ABSTRACT: We expressed a constitutively active mutant of MEK5 (MEK5D) in human primary endothelial cells (EC) to study the transcriptional and functional responses to Erk5 activation under static conditions. HUVEC were infected with either empty vector or constitutively active MEK5D and RNA was processed for microarray analysis 40 h post infection.
Project description:We expressed a constitutively active mutant of MEK5 (MEK5D) in human primary endothelial cells (EC) to study the transcriptional and functional responses to Erk5 activation under static conditions.
Project description:To investigate the gene expression in dendritic cells after treating hemiphilic mice with HBSS, plasma derived or recombinant factor VIII Gene expression in dendritic cells were measured 24 hours post treatment Hemophilic mice with treated with either (HBSS, rFVIII or pdFVIII) 24 hours post treatment the spleens were isolated and CD11+ DCs were purified. The gene expression in the DCs were then investigated by microarray studies.
Project description:We have employed a high-content microscopy screen in combination with a kinome and phosphatome-wide siRNA library to identify signaling pathways underlying an EMT of murine mammary epithelial cells and breast cancer cells. This screen identified the MEK5-ERK5 axis as a critical player in TGFb-mediated EMT. Suppression of MEK5-ERK5 signaling completely prevented the morphological and molecular changes occurring during a TGFb-induced EMT and, conversely, forced highly metastatic breast cancer cells into a differentiated epithelial state. Inhibition of MEK5-ERK5 signaling also repressed breast cancer cell migration and invasion and substantially reduced lung metastasis without affecting primary tumor growth. The results suggest that the MEK5-ERK5 signaling axis plays an important role in the induction and maintenance of breast cancer cell migration and invasion and thus represents an exploitable target for the pharmacological inhibition of cancer cell metastasis.
Project description:Mitogen/extracellular signal-regulated kinase kinase-5 (MEK5) belongs to the family of MAP kinases. It is activated by the upstream kinases MEKK2 and MEKK3. MEK5, in turn, phosphorylates and activates extracellular signal-regulated kinase 5 (ERK5) at Thr218/Tyr220. MEK5/ERK5 pathway plays a pivotal role in tumor initiation and progression, including prostate cancer. MEK5 protein is overexpressed in prostate cancer cells compared with normal cells and MEK5 levels are correlated with prostate cancer metastasis. Global gene expression was determined in PC3 cells stably expressing a scrambled (control) shRNA or MEK5 shRNA using the Agilent Mouse Whole Genome microarrays. Gene ontology and pathway analysis of differentially expressed genes using Ingenuity Pathway Analysis and gene set enrichment analysis (GSEA) revealed MEK5 knockdown attenuates a number or critical signaling pathways required for prostate tumor growth and progression.
Project description:Mitogen/extracellular signal-regulated kinase kinase-5 (MEK5) belongs to the family of MAP kinases. It is activated by the upstream kinases MEKK2 and MEKK3. MEK5, in turn, phosphorylates and activates extracellular signal-regulated kinase 5 (ERK5) at Thr218/Tyr220. MEK5/ERK5 pathway plays a pivotal role in tumor initiation and progression, including prostate cancer. MEK5 protein is overexpressed in prostate cancer cells compared with normal cells and MEK5 levels are correlated with prostate cancer metastasis. Global gene expression was determined in DU145 cells stably expressing a scrambled (control) shRNA or MEK5 shRNA using the Agilent Mouse Whole Genome microarrays. Gene ontology and pathway analysis of differentially expressed genes using Ingenuity Pathway Analysis and gene set enrichment analysis (GSEA) revealed MEK5 knockdown attenuates a number or critical signaling pathways required for prostate tumor growth and progression.
Project description:Targeted deletion of TRAF7 revealed that it is a crucial part of shear stress-responsive MEKK3-MEK5-ERK5 signaling pathway induced in endothelial cells by blood flow. Similarly, to Mekk3-, Mek5- or Erk5-deficient mice, Traf7-deficient embryos died in utero around midgestation due to impaired endothelial cell integrity. They displayed significantly lower expression of transcription factor Klf2, an essential regulator of vascular hemodynamic forces downstream of the MEKK3-MEK-ERK5 signaling pathway. Deletion of Traf7 in endothelial cells of postnatal mice was also associated with severe cerebral hemorrhage. Here, we show that besides MEKK3 and MEK5, TRAF7 associates with a planar cell polarity protein SCRIB. SCRIB binds with an N-terminal region of TRAF7, while MEKK3 associates with the C-terminal WD40 domain. Downregulation of TRAF7 as well as SCRIB inhibited fluid shear stress-induced phosphorylation of ERK5 in cultured endothelial cells. These findings suggest that TRAF7 and SCRIB may comprise an upstream part of the MEKK3-MEK5-ERK5 signaling pathway. Objective: to present first in vivo experimental evidence of TRAF7 function by using global and endothelium-specific TRAF7 knockout mice and comparing transcriptomes of developing embryos.
Project description:To investigate the function of MEK5/ERK5 in the regulation of hPSC pluripotency, we processed MAP2K5DD (MEK5DD) overexpression H1 ESC line.
Project description:Cancer cell motility and invasiveness are fundamental characteristics of the malignant phenotype and are regulated through diverse signaling networks involving kinases and transcription factors. In this study, we identify a nuclear hormone receptor (ERα)-protein kinase (ERK5)-cofilin (CFL1) network that specifies the degree of breast cancer cell aggressiveness through coupling of actin reorganization and hormone receptor-mediated transcription. Using dominant negative and constitutively active forms, as well as small molecule inhibitors of ERK5 and MEK5, we show that hormone activation of estrogen receptor-α determines the nuclear versus cytoplasmic localization of the MAPK family member ERK5, which functions as a coregulator of ERα-gene transcription. Notably, ERK5 works with the actin remodeling protein, CFL1, and upon hormone exposure both became localized to transcription factories in the nucleus, verified by immunofluorescence and proximity ligation assays. Both factors facilitated PAF1 recruitment to the RNA Pol II complex and both ERK5 and CFL1 were required for regulation of gene transcription. By contrast, in cells lacking ERα, ERK5 and CFL1 localized to cytoplasmic membrane regions of high actin remodeling, promoting cell motility and invasion, thereby revealing a mechanism likely to contribute to the generally poorer prognosis of ERα-negative breast cancers. Our study uncovers the dynamic interplay of nuclear receptor-mediated transcription and actin reorganization in phenotypes of breast cancer aggressiveness, and highlights new prognostic biomarkers and suggests novel approaches for developing targeted therapies to moderate cancer aggressiveness. MCF-7 human breast adenocarcinoma cells were tranfected with control, and ERK5 siRNA for 72 hours and treated with 0.1% EtOH (Vehicle) or 10 nM E2 for 24 hours, and cDNA microarray analyses were carried out using Affymetrix [HG-U133A_2] Affymetrix Human Genome U133A 2.0 Array. siRNA knock-down, ligand treatment
Project description:Cancer cell motility and invasiveness are fundamental characteristics of the malignant phenotype and are regulated through diverse signaling networks involving kinases and transcription factors. In this study, we identify a nuclear hormone receptor (ERα)-protein kinase (ERK5)-cofilin (CFL1) network that specifies the degree of breast cancer cell aggressiveness through coupling of actin reorganization and hormone receptor-mediated transcription. Using dominant negative and constitutively active forms, as well as small molecule inhibitors of ERK5 and MEK5, we show that hormone activation of estrogen receptor-α determines the nuclear versus cytoplasmic localization of the MAPK family member ERK5, which functions as a coregulator of ERα-gene transcription. Notably, ERK5 works with the actin remodeling protein, CFL1, and upon hormone exposure both became localized to transcription factories in the nucleus, verified by immunofluorescence and proximity ligation assays. Both factors facilitated PAF1 recruitment to the RNA Pol II complex and both ERK5 and CFL1 were required for regulation of gene transcription. By contrast, in cells lacking ERα, ERK5 and CFL1 localized to cytoplasmic membrane regions of high actin remodeling, promoting cell motility and invasion, thereby revealing a mechanism likely to contribute to the generally poorer prognosis of ERα-negative breast cancers. Our study uncovers the dynamic interplay of nuclear receptor-mediated transcription and actin reorganization in phenotypes of breast cancer aggressiveness, and highlights new prognostic biomarkers and suggests novel approaches for developing targeted therapies to moderate cancer aggressiveness.
Project description:Small cell lung cancer (SCLC), accounts for about 15 percent of all lung cancers, is a neuroendocrine type of carcinoma and is incredibly aggressive, with a dire diagnosis of 5% survival at 5 years. FDA-approved therapies for this disease are almost exclusively limited to chemotherapy and radiotherapy, to which resistance arises within months. Despite global sequencing efforts, few activating mutations have been discovered in SCLC tumors, and targetable alterations account for very small subsets of patients. Due to this lack of a strong oncogenic driver for conventional targeted therapy, SCLC has the potential to benefit from non-oncogene-addiction-based therapeutic approaches. We therefore focused on finding novel non-mutated pathways which could be targetable in SCLC. Restricting our search to kinases, a highly-targetable group of enzymes, we elucidated the active kinome of SCLC and upon identifying MEK5 as a SCLC-specific active kinase, further investigated the role of the MEK5-ERK5 kinase axis in this tumor type. We found that reduction in this axis in both human and murine SCLC cells causes increased susceptibility to apoptosis, and decreased subcutaneous tumor growth in vivo. Transcriptomic analysis of MEK5 and ERK5-knockdown cells showed downregulation of lipid metabolism pathways and SREBP target genes. Based on targeted lipidomics analyses of these same cells, which showed downregulated cholesterol ester species, we focused on the mevalonate arm of the SREBP pathway.