Homo sapiens
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PROVIDER: PRJNA271112 | ENA |
REPOSITORIES: ENA
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Project description:Canonical Wnt signaling plays an important role in development and disease, regulating transcription of target genes and stabilizing many proteins phosphorylated by Glycogen Synthase Kinase 3 (GSK3). We observed that the MiT family of transcription factors, which includes the melanoma oncogene MITF and the lysosomal master regulator TFEB, had the highest phylogenetic conservation of three consecutive putative GSK3 phosphorylation sites in animal proteomes. This prompted us to examine the relationship between MITF, endolysosomal biogenesis and Wnt signaling. Here we report that MITF expression levels correlated with the expression of a large subset of lysosomal genes in melanoma cell lines. MITF expression in the Tetracycline-inducible C32 melanoma model caused a marked increase in vesicular structures, and increased expression of late endosomal proteins such as Rab7, LAMP1, and CD63. These late endosomes were not functional lysosomes as they were less active in proteolysis, yet were able to concentrate Axin1, phospho-LRP6, phospho-β-Catenin, and GSK3 in the presence of Wnt ligands. This relocalization significantly enhanced Wnt signaling by increasing the number of multivesicular bodies (MVBs) into which the Wnt signalosome/destruction complex becomes localized upon Wnt signaling. We also show that the MITF protein was stabilized by Wnt signaling, through the novel C-terminal GSK3 phosphorylations identified here. MITF stabilization caused an increase in MVB biosynthesis, which in turn increased Wnt signaling, generating a positive feed-back loop that may function during the proliferative stages of melanoma. The results underscore the importance of misregulated endolysosomal biogenesis in Wnt signaling and cancer. Expression of selected Lysosomal genes and CLEAR element plus MITF were compared in 51 melanoma cell lines to a mixed reference pool containing equal amounts of 47 melanoma cell lines.
2014-12-24 | E-GEOD-64497 | biostudies-arrayexpress
Project description:Canonical Wnt signaling plays an important role in development and disease, regulating transcription of target genes and stabilizing many proteins phosphorylated by Glycogen Synthase Kinase 3 (GSK3). We observed that the MiT family of transcription factors, which includes the melanoma oncogene MITF and the lysosomal master regulator TFEB, had the highest phylogenetic conservation of three consecutive putative GSK3 phosphorylation sites in animal proteomes. This prompted us to examine the relationship between MITF, endolysosomal biogenesis and Wnt signaling. Here we report that MITF expression levels correlated with the expression of a large subset of lysosomal genes in melanoma cell lines. MITF expression in the Tetracycline-inducible C32 melanoma model caused a marked increase in vesicular structures, and increased expression of late endosomal proteins such as Rab7, LAMP1, and CD63. These late endosomes were not functional lysosomes as they were less active in proteolysis, yet were able to concentrate Axin1, phospho-LRP6, phospho-β-Catenin, and GSK3 in the presence of Wnt ligands. This relocalization significantly enhanced Wnt signaling by increasing the number of multivesicular bodies (MVBs) into which the Wnt signalosome/destruction complex becomes localized upon Wnt signaling. We also show that the MITF protein was stabilized by Wnt signaling, through the novel C-terminal GSK3 phosphorylations identified here. MITF stabilization caused an increase in MVB biosynthesis, which in turn increased Wnt signaling, generating a positive feed-back loop that may function during the proliferative stages of melanoma. The results underscore the importance of misregulated endolysosomal biogenesis in Wnt signaling and cancer.
2014-12-24 | GSE64497 | GEO
Project description:The close integration of the MAPK, PI3K and WNT signaling pathways underpins much of development and is deregulated in cancer. In principle, combinatorial post-translational modification of key lineage–specific transcription factors would be an effective means to integrate critical signaling events. Understanding how this might be achieved is central to deciphering the impact of microenvironmental cues in development and disease. The microphthalmia associated transcription factor, MITF, plays a crucial role in the development of melanocytes, the retinal pigment epithelium, osteoclasts and mast cells, and acts as a lineage survival oncogene in melanoma. MITF coordinates survival, differentiation, cell cycle progression, cell migration, metabolism and lysosome biogenesis. Yet how the activity of this key transcription factor is controlled remains poorly understood. Here we show that GSK3b, downstream from both the PI3K and Wnt pathways, and BRAF/MAPK signaling converge to control MITF nuclear export. Phosphorylation of the melanocyte MITF-M isoform in response to BRAF/MAPK signaling primes for phosphorylation by GSK3b, a kinase inhibited by both PI3K and Wnt signaling. Dual phosphorylation, but not monophosphorylation, then promotes MITF nuclear export by activating a previously unrecognized hydrophobic export signal. Nonmelanocyte MITF isoforms exhibit poor regulation by MAPK signaling, but instead their export is controlled by mTOR. We uncover here an unanticipated mode of MITF regulation that integrates the output of key developmental and cancer-associated signaling pathways to gate MITF flux through the import-export cycle. The results have significant implications for our understanding of melanoma progression and stem cell renewal
2022-02-28 | PXD010665 | Pride
Project description:The close integration of the MAPK, PI3K, and WNT signaling pathways underpins much of development and is deregulatedin cancer. In principle, combinatorial posttranslational modification of key lineage specific transcription factors would be an effective mean stointegrate critical signaling events. Understanding how this might be achieved is central to deciphering the impact of microenvironmental cues in development and disease. The microphthalmia-associated transcription factor MITF plays a crucial role in the development of melanocytes, the retinal pigment epithelium, osteoclasts, and mast cells and acts as a lineage survival oncogene in melanoma. MITF coordinates survival, differentiation, cell-cycle progression, cell migration, metabolism, and lysosome biogenesis. However, how the activity of this key transcriptionfactoriscontrolledremainspoorlyunderstood.Here,we showthatGSK3,downstreamfromboththePI3KandWntpathways, and BRAF/MAPK signaling converge to control MITF nuclear export. Phosphorylation of the melanocyte MITF-M isoform in response to BRAF/MAPK signaling primes for phosphorylation by GSK3, a kinase inhibited by both PI3K and Wnt signaling. Dual phosphorylation, but not monophosphorylation, then promotes MITF nuclear export by activatinga previously unrecognizedhydrophobic exportsignal. NonmelanocyteMITFisoformsexhibitpoorregulationbyMAPKsignaling, but instead their export is controlled by mTOR. We uncover here an unanticipated mode of MITF regulation that integrates the output of key developmental and cancer-associated signaling pathways to gate MITF flux through the import–export cycle. The results have significant implications for our understanding of melanoma progression and stem cell renewal.
2019-11-12 | PXD010782 | Pride
Project description:The most critical stage in initiation of melanoma metastasis is the radial to vertical growth transition, yet the triggers of this transition remain elusive. We introduce a novel perspective, suggesting that the microenvironment drives melanoma metastasis independently of mutation acquisition. Here we examined the changes in microenvironment that occur during melanoma radial growth. We show that direct contact of melanoma cells with the remote epidermal layer triggers vertical invasion via Notch signaling activation, the latter serving to inhibit MITF function. Briefly, within the native Notch ligand-free microenvironment, MITF, the melanocyte lineage master regulator, binds and represses miR-222/221 promoter in an RBPJK-dependent manner. However, when radial growth brings melanoma cells into contact with distal differentiated keratinocytes that express Notch ligands, the activated Notch intracellular domain impairs MITF binding to miR-222/221 promoter. This de-repression of miR-222/221 expression triggers initiation of invasion. Our findings may direct novel prevention opportunities via targeting specific microenvironment. Two replicates of Notch-activated cells that were seeded on Delta-like-1 (DLL1) (2 ng/µl ) coated plates were compared to two replicates of cells without Notch activation. The goal of this experiment is to evaluate the changes of miRs expression in melanoma cells upon Notch signaling activation.
2015-07-30 | E-GEOD-69403 | biostudies-arrayexpress
Project description:Melanoma cells from three surgical specimens of nodular melanoma were grown as anchorage-independent melanospheres in stem cell bFGF(+)EGF(+) medium and as adherent monolayer cultures in the presence of serum. RNA from melanospheres (DMBC2s, DMBC8s, DMBC10s) and their adherent monolayer counterparts (DMBC2a, DMBC8a, DMBC10a) were hybridized to the dual-color Agilent human genome array G4450A. A transcriptome profile was generated to explore the molecules governing phenotypes of melanospheres and monolayers. We demonstrated that melanospheres contained more pigmented cells which was consistent with higher expression of MITF and MITF-dependent genes responsible for differentiation, including TYR, TYRP1, MLANA and DCT. Expression of MITF-dependent BIRC7, BCL2 and BCL2A1 was reduced in monolayers, thus limiting the anti-apoptotic protection. The enhanced activity of MITF shown as the elevated expression of 74 MITF-dependent genes in melanospheres, identified MITF as a central regulator of this phenotype. Importantly, our study revealed that MITF and MITF-dependent genes were expressed in melanospheres at similar levels as in original tumors, much higher than in monolayers. The reduced MITF level in monolayers might be partially explained by suppression of the Wnt/beta-catenin pathway. Differential expression of Wnt/beta-catenin pathway components and target genes in melanospheres and monolayers points to strong influence of the microenvironment on the functional outcome of Wnt/beta-catenin pathway in melanoma, including differentiation, survival, proliferation and invasiveness. Silencing of the Wnt inhibitor DKK1 in monolayers increased the percentage of clonogenic cells. In summary, melanospheres more accurately mirrored the morphology, heterogeneity and gene expression profiles of original tumors than monolayers. Our study demonstrates the feasibility of utilizing melanospheres to unravel the molecular pathways sustaining melanoma heterogeneity and potentially to select compounds with anticancer activities.
2014-06-03 | E-MTAB-1869 | biostudies-arrayexpress
Project description:Wnt-signaling potentiates nevogenesis.
| PRJNA202396 | ENA
Project description:The most critical stage in initiation of melanoma metastasis is the radial to vertical growth transition, yet the triggers of this transition remain elusive. We introduce a novel perspective, suggesting that the microenvironment drives melanoma metastasis independently of mutation acquisition. Here we examined the changes in microenvironment that occur during melanoma radial growth. We show that direct contact of melanoma cells with the remote epidermal layer triggers vertical invasion via Notch signaling activation, the latter serving to inhibit MITF function. Briefly, within the native Notch ligand-free microenvironment, MITF, the melanocyte lineage master regulator, binds and represses miR-222/221 promoter in an RBPJK-dependent manner. However, when radial growth brings melanoma cells into contact with distal differentiated keratinocytes that express Notch ligands, the activated Notch intracellular domain impairs MITF binding to miR-222/221 promoter. This de-repression of miR-222/221 expression triggers initiation of invasion. Our findings may direct novel prevention opportunities via targeting specific microenvironment.
2015-07-30 | GSE69403 | GEO
Project description:MITF is the master regulator of the melanocyte lineage and a melanoma lineage oncogene. It controls a wide range of target genes fulfilling many distinct functions, but relatively little is known about how its DNA-binding is regulated to select the correct target genes. The datasets presented here were used investigate the effects of MAPK signaling-induced MITF-acetylation on MITF activity in melanoma cells through ChIP-Seq of wild-type and acetyl-mutant MITF.
2021-02-12 | GSE77437 | GEO
Project description:To determine the role of PRL3 in gene regulation, empty vector or HA-tagged PRL3 was stably expressed in cultured human melanoma A375 cells. ChIP-seq was used to determine the impact of increased PRL3 expression on the genome-wide distribution of RNA Polymerase II (Total/Ser5-Phosphorylated/Ser2-Phosphorylated), MITF and DDX21. In combination with transcriptional analysis (4sU-seq; GEO accession - GSE127855), this study demonstrated that PRL3 overexpression leads to reduced RNA polymerase processivity at a subset of so called 'restricted' genes which are enriched for endolysosomal functions.
2020-07-20 | GSE149929 | GEO