MicroRNA-21-induced loss of Junctional Adhesion Molecule-A promotes activation of oncogenic pathways, progression and metastasis in colorectal cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE149658 | GEO | 2021/10/13
REPOSITORIES: GEO
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Project description:Junctional Adhesion Molecule-A (JAM-A), expressed on the surface of myeloid cells, is required for extravasation at sites of inflammation and may also modulate macrophage activation. Myeloid cell infiltration is a common feature of tumors that drives disease progression, but the function of JAM-A in this phenomenon and its impact on cancer-associated myeloid cells is little understood. Here we show that systemic cancer-induced inflammation in mice enhanced JAM-A expression in an IL1β-dependent manner specifically on circulating monocytes. However, using myeloid-specific JAM-A-deficient mice, we found that JAM-A was dispensable for recruitment of monocytes and other myeloid cells to tumors, in contrast to its reported role in inflammation. Single-cell RNA sequencing revealed that the loss of JAM-A did not influence the transcriptional reprogramming of tumor-infiltrating myeloid cells. Overall, our results support the notion that cancer-associated inflammation can modulate the phenotype of circulating immune cells and we demonstrate that tumors can bypass the requirement of JAM-A for myeloid cell recruitment.
2022-08-04 | GSE210226 | GEO
Project description:Endothelial cells form a barrier between the components present in the blood and the underlying tissue. Essential to formation of this barrier are junctional complexes present between cells. These complexes are dynamic, tightly regulated and remodel during key physiological processes such as inflammation, angiogenesis and development to allow passage of molecules, cells and movement of endothelial cells. One such junctional protein, Jam-C, is involved in the pathology of a number of inflammatory disease states and its inhibition in vitro and in vivo results in aberrant forms of leukocyte migration, dysregulated angiogenesis and inhibition of cell migration. Intracellular trafficking has been shown to be a general means of regulating the function of junctional proteins but its role in Jam-C function is unclear. Using a combination of receptor mutagenesis, HRP and APEX-2 proximity labelling alongside light and electron microscopy, we here characterise the dynamics and route of Jam-C trafficking. Rather than trafficking with junctional proteins associated with the inflammatory process, Jam-C co-traffics with receptors associated with changes in permeability such as VE-Cadherin, NRP-1 and 2. We show that Jam-C becomes ubiquitylated by the E-3 ligase CBL and that this post translational modification controls the likelihood of its degradation in the lysosomes or its recycling back to the cell surface. Finally, we show that Jam-C trafficking is essential for some of the endothelial functions of Jam-C.
2019-11-06 | PXD013003 | Pride
Project description:MicroRNA-21-induced loss of Junctional Adhesion Molecule-A promotes activation of oncogenic pathways, progression and metastasis in colorectal cancer
| PRJNA629564 | ENA
Project description:Hepatocytes are polarized epithelial cells whose function depends upon their ability to distinguish between the apical and basolateral surfaces that are located at intercellular tight junctions. It has been proposed that the signaling cascades that originate at these junctions influence cellular activity by controlling gene expression in the cell nucleus. To assess the validity of this proposal with regard to hepatocytes, we depleted expression of the tight junction protein junctional adhesion molecule-A (JAM-A) in the HepG2 human hepatocellular carcinoma cell line. Reduction of JAM-A resulted in a striking change in cell morphology, with cells forming single-layered sheets instead of the normal multi-layered clusters. In the absence of JAM-A, other tight junction proteins were mislocalized, and canaliculi, which form the apical face of the hepatocyte, were consequently absent. While most changes in gene expression were modest, there was a strong transcriptional induction of the adherens junction protein E-cadherin in cells with reduced levels of JAM-A. This increase in E-cadherin was partially responsible for the observed alterations in cell morphology and mislocalization of tight junction proteins. We therefore propose that we have uncovered a novel mechanism for crosstalk between specific components of tight and adherens junctions that can be utilized to regulate adhesion between hepatic cells and to maintain hepatocyte cell polarity. Experiment Overall Design: HepG2 cells were transduced with lentiviruses and stably selected using puromycin. Comparison of four controls and five JAM-A knockdown samples.
2008-06-14 | E-GEOD-6080 | biostudies-arrayexpress
Project description:Junctional adhesion molecules (JAMs) play a critical role in cell permeability, polarity and migration. JAM-A, a key protein of the JAM family, is altered in a number of conditions including cancer; however, consequences of JAM-A dysregulation on carcinogenesis appear to be tissue dependent and organ dependent with significant implications for the use of JAM-A as a biomarker or therapeutic target. Here, we test the expression and prognostic role of JAM-A downregulation in primary and metastatic colorectal cancer (CRC) (n = 947). We show that JAM-A downregulation is observed in ~60% of CRC and correlates with poor outcome in four cohorts of stages II and III CRC (n = 1098). Using JAM-A knockdown, re-expression and rescue experiments in cell line monolayers, 3D spheroids, patient-derived organoids and xenotransplants, we demonstrate that JAM-A silencing promotes proliferation and migration in 2D and 3D cell models and increases tumour volume and metastases in vivo. Using gene-expression and proteomic analyses, we show that JAM-A downregulation results in the activation of ERK, AKT and ROCK pathways and leads to decreased bone morphogenetic protein 7 expression. We identify MIR21 upregulation as the cause of JAM-A downregulation and show that JAM-A rescue mitigates the effects of MIR21 overexpression on cancer phenotype. Our results identify a novel molecular loop involving MIR21 dysregulation, JAM-A silencing and activation of multiple oncogenic pathways in promoting invasiveness and metastasis in CRC.
| S-EPMC8481293 | biostudies-literature
Project description:Junctional adhesion molecule-A (JAM-A) is a transmembrane component of tight junctions that has been proposed to play a role in regulating epithelial cell adhesion and migration, yet mechanistic structure-function studies are lacking. Although biochemical and structural studies indicate that JAM-A forms cis-homodimers, the functional significance of dimerization is unclear. Here, we report the effects of cis-dimerization-defective JAM-A mutants on epithelial cell migration and adhesion. Overexpression of dimerization-defective JAM-A mutants in 293T cells inhibited cell spreading and migration across permeable filters. Similar inhibition was observed with using dimerization-blocking antibodies. Analyses of cells expressing the JAM-A dimerization-defective mutant proteins revealed diminished beta1 integrin protein but not mRNA levels. Further analyses of beta1 protein localization and expression after disruption of JAM-A dimerization suggested that internalization of beta1 integrin precedes degradation. A functional link between JAM-A and beta1 integrin was confirmed by restoration of cell migration to control levels after overexpression of beta1 integrin in JAM-A dimerization-defective cells. Last, we show that the functional effects of JAM dimerization require its carboxy-terminal postsynaptic density 95/disc-large/zonula occludins-1 binding motif. These results suggest that dimerization of JAM-A regulates cell migration and adhesion through indirect mechanisms involving posttranscriptional control of beta1 integrin levels.
| S-EPMC2366836 | biostudies-literature
Project description:Junctional Adhesion Molecule-A is dispensable for myeloid cell recruitment and diversification in the tumor microenvironment
| PRJNA864799 | ENA
Project description:Hepatocytes are polarized epithelial cells whose function depends upon their ability to distinguish between the apical and basolateral surfaces that are located at intercellular tight junctions. It has been proposed that the signaling cascades that originate at these junctions influence cellular activity by controlling gene expression in the cell nucleus. To assess the validity of this proposal with regard to hepatocytes, we depleted expression of the tight junction protein junctional adhesion molecule-A (JAM-A) in the HepG2 human hepatocellular carcinoma cell line. Reduction of JAM-A resulted in a striking change in cell morphology, with cells forming single-layered sheets instead of the normal multi-layered clusters. In the absence of JAM-A, other tight junction proteins were mislocalized, and canaliculi, which form the apical face of the hepatocyte, were consequently absent. While most changes in gene expression were modest, there was a strong transcriptional induction of the adherens junction protein E-cadherin in cells with reduced levels of JAM-A. This increase in E-cadherin was partially responsible for the observed alterations in cell morphology and mislocalization of tight junction proteins. We therefore propose that we have uncovered a novel mechanism for crosstalk between specific components of tight and adherens junctions that can be utilized to regulate adhesion between hepatic cells and to maintain hepatocyte cell polarity. Keywords: HepG2 cells
2007-07-01 | GSE6080 | GEO
Project description:The apical junctional complex (AJC), composed of tight junctions and adherens junctions, is essential for maintaining epithelial barrier function. Since cigarette smoking and chronic obstructive pulmonary disease (COPD), the major smoking-induced disease, are both associated with increased lung epithelial permeability, we hypothesized that smoking alters the transcriptional program regulating AJC integrity in the small airway epithelium (SAE), the primary site of pathological changes in COPD. Transcriptome analysis revealed a global down-regulation of physiological AJC gene expression in the SAE of healthy smokers (n=53) compared to healthy nonsmokers (n=59), an observation associated with changes in molecular pathways regulating epithelial differentiation such as PTEN signaling and accompanied by induction of cancer-related AJC genes. Genome-wide co-expression analysis identified a smoking-sensitive AJC transcriptional network. The overall expression of AJC-associated genes was further decreased in COPD smokers (n=23). Exposure of human airway epithelial cells to cigarette smoke extract in vitro resulted in down-regulation of several AJC-related genes, accompanied by decreased transepithelial resistance. Thus, cigarette smoking alters the AJC gene expression architecture in the human airway epithelium, providing a molecular basis for the dysregulation of airway epithelial barrier function during the development of smoking-induced lung disease. The apical junctional complex (AJC), composed of tight junctions and adherens junctions, is essential for maintaining epithelial barrier function. Since cigarette smoking and chronic obstructive pulmonary disease (COPD), the major smoking-induced disease, are both associated with increased lung epithelial permeability, we hypothesized that smoking alters the transcriptional program regulating AJC integrity in the small airway epithelium (SAE), the primary site of pathological changes in COPD. In this study, microarray analysis of the SAE obtained from 53 healthy nonsmokers, 59 healthy smokers, and 23 smokers with COPD was performed to determine physiological AJC gene expression architecture in the SAE and its modification by cigarette smoking and during the development of COPD.
2011-06-27 | E-GEOD-20257 | biostudies-arrayexpress
Project description:Diverse families of viruses bind immunoglobulin superfamily (IgSF) proteins located in tight junctions (TJs) and adherens junctions of epithelium and endothelium. However, little is known about the roles of these receptors in the pathogenesis of viral disease. Junctional adhesion molecule-A (JAM-A) is an IgSF protein that localizes to TJs and serves as a receptor for mammalian reovirus. We inoculated wild-type (WT) and isogenic JAM-A(-/-) mice perorally with reovirus and found that JAM-A is dispensable for viral replication in the intestine but required for systemic dissemination. Reovirus replication in the brain and tropism for discrete neural regions are equivalent in WT and JAM-A(-/-) mice following intracranial inoculation, suggesting a function for JAM-A in reovirus spread to extraintestinal sites. JAM-A promotes reovirus infection of endothelial cells, providing a conduit for the virus into the bloodstream. These findings indicate that a broadly expressed IgSF viral receptor specifically mediates hematogenous dissemination in the host.
| S-EPMC2642927 | biostudies-literature