Project description:MicroRNAs (miRNAs or miRs) are small, noncoding RNAs that are implicated in the regulation of nearly all biological processes. Global miRNA biogenesis is altered in many cancers and RNA-binding proteins (RBPs) have been shown to play a role in this process, presenting a promising avenue for targeting miRNA dysregulation in disease. miR-34a exhibits tumor-suppressive functions by targeting cell cycle regulators CDK4/6 and anti-apoptotic factor Bcl-2, among other regulatory pathways such as Wnt, TGF-, and Notch signaling. Many cancers show downregulation or loss of miR-34a, and synthetic miR-34a supplementation has been shown to inhibit tumor growth in vivo; however, the post-transcriptional mechanisms by which miR-34a is lost in cancer are not entirely understood. Here, we have used a proteomics-mediated approach to identify Squamous cell carcinoma antigen recognized by T-cells 3 (SART3) as a putative pre-miR-34a-binding protein. SART3 is a spliceosome recycling factor and nuclear RBP with no previously reported role in miRNA regulation. We demonstrate that SART3 binds pre-miR-34a with specificity over pre-let-7d and begin to elucidate a new functional role for this protein in non-small lung cancer cells. Overexpression of SART3 led to increased miR-34a levels, downregulation of the miR-34a target genes CDK4 and CDK6, and cell cycle arrest in the G1 phase. In vitro binding studies showed that the RNA-recognition motifs within the SART3 sequence are responsible for selective pre-miR-34a binding. Collectively, our results present evidence for an influential role of SART3 in miR-34a biogenesis and cell cycle progression.
Project description:The Zeb1 transcriptional repressor plays a key role in metastasis through the down-regulation of genes that are strong inducers of epithelial differentiation and inhibitors of stem-ness. Here we report that Zeb1 controls the expression of numerous oncogenic and tumor suppressive microRNAs (miRs). Zeb1 stimulated pro-migratory cytoskeletal processes by down-regulating miR-34a and activated Rho GTPases through Arhgap1, a Cdc42 GTPase activating protein and novel miR-34a target gene. Poor-prognosis human lung adenocarcinomas were highly enriched in a cytoskeletal gene signature activated by miR-34a down-regulation. These findings suggest that Zeb1 regulates a miR network and drives pro-migratory cytoskeletal processes through miR-34a.
Project description:The Zeb1 transcriptional repressor plays a key role in metastasis through the down-regulation of genes that are strong inducers of epithelial differentiation and inhibitors of stem-ness. Here we report that Zeb1 controls the expression of numerous oncogenic and tumor suppressive microRNAs (miRs). Zeb1 stimulated pro-migratory cytoskeletal processes by down-regulating miR-34a and activated Rho GTPases through Arhgap1, a Cdc42 GTPase activating protein and novel miR-34a target gene. Poor-prognosis human lung adenocarcinomas were highly enriched in a cytoskeletal gene signature activated by miR-34a down-regulation. These findings suggest that Zeb1 regulates a miR network and drives pro-migratory cytoskeletal processes through miR-34a.
Project description:The Zeb1 transcriptional repressor plays a key role in metastasis through the down-regulation of genes that are strong inducers of epithelial differentiation and inhibitors of stem-ness. Here we report that Zeb1 controls the expression of numerous oncogenic and tumor suppressive microRNAs (miRs). Zeb1 stimulated pro-migratory cytoskeletal processes by down-regulating miR-34a and activated Rho GTPases through Arhgap1, a Cdc42 GTPase activating protein and novel miR-34a target gene. Poor-prognosis human lung adenocarcinomas were highly enriched in a cytoskeletal gene signature activated by miR-34a down-regulation. These findings suggest that Zeb1 regulates a miR network and drives pro-migratory cytoskeletal processes through miR-34a. Total RNA was extracted from primary tumors from mice injected with 344SQ-vector and -miR-34a cells, and then hybridized to Affymetrix GeneChip Mouse Genome 430 2.0 array. Determination of differentially expressed genes was carried out.
Project description:The Zeb1 transcriptional repressor plays a key role in metastasis through the down-regulation of genes that are strong inducers of epithelial differentiation and inhibitors of stem-ness. Here we report that Zeb1 controls the expression of numerous oncogenic and tumor suppressive microRNAs (miRs). Zeb1 stimulated pro-migratory cytoskeletal processes by down-regulating miR-34a and activated Rho GTPases through Arhgap1, a Cdc42 GTPase activating protein and novel miR-34a target gene. Poor-prognosis human lung adenocarcinomas were highly enriched in a cytoskeletal gene signature activated by miR-34a down-regulation. These findings suggest that Zeb1 regulates a miR network and drives pro-migratory cytoskeletal processes through miR-34a. Microarray-based interrogation of global miR expression changes in a non-metastatic KP cell line (393P) that undergoes EMT and gains invasive and metastatic capabilities following forced Zeb1 expression (393P_Zeb1). two group comparison
Project description:The LC-MS/MS raw data (.mzxml) of nasal polyps and sinonasal squamous cell carcinoma patients.The study utilized 90 datasets from 30 individual nasal tissue samples across three independent experiments (Nasal polyps (NP): 48 datasets, SNSCC: 42 datasets).
Project description:Previous studies have evaluated the role of miRNAs in the initiation and progression of cancer. MiR-34a was found to be downregulated in several tumors, including medulloblastoma. We here analysed the function of miR-34a in vivo by targeted transgenesis to generate mice with constitutive deletion of the miR-34a gene, which resulted in the absence of mir-34a in all analysed tissues. Nevertheless, these mice were viable and fertile. A comprehensive standardized phenotypic analysis including more than 300 single parameters performed by the German Mouse Clinic revealed no apparent phenotype. Analysis of miR-34a expression in human medulloblastomas and medulloblastoma cell lines revealed significant downregulation as compared to human cerebellum. Re-expression of mir-34a in human medulloblastoma cells in vitro reduced cell viability, cell proliferation and induced apoptosis. Among the targets downregulated by miR-34a in human medulloblastoma cells were NMYC and SIRT1. Activation of the Shh pathway by targeted overexpression of SmoA1 causes medulloblastoma in mice, which is dependent on the presence and upregulation of NMYC. Analysis of miR-34a in ND2:SmoA1-derived medulloblastomas revealed significant suppression of miR-34a compared to normal cerebellum. Crossbreeding these mice with miR-34a knockout mice significantly accelerated medulloblastoma growth in mice deficient for miR-34a. Interestingly, NMYC and SIRT1 were highly expressed in medulloblastomas derived from these mice. We here demonstrate that miR-34a is dispensable for normal development, but that its loss accelerates medulloblastoma. Strategies aiming to re-express miR-34a in tumors could therefore represent an efficient therapy option.
Project description:Human hypopharygeal squamous cell carcinoma (HSCC) is a common head and neck cancer with a poor prognosis in advanced stages. Determining genes associated with transferring in HSCC could provide new targets and therapeutic strategies. We performed single-cell RNA sequencing of hypopharyngeal carcinoma and lymphoid metastases from five patients with hypopharyngeal squamous cell carcinoma.
Project description:To clarify the effect of miRNAs, we carried out a gene expression microarray analysis using GIST-T1 cells transfected with a miR-34a mimic or a negative control. We found that 2,621 probe sets (1,933 unique genes) were downregulated (>1.5-fold) by ectopic miR-34a expression, including PDGFRA gene which was previously reported as a miR-34a target gene.
Project description:Altered by defects in p53, epigenetic silencing, and genomic loss, the microRNA miR-34a represents one of the most clinically relevant tumor-suppressive microRNAs. Without question, a striking number of patients with cancer would benefit from miR-34a replacement, if poor miR-34a stability, non-specific delivery, and delivery-associated toxicity could be overcome. Here, we highlight a fully modified version of miR-34a (FM-miR-34a) that overcomes these hurdles when conjugated to a synthetically simplistic ligand. FM-miR-34a is orders of magnitude more stable than a partially modified version, without compromising its activity, leading to stronger repression of a greater number of miR-34a targets. FM-miR-34a potently inhibited proliferation and invasion, and induced sustained downregulation of endogenous target genes for >120 hours following in vivo delivery. In vivo targeting was achieved through conjugating FM-miR-34a conjugated to folate (FM-FolamiR-34a), which inhibited tumor growth leading to complete cures in some mice. These results have the ability to revitalize miR-34a as an anti-cancer agent, providing a strong rationale for clinical testing.