Project description:To investigate the molecular mechanism of Msi1 in breast cancer metastasis, we performed transcriptome profiling at 16 weeks of primary tumor samples between ctrl and Msi1 cko mice, We performed a pathway enrichment analysis of the transcriptome data, the enriched KEGG pathways are mostly related to cellular adhesion, such as Focal adhesion, cell adhesion molecular (CAM), ECM-receptor interaction and regulation of actin cytoskeleton, which are closely related to the formation of invadopodia.
Project description:Analysis of testis-specific over-expression of Musashi-1 and Musashi-2 at gene expression level. The hypothesis tested in the present study was that testis-specific over-expression of Musashi-1/Musashi-2 would result in differential gene expression profiles from the Wildtype control. Results provide important information of the genes affected by Musashi-2 overexpression during spermatogenesis.
Project description:Analysis of testis-specific over-expression of Musashi-1 and Musashi-2 at gene expression level. The hypothesis tested in the present study was that testis-specific over-expression of Musashi-1/Musashi-2 would result in differential gene expression profiles from the Wildtype control. Results provide important information of the genes affected by Musashi-2 overexpression during spermatogenesis. Total RNA obtained from whole adult testis of transgenic testis-specfic Musashi-1 and Musashi-2 overexpression mice compared to Wildtype (control) littermates. 4 replicates, 16 samples, 2 comparisons: Wt (Musashi-1) vs. TgMsi1 & Wt (Musashi-2) vs. TgMsi2
Project description:PTEN encodes a tumor suppressor with lipid and protein phosphatase activities whose dysfunction has been implicated in melanomagenesis; less is known about how its phosphatases regulate melanoma metastasis. We show that PTEN expression negatively correlates with metastatic progression in human melanoma samples and a PTEN-deficient mouse melanoma model. Wildtype PTEN expression inhibited melanoma cell invasiveness and metastasis in a dose-dependent manner, behaviors that specifically required PTEN protein phosphatase activity. PTEN phosphatase activity regulated metastasis through Entpd5. Entpd5 knockdown reduced metastasis and IGF1R levels while promoting ER stress. In contrast, Entpd5 overexpression promoted metastasis and enhanced IGF1R levels, while reducing ER stress. Moreover, Entpd5 expression was regulated by the ER stress sensor ATF6. Altogether, our data show that PTEN phosphatase activity inhibits metastasis by negatively regulating the Entpd5/IGF1R pathway through ATF6, thereby identifying novel candidate therapeutic targets for the treatmtreatingwith PTEN mutant melanoma.
Project description:RNA binding proteins (RBPs) are key regulators of normal and pathological gene expression. Small molecules targeting RBP-RNA interactions are a rapidly emerging class of therapeutics. Ro-08-2750 (Ro) was previously identified as a competitive inhibitor of Musashi-RNA interactions. Here we show Ro potently inhibits steroidogenesis and viability independent of Musashi-2 in multiple cell lines. We identified Ro-interacting proteins using an unbiased proteome-wide approach. Other RBPs were a prominent class of Ro-interacting proteins and leveraging large-scale ENCODE data we found a subset of these phenocopy Ro inhibition. We provide a general framework for validating the specificity and identifying targets of RBP inhibitors in a cellular context.
Project description:This SuperSeries is composed of the following subset Series: GSE16432: MSI2 regulates hematopoiesis and accelerates leukemogenesis GSE22773: Musashi 2 regulates normal hematopoiesis and accelerates leukemogenesis (LK and MS12-inducible) GSE22774: Musashi 2 regulates normal hematopoiesis and accelerates leukemogenesis (LSK and LK) GSE22775: Musashi 2 regulates normal hematopoiesis and accelerates leukemogenesis (Leukemia cell lines) Refer to individual Series
Project description:The Musashi family of mRNA translational regulators control both physiological and pathological stem cell self-renewal primarily by repressing targets that promote differentiation. In response to differentiation cues, Musashi can switch from a repressor to an activator of target mRNA translation. However, the molecular events that distinguish Musashi-mediated translational activation from repression are not understood. We have previously reported that Musashi function is required for the maturation of Xenopus oocytes, and specifically for translational activation of specific dormant maternal mRNAs. Here, we employed mass spectrometry to identify cellular factors necessary for Musashi-dependent mRNA translational activation. We report a requirement for association of Musashi1 with the embryonic poly(A) binding protein (ePABP) or the canonical somatic cell poly(A) binding protein PABPC1 for activation of Musashi target mRNA translation. Co-immunoprecipitation studies demonstrated an increased Musashi1 interaction with ePABP during oocyte maturation. Attenuation of endogenous ePABP activity severely compromised Musashi function, preventing downstream signaling and blocking oocyte maturation. Recovery of Musashi-dependent mRNA translational activation and maturation of ePABP attenuated oocytes was achieved through ectopic expression of either ePABP or PABPC1. Consistent with the findings in Xenopus oocytes, PABPC1 remained associated with Musashi under conditions of Musashi target mRNA de-repression and translation during mammalian stem cell differentiation. Since association of Musashi1 with poly(A) binding proteins has previously only been implicated in repression of Musashi target mRNAs, our findings reveal distinct context-dependent roles for the interaction of Musashi with poly[A] binding protein family members in response to extracellular cues that control cell fate.
Project description:Tumor metastasis remains the major cause of cancer-related death, but its molecular basis is still not well understood. Here we uncovered a splicing-mediated pathway that is essential for breast cancer metastasis. We show that the RNA-binding protein hnRNPM promotes breast cancer metastasis by activating the switch of alternative splicing that occurs during epithelial-mesenchymal transition (EMT). Genome-wide deep sequencing analysis suggests that hnRNPM potentiates TGFb signaling and identifies CD44 as a key downstream target of hnRNPM. hnRNPM ablation prevents TGFb-induced EMT and inhibits breast cancer metastasis in mice, whereas enforced expression of the specific CD44s splice isoform overrides the loss of hnRNPM and permits EMT and metastasis. Mechanistically, we demonstrate that the ubiquitously expressed hnRNPM acts in a mesenchymal-specific manner to precisely control CD44 splice isoform switching during EMT. This restricted cell-type activity of hnRNPM is achieved by competition with ESRP1, an epithelial-splicing regulator that binds to the same cis-regulatory RNA elements and is repressed during EMT. Importantly, hnRNPM is associated with aggressive breast cancer and correlates with increased CD44s in patient specimens. These findings demonstrate a novel molecular mechanism through which tumor metastasis is endowed by the hnRNPM-mediated splicing program. RNAseq for control, hnRNPM siRNA treated lung metastatic LM2 clonal line, derived from the mesenchymal MDA-MB-231 cells