Senescent CAFs Mediate Immunosuppression and Drive Breast Cancer Progression.

The tumor microenvironment (TME) profoundly influences tumorigenesis, with gene expression in the breast TME capable of predicting clinical outcomes. The TME is complex and includes distinct cancer-associated fibroblast (CAF) subtypes whose contribution to tumorigenesis remains unclear. Here, we identify a subset of myofibroblast CAFs (myCAF) that are senescent (senCAF) in mouse and human breast tumors.

ROR2/Wnt5a Signaling Regulates Directional Cell Migration and Early Tumor Cell Invasion in Ovarian Cancer.

Unlabelled: Adhesion to and clearance of the mesothelial monolayer are key early events in metastatic seeding of ovarian cancer. ROR2 is a receptor tyrosine kinase that interacts with Wnt5a ligand to activate noncanonical Wnt signaling and has been previously shown to be upregulated in ovarian cancer tissue. However, no prior study has evaluated the mechanistic role of ROR2 in ovarian cancer.

Functional analysis of recurrent CDC20 promoter variants in human melanoma.

Small nucleotide variants in non-coding regions of the genome can alter transcriptional regulation, leading to changes in gene expression which can activate oncogenic gene regulatory networks. Melanoma is heavily burdened by non-coding variants, representing over 99% of total genetic variation, including the well-characterized TERT promoter mutation. However, the compendium of regulatory non-coding variants is likely still functionally under-characterized.

A Cdh3-β-catenin-laminin signaling axis in a subset of breast tumor leader cells control leader cell polarization and directional collective migration.

Carcinoma dissemination can occur when heterogeneous tumor and tumor-stromal cell clusters migrate together via collective migration. Cells at the front lead and direct collective migration, yet how these leader cells form and direct migration are not fully appreciated. From live videos of primary mouse and human breast tumor organoids in a 3D microfluidic system mimicking native breast tumor microenvironment, we developed 3D computational models, which hypothesize that leader cells need to generate high protrusive forces and overcome extracellular matrix (ECM) resistance at the leading edge.

β-Integrin Adhesive Bond Tension under Shear Stress Modulates Cytosolic Calcium Flux and Neutrophil Inflammatory Response.

On arrested neutrophils a focal adhesive cluster of ~200 high affinity (HA) β-integrin bonds under tension is sufficient to trigger Ca flux that signals an increase in activation in direct proportion to increments in shear stress. We reasoned that a threshold tension acting on individual β-integrin bonds provides a mechanical means of transducing the magnitude of fluid drag force into signals that enhance the efficiency of neutrophil recruitment and effector function. Tension gauge tethers (TGT) are a duplex of DNA nucleotides that rupture at a precise shear force, which increases with the extent of nucleotide overlap, ranging from a tolerance of 54pN to 12pN.

Tyrosine kinase-independent actions of DDR2 in tumor cells and cancer-associated fibroblasts influence tumor invasion, migration and metastasis.

Both tumor cell-intrinsic signals and tumor cell-extrinsic signals from cells within the tumor microenvironment influence tumor cell dissemination and metastasis. The fibrillar collagen receptor tyrosine kinase (RTK) discoidin domain receptor 2 (DDR2) is essential for breast cancer metastasis in mouse models, and high expression of DDR2 in tumor and tumor stromal cells is strongly associated with poorer clinical outcomes. DDR2 tyrosine kinase activity has been hypothesized to be required for the metastatic activity of DDR2; however, inhibition of DDR2 tyrosine kinase activity, along with that of other RTKs, has failed to provide clinically relevant responses in metastatic patients.

Targeting Neutrophil Adhesive Events to Address Vaso-Occlusive Crisis in Sickle Cell Patients.

Neutrophils are essential to protect the host against invading pathogens but can promote disease progression in sickle cell disease (SCD) by becoming adherent to inflamed microvascular networks in peripheral tissue throughout the body. During the inflammatory response, leukocytes extravasate from the bloodstream using selectin adhesion molecules and migrate to sites of tissue insult through activation of integrins that are essential for combating pathogens. However, during vaso-occlusion associated with SCD, neutrophils are activated during tethering and rolling on selectins upregulated on activated endothelium that line blood vessels.

The voltage-gated potassium channel KV1.3 regulates neutrophil recruitment during inflammation.

Aims: Neutrophil trafficking within the vasculature strongly relies on intracellular calcium signalling. Sustained Ca2+ influx into the cell requires a compensatory efflux of potassium to maintain membrane potential. Here, we aimed to investigate whether the voltage-gated potassium channel KV1.

Neutrophil Inflammatory Response Is Downregulated by Uptake of Superparamagnetic Iron Oxide Nanoparticle Therapeutics.

Superparamagnetic iron oxide nanoparticles (SPION) are employed as diagnostics and therapeutics following intravenous delivery for the treatment of iron deficiency anemia (IDA) in adult patients with chronic kidney failure. Neutrophils are the first defense against blood borne foreign insult and recruit to vascular sites of inflammation a sequential process that is characterized by adhesive capture, rolling, and shear resistant arrest. A primary chemotactic agonist presented on the glycocalyx of inflamed endothelium is IL-8, which upon binding to its cognate membrane receptor (CXCR1/2) activates a suite of responses in neutrophils.

Tensile force transmitted through LFA-1 bonds mechanoregulate neutrophil inflammatory response.

Recruitment of leukocytes to sites of acute inflammation is guided by spatial and temporal cues that ensure appropriate cell numbers infiltrate the tissue at precise locations to protect it from infection and initiate repair. On inflamed endothelium, neutrophil rolling via selectins elicits cytosolic calcium release from endoplasmic reticulum (ER)-stores that are synergistic with chemokine signaling to activate formation of high affinity (HA) LFA-1 bonds to ICAM-1, which is necessary to anchor cells against the drag force of blood flow. Bond tension on LFA-1 within the area of adhesive contact with endothelium elicits calcium entry through calcium release-activated calcium channel protein 1 (Orai-1) membrane channels that in turn activate neutrophil shape change and migration.

Kinky integrins reveal a new wrinkle in neutrophil activation.

Discussion on the flexible kink produced in the β -integrin transmembrane domain blocking mechanotransduction of signals necessary for neutrophil arrest and spreading.

Selectin-Targeting Peptide-Glycosaminoglycan Conjugates Modulate Neutrophil-Endothelial Interactions.

Introduction: The glycocalyx is a layer of glycoproteins, proteoglycans and glycosaminoglycans that coats the luminal surface of most blood vessels. It effectively regulates adhesive interactions between leukocytes in flowing blood and the endothelium, where during inflammation, binding to E- and P-selectins and intercellular adhesion molecule-1 (ICAM-1) promotes cell tethering and arrest under shear flow.

Methods: In this study, we examine the targeting of E-selectin by an engineered peptide moiety bound to a dermatan sulfate backbone.

Neutrophil Mechanosignaling Promotes Integrin Engagement With Endothelial Cells and Motility Within Inflamed Vessels.

Neutrophils are the most motile of mammalian cells, a feature that enables them to protect the host against the rapid spread of pathogens from tissue into the circulatory system. A critical process is the recruitment of neutrophils to inflamed endothelium within post-capillary venules. This occurs through cooperation between at least four families of adhesion molecules and G-protein coupled signaling receptors.

Virtual Screening of Chemical Compounds for Discovery of Complement C3 Ligands.

The complement system is our first line of defense against foreign pathogens, but when it is not properly regulated, complement is implicated in the pathology of several autoimmune and inflammatory disorders. Compstatin is a peptidic complement inhibitor that acts by blocking the cleavage of complement protein C3 to the proinflammatory fragment C3a and opsonin fragment C3b. In this study, we aim to identify druglike small-molecule complement inhibitors with physicochemical, geometric, and binding properties similar to those of compstatin.

CagY-Dependent Regulation of Type IV Secretion in Helicobacter pylori Is Associated with Alterations in Integrin Binding.

Strains of that cause ulcer or gastric cancer typically express a type IV secretion system (T4SS) encoded by the pathogenicity island (PAI). CagY is an ortholog of VirB10 that, unlike other VirB10 orthologs, has a large middle repeat region (MRR) with extensive repetitive sequence motifs, which undergo CD4 T cell-dependent recombination during infection of mice. Recombination in the CagY MRR reduces T4SS function, diminishes the host inflammatory response, and enables the bacteria to colonize at a higher density.

Selectin catch-bonds mechanotransduce integrin activation and neutrophil arrest on inflamed endothelium under shear flow.

E-selectin extends from the plasma membrane of inflamed endothelium and serves to capture leukocytes from flowing blood via long-lived catch-bonds that support slow leukocyte rolling under shear stress. Its ligands are glycosylated with the tetrasaccharide sialyl Lewis (sLe), which contributes to bond affinity and specificity. E-selectin-mediated rolling transmits signals into neutrophils that trigger activation of high-affinity β-integrins necessary for transition to shear-resistant adhesion and transendothelial migration.

Atrial natriuretic peptide down-regulates neutrophil recruitment on inflamed endothelium by reducing cell deformability and resistance to detachment force.

Background: Recombinant atrial natriuretic peptide (ANP) is administered in patients with acute heart failure in Japan to improve renal function and hemodynamics, but its anti-inflammatory effect on activated leukocytes may also contribute to its therapeutic efficacy.

Objective: Examine unconventional role of ANP in neutrophil adhesion to inflamed endothelium.

Methods: Human neutrophils were perfused over endothelial monolayers in a microfluidic lab-chip assay.

Glycopeptide analogues of PSGL-1 inhibit P-selectin in vitro and in vivo.

Blockade of P-selectin (P-sel)/PSGL-1 interactions holds significant potential for treatment of disorders of innate immunity, thrombosis and cancer. Current inhibitors remain limited due to low binding affinity or by the recognized disadvantages inherent to chronic administration of antibody therapeutics. Here we report an efficient approach for generating glycosulfopeptide mimics of N-terminal PSGL-1 through development of a stereoselective route for multi-gram scale synthesis of the C2 O-glycan building block and replacement of hydrolytically labile tyrosine sulfates with isosteric sulfonate analogues.

Separating instability from aggregation propensity in γS-crystallin variants.

Molecular dynamics (MD) simulations, circular dichroism (CD), and dynamic light scattering (DLS) measurements were used to investigate the aggregation propensity of the eye-lens protein γS-crystallin. The wild-type protein was investigated along with the cataract-related G18V variant and the symmetry-related G106V variant. The MD simulations suggest that local sequence differences result in dramatic differences in dynamics and hydration between these two apparently similar point mutations.