Junctional adhesion molecule C (JAM-C) dimerization aids cancer cell migration and metastasis

Junctional Adhesion Molecule (JAM)-C recruitment of Pard3 and drebrin to cell contacts initiates neuron-glia recognition and layer-specific cell sorting in developing cerebella

Sorting maturing neurons into distinct layers is critical for brain development, with disruptions leading to neurological disorders and pediatric cancers. Lamination coordinates where, when, and how cells interact, facilitating events that direct migrating neurons to their destined positions within emerging neural networks and control the wiring of connections in functional circuits. While the role of adhesion molecule expression and presentation in driving adhesive recognition during neuronal migration along glial fibers is recognized, the mechanisms by which the spatial arrangement of these molecules on the cell surface dictates adhesive specificity and translates contact-based external cues into intracellular responses like polarization and cytoskeletal organization remain largely unexplored. We used the cerebellar granule neuron (CGN) system to demonstrate that JAM-C receptor cis-binding on the same cell and trans-binding to neighboring cells controls the recruitment of the Pard3 polarity protein and drebrin microtubule-actin crosslinker at CGN to glial adhesion sites, complementing previous studies that showed Pard3 controls JAM-C exocytic surface presentation. Leveraging advanced imaging techniques, specific probes for cell recognition, and analytical methods to dissect adhesion dynamics, our findings reveal: 1) JAM-C cis or trans mutants result in reduced adhesion formation between CGNs and cerebellar glia, 2) these mutants exhibit delayed recruitment of Pard3 at the adhesion sites, and 3) CGNs with JAM-C mutations experience postponed sorting and entry into the cerebellar molecular layer (ML). By developing a conditional system to image adhesion components from two different cells simultaneously, we made it possible to investigate the dynamics of cell recognition on both sides of neuron-glial contacts and the subsequent recruitment of proteins required for CGN migration. This system and an approach that calculates local correlation based on convolution kernels at the cell adhesions site revealed that CGN to CGN JAM recognition preferentially recruits higher levels of Pard3 and drebrin than CGN to glia JAM recognition. The long latency time of CGNs in the inner external germinal layer (EGL) can be attributed to the combined strength of CGN-CGN contacts and the less efficient Pard3 recruitment by CGN-BG contacts, acting as gatekeepers to ML entry. As CGNs eventually transition to glia binding for radial migration, our research demonstrates that establishing permissive JAM-recognition sites on glia via cis and trans interactions of CGN JAM-C serves as a critical temporal checkpoint for sorting at the EGL to ML boundary. This mechanism integrates intrinsic and extrinsic cellular signals, facilitating heterotypic cell sorting into the ML and dictating the precise spatial organization within the cerebellar architecture.

Screening of Cu4 O3 NPs efficacy and its anticancer potential against cervical cancer

Cu4 O3 is the least explored copper oxide, and its nanoformulation is anticipated to have important therapeutic potential especially against cancer. The current study aimed to biosynthesize Cu4 O3 nanoparticles (NPs) using an aqueous extract of pumpkin seeds and evaluate its antiproliferative efficacy against cervical cells after screening on different cancer cell lines. The obtained NPs were characterized by different spectroscopic analyses, such as UV-vis, thermogravimetric, energy dispersive X-ray, and Fourier-transform infrared spectroscopy (FTIR). In addition, high-resolution transmission electron microscopes (HR-TEM) were used to observe the morphology of the biosynthesized NPs. The UV-vis spectra showed a peak at around 332 nm, confirming the formation of Cu4 O3 NPs. Moreover, FTIR and TAG analyses identified the presence of various bioactive phytoconstituents that might have worked as capping and stabilization agents and comparative stable NPs at very high temperatures, respectively. The HR-TEM data showed the spherical shape of Cu4 O3 NPs in the range of 100 nm. The Cu4 O3 NPs was screened on three different cancer cell lines viz., Hela, MDA-MB-231, and HCT-116 using cytotoxicity (MTT) reduction assay. In addition, Vero was taken as a normal epithelial (control) cell. The high responsive cell line in terms of least IC50 was further assessed for its anticancer potential using a battery of biological tests, including morphological alterations, induction of apoptosis/ROS generation, regulation of mitochondrial membrane potential (MMP), and suppression of cell adhesion/migration. Vero cells (control) showed a slight decline in % cell viability even at the highest tested Cu4 O3 NPs concentration. However, all the studied cancer cells viz., MDA-MB-231, HCT 116, and HeLa cells showed a dose-dependent decline in cell viability after the treatment with Cu4 O3 NPs with a calculated IC50 value of 10, 11, and 7.2 µg/mL, respectively. Based on the above data, Hela cells were chosen for further studies, that showed induction of apoptosis from 3.5 to 9-folds by three different staining techniques acridine orange/ethidium bromide (AO/EB), 4',6-diamidino-2-phenylindole (DAPI), and propidium iodide (PI). The enhanced production of reactive oxygen species (>3.5-fold), modulation in MMP, and suppression of cell adhesion/migration were observed in the cells treated with Cu4 O3 NPs. The current study obtained the significant antiproliferative potential of Cu4 O3 NPs against the cervical cancer cell line, which needs to be confirmed further in a suitable in vivo model. Based on our results, we also recommend the green-based, eco-friendly, and cost-effective alternative method for synthesizing novel nanoformulation.

JAM-C Is Important for Lens Epithelial Cell Proliferation and Lens Fiber Maturation in Murine Lens Development

Purpose

The underlying mechanism of congenital cataracts caused by deficiency or mutation of junctional adhesion molecule C (JAM-C) gene remains unclear. Our study aims to elucidate the abnormal developmental process in Jamc-/- lenses and reveal the genes related to lens development that JAM-C may regulate.

Methods

Jamc knockout (Jamc-/-) mouse embryos and pups were generated for in vivo studies. Four key developmental stages from embryonic day (E) 12.5 to postnatal day (P) 0.5 were selected for the following experiments. Hematoxylin and eosin staining was used for histological analysis. The 5-bromo-2'-deoxyuridine (BrdU) incorporation assay and TUNEL staining were performed to label lens epithelial cell (LEC) proliferation and apoptosis, respectively. Immunofluorescence and Western blot were used to analyze the markers of lens epithelium, cell cycle exit, and lens fiber differentiation.

Results

JAM-C was expressed throughout the process of lens development. Deletion of Jamc resulted in decreased lens size and disorganized lens fibers, which arose from E16.5 and aggravated gradually. The LECs of Jamc-/- lenses showed decreased quantity and proliferation, accompanied with reduction of key transcription factor, FOXE3. The fibers in Jamc-/- lenses were disorganized. Moreover, Jamc-deficient lens fibers showed significantly altered distribution patterns of Cx46 and Cx50. The marker of fiber homeostasis, γ-crystallin, was also decreased in the inner cortex and core fibers of Jamc-/- lenses.

Conclusions

Deletion of JAM-C exhibits malfunction of LEC proliferation and fiber maturation during murine lens development, which may be related to the downregulation of FOXE3 expression and abnormal localization patterns of Cx46 and Cx50.

Potential of green-synthesized ZnO NPs against human ovarian teratocarcinoma: an in vitro study

BACKGROUND

Ovarian cancer leads to devastating outcomes, and its treatment is highly challenging. At present, there is a lack of clinical symptoms, well-known sensitivity biomarkers, and patients are diagnosed at an advanced stage. Currently, available therapeutics against ovarian cancer are inefficient, costly, and associated with severe side effects. The present study evaluated the anticancer potential of zinc oxide nanoparticles (ZnO NPs) that were successfully biosynthesized in an ecofriendly mode using pumpkin seed extracts.

METHODS AND RESULTS

The anticancer potential of the biosynthesized ZnO NPs was assessed using an in vitro human ovarian teratocarcinoma cell line (PA-1) by well-known assays such as MTT assay, morphological alterations, induction of apoptosis, measurement of reactive oxygen species (ROS) production, and inhibition of cell adhesion/migration. The biogenic ZnO NPs exerted a high level of cytotoxicity against PA-1 cells. Furthermore, the ZnO NPs inhibited cellular adhesion and migration but induced ROS production and cell death through programmed cell death.

CONCLUSION

The aforementioned anticancer properties highlight the therapeutic utility of ZnO NPs in ovarian cancer treatment. However, further research is recommended to envisage their mechanism of action in different cancer models and validation in a suitable in vivo system.

Decreased junctional adhesion molecule 3 expression induces reactive oxygen species production and apoptosis in trophoblasts

Junctional adhesion molecule 3 (JAM3) involved in epithelial cell junction, cell polarity and motility. The molecular mechanisms underlying the role of JAM3 in placental dysfunction remain unclear. We hypothesized that JAM3 expression regulates trophoblast fusion, differentiation, proliferation, and apoptosis. Our results revealed that JAM3 was expressed in the cytotrophoblasts and syncytiotrophoblasts of first-trimester and term placental villi. JAM3 expression in cell–cell junctions decreased with the formation of syncytiotrophoblasts. Using trophoblasts as an in vitro model, we observed that forskolin and JAM3 knockdown significantly reduced JAM3 expression and increased syncytium formation. JAM3 knockdown additionally inhibited trophoblast proliferation and increased the number of trophoblasts in the sub-G1 and G2/M phases, indicating cell cycle disturbance and apoptosis. Cell cycle arrest was associated with the engagement of Checkpoint kinase 2–cell division cycle 25C–Cyclin-dependent kinase 1/Cyclin B1 signaling. Increased expression of BIM, NOXA, XAF1, cytochrome c, and cleaved caspase-3 further indicated trophoblast apoptosis. Overexpression of JAM3 or recombinant JAM3 protein enhanced trophoblast adhesion and migration, which were inhibited by JAM3 knockdown. JAM3 knockdown induced reactive oxygen species and syncytin 2 expression in trophoblasts. Furthermore, H2O2-induced oxidative stress reduced JAM3 expression in trophoblasts and cell culture supernatants. H2O2 simultaneously induced trophoblast apoptosis. JAM3 expression was significantly decreased in the plasmas and placentas of patients with early-onset severe preeclampsia. Thus, our results demonstrate that JAM3 may not only be a structural component of trophoblast cell junctions but also regulate trophoblast fusion, differentiation, proliferation, apoptosis, and motility. Dysregulated trophoblast JAM3 expression is crucial in preeclampsia development.

The Roles of Junctional Adhesion Molecules (JAMs) in Cell Migration

The review briefly summarizes the role of the family of adhesion molecules, JAMs (junctional adhesion molecules), in various cell migration, covering germ cells, epithelial cells, endothelial cells, several leukocytes, and different cancer cells. These functions affect multiple diseases, including reproductive diseases, inflammation-related diseases, cardiovascular diseases, and cancers. JAMs bind to both similar and dissimilar proteins and take both similar and dissimilar effects on different cells. Concluding relevant results provides a reference to further research.

Junctional Adhesion Molecule-C expression specifies a CD138low/neg multiple myeloma cell population in mice and humans

JAM-C identifies a distinct MM cell population in bone marrow of patients and mice.

Targeting JAM-C ameliorates MM progression and offers potential therapeutic options that might complement standard treatment regimens.

Deregulation such as overexpression of adhesion molecules influences cancer progression and survival. Metastasis of malignant cells from their primary tumor site to distant organs is the most common reason for cancer-related deaths. Junctional adhesion molecule-C (JAM-C), a member of the immunoglobulin-like JAM family, can homodimerize and aid cancer cell migration and metastasis. Here we show that this molecule is dynamically expressed on multiple myeloma (MM) cells in the bone marrow and co-localizes with blood vessels within the bone marrow of patients and mice. In addition, upregulation of JAM-C inversely correlates with the downregulation of the canonical plasma cell marker CD138 (syndecan-1), whose surface expression has recently been found to dynamically regulate a switch between MM growth in situ and MM dissemination. Moreover, targeting JAM-C in a syngeneic in vivo MM model ameliorates MM progression and improves outcome. Overall, our data demonstrate that JAM-C might serve not only as an additional novel diagnostic biomarker but also as a therapeutic target in MM disease.

Junctional Adhesion Molecule-Like Protein Promotes Tumor Progression and Metastasis via p38 Signaling Pathway in Gastric Cancer

Junctional adhesion molecule-like protein (JAML), a newly discovered junctional adhesion molecule (JAM), mediates the adhesion and migration processes of various immune cells and endothelial/epithelial cells, ultimately regulating inflammation reaction. However, its role in tumors remains to be determined. The expression of JAML was examined in gastric cancer (GC) and peritumoral tissues from 63 patients. The relationship between JAML expression and clinical characteristics was also observed. In vitro, GC cell migration and proliferation were assessed by wound healing assay, transwell migration assay and EdU incorporation assay. Immunohistochemical staining results showed that JAML expression level was higher in GC tissues than in peritumoral tissues. High expression of JAML in cancer tissues was associated with worse cell differentiation, local lymph node involvement, deep infiltration, and advanced stage. In vitro, we found that JAML silencing inhibited GC cell migration and proliferation, while JAML overexpression promoted GC cell migration and proliferation, partially via p38 signaling. Taken together, our study revealed a critical role for JAML to promote GC cell migration and proliferation. JAML might be a novel diagnostic biomarker and therapeutic target for GC.

Soluble JAM-C Ectodomain Serves as the Niche for Adipose-Derived Stromal/Stem Cells

Junctional adhesion molecules (JAMs) are expressed in diverse types of stem and progenitor cells, but their physiological significance has yet to be established. Here, we report that JAMs exhibit a novel mode of interaction and biological activity in adipose-derived stromal/stem cells (ADSCs). Among the JAM family members, JAM-B and JAM-C were concentrated along the cell membranes of mouse ADSCs. JAM-C but not JAM-B was broadly distributed in the interstitial spaces of mouse adipose tissue. Interestingly, the JAM-C ectodomain was cleaved and secreted as a soluble form (sJAM-C) in vitro and in vivo, leading to deposition in the fat interstitial tissue. When ADSCs were grown in culture plates coated with sJAM-C, cell adhesion, cell proliferation and the expression of five mesenchymal stem cell markers, Cd44, Cd105, Cd140a, Cd166 and Sca-1, were significantly elevated. Moreover, immunoprecipitation assay showed that sJAM-C formed a complex with JAM-B. Using CRISPR/Cas9-based genome editing, we also demonstrated that sJAM-C was coupled with JAM-B to stimulate ADSC adhesion and maintenance. Together, these findings provide insight into the unique function of sJAM-C in ADSCs. We propose that JAMs contribute not only to cell–cell adhesion, but also to cell–matrix adhesion, by excising their ectodomain and functioning as a niche-like microenvironment for stem and progenitor cells.

Junctional Adhesion Molecules in Cancer: A Paradigm for the Diverse Functions of Cell-Cell Interactions in Tumor Progression

Tight junction (TJ) proteins are essential for mediating interactions between adjacent cells and coordinating cellular and organ responses. Initial investigations into TJ proteins and junctional adhesion molecules (JAM) in cancer suggested a tumor-suppressive role where decreased expression led to increased metastasis. However, recent studies of the JAM family members JAM-A and JAM-C have expanded the roles of these proteins to include protumorigenic functions, including inhibition of apoptosis and promotion of proliferation, cancer stem cell biology, and epithelial-to-mesenchymal transition. JAM function by interacting with other proteins through three distinct molecular mechanisms: direct cell-cell interaction on adjacent cells, stabilization of adjacent cell surface receptors on the same cell, and interactions between JAM and cell surface receptors expressed on adjacent cells. Collectively, these diverse interactions contribute to both the pro- and antitumorigenic functions of JAM. In this review, we discuss these context-dependent functions of JAM in a variety of cancers and highlight key areas that remain poorly understood, including their potentially diverse intracellular signaling networks, their roles in the tumor microenvironment, and the consequences of posttranslational modifications on their function. These studies have implications in furthering our understanding of JAM in cancer and provide a paradigm for exploring additional roles of TJ proteins.

Relationship between apical junction proteins, gene expression and cancer

The apical junctional complex (AJC) is a cell-cell adhesion system present at the upper portion of the lateral membrane of epithelial cells integrated by the tight junction (TJ) and the adherens junction (AJ). This complex is crucial to initiate and stabilize cell-cell adhesion, to regulate the paracellular transit of ions and molecules and to maintain cell polarity. Moreover, we now consider the AJC as a hub of signal transduction that regulates cell-cell adhesion, gene transcription and cell proliferation and differentiation. The molecular components of the AJC are multiple and diverse and depending on the cellular context some of the proteins in this complex act as tumor suppressors or as promoters of cell transformation, migration and metastasis outgrowth. Here, we describe these new roles played by TJ and AJ proteins and their potential use in cancer diagnostics and as targets for therapeutic intervention.

The G Protein-Coupled Estrogen Receptor (GPER) Expression Correlates with Pro-Metastatic Pathways in ER-Negative Breast Cancer: A Bioinformatics Analysis

The G protein-coupled estrogen receptor (GPER, formerly known as GPR30) is a seven-transmembrane receptor that mediates estrogen signals in both normal and malignant cells. In particular, GPER has been involved in the activation of diverse signaling pathways toward transcriptional and biological responses that characterize the progression of breast cancer (BC). In this context, a correlation between GPER expression and worse clinical-pathological features of BC has been suggested, although controversial data have also been reported. In order to better assess the biological significance of GPER in the aggressive estrogen receptor (ER)-negative BC, we performed a bioinformatics analysis using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets. Gene expression correlation and the statistical analysis were carried out with R studio base functions and the tidyverse package. Pathway enrichment analysis was evaluated with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway on the Database for Annotation, Visualization and Integrated Discovery (DAVID) website, whereas gene set enrichment analysis (GSEA) was performed with the R package phenoTest. The survival analysis was determined with the R package survivALL. Analyzing the expression data of more than 2500 primary BC, we ascertained that GPER levels are associated with pro-migratory and metastatic genes belonging to cell adhesion molecules (CAMs), extracellular matrix (ECM)-receptor interaction, and focal adhesion (FA) signaling pathways. Thereafter, evaluating the disease-free interval (DFI) in ER-negative BC patients, we found that the subjects expressing high GPER levels exhibited a shorter DFI in respect to those exhibiting low GPER levels. Overall, our results may pave the way to further dissect the network triggered by GPER in the breast malignancies lacking ER toward a better assessment of its prognostic significance and the action elicited in mediating the aggressive features of the aforementioned BC subtype.

Junctional Adhesion Molecule-C Mediates the Recruitment of Embryonic-Endothelial Progenitor Cells to the Perivascular Niche during Tumor Angiogenesis

The homing of Endothelial Progenitor Cells (EPCs) to tumor angiogenic sites has been described as a multistep process, involving adhesion, migration, incorporation and sprouting, for which the underlying molecular and cellular mechanisms are yet to be fully defined. Here, we studied the expression of Junctional Adhesion Molecule-C (JAM-C) by EPCs and its role in EPC homing to tumor angiogenic vessels. For this, we used mouse embryonic-Endothelial Progenitor Cells (e-EPCs), intravital multi-fluorescence microscopy techniques and the dorsal skin-fold chamber model. JAM-C was found to be expressed by e-EPCs and endothelial cells. Blocking JAM-C did not affect adhesion of e-EPCs to endothelial monolayers in vitro but, interestingly, it did reduce their adhesion to tumor endothelium in vivo. The most striking effect of JAM-C blocking was on tube formation on matrigel in vitro and the incorporation and sprouting of e-EPCs to tumor endothelium in vivo. Our results demonstrate that JAM-C mediates e-EPC recruitment to tumor angiogenic sites, i.e., coordinated homing of EPCs to the perivascular niche, where they cluster and interact with tumor blood vessels. This suggests that JAM-C plays a critical role in the process of vascular assembly and may represent a potential therapeutic target to control tumor angiogenesis.