Project description:Melanomas are well-known for their altered mRNA expression profiles. Yet, the specific contribution of mRNA binding proteins (mRBPs) to melanoma development remains unclear. Here we identify a cluster of melanoma-enriched genes under the control of CUGBP Elav-like family member 1 (CELF1). CELF1 was discovered with a distinct prognostic value in melanoma after mining the genomic landscape of the 692 known mRBPs across different cancer types. Genome-wide transcriptomic, proteomic, and RNA-immunoprecipitation studies, together with loss-of-function analyses in cell lines, and histopathological evaluation in clinical biopsies, revealed an intricate repertoire of CELF1-RNA interactors with minimal overlap with other malignancies. This systems approach uncovered the oncogene DEK as an unexpected target and downstream effector of CELF1. Importantly, CELF1 and DEK were found to represent early-induced melanoma genes and adverse indicators of overall patient survival. These results underscore novel roles of CELF1 in melanoma, illustrating tumor type-restricted functions of RBPs in cancer.
Project description:RNA-binding proteins (RBPs) are critical regulators of gene expression, but only a small fraction have been studied for their role in malignancy. Here we report a systematic analysis of RBP CUGBP Elav-Like Family member 1 (CELF1 alias CUGBP1) roles in mRNA alternative splicing, translation and turnover in oral cancer cells. CELF1 is overexpressed in carcinogen-induced oral cancer tumorigenesis mouse model and specific inhibition of CELF1 reduces tumor growth in vivo. Deep transcriptomic analysis revealed that hundreds of mRNAs were differentially regulated as a function of CELF1 expression in oral cancer cells. More importantly, the presence of CELF1 promoted alternative splicing of several target mRNAs which are known to be involved in various cancer biological processes. Using a pulse SILAC-based quantitative proteomic approach, we observed hundreds of proteins whose translation was controlled by CELF1 and those altered proteins were implicated in malignancy. Altogether, these data provided a comprehensive view of the CELF1 mRNA regulatory network in OSCC and suggests that CELF1 is a viable target for therapeutic intervention. Significance Post-transcriptional mechanisms that regulate cancer cells which are believed to constitute the driving force of many malignancies are poorly understood. We show that oral squamous cell carcinoma (OSCC) emerge as a result of an over expressed RNA-binding protein CELF1, a protein implicated in mRNA turnover, alternative splicing and translation. The resulting mRNA expression repertoire regulates networks of genes whose expression changes regulate oral cancer pathogenesis. Inhibition of CELF1 mitigated OSCC tumor-forming capacity and offers an attractive therapeutic option for oral malignancies. Transcriptomic analysis of UMSCC-74B oral cancer cells as a function of CELF1 protein expression.
Project description:The RNA binding protein Celf1 regulates alternative splicing in the nucleus and mRNA stability and translation in the cytoplasm. Celf1 is strongly down-regulated during mouse postnatal heart development. Its re-induction in adults induced severe heart failure and reversion to fetal splicing and gene expression patterns. However, the impact of Celf1 depletion on cardiac transcriptional and posttranscriptional dynamics in neonates has not been addressed. We found that homozygous Celf1 knock-out neonates exhibited cardiac dysfunction not observed in older homozygous animals, although homozygous mice are smaller than wild type littermates throughout development. RNA-sequencing of mRNA from homozygous neonatal hearts identified a network of cell cycle genes significantly up-regulated and down-regulation of ion transport and circadian genes. Cell cycle genes are enriched for Celf1 binding sites supporting a regulatory role in mRNA stability of these transcripts. We also identified a cardiac splicing network coordinated by Celf1 depletion. Target events contain multiple Celf1 binding sites and enrichment in GU-rich motifs. Identification of direct Celf1 targets will advance our knowledge in the mechanisms behind developmental networks regulated by Celf1 and diseases where Celf1 is mis-regulated.
Project description:RNA-binding proteins (RBPs) are critical regulators of gene expression, but only a small fraction have been studied for their role in malignancy. Here we report a systematic analysis of RBP CUGBP Elav-Like Family member 1 (CELF1 alias CUGBP1) roles in mRNA alternative splicing, translation and turnover in oral cancer cells. CELF1 is overexpressed in carcinogen-induced oral cancer tumorigenesis mouse model and specific inhibition of CELF1 reduces tumor growth in vivo. Deep transcriptomic analysis revealed that hundreds of mRNAs were differentially regulated as a function of CELF1 expression in oral cancer cells. More importantly, the presence of CELF1 promoted alternative splicing of several target mRNAs which are known to be involved in various cancer biological processes. Using a pulse SILAC-based quantitative proteomic approach, we observed hundreds of proteins whose translation was controlled by CELF1 and those altered proteins were implicated in malignancy. Altogether, these data provided a comprehensive view of the CELF1 mRNA regulatory network in OSCC and suggests that CELF1 is a viable target for therapeutic intervention. Significance Post-transcriptional mechanisms that regulate cancer cells which are believed to constitute the driving force of many malignancies are poorly understood. We show that oral squamous cell carcinoma (OSCC) emerge as a result of an over expressed RNA-binding protein CELF1, a protein implicated in mRNA turnover, alternative splicing and translation. The resulting mRNA expression repertoire regulates networks of genes whose expression changes regulate oral cancer pathogenesis. Inhibition of CELF1 mitigated OSCC tumor-forming capacity and offers an attractive therapeutic option for oral malignancies.
Project description:RNA-binding proteins (RBPs) are important regulators of gene expression, but few have been studied for their role in malignancy. Using proteo-genomic techniques, we have identified the RBP CELF1 mRNA alternative splicing, translation and turnover targets in oral cancer cells. SILAC and Mass spectrometry analysis, identified 1322 proteins translationally controlled by CELF1 and many of these altered proteins were implicated in malignancy. Our genomic and proteomic analyses provided a comprehensive view of the CELF1 mRNA regulatory network in oral cancer and suggests that CELF1 is a viable target for therapeutic intervention.
Project description:The CUG-BP and ETR-3-like factor 1 (Celf1) RNA binding protein plays an important role in heart and muscle development, and is over-expressed in the disease myotonic dystrophy. Celf1 has known roles in regulation of RNA splicing, RNA stability, and protein translation. To identify transcriptome-wide targets of the Celf1 protein, we performed CLIP-seq against Celf1 using the 3B1 antibody, in myoblasts, heart tissue, and muscle tissue. RNA Bind-N-Seq was performed using recombinant CELF1 protein in the presence of competing amounts of recombinant MBNL1 protein.
Project description:The CUG-BP and ETR-3-like factor 1 (Celf1) RNA binding protein plays an important role in heart and muscle development, and is over-expressed in the disease myotonic dystrophy. Celf1 has known roles in regulation of RNA splicing, RNA stability, and protein translation. To identify transcriptome-wide targets of the Celf1 protein in heart, we performed RNA-Seq of polyA+ RNA from mice inducibly expressing Celf1 in the heart. Mice were engineered to express the reverse tetracycline trans-activator (rtTA) from a heart-specific alpha myosin heavy chain promoter, and an N-terminal Flag-tagged version of the LYLQ isoform of human Celf1 from a tet-inducible promoter. Mice were fed doxycycline to induce Celf1 expression in heart, and hearts were harvested from 3 mice each at 12 hour, 24 hour, 72 hour, and 7 day time points. To account for potential doxycycline-dependent effects, control mice were fed doxycycline for 72 hours but these mice did not contain the tet-inducible Celf1 cassette. In total, 15 hearts were analyzed by RNA-Seq.
Project description:The CUG-BP and ETR-3-like factor 1 (Celf1) RNA binding protein plays an important role in heart and muscle development, and is over-expressed in the disease myotonic dystrophy. Celf1 has known roles in regulation of RNA splicing, RNA stability, and protein translation. To identify transcriptome-wide targets of the Celf1 protein, we performed CLIP-seq against Celf1 using the 3B1 antibody, in myoblasts, heart tissue, and muscle tissue.
Project description:The CUG-BP and ETR-3-like factor 1 (Celf1) RNA binding protein plays an important role in heart and muscle development, and is over-expressed in the disease myotonic dystrophy. Celf1 has known roles in regulation of RNA splicing, RNA stability, and protein translation. To identify transcriptome-wide targets of the Celf1 protein in heart, we performed RNA-Seq of polyA+ RNA from mice inducibly expressing Celf1 in the muscle.