Publications by authors named "David D Schlaepfer"

74 Publications

Endothelial angiogenic activity and adipose angiogenesis is controlled by extracellular matrix protein TGFBI.

Sci Rep 2021 05 6;11(1):9644. Epub 2021 May 6.

Department of Food Science and Biotechnology, Kyungpook National University, Daegu, 41566, Republic of Korea.

Several studies have suggested that extracellular matrix (ECM) remodeling and the microenvironment are tightly associated with adipogenesis and adipose angiogenesis. In the present study, we demonstrated that transforming growth factor-beta induced (TGFBI) suppresses angiogenesis stimulated by adipocyte-conditioned medium (Ad-CM), both in vitro and in vivo. TGFBI knockout (KO) mice exhibited increased numbers of blood vessels in adipose tissue, and blood vessels from these mice showed enhanced infiltration into Matrigel containing Ad-CM. The treatment of Ad-CM-stimulated SVEC-10 endothelial cells with TGFBI protein reduced migration and tube-forming activity. TGFBI protein suppressed the activation of the Src and extracellular signaling-related kinase signaling pathways of these SVEC-10 endothelial cells. Our findings indicated that TGFBI inhibited adipose angiogenesis by suppressing the activation of Src and ERK signaling pathways, possibly because of the stimulation of the angiogenic activity of endothelial cells.
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http://dx.doi.org/10.1038/s41598-021-88959-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102489PMC
May 2021

Force-FAK signaling coupling at individual focal adhesions coordinates mechanosensing and microtissue repair.

Nat Commun 2021 04 21;12(1):2359. Epub 2021 Apr 21.

Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.

How adhesive forces are transduced and integrated into biochemical signals at focal adhesions (FAs) is poorly understood. Using cells adhering to deformable micropillar arrays, we demonstrate that traction force and FAK localization as well as traction force and Y397-FAK phosphorylation are linearly coupled at individual FAs on stiff, but not soft, substrates. Similarly, FAK phosphorylation increases linearly with external forces applied to FAs using magnetic beads. This mechanosignaling coupling requires actomyosin contractility, talin-FAK binding, and full-length vinculin that binds talin and actin. Using an in vitro 3D biomimetic wound healing model, we show that force-FAK signaling coupling coordinates cell migration and tissue-scale forces to promote microtissue repair. A simple kinetic binding model of talin-FAK interactions under force can recapitulate the experimental observations. This study provides insights on how talin and vinculin convert forces into FAK signaling events regulating cell migration and tissue repair.
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http://dx.doi.org/10.1038/s41467-021-22602-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8060400PMC
April 2021

Targeting FAK in anticancer combination therapies.

Nat Rev Cancer 2021 05 17;21(5):313-324. Epub 2021 Mar 17.

Cancer Research UK Edinburgh Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.

Focal adhesion kinase (FAK) is both a non-receptor tyrosine kinase and an adaptor protein that primarily regulates adhesion signalling and cell migration, but FAK can also promote cell survival in response to stress. FAK is commonly overexpressed in cancer and is considered a high-value druggable target, with multiple FAK inhibitors currently in development. Evidence suggests that in the clinical setting, FAK targeting will be most effective in combination with other agents so as to reverse failure of chemotherapies or targeted therapies and enhance efficacy of immune-based treatments of solid tumours. Here, we discuss the recent preclinical evidence that implicates FAK in anticancer therapeutic resistance, leading to the view that FAK inhibitors will have their greatest utility as combination therapies in selected patient populations.
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http://dx.doi.org/10.1038/s41568-021-00340-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8276817PMC
May 2021

Autophagy gene haploinsufficiency drives chromosome instability, increases migration, and promotes early ovarian tumors.

PLoS Genet 2020 01 10;16(1):e1008558. Epub 2020 Jan 10.

UC San Diego Moores Cancer Center, La Jolla, California, United States of America.

Autophagy, particularly with BECN1, has paradoxically been highlighted as tumor promoting in Ras-driven cancers, but potentially tumor suppressing in breast and ovarian cancers. However, studying the specific role of BECN1 at the genetic level is complicated due to its genomic proximity to BRCA1 on both human (chromosome 17) and murine (chromosome 11) genomes. In human breast and ovarian cancers, the monoallelic deletion of these genes is often co-occurring. To investigate the potential tumor suppressor roles of two of the most commonly deleted autophagy genes in ovarian cancer, BECN1 and MAP1LC3B were knocked-down in atypical (BECN1+/+ and MAP1LC3B+/+) ovarian cancer cells. Ultra-performance liquid chromatography mass-spectrometry metabolomics revealed reduced levels of acetyl-CoA which corresponded with elevated levels of glycerophospholipids and sphingolipids. Migration rates of ovarian cancer cells were increased upon autophagy gene knockdown. Genomic instability was increased, resulting in copy-number alteration patterns which mimicked high grade serous ovarian cancer. We further investigated the causal role of Becn1 haploinsufficiency for oncogenesis in a MISIIR SV40 large T antigen driven spontaneous ovarian cancer mouse model. Tumors were evident earlier among the Becn1+/- mice, and this correlated with an increase in copy-number alterations per chromosome in the Becn1+/- tumors. The results support monoallelic loss of BECN1 as permissive for tumor initiation and potentiating for genomic instability in ovarian cancer.
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http://dx.doi.org/10.1371/journal.pgen.1008558DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6953790PMC
January 2020

FAK activity sustains intrinsic and acquired ovarian cancer resistance to platinum chemotherapy.

Elife 2019 09 3;8. Epub 2019 Sep 3.

Department of Obstetrics, Gynecology and Reproductive Sciences, Moores UCSD Cancer Center, La Jolla, United States.

Gene copy number alterations, tumor cell stemness, and the development of platinum chemotherapy resistance contribute to high-grade serous ovarian cancer (HGSOC) recurrence. Stem phenotypes involving Wnt-β-catenin, aldehyde dehydrogenase activities, intrinsic platinum resistance, and tumorsphere formation are here associated with spontaneous gains in , and (KMF) genes in a new aggressive murine model of ovarian cancer. Adhesion-independent FAK signaling sustained KMF and human tumorsphere proliferation as well as resistance to cisplatin cytotoxicity. Platinum-resistant tumorspheres can acquire a dependence on FAK for growth. Accordingly, increased FAK tyrosine phosphorylation was observed within HGSOC patient tumors surviving neo-adjuvant chemotherapy. Combining a FAK inhibitor with platinum overcame chemoresistance and triggered cell apoptosis. FAK transcriptomic analyses across knockout and reconstituted cells identified 135 targets, elevated in HGSOC, that were regulated by FAK activity and β-catenin including Myc, pluripotency and DNA repair genes. These studies reveal an oncogenic FAK signaling role supporting chemoresistance.
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http://dx.doi.org/10.7554/eLife.47327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6721800PMC
September 2019

Rgnef promotes ovarian tumor progression and confers protection from oxidative stress.

Oncogene 2019 09 15;38(36):6323-6337. Epub 2019 Jul 15.

Moores Cancer Center, Department of Obstetrics, Gynecology and Reproductive Science, UC San Diego Health, La Jolla, CA, 92093, USA.

Ovarian cancer is the fifth-leading cause of cancer death among women. The dissemination of ovarian tumors and growth as spheroids accompanies late-stage disease. In cell culture, ovarian tumor cell spheroids can exhibit elevated resistance to environmental stressors, such as reactive oxygen species. Homeostatic balance of the antioxidant response is a protective mechanism that prevents anoikis, a form of programmed cell death. Signaling pathways activated by integrin receptors suppress anoikis. Rgnef (ARHGEF28/p190RhoGEF) is a guanine nucleotide exchange factor that is activated downstream of integrins. We find that Rgnef protein levels are elevated in late-stage serous ovarian cancer, high Rgnef mRNA levels are associated with decreased progression-free and overall survival, and genomic ARHGEF28 loss is associated with increased patient survival. Using transgenic and transplantable Rgnef knockout mouse models, we find that Rgnef is essential for supporting three-dimensional ovarian spheroid formation in vitro and tumor growth in mice. Using RNA-sequencing and bioinformatic analyses, we identify a conserved Rgnef-supported anti-oxidant gene signature including Gpx4, Nqo1, and Gsta4; common targets of the NF-kB transcription factor. Antioxidant treatment enhanced growth of Rgnef-knockout spheroids and Rgnef re-expression facilitated NF-κB-dependent tumorsphere survival. These studies reveal a new role for Rgnef in ovarian cancer to facilitate NF-κB-mediated gene expression protecting cells from oxidative stress.
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http://dx.doi.org/10.1038/s41388-019-0881-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7252434PMC
September 2019

Nuclear Focal Adhesion Kinase Controls Vascular Smooth Muscle Cell Proliferation and Neointimal Hyperplasia Through GATA4-Mediated Cyclin D1 Transcription.

Circ Res 2019 07 17;125(2):152-166. Epub 2019 May 17.

From the Department of Biochemistry and Molecular Biology (K.J., J.M.M., H.P., S.-J.K., Y.A.R.R., W.T.G., J.-S.K., E.-Y.E.A., S.-T.S.L.), University of South Alabama, College of Medicine, Mobile.

Rationale: Neointimal hyperplasia is characterized by excessive accumulation of vascular smooth muscle cells (SMCs) leading to occlusive disorders, such as atherosclerosis and stenosis. Blood vessel injury increases growth factor secretion and matrix synthesis, which promotes SMC proliferation and neointimal hyperplasia via FAK (focal adhesion kinase).

Objective: To understand the mechanism of FAK action in SMC proliferation and neointimal hyperplasia.

Methods And Results: Using combined pharmacological FAK catalytic inhibition (VS-4718) and SMC-specific FAK kinase-dead (Myh11-Cre-ER) mouse models, we report that FAK regulates SMC proliferation and neointimal hyperplasia in part by governing GATA4- (GATA-binding protein 4) cyclin D1 signaling. Inhibition of FAK catalytic activity facilitates FAK nuclear localization, which is required for proteasome-mediated GATA4 degradation in the cytoplasm. Chromatin immunoprecipitation identified GATA4 binding to the mouse cyclin D1 promoter, and loss of GATA4-mediated cyclin D1 transcription diminished SMC proliferation. Stimulation with platelet-derived growth factor or serum activated FAK and redistributed FAK from the nucleus to cytoplasm, leading to concomitant increase in GATA4 protein and cyclin D1 expression. In a femoral artery wire injury model, increased neointimal hyperplasia was observed in parallel with elevated FAK activity, GATA4 and cyclin D1 expression following injury in control mice, but not in VS-4718-treated and SMC-specific FAK kinase-dead mice. Finally, lentiviral shGATA4 knockdown in the wire injury significantly reduced cyclin D1 expression, SMC proliferation, and neointimal hyperplasia compared with control mice.

Conclusions: Nuclear enrichment of FAK by inhibition of FAK catalytic activity during vessel injury blocks SMC proliferation and neointimal hyperplasia through regulation of GATA4-mediated cyclin D1 transcription.
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http://dx.doi.org/10.1161/CIRCRESAHA.118.314344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6702425PMC
July 2019

A Platform of Synthetic Lethal Gene Interaction Networks Reveals that the GNAQ Uveal Melanoma Oncogene Controls the Hippo Pathway through FAK.

Cancer Cell 2019 03 14;35(3):457-472.e5. Epub 2019 Feb 14.

Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA. Electronic address:

Activating mutations in GNAQ/GNA11, encoding Gαq G proteins, are initiating oncogenic events in uveal melanoma (UM). However, there are no effective therapies for UM. Using an integrated bioinformatics pipeline, we found that PTK2, encoding focal adhesion kinase (FAK), represents a candidate synthetic lethal gene with GNAQ activation. We show that Gαq activates FAK through TRIO-RhoA non-canonical Gαq-signaling, and genetic ablation or pharmacological inhibition of FAK inhibits UM growth. Analysis of the FAK-regulated transcriptome demonstrated that GNAQ stimulates YAP through FAK. Dissection of the underlying mechanism revealed that FAK regulates YAP by tyrosine phosphorylation of MOB1, inhibiting core Hippo signaling. Our findings establish FAK as a potential therapeutic target for UM and other Gαq-driven pathophysiologies that involve unrestrained YAP function.
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http://dx.doi.org/10.1016/j.ccell.2019.01.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6737937PMC
March 2019

Adaptive Resistance to Chemotherapy, A Multi-FAK-torial Linkage.

Mol Cancer Ther 2018 04;17(4):719-723

Department of Reproductive Medicine, University of California, San Diego, School of Medicine, Moores Cancer Center, La Jolla, California.

Oncogenes provide tumor cells with a growth and survival advantage. Directed therapies targeted to oncogenic mutations (such as V600E) are part of effective late-stage melanoma treatment. However, tumors with V600E mutations, in approximately 10% of colorectal cancer, are generally treatment-insensitive. Research has identified various "feedback" mechanisms that result in BRAF signal pathway reactivation in response to BRAF inhibition. Herein, we highlight key findings from Chen and colleagues (this issue) showing that integrin-associated focal adhesion kinase (FAK) activation selectively occurs in V600E-mutant colorectal cancer cells in response to pharmacological BRAF inhibition. FAK activation results in elevated β-catenin protein levels, β-catenin nuclear localization, and increased gene transcription. Small-molecule inhibitors of β-catenin or FAK synergize with vemurafenib BRAF inhibitor to prevent V600E colorectal cancer cell proliferation and xenograft tumor growth in mice. This study complements findings linking FAK to β-catenin in intestinal tumorigenesis, resistance to radiotherapy, and cancer stem cell survival. Thus, FAK activation may occur as a frequent tumor cell "adaptive resistance" mechanism. Although FAK () is not mutated in most cancers, targeting FAK activity in combinational approaches may limit tumor cell escape mechanisms and enhance durable responses to treatment. .
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http://dx.doi.org/10.1158/1535-7163.MCT-17-1177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6538033PMC
April 2018

Focal adhesion kinase signaling in unexpected places.

Curr Opin Cell Biol 2017 04 16;45:24-30. Epub 2017 Feb 16.

Biomedical Sciences Graduate Program, University of California, San Diego, CA, United States; Moores Cancer Center, Department of Reproductive Medicine, 3855 Health Sciences Drive, MC 0983, La Jolla, CA 92093-0983, United States. Electronic address:

Focal adhesion kinase (FAK) is a cytoplasmic protein-tyrosine kinase first identified at extracellular matrix and integrin receptor cell adhesion sites and is a key regulator of cell movement. FAK is activated by a variety of stimuli. Herein, we discuss advances in conformational-associated FAK activation and dimerization mechanisms. Additionally, new roles have emerged for FAK signaling at cell adhesions, adherens junctions, endosomes, and the nucleus. In light of these new findings, we review how FAK activation at these sites is connected to the regulation of integrin recycling-activation, vascular permeability, cell survival, and transcriptional regulation, respectively. Studies uncovering FAK signaling connections in unexpected places within cells have yielded important new regulatory insights in cell biology.
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http://dx.doi.org/10.1016/j.ceb.2017.01.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482783PMC
April 2017

Haploinsufficiency networks identify targetable patterns of allelic deficiency in low mutation ovarian cancer.

Nat Commun 2017 02 15;8:14423. Epub 2017 Feb 15.

Division of Gynecologic Oncology, Department of Reproductive Medicine, UCSD School of Medicine and UCSD Moores Cancer Center, 3855 Health Sciences Drive, La Jolla, California 39216, USA.

Identification of specific oncogenic gene changes has enabled the modern generation of targeted cancer therapeutics. In high-grade serous ovarian cancer (OV), the bulk of genetic changes is not somatic point mutations, but rather somatic copy-number alterations (SCNAs). The impact of SCNAs on tumour biology remains poorly understood. Here we build haploinsufficiency network analyses to identify which SCNA patterns are most disruptive in OV. Of all KEGG pathways (N=187), autophagy is the most significantly disrupted by coincident gene deletions. Compared with 20 other cancer types, OV is most severely disrupted in autophagy and in compensatory proteostasis pathways. Network analysis prioritizes MAP1LC3B (LC3) and BECN1 as most impactful. Knockdown of LC3 and BECN1 expression confers sensitivity to cells undergoing autophagic stress independent of platinum resistance status. The results support the use of pathway network tools to evaluate how the copy-number landscape of a tumour may guide therapy.
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http://dx.doi.org/10.1038/ncomms14423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5316854PMC
February 2017

Genotype tunes pancreatic ductal adenocarcinoma tissue tension to induce matricellular fibrosis and tumor progression.

Nat Med 2016 05 18;22(5):497-505. Epub 2016 Apr 18.

Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, California, USA.

Fibrosis compromises pancreatic ductal carcinoma (PDAC) treatment and contributes to patient mortality, yet antistromal therapies are controversial. We found that human PDACs with impaired epithelial transforming growth factor-β (TGF-β) signaling have high epithelial STAT3 activity and develop stiff, matricellular-enriched fibrosis associated with high epithelial tension and shorter patient survival. In several KRAS-driven mouse models, both the loss of TGF-β signaling and elevated β1-integrin mechanosignaling engaged a positive feedback loop whereby STAT3 signaling promotes tumor progression by increasing matricellular fibrosis and tissue tension. In contrast, epithelial STAT3 ablation attenuated tumor progression by reducing the stromal stiffening and epithelial contractility induced by loss of TGF-β signaling. In PDAC patient biopsies, higher matricellular protein and activated STAT3 were associated with SMAD4 mutation and shorter survival. The findings implicate epithelial tension and matricellular fibrosis in the aggressiveness of SMAD4 mutant pancreatic tumors and highlight STAT3 and mechanics as key drivers of this phenotype.
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http://dx.doi.org/10.1038/nm.4082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4860133PMC
May 2016

Oxidized LDL induces FAK-dependent RSK signaling to drive NF-κB activation and VCAM-1 expression.

J Cell Sci 2016 Apr 18;129(8):1580-91. Epub 2016 Feb 18.

Department of Pathology and Translational Pathobiology, LSU Health Sciences Center, Shreveport, LA 71130, USA Department of Cell Biology and Anatomy, LSU Health Sciences Center, Shreveport, LA 71130, USA

Oxidized low-density lipoprotein (oxLDL) accumulates early in atherosclerosis and promotes endothelial nuclear factor κB (NF-κB) activation, proinflammatory gene expression and monocyte adhesion. Like for other atherogenic factors, oxLDL-induced proinflammatory responses requires integrin-dependent focal adhesion kinase (FAK, also known as PTK2) signaling; however, the mechanism by which FAK mediates oxLDL-dependent NF-κB signaling has yet to be revealed. We now show that oxLDL induces NF-κB activation and VCAM-1 expression through FAK-dependent IκB kinase β (IKKβ, also known as IKBKB) activation. We further identify FAK-dependent activation of p90 ribosomal S6 kinase family proteins (RSK) as a crucial mediator of oxLDL-dependent IKKβ and NF-κB signaling, as inhibiting RSK blocks oxLDL-induced IKKβ and NF-κB activation, VCAM-1 expression and monocyte adhesion. Finally, transgenic mice containing a kinase-dead mutation in FAK specifically in the endothelial cells show reduced RSK activity, decreased VCAM-1 expression and reduced macrophage accumulation in regions of early atherosclerosis. Taken together, our data elucidates a new mechanism whereby oxLDL-induced endothelial FAK signaling drives an ERK-RSK pathway to activate IKKβ and NF-κB signaling and proinflammatory gene expression.
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http://dx.doi.org/10.1242/jcs.182097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4852771PMC
April 2016

A strategy to combine pathway-targeted low toxicity drugs in ovarian cancer.

Oncotarget 2015 Oct;6(31):31104-18

Department of Reproductive Medicine, UCSD Moores Cancer Center, La Jolla, CA, USA.

Serous Ovarian Cancers (SOC) are frequently resistant to programmed cell death. However, here we describe that these programmed death-resistant cells are nonetheless sensitive to agents that modulate autophagy. Cytotoxicity is not dependent upon apoptosis, necroptosis, or autophagy resolution. A screen of NCBI yielded more than one dozen FDA-approved agents displaying perturbed autophagy in ovarian cancer. The effects were maximized via combinatorial use of the agents that impinged upon distinct points of autophagy regulation. Autophagosome formation correlated with efficacy in vitro and the most cytotoxic two agents gave similar effects to a pentadrug combination that impinged upon five distinct modulators of autophagy. However, in a complex in vivo SOC system, the pentadrug combination outperformed the best two, leaving trace or no disease and with no evidence of systemic toxicity. Targeting the autophagy pathway in a multi-modal fashion might therefore offer a clinical option for treating recalcitrant SOC.
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http://dx.doi.org/10.18632/oncotarget.5093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4741591PMC
October 2015

FAK/PYK2 promotes the Wnt/β-catenin pathway and intestinal tumorigenesis by phosphorylating GSK3β.

Elife 2015 Sep 3;4. Epub 2015 Sep 3.

Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States.

Aberrant activation of Wnt/β-catenin signaling plays an unequivocal role in colorectal cancer, but identification of effective Wnt inhibitors for use in cancer remains a tremendous challenge. New insights into the regulation of this pathway could reveal new therapeutic point of intervention, therefore are greatly needed. Here we report a novel FAK/PYK2/GSK3β(Y216)/β-catenin regulation axis: FAK and PYK2, elevated in adenomas in APC(min/+) mice and in human colorectal cancer tissues, functioned redundantly to promote the Wnt/β-catenin pathway by phosphorylating GSK3β(Y216) to reinforce pathway output-β-catenin accumulation and intestinal tumorigenesis. We previously showed that Wnt-induced β-catenin accumulation requires Wnt-induced GSK3β/β-TrCP interaction; the current study revealed that phosphorylation of GSK3β(Y216) was a molecular determinant of GSK3β recruitment of β-TrCP. Pharmacological inhibition of FAK/PYK2 suppressed adenoma formation in APC(min/+) mice accompanied with reduced intestinal levels of phospho-GSK3β(Y216) and β-catenin, indicating that FAK/PYK2/GSK3β(Y216) axis is critical for the activation of Wnt/β-catenin signaling in APC driven intestinal tumorigenesis.
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http://dx.doi.org/10.7554/eLife.10072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4558782PMC
September 2015

Integrin α4 Enhances Metastasis and May Be Associated with Poor Prognosis in MYCN-low Neuroblastoma.

PLoS One 2015 14;10(5):e0120815. Epub 2015 May 14.

Division of Gynecologic Oncology, Department of Reproductive Medicine, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, California, 92093, United States of America; University of California San Diego Moores Cancer Center, 3855 Health Sciences Drive, La Jolla, California, 92093, United States of America.

High-risk neuroblastoma is associated with an overall survival rate of 30-50%. Neuroblastoma-expressed cell adhesion receptors of the integrin family impact cell adhesion, migration, proliferation and survival. Integrin α4 is essential for neural crest cell motility during development, is highly expressed on leukocytes, and is critical for transendothelial migration. Thus, cancer cells that express this receptor may exhibit increased metastatic potential. We show that α4 expression in human and murine neuroblastoma cell lines selectively enhances in vitro interaction with the alternatively spliced connecting segment 1 of fibronectin, as well as vascular cell adhesion molecule-1 and increases migration. Integrin α4 expression enhanced experimental metastasis in a syngeneic tumor model, reconstituting a pattern of organ involvement similar to that seen in patients. Accordingly, antagonism of integrin α4 blocked metastasis, suggesting adhesive function of the integrin is required. However, adhesive function was not sufficient, as mutants of integrin α4 that conserved the matrix-adhesive and promigratory function in vitro were compromised in their metastatic capacity in vivo. Clinically, integrin α4 is more frequently expressed in non-MYNC amplified tumors, and is selectively associated with poor prognosis in this subset of disease. These results reveal an unexpected role for integrin α4 in neuroblastoma dissemination and identify α4 as a potential prognostic indicator and therapeutic target.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0120815PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4431816PMC
April 2016

Gastrin-stimulated Gα13 Activation of Rgnef Protein (ArhGEF28) in DLD-1 Colon Carcinoma Cells.

J Biol Chem 2015 Jun 28;290(24):15197-209. Epub 2015 Apr 28.

From the Molecular Biology Institute of Barcelona, Spanish National Research Council (CSIC), 08028 Barcelona, Spain,

The guanine nucleotide exchange factor Rgnef (also known as ArhGEF28 or p190RhoGEF) promotes colon carcinoma cell motility and tumor progression via interaction with focal adhesion kinase (FAK). Mechanisms of Rgnef activation downstream of integrin or G protein-coupled receptors remain undefined. In the absence of a recognized G protein signaling homology domain in Rgnef, no proximal linkage to G proteins was known. Utilizing multiple methods, we have identified Rgnef as a new effector for Gα13 downstream of gastrin and the type 2 cholecystokinin receptor. In DLD-1 colon carcinoma cells depleted of Gα13, gastrin-induced FAK Tyr(P)-397 and paxillin Tyr(P)-31 phosphorylation were reduced. RhoA GTP binding and promoter activity were increased by Rgnef in combination with active Gα13. Rgnef co-immunoprecipitated with activated Gα13Q226L but not Gα12Q229L. The Rgnef C-terminal (CT, 1279-1582) region was sufficient for co-immunoprecipitation, and Rgnef-CT exogenous expression prevented Gα13-stimulated SRE activity. A domain at the C terminus of the protein close to the FAK binding domain is necessary to bind to Gα13. Point mutations of Rgnef-CT residues disrupt association with active Gα13 but not Gαq. These results show that Rgnef functions as an effector of Gα13 signaling and that this linkage may mediate FAK activation in DLD-1 colon carcinoma cells.
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http://dx.doi.org/10.1074/jbc.M114.628164DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463461PMC
June 2015

FAK activity protects nucleostemin in facilitating breast cancer spheroid and tumor growth.

Breast Cancer Res 2015 Mar 28;17:47. Epub 2015 Mar 28.

Department of Reproductive Medicine, University of California San Diego, Moores Cancer Center, 3855 Health Sciences Dr, La Jolla, CA, 92093, USA.

Introduction: Focal adhesion kinase (FAK) controls cell growth and survival downstream of integrin-matrix receptors. Upon adhesion loss or FAK inhibition, FAK can translocate to the nucleus. The nucleolus is a non-membrane nuclear structure that regulates ribosome biogenesis and cell proliferation. Nucleostemin (NS), a nucleolar-localized protein, modulates cell cycle progression, stemness, and three-dimensional tumor spheroid formation. The signaling pathways that regulate NS levels in tumors remain undefined.

Methods: Human breast carcinoma cells were evaluated for growth in culture (adherent and anchorage-independent spheroid) and as orthotopic tumors. FAK signaling was evaluated by pharmacological FAK inhibitor addition (PF-271, IC50~0.1 μM) and by small hairpin RNA (shRNA) knockdown followed by re-expression of FAK wildtype (WT) or a kinase-dead (KD, K454R) FAK point mutant. Immunoblotting was used to evaluate FAK, NS, nucleolar phosphoprotein B23, and nucleolin levels. Total and phosphospecific antibody imunoblotting were used to detect changes in FAK, Akt kinase (Akt also known as protein kinase B), and 4E-binding protein 1 (4E-BP1) phosphorylation, a translation repressor protein and target of the mammalian target of rapamycin (mTOR) complex. Immunohistochemical, co-immunoprecipitation, and cellular fractionation analyses were used to evaluate FAK association with nucleoli.

Results: Pharmacological (0.1 μM PF-271) or genetic inhibition of FAK activity prevents MDA-MB-231 and 4T1L breast carcinoma growth as spheroids and as orthotopic tumors. FAK inhibition triggers proteasome-mediated decreased NS levels but no changes in other nucleolar proteins such as B23 (nucleophosmin) or nucleolin. Active FAK was associated with purified nucleoli of anchorage-independent cells and present within nucleoli of human invasive ductal carcinoma tumor samples. FAK co-immunoprecipitated with B23 that binds NS and a complex between FAK, NS, Akt, and mTOR was detected. Constitutively-active Akt kinase promoted tumor spheroid growth, stabilized NS levels, and promoted pS65 4E-BP1 phosphorylation in the presence of inhibited FAK. Rapamycin lowered NS levels and inhibited pS65 4E-BP1 phosphorylation in cells with activated Akt-mTOR signaling.

Conclusions: FAK signaling occurs in the nucleolus, active FAK protects NS, and Akt-mTOR pathway regulates NS protein stability needed for breast carcinoma spheroid and tumor growth.
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http://dx.doi.org/10.1186/s13058-015-0551-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4407832PMC
March 2015

FAK in cancer: mechanistic findings and clinical applications.

Nat Rev Cancer 2014 Sep 7;14(9):598-610. Epub 2014 Aug 7.

University of California San Diego, Moores Cancer Center, Department of Reproductive Medicine, 3855 Health Sciences Dr., MC0803, La Jolla, California 92093 USA.

Focal adhesion kinase (FAK) is a cytoplasmic protein tyrosine kinase that is overexpressed and activated in several advanced-stage solid cancers. FAK promotes tumour progression and metastasis through effects on cancer cells, as well as stromal cells of the tumour microenvironment. The kinase-dependent and kinase-independent functions of FAK control cell movement, invasion, survival, gene expression and cancer stem cell self-renewal. Small molecule FAK inhibitors decrease tumour growth and metastasis in several preclinical models and have initial clinical activity in patients with limited adverse events. In this Review, we discuss FAK signalling effects on both tumour and stromal cell biology that provide rationale and support for future therapeutic opportunities.
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http://dx.doi.org/10.1038/nrc3792DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4365862PMC
September 2014

FAK Inhibition disrupts a β5 integrin signaling axis controlling anchorage-independent ovarian carcinoma growth.

Mol Cancer Ther 2014 Aug 4;13(8):2050-61. Epub 2014 Jun 4.

Department of Reproductive Medicine, UCSD Moores Cancer Center, La Jolla, California

Ovarian cancer ascites fluid contains matrix proteins that can impact tumor growth via integrin receptor binding. In human ovarian tumor tissue arrays, we find that activation of the cytoplasmic focal adhesion (FAK) tyrosine kinase parallels increased tumor stage, β5 integrin, and osteopontin matrix staining. Elevated osteopontin, β5 integrin, and FAK mRNA levels are associated with decreased serous ovarian cancer patient survival. FAK remains active within ovarian cancer cells grown as spheroids, and anchorage-independent growth analyses of seven ovarian carcinoma cell lines identified sensitive (HEY, OVCAR8) and resistant (SKOV3-IP, OVCAR10) cells to 0.1 μmol/L FAK inhibitor (VS-4718, formerly PND-1186) treatment. VS-4718 promoted HEY and OVCAR8 G0-G1 cell-cycle arrest followed by cell death, whereas growth of SKOV3-IP and OVCAR10 cells was resistant to 1.0 μmol/L VS-4718. In HEY cells, genetic or pharmacological FAK inhibition prevented tumor growth in mice with corresponding reductions in β5 integrin and osteopontin expression. β5 knockdown reduced HEY cell growth in soft agar, tumor growth in mice, and both FAK Y397 phosphorylation and osteopontin expression in spheroids. FAK inhibitor-resistant (SKOV3-IP, OVCAR10) cells exhibited anchorage-independent Akt S473 phosphorylation, and expression of membrane-targeted and active Akt in sensitive cells (HEY, OVCAR8) increased growth but did not create a FAK inhibitor-resistant phenotype. These results link osteopontin, β5 integrin, and FAK in promoting ovarian tumor progression. β5 integrin expression may serve as a biomarker for serous ovarian carcinoma cells that possess active FAK signaling.
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http://dx.doi.org/10.1158/1535-7163.MCT-13-1063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126870PMC
August 2014

Analyses of merlin/NF2 connection to FAK inhibitor responsiveness in serous ovarian cancer.

Gynecol Oncol 2014 Jul 27;134(1):104-11. Epub 2014 Apr 27.

Department of Reproductive Medicine, UCSD Moores Cancer Center, La Jolla, CA 92093, United States. Electronic address:

Objective: Focal adhesion kinase (FAK) is overexpressed in serous ovarian cancer. Loss of merlin, a product of the neurofibromatosis 2 tumor suppressor gene, is being evaluated as a biomarker for FAK inhibitor sensitivity in mesothelioma. Connections between merlin and FAK in ovarian cancer remain undefined.

Methods: Nine human and two murine ovarian cancer cell lines were analyzed for growth in the presence of a small molecule FAK inhibitor (PF-271, also termed VS-6062) from 0.1 to 1 μM for 72 h. Merlin was evaluated by immunoblotting and immunostaining of a human ovarian tumor tissue array. Growth of cells was analyzed in an orthotopic tumor model and evaluated in vitro after stable shRNA-mediated merlin knockdown.

Results: Greater than 50% inhibition of OVCAR8, HEY, and ID8-IP ovarian carcinoma cell growth occurred with 0.1 μM PF-271 in anchorage-independent (p<0.001) but not in adherent culture conditions. PF-271-mediated reduction in FAK Y397 phosphorylation occurred independently of growth inhibition. Suspended growth of OVCAR3, OVCAR10, IGROV1, IGROV1-IP, SKOV3, SKOV3-IP, A2780, and 5009-MOVCAR was not affected by 0.1 μM PF-271. Merlin expression did not correlate with serous ovarian tumor grade or stage. PF-271 (30 mg/kg, BID) did not inhibit 5009-MOVCAR tumor growth and merlin knockdown in SKOV3-IP and OVCAR10 cells did not alter suspended cell growth upon PF-271 addition.

Conclusions: Differential responsiveness to FAK inhibitor treatment was observed. Intrinsic low merlin protein level correlated with PF-271-mediated anchorage-independent growth inhibition, but reduction in merlin expression did not induce sensitivity to FAK inhibition. Merlin levels may be useful for patient stratification in FAK inhibitor trials.
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http://dx.doi.org/10.1016/j.ygyno.2014.04.044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4065804PMC
July 2014

Inhibition of endothelial FAK activity prevents tumor metastasis by enhancing barrier function.

J Cell Biol 2014 Jan;204(2):247-63

Department of Reproductive Medicine and 2 Department of Pathology, Moores University of California, San Diego Cancer Center, La Jolla, CA 92093.

Pharmacological focal adhesion kinase (FAK) inhibition prevents tumor growth and metastasis, via actions on both tumor and stromal cells. In this paper, we show that vascular endothelial cadherin (VEC) tyrosine (Y) 658 is a target of FAK in tumor-associated endothelial cells (ECs). Conditional kinase-dead FAK knockin within ECs inhibited recombinant vascular endothelial growth factor (VEGF-A) and tumor-induced VEC-Y658 phosphorylation in vivo. Adherence of VEGF-expressing tumor cells to ECs triggered FAK-dependent VEC-Y658 phosphorylation. Both FAK inhibition and VEC-Y658F mutation within ECs prevented VEGF-initiated paracellular permeability and tumor cell transmigration across EC barriers. In mice, EC FAK inhibition prevented VEGF-dependent tumor cell extravasation and melanoma dermal to lung metastasis without affecting primary tumor growth. As pharmacological c-Src or FAK inhibition prevents VEGF-stimulated c-Src and FAK translocation to EC adherens junctions, but FAK inhibition does not alter c-Src activation, our experiments identify EC FAK as a key intermediate between c-Src and the regulation of EC barrier function controlling tumor metastasis.
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http://dx.doi.org/10.1083/jcb.201307067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897185PMC
January 2014

Grb2 promotes integrin-induced focal adhesion kinase (FAK) autophosphorylation and directs the phosphorylation of protein tyrosine phosphatase α by the Src-FAK kinase complex.

Mol Cell Biol 2014 Feb 18;34(3):348-61. Epub 2013 Nov 18.

Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.

The integrin-activated Src-focal adhesion kinase (FAK) kinase complex phosphorylates PTPα at Tyr789, initiating PTPα-mediated signaling that promotes cell migration. Recruitment of the BCAR3-Cas complex by PTPα-phospho-Tyr789 at focal adhesions is one mechanism of PTPα signaling. The adaptor protein Grb2 is also recruited by PTPα-phospho-Tyr789, although the role of the PTPα-Grb2 complex in integrin signaling is unknown. We show that silencing Grb2 expression in fibroblasts abolishes PTPα-Tyr789 phosphorylation and that this is due to two unexpected actions of Grb2. First, Grb2 promotes integrin-induced autophosphorylation of FAK-Tyr397. This is impaired in Grb2-depleted cells and prohibits FAK activation and formation of the Src-FAK complex. Grb2-depleted cells contain less paxillin, and paxillin overexpression rescues FAK-Tyr397 phosphorylation, suggesting that the FAK-activating action of Grb2 involves paxillin. A second distinct role for Grb2 in PTPα-Tyr789 phosphorylation involves Grb2-mediated coupling of Src-FAK and PTPα. This requires two phosphosites, FAK-Tyr925 and PTPα-Tyr789, for Grb2-Src homology 2 (SH2) binding. We propose that a Grb2 dimer links FAK and PTPα, and this positions active Src-FAK in proximity with other, perhaps integrin-clustered, molecules of PTPα to enable maximal PTPα-Tyr789 phosphorylation. These findings identify Grb2 as a new FAK activator and reveal its essential role in coordinating PTPα tyrosine phosphorylation to enable downstream integrin signaling and migration.
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http://dx.doi.org/10.1128/MCB.00825-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3911518PMC
February 2014

pHocal adhesion kinase regulation is on a FERM foundation.

J Cell Biol 2013 Sep;202(6):833-6

Department of Reproductive Medicine, Moores UCSD Cancer Center, La Jolla, CA 92093.

Increases in intracellular pH (pHi) occur upon integrin receptor binding to matrix proteins and in tumor cells. In this issue, Choi et al. (2013. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201308034) show that pHi increase activates FAK by causing deprotonation of histidine 58 in its FERM (band 4.1, ezrin, radixin, moesin) homology domain, which exposes a region important for FAK autophosphorylation. This model of FAK activation could contribute to motility of tumor cells by promoting focal adhesion turnover.
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http://dx.doi.org/10.1083/jcb.201308034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3776349PMC
September 2013

A non-canonical role for Rgnef in promoting integrin-stimulated focal adhesion kinase activation.

J Cell Sci 2013 Nov 4;126(Pt 21):5074-85. Epub 2013 Sep 4.

Moores UCSD Cancer Center, La Jolla, CA 92093, USA.

Rgnef (also known as p190RhoGEF or ARHGEF28) is a Rho guanine-nucleotide-exchange factor (GEF) that binds focal adhesion kinase (FAK). FAK is recruited to adhesions and activated by integrin receptors binding to matrix proteins, such as fibronectin (FN). Canonical models place Rgnef downstream of integrin-FAK signaling in regulating Rho GTPase activity and cell movement. Herein, we establish a new, upstream role for Rgnef in enhancing FAK localization to early peripheral adhesions and promoting FAK activation upon FN binding. Rgnef-null mouse embryo fibroblasts (MEFs) exhibit defects in adhesion formation, levels of FAK phosphotyrosine (pY)-397 and FAK localization to peripheral adhesions upon re-plating on FN. Rgnef re-expression rescues these defects, but requires Rgnef-FAK binding. A mutation in the Rgnef pleckstrin homology (PH) domain inhibits adhesion formation, FAK localization, and FAK-Y397 and paxillin-Y118 phosphorylation without disrupting the Rgnef-FAK interaction. A GEF-inactive Rgnef mutant rescues FAK-Y397 phosphorylation and early adhesion localization, but not paxillin-Y118 phosphorylation. This suggests that, downstream of FN binding, paxillin-pY118 requires Rgnef GEF activity through a mechanism distinct from adhesion formation and FAK activation. These results support a scaffolding role for Rgnef in FAK localization and activation at early adhesions in a PH-domain-dependent but GEF-activity-independent manner.
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http://dx.doi.org/10.1242/jcs.135509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3820247PMC
November 2013

Inhibition of focal adhesion kinase (FAK) activity prevents anchorage-independent ovarian carcinoma cell growth and tumor progression.

Clin Exp Metastasis 2013 Jun 30;30(5):579-94. Epub 2012 Dec 30.

Department of Reproductive Medicine, Moores UCSD Cancer Center, University of California San Diego, La Jolla, CA 92093, USA.

Recurrence and spread of ovarian cancer is the 5th leading cause of death for women in the United States. Focal adhesion kinase (FAK) is a cytoplasmic protein-tyrosine kinase located on chromosome 8q24.3 (gene is Ptk2), a site commonly amplified in serous ovarian cancer. Elevated FAK mRNA levels in serous ovarian carcinoma are associated with decreased (logrank P = 0.0007, hazard ratio 1.43) patient overall survival, but how FAK functions in tumor progression remains undefined. We have isolated aggressive ovarian carcinoma cells termed ID8-IP after intraperitoneal (IP) growth of murine ID8 cells in C57Bl6 mice. Upon orthotopic implantation within the peri-ovarian bursa space, ID8-IP cells exhibit greater tumor growth, local and distant metastasis, and elevated numbers of ascites-associated cells compared to parental ID8 cells. ID8-IP cells exhibit enhanced growth under non-adherent conditions with elevated FAK and c-Src tyrosine kinase activation compared to parental ID8 cells. In vitro, the small molecule FAK inhibitor (Pfizer, PF562,271, PF-271) at 0.1 uM selectively prevented anchorage-independent ID8-IP cell growth with the inhibition of FAK tyrosine (Y)397 but not c-Src Y416 phosphorylation. Oral PF-271 administration (30 mg/kg, twice daily) blocked FAK but not c-Src tyrosine phosphorylation in ID8-IP tumors. This was associated with decreased tumor size, prevention of peritoneal metastasis, reduced tumor-associated endothelial cell number, and increased tumor cell-associated apoptosis. FAK knockdown and re-expression assays showed that FAK activity selectively promoted anchorage-independent ID8-IP cell survival. These results support the continued evaluation of FAK inhibitors as a promising clinical treatment for ovarian cancer.
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http://dx.doi.org/10.1007/s10585-012-9562-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3622195PMC
June 2013

Tetraspan TM4SF5-dependent direct activation of FAK and metastatic potential of hepatocarcinoma cells.

J Cell Sci 2012 Dec 17;125(Pt 24):5960-73. Epub 2012 Oct 17.

Interdisciplinary Program in Genetic Engineering, Research Institute of Pharmaceutical Sciences, Medicinal Bioconvergence Research Center, College of Pharmacy, Seoul National University, Seoul 151-742, Korea (Republic of).

Transmembrane 4 L six family member 5 (TM4SF5) plays an important role in cell migration, and focal adhesion kinase (FAK) activity is essential for homeostatic and pathological migration of adherent cells. However, it is unclear how TM4SF5 signaling mediates the activation of cellular migration machinery, and how FAK is activated during cell adhesion. Here, we showed that direct and adhesion-dependent binding of TM4SF5 to FAK causes a structural alteration that may release the inhibitory intramolecular interaction in FAK. In turn, this may activate FAK at the cell's leading edge, to promote migration/invasion and in vivo metastasis. TM4SF5-mediated FAK activation occurred during integrin-mediated cell adhesion. TM4SF5 was localized at the leading edge of the cells, together with FAK and actin-organizing molecules, indicating a signaling link between TM4SF5/FAK and actin reorganization machinery. Impaired interactions between TM4SF5 and FAK resulted in an attenuated FAK phosphorylation (the signaling link to actin organization machinery) and the metastatic potential. Our findings demonstrate that TM4SF5 directly binds to and activates FAK in an adhesion-dependent manner, to regulate cell migration and invasion, suggesting that TM4SF5 is a promising target in the treatment of metastatic cancer.
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http://dx.doi.org/10.1242/jcs.100586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4074290PMC
December 2012

Integrin adhesions: who's on first? What's on second? Connections between FAK and talin.

Cell Adh Migr 2012 Jul-Aug;6(4):302-6. Epub 2012 Jul 1.

Department of Reproductive Medicine, Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093 USA.

Cell migration requires the coordination of adhesion site assembly and turnover. Canonical models for nascent adhesion formation postulate that integrin binding to extracellular matrix (ECM) proteins results in the rapid recruitment of cytoskeletal proteins such as talin and paxillin to integrin cytoplasmic domains. It is thought that integrin-talin clusters recruit and activate tyrosine kinases such as focal adhesion kinase (FAK). However, the molecular connections of this linkage remain unresolved. Our recent findings support an alternative model whereby FAK recruits talin to new sites of β1 integrin-mediated adhesion in mouse embryonic fibroblasts and human ovarian carcinoma cells. This is dependent on a direct binding interaction between FAK and talin and occurs independently of direct talin binding to β1 integrin. Herein, we discuss differences between nascent and mature adhesions, interactions between FAK, talin and paxillin, possible mechanisms of FAK activation and how this FAK-talin complex may function to promote cell motility through increased adhesion turnover.
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http://dx.doi.org/10.4161/cam.20488DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3478250PMC
February 2013

Cortactin as a target for FAK in the regulation of focal adhesion dynamics.

PLoS One 2012 29;7(8):e44041. Epub 2012 Aug 29.

Moores University of California San Diego Cancer Center, University of California San Diego, La Jolla, California, USA.

Background: Efficient cell movement requires the dynamic regulation of focal adhesion (FA) formation and turnover. FAs are integrin-associated sites of cell attachment and establish linkages to the cellular actin cytoskeleton. Cells without focal adhesion kinase (FAK), an integrin-activated tyrosine kinase, exhibit defects in FA turnover and cell motility. Cortactin is an actin binding adaptor protein that can influence FA dynamics. FAK and cortactin interact, but the cellular role of this complex remains unclear.

Principal Findings: Using FAK-null fibroblasts stably reconstituted with green fluorescent protein (GFP) tagged FAK constructs, we find that FAK activity and FAK C-terminal proline-rich region 2 (PRR2) and PRR3 are required for FA turnover and cell motility. Cortactin binds directly to FAK PRR2 and PRR3 sites via its SH3 domain and cortactin expression is important in promoting FA turnover and GFP-FAK release from FAs. FAK-cortactin binding is negatively-regulated by FAK activity and associated with cortactin tyrosine phosphorylation. FAK directly phosphorylates cortactin at Y421 and Y466 and over-expression of cortactin Y421, Y466, and Y482 mutated to phenylalanine (3YF) prevented FAK-enhanced FA turnover and cell motility. However, phospho-mimetic cortactin mutated to glutamic acid (3YE) did not affect FA dynamics and did not rescue FA turnover defects in cells with inhibited FAK activity or with PRR2-mutated FAK that does not bind cortactin.

Conclusions: Our results support a model whereby FAK-mediated FA remodeling may occur through the formation of a FAK-cortactin signaling complex. This involves a cycle of cortactin binding to FAK, cortactin tyrosine phosphorylation, and subsequent cortactin-FAK dissociation accompanied by FA turnover and cell movement.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0044041PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3430618PMC
February 2013

Nuclear-localized focal adhesion kinase regulates inflammatory VCAM-1 expression.

J Cell Biol 2012 Jun;197(7):907-19

Department of Reproductive Medicine, University of California-San Diego, Moores Cancer Center, La Jolla, CA 92093, USA.

Vascular cell adhesion molecule-1 (VCAM-1) plays important roles in development and inflammation. Tumor necrosis factor-α (TNF-α) and focal adhesion kinase (FAK) are key regulators of inflammatory and integrin-matrix signaling, respectively. Integrin costimulatory signals modulate inflammatory gene expression, but the important control points between these pathways remain unresolved. We report that pharmacological FAK inhibition prevented TNF-α-induced VCAM-1 expression within heart vessel-associated endothelial cells in vivo, and genetic or pharmacological FAK inhibition blocked VCAM-1 expression during development. FAK signaling facilitated TNF-α-induced, mitogen-activated protein kinase activation, and, surprisingly, FAK inhibition resulted in the loss of the GATA4 transcription factor required for TNF-α-induced VCAM-1 production. FAK inhibition also triggered FAK nuclear localization. In the nucleus, the FAK-FERM (band 4.1, ezrin, radixin, moesin homology) domain bound directly to GATA4 and enhanced its CHIP (C terminus of Hsp70-interacting protein) E3 ligase-dependent polyubiquitination and degradation. These studies reveal new developmental and anti-inflammatory roles for kinase-inhibited FAK in limiting VCAM-1 production via nuclear localization and promotion of GATA4 turnover.
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http://dx.doi.org/10.1083/jcb.201109067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3384409PMC
June 2012
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