FAK-Mediated Signaling Controls Amyloid Beta Overload, Learning and Memory Deficits in a Mouse Model of Alzheimer’s Disease

The non-receptor focal adhesion kinase (FAK) is highly expressed in the central nervous system during development, where it regulates neurite outgrowth and axon guidance, but its role in the adult healthy and diseased brain, specifically in Alzheimer’s disease (AD), is largely unknown. Using the 3xTg-AD mouse model, which carries three mutations associated with familial Alzheimer’s disease (APP KM670/671NL Swedish, PSEN1 M146V, MAPT P301L) and develops age-related progressive neuropathology including amyloid plaques and Tau tangles, we describe here, for the first time, the in vivo role of FAK in AD pathology. Our data demonstrate that while site-specific knockdown in the hippocampi of 3xTg-AD mice has no effect on learning and memory, hippocampal overexpression of the protein leads to a significant decrease in learning and memory capabilities, which is accompanied by a significant increase in amyloid β (Aβ) load. Furthermore, neuronal morphology is altered following hippocampal overexpression of FAK in these mice. High-throughput proteomics analysis of total and phosphorylated proteins in the hippocampi of FAK overexpressing mice indicates that FAK controls AD-like phenotypes by inhibiting cytoskeletal remodeling in neurons which results in morphological changes, by increasing Tau hyperphosphorylation, and by blocking astrocyte differentiation. FAK activates cell cycle re-entry and consequent cell death while downregulating insulin signaling, thereby increasing insulin resistance and leading to oxidative stress. Our data provide an overview of the signaling networks by which FAK regulates AD pathology and identify FAK as a novel therapeutic target for treating AD

Expression of CXCR4 and MMP-2 is associated with poor prognosis in patients with osteosarcoma

Backgroud. Osteosarcoma is a primary malignant tumor with a high tendency to form metastasis and poor prognosis. Consequently, finding effective early indicators of metastases is crucial for identifying and treating high-risk patients. CXCR4 and MMP-2 have been found to strongly correlate with invasion and metastasis of malignant tumors, including osteosarcoma. Materials and Methods. Our study evaluated CXCR4 in conjunction with MMP-2 as an important clinicopathological prognostic predictor for metastasis and overall survival of osteosarcoma. 73 patients’ clinical data and pathological samples were retrieved for the study. A median time of 36 months follow-up was performed to evaluate for tumor metastasis and patient survival. CXCR4 and MMP-2 proteins in tumor tissues were detected by immunohistochemistry on paraffin- embedded tissue sections. Results. The positive expression rate of CXCR4 and MMP-2 was 68.5% and 54.8% respectively, and of the 45 patients who developed distal metastasis, 33 and 28 patients had positive expression of CXCR4 and MMP-2 respectively. The median metastasis-free survival was 72.00 months in the CXCR4-negative group and 14.00 months in the CXCR4 positive group. Furthermore, median overall survival was 73.77 and 24.00 months in these same two groups. Further, the median metastasis-free survival was 66.51 months in the MMP-2 negative group and 9.00 months in the MMP-2 positive group. The median overall survival was 75.07 and 19.00 months in these same two groups. MMP2 and metastasis remained the significant and independent prognostic factors for metastasis-free survival and overall survival by using the COX regression model adjusted for the multivariate predictors of survival. Conclusion. Our results suggest that metastasis and MMP-2 are both independent prognostic indicators for metastasis-free and overall survival of osteosarcoma patients

Antibody-drug conjugate αEGFR-E-P125A reduces triple-negative breast cancer vasculogenic mimicry, motility, and metastasis through inhibition of EGFR, integrin, and FAK/STAT3 signaling

Primary tumor growth and metastasis in triple-negative breast cancer (TNBC) require supporting vasculature, which develop through a combination of endothelial angiogenesis and vasculogenic mimicry (VM), a process associated with aggressive metastatic behavior in which vascular-like structures are lined by tumor cells. We developed αEGFR-E-P125A, an antibody-endostatin fusion protein that delivers a dimeric, mutant endostatin (E-P125A) payload that inhibits TNBC angiogenesis and VM in vitro and in vivo. To characterize the mechanisms associated with induction and inhibition of VM, RNA-seq of MDA-MB-231-4175 TNBC cells grown in a monolayer (2D) was compared to cells plated on Matrigel undergoing VM (3D). We then compared RNA-seq between TNBC cells in 3D and cells in 3D with VM inhibited by αEGFR-E-P125A (EGFR-E-P125A). Gene set enrichment analysis (GSEA) demonstrated that VM induction activated the IL6-JAK-STAT3 and angiogenesis pathways, which were downregulated by αEGFR-E-P125A treatment. Correlative analysis of the phospho-proteome demonstrated decreased EGFR phosphorylation at Y1069, along with decreased phosphorylation of focal adhesion kinase (FAK) Y397 and STAT3 Y705 sites downstream of α5β1 integrin. Suppression of phosphorylation events downstream of EGFR and α5β1 integrin demonstrated that αEGFR-E-P125A interferes with ligand-receptor activation, inhibits VM, and overcomes oncogenic signaling associated with EGFR and α5β1 integrin crosstalk. In vivo, αEGFR-E-P125A treatment decreased primary tumor growth and VM, reduced lung metastasis, and confirmed the inhibition of signaling events observed in vitro. Simultaneous inhibition of EGFR and α5β1 integrin signaling by αEGFR-E-P125A is a promising strategy for the inhibition of VM, tumor growth, motility, and metastasis in TNBC and other EGFR-overexpressing tumors

Feedback between mechanosensitive signaling and active forces governs endothelial junction integrity

The formation and recovery of gaps in the vascular endothelium governs a wide range of physiological and pathological phenomena, from angiogenesis to tumor cell extravasation. However, the interplay between the mechanical and signaling processes that drive dynamic behavior in vascular endothelial cells is not well understood. In this study, we propose a chemo-mechanical model to investigate the regulation of endothelial junctions as dependent on the feedback between actomyosin contractility, VE-cadherin bond turnover, and actin polymerization, which mediate the forces exerted on the cell-cell interface. Simulations reveal that active cell tension can stabilize cadherin bonds, but excessive RhoA signaling can drive bond dissociation and junction failure. While actin polymerization aids gap closure, high levels of Rac1 can induce junction weakening. Combining the modeling framework with experiments, our model predicts the influence of pharmacological treatments on the junction state and identifies that a critical balance between RhoA and Rac1 expression is required to maintain junction stability. Our proposed framework can help guide the development of therapeutics that target the Rho family of GTPases and downstream active mechanical processes