Epidermal Growth Factor Receptor Phosphorylation Research Articles

Functional Distinctions of Endometrial Cancer-Associated Mutations in the Fibroblast Growth Factor Receptor 2 Gene.

Functional analysis of somatic mutations in tumorigenesis facilitates the development and optimization of personalized therapy for cancer patients. The fibroblast growth factor receptor 2 (FGFR2) gene is frequently mutated in endometrial cancer (EC), but the functional implications of FGFR2 mutations in cancer development remain largely unexplored. In this study, we introduced a reliable and readily deployable screening method to investigate the effects of FGFR2 mutations. We demonstrated that distinct mutations in FGFR2 can lead to differential downstream consequences, specifically affecting a disintegrin- and metalloprotease 17 (ADAM17)-dependent shedding of the epidermal growth factor receptor (EGFR) ligand heparin-binding EGF-like growth factor (HB-EGF) and phosphorylation of mitogen-activated protein kinases (MAPKs). Furthermore, we showed that the distribution of mutations within the FGFR2 gene can influence their oncogenic effects. Together, these findings provide important insights into the complex nature of FGFR2 mutations and their potential implications for EC. By unraveling the distinct effects of different mutations, our study contributes to the identification of personalized treatment strategies for patients with FGFR2-mutated cancers. This knowledge has the potential to guide the development of targeted therapies that specifically address the underlying molecular alterations associated with FGFR2 mutations, ultimately improving patient outcomes in EC and potentially other cancer types characterized by FGFR2 mutations.

Bispecific antibody CD73xEGFR more selectively inhibits the CD73/adenosine immune checkpoint on cancer cells and concurrently counteracts pro-oncogenic activities of CD73 and EGFR

BackgroundCD73 is an ecto-enzyme that is involved in the conversion of pro-inflammatory extracellular ATP (eATP) excreted by cancer cells under stress to anti-inflammatory adenosine (ADO). A broad variety of solid...

A homologous and molecular dual-targeted biomimetic nanocarrier for EGFR-related non-small cell lung cancer therapy.

The abnormal activation of epidermal growth factor receptor (EGFR) drives the development of non-small cell lung cancer (NSCLC). The EGFR-targeting tyrosine kinase inhibitor osimertinib is frequently used to clinically treat NSCLC and exhibits marked efficacy in patients with NSCLC who have an EGFR mutation. However, free osimertinib administration exhibits an inadequate response in vivo, with only ∼3% patients demonstrating a complete clinical response. Consequently, we designed a biomimetic nanoparticle (CMNP@Osi) comprising a polymeric nanoparticle core and tumor cell-derived membrane-coated shell that combines membrane-mediated homologous and molecular targeting for targeted drug delivery, thereby supporting a dual-target strategy for enhancing osimertinib efficacy. After intravenous injection, CMNP@Osi accumulates at tumor sites and displays enhanced uptake into cancer cells based on homologous targeting. Osimertinib is subsequently released into the cytoplasm, where it suppresses the phosphorylation of upstream EGFR and the downstream AKT signaling pathway and inhibits the proliferation of NSCLC cells. Thus, this dual-targeting strategy using a biomimetic nanocarrier can enhance molecular-targeted drug delivery and improve clinical efficacy.

Downregulation of cellular retinoic acid binding protein 1 fosters epithelial-mesenchymal transition in thyroid cancer.

Cellular retinoic acid binding protein 1 (CRABP1) participates in the regulation of retinoid signaling. Previous studies showed conflicting results regarding the role of CRABP1 in tumor biology, including protumorigenic and tumor-suppressive effects in different types of cancer. Our bioinformatics analyses suggested that CRABP1 expression was downregulated in thyroid cancer. Ectopic expression of CRABP1 in thyroid cancer cells suppressed migratory and invasive activity without affecting cell growth or cell cycle distribution. In transformed normal thyroid follicular epithelial cells, silencing of CRABP1 expression increased invasiveness. Additionally, CRABP1 overexpression was associated with downregulation of the mesenchymal phenotype. Kinase phosphorylation profiling indicated that CRABP1 overexpression was accompanied by a decrease in phosphorylation of epidermal growth factor (EGF) receptor and downstream phosphorylation of Akt, STAT3, and FAK, which were reversed by exogenous EGF treatment. Immunohistochemical analysis of our tissue microarrays revealed an inverse association between CRABP1 expression and disease stage of differentiated thyroid cancer. Taken together, our results suggest that CRABP1 expression is aberrantly lost in thyroid cancer, and this downregulation promotes the epithelial-mesenchymal transition at least partly through modulating EGF receptor signaling.

Promoting the activity of a receptor tyrosine phosphatase with a novel pH-responsive transmembrane agonist inhibits cancer-associated phenotypes.

Cell signaling by receptor protein tyrosine kinases (RTKs) is tightly controlled by the counterbalancing actions of receptor protein tyrosine phosphatases (RPTPs). Due to their role in attenuating the signal-initiating potency of RTKs, RPTPs have long been viewed as therapeutic targets. However, the development of activators of RPTPs has remained limited. We previously reported that the homodimerization of a representative member of the RPTP family (protein tyrosine phosphatase receptor J or PTPRJ) is regulated by specific transmembrane (TM) residues. Disrupting this interaction by single point mutations promotes PTPRJ access to its RTK substrates (e.g., EGFR and FLT3), reduces RTK's phosphorylation and downstream signaling, and ultimately antagonizes RTK-driven cell phenotypes. Here, we designed and tested a series of first-in-class pH-responsive TM peptide agonists of PTPRJ that are soluble in aqueous solution but insert as a helical TM domain in lipid membranes when the pH is lowered to match that of the acidic microenvironment of tumors. The most promising peptide reduced EGFR's phosphorylation and inhibited cancer cell EGFR-driven migration and proliferation, similar to the PTPRJ's TM point mutations. Developing tumor-selective and TM-targeting peptide binders of critical RPTPs could afford a potentially transformative approach to studying RPTP's selectivity mechanism without requiring less specific inhibitors and represent a novel class of therapeutics against RTK-driven cancers.

TSPAN8 regulates EGFR/AKT pathway to enhance metastasis in gastric cancer.

Tetraspanin 8 (TSPAN8), a transmembrane glycoprotein, is implicated in various pathological conditions including human malignancies. However, the roles and underlying mechanisms of TSPAN8 in promoting gastric cancer(GC)progression are yet to be fully understood. Our study found that TSPAN8 expression was significantly elevated in GC tissues. We also observed a positive correlation between high TSPAN8 expression and various clinicopathological characteristics of GC, including tumor differentiation, invasion depth, lymph node metastasis, and clinical stage. Moreover, the elevated TSPAN8 expression was indicative of poor prognosis. Functionally, we observed that knockdown of TSPAN8 significantly attenuated while overexpression of TSPAN8 promoted GC cell migration and invasion. In vivo experiments, knockdown of TSPAN8 suppressed lung metastasis in nude mice. We further explored the underlying mechanisms of TSPAN8 and found that it regulated EGFR expression in GC cells by accelerating phosphorylation of EGFR and AKT. Our study reveals that TSPAN8 plays a significant role in promoting tumor metastasis by activating the EGFR/AKT pathway, indicating that it may serve as a promising therapeutic target of gastric cancer.

SUMOylation of AnxA6 facilitates EGFR-PKCα complex formation to suppress epithelial cancer growth

BackgroundThe Annexin A6 (AnxA6) protein is known to inhibit the epidermal growth factor receptor (EGFR)-extracellular signal regulated kinase (ERK)1/2 signaling upon EGF stimulation. While the biochemical mechanism of AnxA6 inactivating phosphorylation of EGFR and ERK1/2 is not completely explored in cancer cells.MethodsCells were transiently co-transfected with pFlag-AnxA6, pHA-UBC9 and pHis-SUMO1 plasmids to enrich the SUMOylated AnxA6 by immunoprecipitation, and the modification level of AnxA6 by SUMO1 was detected by Western blot against SUMO1 antibody. The SUMOylation level of AnxA6 was compared in response to chemical SUMOylation inhibitor treatment. AnxA6 SUMOylation sites were further identified by LC–MS/MS and amino acid site mutation validation. AnxA6 gene was silenced through AnxA6 targeting shRNA-containing pLKO.1 lentiviral transfection in HeLa cells, while AnxA6 gene was over-expressed within the Lenti-Vector carrying AnxA6 or mutant AnxA6K299R plasmid in A431 cells using lentiviral infections. Moreover, the mutant plasmid pGFP-EGFRT790M/L858R was constructed to test AnxA6 regulation on EGFR mutation-induced signal transduction. Moreover, cell proliferation, migration, and gefitinib chemotherapy sensitivity were evaluated in HeLa and A431 cells under AnxA6 konckdown or AnxA6 overexpression by CCK8, colony form and wound healing assays. And tumorigenicity in vivo was measured in epithelial cancer cells-xenografted nude mouse model.ResultsAnxA6 was obviously modified by SUMO1 conjugation within Lys (K) residues, and the K299 was one key SUMOylation site of AnxA6 in epithelial cancer cells. Compared to the wild type AnxA6, AnxA6 knockdown and its SUMO site mutant AnxA6K299R showed less suppression of dephosphorylation of EGFR-ERK1/2 under EGF stimulation. The SUMOylated AnxA6 was prone to bind EGFR in response to EGF inducement, which facilitated EGFR-PKCα complex formation to decrease the EGF-induced phosphorylation of EGFR-ERK1/2 and cyclin D1 expression. Similarly, AnxA6 SUMOylation inhibited dephosphorylation of the mutant EGFR, thereby impeding EGFR mutation-involved signal transduction. Moreover, AnxA6 knockdown or the K299 mutant AnxA6K299R conferred AnxA6 inability to suppress tumor progression, resulting in drug resistance to gefitinib in epithelial cancer cells. And in epithelial cancer cells-xenografted nude mouse model, both the weight and size of tumors derived from AnxA6 knockdown or AnxA6K299R mutation-expressing cells were much greater than that of AnxA6-expressing cells.ConclusionsBesides EGFR gene mutation, protein SUMOylation modification of EGFR-binding protein AnxA6 also functions pivotal roles in mediating epithelial cancer cell growth and gefitinib drug effect.4V8MbH9D2-V-dxkGbe_YjXVideo

LHPP suppresses proliferation, migration, and invasion in hepatocellular carcinoma and pancreatic cancer by inhibiting EGFR signaling pathway.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) has been reported to be a new tumor suppressor with a significant inhibitory effect in various cancers. Although LHPP has been repeatedly shown to inhibit the progression of various tumors by inhibiting the phosphorylation of AKT, up to now, the studies on the function and mechanism of LHPP in tumors are insufficient. In this study, LHPP expression was found to be downregulated in both hepatocellular carcinoma (HCC) and pancreatic cancer (PC). Here, we found that LHPP could bind to epidermal growth factor receptor (EGFR) and inhibit its phosphorylation, which thereby inhibited the activation of EGFR downstream pathways ERK, AKT, and STAT3, and then weakening the ability to proliferate, invade, and migrate in HCC and PC. This paper showed a new physiological function of LHPP in inhibiting phosphorylation of EGFR and its potential anti-tumor mechanism and indicated that LHPP was a potential therapeutic target for HCC and PC.

Knockdown of PTK7 Reduces the Oncogenic Potential of Breast Cancer Cells by Impeding Receptor Tyrosine Kinase Signaling.

Protein tyrosine kinase 7 (PTK7), a catalytically defective receptor tyrosine kinase (RTK), is often upregulated in various cancers. This study aimed to validate PTK7 as a target for breast cancer (BC) and investigate its oncogenic signaling mechanism. BC tissue analysis showed significantly elevated PTK7 mRNA levels, especially in refractory triple-negative breast cancer (TNBC) tissues, compared with normal controls. Similarly, BC cell lines exhibited increased PTK7 expression. Knockdown of PTK7 inhibited the proliferation of T-47D and MCF-7 hormone-receptor-positive BC cell-lines and of HCC1187, MDA-MB-231, MDA-MB-436, and MDA-MB-453 TNBC cells. PTK7 knockdown also inhibited the adhesion, migration, and invasion of MDA-MB-231, MDA-MB-436, and MDA-MB-453 cells, and reduced the phosphorylation levels of crucial oncogenic regulators including extracellular signal-regulated kinase (ERK), Akt, and focal adhesion kinase (FAK). Furthermore, PTK7 interacts with fibroblast growth factor receptor 1 (FGFR1) and epidermal growth factor receptor (EGFR) expressed in MDA-MB-231 cells. Knockdown of PTK7 decreased the growth-factor-induced phosphorylation of FGFR1 and EGFR in MDA-MB-231 cells, indicating its association with RTK activation. In conclusion, PTK7 plays a significant role in oncogenic signal transduction by enhancing FGFR1 and EGFR activation, influencing BC tumorigenesis and metastasis. Hence, PTK7 represents a potential candidate for targeted BC therapy, including TNBC.

Tissue kallikrein-related peptidase8 accentuates cardiac fibrosis after myocardial ischemia-reperfusion injury via regulation of cardiac fibroblasts

AimsTissue kallikrein-related peptidase8 (KLK8) has been found to mitigate acute myocardial ischemia-reperfusion (IR) injury. However, the effect of KLK8 on cardiac remodeling in response to IR injury has not been determined. Materials and methodsKLK8 overexpressing transgenic rat (KLK8-TG) was used as the animal model. IR injury was induced by ligating the left anterior descending coronary artery for 1 h and subsequent reperfusion. The functional and morphological changes of the heart were examined 14 days after the injury. Neonatal rat cardiac fibroblasts (CFs) were used to investigate the molecular mechanisms in vitro. Key findingsKLK8 overexpression enhanced cardiac diastolic dysfunction, fibrosis, and hypertrophy after IR injury, indicating that KLK8 accentuated cardiac remodeling in response to IR injury. Moreover, KLK8 overexpression increased epidermal growth factor (EGF) release and promoted the phosphorylation of EGF receptor (EGFR) and ERK1/2 in the heart after IR injury. It was interesting to find that both EGFR antagonist (AG 1478) and MEK inhibitor (PD98059) attenuated the KLK8-induced proliferation and activation of CFs in vitro, indicating that EGFR signaling might mediate the pro-fibrotic action of KLK8. SignificanceKLK8 plays a crucial role in cardiac remodeling after myocardial infarction. KLK8 accentuates cardiac fibrosis after IR injury, possibly mediated by EGFR signaling in CFs.

Exploring the possible mechanism(s) underlying the nephroprotective effect of Zhenwu Decoction in diabetic kidney disease: An integrated analysis

BackgroundDiabetic kidney disease (DKD) is one of the major chronic microvascular complications of diabetes and the main cause of end-stage renal failure. Zhenwu Decoction (ZWD), an ancient classic herbal formula in Chinese medicine, has been clinically used for the treatment of kidney disease in China for many years. However, there is currently limited research investigating the application of ZWD in the treatment of DKD and the underlying chemical and biochemical mechanisms involved. Therefore, in the present study, we aimed to identify active components in ZWD and unravel the possible mechanism(s) of action for ZWD in treating DKD. MethodsThe protective effect of ZWD against DKD was evaluated utilizing an in vitro model of diabetic renal proximal tubulopathy. The major chemical components from ZWD were identified by LC-MS/MS. Drug targets were predicted by submitting the SMILES (Simplified Molecular Input Line Entry System) of the compounds to SEA (Similarity Ensemble Approach) search server and SwissTargetPrediction. The differentially expressed genes (DEGs) of the disease were collected and integrated from GeneCards. The constructions of “Compounds-potential targets interaction” (CTI) network and Protein-Protein Interaction (PPI) network, as well as topology analysis were conducted by Cytoscape. Gene Ontology (GO) enrichment and Metacore pathway enrichment analysis were also performed. Lastly, molecular docking and experimental studies were adopted to validate the core target and identify an active component(s) of ZWD. ResultsWe demonstrated that the ZWD extract could significantly rescue the palmitic acid (PA) and high glucose-induced apoptotic cell death in HK-2 cells, and the cytoprotection was accompanied by decreases in the extent of reactive oxygen species (ROS) production, mitochondrial membrane depolarization and ATP depletion. Fifty-seven compounds in the aqueous extract of ZWD were identified by LC-MS. The results of PPI analysis showed that top hub genes involved epidermal growth factor receptor (EGFR), Signal Transducer and Activator of Transcription 3 (STAT3), Serine/Threonine Kinase 1 (AKT1), Vascular Endothelial Growth Factor A (VEGFA) and Fibroblast Growth Factor 2 (FGF2). Pathway enrichment analysis revealed the involvement of S1P1 receptor signaling and EGFR pathways. The results of molecular docking analysis showed that albiflorin has a high binding affinity to EGFR. Albiflorin could also exert protective effects in an HK-2 cell model of DKD, which may be related to the inhibition of the high glucose/high lipid-induced EGFR and Akt phosphorylation. ConclusionZWD has been shown to be effective in ameliorating cell death in an experimental model of DKD. The beneficial effect of ZWD against DKD was associated with the interactions between the active ingredients and the hub genes, such as EGFR, STAT3, AKT1, and VEGF-A. Albiflorin may be one of the active components responsible for the nephroprotective effect in ZWD.

Sharing Weal and Woe: A Commentary on “Gasdermin E Regulates the Stability and Activation of EGFR in Human Non-Small Cell Lung Cancer Cells”

Abnormal activation of epidermal growth factor receptor (EGFR) promotes the development of Non-Small Cell Lung Cancer Cells (NSCLC). Chemoresistance to tyrosine kinase inhibitors (TKIs), which is elicited by EGFR mutations, is a key challenge for NSCLC treatment. In the present study, we demonstrate a critical role of gasdermin E (GSDME), an important protein for pyroptosis, in the maintenance of EGFR stability and activation. We found that GSDME depletion suppressed the EGFR-mediated proliferation of NSCLC cells in vitro. GSDME knockdown downregulated the protein level of CCND1 and inhibited the phosphorylation of ERK1/2 in NSCLC cells. Mechanistically, both GSDME-FL and GSDME-N fragment physically interacted with EGFR. GSDME interacted with cytoplasmic fragment (CT) of EGFR. GSDME knockdown inhibited EGFR dimerization and phosphorylation at tyrosine 1173 (EGFRY1173), which could activate ERK1/2. GSDME knockdown promoted EGFR degradation and phosphorylation at tyrosine 1045 (EGFRY1045). Importantly, GSDME-FL increased the stability of EGFR, while the GSDME-N fragment induced EGFR degradation. Together, our results demonstrate that the GSDME-EGFR interaction plays an important role in NSCLC development, reveal a previously unrecognized link between GSDME and EGFR stability and offer new insight into cancer pathogenesis.

Maintenance of airway epithelial barrier integrity via the inhibition of AHR/EGFR activation ameliorates chronic obstructive pulmonary disease using effective-component combination

BackgroundAirway epithelial barrier dysfunction is highly related to the pathogenesis of chronic obstructive pulmonary disease (COPD). Effective-component combination (ECC) derived from Bufei Yishen formula (BYF) is an effective treatment regimen for patients with COPD and has previously been found to attenuate COPD and airway epithelial inflammation in rats. PurposeTo determine the mechanism underlying the protective effects of ECC-BYF against the disruption of the airway epithelial barrier in COPD. MethodsThe protective effects of ECC-BYF on the airway epithelial barrier were investigated in a rat COPD model. BEAS-2B epithelial cells were stimulated with cigarette smoke extract (CSE) to determine the direct effects of ECC-BYF on epithelial barrier function and aryl hydrocarbon receptor (AHR)/ epidermal growth factor receptor (EGFR) signaling. ResultsThe results revealed that ECC-BYF attenuated COPD in rats and maintained the airway epithelial barrier by upregulating the expression of apical junction proteins, including occludin (OCC), zonula occludens (ZO)-1, and E-cadherin (E-cad). In BEAS-2B cells, ECC-BYF decreased permeability, increased transepithelial electrical resistance, and prevented the decrease in OCC, ZO-1, and E-cad expression induced by CSE exposure. In addition, transcriptomics and network analysis revealed that the protective effects of ECC-BYF may be related to multiple signaling pathways, including ErbB, AHR, and PI3K–Akt–mTOR pathways. ECC-BYF treatment suppressed the protein levels of p-EGFR and p-ERK1/2 and mRNA levels of CYP1A1 in CSE-exposed BEAS-2B cells as well as the protein levels of p-EGFR, p-ERK1/2, and CYP1A1 in the lungs of rats with COPD. In BEAS-2B cells, the AHR agonist FICZ weakened the protective effect of ECC-BYF on the epithelial barrier by suppressing the increase in ZO-1 and OCC expression induced by ECC-BYF and preventing the inhibitory effects of ECC-BYF on EGFR phosphorylation. ConclusionsThis is the first study to demonstrate the protective effect of ECC-BYF on airway epithelial barrier function. The underlying mechanism may be associated with the suppression of the AHR/EGFR pathway to promote apical junction protein adhesion.

Fraxin represses NF-κB pathway via inhibiting the activation of epidermal growth factor receptor to ameliorate diabetic renal tubulointerstitial fibrosis

Renal tubulointerstitial fibrosis (RIF), featured by epithelial-to-mesenchymal-transition (EMT) of renal tubular epithelial cells and collagen deposition in the renal interstitial region, is the main pathological change of diabetic nephropathy (DN). Fraxin, the main active component of Fraxinus rhynchophylla Hance with anti-inflammatory activity, has been demonstrated to ameliorate glomerulosclerosis. However, the regulatory role of Fraxin on diabetic RIF remains unclear. In this study, we investigated the renal protective benefits of Fraxin against diabetic RIF and elucidated its mechanisms. In vitro, Fraxin inhibited the abnormal expression of EMT-related markers and proinflammatory cytokines, improved cellular morphology, and subsequently reduced the extracellular matrix (ECM) production in high glucose (HG)-induced NRK-52E cells. In vivo, Fraxin effectively ameliorated renal function, inhibited the abnormal expression of EMT-related markers and proinflammatory cytokines, and reduced ECM deposition in renal tubule interstitium in db/db mice. Notably, Fraxin could directly bind to epidermal growth factor receptor (EGFR), which contributed to the inhibition of EGFR phosphorylation and counteracted the activation of c-Src/NF-κB pathway, eventually ameliorating RIF. Thus, Fraxin may be a potential drug candidate for treating DN.

Stanniocalcin 1 promotes lung metastasis of breast cancer by enhancing EGFR–ERK–S100A4 signaling

Lung metastasis is the leading cause of breast cancer-related death. The tumor microenvironment contributes to the metastatic colonization of tumor cells in the lungs. Tumor secretory factors are important mediators for the adaptation of cancer cells to foreign microenvironments. Here, we report that tumor-secreted stanniocalcin 1 (STC1) promotes the pulmonary metastasis of breast cancer by enhancing the invasiveness of tumor cells and promoting angiogenesis and lung fibroblast activation in the metastatic microenvironment. The results show that STC1 modifies the metastatic microenvironment through its autocrine action on breast cancer cells. Specifically, STC1 upregulates the expression of S100 calcium-binding protein A4 (S100A4) by facilitating the phosphorylation of EGFR and ERK signaling in breast cancer cells. S100A4 mediates the effect of STC1 on angiogenesis and lung fibroblasts. Importantly, S100A4 knockdown diminishes STC1-induced lung metastasis of breast cancer. Moreover, activated JNK signaling upregulates STC1 expression in breast cancer cells with lung-tropism. Overall, our findings reveal that STC1 plays important role in breast cancer lung metastasis.

Spray-dried microparticles of encapsulated gefitinib for slow-release localized treatment of periodontal disease

Periodontal disease (PD) can be prevented by local or systemic application of epidermal growth factor receptor inhibitors (EGFRIs) that stabilize αvβ6 integrin levels in the periodontal tissue, leading to an increase in the expression of anti-inflammatory cytokines, such as transforming growth factor-β1. Systemic EGFRIs have side effects and, therefore, local treatment of PD applied into the periodontal pockets would be preferrable. Thus, we have developed slow-release three-layered microparticles of gefitinib, a commercially available EGFRI. A combination of different polymers [cellulose acetate butyrate (CAB), Poly (D, L-lactide-co-glycolide) (PLGA) and ethyl cellulose (EC)] and sugars [D-mannose, D-mannitol and D-(+)-trehalose dihydrate] were used for the encapsulation. The optimal formulation was composed of CAB, EC, PLGA, mannose and gefitinib (0.59, 0.24, 0.09, 1, and 0.005 mg/ml, respectively; labeled CEP-gef), and created microparticles of 5.7 ± 2.3 µm in diameter, encapsulation efficiency of 99.98%, and a release rate of more than 300 h. A suspension of this microparticle formulation blocked EGFR phosphorylation and restored αvβ6 integrin levels in oral epithelial cells, while the respective control microparticles showed no effect.

Probenecid ameliorates testosterone-induced benign prostatic hyperplasia: Implications of PGE-2 on ADAM-17/EGFR/ERK1/2 signaling cascade.

Benign prostatic hyperplasia (BPH) is one of the most prevalent clinical disorders in the elderly. Probenecid (Prob) is a well-known FDA-approved therapy for gout owing to its uricosuric effect. The present study evaluated the use of Prob for BPH as a COX-2 inhibitor. Prob (100 and 200 mg/kg) was intraperitoneally injected into male Wistar rats daily for 3 weeks. In the second week, testosterone (3 mg/kg) was subcutaneously injected to induce BPH. Compared with BPH-induced rats, Prob treatment reduced prostate weight and index and improved histopathological architecture. The protease activity of ADAM-17/TACE and its ligands (TGF-α and TNF-α) were regulated by prob, which in turn abolished EGFR phosphorylation, and several inflammatory mediators (COX-2, PGE2, NF-κB (p65), and IL-6) were suppressed. By reducing the nuclear import of extracellular regulated kinase protein 1/2 (ERK1/2), Prob helped re-establish the usual equilibrium between antiapoptotic proteins like Bcl-2 and cyclin D1 and proapoptotic proteins like Bax. All of these data point to Prob as a promising treatment for BPH because of its ability to inhibit COX-2-syntheiszed PGE2 and control the ADAM-17/TGF-α-induced EGFR/ERK1/2 signaling cascade. These findings might help to repurpose Prob for the treatment of BPH.

Sustaining the Activation of EGFR Signal by Inflammatory Cytokine IL17A Prompts Cell Proliferation and EGFR-TKI Resistance in Lung Cancer

Non-small-cell lung cancer (NSCLC) is a typical inflammation-associated cancer, and lung adenocarcinoma (LUAD) is the most common pathological subtype. Epidermal growth factor (EGF) receptor (EGFR) mutations are the most common driver mutations of LUAD, and they have been identified as important therapeutic targets by EGFR-tyrosine kinase inhibitors (TKIs). The proinflammatory cytokine, interleukin (IL)-17A, and IL-17A-producing cells were reported to be elevated in the tumor microenvironment and peripheral blood of NSCLC patients and to be correlated with tumor progression and poor prognoses. However, the pathophysiological role of IL-17A in NSCLC remains unclear, although some studies suggested its involvement in cancer cell invasion and metastasis. Herein, we observed that expressions of IL-17A and its receptor, IL-17 receptor C (IL-17RC), were elevated in LUAD tissues and were correlated with poor survival in different lung cancer cohorts. In LUAD cells with mutant EGFR, the IL-17A/IL-17RC axis was shown to enhance phosphorylation of EGFR and Met, thereby promoting proliferation and resistance to EGFR-TKIs such as afatinib. In LUAD cells with wild-type (WT) EGFR, we found that the IL-17A/IL-17RC axis enhanced EGF-induced EGFR activation and cell proliferation through causing impairment of EGF-induced EGFR lysosomal degradation. Collectively, our results indicated diverse impacts of the IL-17A/IL-17RC axis on EGFR activation in LUAD cells with WT and mutant EGFR and suggested that developing therapeutic strategies against IL-17A/IL-17RC would be valuable for LUAD treatment.

Cetuximab enhances radiosensitivity of esophageal squamous cell carcinoma cells by G2/M cycle arrest and DNA repair delay through inhibiting p-EGFR and p-ERK.

Although radiotherapy has improved local control in esophageal squamous cell carcinoma (ESCC), a considerable number of patients still experience relapse due to resistance. In this study, we aimed to evaluate the effects of cetuximab on radiosensitivity in two ESCC cell lines (ECA109 and TE-13) and to investigate their underlying mechanisms. Cells were pretreated with or without cetuximab before irradiation. The MTT assay and clonogenic survival assay were performed to evaluate cell viability and radiosensitivity. Flow cytometry was performed to analyze cell cycle distribution and apoptosis. The γH2AX foci were counted to determine cellular DNA-repairing capacity via immunofluorescence assay. The phosphorylation of key molecules involved in the epidermal growth factor receptor (EGFR) signaling pathway and DNA double-strand break (DSB) repair were measured by western blot. Cetuximab alone was not sufficient to suppress cell viability, but significantly enhanced radiation-induced inhibition of clonogenic survival in ECA109 and TE-13. The radiation sensitivity enhancement ratio (SER) was 1.341 and 1.237 for ECA109 and TE-13, respectively. ESCC cells treated with cetuximab were arrested at the G2/M phase in response to radiation. No significant increase in apoptotic rate was observed in irradiated cells that were treated with cetuximab. The average number of γH2AX foci increased in the combination group (cetuximab and radiation). Cetuximab suppressed phosphorylation of EGFR and downstream ERK, but had no significant effect on AKT. These results indicate the potential for use of cetuximab as an effective radiosensitizer in ESCC. Cetuximab promotes G2/M cycle arrest and reduces DSB repair, as well as inhibiting EGFR and downstream ERK pathways in ESCC.

Design, synthesis and evaluation of new pyrimidine derivatives as EGFRC797S tyrosine kinase inhibitors

The clinical use of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in the treatment of non-small cell lung cancer was limited by the drug resistance caused by EGFRC797S mutation. Therefore, in order to overcome the drug resistance, we designed and synthesized a series of 2-aminopyrimidine derivatives as EGFRC797S-TKIs. Among these compounds, compounds A5 and A13 showed significant anti-proliferative activity against the KC-0116 (EGFRdel19/T790M/C797S) cell line with high selectivity. A5 inhibited EGFR phosphorylation and induced apoptosis of KC-0116 cell, arrested KC-0116 cell at G2/M phase. Molecular docking results showed that A5 and brigatinib bind to EGFR in a similar pattern. In addition to forming two important hydrogen bonds with Met793 residue, A5 also formed a hydrogen bond with Lys745 residues, which may play an important role for the potent inhibitory activity against EGFRdel19/T790M/C797S. Based on these results, A5 turned out to be effective reversible EGFRC797S-TKIs which can be further developed.