA between cancer cells and the tumor microenvironment is directly associated with malignant behavior in cancer-associated fibroblasts (CAFs). In the context of earlier research, the purpose of the current study was to assess the role and potential mechanism of miR-625-3p released by CAFs in CRC cells. Exosomes were extracted and purified from CAFs conditioned medium by ultracentrifugation. Western blot, immunohistochemistry, CCK-8, transwell assay, H&E staining, Tunnel, real-time PCR, double luciferase assay, RNA-binding protein immunoprecipitation (RIP), and immunofluorescence double staining experiments were used to investigate the effects of CAFs-Exo and miR-625-3p on CRC cell invasion, migration, proliferation, EMT, chemotherapeutic resistance, and molecular mechanisms. The current results indicated that CAFs-Exo was directly internalized by CRC cells, and exosomal miR-625-3p derived from CAFs might promote migration, invasion, EMT and chemotherapeutic resistance in CRC cells by inhibiting the CELF2/WWOX pathway, providing a potential candidate for CRC prediction and treatment.

Natural Antisense Long Noncoding RNA HHIP-AS1 Suppresses Non-Small-Cell Lung Cancer Progression by Increasing HHIP Stability via Interaction with CELF2.

Non-small-cell lung cancer (NSCLC) is a major category of lung cancer, with high incidence and high mortality. Natural antisense long noncoding RNAs (lncRNAs) are involved in the development of NSCLC via their regulation of biological processes. However, the function of the lncRNA Hedgehog-interacting protein antisense RNA 1 (HHIP-AS1) in NSCLC is mostly unknown. In the study discussed here, HHIP-AS1 and HHIP levels were predicted based on the TCGA database, and detected via qRT-PCR or western blotting assays. Cell proliferation, migration, and invasion were measured via CCK-8 and trans-well assays. Related protein levels were measured using western blotting analysis. The results showed that HHIP-AS1 and HHIP levels are downregulated in NSCLC, and that low HHIP-AS1 and HHIP expression is associated with poor outcomes. HHIP-AS1 overexpression represses cell proliferation, migration, and invasion in NSCLC. HHIP-AS1 enhances HHIP expression and stability, and this effect is mediated by CELF2. HHIP silencing attenuates the suppressive roles of HHIP-AS1 in proliferation, migration, and invasion. As a result of these findings, it is concluded that HHIP-AS1 overexpression restrains proliferation, migration, and invasion of NSCLC cells by increasing HHIP stability via its targeting of CELF2.

Construction of MicroRNA-Target Interaction Networks Based on MicroRNA Expression Profiles of HRV16-infected H1-HeLa Cells.

In the present study we investigated the changes in miRNA levels inhuman rhinovirus 16 (HRV16)-infected cells. A small RNA deep sequencing experiment was performed through next-generation sequencing. In total, 53 differentially expressed miRNAs were confirmed by RT-qPCR, including 37 known miRNAs and 16 novel miRNAs. Interaction networks between differentially expressed miRNAs and their targets were established by mirDIP and Navigator. The prediction results showed that QKI, NFAT5, BNC2, CELF2, LCOR, MBNL2, MTMR3, NFIB, PPARGC1A, RSBN1, TRPS1, WDR26, and ZNF148, which are associated with cellular differentiation and transcriptional regulation, were recognized by 12, 11, or 9 miRNAs. Many correlations were observed between transcriptional or post-transcriptional regulation of an miRNA and the expression levels of its target genes in HRV16-infected H1-HeLa cells.

MECP2-related pathways are dysregulated in a cortical organoid model of myotonic dystrophy.

Myotonic dystrophy type 1 (DM1) is a multisystem, autosomal-dominant inherited disorder caused by CTG microsatellite repeat expansions (MREs) in the 3' untranslated region of the dystrophia myotonica-protein kinase (DMPK) gene. Despite its prominence as the most common adult-onset muscular dystrophy, patients with congenital to juvenile-onset forms of DM1 can present with debilitating neurocognitive symptoms along the autism spectrum, characteristic of possible in utero cortical defects. However, the molecular mechanism by which CTG MREs lead to these developmental central nervous system (CNS) manifestations is unknown. Here, we showed that CUG foci found early in the maturation of three-dimensional (3D) cortical organoids from DM1 patient-derived induced pluripotent stem cells (iPSCs) cause hyperphosphorylation of CUGBP Elav-like family member 2 (CELF2) protein. Integrative single-cell RNA sequencing and enhanced cross-linking and immunoprecipitation (eCLIP) analysis revealed that reduced CELF2 protein-RNA substrate interactions results in misregulation of genes critical for excitatory synaptic signaling in glutamatergic neurons, including key components of the methyl-CpG binding protein 2 (MECP2) pathway. Comparisons to MECP2(y/-) cortical organoids revealed convergent molecular and cellular defects such as glutamate toxicity and neuronal loss. Our findings provide evidence suggesting that early-onset DM1 might involve neurodevelopmental disorder-associated pathways and identify N-methyl-d-aspartic acid (NMDA) antagonists as potential treatment avenues for neuronal defects in DM1.

CELF4 regulates spine formation and depression-like behaviors of mice.

Chronic social stress is closed related to major depressive disorder, torturing millions of people and may destroy their lives. The prefrontal cortex is one of the core brain areas involved in pathological development and behavior changes in depression. CELF4 is a neuronal RNA-binding protein and plays an essential role in RNA processing. It is closely related to some neurological disorders, including seizures and neuroticism. Most recently, GWAS analysis indicates it is one of the significant genes associated with depression. Nonetheless, we are still unknown whether and how CELF4 gets involved in depression. Here, we reported that the protein and mRNA expression levels of CELF4 in the PFC were decreased in the CSDS depression model, as well as the spine number. Furthermore, we disturbed CELF4 expression in the PFC by using the AAV-shCELF4 virus. Unexpectedly, the spine number showed a decrease in PFC because of the impaired CELF4 expression, and the AAV-shCELF4 mice displayed depression-like behaviors. Our results suggest that CELF4 is critical for spine number and acts a critical role in depression-like behaviors of mice.

The natural compound neobractatin inhibits cell proliferation mainly by regulating the RNA binding protein CELF6.

The fruits of Garcinia bracteata can be eaten raw or processed into spices, which are considered to possess nutritional and medicinal value. Neobractatin (NBT) is a natural compound isolated from Garcinia bracteate. This study showed that NBT showed antitumor effect by upregulation of CELF6. CELF6, an RNA-binding protein of the CELF family, is involved in cancer cell proliferation. However, the role of CELF6 in human cervical cancer remains unknown. Here, we showed that CELF6 overexpression significantly suppressed HeLa cell proliferation. Mechanistically, the RNA immunoprecipitation sequencing (RIP-seq) results suggested that CELF6 physically targeted the cyclin D1 transcript, affecting protein stability. Overexpression of CELF6 increased the degradation of cyclin D1. Consistent results were obtained for the effect of NBT, which increased the expression of CELF6 at both the mRNA and protein levels. An in vivo study further confirmed the regulatory effect of NBT on CELF6 and cyclin D1 levels in a HeLa xenograft model. Similar effects of NBT on CELF6 were also shown in K562 cells in vitro and in vivo. In conclusion, our findings identified CELF6 as a tumor suppressor and a novel therapeutic target in cervical cancer. The upregulation of CELF6 expression by NBT and its antiproliferative effect on HeLa cells indicated that NBT from G. bracteata might be a small-molecule compound targeting CELF6.

CELF Family Proteins in Cancer: Highlights on the RNA-Binding Protein/Noncoding RNA Regulatory Axis.

Post-transcriptional modifications to coding and non-coding RNAs are unquestionably a pivotal way in which human mRNA and protein diversity can influence the different phases of a transcript's life cycle. CELF (CUGBP Elav-like family) proteins are RBPs (RNA-binding proteins) with pleiotropic capabilities in RNA processing. Their responsibilities extend from alternative splicing and transcript editing in the nucleus to mRNA stability, and translation into the cytoplasm. In this way, CELF family members have been connected to global alterations in cancer proliferation and invasion, leading to their identification as potential tumor suppressors or even oncogenes. Notably, genetic variants, alternative splicing, phosphorylation, acetylation, subcellular distribution, competition with other RBPs, and ultimately lncRNAs, miRNAs, and circRNAs all impact CELF regulation. Discoveries have emerged about the control of CELF functions, particularly via noncoding RNAs, and CELF proteins have been identified as competing, antagonizing, and regulating agents of noncoding RNA biogenesis. On the other hand, CELFs are an intriguing example through which to broaden our understanding of the RBP/noncoding RNA regulatory axis. Balancing these complex pathways in cancer is undeniably pivotal and deserves further research. This review outlines some mechanisms of CELF protein regulation and their functional consequences in cancer physiology.

CircPTK2 inhibits the tumorigenesis and metastasis of gastric cancer by sponging miR-134-5p and activating CELF2/PTEN signaling.

BACKGROUND: CircRNAs are a new subset of noncoding RNAs formed by covalent closed loops and play crucial roles in the regulation of cancer gene expression. However, the roles and underlying mechanisms of circRNAs in gastric cancer (GC) remain indistinct. This study aimed to explore the role and mechanism of hsa_circ_0006421 (circPTK2) in GC. METHODS: The differential expression of circRNAs between GC tissues and adjacent normal tissues were identified by a circRNA expression profiling. Associations of circPTK2 or miR-134-5p expression with clinicopathological characteristics and prognosis of GC patients were analyzed by chi-square of Fisher's exact tests and Kaplan-Meier analysis. CCK8, colony formation, EdU assays and animal models were performed to assess the effects of circPTK2 on proliferation and invasion of GC cells. CircPTK2-specific probes were used to purify the RNA pulled down from the circPTK2, and enrichment of circPTK2 and miR-134-5p was detected by qRT-PCR. The effects of circPTK2 on miR-134-5p expression and CELF2/PTEN signaling were examined by qRT-PCR and Western blotting analysis. RESULTS: Low expression of circPTK2 and high expression of miR-134-5p were related to the poor survival, and high expression of miR-134-5p was related to the tumor recurrence in GC patients. Overexpressing circPTK2 suppressed the proliferation, colony formation, DNA synthesis and cell invasion as well as xenograft tumor growth and lung metastasis in vitro and in vivo, whereas silencing circPTK2 had the opposite effects. Moreover, circPTK2 was negatively correlated and co-localized with miR-134-5p in the cytoplasm of GC tissue cells. circPTK2 bound to and sponged miR-134-5p in GC cells, and miR-134-5p facilitated cell growth and invasion but attenuated circPTK2 induced tumor suppressive effects and CELF2/PTEN signaling activation in GC cells. CONCLUSIONS: circPTK2 functions as a tumor suppressor in GC by sponging miR-134-5p and activating the CELF2/PTEN axis.

CELF2 is a candidate prognostic and immunotherapy biomarker in triple-negative breast cancer and lung squamous cell carcinoma: A pan-cancer analysis.

CUGBP Elav-like family member 2(CELF2) plays crucial roles in the development and activation of T cell. However, the impacts of CELF2 on tumour-infiltrating immune cells (TIICs) and clinical outcomes of tumours remain unclear. In this study, we found that elevated CELF2 expression was markedly correlated with prolonged survival in multiple tumours, particularly in breast and lung cancers. Notably, CELF2 only impacted the prognosis of triple-negative breast cancer (TNBC) with lymph node metastasis. Further investigation showed CELF2 expression was positively correlated with the infiltration abundance of dendritic cells (DCs), CD8+ T cells and neutrophils in breast invasive carcinoma (BRCA) and DCs in lung squamous cell carcinoma (LUSC). CELF2 also had strong correlations with markers of diverse TIICs such as T cells, tumour-associated macrophages and DCs in BRCA and LUSC. Importantly, CELF2 was significantly associated with plenty of immune checkpoint molecules (ICMs) and outperformed five prevalent biomarkers including PD-1, PD-L1, CTLA-4, CD8 and tumour mutation burden in predicting immunotherapeutic responses. Immunohistochemistry also revealed lower protein levels of CELF2 in TNBC and LUSC compared to normal tissues, and patients with high expression showed significantly prolonged prognosis. In conclusion, we demonstrated that increased CELF2 expression was closely related to better prognosis and superior TIIC infiltration and ICM expression, particularly in BRCA and LUSC. CELF2 also performed well in evaluating the immunotherapeutic efficacy, suggesting CELF2 might be a promising biomarker.

Nucleocytoplasmic transport of the RNA-binding protein CELF2 regulates neural stem cell fates.

The development of the cerebral cortex requires balanced expansion and differentiation of neural stem/progenitor cells (NPCs), which rely on precise regulation of gene expression. Because NPCs often exhibit transcriptional priming of cell-fate-determination genes, the ultimate output of these genes for fate decisions must be carefully controlled in a timely fashion at the post-transcriptional level, but how that is achieved is poorly understood. Here, we report that de novo missense variants in an RNA-binding protein CELF2 cause human cortical malformations and perturb NPC fate decisions in mice by disrupting CELF2 nucleocytoplasmic transport. In self-renewing NPCs, CELF2 resides in the cytoplasm, where it represses mRNAs encoding cell fate regulators and neurodevelopmental disorder-related factors. The translocation of CELF2 into the nucleus releases mRNA for translation and thereby triggers NPC differentiation. Our results reveal that CELF2 translocation between subcellular compartments orchestrates mRNA at the translational level to instruct cell fates in cortical development.