Amphiregulin Switches Progenitor Cell Fate for Lineage Commitment During Gastric Mucosal Regeneration

BACKGROUND & AIMS

Isthmic progenitors, tissue-specific stem cells in the stomach corpus, maintain mucosal homeostasis by balancing between proliferation and differentiation to gastric epithelial lineages. The progenitor cells rapidly adopt an active state in response to mucosal injury. However, it remains unclear how the isthmic progenitor cell niche is controlled during the regeneration of damaged epithelium.

METHODS

We recapitulated tissue recovery process after acute mucosal injury in the mouse stomach. Bromodeoxyuridine incorporation was used to trace newly generated cells during the injury and recovery phases. To define the epithelial lineage commitment process during recovery, we performed single-cell RNA-sequencing on epithelial cells from the mouse stomachs. We validated the effects of amphiregulin (AREG) on mucosal recovery, using recombinant AREG treatment or AREG-deficient mice.

RESULTS

We determined that an epidermal growth factor receptor ligand, AREG, can control progenitor cell lineage commitment. Based on the identification of lineage-committed subpopulations in the corpus epithelium through single-cell RNA-sequencing and bromodeoxyuridine incorporation, we showed that isthmic progenitors mainly transition into short-lived surface cell lineages but are less frequently committed to long-lived parietal cell lineages in homeostasis. However, mucosal regeneration after damage directs the lineage commitment of isthmic progenitors towards parietal cell lineages. During recovery, AREG treatment promoted repopulation with parietal cells, while suppressing surface cell commitment of progenitors. In contrast, transforming growth factor-α did not alter parietal cell regeneration, but did induce expansion of surface cell populations. AREG deficiency impairs parietal cell regeneration but increases surface cell commitment.

CONCLUSIONS

These data demonstrate that different epidermal growth factor receptor ligands can distinctly regulate isthmic progenitor-driven mucosal regeneration and lineage commitment.

High glucose enhances the aggressiveness of lung adenocarcinoma via activating epidermal growth factor receptor/signal transducer and activator of transcription 3 pathways

Epidemiological studies revealed hyperglycemia as a poor prognostic factor for lung adenocarcinoma with unclear molecular mechanisms. The present study thus aimed to investigate the effects of high glucose on the progression of lung adenocarcinoma and its underlying mechanisms. Lung adenocarcinoma cell lines, A549 and RERF-LC-KJ, were cultured in 5.6 mM glucose (normal glucose; NG) or 25 mM glucose (high glucose; HG) resembling euglycemia and hyperglycemia. Cells were examined for proliferation by the MTT assay, and migration-invasion using Transwell. The expressions of signaling proteins in epidermal growth factor receptor (EGFR) pathways and their downstream targets were investigated using Western blots. The effects of diabetes mellitus (DM) and hyperglycemia on lung adenocarcinoma growth in vivo were studied in streptozotocin-induced diabetic BALB/cAJcl-Nu/Nu mice and their non-diabetic counterparts. High glucose significantly promoted proliferation, migration, and invasion of lung adenocarcinoma cells compared with those in normal glucose (P<0.05). Western blot analyses showed the increased ratio of pEGFR/EGFR in cells cultured in high glucose and subsequently activated the signal transducer and activator of transcription 3 (STAT3). Epithelial-mesenchymal (EMT) markers were also altered in lung adenocarcinoma cells in high glucose conditions, corresponding with increased migration and invasion abilities. Erlotinib, an EGFR inhibitor, significantly reversed high glucose-induced aggressive phenotypes confirming high glucose-enhancing lung adenocarcinoma progression via the activation of EGFR. DM and hyperglycemia also promoted the growth of lung adenocarcinoma xenografts in vivo in which erlotinib significantly suppressed the growth of tumors (P<0.05) suggesting EGFR inhibitor as an effective therapeutic agent for lung adenocarcinoma with DM.

Oxidative stress-mediated EGFR activation by cigarette smoke or heated tobacco aerosol in human primary bronchial epithelial cells from multiple donors

The epidermal growth factor receptor (EGFR) signaling pathway has essential roles in maintaining homeostasis of various tissues by regulating cell proliferation and differentiation. Deregulation of the EGFR signaling pathway is associated with various chronic diseases including chronic obstructive pulmonary disease. Cigarette smoke (CS) is known to activate EGFR, which is linked to chronic obstructive pulmonary disease. The biological sequence from CS exposure to EGFR activation is initiated by oxidative stress caused by intracellular reactive oxygen species (ROS) and the depletion of glutathione, which led to EGFR ligand secretion and EGFR activation. We hypothesized that reducing exposure to CS constituents contributes to preventing CS-inducible EGFR activation. Therefore, we examined the aerosol from heated tobacco products (HTPs) because the aerosol contains fewer chemical constituents at lower levels than CS. We exposed primary human bronchial epithelial cells from four donors to the extracts of CS from a 1R6F reference cigarette or HTP aerosol from three in-market products, including our DT3.0a. The biological sequence from ROS to EGFR activation were assessed. CS induced all the tested endpoints although inter-donor differences were observed, whereas HTPs elicited most of the biological events at higher concentrations; however, EGFR phosphorylation was not observed even at five-fold higher concentration than CS. Overall our results indicate that HTPs are less effective than CS to elicit ROS-induced EGFR activation. The reduced-risk potential of HTPs on EGFR-related diseases should be investigated further. In addition, testing with multiple donors is warranted when considering the individual differences in responses of primary cells to stimuli.

Curcumol Exerts Antitumor Effect via Inhibiting EGFR-Akt-Mcl-1 Signaling

Dysfunction of epidermal growth factor receptor (EGFR) signaling plays a critical role in the tumorigenesis of oral squamous cell carcinoma (OSCC). In the present study, the data analysis results of immunohistochemistry and the TCGA database verified that the expression of EGFR is significantly upregulated in OSCC tumor tissues, and depletion of EGFR inhibits the growth of OSCC cells in vitro and in vivo. Moreover, these results showed that the natural compound, curcumol, exhibited a profound antitumor effect on OSCC cells. Western blotting, MTS, and immunofluorescent staining assays indicated that curcumol inhibited cell proliferation and induced intrinsic apoptosis in OSCC cells via downregulating myeloid cell leukemia 1 (Mcl-1). A mechanistic study revealed that curcumol inhibited the EGFR-Akt signal pathway, which activated GSK-3[Formula: see text]-mediated Mcl-1 phosphorylation. Further research showed that curcumol-induced Mcl-1 Ser159 phosphorylation is required to disrupt the interaction between deubiquitinase JOSD1 and Mcl-1 and eventually induce Mcl-1 ubiquitination and degradation. In addition, curcumol administration can effectively inhibit CAL27 and SCC25 xenograft tumor growth and is well-tolerated in vivo. Finally, we demonstrated that Mcl-1 is upregulated and positively correlates with p-EGFR and p-Akt in OSCC tumor tissues. Collectively, the present results provide new insights into the antitumor mechanism of curcumol, identifying it as an attractive therapeutic agent that reduces Mcl-1 expression and inhibits OSCC growth. Targeting EGFR/Akt/Mcl-1 signaling could be a promising option in the clinical treatment of OSCC.

Osimertinib as neoadjuvant therapy in patients with EGFR-mutant resectable stage II-IIIB lung adenocarcinoma (NEOS): A multicenter, single-arm, open-label phase 2b trial

OBJECTIVES

Osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), has been approved for EGFR-mutant non-small-cell lung cancer (NSCLC). We aimed to evaluate the efficacy and safety of neoadjuvant osimertinib in patients with EGFR-mutant resectable locally advanced NSCLC.

MATERIALS AND METHODS

This single-arm, phase 2b trial (ChiCTR1800016948) was conducted at six centers in mainland China. Patients with a measurable stage IIA-IIIB (T3-4 N2) lung adenocarcinoma and EGFR exon 19 and/or 21 mutations were enrolled. The patients were treated with osimertinib 80 mg orally once per day for six weeks, followed by surgical resection. The primary endpoint was the objective response rate (ORR) assessed according to the Response Evaluation Criteria In Solid Tumors version 1.1.

RESULTS

Between October 17, 2018, and June 08, 2021, 88 patients were screened for eligibility. Forty patients were enrolled and treated with neoadjuvant osimertinib therapy. The ORR was 71.1 % (27/38) (95 % confidence interval: 55.2-83.0) in 38 patients who completed the 6-week osimertinib treatment. Thirty-two patients underwent surgery, and 30 (93.8 %) underwent successful R0 resection. Thirty (75.0 %) of 40 patients had treatment-related adverse events during neoadjuvant treatment, and three (7.5 %) had treatment-related adverse events of grade 3. The most common treatment-related adverse events were rash (n = 20 [50 %]), diarrhea (n = 12 [30 %]), and oral ulceration (n = 12 [30 %]).

CONCLUSIONS

The third-generation EGFR TKI osimertinib, with satisfying efficacy and acceptable safety profile, could be a promising neoadjuvant therapy in patients with resectable EGFR-mutant NSCLC.

Quantifying imaging agent binding and dissociation in 3D cancer spheroid tissue culture using paired-agent principles

Binding kinetics play an important role in cancer diagnosis and therapeutics. However, current methods of quantifying binding kinetics fail to consider the three-dimensional environment that drugs and imaging agents experience in biological tissue. In response, a methodology to assay agent binding and dissociation in 3D tissue culture was developed using paired-agent molecular imaging principles. To test the methodology, the uptakes of ABY-029 (an IRDye 800CW-labeled epidermal growth factor receptor (EGFR)-targeted antibody-mimetic) and IRDye 700DX-carboxylate in 3D spheroids were measured in four different human cancer cell lines throughout staining and rinsing. A compartment model (optimized for the application) was then fit to the kinetic curves of both imaging agents to estimate binding and dissociation rate constants of the EGFR targeted ABY-029 agent. A linear correlation was observed between apparent association rate constant (k 3 ) and the receptor concentration experimentally and in simulations (r = 0.99 , p < 0.05 ). Additionally, a similar binding affinity profile compared to a gold standard method was determined by this model. This low-cost methodology to quantify imaging agent or drug binding affinity in clinically relevant 3D tumor spheroid models, can be used to guide timing of imaging in molecular guided surgery and could have implications in drug development.

Comparison of narrow band and fluorescence molecular imaging to improve intraoperative tumour margin assessment in oral cancer surgery

OBJECTIVE

New techniques have emerged to aid in preventing inadequate margins in oral squamous cell carcinoma (OSCC) surgery, but studies comparing different techniques are lacking. Here, we compared narrow band imaging (NBI) with fluorescence molecular imaging (FMI), to study which intraoperative technique best assesses the mucosal tumour margins.

MATERIALS AND METHODS

NBI was performed in vivo and borders were marked with three sutures. For FMI, patients received 75 mg of unlabelled cetuximab followed by 15 mg cetuximab-800CW intravenously-two days prior to surgery. The FMI borders were defined on the excised specimen. The NBI borders were correlated with the FMI outline and histopathology.

RESULTS

Sixteen patients were included, resulting in 31 NBI and 30 FMI measurements. The mucosal border was delineated within 1 mm of the tumour border in 4/31 (13 %) of NBI and in 16/30 (53 %) FMI cases (p = 0.0008), and within 5 mm in 23/31 (74 %) of NBI and in 29/30 (97 %) of FMI cases (p = 0.0048). The median distance between the tumour border and the imaging border was significantly greater for NBI (3.2 mm, range -6.1 to 12.8 mm) than for FMI (0.9 mm, range -3.0 to 7.4 mm; p = 0.028). Submucosal extension and previous irradiation reduced NBI accuracy.

CONCLUSION

Ex vivo FMI performed more accurately than in vivo NBI in mucosal margin assessment, mainly because NBI cannot detect submucosal extension. NBI adequately identified the mucosal margin especially in early-stage and not previously irradiated tumours, and may therefore be preferable in these tumours for practical and cost-related reasons.

Genome-Wide Association Analysis for Chronic Superficial Keratitis in the Australian Racing Greyhound

Chronic superficial keratitis (CSK) is a progressive inflammatory condition of the eye (cornea) that can cause discomfort and blindness. Differential disease risk across dog breeds strongly suggests that CSK has a genetic basis. In addition to genetic risk, the occurrence of CSK is exacerbated by exposure to ultraviolet light. Genome-wide association analysis considered 109 greyhounds, 70 with CSK and the remainder with normal phenotype at an age over four years. Three co-located variants on CFA18 near the 5' region of the Epidermal Growth Factor Receptor (EGFR) gene were associated with genome-wide significance after multiple-test correction (BICF2P579527, CFA18: 6,068,508, p_raw = 1.77 × 10^-7, p_genome = 0.017; BICF2P1310662, CFA18: 6,077,388, p_raw = 4.09 × 10^-7, p_genome = 0.040; BICF2P160719, CFA18: 6,087,347, p_raw = 4.09 × 10^-7, p_genome = 0.040) (canFam4)). Of the top 10 associated markers, eight were co-located with the significantly associated markers on CFA18. The associated haplotype on CFA18 is protective for the CSK condition. EGFR is known to play a role in corneal healing, where it initiates differentiation and proliferation of epithelial cells that in turn signal the involvement of stromal keratocytes to commence apoptosis. Further validation of the putative functional variants is required prior to their use in genetic testing for breeding programs.

Safety of osimertinib in adult patients with metastatic epidermal growth factor receptor T790M mutation-positive non-small cell lung cancer: Results from a Phase IV study in India

BACKGROUND

A Phase IV, single-arm study was conducted to assess the safety of osimertinib in Indian patients with epidermal growth factor receptor (EGFR) T790M mutation-positive stage IV non-small cell lung cancer (NSCLC).

METHODS

Enrolled patients received 80 mg osimertinib for six cycles or until disease progression or unacceptable toxicity or withdrawal. Primary safety variables included treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), and adverse events (AEs) leading to discontinuation/interruption/change (D/I/C) of drug dose, and AEs of special interest (AESIs). AEs were summarized by the percentage of patients experiencing at least one occurrence of each event.

RESULTS

Of the 60 enrolled patients (median age 58 [range: 34-81] years; 51.7% women) at eight sites, nine patients were discontinued prematurely due to disease progression (n = 7) and death (n = 2); median (range) duration of treatment was 126 (1-134) days. Median age of patients was 58 (34-81) years; 51.7% (n = 31) were women; 86.7% (n = 52) were nonsmokers; and most of them (98.3%) had adenocarcinoma. About 75% (n = 45) of patients experienced any of the TEAEs, with the most frequent being fatigue and creatine phosphokinase (CPK) increase (n = 6, 10% each). TEAEs in 11 (18.3%) patients were judged as study treatment related, with CPK increase being the most common (n = 4, 6.7%). TEAEs led to D/I/C of drug dose in eight (13.3%) patients, with one being study treatment related. Nine (15%) patients had AESIs of dyspnea (n = 6), chest pain (n = 2), and cardiorespiratory arrest (n = 1); two of them had a fatal outcome. One AESI (mild dyspnea) was considered study drug related. TEAEs of grade ≥3 were reported in seven (11.7%) patients, including dyspnea in two (3.3%), followed by diarrhea, mucosal inflammation, cardiorespiratory arrest, and others (n = 1, 1.7% each). None of the SAEs and fatal events were considered as study treatment related. Seven (11.7%) patients had abnormal electrocardiogram (ECG; not clinically significant) at the end of the study.

CONCLUSION

Our study confirms the favorable safety profile of osimertinib without any new safety concerns in Indian patients with EGFR T790M mutation-positive stage IV NSCLC.

CLINICALTRIALS.GOV IDENTIFIER

NCT03853551.

Epidermal growth factor receptor targeted fluorescence molecular imaging for postoperative lymph node assessment in patients with oral cancer

Rationale: In most oral cancer patients, surgical treatment includes resection of the primary tumor combined with the excision of lymph nodes (LN), either for staging or treatment. All LNs harvested during surgery require tissue processing and subsequent microscopic histopathological assessment to determine the nodal stage. In this study, we investigated the use of the fluorescent tracer cetuximab-800CW to discriminate between tumor-positive and tumor-negative LNs before histopathological examination. Methods: Here, we report a retrospective ad hoc analysis of a clinical trial designed for resection margin evaluation of oral squamous cell carcinoma patients (NCT02415881). Two days prior to surgery, patients were intravenously administered with 75 mg cetuximab followed by 15 mg cetuximab-800CW, an Epidermal Growth Factor Receptor (EGFR)-targeting fluorescent tracer. Fluorescence images were obtained of excised, formalin-fixed LNs and correlated with histopathological assessment. Results: Fluorescence molecular imaging of 514 LNs (61 pathologically positive nodes) can detect tumor-positive LNs ex vivo with 100% sensitivity and 86.8% specificity (AUC 0.97). In this cohort, the number of LNs that require microscopic assessment was decreased by 77.4%, without missing any metastasis. Additionally, in 7.5% of the fluorescence false-positive LNs, we identified metastases missed by standard histopathological analysis. Conclusion: Our findings suggest that EGFR-targeted fluorescence molecular imaging can aid in the detection of LN metastases in the ex vivo setting in oral cancer patients. This image-guided concept can improve the efficacy of postoperative LN examination and identify additional metastases, which safeguards appropriate postoperative therapy and may improve patient prognosis.

A novel strategy for engineering of a smart generation of immune ribonucleases against EGFR+ cells

The overexpression of epidermal growth factor receptor (EGFR) could result in the development of solid tumors of prostate, breast, gastric, colorectal, ovarian, and head and neck, leading to carcinoma. Antibody therapies are ideal methods to overcome malignant diseases. However, immunoribonucleases are a new generation of antibodies in which an RNase binds to a specific antibody and shows a stronger ability to terminate cancer cells. In this study, we engineered Rana pipiens RNase to bind to the scFv of human antiepidermal growth factor receptor antibody. The molecular dynamic simulations confirmed protein stability and the ability of scFv-ranpirnase (rantoxin) to bind to epidermal growth factor receptor protein. Then, the rantoxin construct was synthesized in a pCDNA 3.1 Neo vector. CHO-K1 cells were used as expression hosts and the construct was transfected. Cells were selected by antibiotic therapies using neomycin, 120 mg/ml, and the high-yield colony was screened by real-time polymerase chain reaction (PCR) methods. Then, the recombinant protein production was confirmed using the sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analyses. The molecular dynamic simulation (MDS) confirmed that the I467, S468, Q408, and H409 amino acids of EGFR bonded well to rantoxin. As revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analyses, the rantoxin production and PCR analysis showed that the T3 colony can produce rantoxin messenger RNA fourfold higher than the GAPDH gene. The immunotoxin function was assessed in A431 cancer cells and EGFR-negative HEK293 cells, and IC₅₀  values were estimated to be 22.4 ± 3 and >620.4 ± 5 nM, respectively. The results indicated that the immunotoxins produced in this study had the potential for use as anticancer drugs.

Relief of Neuropathic Pain Through Epidermal Growth Factor Receptor Inhibition: A Randomized Proof-of-Concept Trial

OBJECTIVE

Case reports and a case series have described relief of neuropathic pain (NP) after treatment with epidermal growth factor receptor inhibitors (EGFR-Is). These observations are supported by preclinical findings. The aim of this trial was to explore a potential clinical signal supporting the therapeutic efficacy of EGFR-Is in NP.

METHODS

In a proof-of-concept trial using a randomized, double-blind, placebo-controlled design, 14 patients with severe, chronic, therapy-resistant NP due to compressed peripheral nerves or complex regional pain syndrome were randomized to receive a single infusion of the EGFR-I cetuximab and placebo in crossover design, followed by a single open-label cetuximab infusion.

RESULTS

The mean reduction in daily average pain scores three to seven days after single-blinded cetuximab infusion was 1.73 points (90% confidence interval [CI] = 0.80 to 2.66), conferring a 1.22-point greater reduction than placebo (90% CI = -0.10 to 2.54). Exploratory analyses suggested that pain reduction might be greater in the 14 days after treatment with blinded cetuximab than after placebo. The proportion of patients who reported ≥50% reduction in average pain three to seven days after cetuximab was 36% (14% after placebo), and comparison of overall pain reduction suggests a trend in favor of cetuximab. Skin rash (grade 1-2) was the most frequent side effect (12/14, 86%).

CONCLUSIONS

This small proof-of-concept evaluation of an EGFR-I against NP did not provide statistical evidence of efficacy. However, substantial reductions in pain were reported, and confidence intervals do not rule out a clinically meaningful treatment effect. Evaluation of EGFR-I against NP therefore warrants further investigation.

P2Y2 receptors mediate nucleotide-induced EGFR phosphorylation and stimulate proliferation and tumorigenesis of head and neck squamous cell carcinoma cell lines

OBJECTIVES

To assess functional expression of the P2Y2 nucleotide receptor (P2Y2R) in head and neck squamous cell carcinoma (HNSCC) cell lines and define its role in nucleotide-induced epidermal growth factor receptor (EGFR) transactivation. The use of anti-EGFR therapeutics to treat HNSCC is hindered by intrinsic and acquired drug resistance. Defining novel pathways that modulate EGFR signaling could identify additional targets to treat HNSCC.

MATERIALS AND METHODS

In human HNSCC cell lines CAL27 and FaDu and the mouse oral cancer cell line MOC2, P2Y2R contributions to extracellular nucleotide-induced changes in intracellular free Ca2+ concentration and EGFR and extracellular signal-regulated kinase (ERK1/2) phosphorylation were determined using the ratiometric Ca2+ indicator fura-2 and immunoblot analysis, respectively. Genetic knockout of P2Y2Rs using CRISPR technology or pharmacological inhibition with P2Y2R-selective antagonist AR-C118925 defined P2Y2R contributions to in vivo tumor growth.

RESULTS

P2Y2R agonists UTP and ATP increased intracellular Ca2+ levels and ERK1/2 and EGFR phosphorylation in CAL27 and FaDu cells, responses that were inhibited by AR-C118925 or P2Y2R knockout. P2Y2R-mediated EGFR phosphorylation was also attenuated by inhibition of the adamalysin family of metalloproteases or Src family kinases. P2Y2R knockout reduced UTP-induced CAL27 cell proliferation in vitro and significantly reduced CAL27 and FaDu tumor xenograft volume in vivo. In a syngeneic mouse model of oral cancer, AR-C118925 administration reduced MOC2 tumor volume.

CONCLUSION

P2Y2Rs mediate HNSCC cell responses to extracellular nucleotides and genetic or pharmacological blockade of P2Y2R signaling attenuates tumor cell proliferation and tumorigenesis, suggesting that the P2Y2R represents a novel therapeutic target in HNSCC.

The TAGA Study: A Study of Factors Determining Aortic Diameter in Families at High Risk of Abdominal Aortic Aneurysm Reveal Two New Candidate Genes

A variety of disorders are known to be related with aortic geometry, among them abdominal aortic aneurysm (AAA). This work aims to present the main determinants of abdominal aortic diameter in a new cohort of families at high risk of AAA. The Triple-A Genomic Analysis (TAGA) study comprises 407 individuals related in 12 families. Each family was collected through a proband with AAA. We calculated heritability and genetic correlations between abdominal aortic diameter and clinical parameters. A genome-wide linkage scan was performed based on 4.6 million variants. A predictive model was calculated with conditional forest. Heritability of the abdominal aortic diameter was 34%. Old age, male sex, higher height, weight, creatinine levels in serum, and better lung capacity were the best predictors of aortic diameter. Linkage analyses suggested the implication of Epidermal Growth Factor Receptor (EGFR) and Betacellulin (BTC) genes with aortic diameter. This is the first study to evaluate genetic components of variation of the aortic diameter in a population of AAA high-risk individuals. These results reveal EGFR, a gene that had been previously implicated in AAA, as a determinant of aortic diameter variation in healthy genetically enriched individuals, and might indicate that a common genetic background could determine the diameter of the aorta and future risk of AAA.

[A Review of EGFR-TKIs Therapy of Non-small Cell Lung Cancer with Uncommon EGFR Mutations]

肺癌是目前最常见的癌症，也是导致癌症死亡的首要原因。非小细胞肺癌（non-small cell lung cancer, NSCLC）占85%以上，且高达50%的亚洲NSCLC患者携带表皮生长因子受体（epidermal growth factor receptor, EGFR）基因突变。研究证明，伴有EGFR突变的NSCLC患者接受表皮生长因子受体-酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitors, EGFR-TKIs）治疗能获得更好的生存结果。然而，因为EGFR罕见突变相对治疗效果较差，会对研究结果带来负面影响，所以大部分研究EGFR-TKIs疗效的临床试验都不包含罕见突变患者，另外EGFR罕见突变本身就少见，就导致临床试验中这部分患者数量较少。由于EGFR罕见突变样本量少且具有高度异质性，EGFR-TKIs对EGFR罕见突变患者的疗效仍然不清楚。本文就EGFR罕见突变与EGFR-TKIs的疗效关系进行综述，为携带EGFR罕见突变的NSCLC患者合理选择治疗方式提供指导和建议。

Third generation EGFR inhibitor osimertinib combined with pemetrexed or cisplatin exerts long-lasting anti-tumor effect in EGFR-mutated pre-clinical models of NSCLC

Background

The third generation Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitor (TKI) osimertinib has been initially approved for T790M positive Non-Small Cell Lung Cancer (NSCLC) and more recently for first-line treatment of EGFR-mutant T790M negative NSCLC patients. Similarly to previous generation TKIs, despite the high response rate, disease progression eventually occurs and current clinical research is focused on novel strategies to delay the emergence of osimertinib resistance. In this study we investigated the combination of osimertinib with pemetrexed or cisplatin in EGFR-mutated NSCLC cell lines and xenografts.

Methods

Tumor growth was evaluated in a PC9T790M xenograft model and tissue composition was morphometrically determined. PC9, PC9T790M and HCC827 cell lines were employed to test the efficacy of osimertinib and chemotherapy combination in vitro. Cell viability and cell death were evaluated by MTT assay and fluorescence microscopy. Protein expression and gene status were analysed by Western blotting, fluorescence in situ hybridization analysis, next-generation sequencing and digital droplet PCR.

Results

In xenograft models, osimertinib significantly inhibited tumor growth, however, as expected, in 50% of mice drug-resistance developed. A combination of osimertinib with pemetrexed or cisplatin prevented or at least delayed the onset of resistance. Interestingly, such combinations increased the fraction of fibrotic tissue and exerted a long-lasting activity after stopping therapy. In vitro studies demonstrated the stronger efficacy of the combination over the single treatments in inhibiting cell proliferation and inducing cell death in PC9T790M cells as well as in T790M negative PC9 and HCC827 cell lines, suggesting the potential role of this strategy also as first-line treatment. Finally, we demonstrated that osimertinib resistant clones, either derived from resistant tumors or generated in vitro, were less sensitive to pemetrexed prompting to use a chemotherapy regimen non-containing pemetrexed in patients after progression to osimertinib treatment.

Conclusions

Our results identify a combination between osimertinib and pemetrexed or cisplatin potentially useful in the treatment of EGFR-mutated NSCLC patients, which might delay the appearance of osimertinib resistance with long-lasting effects.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1240-x) contains supplementary material, which is available to authorized users.

Ganglioside GM1 promotes contact inhibition of growth by regulating the localization of epidermal growth factor receptor from glycosphingolipid-enriched microdomain to caveolae

Objectives

Accumulating data show that gangliosides are involved in regulation of cell proliferation. Specific changes in gangliosides expression associated with growth density of cells have been documented in several cell lines. However, the function and the potential mechanism of ganglioside GM1 in contact inhibition of growth are not clear.

Materials and Methods

EdU incorporation assay and western blot were applied to detect the contact inhibition of growth in human mammary epithelial cells. GM1 manipulation of cell proliferation and epidermal growth factor receptor (EGFR) activation was investigated by immunoprecipitation, OptiPrep density gradient centrifugation and immunofluorescence. The function of GM1 on contact inhibition of growth was further studied by using GM1 stably knockdown and overexpression cells.

Results

MCF‐10A, MCF‐7 and MDA‐MB‐231 cells showed contact inhibition of growth in high‐density condition. Exogenous addition of GM1 to high‐density cells clearly inhibited cell growth and deactivated EGFR signalling. Compared to normal‐density cells, distribution of EGFR in high‐density cells was decreased in glycosphingolipid‐enriched microdomain (GEM), but more concentrated in caveolae, and incubation with GM1 obviously promoted this translocation. Furthermore, the cell growth and EGFR activation were increased in GM1 stably knockdown cells and decreased in GM1 stably overexpression cells when cultured in high density.

Conclusions

Our results demonstrated that GM1 suppressed EGFR signalling and promoted contact inhibition of growth by changing the localization of EGFR from GEM to caveolae.

Looking for New Inhibitors for the Epidermal Growth Factor Receptor

Epidermal Growth Factor Receptor (EGFR) is still the main target of the Head and Neck Squamous Cell Cancer (HNSCC) because its overexpression has been detected in more than 90% of this type of cancer. This overexpression is usually linked with more aggressive disease, increased resistance to chemotherapy and radiotherapy, increased metastasis, inhibition of apoptosis, promotion of neoplastic angiogenesis, and, finally, poor prognosis and decreased survival. Due to this reason, the main target in the search of new drugs and inhibitors candidates is to downturn this overexpression. Quantitative Structure-Activity Relationship (QSAR) is one of the most widely used approaches while looking for new and more active inhibitors drugs. In this contest, a lot of authors used this technique, combined with others, to find new drugs or enhance the activity of well-known inhibitors. In this paper, on one hand, we will review the most important QSAR approaches developed in the last fifteen years, spacing from classical 1D approaches until more sophisticated 3D; the first paper is dated 2003 while the last one is from 2017. On the other hand, we will present a completely new QSAR approach aimed at the prediction of new EGFR inhibitors drugs. The model presented here has been developed over a dataset consisting of more than 1000 compounds using various molecular descriptors calculated with the DRAGON 7.0© software.

Mitochondrial DNA copy number instability in ERBB2-amplified breast cancer tumors

Increase in the copy number of ERBB2, a Tyrosine Kinase Receptor (TKR) leads to the overexpression of oncogene product and consequently uncontrolled cell proliferation which has been reported in different aggressive cancers with mitochondrial malfunctions. Although, amplification of ERBB2 has been reported in different studies; however, the association between changes in mitochondrial DNA content and the ERBB2 gene copy number is poorly understood. The relative mitochondrial DNA content of breast cancer tumor tissues of 70 patients who were referred to Imam Khomeini Hospital Complex was determined using quantitative Real-time PCR. Multiplex ligation-dependent probe amplification (MLPA) was conducted to evaluate the ERBB2 gene copy number variation and finally, two-sample Wilcoxon rank-sum (Mann-Whitney) test was used to investigate the possible association between mitochondrial DNA (mtDNA) content and the ERBB2 gene amplification. Seventeen out of 70 breast cancer tumor tissues were found with ERBB2 gene amplification. Comparison of the mitochondrial DNA content of the aforementioned samples with the rest of the cases showed a significant decrease in the mitochondrial DNA content of the ERBB2-amplified samples (P=0.01). Our data provided evidence that ERBB2 have the potential to have a regulatory role over mitochondrial activity by controlling the mtDNA content.

Overall Survival Analysis and Characterization of an EGFR Mutated Non-Small Cell Lung Cancer (NSCLC) Population

BACKGROUND

Patients with activating somatic mutations in the Epidermal Growth Factor Receptor (EGFR) have better clinical outcomes when treated with Tyrosine Kinase Inhibitors (TKI) over chemotherapy. However, the impact of the use of TKIs on overall survival outside clinical trials is not well established.

OBJECTIVE

To characterize and analyze the overall survival of a Caucasian population with NSCLC and EGFR mutations.

METHODS

A retrospective cohort analysis of patients with NSCLC screened for EGFR mutations (exons 18-21) between October 2009 and July 2013 was conducted. Clinical and pathological characteristics, mutational EGFR status, treatment and overall survival were evaluated.

RESULTS

From the 285 patients which performed screening for EGFR mutations, 54 (18.9%) had mutations, 25 (46.3%) of which in exon 19 and 20 of which (37.0%) in exon 21. The occurrence of mutations was associated with female sex and non-smoking habits (both, P<.001). The median survival of the global population was 12.0 months, with a better overall survival in mutated than non-mutated patients (20.0 vs 11.0 months, respectively; P=.007).

CONCLUSION

These data contribute for a better knowledge of our lung cancer population concerning the mutational status and clinical outcomes, confirming a better overall survival for the patients with EGFR TKI sensible mutations.

Trends and Outcomes of Non-Small-Cell Lung Cancer in Omani Patients: Experience at a university hospital

OBJECTIVES

The incidence of lung cancer in Oman has shown a gradual but definitive increase since 2002. This study aimed to evaluate the demographic and epidemiological characteristics and survival outcomes of patients with non-small-cell lung cancer (NSCLC) at a university hospital in Oman.

METHODS

This study was conducted from January to June 2016. A retrospective analysis was performed of consecutive patients diagnosed with NSCLC presenting to the Sultan Qaboos University Hospital (SQUH) in Muscat, Oman, between March 2000 and December 2015. Clinical features at presentation and prognostic and predictive markers were reviewed. Kaplan-Meir estimates were used to determine relapse-free survival, progression-free survival (PFS) and overall survival (OS).

RESULTS

A total of 104 patients presented to SQUH during the study period. The median age at diagnosis was 64 years. Overall, 62 patients (59.6%) had adenocarcinomas. Only 12 patients (11.5%) presented in the early stages (I or II) of the disease and the majority of patients had an Eastern Cooperative Oncology Group performance status of 1 (27.9%) or 2 (26.0%). The prevalence of epidermal growth factor receptor mutations was 27.9%. The median PFS for patients with advanced disease (stages III or IV) was five months and the median OS for all patients was seven months. After five years, 50.0%, 60.0%, 10.0% and 8.0% of patients with disease stages I, II, III and IV, respectively, were alive.

CONCLUSION

Patients with NSCLC in Oman were found to present at an advanced stage. However, patient outcomes were similar to those reported in the USA.

Patient Experience of Symptoms and Side Effects when Treated with Osimertinib for Advanced Non-Small-Cell Lung Cancer: A Qualitative Interview Substudy

INTRODUCTION

Capturing the patient experience during treatment is important to both regulatory authorities and to patients starting treatment. We identified the symptoms and side effects experienced by patients with advanced non-small-cell lung cancer during osimertinib treatment, to understand treatment expectations, satisfaction, and the level of difficulty coping with the side effects experienced during treatment.

METHODS

Qualitative interviews (approximately 4-6 weeks after treatment initiation and again after approximately 4 months of treatment) were conducted during the phase I/II AURA clinical trial of osimertinib, a tyrosine kinase inhibitor of epidermal growth factor receptor-sensitizing and T790M resistance mutations.

RESULTS

During the first interview (23 patients), the most commonly reported symptoms/side effects were coughing, itching, tiredness (each reported by 56.5% of patients), and rash (43.5%). During the second interview (21 patients), compared with the first interview, shortness of breath and diarrhea were reported by more patients (57.1 and 38.1%, respectively; both increased from 34.8%); tiredness remained predominant (42.9%); and itching (38.1%), coughing (38.1%), and rash (14.3%) were reported by fewer patients. At both interviews, the most frequently reported symptoms/side effects were also those most often rated by patients for bothersomeness and severity, and generally received mean scores in the low-to-moderate range. However, several rarely expressed symptoms/side effects (e.g., abdominal pain, frequent day time urination) received high bothersomeness ratings. At the second interview, patients were highly satisfied with osimertinib and had a low level of difficulty in coping with side effects during treatment.

CONCLUSIONS

These data enhance our understanding of patients' experiences of symptoms/side effects, which could increase the accuracy of the osimertinib benefit-risk assessment, guide management of adverse events, and improve the information given to patients receiving the drug.

EGFR-mediated apoptosis via STAT3

The Epidermal Growth Factor Receptor (EGFR) is a cell surface receptor with primary implications in cell growth in both normal and malignant tissue. Paradoxically, cell lines that hyperexpress the EGFR have been documented to undergo receptor-mediated apoptosis. The underlying mechanism by which EGF-induced apoptosis occurs however remains inexplicit. In an attempt to identify this mechanism, we assessed downstream effectors of EGFR in MDA-MB-468 cells during conditions of EGF-induced apoptosis. The effector assessment revealed STAT3 as a potential mediator of EGF-induced apoptosis. Alternative strategies for activating STAT3, independent of EGFR stimulation, resulted in the induction of the apoptotic pathways. A reduction in STAT3 expression via RNAi resulted in a significant attenuation of EGF-induced PARP cleavage. Our findings support STAT3 as a positive mediator of EGF-induced apoptosis in MDA-MB-468 cells.

Radiotherapy plus EGFR inhibitors: synergistic modalities

Locally advanced (stage III or IV) squamous cell carcinoma of the head and neck (SCCHN) often requires multimodal treatment, consisting of a combination of surgery, radiation, and/or systemic therapy, namely chemotherapy or targeted agents. The expression of the epidermal growth factor receptor (EGFR) has been detected in more than 90% of all cases of SCCHN and has been correlated with decreased survival rates, resistance to radiotherapy, loco-regional treatment failure, and increased rates of distant metastases. This paper discusses several strategies aimed at targeting EGFR in combination with radiation. Until now, cetuximab, an anti-EGFR monoclonal antibody, is the only targeted agent that has been shown to improve overall survival in combination with radiation therapy. However, considering that there are multiple mechanisms of primary and acquired resistance to EGFR inhibitors, we focused on dissecting molecular pathways of EGFR inhibition to find alternative or complementary strategies for increasing tumour responsiveness. We suggest that the combination of treatments targeting the EGFR pathway and drugs aimed at increasing immune responses represent a promising approach that deserves to be further explored.

Targeted Lung Cancer Treatments and Eye Metastasis

Lung cancer remains the leading cause of death due to cancer. We do not have effective tools for the early detection of lung cancer, so patients are usually diagnosed at an advanced stage. However, novel therapies based on molecular pathways (such as those involving the epidermal growth factor receptor, anaplastic lymphoma kinase, serine/threonine-protein kinase B-Raf, proto-oncogene tyrosine-protein kinase ROS, c-Met proto-oncogene protein, and RET proto-oncogene protein) are now commonly used in the treatment of lung cancer. In particular, these therapies are considered as first-line treatments for non-small-cell lung cancer. This manuscript outlines previous research on these targeted treatments, focusing on whether they are effective against eye metastasis.

Association Study of Polymorphisms of Epidermal Growth Factor and Epidermal Growth Factor Receptor With Benign Prostatic Hyperplasia in a Korean Population

Purpose

Recent studies have suggested that specific single-nucleotide polymorphisms (SNPs) contribute to the clinical features of benign prostatic hyperplasia (BPH). In this study, we investigated the relationships of genetic polymorphisms of the epidermal growth factor (EGF) gene and the epidermal growth factor receptor (EGFR) gene with BPH.

Methods

A total of 218 patients with BPH were enrolled in this study. We evaluated the relationship between eight SNPs in the EGF and EGFR genes and prostate volume, prostate-specific antigen (PSA), and International Prostate Symptom Score of BPH patients. Each SNP was genotyped by direct sequencing. Statistical analysis applying codominant, dominant, recessive, and log-additive models was performed via logistic regression.

Results

The rs11568943 and rs11569017 SNPs in the EGF gene showed significant associations with prostate volume (rs11568943: P=0.038 in the log-additive model, P=0.024 in the allele distribution; rs11569017, P=0.031 in the dominant model, P=0.028 in the log-additive model, P=0.020 in the allele distribution). Additionally, the rs3756261, rs11568943, and rs11569017 SNPs of the EGF gene and the rs2293347 SNP of the EGFR gene were associated with PSA levels (P<0.05 in each model, respectively).

Conclusions

These results suggest that the EGF gene may affect prostate volume. In addition, the EGF and EGFR genes may be associated with PSA levels in patients with BPH.

Molecular Docking Optimization in the Context of Multi-Drug Resistant and Sensitive EGFR Mutants

The human Epidermal Growth Factor (EGFR) plays an important role in signaling pathways, such as cell proliferation and migration. Mutations like G719S, L858R, T790M, G719S/T790M or T790M/L858R can alter its conformation, and, therefore, drug responses from lung cancer patients. In this context, candidate drugs are being tested and in silico studies are necessary to know how these mutations affect the ligand binding site. This problem can be tackled by using a multi-objective approach applied to the molecular docking problem. According to the literature, few studies are related to the application of multi-objective approaches by minimizing two or more objectives in drug discovery. In this study, we have used four algorithms (NSGA-II, GDE3, SMPSO and MOEA/D) to minimize two objectives: the ligand-receptor intermolecular energy and the RMSD score. We have prepared a set of instances that includes the wild-type EGFR kinase domain and the same receptor with somatic mutations, and then we assessed the performance of the algorithms by applying a quality indicator to evaluate the convergence and diversity of the reference fronts. The MOEA/D algorithm yields the best solutions to these docking problems. The obtained solutions were analyzed, showing promising results to predict candidate EGFR inhibitors by using this multi-objective approach.

Excessive Reversal of Epidermal Growth Factor Receptor and Ephrin Signaling Following Tracheal Occlusion in Rabbit Model of Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) causes severe pulmonary hypoplasia from herniation of abdominal contents into the thorax. Tracheal occlusion (TO) for human CDH improves survival, but morbidity and mortality remain high, and we do not fully understand the cellular pathways and processes most severely impacted by CDH and TO. We created a left diaphragmatic hernia (DH) in rabbit fetuses with subsequent TO and collected left lung sections for NextGen mRNA sequencing. DH, TO, and DHTO fetuses had comparable body and organ growth to control except for lower lung weights in DH (p<0.05). Of 13,687 expressed genes, DHTO had 687 differentially expressed genes compared to DH, but no other group-group comparison had more than 10. Considering genes in combination, many of the genes reduced in DH were more highly expressed in DHTO than in control. Benchmarking fetal rabbit lung gene expression to published lung development data, both DH and DHTO lungs were more highly correlated with the gene expression of immature lung. DNA synthesis was upregulated in DHTO compared to DH and ribosome and protein synthesis pathways were downregulated. DH reduced total and epithelial cell proliferation by half and two-thirds respectively, and DHTO increased proliferation by 2.5 and 3.4-fold respectively. Signaling pathways downregulated by DH and upregulated in DHTO were epidermal growth factor receptor signaling, ephrin signaling, and cell migration; however, levels of ephrin and EGFR signaling in DHTO exceeded that of control. Identification and inhibition of the ligands responsible for this dysregulated signaling could improve lung development in CDH.

Protein Kinase G facilitates EGFR-mediated cell death in MDA-MB-468 cells

The Epidermal Growth Factor Receptor (EGFR) is a transmembrane receptor tyrosine kinase with critical implications in cell proliferation, migration, wound healing and the regulation of apoptosis. However, the EGFR has been shown to be hyper-expressed in a number of human malignancies. The MDA-MB-468 metastatic breast cell line is one example of this. This particular cell line hyper-expresses the EGFR and undergoes EGFR-mediated apoptosis in response to EGF ligand. The goal of this study was to identify the kinases that could be potential intermediates for the EGFR-mediated induction of apoptosis intracellularly. After identifying Cyclic GMP-dependent Protein Kinase G (PKG) as a plausible intermediate, we wanted to determine the temporal relationship of these two proteins in the induction of apoptosis. We observed a dose-dependent decrease in MDA-MB-468 cell viability, which was co-incident with increased PKG activity as measured by VASPSer239 phosphorylation. In addition, we observed a dose dependent decrease in cell viability, as well as an increase in apoptosis, in response to two different PKG agonists, 8-Bromo-cGMP and 8-pCPT-cGMP. MDA-MB-468 cells with reduced PKG activity had attenuated EGFR-mediated apoptosis. These findings indicate that PKG does not induce cell death via transphosphorylation of the EGFR. Instead, PKG activity occurs following EGFR activation. Together, these data indicate PKG as an intermediary in EGFR-mediated cell death, likely via apoptotic pathway.

Myths in the Diagnosis and Management of Orbital Tumors

Orbital tumors constitute a group of diverse lesions with a low incidence in the population. Tumors affecting the eye and ocular adnexa may also secondarily invade the orbit. Lack of accumulation of a sufficient number of cases with a specific diagnosis at various orbital centers, the paucity of prospective randomized studies, animal model studies, tissue bank, and genetic studies led to the development of various myths regarding the diagnosis and treatment of orbital lesions in the past. These myths continue to influence the diagnosis and treatment of orbital lesions by orbital specialists. This manuscript discusses some of the more common myths through case summaries and a review of the literature. Detailed genotypic analysis and genetic classification will provide further insight into the pathogenesis of many orbital diseases in the future. This will enable targeted treatments even for diseases with the same histopathologic diagnosis. Phenotypic variability within the same disease will be addressed using targeted treatments.

Association of EGF Receptor and NLRs signaling with Cardiac Inflammation and Fibrosis in Mice Exposed to Fine Particulate Matter

ЄAmbient fine particulate matter (PM2.5 ) could induce cardiovascular diseases (CVD), but the mechanism remains unknown. To investigate the roles of epidermal growth factor receptor (EGFR) and NOD-like receptors (NLRs) in PM2.5 -induced cardiac injury, we set up a BALB/c mice model of PM2.5 -induced cardiac inflammation and fibrosis with intratracheal instillation of PM2.5 suspension (4.0 mg/kg b.w.) for 5 consecutive days (once per day). After exposure, we found that mRNA levels of CXCL1, interleukin (IL)-6, and IL-18 were elevated, but interestingly, mRNA level of NLRP12 was significant decreased in heart tissue from PM2.5 -induced mice compared with those of saline-treated mice using real-time PCR. Protein levels of phospho-EGFR (Tyr1068), phospho-Akt (Thr308), NLRP3, NF-κB-p52/p100, and NF-κB-p65 in heart tissue of PM2.5 -exposed mice were all significantly increased using immunohistochemistry or Western blotting. Therefore, PM2.5 exposure could induce cardiac inflammatory injury in mice, which may be involved with EGFR/Akt signaling, NLRP3, and NLRP12.

Evaluating the Prevalence of the Epidermal Growth Factor Receptor in Transitional Cell Carcinoma of Bladder and its Relationship With Other Prognostic Factors

Background:

The most common malignancy in the urinary system has been bladder cancer and the most predominant histologic subtype has been transitional cell carcinoma (TCC). There were many molecular risk factors, related with poor prognosis. One of these factors was expression of epidermal growth factor receptor (EGFR).

Objectives:

The aim of this study was to evaluate the prevalence of the epidermal growth factor receptor in transitional cell carcinoma of bladder and its relationship with other prognostic factors.

Patients and Methods:

This analytic descriptive study has performed with 61 patients with TCC of bladder after radical cystectomy whom have been hospitalized in Labbafinejad hospital in Tehran, Iran between 2007 and 2010. We have used Chi-square and t-test to analyze our data samples.

Results:

Records of 61 patients have studied. Fifty three of the total samples were positive for EGFR expression (86.9%). Fifty samples of these fifty-three belonged to men and three others were women’s samples (P = 0.46). Among the group with EGFR expression the results were as follows: 25 patients (47.2%) were 60 years old or less and 28 patients (52.8%) were older than 60 (P = 0.023), 16 patients (30.2%) had invasion to lamina properia, and the rest of them had invasion to deeper layers (P = 0.56). For most patients we could not determine the invasion of tumoral cells into the lymph nodes (Nx) (P = 0.067). Thirty four patients (64.2%) had not lymphovascular invasion (P = 0.44) and in forty three of patients (81.1%), perineural invasion have not seen (P = 0.23). Finally, 36 patients (67.9%) were grade 3 (P = 0.27).

Conclusions:

In this study we have concluded that most patients had EGFR positive expression. Also, except for the age, there was not any significant relation between expression of EGFR and the other prognostic factors such as, gender, invasion of the tumor into the layers, involving the lymph nodes, lymphovascular or perineural invasion, and grading.

Signaling mechanisms of resistance to EGFR- and Anti-Angiogenic Inhibitors cancer

Colorectal cancer is among four most common malignancies and the second leading cause of cancer death in the western world. Epidermal Growth Factor Receptor (EGFR) and Vascular Endothelial Growth Factor (VEGF) are often overexpressed in colorectal cancer and are associated with inferior outcomes. More recently, further improvements in survival have occurred due to the use of novel targeted therapies such EGFR Tyrosine Kinase Inibitors (EGFR-TKIs), EGFR monoclonal antibodies (EGFR-mAb), and VEGF antibodies. Despite the initial clinical efficacy of these inhibitors in such cancer, resistance invariably develops, typically within 1 to 2 years. Over the past several years, multiple molecular mechanisms of resistance have been identified, and some common themes have emerged. One is the development of resistance mutations in the drug target and another it is activation of alternative signaling of key downstream pathways despite sustained inhibition of the original drug target. In this mini-review, we summarize the concepts underlying EGFR- and VEGF-mediated resistance, the specific examples known to date, and the challenges of applying this knowledge to develop improved therapeutic strategies to prevent or overcome resistance.

Determining the geometry of oligomers of the human epidermal growth factor family on cells with 7 nm resolution

Dimerisation, oligomerisation, and clustering of receptor molecules are important for control of the signalling process. There has been a lack of suitable methods for the study and quantification of these processes in cells. Here we describe a protocol for a method that we have named "fluorophore localisation imaging with photobleaching" (FLImP), which uses single molecule localisation and single-step photobleaching to determine the separation of two fluorophores with a resolution of 7 nm or better. We describe the procedures required for the collection of FLImP data, and point out some of the pitfalls that must be avoided for the collection of high resolution data. We also present recent data obtained using FLImP, showing that the intracellular domain of the Epidermal Growth Factor Receptor is not required in the basal state for the receptor to form ordered inactive oligomers in the plasma membrane.

RAB7 and TSG101 are required for the constitutive recycling of unliganded EGFRs via distinct mechanisms

Both constitutive and ligand-mediated membrane trafficking regulate Epidermal Growth Factor Receptor (EGFR) signaling. The constitutive endocytosis and recycling of the unliganded EGFR is a critical determinant of cell surface EGFR expression and the cell's sensitivity to ligands. We report that two proteins with established roles in trafficking the EGF:EGFR complex to the lysosome also regulate the recycling of the unliganded EGFR. Knock down of either Tumor suppressor gene 101 (TSG101) or RAB7 causes the endosomal accumulation of the inactive, unliganded receptor in morphologically and biochemically distinct organelles. Knock down of TSG101 causes the EGFR to accumulate in low density endosomes whereas RAB7 knock down results in EGFR accumulation in high density endosomes. Knock down of either protein caused the receptor to co-localize primarily with LAMP-1, but not EEA1. These two proteins regulate EGFR slow, perinuclear recycling, via distinct mechanism and are new molecular targets that regulate cell surface EGFR expression.

Qualitative changes in the proteome of extracellular vesicles accompanying cancer cell transition to mesenchymal state

Transitions of the cancer cell phenotype between epithelial and mesenchymal states (EMT) are likely to alter the patterns of intercellular communication. In this regard we have previously documented that EMT-like changes trigger quantitative rearrangements in exosomal vesicle emission in A431 cancer cells driven by oncogenic epidermal growth factor receptor (EGFR). Here we report that extracellular vesicles (EVs) produced by these cancer cells in their epithelial and mesenchymal states exhibit profound qualitative differences in their proteome. Thus, induction of the EMT-like state through blockade of E-cadherin and EGFR stimulation provoked a mesenchymal shift in cellular morphology and enrichment in the CD44-high/CD24-low immunophenotype, often linked to cellular stemness. This change also resulted in reprogramming of the EV-related proteome (distinct from that of corresponding cells), which contained 30 unique protein signals, and revealed enrichment in pathways related to cellular growth, cell-to-cell signaling, and cell movement. Some of the most prominent EV-related proteins were validated, including integrin α2 and tetraspanin CD9. We propose that changes in cellular differentiation status translate into unique qualitative rearrangements in the cargo of EVs, a process that may have implications for intercellular communication and could serve as source of new biomarkers to detect EMT-like processes in cancer.

NOX4 mediates cytoprotective autophagy induced by the EGFR inhibitor erlotinib in head and neck cancer cells

Most head and neck squamous cell carcinomas (HNSCCs) overexpress epidermal growth factor receptor (EGFR) and EGFR inhibitors are routinely used in the treatment of HNSCC. However, many HNSCC tumors do not respond or become refractory to EGFR inhibitors. Autophagy, which is a stress-induced cellular self-degradation process, has been reported to reduce the efficacy of chemotherapy in various disease models. The purpose of this study is to determine if the efficacy of the EGFR inhibitor erlotinib is reduced by activation of autophagy via NOX4-mediated oxidative stress in HNSCC cells. Erlotinib induced the expression of the autophagy marker LC3B-II and autophagosome formation in FaDu and Cal-27 cells. Inhibition of autophagy by chloroquine and knockdown of autophagy pathway genes Beclin-1 and Atg5 sensitized both cell lines to erlotinib-induced cytotoxicity, suggesting that autophagy may serve as a protective mechanism. Treatment with catalase (CAT) and diphenylene iodonium (DPI) in the presence of erlotinib suppressed the increase in LC3B-II expression in FaDu and Cal-27 cells. Erlotinib increased NOX4 mRNA and protein expression by increasing its promoter activity and mRNA stability in FaDu cells. Knockdown of NOX4 using adenoviral siNOX4 partially suppressed erlotinib-induced LC3B-II expression, while overexpression of NOX4 increased expression of LC3B-II. These studies suggest that erlotinib may activate autophagy in HNSCC cells as a pro-survival mechanism, and NOX4 may play a role in mediating this effect.

Oxidative stress induced by P2X7 receptor stimulation in murine macrophages is mediated by c-Src/Pyk2 and ERK1/2

BACKGROUND

Activation of ATP-gated P2X7 receptors (P2X7R) in macrophages leads to production of reactive oxygen species (ROS) by a mechanism that is partially characterized. Here we used J774 cells to identify the signaling cascade that couples ROS production to receptor stimulation.

METHODS

J774 cells and mP2X7-transfected HEK293 cells were stimulated with Bz-ATP in the presence and absence of extracellular calcium. Protein inhibitors were used to evaluate the physiological role of various kinases in ROS production. In addition, phospho-antibodies against ERK1/2 and Pyk2 were used to determine activation of these two kinases.

RESULTS

ROS generation in either J774 or HEK293 cells (expressing P2X7, NOX2, Rac1, p47phox and p67phox) was strictly dependent on calcium entry via P2X7R. Stimulation of P2X7R activated Pyk2 but not calmodulin. Inhibitors of MEK1/2 and c-Src abolished ERK1/2 activation and ROS production but inhibitors of PI3K and p38 MAPK had no effect on ROS generation. PKC inhibitors abolished ERK1/2 activation but barely reduced the amount of ROS produced by Bz-ATP. In agreement, the amount of ROS produced by PMA was about half of that produced by Bz-ATP.

CONCLUSIONS

Purinergic stimulation resulted in calcium entry via P2X7R and subsequent activation of the PKC/c-Src/Pyk2/ERK1/2 pathway to produce ROS. This signaling mechanism did not require PI3K, p38 MAPK or calmodulin.

GENERAL SIGNIFICANCE

ROS is generated in order to kill invading pathogens, thus elucidating the mechanism of ROS production in macrophages and other immune cells allow us to understand how our body copes with microbial infections.

VEGF as a predictor for response to definitive chemoradiotherapy and COX-2 as a prognosticator for survival in esophageal squamous cell carcinoma

We investigated the patterns of pretreatment expression of the epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) by immunohistochemical staining and determined their correlation with treatment response and survival in 44 patients with esophageal squamous cell carcinoma (ESCC) treated with definitive concurrent chemoradiotherapy (CCRT). The definitive CCRT consisted of a median dose of 54 Gy (range: 40.0-68.4 Gy) and two cycles of concurrent administration of mostly 5-fluorouracil + cisplatinum. High expression of EGFR, VEGF, and COX-2 was found in 79.5%, 31.8%, and 38.6%, respectively. The Cox regression analysis for overall survival (OS) showed that both the treatment response and COX-2 expression were significant. The 3-yr OS rates of patients that achieved a complete response and those that did not were 46.7% and 5.3%, respectively (P = 0.006). The logistic regression analysis for treatment response with various parameters showed that only a high expression of VEGF was significantly associated with a complete response. Unlike other well-known studies, higher expression of VEGF was significantly correlated with a complete response to CCRT in this study. However, higher expression of COX-2 was significantly associated with shorter survival. These results suggest that VEGF might be a predictive factor for treatment response and COX-2 a prognostic factor for OS in patients with ESCC after definitive CCRT.