Epidermal Growth Factor Signaling Pathway Research Articles

Enhancement of southern flounder (Paralichthys lethostigma) sperm velocity and fertility by direct activation of sperm epidermal growth factor and adenylyl cyclase signaling pathways

Development of southern flounder commercial aquaculture is limited by poor sperm motility and fertility, but the underlying causes and mechanisms regulating sperm motility are unknown. In vitro treatment of southern flounder sperm with progestin hormones rapidly increases velocity (swimming speed), a major component of sperm motility, and also fertility through membrane progestin receptor alpha (mPRα) and increases in Acy (adenylyl cyclase)/cAMP signaling. The progestin-induced increase of Atlantic croaker sperm velocity, is also mediated through epidermal growth factor receptor (Egfr) transactivation resulting in extracellular-regulated kinase 1/2 (Erk1/2) signaling, but its role in regulating southern flounder sperm velocity is unknown. The hypotheses that Egfr transactivation and Erk1/2 signaling mediates progestin-induced increases in sperm velocity and calcium levels in southern flounder, and that direct stimulation of sperm Egfr/Erk1/2 and Acy/cAMP pathways increases sperm fertility in strip spawning trials were tested in the present study. Golf, Egfr, Erk1/2, and protein kinase A were detected on southern flounder sperm by immunocytochemistry. Involvement of Egfr/Erk1/2 signaling in increasing sperm velocity and calcium levels was investigated by preincubating sperm with two EGFR inhibitors, AG1478, and AG825, a matrix metalloproteinase inhibitor, Ilomastat, and two ERK1/2 inhibitors, PD98059, and U0126, for 30 min. Prior to 1 min. Treatment with progestins. Sperm swimming speed was observed under a microscope after activation with a hyperosmotic medium and recorded for 1 min. Whereas treatment with the inhibitors did not alter basal sperm velocity and calcium levels, all of them significantly attenuated velocity and calcium increases in response to progestins. Treatment in vitro for 1 min. With the Egfr agonist, recombinant human EGF (0.1 nM and 100 nM), mimicked the stimulatory effects of progestins on sperm velocity, the increase in calcium, and also fertility in a strip spawning trials with ovulated southern flounder eggs. The results suggest Egfr/Erk1/2 signaling is involved in sperm velocity and fertility responses to progestins in southern flounder. Direct in vitro treatment with the Acy activator, forskolin (10 μM) for 1 min. Mimicked the stimulatory action of progestins on sperm calcium levels, velocity, and fertility, suggesting that Acy/cAMP signaling also mediates increased sperm swimming speed and fertility. Importantly, both EGF and forskolin also directly stimulated southern flounder sperm velocity and fertility at the end of the reproductive season when sperm were no longer responsive to progestins. The results suggest that EGF and forskolin could potentially be used as pharmacological agents to enhance reproductive performance of male southern flounder broodstock.

Prognostic Risk Models Using Epithelial Cells Identify β-Sitosterol as a Potential Therapeutic Target Against Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is an aggressive and fatal malignancy that leads to epithelial cancer. The association between epithelial cell heterogeneity, prognosis, and immune response in this cancer remains uncertain. This study aimed to investigate epithelial cell heterogeneity in ESCC and develop a predictive risk model using the identified cell types. Single-cell RNA sequencing (scRNA-seq) and differential ESCC gene data were accessed from the Gene Expression Omnibus. Functional enrichment analysis, inferCNV, cell development trajectories, and intercellular communication were analyzed following epithelial cell characterization. Differentially expressed ESCC (n = 773) and epithelial cell marker genes (n = 3407) were intersected to obtain core genes, and epithelial cell-related prognostic genes were identified. LASSO regression analysis was used to construct a prognostic model. The external dataset GSE53624 was used to further validate the stability of the model. Drug sensitivity predictions, and immune cell infiltration were analyzed. Molecular docking clarified the possible therapeutic role of β-sitosterol in ESCC. Finally, wound healing assay, cell colony, and transwell assay were constructed to detect the effects of the core gene PDLIM2 on ESCC cell proliferation, invasion, and migration. Eight cell clusters were identified, and epithelial cells were categorized into tumor and paratumor groups. The tumor group possessed more chromosomal variants than the paratumor group. Epithelial cells were associated with multiple cell types and significantly correlated with the Wnt, transforming growth factor, and epidermal growth factor signaling pathways. From 231 intersected genes, five core genes were screened for use in the risk model: CTSL, LAPTM4B, MYO10, NCF2, and PDLIM2. These genes may contribute to the cancerous transformation of normal esophageal epithelial cells and thereby act as biomarkers and potential therapeutic targets in patients with ESCC. β-Sitosterol furthermore displayed excellent docking potential with these genes. Meanwhile, further experiments demonstrated that the gene PDLIM2 plays a major role in the progression of oesophageal squamous carcinoma. We successfully developed a risk model for the prognosis of ESCC based on epithelial cells that addresses the response of ESCC to immunotherapy and offers novel cancer treatment options.

A robust optimal control framework for controlling aberrant RTK signaling pathways in esophageal cancer.

This study presents a new framework for obtaining personalized optimal treatment strategies targeting aberrant signaling pathways in esophageal cancer, such as the epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) signaling pathways. A new pharmacokinetic model is developed taking into account specific heterogeneities of these signaling mechanisms. The optimal therapies are designed to be obtained using a three step process. First, a finite-dimensional constrained optimization problem is solved to obtain the parameters of the pharmacokinetic model, using discrete patient data measurements. Next, a sensitivity analysis is carried out to determine which of the parameters are sensitive to the evolution of the variants of EGF receptors and VEGF receptors. Finally, a second optimal control problem is solved based on the sensitivity analysis results, using a modified pharmacokinetic model that incorporates two representative drugs Trastuzumab and Bevacizumab, targeting EGF and VEGF, respectively. Numerical results with the combination of the two drugs demonstrate the efficiency of the proposed framework.

Hair Follicle Development of Rex Rabbits Is Regulated Seasonally by Wnt10b/β-Catenin, TGFβ-BMP, IGF1, and EGF Signaling Pathways

This experiment was conducted to study the effects of different skinning seasons on the fur quality and hair follicle development of Rex rabbits. A total of 80,150-day-old Rex rabbits were slaughtered on 15 July 2022 (summer), 15 October 2022 (autumn), 15 January 2023 (winter), and 15 April 2023 (spring) in Shandong Province (10 males and 10 females in each season). The results show that the skin weight, skin area, skin thickness, and hair follicle density of the Rex rabbits (at 150 days of age) were lower in summer than in winter (p < 0.05). Moreover, the coat length was shorter in summer than in spring, autumn, and winter (p < 0.05). The shoulder fat weight, perirenal fat weight, and perigastric fat weight of the Rex rabbits in winter were higher than those in summer (p < 0.05). Furthermore, the leptin levels in serum were higher in winter than in summer in the Rex rabbits (p < 0.05). In terms of serum biochemistry, the glucose levels were higher in autumn and winter than in spring and summer (p < 0.05). The cholesterol, high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL) in summer had higher values than in winter in the Rex rabbits (p < 0.05). In winter, the expression of the Wnt10b, catenin beta 1 (CTNNB1), glycogen synthase kinase 3 beta (GSK3β), insulin like growth factor I (IGF-I), Type I insulin-like growth factor receptor (IGF-IR), and epidermal growth factor (EGF) genes was higher (p < 0.05), and the expression of the dickkopf-1 (DDK1), transforming growth factor beta 1 (TGFβ-1), bone morphogenetic protein 2 (BMP2), and bone morphogenetic protein 4 (BMP4) genes was lower than in summer (p < 0.05). In summer, the heat shock 70 kDa protein (HSP70) expression and CTNNB1 protein phosphorylation levels in skin tissue were higher than in spring, autumn, and winter (p < 0.05). In winter, Wnt10b protein expression was higher (p < 0.05), and GSK-3β protein phosphorylation levels were lower than in spring, autumn, and winter (p < 0.05). These results show that the skinning season can affect the production performance and hair follicle development of Rex rabbits. Compared with other seasons, the quality of skin from rabbits slaughtered in winter is better. Seasons may regulate hair follicle development via the Wnt10b/β-catenin, TGFβ-BMP, IGF1, and EGF signaling pathways in Rex rabbits.

Filter inference: A scalable nonlinear mixed effects inference approach for snapshot time series data.

Variability is an intrinsic property of biological systems and is often at the heart of their complex behaviour. Examples range from cell-to-cell variability in cell signalling pathways to variability in the response to treatment across patients. A popular approach to model and understand this variability is nonlinear mixed effects (NLME) modelling. However, estimating the parameters of NLME models from measurements quickly becomes computationally expensive as the number of measured individuals grows, making NLME inference intractable for datasets with thousands of measured individuals. This shortcoming is particularly limiting for snapshot datasets, common e.g. in cell biology, where high-throughput measurement techniques provide large numbers of single cell measurements. We introduce a novel approach for the estimation of NLME model parameters from snapshot measurements, which we call filter inference. Filter inference uses measurements of simulated individuals to define an approximate likelihood for the model parameters, avoiding the computational limitations of traditional NLME inference approaches and making efficient inferences from snapshot measurements possible. Filter inference also scales well with the number of model parameters, using state-of-the-art gradient-based MCMC algorithms such as the No-U-Turn Sampler (NUTS). We demonstrate the properties of filter inference using examples from early cancer growth modelling and from epidermal growth factor signalling pathway modelling.

LY6K depletion modulates TGF-β and EGF signaling.

Lymphocyte antigen 6 complex locus K (LY6K), a glycosylphosphatidylinositol-anchored protein, plays a dynamic role in cancer metastasis. In the current study, we deciphered the effects of LY6K on transforming growth factor-β (TGF-β) and epidermal growth factor (EGF) signaling through clathrin- and caveolin-1 (CAV-1)-mediated endocytosis. Analysis of the TCGA and GTEx dataset were performed to explore the expression and survival of LY6K in cancer patients. Short interfering RNA (siRNA) was used to knockdown the expression of LY6K in human cervical cancer patients. The effect of lack of LY6K on cell proliferation, migration, and invasion was performed, and RT-qPCR and immunoblotting were performed to identify LY6K-affected TGF-β and EGF signaling pathways. Additionally, Immunofluorescence (IF) and transmission electron microscope (TEM) were performed to identify the role of LY6K in CAV-1- and Clathrin-mediated endocytosis. Lymphocyte antigen 6 complex locus K expression level is elevated in higher grade cervical cancer patients correlating with poor overall survival, progression-free survival, and disease-free survival. LY6K-depletion in HeLa and SiHa cancer cells suppressed EGF-induced proliferation and TGF-β-enhanced migration and invasion. Both TGF-β receptor-I (TβRI) and EGF receptor (EGFR) localized at the plasma membrane regardless of LY6K expression, and LY6K bound TβRI irrespective of the presence of TGF-β; however, LY6K did not bind EGFR. LY6K-depleted cells showed impaired Smad2 phosphorylation upon TGF-β treatment and lower proliferation rates following long-term treatment with EGF. We revealed the atypical movement of TβRI and EGFR from plasma membrane upon ligand stimulation in LY6K-depleted cells and an impaired movement of the endocytic proteins clathrin and CAV-1. Our study demonstrates the key role of LY6K in both clathrin- and CAV-1-mediated endocytic pathways regulated by TGF-β and EGF, and it suggests a correlation between LY6K overexpression in cervical cancer cells and poor overall survival.

Protein kinase D1 overexpression potentiates epidermal growth factor signaling pathway in MCF-7 cells.

Protein kinase D1, PKD1, is a serine-threonine kinase implicated in cell proliferation, migration, invasion, and/or apoptosis and its activation by several growth factors sets this enzyme as a key regulator of tumorigenesis and tumor progression. Despite many studies, its role in the regulation of intracellular signaling pathways remains widely disparate and needs to be clarified. By using human breast cancer cells MCF-7, overexpressing or not PKD1, we demonstrated that PKD1 expression level modulated the tumor growth-promoting epidermal growth factor (EGF) signaling pathway. We also showed that EGF acutely stimulated PKD1 phosphorylation with similar time courses both in control and PKD1-overexpressing cells. However, PKD1 overexpression specifically and markedly increased EGF-induced phosphorylation of Akt (onto T308 and S473 residues) and extracellular-regulated protein kinase (ERK1/2). Finally, pharmacological inhibition of PKD1 activity or lowering its expression level using specific siRNAs drastically reduced EGF-stimulated Akt and ERK phosphorylation in PKD1overexpressing cells, but not in control cells. Overall, these results identified the level of PKD1 expression as a key determinant in the regulation of the EGF signaling pathway highlighting its crucial role in a tumorigenic setting.

Potential of Epidermal Growth Factor-like Peptide from the Sea Cucumber Stichopus horrens to Increase the Growth of Human Cells: In Silico Molecular Docking Approach.

The sea cucumber is prominent as a traditional remedy among Asians for wound healing due to its high capacity for regeneration after expulsion of its internal organs. A short peptide consisting of 45 amino acids from transcriptome data of Stichopus horrens (Sh-EGFl-1) shows a convincing capability to promote the growth of human melanoma cells. Molecular docking of Sh-EGFl-1 peptide with human epidermal growth factor receptor (hEGFR) exhibited a favorable intermolecular interaction, where most of the Sh-EGFl-1 residues interacted with calcium binding-like domains. A superimposed image of the docked structure against a human EGF–EGFR crystal model also gave an acceptable root mean square deviation (RMSD) value of less than 1.5 Å. Human cell growth was significantly improved by Sh-EGFl-1 peptide at a lower concentration in a cell proliferation assay. Gene expression profiling of the cells indicated that Sh-EGFl-1 has activates hEGFR through five epidermal growth factor signaling pathways; phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK), phospholipase C gamma (PLC-gamma), Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Ras homologous (Rho) pathways. All these pathways triggered cells’ proliferation, differentiation, survival and re-organization of the actin cytoskeleton. Overall, this marine-derived, bioactive peptide has the capability to promote proliferation and could be further explored as a cell-growth-promoting agent for biomedical and bioprocessing applications.

Systemic Efficacy of Sirolimus via the ERBB Signaling Pathway in Breast Cancer

Rapamycin, also known as sirolimus, inhibits the mTOR pathway in complex diseases such as cancer, and its downstream targets are ribosomal S6 kinases (RPS6K). Sirolimus is involved in regulating cell growth and cell survival through roles such as the mediation of epidermal growth factor signaling. However, the systemic efficacy of sirolimus in pathway regulation is unclear. The purpose of this study is to determine systemic drug efficacy using computational methods and drug-induced datasets. We suggest a computational method using gene expression datasets induced by sirolimus and an inverse algorithm that simultaneously identifies parameters referring to gene–gene interactions. We downloaded two sirolimus-induced microarray gene expression datasets and used a computational method to obtain the most enriched pathway, then adopted an inverse algorithm to discover the gene–gene interactions of that pathway. In the results, RPS6KB1 was a target gene of sirolimus and was associated with genes in the pathway. The common gene interactions from two datasets were a hub gene, RPS6KB1, and 10 related genes (AKT3, CBLC, MAP2K7, NRG1/2, PAK3, PIK3CD/G, PRKCG, and SHC3) in the epidermal growth factor (ERBB) signaling pathway.

Comparative Metabolomics and Proteomics Reveal Vibrio parahaemolyticus Targets Hypoxia-Related Signaling Pathways of Takifugu obscurus.

Coronavirus disease 2019 (COVID-19) raises the issue of how hypoxia destroys normal physiological function and host immunity against pathogens. However, there are few or no comprehensive omics studies on this effect. From an evolutionary perspective, animals living in complex and changeable marine environments might develop signaling pathways to address bacterial threats under hypoxia. In this study, the ancient genomic model animal Takifugu obscurus and widespread Vibrio parahaemolyticus were utilized to study the effect. T. obscurus was challenged by V. parahaemolyticus or (and) exposed to hypoxia. The effects of hypoxia and infection were identified, and a theoretical model of the host critical signaling pathway in response to hypoxia and infection was defined by methods of comparative metabolomics and proteomics on the entire liver. The changing trends of some differential metabolites and proteins under hypoxia, infection or double stressors were consistent. The model includes transforming growth factor-β1 (TGF-β1), hypoxia-inducible factor-1α (HIF-1α), and epidermal growth factor (EGF) signaling pathways, and the consistent changing trends indicated that the host liver tended toward cell proliferation. Hypoxia and infection caused tissue damage and fibrosis in the portal area of the liver, which may be related to TGF-β1 signal transduction. We propose that LRG (leucine-rich alpha-2-glycoprotein) is widely involved in the transition of the TGF-β1/Smad signaling pathway in response to hypoxia and pathogenic infection in vertebrates as a conserved molecule.

Protective Effects of Ginsenoside Rb1 in Rats with Diabetic Cardiomyopathy

Ginsenosides play an important role in the treatment of diabetes and obesity. Our group predicted that ginsenoside Rb1 combined with insulin would have a protective effect in diabetic cardiomyopathy. Diabetic model was established by high fat feeding combined with intraperitoneal injection of 70 mg/ kg streptozotocin in 8 w old male Sprague-Dawley rats. One rat was sacrificed at 8 w, 12 w and 14 w, respectively. The cardiac function and pathological structure of the myocardium were observed. It was concluded that the model of the diabetic cardiomyopathy group was successful. Rats were randomly divided into 4 groups and treated with different doses for 6 w. During this period, all rats received regular blood from the tail vein, had regular random blood glucose measurements and had regular fasting body weight measurements. After 6 w of intervention, cardiac ultrasonography was performed to evaluate cardiac function in all groups. Blood samples of aorta were collected for biochemical detection and pathological staining, immunohistochemical staining, reverse transcription polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay were taken from heart tissue samples for detection. Compared with the normal group, diabetic cardiomyopathy rats displayed severe hyperglycemia, lower body weight, poorer cardiac performance, cardiac fibrosis and cardiac inflammation. Diabetic cardiomyopathy rats suffered obvious effects from over-activation of the heparin-binding epidermal growth factor pathway. Ginsenoside Rb1 treatment attenuated hyperglycemia, body weight loss and cardiac injury as well as heparin-binding epidermal growth factor activation induced by diabetic cardiomyopathy. Meanwhile, ginsenoside Rb1 had no obvious toxicity or side effects in the heart, liver or kidneys. Ginsenoside Rb1 treatment in diabetic rats can inhibit the over-activated heparin-binding epidermal growth factor signaling pathway, attenuate fibrosis of myocardial tissue and improve cardiac function, and has no obvious toxicity or side effects. It is a potential drug for diabetic heart disease.

Platelets up-Regulate Tumor Cell Programmed Death-Ligand 1 through Epidermal Growth Factor Receptor Signal Transduction

Introduction: Programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) are important immune checkpoint proteins in cancer immunotherapy and targeted therapies against PD-L1 have significantly prolonged many patients' lives. Recently, high baseline platelet to lymphocyte ratio was reported to be associated with decreased patient response rate to immune checkpoint inhibition (ICI) therapies, including anti-PD-L1 therapy, suggesting the potential role of platelets in tumor immunity. Platelets express PD-L1 on their surface, and platelets binding to PD-L1 negative tumor cells can “decorate” tumor cells with PD-L1 and protect against T cell-mediated cytotoxicity. However, whether platelet can affect PD-L1 expression on tumor cells is still unknown.Methods: In this study, we designed platelet-tumor cell co-culture systems to investigate whether direct or indirect exposure to platelets affects tumor cell PD-L1 surface expression. Considering platelets can be artificially activated by commonly used cell culture medium, the co-culture was performed in platelet resuspension buffer (HEPES, NaCl, KCl, MgCl2, NaHCO3, Glucose, pH7.4) supplied with fetal bovine serum and L-glutamine. After 24 hours of co-culture, platelets were washed out and fresh culturing medium was added to tumor cells and cultured for another 24 hours. At the end of the experiments, tumor cells were harvested and the PD-L1 expression analyzed by flow cytometry and RT-qPCR.Results and discussion: Here we report that direct co-culture of platelets with either breast cancer cell line MDA-MB-468 or lung cancer cell line A549 increased tumor cell PD-L1 surface expression by up-regulating PD-L1 transcription. This platelet-induced tumor cell PD-L1 up-regulation can be partly reduced by pre-treating platelets with antiplatelet agents such as aspirin and ticagrelor, suggesting platelet activation contributes to platelet induced tumor cell PD-L1 up-regulation. The up-regulation of tumor cell PD-L1 by platelets was not due to abundant platelet cytokines such as C-C Motif Chemokine Ligand 5 (CCL5) and C-X-C motif chemokine 5 (CXCL5). However, both an epidermal growth factor (EGF) neutralizing antibody and cetuximab (EGFR neutralizing monoclonal antibody) decreased the platelet-induced increase in tumor cell PD-L1, suggesting that platelets initiate tumor cell PD-L1 transcription through the EGF signaling pathway. Our data indicate a novel function of platelets in tumor immunity and warrant further investigation to determine if targeting platelets offers a novel adjuvant approach to improve ICI therapy. DisclosuresItaliano: Sierra Oncology: Consultancy; PlateletBio: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Carrick Therapeutics: Consultancy.

Functional requirements of protein kinases and phosphatases in the development of the Drosophila melanogaster wing.

Protein kinases and phosphatases constitute a large family of conserved enzymes that control a variety of biological processes by regulating the phosphorylation state of target proteins. They play fundamental regulatory roles during cell cycle progression and signaling, among other key aspects of multicellular development. The complement of protein kinases and phosphatases includes approximately 326 members in Drosophila, and they have been the subject of several functional screens searching for novel components of signaling pathways and regulators of cell division and survival. These approaches have been carried out mostly in cell cultures using RNA interference to evaluate the contribution of each protein in different functional assays and have contributed significantly to assign specific roles to the corresponding genes. In this work, we describe the results of an evaluation of the Drosophila complement of kinases and phosphatases using the wing as a system to identify their functional requirements in vivo. We also describe the results of several modifying screens aiming to identify among the set of protein kinases and phosphatases additional components or regulators of the activities of the epidermal growth factor and insulin receptors signaling pathways.

Role of calcium in hormone-independent and -resistant breast cancer.

Approximately one-third of estrogen receptor (ER) positive breast tumors fail to respond to or become resistant to hormonal therapy. Although the mechanisms responsible for hormone resistance are not completely understood, resistance is associated with alterations in ERα; overexpression of proteins that interact with the receptor; and hormone-independent activation of the receptor by growth factor signal transduction pathways. Our previous studies show that in estrogen dependent breast cancer cells, activation of the epidermal growth factor signaling pathway increases intracellular calcium which binds to and activates ERα through sites in the ligand-binding domain of the receptor and that treatment with extracellular calcium increases the concentration of intracellular calcium which activates ERα and induces hormone-independent cell growth. The present study asked whether overexpression of calcium channels contributes to the hormone-independent and -resistant phenotype of breast cancer cells and whether clinically used calcium channel blockers reverse hormone independence and resistance. The results show that hormone-independent and -resistant cells overexpress calcium channels, have high concentrations of intracellular calcium, overexpress estrogen responsive genes and, as expected, grow in the absence of estradiol and that treatment with calcium channel blockers decreased the concentration of intracellular calcium, the expression of estrogen responsive genes and cell growth. More importantly, in hormone-resistant cells, treatment that combined a calcium channel blocker with an antiestrogen reversed resistance to the antiestrogen.

Characterization of the Intramolecular Interactions and Regulatory Mechanisms of the Scaffold Protein Tks4.

The scaffold protein Tks4 is a member of the p47phox-related organizer superfamily. It plays a key role in cell motility by being essential for the formation of podosomes and invadopodia. In addition, Tks4 is involved in the epidermal growth factor (EGF) signaling pathway, in which EGF induces the translocation of Tks4 from the cytoplasm to the plasma membrane. The evolutionarily-related protein p47phox and Tks4 share many similarities in their N-terminal region: a phosphoinositide-binding PX domain is followed by two SH3 domains (so called “tandem SH3”) and a proline-rich region (PRR). In p47phox, the PRR is followed by a relatively short, disordered C-terminal tail region containing multiple phosphorylation sites. These play a key role in the regulation of the protein. In Tks4, the PRR is followed by a third and a fourth SH3 domain connected by a long (~420 residues) unstructured region. In p47phox, the tandem SH3 domain binds the PRR while the first SH3 domain interacts with the PX domain, thereby preventing its binding to the membrane. Based on the conserved structural features of p47phox and Tks4 and the fact that an intramolecular interaction between the third SH3 and the PX domains of Tks4 has already been reported, we hypothesized that Tks4 is similarly regulated by autoinhibition. In this study, we showed, via fluorescence-based titrations, MST, ITC, and SAXS measurements, that the tandem SH3 domain of Tks4 binds the PRR and that the PX domain interacts with the third SH3 domain. We also investigated a phosphomimicking Thr-to-Glu point mutation in the PRR as a possible regulator of intramolecular interactions. Phosphatidylinositol-3-phosphate (PtdIns(3)P) was identified as the main binding partner of the PX domain via lipid-binding assays. In truncated Tks4 fragments, the presence of the tandem SH3, together with the PRR, reduced PtdIns(3)P binding, while the presence of the third SH3 domain led to complete inhibition.

The Polymorphisms of Epidermal Growth Factor-driven Signaling and Cancer Pathogenesis

Background: Epidermal growth factor (EGF) is a stimulating protein for cell proliferation and differentiation. An amplification of its signaling pathway has been frequently reported in numerous malignant tumors. Specific polymorphisms of the genes encoding proteins involved in this cellular pathway may constitute risk factors for carcinogenesis. The aim of this study was to identify the most relevant polymorphisms of EGF and their signaling pathways and their relation to carcinogenesis.
 Methods: The study included 40 full-text articles published between January 2010 and May 2020, extracted from PubMed, Scopus, Web of Science, and Science Direct databases in May 2020, using the following keywords: EGF OR epidermal growth factor AND polymorphism AND cancer OR neoplasia OR tumor.
 Results: We identified relevant polymorphisms of the EGF signaling pathway that were involved in the development and progression of hepatocellular carcinoma, esophageal cancer, gastric cancer, colorectal cancer, glioma, lung cancer, breast cancer, cervical cancer, and head and neck cancer. Rs4444903 variants have been widely studied and the association with numerous tumors has been confirmed by multiple studies. Other frequently investigated polymorphisms are –191C/A and –216G>T.
 Conclusion: The polymorphisms of EGF signaling pathway have been widely studied in connection to various malignancies. Some predisposing variants are common in different forms of cancer. These polymorphisms might be general risk factors for carcinogenesis.

Hexameric procyanidins inhibit colorectal cancer cell growth through redox regulation of the epidermal growth factor signaling pathway

Hexameric procyanidins inhibit colorectal cancer cell growth through redox regulation of the epidermal growth factor signaling pathway

Blocking core fucosylation of epidermal growth factor (EGF) receptor prevents peritoneal fibrosis progression

Objective Peritoneal fibrosis (PF) ultimately causes ultrafiltration failure and peritoneal dialysis (PD) termination, but there are few effective therapies for it. Core fucosylation, which is catalyzed by α1,6-fucosyltransferase (Fut8) in mammals, may play a crucial role in PF development. This study aims to assess the effects of inhibiting core fucosylation of epidermal growth factor (EGF) receptor on PF rats. Methods PF rats (established by 4.25% glucose dialysate) were treated with either an adenovirus-Fut8 short hairpin RNA (Fut8shRNA) or adenovirus-control. Masson’s staining and net ultrafiltration were performed at week six. Fut8 level and core fucosylation of EGF receptor and collagen I in the peritoneal membrane were assessed, and EGF signaling was detected, including signal transducer and activator of transcription 3 (STAT3), nuclear factor kappa B (NF-κB) and their phosphorylation. Monocyte chemoattractant protein-1 (MCP-1) in peritoneal effluent was examined. Results Fut8 was upregulated in PF rats but decreased after Fut8shRNA treatment. EGF and EGF receptor expression was upregulated in PF rats, while core fucosylation of EGF receptor decreased after Fut8shRNA treatment. Masson’s staining results showed an increase in peritoneal thickness in PF rats but a decrease after Fut8shRNA treatment. Fut8shRNA treatment increased net ultrafiltration, reduced the expression of collagen I and MCP-1 compared to PF rats. Fut8shRNA treatment suppressed phosphorylation of STAT3 and NF-κB in the peritoneal membrane of PF rats. Conclusions Fut8shRNA treatment ameliorated the fibrotic changes in PF rats. A potential mechanism may be that Fut8shRNA treatment inactivated EGF signaling pathway by suppressing the phosphorylation of STAT3 and NF-κB.

Hexameric procyanidins inhibit colorectal cancer cell growth through both redox and non-redox regulation of the epidermal growth factor signaling pathway

Dietary proanthocyanidins (PAC) consumption is associated with a decreased risk for colorectal cancer (CRC). Dysregulation of the epidermal growth factor (EGF) receptor (EGFR) signaling pathway is frequent in human cancers, including CRC. We previously showed that hexameric PAC (Hex) exert anti-proliferative and pro-apoptotic actions in human CRC cells. This work investigated if Hex could exert anti-CRC effects through its capacity to regulate the EGFR pathway. In proliferating Caco-2 cells, Hex acted attenuating EGF-induced EGFR dimerization and NADPH oxidase-dependent phosphorylation at Tyr 1068, decreasing EGFR location at lipid rafts, and inhibiting the downstream activation of pro-proliferative and anti-apoptotic pathways, i.e. Raf/MEK/ERK1/2 and PI3K/Akt. Hex also promoted EGFR internalization both in the absence and presence of EGF. While Hex decreased EGFR phosphorylation at Tyr 1068, it increased EGFR Tyr 1045 phosphorylation. The latter provides a docking site for the ubiquitin ligase c-Cbl and promotes EGFR degradation by lysosomes. Importantly, Hex acted synergistically with the EGFR-targeted chemotherapeutic drug Erlotinib, both in their capacity to decrease EGFR phosphorylation and inhibit cell growth. Thus, dietary PAC could exert anti-CRC actions by modulating, through both redox- and non-redox-regulated mechanisms, the EGFR pro-oncogenic signaling pathway. Additionally, Hex could also potentiate the actions of EGFR-targeted drugs.

RNF11 at the Crossroads of Protein Ubiquitination.

RNF11 (Ring Finger Protein 11) is a 154 amino-acid long protein that contains a RING-H2 domain, whose sequence has remained substantially unchanged throughout vertebrate evolution. RNF11 has drawn attention as a modulator of protein degradation by HECT E3 ligases. Indeed, the large number of substrates that are regulated by HECT ligases, such as ITCH, SMURF1/2, WWP1/2, and NEDD4, and their role in turning off the signaling by ubiquitin-mediated degradation, candidates RNF11 as the master regulator of a plethora of signaling pathways. Starting from the analysis of the primary sequence motifs and from the list of RNF11 protein partners, we summarize the evidence implicating RNF11 as an important player in modulating ubiquitin-regulated processes that are involved in transforming growth factor beta (TGF-β), nuclear factor-κB (NF-κB), and Epidermal Growth Factor (EGF) signaling pathways. This connection appears to be particularly significant, since RNF11 is overexpressed in several tumors, even though its role as tumor growth inhibitor or promoter is still controversial. The review highlights the different facets and peculiarities of this unconventional small RING-E3 ligase and its implication in tumorigenesis, invasion, neuroinflammation, and cancer metastasis.