Multisite Phosphorylation of S6K1 Directs a Kinase Phospho-code that Determines Substrate Selection.

Multisite phosphorylation of kinases can induce on-off or graded regulation of catalytic activity; however, its influence on substrate specificity remains unclear. Here, we show that multisite phosphorylation of ribosomal protein S6 kinase 1 (S6K1) alters target selection. Agonist-inducible phosphorylation of glutamyl-prolyl tRNA synthetase (EPRS) by S6K1 in monocytes and adipocytes requires not only canonical phosphorylation at Thr389 by mTORC1 but also phosphorylation at Ser424 and Ser429 in the C terminus by cyclin-dependent kinase 5 (Cdk5). S6K1 phosphorylation at these additional sites induces a conformational switch and is essential for high-affinity binding and phosphorylation of EPRS, but not canonical S6K1 targets, e.g., ribosomal protein S6. Unbiased proteomic analysis identified additional targets phosphorylated by multisite phosphorylated S6K1 in insulin-stimulated adipocytes-namely, coenzyme A synthase, lipocalin 2, and cortactin. Thus, embedded within S6K1 is a target-selective kinase phospho-code that integrates signals from mTORC1 and Cdk5 to direct an insulin-stimulated, post-translational metabolon determining adipocyte lipid metabolism.

MCT4 and CD147 colocalize with MMP14 in invadopodia and support matrix degradation and invasion by breast cancer cells.

Expression levels of the lactate-H+ cotransporter MCT4 (also known as SLC16A3) and its chaperone CD147 (also known as basigin) are upregulated in breast cancers, correlating with decreased patient survival. Here, we test the hypothesis that MCT4 and CD147 favor breast cancer invasion through interdependent effects on extracellular matrix (ECM) degradation. MCT4 and CD147 expression and membrane localization were found to be strongly reciprocally interdependent in MDA-MB-231 breast cancer cells. Overexpression of MCT4 and/or CD147 increased, and their knockdown decreased, migration, invasion and the degradation of fluorescently labeled gelatin. Overexpression of both proteins led to increases in gelatin degradation and appearance of the matrix metalloproteinase (MMP)-generated collagen-I cleavage product reC1M, and these increases were greater than those observed upon overexpression of each protein alone, suggesting a concerted role in ECM degradation. MCT4 and CD147 colocalized with invadopodia markers at the plasma membrane. They also colocalized with MMP14 and the lysosomal marker LAMP1, as well as partially with the autophagosome marker LC3, in F-actin-decorated intracellular vesicles. We conclude that MCT4 and CD147 reciprocally regulate each other and interdependently support migration and invasiveness of MDA-MB-231 breast cancer cells. Mechanistically, this involves MCT4-CD147-dependent stimulation of ECM degradation and specifically of MMP-mediated collagen-I degradation. We suggest that the MCT4-CD147 complex is co-delivered to invadopodia with MMP14.

Cortactin: A major cellular target of viral, protozoal, and fungal pathogens.

Many viral, protozoal, and fungal pathogens represent major human and animal health problems due to their great potential of causing infectious diseases. Research on these pathogens has contributed substantially to our current understanding of both microbial virulence determinants and host key factors during infection. Countless studies have also shed light on the molecular mechanisms of host-pathogen interactions that are employed by these microbes. For example, actin cytoskeletal dynamics play critical roles in effective adhesion, host cell entry, and intracellular movements of intruding pathogens. Cortactin is an eminent host cell protein that stimulates actin polymerization and signal transduction, and recently emerged as fundamental player during host-pathogen crosstalk. Here we review the important role of cortactin as major target for various prominent viral, protozoal and fungal pathogens in humans, and its role in human disease development and cancer progression. Most if not all of these important classes of pathogens have been reported to hijack cortactin during infection through mediating up- or downregulation of cortactin mRNA and protein expression as well as signaling. In particular, pathogen-induced changes in tyrosine and serine phosphorylation status of cortactin at its major phospho-sites (Y-421, Y-470, Y-486, S-113, S-298, S-405, and S-418) are addressed. As has been reported for various Gram-negative and Gram-positive bacteria, many pathogenic viruses, protozoa, and fungi also control these regulatory phospho-sites, for example, by activating kinases such as Src, PAK, ERK1/2, and PKD, which are known to phosphorylate cortactin. In addition, the recruitment of cortactin and its interaction partners, like the Arp2/3 complex and F-actin, to the contact sites between pathogens and host cells is highlighted, as this plays an important role in the infection process and internalization of several pathogens. However, there are also other ways in which the pathogens can exploit the function of cortactin for their needs, as the cortactin-mediated regulation of cellular processes is complex and involves numerous different interaction partners. Here, the current state of knowledge is summarized.

Cortactin controls bone homeostasis through regulating the differentiation of osteoblasts and osteoclasts.

Cortactin (CTTN), a cytoskeletal protein and substrate of Src kinase, is implicated in tumor aggressiveness. However, its role in bone cell differentiation remains unknown. The current study revealed that CTTN was upregulated during osteoblast and adipocyte differentiation. Functional experiments demonstrated that CTTN promoted the in vitro differentiation of mesenchymal stem/progenitor cells into osteogenic and adipogenic lineages. Mechanistically, CTTN was able to stabilize the protein level of mechanistic target of rapamycin kinase (mTOR), leading to the activation of mTOR signaling. In-depth investigation revealed that CTTN could bind with casitas B lineage lymphoma-c (c-CBL) and counteract the function of c-CBL, a known E3 ubiquitin ligase responsible for the proteasomal degradation of mTOR. Silencing c-Cbl alleviated the impaired differentiation of osteoblasts and adipocytes caused by CTTN siRNA, while silencing mTOR mitigated the stimulation of osteoblast and adipocyte differentiation induced by CTTN overexpression. Notably, transplantation of CTTN-silenced bone marrow stromal cells (BMSCs) into the marrow of mice led to a reduction in trabecular bone mass, accompanied by a decrease in osteoblasts and an increase in osteoclasts. Furthermore, CTTN-silenced BMSCs expressed higher levels of receptor activator of nuclear factor κB ligand (RANKL) than control BMSCs did and promoted osteoclast differentiation when cocultured with bone marrow-derived osteoclast precursor cells. This study provides evidence that CTTN favors osteoblast differentiation by counteracting the c-CBL-induced degradation of mTOR and inhibits osteoclast differentiation by downregulating the expression of RANKL. It also suggests that maintaining an appropriate level of CTTN expression may be advantageous for maintaining bone homeostasis.

Requirement of Site-Specific Tyrosine Phosphorylation of Cortactin in Retinal Neovascularization and Vascular Leakage.

BACKGROUND: Retinal neovascularization is a major cause of vision impairment. Therefore, the purpose of this study is to investigate the mechanisms by which hypoxia triggers the development of abnormal and leaky blood vessels. METHODS: A variety of cellular and molecular approaches as well as tissue-specific knockout mice were used to investigate the role of Cttn (cortactin) in retinal neovascularization and vascular leakage. RESULTS: We found that VEGFA (vascular endothelial growth factor A) stimulates Cttn phosphorylation at Y421, Y453, and Y470 residues in human retinal microvascular endothelial cells. In addition, we observed that while blockade of Cttn phosphorylation at Y470 inhibited VEGFA-induced human retinal microvascular endothelial cell angiogenic events, suppression of Y421 phosphorylation protected endothelial barrier integrity from disruption by VEGFA. In line with these observations, while blockade of Cttn phosphorylation at Y470 negated oxygen-induced retinopathy-induced retinal neovascularization, interference with Y421 phosphorylation prevented VEGFA/oxygen-induced retinopathy-induced vascular leakage. Mechanistically, while phosphorylation at Y470 was required for its interaction with Arp2/3 and CDC6 facilitating actin polymerization and DNA synthesis, respectively, Cttn phosphorylation at Y421 leads to its dissociation from VE-cadherin, resulting in adherens junction disruption. Furthermore, whereas Cttn phosphorylation at Y470 residue was dependent on Lyn, its phosphorylation at Y421 residue required Syk activation. Accordingly, lentivirus-mediated expression of shRNA targeting Lyn or Syk levels inhibited oxygen-induced retinopathy-induced retinal neovascularization and vascular leakage, respectively. CONCLUSIONS: The above observations show for the first time that phosphorylation of Cttn is involved in a site-specific manner in the regulation of retinal neovascularization and vascular leakage. In view of these findings, Cttn could be a novel target for the development of therapeutics against vascular diseases such as retinal neovascularization and vascular leakage.

Syntaxin 7 contributes to breast cancer cell invasion by promoting invadopodia formation.

Invasion in various cancer cells requires coordinated delivery of signaling proteins, adhesion proteins, actin-remodeling proteins and proteases to matrix-degrading structures called invadopodia. Vesicular trafficking involving SNAREs plays a crucial role in the delivery of cargo to the target membrane. Screening of 13 SNAREs from the endocytic and recycling route using a gene silencing approach coupled with functional assays identified syntaxin 7 (STX7) as an important player in MDA-MB-231 cell invasion. Total internal reflection fluorescence microscopy (TIRF-M) studies revealed that STX7 resides near invadopodia and co-traffics with MT1-MMP (also known as MMP14), indicating a possible role for this SNARE in protease trafficking. STX7 depletion reduced the number of invadopodia and their associated degradative activity. Immunoprecipitation studies revealed that STX7 forms distinct SNARE complexes with VAMP2, VAMP3, VAMP7, STX4 and SNAP23. Depletion of VAMP2, VAMP3 or STX4 abrogated invadopodia formation, phenocopying what was seen upon lack of STX7. Whereas depletion of STX4 reduced MT1-MMP level at the cell surfaces, STX7 silencing significantly reduced the invadopodia-associated MT1-MMP pool and increased the non-invadosomal pool. This study highlights STX7 as a major contributor towards the invadopodia formation during cancer cell invasion. This article has an associated First Person interview with the first author of the paper.

Respiratory syncytial virus disrupts the airway epithelial barrier by decreasing cortactin and destabilizing F-actin.

Respiratory syncytial virus (RSV) infection is the leading cause of acute lower respiratory tract infection in young children worldwide. Our group recently revealed that RSV infection disrupts the airway epithelial barrier in vitro and in vivo. However, the underlying molecular pathways were still elusive. Here, we report the critical roles of the filamentous actin (F-actin) network and actin-binding protein cortactin in RSV infection. We found that RSV infection causes F-actin depolymerization in 16HBE cells, and that stabilizing the F-actin network in infected cells reverses the epithelial barrier disruption. RSV infection also leads to significantly decreased cortactin in vitro and in vivo. Cortactin-knockout 16HBE cells presented barrier dysfunction, whereas overexpression of cortactin protected the epithelial barrier against RSV. The activity of Rap1 (which has Rap1A and Rap1B forms), one downstream target of cortactin, declined after RSV infection as well as in cortactin-knockout cells. Moreover, activating Rap1 attenuated RSV-induced epithelial barrier disruption. Our study proposes a key mechanism in which RSV disrupts the airway epithelial barrier via attenuating cortactin expression and destabilizing the F-actin network. The identified pathways will provide new targets for therapeutic intervention toward RSV-related disease. This article has an associated First Person interview with the first author of the paper.

The stabilization of Arp2/3 complex generated actin filaments.

The Arp2/3 complex, which generates both branched but also linear actin filaments via activation of SPIN90, is evolutionarily conserved in eukaryotes. Several factors regulate the stability of filaments generated by the Arp2/3 complex to maintain the dynamics and architecture of actin networks. In this review, we summarise recent studies on the molecular mechanisms governing the tuning of Arp2/3 complex nucleated actin filaments, which includes investigations using microfluidics and single-molecule imaging to reveal the mechanosensitivity, dissociation and regeneration of actin branches. We also discuss the high-resolution cryo-EM structure of cortactin bound to actin branches, as well as the differences and similarities between the stability of Arp2/3 complex nucleated branches and linear filaments. These new studies provide a clearer picture of the stabilisation of Arp2/3 nucleated filaments at the molecular level. We also identified gaps in our understanding of how different factors collectively contribute to the stabilisation of Arp2/3 complex-generated actin networks.

Gastric Epithelial Barrier Disruption, Inflammation and Oncogenic Signal Transduction by Helicobacter pylori.

Helicobacter pylori exemplifies one of the most favourable bacterial pathogens worldwide. The bacterium colonizes the gastric mucosa in about half of the human population and constitutes a major risk factor for triggering gastric diseases such as stomach cancer. H. pylori infection represents a prime example of chronic inflammation and cancer-inducing bacterial pathogens. The microbe utilizes a remarkable set of virulence factors and strategies to control cellular checkpoints of inflammation and oncogenic signal transduction. This chapter emphasizes on the pathogenicity determinants of H. pylori such as the cytotoxin-associated genes pathogenicity island (cagPAI)-encoded type-IV secretion system (T4SS), effector protein CagA, lipopolysaccharide (LPS) metabolite ADP-glycero-ß-D-manno-heptose (ADP-heptose), cytotoxin VacA, serine protease HtrA, and urease, and how they manipulate various key host cell signaling networks in the gastric epithelium. In particular, we highlight the H. pylori-induced disruption of cell-to-cell junctions, pro-inflammatory activities, as well as proliferative, pro-apoptotic and anti-apoptotic responses. Here we review these hijacked signal transduction events and their impact on gastric disease development.

Targeting cholesterol impairs cell invasion of all breast cancer types.

BACKGROUND: Breast cancer clinical outcome relies on its intrinsic molecular subtype and mortality is almost exclusively due to metastasis, whose mechanism remains unclear. We recently revealed the specific contribution of plasma membrane cholesterol to the invasion of malignant MCF10CAIa but not premalignant MCF10AT and normal MCF10A cell lines in 2D, through invadopodia formation and extracellular matrix (ECM) degradation. In the present study, we address the impact of breast cancer subtypes, mutations and aggressiveness on cholesterol implication in breast cancer cell invasion and 3D spheroid invasion and growth. METHODS: We used nine breast cancer cell lines grouped in four subtypes matching breast tumor classification. Four of these cell lines were also used to generate 3D spheroids. These cell lines were compared for cell invasion in 2D and 3D, spheroid growth in 3D, gelatin degradation, cortactin expression, activation and subcellular distribution as well as cell surface cholesterol distribution and lipid droplets. The effect of plasma membrane cholesterol depletion on all these parameters was determined in parallel and systematically compared with the impact of global matrix metalloproteinase (MMP) inhibition. RESULTS: The six invasive cell lines in 2D were sensitive to partial cholesterol depletion, independently of their subtype, aggressiveness or mutation. Nevertheless, the effect was stronger in the three cell lines able to degrade gelatin. 3D spheroid invasion was also reduced after cholesterol depletion in all breast cancer subtypes tested. Notably, targeting cholesterol was more powerful than MMP inhibition in reducing invasion in both 2D and 3D culture models. Moreover, cholesterol depletion in the six invasive cell lines impaired cortactin distribution in the perinuclear region where invadopodia localized. Breast cancer cell line aggressiveness relied on cholesterol-enriched domains at the ECM-free side and intracellular lipid droplets. Furthermore, the three gelatin-degrading cell lines were characterized by increased cholesterol-enriched submicrometric domains at their ECM-contact side. CONCLUSION: Together, our data suggest cell surface cholesterol combined with lipid droplet labeling as a breast cancer cell aggressiveness marker. They also open the way to test other cholesterol-targeting drugs in more complex models to further evaluate whether cholesterol could represent a strategy in breast cancer therapy.

Binding of USP4 to cortactin enhances cell migration in HCT116 human colon cancer cells.

Ubiquitin-specific protease 4 (USP4) is highly overexpressed in colon cancer and acts as a potent protooncogenic protein by deubiquitinating ß-catenin. However, its prominent roles in tumor formation and migration in cancer cells are not fully understood by its deubiquitinating enzyme (DUB) activity on ß-catenin. Thus, we investigated an additional role of USP4 in cancer. In this study, we identified cortactin (CTTN), an actin-binding protein involved in the regulation of cytoskeleton dynamics and a potential prognostic marker for cancers, as a new cellular interacting partner of USP4 from proximal labeling of HCT116 cells. Additionally, the role of USP4 in CTTN activation and promotion of cell dynamics and migration was investigated in HCT116 cells. We confirmed that interacting of USP4 with CTTN increased cell movement. This finding was supported by the fact that USP4 overexpression in HCT116 cells with reduced expression of CTTN was insufficient to promote cell migration. Additionally, we observed that USP4 overexpression led to a significant increase in CTTN phosphorylation, which is a requisite mechanism for cell migration, by regulating Src/focal adhesion kinase (FAK) binding to CTTN and its activation. Our results suggest that USP4 plays a dual role in cancer progression, including stabilization of ß-catenin as a DUB and interaction with CTTN to promote cell dynamics by inducing CTTN phosphorylation. Therefore, this study demonstrates that USP4 is important for cancer progression and is a good target for treating or preventing cancer.

Analysis of Genes Related to Invadopodia Formation and CTTN in Oral Squamous Cell Carcinoma-A Systematic Gene Expression Analysis.

Successful treatment for any type of carcinoma largely depends on understanding the patterns of invasion and migration. For oral squamous cell carcinoma (OSCC), these processes are not entirely understood as of now. Invadopodia and podosomes, called invadosomes, play an important role in cancer cell invasion and migration. Previous research has established that cortactin (CTTN) is a major inducer of invadosome formation. However, less is known about the expression patterns of CTTN and other genes related to it or invadopodia formation in OSCC during tumor progression in particular. In this study, gene expression patterns of CTTN and various genes (n = 36) associated with invadopodia formation were analyzed to reveal relevant expression patterns and give a comprehensive overview of them. The genes were analyzed from a whole genome dataset of 83 OSCC samples relating to tumor size, grading, lymph node status, and UICC (Union for Internatioanl Cancer Control). The data revealed significant overexpression of 18 genes, most notably CTTN, SRC (SRC proto-onocogene, non-receptor tyrosine kinase), EGFR (epidermal growth factor receptor), SYK (spleen associated tyrosine kinase), WASL (WASP like actin nucleation promotion factor), and ARPC2 (arrestin beta 1) due to their significant correlation with further tumor parameters. This study is one of the first to summarize the expression patterns of CTTN and related genes in a complex group of OSCC samples.

Cortactin: A universal host cytoskeletal target of Gram-negative and Gram-positive bacterial pathogens.

Pathogenic bacteria possess a great potential of causing infectious diseases and represent a serious threat to human and animal health. Understanding the molecular basis of infection development can provide new valuable strategies for disease prevention and better control. In host-pathogen interactions, actin-cytoskeletal dynamics play a crucial role in the successful adherence, invasion, and intracellular motility of many intruding microbial pathogens. Cortactin, a major cellular factor that promotes actin polymerization and other functions, appears as a central regulator of host-pathogen interactions and different human diseases including cancer development. Various important microbes have been reported to hijack cortactin signaling during infection. The primary regulation of cortactin appears to proceed via serine and/or tyrosine phosphorylation events by upstream kinases, acetylation, and interaction with various other host proteins, including the Arp2/3 complex, filamentous actin, the actin nucleation promoting factor N-WASP, focal adhesion kinase FAK, the large GTPase dynamin-2, the guanine nucleotide exchange factor Vav2, and the actin-stabilizing protein CD2AP. Given that many signaling factors can affect cortactin activities, several microbes target certain unique pathways, while also sharing some common features. Here we review our current knowledge of the hallmarks of cortactin as a major target for eminent Gram-negative and Gram-positive bacterial pathogens in humans.

Abl2:Cortactin Interactions Regulate Dendritic Spine Stability via Control of a Stable Filamentous Actin Pool.

Dendritic spines act as the receptive contacts at most excitatory synapses. Spines are enriched in a network of actin filaments comprised of two kinetically distinct pools. The majority of spine actin is highly dynamic and regulates spine size, structural plasticity, and postsynaptic density organization. The remainder of the spine actin network is more stable, but the function of this minor actin population is not well understood, as tools to study it have not been available. Previous work has shown that disruption of the Abl2/Arg nonreceptor tyrosine kinase in mice compromises spine stability and size. Here, using cultured hippocampal neurons pooled from both sexes of mice, we provide evidence that binding to cortactin tethers Abl2 in spines, where Abl2 and cortactin maintain the small pool of stable actin required for dendritic spine stability. Using fluorescence recovery after photobleaching of GFP-actin, we find that disruption of Abl2:cortactin interactions eliminates stable actin filaments in dendritic spines, significantly reducing spine density. A subset of spines remaining after Abl2 depletion retain their stable actin pool and undergo activity-dependent spine enlargement, associated with increased cortactin and GluN2B levels. Finally, tonic increases in synaptic activity rescue spine loss following Abl2 depletion by promoting cortactin enrichment in vulnerable spines. Together, our findings strongly suggest that Abl2:cortactin interactions promote spine stability by maintaining pools of stable actin filaments in spines.SIGNIFICANCE STATEMENT Dendritic spines contain two kinetically distinct pools of actin. The more abundant, highly dynamic pool regulates spine shape, size, and plasticity. The function of the smaller, stable actin network is not well understood, as tools to study it have not been available. We demonstrate here that Abl2 and its substrate and interaction partner, cortactin, are essential to maintain the stable pool in spines. Depletion of the stable actin pool via disruption of Abl2 or cortactin, or interactions between the proteins, significantly reduces spine stability. We also provide evidence that tonic increases in synaptic activity promote spine stability via enrichment of cortactin in spines, suggesting that synaptic activity acts on the stable actin pool to stabilize dendritic spines.

Cortactin loss protects against hemin-induced acute lung injury in sickle cell disease.

In patients with sickle cell disease (SCD), acute chest syndrome (ACS) is a common form of acute lung injury and a major cause of morbidity and mortality. The pathophysiology of ACS is complex, and hemin, the prosthetic moiety of hemoglobin, has been implicated in endothelial cell (EC) activation and subsequent acute lung injury (ALI) and ACS in vitro and in animal studies. Here, we examined the role of cortactin (CTTN), a cytoskeletal protein that regulates EC function, in response to hemin-induced ALI and ACS. Cortactin heterozygous (Cttn+/-) mice (n = 8) and their wild-type siblings (n = 8) were irradiated and subsequently received bone marrow cells (BMCs) extruded from the femurs of SCD mice (SS) to generate SS Cttn+/- and SS CttnWT chimeras. Following hemoglobin electrophoretic proof of BMC transplantation, the mice received 35 µmol/kg of hemin. Within 24 h, surviving mice were euthanized, and bronchoalveolar fluid (BAL) and lung samples were analyzed. For in vitro studies, human lung microvascular endothelial cells (HLMVECs) were used to determine hemin-induced changes in gene expression and reactive oxygen species (ROS) generation in cortactin deficiency and control conditions. When compared with wild-type littermates, the mortality for SS Cttn+/- mice trended to be lower after hemin infusion and these mice exhibited less severe lung injury and less necroptotic cell death. In vitro studies confirmed that cortactin deficiency is protective against hemin-induced injury in HMLVECs, by decreasing protein expression of p38/HSP27, improving cell barrier function, and decreasing the production of ROS. Further studies examining the role of CTTN in ACS are warranted and may open a new avenue of potential treatment for this devastating disease.

The Helicobacter pylori type IV secretion system upregulates epithelial cortactin expression by a CagA- and JNK-dependent pathway.

Cortactin represents an important actin-binding factor, which controls actin-cytoskeletal remodelling in host cells. In this way, cortactin has been shown to exhibit crucial functions both for cell movement and tumour cell invasion. In addition, the cortactin gene cttn is amplified in various cancer types of humans. Helicobacter pylori is the causative agent of multiple gastric diseases and represents a significant risk factor for the development of gastric adenocarcinoma. It has been repeatedly shown that H. pylori manipulates cancer-related signal transduction events in infected gastric epithelial cells such as the phosphorylation status of cortactin. In fact, H. pylori modifies the activity of cortactin's binding partners to stimulate changes in the actin-cytoskeleton, cell adhesion and motility. Here we show that H. pylori infection of cultured AGS and Caco-2 cells for 24-48 hr leads to the overexpression of cortactin by 2-3 fold at the protein level. We demonstrate that this activity requires the integrity of the type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI) as well as the translocated effector protein CagA. We further show that ectopic expression of CagA is sufficient to stimulate cortactin overexpression. Furthermore, phosphorylation of CagA at the EPIYA-repeat region is not required, suggesting that this CagA activity proceeds in a phosphorylation-independent fashion. Inhibitor studies further demonstrate that the involved signalling pathway comprises the mitogen-activated protein kinase JNK (c-Jun N-terminal kinase), but not ERK1/2 or p38. Taken together, using H. pylori as a model system, this study discovered a previously unrecognised cortactin activation cascade by a microbial pathogen. We suggest that H. pylori targets cortactin to manipulate the cellular architecture and epithelial barrier functions that can impact gastric cancer development. TAKE AWAYS: Helicobacter pylori infection induces overexpression of cortactin at the protein level Cortactin upregulation requires the T4SS and effector protein CagA Ectopic expression of CagA is sufficient to stimulate cortactin overexpression Overexpression of cortactin proceeds CagA phosphorylation-independent The involved host cell signalling pathway comprises the MAP kinase JNK.

Glandular odontogenic cysts: A collaborative investigation of 22 cases and proteins related to invasiveness.

BACKGROUND: A glandular odontogenic cyst (GOC) has an intriguing, aggressive behaviour whose mechanisms have not yet been clarified. OBJECTIVE: To conduct a collaborative cross-sectional study on the clinical, demographic, microscopic and immunohistochemical characteristics of GOCs, emphasizing the histopathological characteristics and expression of proteins related to invasiveness. METHODS: Twenty-two cases of GOC from three oral and maxillofacial pathology services in Brazil were selected from 1988 to 2018. Clinical and demographic data were collected. Histopathological features were evaluated in detail. Sixteen cases of GOC were also submitted to immunohistochemistry to detect MT1-MMP, TKS4, TKS5 and cortactin, the key regulators of invadopodia formation. RESULTS: Glandular odontogenic cysts were primarily seen in men over 40 years of age, in the posterior mandible and the anterior maxilla as a unilocular, radiolucent lesion. All cases presented hobnail cells, clear cells and variable thickness of the lining epithelium, 3 of the 10 key histopathological parameters to be evaluated in GOCs. Immunohistochemistry revealed a greater expression of the studied proteins in the GOCs than in the controls (p < 0.0001). CONCLUSION: Overexpression of proteins that regulate cell invasiveness was identified, and the present study's findings suggest that invadopodia activity is a possible mechanism used by GOCs to promote local invasion, which could partly explain its intriguing biological behaviour.

Dietary patterns in association with the expression of pro-metastatic genes in primary breast cancer.

PURPOSE: Metastasis is a major leading cause of mortality in female breast cancer (BrCa). Cellular motility is a pathological process of metastasis remarked by the overexpression of cortactin (CTTN), Ras homolog family member-A (RhoA), and Rho-associated kinase (ROCK) genes. Their balance is responsible for upholding the integrity of healthy epithelial cell junctions. This study aimed to explore the associations between a posteriori dietary patterns and the expression levels of pro-metastatic genes in primary BrCa. METHODS: In this consecutive case series, 215 eligible women, newly diagnosed with histologically confirmed non-metastatic BrCa (stage I-IIIA), were recruited from Hospitals in Tabriz, Northwestern Iran (2015-2017). The tumoral expression levels of genes were quantified using real-time reverse transcription-polymerase chain reaction. Dietary data assessment was carried out using a validated food frequency questionnaire. RESULTS: Three dietary patterns were identified using principal component analysis (KMO = 0.699). Adherence to the "vegan" pattern (vegetables, fruits, legumes, nuts, seeds, and whole grains) was inversely associated with the expression levels of RhoA (ORAdj.T3vs.T1 = 0.24, 95%CI 0.07-0.79) and ROCK (ORAdj.T3vs.T1 = 0.26, 95%CI 0.08-0.87). In addition, the highest adherence to the "prudent" pattern (spices, seafood, dairy, and vegetable oils) decreased the odds of overexpressions at RhoA (ORAdj.T3vs.T1 = 0.26, 95%CI 0.08-0.84) and ROCK genes (ORAdj.T3vs.T1 = 0.29, 95%CI 0.09-0.95). The highest adherence to "Western" pattern (meat, processed meat, hydrogenated fat, fast food, refined cereals, sweets, and soft drinks) was a risk factor associated with the overexpression of RhoA (ORAdj.T3vs.T1 = 3.15, 95%CI 1.12-8.85). CONCLUSION: Adherence to healthy dietary patterns was significantly associated with the downregulation of pro-metastatic genes. Findings provided new implications to advance the nutrigenomic knowledge to prevent the odds of over-regulations in pro-metastatic genes of the primary BrCa.

Cortactin in Lung Cell Function and Disease.

Cortactin (CTTN) is an actin-binding and cytoskeletal protein that is found in abundance in the cell cortex and other peripheral structures of most cell types. It was initially described as a target for Src-mediated phosphorylation at several tyrosine sites within CTTN, and post-translational modifications at these tyrosine sites are a primary regulator of its function. CTTN participates in multiple cellular functions that require cytoskeletal rearrangement, including lamellipodia formation, cell migration, invasion, and various other processes dependent upon the cell type involved. The role of CTTN in vascular endothelial cells is particularly important for promoting barrier integrity and inhibiting vascular permeability and tissue edema. To mediate its functional effects, CTTN undergoes multiple post-translational modifications and interacts with numerous other proteins to alter cytoskeletal structures and signaling mechanisms. In the present review, we briefly describe CTTN structure, post-translational modifications, and protein binding partners and then focus on its role in regulating cellular processes and well-established functional mechanisms, primarily in vascular endothelial cells and disease models. We then provide insights into how CTTN function affects the pathophysiology of multiple lung disorders, including acute lung injury syndromes, COPD, and asthma.

[The expression of cortactin in colorectal cancer and its relationship with clinicopathological and prognostic parameters].

Objective: To investigate the expression of cortactin in colorectal cancer and its correlation with clinicopathological parameters and prognosis. Methods: The expressions of cortactin in normal colorectal mucosal tissue and colorectal cancer tissue in paraffin-embedded tissue microarray from 319 patients who were diagnosed as colorectal cancer and treated in Cancer Hospital of Chinese Academy of Medical Sciences from 2006 to 2009 was detected by immunohistochemistry. Kaplan-Meier method and Log rank test were used for survival analysis, and Cox proportional risk regression model was used for multivariate analysis. Results: The positive expression rates of cortactin in colorectal cancer tissue and normal colorectal mucosal tissue were 61.1% (195/319) and 5.6% (18/319, P<0.001), respectively. T-stage, N-stage, American Joint Committee on Cancer (AJCC) stage, degree of tumor differentiation, neural invasion and preoperative carcinoembryonic antigen (CEA) levels were associated with the expression of cortactin (P<0.05). The positive expression of cortactin was associated with poorer disease-free survival (P=0.036) and overall survival (P=0.043), and the effect was more significant in patients with stage Ⅱ to Ⅲ. For patients with stage Ⅱ-Ⅲ colorectal cancer, postoperative adjuvant therapy was associated with disease-free survival (P=0.007) and overall survival (P=0.015). The vascular tumor embolus, pathological type, preoperative CEA level and cortactin expression were independent influencing factors for disease-free survival (P<0.05). The age, AJCC stage, preoperative CEA level and cortactin expression were independent influencing factors for overall survival (P<0.05). Preoperative CEA level and cortactin expression were independent influencing factors for disease-free survival and overall survival (P<0.05). Conclusion: Cortactin is expressed in colorectal cancer and in stage Ⅱ-Ⅲ patients, it is a potential predictor of colorectal cancer prognosis.