EGFR family: structure physiology signalling and therapeutic targets

Long road towards effective HER3 targeting in breast cancer

Breast cancer is a heterogeneous disease, encompassing multiple different subtypes. Thanks to the increasing knowledge of the diverse biological features of each subtype, most patients receive personalized treatment based on known biomarkers. However, the role of some biomarkers in breast cancer evolution is still unknown, and their potential use as a therapeutic target is still underexplored. HER3 is a member of the human epidermal growth factors receptor family, overexpressed in 50%-70% of breast cancers. HER3 plays a key role in cancer progression, metastasis development, and drug resistance across all the breast cancer subtypes. Owing to its critical role in cancer progression, many HER3-targeting therapies have been developed over the past decade with conflicting findings. Next-generation antibody-drug conjugates have recently shown promising results in solid tumors expressing HER3, including breast cancer. In this review, we discuss the HER3 role in the pathogenesis of breast cancer and its relevance across all subtypes. We also explore the new anti-HER3 treatment strategies, calling into question the significance of HER3 detection as crucial information in breast cancer treatment.

HUNK as a key regulator of tumor-associated macrophages in triple negative breast cancer

Triple-negative breast cancer (TNBC) lacks the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). TNBC tumors are not sensitive to endocrine therapy, and standardized TNBC treatment regimens are lacking. TNBC is a more immunogenic subtype of breast cancer, making it more responsive to immunotherapy intervention. Tumor-associated macrophages (TAMs) constitute one of the most abundant immune cell populations in TNBC tumors and contribute to cancer metastasis. This study examines the role of the protein kinase HUNK in tumor immunity. Gene expression analysis using NanoString's nCounter PanCancer Immune Profiling panel identified that targeting HUNK is associated with changes in the IL-4/IL-4 R cytokine signaling pathway. Experimental analysis shows that HUNK kinase activity regulates IL-4 production in mammary tumor cells, and this regulation is dependent on STAT3. In addition, HUNK-dependent regulation of IL-4 secreted from tumor cells induces polarization of macrophages into an M2-like phenotype associated with TAMs. In return, IL-4 induces cancer metastasis and macrophages to produce epidermal growth factor. These findings delineate a paracrine signaling exchange between tumor cells and TAMs regulated by HUNK and dependent on IL-4/IL-4 R. This highlights the potential of HUNK as a target for reducing TNBC metastasis through modulation of the TAM population.

HER2 puzzle pieces: Non-Coding RNAs as keys to mechanisms, chemoresistance, and clinical outcomes in Ovarian cancer

Ovarian cancer (OC) presents significant challenges, characterized by limited treatment options and therapy resistance often attributed to dysregulation of the HER2 signaling pathway. Non-coding RNAs (ncRNAs) have emerged as key players in regulating gene expression in OC. This comprehensive review underscores the pivotal role of ncRNAs in modulating HER2 signaling, with a specific focus on their mechanisms, impact on chemoresistance, and prognostic/diagnostic implications. MicroRNAs, long non-coding RNAs, and circular RNAs have been identified as essential regulators in the modulation of the HER2 pathway. By directly targeting key components of the HER2 axis, these ncRNAs influence its activation and downstream signaling cascades. Dysregulated ncRNAs have been closely associated with chemoresistance, leading to treatment failures and disease progression in OC. Furthermore, distinct expression profiles of ncRNAs hold promise as reliable prognostic and diagnostic markers, facilitating personalized treatment strategies and enhancing disease outcome assessments. A comprehensive understanding of how ncRNAs intricately modulate HER2 signaling is imperative for the development of targeted therapies and the improvement of patient outcomes. The integration of ncRNA profiles into clinical practice has the potential to enhance prognostic and diagnostic accuracy in the management of ovarian cancer. Further research efforts are essential to validate the clinical utility of ncRNAs and elucidate their precise roles in the regulation of HER2 signaling. In conclusion, ncRNAs play a crucial role in governing HER2 signaling in ovarian cancer, impacting chemoresistance and providing valuable prognostic and diagnostic insights. The exploration of ncRNA-mediated HER2 modulation offers promising avenues for the development of personalized treatment approaches, ultimately advancing patient care and outcomes in OC.

Exploring ncRNA-mediated regulation of EGFR signalling in glioblastoma: From mechanisms to therapeutics

Glioblastoma (GBM) is the most prevalent and deadly primary brain tumor type, with a discouragingly low survival rate and few effective treatments. An important function of the EGFR signalling pathway in the development of GBM is to affect tumor proliferation, persistence, and treatment resistance. Advances in molecular biology in the last several years have shown how important ncRNAs are for controlling a wide range of biological activities, including cancer progression and development. NcRNAs have become important post-transcriptional regulators of gene expression, and they may affect the EGFR pathway by either directly targeting EGFR or by modifying important transcription factors and downstream signalling molecules. The EGFR pathway is aberrantly activated in response to the dysregulation of certain ncRNAs, which has been linked to GBM carcinogenesis, treatment resistance, and unfavourable patient outcomes. We review the literature on miRNAs, circRNAs and lncRNAs that are implicated in the regulation of EGFR signalling in GBM, discussing their mechanisms of action, interactions with the signalling pathway, and implications for GBM therapy. Furthermore, we explore the potential of ncRNA-based strategies to overcome resistance to EGFR-targeted therapies, including the use of ncRNA mimics or inhibitors to modulate the activity of key regulators within the pathway.

Marine-derived EGFR inhibitors: novel compounds targeting breast cancer growth and drug resistance

Breast cancer (BC) continues to be a major health challenge globally, ranking as the fifth leading cause of cancer mortality among women, despite advancements in cancer detection and treatment. In this study, we identified four novel compounds from marine organisms that effectively target and inhibit the Epidermal Growth Factor Receptor (EGFR), crucial for BC cell growth and proliferation. These compounds not only induced early apoptosis through Caspase-3 activation but also showed significant inhibitory effects on EGFR mutations associated with drug resistance (T790M, L858R, and L858R/T790M), demonstrating high EGFR kinase selectivity. Cell Thermal Shift Assay (CETSA) experiments indicated that Tandyukisin stabilizes EGFR in a concentration-dependent manner. Furthermore, binding competition assays using surface plasmon resonance technology revealed that Tandyukisin and Trichoharzin bound to distinct sites on EGFR and that their combined use enhanced apoptosis in BC cells. This discovery may pave the way for developing new marine-derived EGFR inhibitors, offering a promising avenue for innovative cancer treatment strategies and addressing EGFR-mediated drug resistance.

DB-1310, an ADC comprised of a novel anti-HER3 antibody conjugated to a DNA topoisomerase I inhibitor, is highly effective for the treatment of HER3-positive solid tumors

BACKGROUND

HER3 (ErbB3), a member of the human epidermal growth factor receptor family, is frequently overexpressed in various cancers. Multiple HER3-targeting antibodies and antibody-drug conjugates (ADCs) were developed for the solid tumor treatment, however none of HER3-targeting agent has been approved for tumor therapy yet. We developed DB-1310, a HER3 ADC composed of a novel humanized anti-HER3 monoclonal antibody covalently linked to a proprietary DNA topoisomerase I inhibitor payload (P1021), and evaluate the efficacy and safety of DB-1310 in preclinical models.

METHODS

The binding of DB-1310 to Her3 and other HER families were measured by ELISA and SPR. The competition of binding epitope for DB-1310 and patritumab was tested by FACS. The sensitivity of breast, lung, prostate and colon cancer cell lines to DB-1310 was evaluated by in vitro cell killing assay. In vivo growth inhibition study evaluated the sensitivity of DB-1310 to Her3 + breast, lung, colon and prostate cancer xenograft models. The safety profile was also measured in cynomolgus monkey.

RESULTS

DB-1310 binds HER3 via a novel epitope with high affinity and internalization capacity. In vitro, DB-1310 exhibited cytotoxicity in numerous HER3 + breast, lung, prostate and colon cancer cell lines. In vivo studies in HER3 + HCC1569 breast cancer, NCI-H441 lung cancer and Colo205 colon cancer xenograft models showed DB-1310 to have dose-dependent tumoricidal activity. Tumor suppression was also observed in HER3 + non-small cell lung cancer (NSCLC) and prostate cancer patient-derived xenograft (PDX) models. Moreover, DB-1310 showed stronger tumor growth-inhibitory activity than patritumab deruxtecan (HER3-DXd), which is another HER3 ADC in clinical development at the same dose. The tumor-suppressive activity of DB-1310 synergized with that of EGFR tyrosine kinase inhibitor, osimertinib, and exerted efficacy also in osimertinib-resistant PDX model. The preclinical assessment of safety in cynomolgus monkeys further revealed DB-1310 to have a good safety profile with a highest non severely toxic dose (HNSTD) of 45 mg/kg.

CONCLUSIONS

These finding demonstrated that DB-1310 exerted potent antitumor activities against HER3 + tumors in in vitro and in vivo models, and showed acceptable safety profiles in nonclinical species. Therefore, DB-1310 may be effective for the clinical treatment of HER3 + solid tumors.

Identification and characterization of novel ERBB4 variant associated with sporadic amyotrophic lateral sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS) is the most common type of motor neuron disease characterized by progressive motor neuron degeneration in brain and spinal cord. Most cases are sporadic in ALS and 5-10% of cases are familiar. >50 genes are known to be associated with ALS and one of them is ERBB4. In this paper, we report the case of a 53-year-old ALS patient with progressive muscle weakness and fasciculation, but he had no cognitive decline. We performed the next generation sequencing (NGS) and in silico analysis, it predicted a highly pathogenic variant, c.2116 A > G, p.Asn706Asp (N706D) in the ERBB4 gene. The amino acid residue is highly conserved among species. ERBB4 is a member of the ERBB family of receptor tyrosine kinases. ERBB4 has multiple tyrosine phosphorylation sites, including an autophosphorylation site at tyrosine 1284 residue. Autophosphorylation of ERBB4 promotes biological activity and it associated with NRG-1/ERBB4 pathway. It is already known that tyrosine 128 phosphorylation of ERBB4 is decreased in patients who have ALS-associated ERBB4 mutations. We generated ERBB4 N706D construct using site-directed mutagenesis and checked the phosphorylation level of ERBB4 N706D in NSC-34 cells. We found that the phosphorylation of ERBB4 N706D was decreased compared to ERBB4 wild-type, indicating a loss of function mutation in ERBB4. We report a novel variant in ERBB4 gene leading to ALS through dysfunction of ERBB4.

Engineering of cell-surface receptors for analysis of receptor internalization and detection of receptor-specific glycosylation

The epidermal growth factor receptor (EGFR) is a cell-surface glycoprotein that is involved mainly in cell proliferation. Overexpression of this receptor is intimately related to the development of a broad spectrum of tumors. In addition, glycans linked to the EGFR are known to affect its EGF-induced activation. Because of the pathophysiological significance of the EGFR, we prepared a fluorescently labeled EGFR (EGFR128-AZDye 488) on the cell surface by employing the genetic code expansion technique and bioorthogonal chemistry. EGFR128-AZDye 488 was initially utilized to investigate time-dependent endocytosis of the EGFR in live cells. The results showed that an EGFR inhibitor and antibody suppress endocytosis of the EGFR promoted by the EGF, and that lectins recognizing glycans of the EGFR do not enhance EGFR internalization into cells. Observations made in studies of the effects of appended glycans on the entry of the EGFR into cells indicate that a de-sialylated or de-fucosylated EGFR is internalized into cells more efficiently than a wild-type EGFR. Furthermore, by using the FRET-based imaging method of cells which contain an EGFR linked to AZDye 488 (a FRET donor) and cellular glycans labeled with rhodamine (a FRET acceptor), sialic acid residues attached to the EGFR were specifically detected on the live cell surface. Taken together, the results suggest that a fluorescently labeled EGFR will be a valuable tool in studies aimed at gaining an understanding of cellular functions of the EGFR.

Targeting the EGFR/RAS/RAF signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023)

INTRODUCTION

Recent years have seen significant strides in drug developmenttargeting the EGFR/RAS/RAF signaling pathway which is critical forcell growth and proliferation. Protein-protein interaction networksamong EGFR, RAS, and RAF proteins offer insights for drug discovery. This review discusses the drug design and development efforts ofinhibitors targeting these proteins over the past 3 years, detailingtheir structures, selectivity, efficacy, and combination therapy.Strategies to combat drug resistance and minimize toxicities areexplored, along with future research directions.

AREA COVERED

This review encompasses clinical trials and patents on EGFR, KRAS,and BRAF inhibitors from 2020 to 2023, including advancements indesign and synthesis of proteolysis targeting chimeras (PROTACs) forprotein degradation.

EXPERT OPINION

To tackle drug resistance, designing allosteric fourth-generationEGFR inhibitors is vital. Covalent, allosteric, or combinationaltherapies, along with PROTAC degraders, are key methods to addressresistance and toxicity in KRAS and BRAF inhibitors.

Intragenic EGFR::EGFR.E1E8 Fusion (EGFRvIII) in 4331 Solid Tumors

Epidermal growth factor receptor variant III (EGFRvIII, the deletion of exons 2-7) is a recurrent intragenic EGFR::EGFR.E1E8 fusion that occurs in high-grade gliomas. The presence of EGFRvIII in other solid tumors has not been well characterized. We retrospectively reviewed advanced malignant solid tumor cases tested by a custom hybrid capture 610-gene next-generation sequencing platform from 2021 to 2022. EGFRvIII was identified in 17 of 4331 (0.4%) cases, including 16 of 238 (7%) brain tumors and 1/301 (0.3%) breast tumors. EGFRvIII-positive brain tumors were all glioblastoma IDH-wildtype, most with concurrent TERT promoter mutation (14 of 16), EGFR amplification (13 of 16), and EGFR mutation (8 of 16). The only EGFRvIII-positive breast lesion was a sarcomatoid neoplasm in a young female patient. A separate breast case tested outside our institution with reported EGFRvIII was noted in a young female patient with a malignant phyllodes tumor with stromal overgrowth. Microscopically, both EGFRvIII-positive breast tumors showed high-grade sarcomatoid morphology with brisk mitotic activity. In summary, EGFRvIII is rare, occurring primarily in glioblastoma and rarely in breast sarcomatoid neoplasm, with no instances identified in other tumor types in our series. This select group of patients may benefit from chemotherapy and/or targeted anti-EGFR therapy.

Exploring the underlying mechanisms of fisetin in the treatment of hepatic insulin resistance via network pharmacology and in vitro validation

OBJECTIVE

To characterize potential mechanisms of fisetin on hepatic insulin resistance (IR) using network pharmacology and in vitro validation.

METHODS

Putative targets of fisetin were retrieved from the Traditional Chinese Medicine Systems Pharmacology database, whereas the potential genes of hepatic IR were obtained from GeneCards database. A protein-protein interaction (PPI) network was constructed according to the intersection targets of fisetin and hepatic IR using the Venn diagram. The biological functions and potential pathways related to genes were determined using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Cell experiments were also conducted to further verify the mechanism of fisetin on hepatic IR.

RESULTS

A total of 118 potential targets from fisetin were associated with hepatic IR. The areas of nodes and corresponding degree values of TP53, AKT1, TNF, IL6, CASP3, CTNNB1, JUN, SRC, epidermal growth factor receptor (EGFR), and HSP90AA1 were larger and could be easily found in the PPI network. Furthermore, GO analysis revealed that these key targets were significantly involved in multiple biological processes that participated in oxidative stress and serine/threonine kinase activity. KEGG enrichment analysis showed that the PI3K/AKT signaling pathway was a significant pathway involved in hepatic IR. Our in vitro results demonstrated that fisetin treatment increased the expressions of EGFR and IRS in HepG2 and L02 cells under normal or IR conditions. Western blot results revealed that p-AKT/AKT levels were significantly up-regulated, suggesting that fisetin was involved in the PI3K/AKT signaling pathway to regulate insulin signaling.

CONCLUSION

We explored the pharmacological actions and the potential molecular mechanism of fisetin in treating hepatic IR from a holistic perspective. Our study lays a theoretical foundation for the development of fisetin for type 2 diabetes.

Cell-active, irreversible covalent inhibitors that selectively target the catalytic lysine of EGFR by using fluorosulfate-based SuFEx chemistry

EGFR signaling is involved in multiple cellular processes including cell proliferation, differentiation and development, making this protein kinase one of the most valuable drug targets for the treatment of non-small cell lung carcinomas (NSCLC). Herein, we describe the design and synthesis of a series of potential covalent inhibitors targeting the catalytically conserved lysine (K745) of EGFR on the basis of Erlotinib, an FDA-approved first-generation EGFR drug. Different amine-reactive electrophiles were introduced at positions on the Erlotinib scaffold proximal to K745 in EGFR. The optimized compound 26 (as well as its close analog 30), possessing a novel arylfluorosulfate group (ArOSO2F), showed excellent in vitro potency (as low as 0.19 nM in independent IC50 determination) and selectivity against EGFR and many of its drug-resistant mutants. Both intact protein mass spectrometry (MS) and site-mapping analysis revealed that compound 26 covalently bound to EGFR at K745 through the formation of a sulfamate. In addition, compound 26 displayed good anti-proliferative potency against EGFR-overexpressing HCC827 cells by inhibiting endogenous EGFR autophosphorylation. The pharmacokinetic studies of compound 26 demonstrated the druggable potential of other ArOSO2F-containing compounds. Finally, competitive activity-based protein profiling (ABPP), cellular thermal shift assay (CETSA), as well as cellular wash-out experiments, all showed compound 26 to be the first cell-active, fluorosulfate-based targeted covalent inhibitor (TCI) of protein kinases capable of covalently engaging the catalytically conserved lysine of its target in live mammalian cells.

From signalling pathways to targeted therapies: unravelling glioblastoma's secrets and harnessing two decades of progress

Glioblastoma, a rare, and highly lethal form of brain cancer, poses significant challenges in terms of therapeutic resistance, and poor survival rates for both adult and paediatric patients alike. Despite advancements in brain cancer research driven by a technological revolution, translating our understanding of glioblastoma pathogenesis into improved clinical outcomes remains a critical unmet need. This review emphasises the intricate role of receptor tyrosine kinase signalling pathways, epigenetic mechanisms, and metabolic functions in glioblastoma tumourigenesis and therapeutic resistance. We also discuss the extensive efforts over the past two decades that have explored targeted therapies against these pathways. Emerging therapeutic approaches, such as antibody-toxin conjugates or CAR T cell therapies, offer potential by specifically targeting proteins on the glioblastoma cell surface. Combination strategies incorporating protein-targeted therapy and immune-based therapies demonstrate great promise for future clinical research. Moreover, gaining insights into the role of cell-of-origin in glioblastoma treatment response holds the potential to advance precision medicine approaches. Addressing these challenges is crucial to improving outcomes for glioblastoma patients and moving towards more effective precision therapies.

Recent advances in targeting the "undruggable" proteins: from drug discovery to clinical trials

Undruggable proteins are a class of proteins that are often characterized by large, complex structures or functions that are difficult to interfere with using conventional drug design strategies. Targeting such undruggable targets has been considered also a great opportunity for treatment of human diseases and has attracted substantial efforts in the field of medicine. Therefore, in this review, we focus on the recent development of drug discovery targeting "undruggable" proteins and their application in clinic. To make this review well organized, we discuss the design strategies targeting the undruggable proteins, including covalent regulation, allosteric inhibition, protein-protein/DNA interaction inhibition, targeted proteins regulation, nucleic acid-based approach, immunotherapy and others.

Involvement of the AKT Pathway in Resistance to Erlotinib and Cabozantinib in Triple-Negative Breast Cancer Cell Lines

Resistance to protein tyrosine kinase inhibitors (TKIs) presents a significant challenge in therapeutic target development for cancers such as triple-negative breast cancer (TNBC), where conventional therapies are ineffective at combatting systemic disease. Due to increased expression, the receptor tyrosine kinases EGFR (epidermal growth factor receptor) and c-Met are potential targets for treatment. However, targeted anti-EGFR and anti-c-Met therapies have faced mixed results in clinical trials due to acquired resistance. We hypothesize that adaptive responses in regulatory kinase networks within the EGFR and c-Met signaling axes contribute to the development of acquired erlotinib and cabozantinib resistance. To test this, we developed two separate models for cabozantinib and erlotinib resistance using the MDA-MB-231 and MDA-MB-468 cell lines, respectively. We observed that erlotinib- or cabozantinib-resistant cell lines demonstrate enhanced cell proliferation, migration, invasion, and activation of EGFR or c-Met downstream signaling (respectively). Using a SILAC (Stable Isotope Labeling of Amino acids in Cell Culture)-labeled quantitative mass spectrometry proteomics approach, we assessed the effects of erlotinib or cabozantinib resistance on the phosphoproteome, proteome, and kinome. Using this integrated proteomics approach, we identified several potential kinase mediators of cabozantinib resistance and confirmed the contribution of AKT1 to erlotinib resistance in TNBC-resistant cell lines.

Association of non-high-density lipoprotein cholesterol trajectories with the development of non-alcoholic fatty liver disease: an epidemiological and genome-wide association study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) shares common risk factors with cardiovascular diseases. Effects of longitudinal trends in non-high-density lipoprotein (non-HDL) cholesterol on NAFLD development are not understood. This study aimed to assess the relationship between non-HDL cholesterol trajectories and the incidence of NAFLD and to identify genetic differences contributing to NAFLD development between non-HDL cholesterol trajectory groups.

METHODS

We analyzed data from 2203 adults (aged 40-69 years) who participated in the Korean Genome and Epidemiology Study. During the 6-year exposure periods, participants were classified into an increasing non-HDL cholesterol trajectory group (n = 934) or a stable group (n = 1269). NAFLD was defined using a NAFLD-liver fat score > -0.640. Multiple Cox proportional hazard regression analysis estimated the hazard ratio (HR) and the 95% confidence interval (CI) for the incidence of NAFLD in the increasing group compared with the stable group.

RESULTS

A genome-wide association study identified significant single-nucleotide polymorphisms (SNPs) associated with NAFLD. During the median 7.8-year of event accrual period, 666 (30.2%) newly developed NAFLD cases were collected. Compared with the stable non-HDL group, the adjusted HR (95% CI) for the incidence of NAFLD in the increasing non-HDL cholesterol group was 1.46 (1.25-1.71). Although there were no significant SNPs, the polygenic risk score was highest in the increasing group, followed by the stable and control groups.

CONCLUSION

Our study indicates that lifestyle or environmental factors have a greater effect size than genetic factors in NAFLD progression risk. Lifestyle modification could be an effective prevention strategy for NAFLD for people with elevated non-HDL cholesterol.

Cisplatin-induced increase in heregulin 1 and its attenuation by the monoclonal ErbB3 antibody seribantumab in bladder cancer

Cisplatin-based combination chemotherapy is the foundation for treatment of advanced bladder cancer (BlCa), but many patients develop chemoresistance mediated by increased Akt and ERK phosphorylation. However, the mechanism by which cisplatin induces this increase has not been elucidated. Among six patient-derived xenograft (PDX) models of BlCa, we observed that the cisplatin-resistant BL0269 express high epidermal growth factor receptor, ErbB2/HER2 and ErbB3/HER3. Cisplatin treatment transiently increased phospho-ErbB3 (Y1328), phospho-ERK (T202/Y204) and phospho-Akt (S473), and analysis of radical cystectomy tissues from patients with BlCa showed correlation between ErbB3 and ERK phosphorylation, likely due to the activation of ERK via the ErbB3 pathway. In vitro analysis revealed a role for the ErbB3 ligand heregulin1-β1 (HRG1/NRG1), which is higher in chemoresistant lines compared to cisplatin-sensitive cells. Additionally, cisplatin treatment, both in PDX and cell models, increased HRG1 levels. The monoclonal antibody seribantumab, that obstructs ErbB3 ligand-binding, suppressed HRG1-induced ErbB3, Akt and ERK phosphorylation. Seribantumab also prevented tumor growth in both the chemosensitive BL0440 and chemoresistant BL0269 models. Our data demonstrate that cisplatin-associated increases in Akt and ERK phosphorylation is mediated by an elevation in HRG1, suggesting that inhibition of ErbB3 phosphorylation may be a useful therapeutic strategy in BlCa with high phospho-ErbB3 and HRG1 levels.

TMEM25 inhibits monomeric EGFR-mediated STAT3 activation in basal state to suppress triple-negative breast cancer progression

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor outcome and lacks of approved targeted therapy. Overexpression of epidermal growth factor receptor (EGFR) is found in more than 50% TNBC and is suggested as a driving force in progression of TNBC; however, targeting EGFR using antibodies to prevent its dimerization and activation shows no significant benefits for TNBC patients. Here we report that EGFR monomer may activate signal transducer activator of transcription-3 (STAT3) in the absence of transmembrane protein TMEM25, whose expression is frequently decreased in human TNBC. Deficiency of TMEM25 allows EGFR monomer to phosphorylate STAT3 independent of ligand binding, and thus enhances basal STAT3 activation to promote TNBC progression in female mice. Moreover, supplying TMEM25 by adeno-associated virus strongly suppresses STAT3 activation and TNBC progression. Hence, our study reveals a role of monomeric-EGFR/STAT3 signaling pathway in TNBC progression and points out a potential targeted therapy for TNBC.

A cell-based subtractive panning strategy for selection of conformation-specific single-chain variable-fragment (scFv) against dimerization domain of EGFR

BACKGROUND AND OBJECTIVE

Overexpression of EGFR, a member of the ErbB receptor family, has been observed in several cancers and causes resistance to therapeutic antibodies, such as Herceptin. In this study, we produced a recombinant single-chain variable fragment (scFv) antibody against the EGFR dimerization domain.

METHODS

The recombinant scFv was generated using a cell-based subtractive panning strategy. Subtractive panning was performed on a genetically engineered, VERO/EGFR, cells as well as a triple-negative breast cancer, MDA-MB-468, cells. Phage cell-ELISA was used to monitor the binding of the selected scFvs to the dimerization domain of EGFR. Inhibition of EGFR and HER2 dimerization by the produced scFvs were finally evaluated using the dimerization inhibition test and the expression of apoptosis-related genes were measured using the quantitative RT-PCR.

RESULTS

PCR fingerprinting results showed a uniform digestion pattern following the third round of panning that confirmed the success of subtractive panning. Moreover, cell-ELISA validated the reactivity of the produced scFvs to EGFR following stimulation with EGF. Dimerization inhibition test showed the capacity of the scFvs to inhibit EGFR and HER2 dimerization. Investigation of apoptosis-related genes showed that treatment with the scFv antibody caused increased Bax and decreased Bcl2 expression.

CONCLUSIONS

Directed HER2 targeting was shown to be effective enough to block the functional domain of the cell receptor and its intracellular signaling pathway. The subtractive panning strategy used in this study could control the process of directed selection of specific antibodies against the dimerization domain of EGFR. Selected antibodies might then be functionally tested for antitumor effects in both in vitro and in vivo studies.

Small Molecule EGFR Inhibitors as Anti-Cancer Agents: Discovery, Mechanisms of Action, and Opportunities

Epidermal growth factor receptors (EGFRs) are a class of receptor tyrosine kinase that are also called ErbB1 and HER1. EGFR tyrosine kinase activity inhibition is considered a promising therapeutic strategy for the treatment of cancer. Many small-molecule inhibitors of EGFR tyrosine kinase (EGFR-TK), from medicinally privileged molecules to commercial drugs, have been overviewed. Particular attention has been paid to the structure of the molecule and its mechanism of action if reported. Subsequent classification of the molecules under discussion has been carried out. Both natural and synthetic and reversible and irreversible EGFR-tyrosine kinase inhibitors have been discussed. Various types of cancers that are caused by overexpression of the EGFR gene, their possible molecular origins, and their natures have also been counted in this article. Because the EGFR signaling pathway controls the proliferation, growth, survival, and differentiation of cells, and the mutated EGFR gene overproduces EGFR protein, which ultimately causes several types of cancer, proper understanding of the molecular dynamics between the protein structure and its inhibitors will lead to more effective and selective EGFR-TKIs, which in turn will be able to save more lives in the battle against cancer.

Investigating the clinical significance of EGFR expression using machine learning in a series of Iraqi patients with triple-negative breast cancer

Breast cancer is a heterogeneous disease with a distinct profile of the expression of each tumor. Triple-negative breast cancer (TNBC) is a molecular subtype of breast cancer characterized by an aggressive clinical behavior linked to loss or reduced expression of estrogen, progesterone, and Her2/neu receptors. The study's main objective was to investigate the clinical significance of epidermal growth factor receptor (EGFR) overexpression in a series of Iraqi patients with TNBC. The sectional analytic study involved immunohistochemical analysis of EGFR expression in randomly selected 53 formalin fixed paraffin embedded tissue blocks of TNBC cases out of 127 Iraqi patients with TNBC and correlated expression data with clinicopathological parameters including survival time. Machine learning (statistical tests and principal component analysis (PCA)) was used to predict the outcome of the patients using EGFR expression data together with clinicopathological parameters. EGFR was expressed in approximately 28% of TNBC cases. We estimated the risk of mortality and distant metastasis based on EGFR expression and clinicopathologic factors using the principal component analysis (PCA) model. We found a substantial positive correlation between clinical stage and distant metastasis, clinical stage and death, death and distant metastasis, and death and positive EGFR expression. Overall, EGFR expression was linked to a poor prognosis and increased mortality. A higher risk of distant metastasis and death was associated with an advanced clinical stage of the tumor. Furthermore, the existence of distant metastases increased the risk of death. These findings raise the possibility of using EGFR expression data with other clinicopathological parameters to predict the outcome of patients with TNBC.

Wnt Signaling in the Breast: From Development to Disease

The Wnt cascade is a primordial developmental signaling pathway that plays a myriad of essential functions throughout development and adult homeostasis in virtually all animal species. Aberrant Wnt activity is implicated in embryonic and tissue morphogenesis defects, and several diseases, most notably cancer. The role of Wnt signaling in mammary gland development and breast cancer initiation, maintenance, and progression is far from being completely understood and is rather shrouded in controversy. In this review, we dissect the fundamental role of Wnt signaling in mammary gland development and adult homeostasis and explore how defects in its tightly regulated and intricated molecular network are interlinked with cancer, with a focus on the breast.

Analysis of ERBB4 Variants in Amyotrophic Lateral Sclerosis Within a Chinese Cohort

ERBB4 is related to amyotrophic lateral sclerosis (ALS) in patients with a family history and is thought to cause ALS-19. We screened 448 ALS patients, including 364 sporadic ALS (sALS) and 84 familial ALS (fALS) patients with ERBB4 variants, in a Chinese cohort. In total, 12 missense variants were identified in this study. Of these, 3 (p.Arg106His, p.Gln164Pro, and p.Val212Leu) were absent from the in-house healthy control cohort and population databases and predicted to be likely pathogenic. Genetic burden analysis did not reveal an increase in damaging variants of the ERBB4 gene. We considered that most of the missense variants in ERBB4 were not pathogenic, but certain variants, such as p.Arg106His, p.Gln164Pro, and p.Val212Leu, were likely pathogenic. The phenotype of these three patients carrying ERBB4 variants revealed the typical clinical manifestations of ALS without cognitive dysfunction. We concluded that ERBB4 likely pathogenic variants account for ~0.67% of ALS patients in China. It is necessary to interpret the relationship between the disease and variants carefully for ALS patients with ERBB4 gene variants.

Negative regulation of receptor tyrosine kinases by ubiquitination: Key roles of the Cbl family of E3 ubiquitin ligases

Receptor tyrosine kinases (RTKs) serve as transmembrane receptors that participate in a broad spectrum of cellular processes including cellular growth, motility, differentiation, proliferation, and metabolism. Hence, elucidating the regulatory mechanisms of RTKs involved in an assortment of diseases such as cancers attracts increasing interest from researchers. Members of the Cbl family ubiquitin ligases (c-Cbl, Cbl-b and Cbl-c in mammals) have emerged as negative regulators of activated RTKs. Upon activation of RTKs by growth factors, Cbl binds to RTKs via its tyrosine kinase binding (TKB) domain and targets them for ubiquitination, thus facilitating their degradation and negative regulation of RTK signaling. RTKs such as epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGF), fibroblast growth factor receptor (FGFR) and hepatocyte growth factor receptor (HGFR) undergo ubiquitination upon interaction with Cbl family members. In this review, we summarize the current knowledge related to the negative regulation of RTKs by Cbl family proteins.

The Yin and Yang of ERBB4: Tumor Suppressor and Oncoprotein

ERBB4 (HER4) is a member of the ERBB family of receptor tyrosine kinases, a family that includes the epidermal growth factor receptor (EGFR/ERBB1/HER1), ERBB2 (Neu/HER2), and ERBB3 (HER3). EGFR and ERBB2 are oncoproteins and validated targets for therapeutic intervention in a variety of solid tumors. In contrast, the role that ERBB4 plays in human malignancies is ambiguous. Thus, here we review the literature regarding ERBB4 function in human malignancies. We review the mechanisms of ERBB4 signaling with an emphasis on mechanisms of signaling specificity. In the context of this signaling specificity, we discuss the hypothesis that ERBB4 appears to function as a tumor suppressor protein and as an oncoprotein. Next, we review the literature that describes the role of ERBB4 in tumors of the bladder, liver, prostate, brain, colon, stomach, lung, bone, ovary, thyroid, hematopoietic tissues, pancreas, breast, skin, head, and neck. Whenever possible, we discuss the possibility that ERBB4 mutants function as biomarkers in these tumors. Finally, we discuss the potential roles of ERBB4 mutants in the staging of human tumors and how ERBB4 function may dictate the treatment of human tumors. SIGNIFICANCE STATEMENT: This articles reviews ERBB4 function in the context of the mechanistic model that ERBB4 homodimers function as tumor suppressors, whereas ERBB4-EGFR or ERBB4-ERBB2 heterodimers act as oncogenes. Thus, this review serves as a mechanistic framework for clinicians and scientists to consider the role of ERBB4 and ERBB4 mutants in staging and treating human tumors.

Liver regeneration biology: Implications for liver tumour therapies

The liver has remarkable regenerative potential, with the capacity to regenerate after 75% hepatectomy in humans and up to 90% hepatectomy in some rodent models, enabling it to meet the challenge of diverse injury types, including physical trauma, infection, inflammatory processes, direct toxicity, and immunological insults. Current understanding of liver regeneration is based largely on animal research, historically in large animals, and more recently in rodents and zebrafish, which provide powerful genetic manipulation experimental tools. Whilst immensely valuable, these models have limitations in extrapolation to the human situation. In vitro models have evolved from 2-dimensional culture to complex 3 dimensional organoids, but also have shortcomings in replicating the complex hepatic micro-anatomical and physiological milieu. The process of liver regeneration is only partially understood and characterized by layers of complexity. Liver regeneration is triggered and controlled by a multitude of mitogens acting in autocrine, paracrine, and endocrine ways, with much redundancy and cross-talk between biochemical pathways. The regenerative response is variable, involving both hypertrophy and true proliferative hyperplasia, which is itself variable, including both cellular phenotypic fidelity and cellular trans-differentiation, according to the type of injury. Complex interactions occur between parenchymal and non-parenchymal cells, and regeneration is affected by the status of the liver parenchyma, with differences between healthy and diseased liver. Finally, the process of termination of liver regeneration is even less well understood than its triggers. The complexity of liver regeneration biology combined with limited understanding has restricted specific clinical interventions to enhance liver regeneration. Moreover, manipulating the fundamental biochemical pathways involved would require cautious assessment, for fear of unintended consequences. Nevertheless, current knowledge provides guiding principles for strategies to optimise liver regeneration potential.

Wound Healing Effect of Gintonin Involves Lysophosphatidic Acid Receptor/Vascular Endothelial Growth Factor Signaling Pathway in Keratinocytes

Gintonin, a novel compound of ginseng, is a ligand of the lysophosphatidic acid (LPA) receptor. The in vitro and in vivo skin wound healing effects of gintonin remain unknown. Therefore, the objective of this study was to investigate the effects of gintonin on wound healing-linked responses, especially migration and proliferation, in skin keratinocytes HaCaT. In this study, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay, Boyden chamber migration assay, scratch wound healing assay, and Western blot assay were performed. A tail wound mouse model was used for the in vivo test. Gintonin increased proliferation, migration, and scratch closure in HaCaT cells. It also increased the release of vascular endothelial growth factor (VEGF) in HaCaT cells. However, these increases, induced by gintonin, were markedly blocked by treatment with Ki16425, an LPA inhibitor, PD98059, an ERK inhibitor, 1,2-Bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis (acetoxymethyl ester), a calcium chelator, and U73122, a PLC inhibitor. The VEGF receptor inhibitor axitinib also attenuated gintonin-enhanced HaCaT cell proliferation. Gintonin increased the phosphorylation of AKT and ERK1/2 in HaCaT cells. In addition, gintonin improved tail wound healing in mice. These results indicate that gintonin may promote wound healing through LPA receptor activation and/or VEGF release-mediated downstream signaling pathways. Thus, gintonin could be a beneficial substance to facilitate skin wound healing.

Defucosylated Anti-Epidermal Growth Factor Receptor Monoclonal Antibody 134-mG2a-f Exerts Antitumor Activities in Mouse Xenograft Models of Dog Epidermal Growth Factor Receptor-Overexpressed Cells

The epidermal growth factor receptor (EGFR) is a type I transmembrane protein, which is a member of the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases. EGFR is a crucial mediator of cell growth and differentiation and forms homodimers or heterodimers with other HER family members to activate downstream signaling cascades. We previously established an anti-human EGFR (hEGFR) monoclonal antibody (mAb), clone EMab-134 (mouse IgG₁), by immunizing mice with the ectodomain of hEGFR. In this study, the subclass of EMab-134 was converted from IgG₁ to IgG_2a (134-mG_2a) and further defucosylated (134-mG_2a-f) to facilitate antibody-dependent cellular cytotoxicity (ADCC). Although 134-mG_2a-f was developed against hEGFR, it was shown to cross-react with dog EGFR (dEGFR) using flow cytometry. The dissociation constant (K_D) of 134-mG_2a-f against dEGFR-overexpressed CHO-K1 (CHO/dEGFR) cells was determined by flow cytometry to be 3.3 × 10^-9 M, indicating that 134-mG_2a-f possesses a high binding affinity to dEGFR. Analysis in vitro revealed that 134-mG_2a-f contributed to high levels of ADCC and complement-dependent cytotoxicity (CDC) in experiments targeting CHO/dEGFR cells. Furthermore, the in vivo administration of 134-mG_2a-f significantly inhibited the development of CHO/dEGFR in comparison with the results observed in response to control mouse IgG. Taken together, the findings of this study demonstrate that 134-mG_2a-f could be useful as part of a therapeutic regimen for dEGFR-expressing canine cancers.

Stimulation of the four isoforms of receptor tyrosine kinase ErbB4, but not ErbB1, confers cardiomyocyte hypertrophy

Epidermal growth factor (EGF) receptors (ErbB1-ErbB4) promote cardiac development and growth, although the specific EGF ligands and receptor isoforms involved in growth/repair versus pathology remain undefined. We challenged ventricular cardiomyocytes with EGF-like ligands and observed that selective activation of ErbB4 (the receptor for neuregulin 1 [NRG1]), but not ErbB1 (the receptor for EGF, EGFR), stimulated hypertrophy. This lack of direct ErbB1-mediated hypertrophy occurred despite robust activation of extracellular-regulated kinase 1/2 (ERK) and protein kinase B. Hypertrophic responses to NRG1 were unaffected by the tyrosine kinase inhibitor (AG1478) at concentrations that are selective for ErbB1 over ErbB4. NRG1-induced cardiomyocyte enlargement was suppressed by small interfering RNA (siRNA) knockdown of ErbB4 and ErbB2, whereas ERK phosphorylation was only suppressed by ErbB4 siRNA. Four ErbB4 isoforms exist (JM-a/JM-b and CYT-1/CYT-2), generated by alternative splicing, and their expression declines postnatally and following cardiac hypertrophy. Silencing of all four isoforms in cardiomyocytes, using an ErbB4 siRNA, abrogated NRG1-induced hypertrophic promoter/reporter activity, which was rescued by coexpression of knockdown-resistant versions of the ErbB4 isoforms. Thus, ErbB4 confers cardiomyocyte hypertrophy to NRG1, and all four ErbB4 isoforms possess the capacity to mediate this effect.

Analysis of Increased EGFR and IGF-1R Signaling and Its Correlation with Socio-Epidemiological Features and Biological Profile in Breast Cancer Patients: A Study in Northern Brazil

INTRODUCTION

Breast cancer (BC) is the second most frequent cancer worldwide. It is known that a subset of BC has amplification, and overexpression of the epidermal growth factor receptor (EGFR) and high expression of the insulin-like growth factor receptor-1 (IGF-1R) are correlated with a favorable prognosis. This study aimed to evaluate the prognostic and predictive values of the EGFR and IGF-1R in tumor samples from patients with BC and their correlation with socio-epidemiological features.

PATIENTS AND METHODS

We analyzed socio-epidemiological, clinical-pathological data and tumor tissues from 124 patients with BC undergoing treatment, to assess levels of EGFR and IGF-1R mRNA and protein. The predictive performance included the calculation of area-under-the-curve (AUC) to discriminate groups of patients with high and low mRNA expression associated with survival analysis within each molecular group of BC.

RESULTS

We found a significant expression increase (p <0.001) in EGFR associated with body mass index, angiolymphatic invasion, compromised lymph nodes and follow-up in 58.1% of the triple-negative and HER overexpression tumors. The increase in IGF-IR was significant (p <0.001) in 41.9% of luminal tumors A and B. ROC analysis showed that EGFR had a higher predictive performance (AUC = 0.891) than IGF-1R (AUC = 0.60). The Kaplan-Meier analysis indicated that only the high expression of EGFR was associated with a decreased probability of survival for patients, what did not happen with IGF-1R.

CONCLUSION

Our results suggest that EGFR and IGF-1R expression patterns associated with the clinical characteristics of patients and biological profile influenced the evolution of BC.

Bortezomib induces methylation changes in neuroblastoma cells that appear to play a significant role in resistance development to this compound

The anticancer activity of bortezomib (BTZ) has been increasingly studied in a number of indications and promising results for the use of this treatment have been shown in neuroblastoma. As BTZ treatment is usually administered in cycles, the development of resistance and side effects in patients undergoing therapy with BTZ remains a major challenge for the clinical usage of this compound. Common resistance development also means that certain cells are able to survive BTZ treatment and bypass molecular mechanisms that render BTZ anticancer activity. We studied the methylome of neuroblastoma cells that survived BTZ treatment. Our results indicate that BTZ induces pronounced genome wide methylation changes in cells which recovered from the treatment. Functional analyses of identified methylation changes demonstrated they were involved in key cancer pathology pathways. These changes may allow the cells to bypass the primary anticancer activity of BTZ and develop a treatment resistant and proliferative phenotype. To study whether cells surviving BTZ treatment acquire a proliferative phenotype, we repeatedly treated cells which recovered from the first round of BTZ treatment. The repetitive treatment led to induction of the extraordinary proliferative potential of the cells, that increased with subsequent treatments. As we did not observe similar effects in cells that survived treatment with lenalidomide, and non-treated cells cultured under the same experimental conditions, this phenomenon seems to be BTZ specific. Overall, our results indicate that methylation changes may play major role in the development of BTZ resistance.

Keeping abreast about ashwagandha in breast cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Ashwagandha has been used as an ayurvedic medicine in the form of 'Rasayana' (as a tonic) even before 3000 BCE in India. As per Ayurveda, it has long been used traditionally for the treatment of inflammation, weakness, impotence, pulmonary tuberculosis. This plant is also beneficial in lumbago and leucorrhea in the female. In the recent past, Withania has shown its anti-cancerous activity in various experimental models. In addition, Withania also possesses many other properties such as anti-oxidant, anti-stress, adaptogenic, and regenerative which will eventually be beneficial and safe in treating cancer patients.

AIM OF THE STUDY

This review aims to provide experimental evidence along with a deeper insight into molecular mechanisms of Ashwagandha (Withania somnifera (L.) Dunal) through which it acts as a chemotherapeutic agent against different types of breast cancer.

MATERIALS AND METHODS

Literature searches with the help of electronic online databases (Elsevier, Google Scholar, Scopus, Springer Link, ScienceDirect, ResearchGate, PubMed) were carried out. The timeline for collection of data for the review article was from 2000 to 2019. The plant name was validated from The Plant List (2013). Version 1.1. Published on http://www.theplantlist.org/(accessed 21st March 2020).

RESULTS

Various forms of Withania somnifera were used and several in vitro, in vivo, and clinical studies were reported by researchers. They found ashwagandha to exhibit anti-apoptotic, anti-metastatic, anti-invasive and anti-inflammatory properties and gave the evidence that ashwagandha has a capability for averting and treating breast cancer.

CONCLUSION

Various in vitro and in vivo studies suggested Ashwagandha may possess a potential for treating breast cancer, especially ER/PR positive breast cancer and triple-negative breast cancer. A clinical trial has also been conducted in the past that suggested its potential in refining quality of life in breast cancer patients. Studies directed towards molecular pathways have helped in unravelling the key mechanisms of ashwagandha. Future research should be directed towards translational studies involving breast cancer patients. These will reinforce the ancient power of our Ayurvedic medicine.

Landscape of somatic mutations in breast cancer: new opportunities for targeted therapies in Saudi Arabian patients

Breast cancer (BCa) ranks first in incidence rate among cancers in Arab females. The association between genetic polymorphisms in tumor suppressor genes and the risk of BCa has been studied in many ethnic populations with conflicting conclusions while Arab females and Saudi Arabian studies are still lacking. We screened a cohort of Saudi BCa patients by NGS using a bespoke gene panel to clarify the genetic landscape of this population, correlating and assessing genetic findings with clinical outcomes. We identified a total of 263 mutations spanning 51 genes, including several frequently mutated. Among the genes analyzed, the highest mutation rates were found in PIK3CA (12.9%), BRCA2 (11.7%), BRCA1 (10.2%), TP53 (6.0%), MSH2 (3.8%), PMS2 (3.8%), BARD1 (3.8%), MLH1 (3.4%), CDH1 (3.0%), RAD50 (3.0%), MSH6 (3.0%), NF1 (2.6%), in addition to others. We identified multiple common recurrent variants and previously reported mutations. We also identified 46 novel variants in 22 genes that were predicted to have a pathogenic effect. Survival analysis according to the four most common mutations (BRCA1, BRCA2, TP53, and PIK3CA) showed reduced survival in BRCA1 and BRCA2-mutant patients compared to total patients. Moreover, BRCA2 was demonstrated as an independent predictor of reduced survival using independent Cox proportional hazard models.

We reveal the landscape of the mutations associated with BCa in Saudi women, highlighting the importance of routine genetic sequencing in implementation of precision therapies in KSA.

Receptor Tyrosine Kinase Signaling and Targeting in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is amongst the deadliest of human cancers, with a median survival rate of just over one year following diagnosis. Characterized by rapid proliferation and diffuse infiltration into the brain, GBM is notoriously difficult to treat, with tumor cells showing limited response to existing therapies and eventually developing resistance to these interventions. As such, there is intense interest in better understanding the molecular alterations in GBM to guide the development of more efficient targeted therapies. GBM tumors can be classified into several molecular subtypes which have distinct genetic signatures, and they show aberrant activation of numerous signal transduction pathways, particularly those connected to receptor tyrosine kinases (RTKs) which control glioma cell growth, survival, migration, invasion, and angiogenesis. There are also non-canonical modes of RTK signaling found in GBM, which involve G-protein-coupled receptors and calcium channels. This review uses The Cancer Genome Atlas (TCGA) GBM dataset in combination with a data-mining approach to summarize disease characteristics, with a focus on select molecular pathways that drive GBM pathogenesis. We also present a unique genomic survey of RTKs that are frequently altered in GBM subtypes, as well as catalog the GBM disease association scores for all RTKs. Lastly, we discuss current RTK targeted therapies and highlight emerging directions in GBM research.

The Effect of the EGFR - Targeting Compound 3-[(4-Phenylpyrimidin-2-yl) Amino] Benzene-1-Sulfonamide (13f) against Cholangiocarcinoma Cell Lines

OBJECTIVE

Cholangiocarcinoma (CCA) is a noxious malignancy of epithelium of the bile duct with a low response rate to chemotherapy. The epidermal growth factor receptor (EGFR) signaling pathway is implicated in the development of cancerous cells, especially CCA. In this study, we report detailed biological profiling of 13f identified from our earlier hit expansion studies. The aim of this work was to expand our understanding of 13f via more detailed investigations of its mechanism of action against KKU-100, KKU-452 and KKU-M156 CCA cells, as well as in comparison to the EGFR inhibitor Gefitinib and non-specific chemotherapeutic agents such as Cisplatin.

METHODS

Inhibiting EGFR-Kinase, cytotoxicity, clonogenic assay, wound healing and apoptosis were performed. Levels of total expression of EGFR and EGFR phosphorylation proteins were detected.

RESULTS

13f was confirmed as an inhibitor of EGFR with an IC50 value against the tyrosine kinase of EGFR of 22 nM and IC50 values for 48 h incubation period were 1.3 ± 1.9, 1.5 ± 0.4 and 1.7 ± 1.1 µM of KKU-100, KKU-452 and KKU-M156, respectively through dose- and time-dependent induction of early apoptosis of CCA cells. The compound also suppressed the clonogenic ability of KKU-100 and KKU-M156 cells stronger than Gefitinib, while potently inhibiting EGF-stimulated CCA cell migratory activity in KKU-452 cells. It was observed that under normal conditions EGFR was activated in CCA cells. EGF-stimulated basal expression of EGFR in KKU-452 cells was suppressed following 13f treatment, which was significantly greater than that of the marketed EGFR inhibitor Gefitinib.

CONCLUSION

In summary, our study showed that 13f has potent anti-cancer activities including antiproliferation, clonogenic ability and migration through the modulation of EGFR signaling pathway in CCA for the first time. The compound represents an interesting starting point as a potential chemotherapeutic agent in ongoing efforts to improve response rate in CCA patients.<br />.

Review on Epidermal Growth Factor Receptor (EGFR) Structure, Signaling Pathways, Interactions, and Recent Updates of EGFR Inhibitors

The epidermal growth factor receptor (EGFR) belongs to the ERBB family of tyrosine kinase receptors. EGFR signaling cascade is a key regulator in cell proliferation, differentiation, division, survival, and cancer development. In this review, the EGFR structure and its mutations, signaling pathway, ligand binding and EGFR dimerization, EGF/EGFR interaction, and the progress in the development of EGFR inhibitors have been explored.

Pseudomonas Exotoxin A Based Toxins Targeting Epidermal Growth Factor Receptor for the Treatment of Prostate Cancer

The epidermal growth factor receptor (EGFR) was found to be a valuable target on prostate cancer (PCa) cells. However, EGFR inhibitors mostly failed in clinical studies with patients suffering from PCa. We therefore tested the targeted toxins EGF-PE40 and EGF-PE24mut consisting of the natural ligand EGF as binding domain and PE40, the natural toxin domain of Pseudomonas Exotoxin A, or PE24mut, the de-immunized variant thereof, as toxin domains. Both targeted toxins were expressed in the periplasm of E.coli and evoked an inhibition of protein biosynthesis in EGFR-expressing PCa cells. Concentration- and time-dependent killing of PCa cells was found with IC50 values after 48 and 72 h in the low nanomolar or picomolar range based on the induction of apoptosis. EGF-PE24mut was found to be about 11- to 120-fold less toxic than EGF-PE40. Both targeted toxins were more than 600 to 140,000-fold more cytotoxic than the EGFR inhibitor erlotinib. Due to their high and specific cytotoxicity, the EGF-based targeted toxins EGF-PE40 and EGF-PE24mut represent promising candidates for the future treatment of PCa.

CRISPR-Cas deployment in non-small cell lung cancer for target screening, validations, and discoveries

Continued advancements in CRISPR-Cas systems have accelerated genome research. Use of CRISPR-Cas in cancer research has been of great interest that is resulting in development of orthogonal methods for drug target validations and discovery of new therapeutic targets through genome-wide screens of cancer cells. CRISPR-based screens have also revealed several new cancer drivers through alterations in tumor suppressor genes (TSGs) and oncogenes inducing resistance to targeted therapies via activation of alternate signaling pathways. Given such dynamic status of cancer, we review the application of CRISPR-Cas in non-small cell lung cancer (NSCLC) for development of mutant models, drug screening, target validation, novel target discoveries, and other emerging potential applications. In addition, CRISPR-based approach for development of novel anticancer combination therapies is also discussed in this review.

Mechanisms of EGFR Resistance in Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite numerous efforts to target epidermal growth factor receptor (EGFR), commonly dysregulated in GBM, approaches directed against EGFR have not achieved the same degree of success as seen in other tumor types, particularly as compared to non-small cell lung cancer (NSCLC). EGFR alterations in glioblastoma lie primarily in the extracellular domain, unlike the kinase domain alterations seen in NSCLC. Small molecule inhibitors are difficult to develop for the extracellular domain. Monoclonal antibodies can be developed to target the extracellular domain but must contend with the blood brain barrier (BBB). We review the role of EGFR in GBM, the history of trialed treatments, and the potential paths forward to target the pathway that may have greater success.

Identification of a novel anti-EGFR nanobody by phage display and its distinct paratope and epitope via homology modeling and molecular docking

Since EGFR is an important and effective target for tumor therapy in the clinic. Several monoclonal antibodies and nanobodies were proved to target domain III of EGFR. Regarding the increased attention on nanobodies, the present study aimed to generate nanobodies specifically against domain III. After camel immunization, a gene repertoire of sdAb fragments with a diversity of 3×10⁹ clones was produced. Following the construction of two sdAb phage display libraries, the successful epitope binning was carried out to identify the nanobody with the designated epitope. Modelling of the identified nanobody and molecular docking studies illustrated the paratope and epitope. Docking analysis revealed that the paratope focused on CDR2 loop of the identified nanobody. The identified nanobody potently cover part of the epitope of Matuzumab and Nb 9G8, which indicated that it blocked EGFR by preventing dimerization of the receptors.

Predicting the Molecular Mechanism of EGFR Domain II Dimer Binding Interface by Machine Learning to Identify Potent Small Molecule Inhibitor for Treatment of Cancer

Epidermal growth factor receptor (EGFR) is a transmembrane druggable target controlling cellular differentiation, proliferation, migration, survival and invasion. EGFR activation mainly occurs by its homo/hetro dimerization molecular phenomenon leading to tumor development and invasion. Several tyrosine kinase based inhibitors were discovered as potent anti-cancer drugs. However, mutations in its kinase domain confer resistance to most of these drugs. To overcome this drug resistance, development of small molecule inhibitors disrupting the EGFR Domain II dimer binding by machine learning methods are promising. Based on this insight, a structure-based drug repurposing strategy was adopted to repurpose the existing FDA approved drugs in blocking the EGFR Domain II mediated dimerization. We identified five best repurposed drug molecules showing good binding affinity at its key arm-cavity dimer interface residues by different machine learning methods. The molecular mechanisms of action of these repurposed drugs were computationally validated by molecular electrostatics potential mapping, point mutations at the dimer arm-cavity binding interface, molecular docking and receptor interaction studies. The present machine learning strategy thus forms the basis of identifying potent and putative small molecule drugs for the treatment of different types of cancer.

Processing Temporal Growth Factor Patterns by an Epidermal Growth Factor Receptor Network Dynamically Established in Space

The proto-oncogenic epidermal growth factor (EGF) receptor (EGFR) is a tyrosine kinase whose sensitivity and response to growth factor signals that vary over time and space determine cellular behavior within a developing tissue. The molecular reorganization of the receptors on the plasma membrane and the enzyme-kinetic mechanisms of phosphorylation are key determinants that couple growth factor binding to EGFR signaling. To enable signal initiation and termination while simultaneously accounting for suppression of aberrant signaling, a coordinated coupling of EGFR kinase and protein tyrosine phosphatase activity is established through space by vesicular dynamics. The dynamical operation mode of this network enables not only time-varying growth factor sensing but also adaptation of the response depending on cellular context. By connecting spatially coupled enzymatic kinase/phosphatase processes and the corresponding dynamical systems description of the EGFR network, we elaborate on the general principles necessary for processing complex growth factor signals.

New Entrants into Clinical Trials for Targeted Therapy of Breast Cancer: An Insight

Breast cancer is too complex with various different molecular alterations involved in its pathogenesis and progression. Over the decade, we have seen a surge in the development of drugs for bimolecular targets and for the signal transduction pathways involved in the treatment line of breast cancer. These drugs, either alone or in combination with conventional treatments like chemotherapy, hormone therapy and radiotherapy, will help oncologists to get a better insight and do the needful treatment. These novel therapies bring various challenges along with them, which include the dosage selection, patient selection, schedule of treatment and weighing of clinical benefits over side effects. In this review, we highlight the recently studied target molecules that have received indications in breast carcinoma, both in the localized and in an advanced state and about their inhibitors which are in clinical development which can give the immense potential to clinical care in the near future.

Theoretical evaluation of EGFR kinase inhibition and toxicity of di-indol-3-yl disulphides with anti-cancer potency

Research aimed at developing potent di-indol-3-yl disulphides for cancer diseases makes use of various theoretical techniques to evaluate the drug-likeness parameters and the mode of action. A drug-likeness filter helps evaluate the therapeutic potency of four bis-indole derivatives, structurally related to 3,3'-methanediyl-bis-indole (DIM) but having the S-S instead of the methylene linker and showing a high inhibitory impact on the variants of cancer cell lines (among them HL-60 and DU-145). Based on in vitro experimental results for their close analogues, a correlation was found between the epidermal growth factor receptor kinase (EGFR) inhibition and the theoretical energy of complexation. Docking studies of ligands followed by molecular dynamics were performed at the ATP-binding site of EGFR tyrosine kinase to scrutinize the inhibition of the di-indol-3-yl disulphides at a molecular level. Derivatives with bromine or iodine substituents at C-5 positions of the indole moieties made strong complexes by interaction with the most important hinge region residues Met-793 and Cys-733. The inhibition model for EGFR kinase and the proposed procedures can be very informative in the biological testing of selected bis-indoles and may be useful for future research on effective inhibitors for the treatment of EGFR-related cancer.Communicated by Ramaswamy H. Sarma.

Subcellular distribution and mechanism of action of AL906, a novel and potent EGFR inhibitor rationally designed to be green fluorescent

To enhance the potency of EGFR inhibitors, we developed a novel strategy that seeks to conjugate EGFR to a bioactive moiety leading to a molecule termed "combi-molecule". In order to mimic the penetration of this type of molecules, based upon previously reported structure activity relationship studies, we designed a new molecule containing a quinazoline moiety tethered to a p-nitrobenzoxadiazole (NBD) moiety [molecular weight (MW) 700]. Despite its size, AL906 growth inhibitory activity was superior to that of the clinical drug gefitinib. Furthermore, AL906 retained significant EGFR inhibitory activity and good cellular penetration with abundant distribution in the perinuclear region of the cells. In an isogenic NIH3T3 transfected cell panel, it selectively inhibited the growth  of the NIH3T3-EGFR and HER2 transfectants. Confocal microscopy analysis revealed that it was capable of penetrating multilayer aggregates although to a lesser extent than FD105, a small inhibitor of EGFR inhibitor of the same class (MW 300). Its ability to inhibit EGFR auto-phosphorylation in monolayer culture was stronger than in the aggregates. The results suggest that our strategy did not negatively affect EGFR inhibitory potency, EGFR selectivity and growth inhibition. However, its molecular size may account for its decreased aggregate penetration when compared with a smaller EGFR inhibitor of the quinazoline class.

Cell Growth Stimulation, Cell Cycle Alternation, and Anti-Apoptosis Effects of Bovine Bone Collagen Hydrolysates Derived Peptides on MC3T3-E1 Cells Ex Vivo

Bovine bone collagen hydrolysates promote bone formation through regulating bone growth. However, the peptide sequences within these isolates have not been characterized. In this study, twenty-nine peptides from bovine bone collagen hydrolysates were purified and identified using nano-HPLC-MS-MS and Peak Studio analysis. HHGDQGAPGAVGPAGPRGPAGPSGPAGKDGR (Deamidation) and GPAGANGDRGEAGPAGPAGPAGPR (Deamidation) enhanced cell viability, inhibited apoptosis, and significantly altered the cell cycle of MC3T3-E1 osteoblast cells. These peptides were selected to perform molecular docking analysis to examine the mechanism underlying these bioactivities. Molecular docking analysis showed that these two peptides formed hydrophobic interactions and hydrogen bonds with epidermal growth factor receptor (EGFR) to activate the EGFR-signaling pathway, which may explain their bioactivity. These findings indicate that these and other similar peptides might be candidates for the treatment of osteoporosis.

Signal Transduction Pathways in Breast Cancer: The Important Role of PI3K/Akt/mTOR

Breast cancer is the cancer with the highest prevalence in women and is the number-one cause of cancer mortality worldwide. Cell transduction is a fundamental process in the development and progression of cancer. Modifications in various cell signalling pathways promote tumour cell proliferation, progression, and survival. The PI3K/Akt/mTOR pathway is an example of that, and it is involved in growth, proliferation, survival, motility, metabolism, and immune response regulation. Activation of this pathway is one of the main causes of cancer cell resistance to antitumour therapies. This makes PI3K/Akt/mTOR signalling a crucial object of study for understanding the development and progression of this disease. Thus, this pathway may have a role as a potential therapeutic target, as well as prognostic and diagnostic value, in patients with breast cancer. Despite the existence of selective PI3K/Akt/mTOR pathway inhibitors and current clinical trials, the cellular mechanisms are not yet known. The present review aims to understand the current state of this important disease and the paths that must be forged.

Targeted Delivery of 111In Into the Nuclei of EGFR Overexpressing Cells via Modular Nanotransporters With Anti-EGFR Affibody

Since cell nucleus is one of the most vulnerable compartments, the maximum therapeutic effect from a variety of locally acting agents, such as photosensitizers, alfa-emitters, Auger electron emitters, will be expected when they get there. Therefore, the targeted delivery of these agents into the nuclei of target tumor cells is necessary for their anticancer effects and minimization of side effects. Modular nanotransporters (MNT) are artificial polypeptides comprising several predefined modules that recognize target cell, launching their subsequent internalization, escape from endosomes, and transport the drug load to the nucleus. This technology significantly enhances the cytotoxicity of locally acting drugs in vitro and in vivo. Epidermal growth factor receptors (EGFR) are useful molecular targets as they are overexpressed in glioblastoma, head-and-neck cancer, bladder cancer, and other malignancies. Here, we examined the possibility of using internalizable anti-EGFR affibody as an EGFR-targeting MNT module for drug transport into the cancer cell nuclei. It binds to both murine and human EGFR facilitating preclinical studies. We showed that MNT with affibody on the N-terminus (MNT_N-affibody) effectively delivered the Auger electron emitter ¹¹¹In to target cell nuclei and had pronounced cytotoxic efficacy against EGFR-overexpressing human A431 epidermoid carcinoma cells. Using EGFR-expressing human adenocarcinoma MCF-7 cells, we demonstrated that in contrast to MNT with N-terminal epidermal growth factor (EGF), MNT_N-affibody and MNT with EGF on the C-terminus did not stimulate cancer cell proliferation.

Epidermal growth factor receptor ligands: targets for optimizing treatment of metastatic colorectal cancer

The discovery of epidermal growth factor (EGF) and its receptor (EGFR) revealed the connection between EGF-like ligands, signaling from the EGFR family members and cancer. Over the next fifty years, analysis of EGFR expression and mutation led to the use of monoclonal antibodies to target EGFR in the treatment of metastatic colorectal cancer (mCRC) and this treatment has improved outcomes for patients. The use of the RAS oncogene mutational status has helped to refine patient selection for EGFR antibody therapy, but an effective molecular predictor of likely responders is lacking. This review analyzes the potential utility of measuring the expression, levels and activation of EGF-like ligands and associated processes as prognostic or predictive markers for the identification of patient risk and more effective mCRC therapies.

ADAM17: An Emerging Therapeutic Target for Lung Cancer

Lung cancer is the leading cause of cancer-related mortality, which histologically is classified into small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC accounts for approximately 85% of all lung cancer diagnoses, with the majority of patients presenting with lung adenocarcinoma (LAC). KRAS mutations are a major driver of LAC, and are closely related to cigarette smoking, unlike mutations in the epidermal growth factor receptor (EGFR) which arise in never-smokers. Although the past two decades have seen fundamental progress in the treatment and diagnosis of NSCLC, NSCLC still is predominantly diagnosed at an advanced stage when therapeutic interventions are mostly palliative. A disintegrin and metalloproteinase 17 (ADAM17), also known as tumour necrosis factor-α (TNFα)-converting enzyme (TACE), is responsible for the protease-driven shedding of more than 70 membrane-tethered cytokines, growth factors and cell surface receptors. Among these, the soluble interleukin-6 receptor (sIL-6R), which drives pro-inflammatory and pro-tumourigenic IL-6 trans-signaling, along with several EGFR family ligands, are the best characterised. This large repertoire of substrates processed by ADAM17 places it as a pivotal orchestrator of a myriad of physiological and pathological processes associated with the initiation and/or progression of cancer, such as cell proliferation, survival, regeneration, differentiation and inflammation. In this review, we discuss recent research implicating ADAM17 as a key player in the development of LAC, and highlight the potential of ADAM17 inhibition as a promising therapeutic strategy to tackle this deadly malignancy.