Therapeutic strategies targeting the epidermal growth factor receptor signaling pathway in metastatic colorectal cancer

More than 1.9 million new colorectal cancer(CRC)cases and 935000 deaths were estimated to occur worldwide in 2020,representing about one in ten cancer cases and deaths.Overall,colorectal ranks third in incidence,but second in mortality.More than half of the patients are in advanced stages at diagnosis.Treatment options are complex because of the heterogeneity of the patient population,including different molecular subtypes.Treatments have included conventional fluorouracil-based chemotherapy,targeted therapy,immunotherapy,etc.In recent years,with the development of genetic testing technology,more and more targeted drugs have been applied to the treatment of CRC,which has further prolonged the survival of metastatic CRC patients.

Effects of (-)-Epigallocatechin gallate on some protein factors involved in the epidermal growth factor receptor signaling pathway

（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resulting in the control of unwanted cell proliferation. The epidermal growth factor receptor （EGFR） signaling pathway is one of the most important pathways that regulates growth, survival,proliferation and differentiation in mammalian cells. This review addresses the effects of EGCG on some protein factors involved in the EGFR signaling pathway in a direct or indirect manner. Based on our understanding of the interaction between EGCG and these factors, and based on their structures, EGCG could be used as a lead compound for designing and synthesizing novel drugs with significant biological activity.

BIRC3 induces the phosphoinositide 3-kinase-Akt pathway activation to promote trastuzumab resistance in human epidermal growth factor receptor 2-positive gastric cancer

BACKGROUND Trastuzumab-targeted therapy is currently the standard of care for advanced human epidermal growth factor receptor 2(HER2)-positive gastric cancer.However,the emergence of resistance to trastuzumab poses significant challenges.AIM To identify the key genes associated with trastuzumab resistance.These results provide a basis for the development of interventions to address drug resistance and improve patient outcomes.METHODS High-throughput sequencing and bioinformatics were used to identify the differentially expressed pivotal gene BIRC3 and delineate its potential function and pathway regulation.Tumor samples were collected from patients with HER2-positive gastric cancer to evaluate the correlation between BIRC3 expression and trastuzumab resistance.We established gastric cancer cell lines with both highly expressed and suppressed levels of BIRC3,followed by comprehensive in vitro and in vivo experiments to confirm the involvement of BIRC3 in trastuzumab resistance and to elucidate its underlying mechanisms.RESULTS In patients with HER2-positive gastric cancer,there is a significant correlation between elevated BIRC3 expression in tumor tissues and higher T stage,tumor node metastasis stage,as well as poor overall survival and progressionfree survival.BIRC3 is highly expressed in trastuzumab-resistant gastric cancer cell lines,where it inhibits tumor cell apoptosis and enhances trastuzumab resistance by promoting the phosphorylation and activation of the phosphoinositide 3-kinase-Akt(PI3K-AKT)pathway in HER2-positive gastric cancer cells,both in vivo and in vitro.CONCLUSION This study revealed a robust association between high BIRC3 expression and an unfavorable prognosis in patients with HER2-positive gastric cancer.Thus,the high expression of BIRC3 stimulated PI3K-AKT phosphorylation and activation,stimulating the proliferation of HER2-positive tumor cells and suppressing apoptosis,ultimately leading to trastuzumab resistance.

PRaG 3.0 therapy for human epidermal growth factor receptor 2-positive metastatic pancreatic ductal adenocarcinoma:A case report

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly fatal disease with limited effective treatment especially after first-line chemotherapy.The human epidermal growth factor receptor 2(HER-2)immunohistochemistry(IHC)positive is associated with more aggressive clinical behavior and shorter overall survival in PDAC.CASE SUMMARY We present a case of multiple metastatic PDAC with IHC mismatch repair proficient but HER-2 IHC weakly positive at diagnosis that didn’t have tumor regression after first-line nab-paclitaxel plus gemcitabine and PD-1 inhibitor treatment.A novel combination therapy PRaG 3.0 of RC48(HER2-antibody-drug conjugate),radio-therapy,PD-1 inhibitor,granulocyte-macrophage colony-stimulating factor and interleukin-2 was then applied as second-line therapy and the patient had confirmed good partial response with progress-free-survival of 6.5 months and overall survival of 14.2 month.She had not developed any grade 2 or above treatment-related adverse events at any point.Percentage of peripheral CD8^(+) Temra and CD4^(+) Temra were increased during first two activation cycles of PRaG 3.0 treatment containing radiotherapy but deceased to the baseline during the maintenance cycles containing no radiotherapy.CONCLUSION PRaG 3.0 might be a novel strategy for HER2-positive metastatic PDAC patients who failed from previous first-line approach and even PD-1 immunotherapy but needs more data in prospective trials.

Efficacy and safety of dacomitinib as first-line treatment for advanced non-small cell lung cancer patients with epidermal growth factor receptor 21L858R mutation:A multicenter,case-series study in China

Objective:To provide real-world evidence for the application of first-line dacomitinib treatment for epidermal growth factor receptor(EGFR)21L858R mutant non-small cell lung cancer(NSCLC)patients in China and to explore the factors influencing the efficacy and safety.Methods:A longitudinal,consecutive case-series,multicenter study with mixed prospective and retrospective data was conducted.The primary endpoint was progression-free survival(PFS),and the secondary endpoints included duration of treatment(DOT),overall survival(OS),objective response rate(ORR),disease control rate(DCR)and safety.Results:A total of 155 EGFR 21L858R mutant patients treated with first-line dacomitinib were included.The median follow-up time for these patients was 20.4 months.Among 134 patients with evaluable lesions,the ORR was 70.9%and the DCR was 96.3%.The median PFS was 16.3[95%confidence interval(95%CI),13.7−18.9]months.Multivariate Cox regression analysis suggested that the baseline brain metastasis(BM)status[with vs.without BM:hazard ratio(HR),1.331;95%CI,0.720−2.458;P=0.361]and initial doses(45 mg vs.30 mg:HR,0.837;95%CI,0.427−1.641;P=0.604)did not significantly affect the median PFS.The median DOT was 21.0(95%CI,17.5−24.6)months and the median OS was not reached.Genetic tests were performed in 64 patients after progression,among whom 29(45.3%)patients developed the EGFR 20T790M mutation.In addition,among the 46 patients who discontinued dacomitinib treatment after progression,31(67.4%)patients received subsequent third-generation EGFR-tyrosine kinase inhibitors.The most common grade 3−4 adverse events were rash(10.4%),diarrhea(9.1%),stomatitis(7.1%)and paronychia(4.5%).The incidence of grade 3−4 rash was significantly higher in the 45 mg group than that in the 30 mg group(21.9%vs.7.5%,P=0.042).Conclusions:First-line dacomitinib treatment demonstrated promising efficacy and tolerable adverse events among EGFR 21L858R mutant NSCLC patients in China.

Inetetamab combined with S-1 and oxaliplatin as first-line treatment for human epidermal growth factor receptor 2-positive gastric cancer

BACKGROUND Patients with human epidermal growth factor receptor 2(HER2)-positive advanced gastric cancer have poor outcomes.Trastuzumab combined with chemotherapy is the first-line standard treatment for HER2-positive advanced gastric cancer.Inetetamab is a novel anti-HER2 drug,and its efficacy and safety in gastric cancer have not yet been reported.AIM To evaluate the efficacy and safety of the S-1 plus oxaliplatin(SOX)regimen combined with inetetamab as a first-line treatment for HER2-positive advanced gastric cancer.METHODS Thirty-eight patients with HER2-positive advanced gastric cancer or gastroeso-phageal junction adenocarcinoma were randomly divided into two groups:One group received inetetamab combined with the SOX regimen,and the other group received trastuzumab combined with the SOX regimen.After 4-6 cycles,patients with stable disease received maintenance therapy.The primary endpoints were progression-free survival(PFS)and overall survival(OS),and the secondary endpoints were the objective response rate,disease control rate,and adverse events(AEs).RESULTS Thirty-seven patients completed the trial,with 18 patients in the inetetamab group and 19 patients in the trastuzumab group.In the inetetamab group,the median PFS was 8.5 months,whereas it was 7.3 months in the trastuzumab group(P=0.046);this difference was significant.The median OS in the inetetamab group vs the trastuzumab group was 15.4 months vs 14.3 months(P=0.33),and the objective response rate was 50%vs 42%(P=0.63),respectively;these differences were not significant.Common AEs included leukopenia,thrombocytopenia,nausea,and vomiting.The incidence rates of grade≥3 AEs were 56%in the inetetamab group and 47%in the trastuzumab group(P=0.63),with no significant difference.CONCLUSION In the first-line treatment of HER2-positive advanced gastric cancer,inetetamab and trastuzumab showed comparable efficacy.The inetetamab group showed superior PFS,and both groups had good safety.

Advances in targeted therapy for human epidermal growth factor receptor 2 positive in advanced gastric cancer

Emerging therapeutic methods represented by targeted therapy are effective supplements to traditional first-line chemoradiotherapy resistance.Human epidermal growth factor receptor 2(HER2)is one of the most important targets in targeted therapy for gastric cancer.Trastuzumab combined with chemotherapy has been used as the first-line treatment for advanced gastric cancer.The safety and efficacy of pertuzumab and margetuximab in the treatment of gastric cancer have been verified.However,monoclonal antibodies,due to their large molecular weight,inability to penetrate the blood-brain barrier,and drug resistance,lead to decreased therapeutic efficacy,so it is necessary to explore the efficacy of other HER2-targeting therapies in gastric cancer.Small-molecule tyrosine kinase inhibitors,such as lapatinib and pyrrotinib,have the advantages of small molecular weight,penetrating the blood-brain barrier and high oral bioavailability,and are expected to become the drugs of choice for perioperative treatment and neoadjuvant therapy of gastric cancer after validation by large-scale clinical trials in the future.Antibo-drug conjugate,such as T-DM1 and T-DXd,can overcome the resistance of monoclonal antibodies despite their different mechanisms of tumor killing,and are a supplement for the treatment of patients who have failed the treatment of monoclonal antibodies such as trastuzumab.Therefore,after more detailed stratification of gastric cancer patients,various gastric cancer drugs targeting HER2 are expected to play a more significant role.

Concomitant epidermal growth factor receptor mutation/c-ros oncogene 1 rearrangement in non-small cell lung cancer: A case report

BACKGROUND Epidermal growth factor receptor(EGFR)mutation and c-ros oncogene 1(ROS1)rearrangement are key genetic alterations and predictive tumor markers for non-small cell lung cancer(NSCLC)and are typically considered to be mutually exc-lusive.EGFR/ROS1 co-mutation is a rare event,and the standard treatment appr-oach for such cases is still equivocal.CASE SUMMARY Herein,we report the case of a 64-year-old woman diagnosed with lung adenocar-cinoma,with concomitant EGFR L858R mutation and ROS1 rearrangement.The patient received two cycles of chemotherapy after surgery,but the disease prog-ressed.Following 1-month treatment with gefitinib,the disease progressed again.However,after switching to crizotinib,the lesion became stable.Currently,crizotinib has been administered for over 53 months with a remarkable treatment effect.CONCLUSION The efficacy of EGFR tyrosine kinase inhibitors and crizotinib was vastly different in this NSCLC patient with EGFR/ROS1 co-mutation.This report will aid future treatment of such patients.

Human epidermal growth factor receptor 2 expression level and combined positive score can evaluate efficacy of advanced gastric cancer

BACKGROUND Although treatment options for gastric cancer(GC)continue to advance,the overall prognosis for patients with GC remains poor.At present,the predictors of treatment efficacy remain controversial except for high microsatellite instability.AIM To develop methods to identify groups of patients with GC who would benefit the most from receiving the combination of a programmed cell death protein 1(PD-1)inhibitor and chemotherapy.METHODS We acquired data from 63 patients with human epidermal growth factor receptor 2(HER2)-negative GC with a histological diagnosis of GC at the Cancer Hospital,Chinese Academy of Medical Sciences between November 2020 and October 2022.All of the patients screened received a PD-1 inhibitor combined with chemotherapy as the first-line treatment.RESULTS As of July 1,2023,the objective response rate was 61.9%,and the disease control rate was 96.8%.The median progression-free survival(mPFS)for all patients was 6.3 months.The median overall survival was not achieved.Survival analysis showed that patients with a combined positive score(CPS)≥1 exhibited an extended trend in progression-free survival(PFS)when compared to patients with a CPS of 0 after receiving a PD-1 inhibitor combined with oxaliplatin and tegafur as the first-line treatment.PFS exhibited a trend for prolongation as the expression level of HER2 increased.Based on PFS,we divided patients into two groups:A treatment group with excellent efficacy and a treatment group with poor efficacy.The mPFS of the excellent efficacy group was 8 months,with a mPFS of 9.1 months after excluding a cohort of patients who received interrupted therapy due to surgery.The mPFS was 4.5 months in patients in the group with poor efficacy who did not receive surgery.Using good/poor efficacy as the endpoint of our study,univariate analysis revealed that both CPS score(P=0.004)and HER2 expression level(P=0.015)were both factors that exerted significant influence on the efficacy of treatment the combination of a PD-1 inhibitor and chemotherapy in patients with advanced GC(AGC).Finally,multivariate analysis confirmed that CPS score was a significant influencing factor.CONCLUSION CPS score and HER2 expression both impacted the efficacy of immunotherapy combined with chemotherapy in AGC patients who were non-positive for HER2.

Oxidative stress affects retinal pigment epithelial cell survival through epidermal growth factor receptor/AKT signaling pathway

AIM：To investigate the cross-talk between oxidative stress and the epidermal growth factor receptor（EGFR）/AKT signaling pathway in retinal pigment epithelial（ RPE） cells.METHODS：Human RPE cell lines（ARPE-19 cell） were treated with different doses of epidermal growth factor（EGF） and hydrogen peroxide（H2O2）.Cell viability was determined by a methyl thiazolyl tetrazolium assay.Cell proliferation was examined by a bromodeoxyuridine（Brd U） incorporation assay.EGFR/AKT signaling was detected by Western blot.EGFR localization was also detected by immunofluorescence.In addition,EGFR/AKT signaling was intervened upon by EGFR inhibitor（erlotinib）,PI3 K inhibitor（A66） and AKT inhibitor（MK-2206）,respectively.H2O2-induced oxidative stress was blocked by antioxidant N-acetylcysteine（NAC）.RESULTS：EGF treatment increased ARPE-19 cell viabili ty and proliferation through inducing phosphorylation of EGFR and AKT.H2O2 inhibited ARPE-19 cell viability and proliferation and also suppressed EGF-stimulated increase of RPE cell viability and proliferation by affecting the EGFR/AKT signaling pathway.EGFR inhibitor erlotinib blocked EGF-induced phosphorylation of EGFR and AKT,while A66 and MK-2206 only blocked EGF-induced phosphorylation of AKT.EGF-induced phosphorylation andendocytosis of EGFR were also affected by H2O2 treatment.In addition,antioxidant NAC attenuated H2O2-induced inhibition of ARPE-19 cell viability through all eviating reduction of EGFR,and phosphorylated and total AKT proteins.CONCLUSION：Oxidative stress affects RPE cell viability and proliferation through interfering with the EGFR/AKT signaling pathway.The EGFR/AKT signaling pathway may be an important target in oxidative stress-induced RPE cell dysfunction.

Signaling pathways involved in the inhibition of epidermal growth factor receptor by erlotinib in hepatocellular cancer

AIM： To examine the underlying mechanisms of erlotinib-induced growth inhibition in hepatocellular carcinoma （HCC）. METHODS： Erlotinib-induced alterations in gene expression were evaluated using cDNA array technology; changes in protein expression and/or protein activation due to erlotinib treatment as well as IGF-1-induced EGFR transactivation were investigated using Western blotting. RESULTS： Erlotinib treatment inhibited the mitogen activated protein （MAP）-kinase pathway and signal transducer of activation and transcription （STAT）- mediated signaling which led to an altered expression of apoptosis and cell cycle regulating genes as demonstrated by cDNA array technology. Overexpression of proapoptotic factors like caspases and gadds associated with a down-regulation of antiapoptotic factors like Bcl-2, Bcl-XL or jun D accounted for erlotinib＇s potency to induce apoptosis. Downregulation of cell cycle regulators promoting the G1/S-transition and overexpression of cyclin-dependent kinase inhibitors and gadds contributed to the induction of a G1/G0-arrest in response to erlotinib. Furthermore, we displayed the transactivation of EGFR-mediated signaling by the IGF-1-receptor and showed erlotinib＇s inhibitory effects on the receptor-receptor cross talk. CONCLUSION： Our study sheds light on the understanding of the mechanisms of action of EGFR-TK- inhibition in HCC-cells and thus might facilitate the design of combination therapies that act additively or synergistically. Moreover, our data on the pathways responding to erlotinib treatment could be helpful in predicting the responsiveness of tumors to EGFR-TKIs in the future.

Alterations in the human epidermal growth factor receptor 2-phosphatidylinositol 3-kinase-v-Akt pathway in gastric cancer

AIM:To investigate human epidermal growth factor receptor 2(HER2)-phosphatidylinositol 3-kinase(PI3K)-vAkt murine thymoma viral oncogene homolog signaling pathway.METHODS:We analyzed 231 formalin-fixed,paraffinembedded gastric cancer tissue specimens from Japanese patients who had undergone surgical treatment.The patients' age,sex,tumor location,depth of invasion,pathological type,lymph node metastasis,and pathological stage were determined by a review of the medical records.Expression of HER2 was analyzed by immunohistochemistry(IHC) using the HercepTest TM kit.Standard criteria for HER2 positivity(0,1+,2+,and 3+) were used.Tumors that scored 3+ were considered HER2-positive.Expression of phospho Akt(pAkt) was also analyzed by IHC.Tumors were considered pAkt-positive when the percentage of positive tumor cells was 10% or more.PI3K,catalytic,alpha polypeptide(PIK3CA) mutations in exons 1,9 and 20 were analyzed by pyrosequencing.Epstein-Barr virus(EBV) infection was analyzed by in situ hybridization targeting EBV-encoded small RNA(EBER) with an EBER-RNA probe.Microsatellite instability(MSI) was analyzed by polymerase chain reaction using the mononucleotide markers BAT25 and BAT26.RESULTS:HER2 expression levels of 0,1+,2+ and 3+ were found in 167(72%),32(14%),12(5%) and 20(8.7%) samples,respectively.HER2 overexpression(IHC 3+) significantly correlated with intestinal histological type(15/20 vs 98 /205,P = 0.05).PIK3CA mutations were present in 20 cases(8.7%) and significantly correlated with MSI(10/20 vs 9/211,P < 0.01).The mutation frequency was high(21%) in T4 cancers and very low(6%) in T2 cancers.Mutations in exons 1,9 and 20 were detected in 5(2%),9(4%) and 7(3%) cases,respectively.Two new types of PIK3CA mutation,R88Q and R108H,were found in exon1.All PIK3CA mutations were heterozygous missense singlebase substitutions,the most common being H1047R(6/20,30%) in exon20.Eighteen cancers(8%) were EBV-positive and this positivity significantly correlated with a diffuse histological type(13/18 vs 93/198,P = 0.04).There were 7 cases of lymphoepithelioma-like carcinomas(LELC) and 6 of those cases were EBV-positive(percent/EBV:6/18,33%;percent/all LELC:6/7,86%).pAkt expression was positive in 119(53%) cases but showed no correlation with clinicopathological characteristics.pAkt expression was significantly correlated with HER2 overexpression(16/20 vs 103/211,P < 0.01) but not with PIK3CA mutations(12/20 vs 107/211,P = 0.37) or EBV infection(8/18 vs 103/211,P = 0.69).The frequency of pAkt expression was higher in cancers with exon20 mutations(100%) than in those with exon1(40%) or exon9(56%) mutations.One case showed both HER2 overexpression and EBV infection and 3 cases showed both PIK3CA mutations and EBV infection.However,no cases showed both PIK3CA mutations and HER2 overexpression.One EBVpositive cancer with PIK3CA mutation(H1047R) was MSI-positive.Three of these 4 cases were positive for pAkt expression.In survival analysis,pAkt expression significantly correlated with a poor prognosis(hazard ratio 1.75;95%CI:1.12-2.80,P = 0.02).CONCLUSION:HER2 expression,PIK3CA mutations and EBV infection in gastric cancer were characterized.pAkt expression significantly correlates with HER2 expression and with a poor prognosis.

Epidermal growth factor receptor and K-Ras in non-small cell lung cancer-molecular pathways involved and targeted therapies

Lung cancer is currently the leading cause of cancer death in Western nations.Non-small cell lung cancer(NSCLC)represents 80%of all lung cancers,and adenocarcinoma is the predominant histological type.Despite the intensive research carried out on this field and therapeutic advances,the overall prognosis of these patients remains unsatisfactory,with a 5-year overall survival rate of less than 15%.Nowadays,pharmacogenetics and pharmacogenomics represent the key to successful treatment.Recent studies suggest the existence of two distinct molecular pathways in the carcinogenesis of lung adenocarcinoma:one associated with smoking and activation of the K-Ras oncogene and the other not associated with smoking and activation of the epidermal growth factor receptor(EGFR).The K-ras mutation is mainly responsible for primary resistance to new molecules which inhibit tyrosine kinase EGFR(erlotinib and gefitinib)and most of the EGFR mutations are responsible for increased tumor sensitivity to these drugs.This article aims to conduct a systematic review of the literature regarding the molecular pathways involving the EGFR,K-Ras and EGFR targeted therapies in NSCLC tumor behavior.

Oncogenic fingerprint of epidermal growth factor receptor pathway and emerging epidermal growth factor receptor blockade resistance in colorectal cancer

Epidermal growth factor receptor(EGFR) has been an attractive target for treatment of epithelial cancers, including colorectal cancer(CRC). Evidence from clinical trials indicates that cetuximab and panitumumab(antiEGFR monoclonal antibodies) have clinical activity in patients with metastatic CRC. The discovery of intrinsic EGFR blockade resistance in Kirsten RAS(KRAS)-mutant patients led to the restriction of anti-EGFR antibodies to KRAS wild-type patients by Food and Drug Administration and European Medicine Agency. Studies have since focused on the evaluation of biomarkers to identify appropriate patient populations that may benefit from EGFR blockade. Accumulating evidence suggests that patients with mutations in EGFR downstream signaling pathways including KRAS, BRAF, PIK3CA and PTEN could be intrinsically resistant to EGFR blockade. Recent whole genome studies also suggest that dynamic alterations in signaling pathways downstream of EGFR leads to distinct oncogenic signatures and subclones which might have some impact on emerging resistance in KRAS wild-type patients. While anti-EGFR monoclonal antibodies have a clear potential in the management of a subset of patients with metastatic CRC, further studies are warranted to uncover exact mechanisms related to acquired resistance to EGFR blockade.

Nexus of signaling and endocytosis in oncogenesis driven by non-small cell lung cancer-associated epidermal growth factor receptor mutants

Epidermal growth factor receptor(EGFR) controls a wide range of cellular processes, and aberrant EGFR signaling as a result of receptor overexpression and/or mutation occurs in many types of cancer. Tumor cells in non-small cell lung cancer(NSCLC) patients that harbor EGFR kinase domain mutations exhibit oncogene addiction to mutant EGFR, which confers high sensitivity to tyrosine kinase inhibitors(TKIs). As patients invariably develop resistance to TKIs, it is important to delineate the cell biological basis of mutant EGFR-induced cellular transformation since components of these pathways can serve as alternate therapeutic targets to preempt or overcome resistance. NSCLC-associated EGFR mutants are constitutively-active and induce ligandindependent transformation in nonmalignant cell lines. Emerging data suggest that a number of factors are critical for the mutant EGFR-dependent tumorigenicity, and bypassing the effects of TKIs on these pathways promotes drug resistance. For example, activation of downstream pathways such as Akt, Erk, STAT3 and Src is critical for mutant EGFR-mediated biological processes. It is now well-established that the potency and spatiotemporal features of cellular signaling by receptor tyrosine kinases such as EGFR, as well as the specific pathways activated, is determined by the nature of endocytic traffic pathways through which the active receptors traverse. Recent evidence indicates that NSCLCassociated mutant EGFRs exhibit altered endocytic trafficking and they exhibit reduced Cbl ubiquitin ligasemediated lysosomal downregulation. More recent work has shown that mutant EGFRs undergo ligand-independent traffic into the endocytic recycling compartment, a behavior that plays a key role in Src pathway activation and oncogenesis. These studies are beginning to delineate the close nexus between signaling and endocytic traffic of EGFR mutants as a key driver of oncogenicprocesses. Therefore, in this review, we will discuss the links between mutant EGFR signaling and endocytic properties, and introduce potential mechanisms by which altered endocytic properties of mutant EGFRs may alter signaling and vice versa as well as their implications for NSCLC therapy.

Inhibition of epidermal growth factor receptor signaling protects human malignant glioma cells from hypoxia - induced cell death

Epidermal growth factor receptor(EGFR)signaling has become an importanttarget for drug development becauseEGFR signaling enhances tumor cell proliferation,migration,and invasion and inhibits apoptosis.However,theresults of clinical trials using EGFR inhibitors in patients with solid tumors have been disappointing.Here,wereport a protective effect of the EGFR inhibitors AG1478 and PD153035 against cell death induced by acute hy-poxia,which contrasts with their proapoptotic effects under normoxia.Under hypoxic conditions,both agents re-

Forkhead Box q1 promotes invasion and metastasis in colorectal cancer by activating the epidermal growth factor receptor pathway

BACKGROUND Colorectal cancer(CRC)is an extremely malignant tumor with a high mortality rate.Little is known about the mechanism by which forkhead Box q1(FOXQ1)causes CRC invasion and metastasis through the epidermal growth factor receptor(EGFR)pathway.AIM To illuminate the mechanism by which FOXQ1 promotes the invasion and metastasis of CRC by activating the heparin binding epidermal growth factor(HB-EGF)/EGFR pathway.METHODS We investigated the differential expression and prognosis of FOXQ1 and HB-EGF in CRC using the Gene Expression Profiling Interactive Analysis(GEPIA)website(http://gepia.cancer-pku.cn/index.html).Quantitative real-time polymerase chain reaction(qRT-PCR)and Western blotting were used to detect the expression of FOXQ1 and HB-EGF in cell lines and tissues,and we constructed a stable lowexpressing FOXQ1 cell line and verified it with the above method.The expression changes of membrane-bound HB-EGF(proHB-EGF)and soluble HB-EGF(sHB-EGF)in the lowexpressing FOXQ1 cell line were detected by flow cytometry and ELISA.Western blotting was used to detect changes in the expression levels of HB-EGF and EGFR pathway-related downstream genes when exogenous recombinant human HB-EGF was added to FOXQ1 knockdown cells.Proliferation experiments,transwell migration experiments,and scratch experiments were carried out to determine the mechanism by which FOXQ1 activates the EGFR signaling pathway through HB-EGF,and then to evaluate the clinical relevance of FOXQ1 and HB-EGF.RESULTS GEPIA showed that the expression of FOXQ1 in CRC tissues was relatively high and was related to a lower overall survival rate.PCR array results showed that FOXQ1 is related to the HB-EGF and EGFR pathways.Knockdown of FOXQ1 suppressed the expression of HB-EGF,and led to a decrease in EGFR and its downstream genes AKT,RAF,KRAS expression levels.After knockdown of FOXQ1 in CRC cell lines,cell proliferation,migration and invasion were attenuated.Adding HB-EGF restored the migration and invasion ability of CRC,but not the cell proliferation ability.Kaplan–Meier survival analysis results showed that the combination of FOXQ1 and HB-EGF may serve to predict CRC survival.CONCLUSION Based on these collective data,we propose that FOXQ1 promotes the invasion and metastasis of CRC via the HB-EGF/EGFR pathway.

Epidermal growth factor receptor:a key manipulator in molecular pathways of malignant glioma

The epidermal growth factor receptor （EGFR） is a member of the ErbB/EGFR family, including EGFR/Herl, ErbB2/Her2, ErbB-3/Her3, and ErbB-4/Her4. EGFR exerts its effects through the receptor tyrosine kinase phosphorylation and activation of important downstream signaling pathways in normal and neoplastic cells, mainly the Ras GTPase/MAP kinase （MAPK）, STAT3, and phosphatidylinositide 3 kinase-AKT pathways. EGFR deregulation is common in malignant glioma, especially primary glioblastoma, and exists in three forms： gene overexpression （amplification）, autocrine effects of EGFR activation, and activating receptor mutation （EGFRvlII）. However, some EGFR abnormalities have also been found in low-grade gliomas, including the nuclear localization of EGFR, expression in the microfoci of anaplastic transformation, and association with neovascularization in the mesenchyma of the glioma, which suggests that some unknown EGFR-related mechanisms are possibly responsible for its central role in the initiation and progression of malignant glioma. Uncovering these mechanisms will have potential value in the development of radio- therapy, chemotherapy, and EGFR-targeted therapy for glioma.

Inhibition of EGFR attenuates EGF-induced activation of retinal pigment epithelium cell via EGFR/AKT signaling pathway

AIM:To explore the effect of epidermal growth factor receptor(EGFR)inhibition by erlotinib and EGFR siRNA on epidermal growth factor(EGF)-induced activation of retinal pigment epithelium(RPE)cells.METHODS:Human RPE cell line(ARPE-19 cells)was activated by 100 ng/mL EGF.Erlotinib and EGFR siRNA were used to intervene EGF treatment.Cellular viability,proliferation,and migration were detected by methyl thiazolyl tetrazolium(MTT)assay,bromodeoxyuridine(BrdU)staining assay and wound healing assay,respectively.EGFR/protein kinase B(AKT)pathway proteins and N-cadherin,α-smooth muscle actin(α-SMA),and vimentin were tested by Western blot assay.EGFR was also determined by immunofluorescence staining.RESULTS:EGF treatment for 24h induced a significant increase of ARPE-19 cells’viability,proliferation and migration,phosphorylation of EGFR/AKT proteins,and decreased total EGFR expression.Erlotinib suppressed ARPE-19 cells’viability,proliferation and migration through down regulating total EGFR and AKT protein expressions.Erlotinib also inhibited EGF-induced an increase of proliferative and migrative ability in ARPE-19 cells and clearly suppressed EGF-induced EGFR/AKT proteins phosphorylation and decreased expression of N-cadherin,α-SMA,and vimentin proteins.Similarly,EGFR inhibition by EGFR siRNA significantly affected EGF-induced an increase of cell proliferation,viability,and migration,phosphorylation of EGFR/AKT proteins,and up-regulation of N-cadherin,α-SMA,and vimentin proteins.CONCLUSION:Erlotinib and EGFR-knockdown suppress EGF-induced cell viability,proliferation,and migration via EGFR/AKT pathway in RPE cells.EGFR inhibition may be a possible therapeutic approach for proliferative vitreoretinopathy(PVR).

Knockdown of HE4 suppresses tumor growth and invasiveness in lung adenocarcinoma through regulation of EGFR signaling

It has been shown that the high expression of human epididymis protein 4(HE4)in most lung cancers is related to the poor prognosis of patients,but the mechanism of pathological transformation of HE4 in lung cancer is still unclear.The current study is expected to clarify the function and mechanism of HE4 in the occurrence and metastasis of lung adenocarcinoma(LUAD).Immunoblotting evaluated HE4 expression in lung cancer cell lines and biopsies,and through analysis of The Cancer Genome Atlas(TCGA)dataset.Frequent HE4 overexpression was demonstrated in LUAD,but not in lung squamous cell carcinoma(LUSC),indicating that HE4 can serve as a biomarker to distinguish between LUAD and LUSC.HE4 knockdown significantly inhibited cell growth,colony formation,wound healing,and invasion,and blocked the G1-phase of the cell cycle in LUAD cell lines through inactivation of the EGFR signaling downstream including PI3K/AKT/mTOR and RAF/MAPK pathways.The first-line EGFR inhibitor gefitinib and HE4 shRNA had no synergistic inhibitory effect on the growth of lung adenocarcinoma cells,while the third-line EGFR inhibitor osimertinib showed additive anti-proliferative effects.Moreover,we provided evidence that HE4 regulated EGFR expression by transcription regulation and protein interaction in LUAD.Our findings suggest that HE4 positively modulates the EGFR signaling pathway to promote growth and invasiveness in LUAD and highlight that targeting HE4 could be a novel strategy for LUAD treatment.