Dual kinase inhibition of EGFR and HER2 overcomes resistance to cetuximab in a novel in vivo model of acquired cetuximab resistance

Targeted radionuclide therapy for head and neck squamous cell carcinoma: a review

Head and neck squamous cell carcinoma (HNSCC) is a type of head and neck cancer that is aggressive, difficult to treat, and often associated with poor prognosis. HNSCC is the sixth most common cancer worldwide, highlighting the need to develop novel treatments for this disease. The current standard of care for HNSCC usually involves a combination of surgical resection, radiation therapy, and chemotherapy. Chemotherapy is notorious for its detrimental side effects including nausea, fatigue, hair loss, and more. Radiation therapy can be a challenge due to the anatomy of the head and neck area and presence of normal tissues. In addition to the drawbacks of chemotherapy and radiation therapy, high morbidity and mortality rates for HNSCC highlight the urgent need for alternative treatment options. Immunotherapy has recently emerged as a possible treatment option for cancers including HNSCC, in which monoclonal antibodies are used to help the immune system fight disease. Combining monoclonal antibodies approved by the US Food and Drug Administration, such as cetuximab and pembrolizumab, with radiotherapy or platinum-based chemotherapy for patients with locally advanced, recurrent, or metastatic HNSCC is an accepted first-line therapy. Targeted radionuclide therapy can potentially be used in conjunction with the first-line therapy, or as an additional treatment option, to improve patient outcomes and quality of life. Epidermal growth factor receptor is a known molecular target for HNSCC; however, other targets such as human epidermal growth factor receptor 2, human epidermal growth factor receptor 3, programmed cell death protein 1, and programmed death-ligand 1 are emerging molecular targets for the diagnosis and treatment of HNSCC. To develop successful radiopharmaceuticals, it is imperative to first understand the molecular biology of the disease of interest. For cancer, this understanding often means detection and characterization of molecular targets, such as cell surface receptors, that can be used as sensitive targeting agents. The goal of this review article is to explore molecular targets for HNSCC and dissect previously conducted research in nuclear medicine and provide a possible path forward for the development of novel radiopharmaceuticals used in targeted radionuclide therapy for HNSCC, which has been underexplored to date.

New clinical trial design in precision medicine: discovery, development and direction

In the era of precision medicine, it has been increasingly recognized that individuals with a certain disease are complex and different from each other. Due to the underestimation of the significant heterogeneity across participants in traditional "one-size-fits-all" trials, patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket, umbrella, and platform trial designs under the master protocol framework. In recent years, the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous opportunities. Despite the rapid increase in the number of basket, umbrella, and platform trials, the current clinical and research understanding of these new trial designs, as compared with traditional trial designs, remains limited. The majority of the research focuses on methodologies, and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial designs. Therefore, we provide this comprehensive review of the discovery and development of basket, umbrella, and platform trials and their underlying logic from the perspective of precision medicine. Meanwhile, we discuss future directions on the potential development of these new clinical design in view of the "Precision Pro", "Dynamic Precision", and "Intelligent Precision". This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic, which be essential to accelerate the progression of precision medicine.

Establishment of head and neck squamous cell carcinoma mouse models for cetuximab resistance and sensitivity

Aim: Acquired resistance to the targeted agent cetuximab poses a significant challenge in finding effective anti-cancer treatments for head and neck squamous cell carcinoma (HNSCC). To accurately study novel combination treatments, suitable preclinical mouse models for cetuximab resistance are key yet currently limited. This study aimed to optimize an acquired cetuximab-resistant mouse model, with preservation of the innate immunity, ensuring intact antibody-dependent cellular cytotoxicity (ADCC) functionality. Methods: Cetuximab-sensitive and acquired-resistant HNSCC cell lines, generated in vitro, were subcutaneously engrafted in Rag2 knock-out (KO), BALB/c Nude and CB17 Scid mice with/without Matrigel or Geltrex. Once tumor growth was established, mice were intraperitoneally injected twice a week with cetuximab for a maximum of 3 weeks. In addition, immunohistochemistry was used to evaluate the tumor and its microenvironment. Results: Despite several adjustments in cell number, cell lines and the addition of Matrigel, Rag2 KO and BALB/C Nude mice proved to be unsuitable for xenografting our HNSCC cell lines. Durable tumor growth of resistant SC263-R cells could be induced in CB17 Scid mice. However, these cells had lost their resistance phenotype in vivo. Immunohistochemistry revealed a high infiltration of macrophages in cetuximab-treated SC263-R tumors. FaDu-S and FaDu-R cells successfully engrafted into CB17 Scid mice and maintained their sensitivity/resistance to cetuximab. Conclusion: We have established in vivo HNSCC mouse models with intact ADCC functionality for cetuximab resistance and sensitivity using the FaDu-R and FaDu-S cell lines, respectively. These models serve as valuable tools for investigating cetuximab resistance mechanisms and exploring novel drug combination strategies.

Expression of epidermal growth factor receptor and human epidermal growth factor receptor 2 in urothelial bladder carcinoma in an Egyptian cohort: Clinical implication and prognostic significance

BACKGROUND

Bladder cancer (BC) has a particular importance in Egyptian patients due to aggressive behavior and absence of prognostic markers.

OBJECTIVE

To evaluate the expression of gene and protein expression of HER2 and epidermal growth factor (EGFR) in Egyptian patients with BC and ultimately to investigate their clinical implication and prognostic significance.

MATERIAL AND METHODS

The study was carried out on 46 patients with urothelial bladder BC. Tissue were obtained from transurethral resection (N = 22) and radical cystectomy (N = 24) specimens. The original hematoxylin and eosin slides were re-evaluated and the formalin fixed, paraffin-embedded (FFPE) tissues which had sufficient tumor tissue (>75%) and minimal or absent tumor necrosis were selected for immunohistochemistry (IHC) and RNA extraction. Furthermore, five control biopsies were obtained from patients with cystitis. Follow-up data were retrieved from the medical records which included the treatment regimen, disease recurrence and/or progression, and survival.

RESULTS

EGFR and HER2 protein were overexpressed in 35% and 46% of patients respectively. EGFR was correlated with the tumor size, grade and pathological stage, with a similar trend for HER2. The recurrence rate was higher in patients with expression of any of the markers. Gene expression was significantly higher (10.6-folds) for EGFR and (21-folds) for HER2 in patients with BC in comparison to control patients. Survival analysis showed lower median disease-free survival in association with HER2 protein overexpression.

CONCLUSIONS

Our data highlighted the prognostic significance of EGFR and HER in BC and proposed their possible use as predictive markers and potential therapeutic targets.

Unblinding the watchmaker: cancer treatment and drug design in the face of evolutionary pressure

INTRODUCTION

Death due to cancer is mostly associated with therapy ineffectiveness, i.e. tumor cells no longer responding to treatment. The underlying dynamics that facilitate this mutational escape from selective pressure are well studied in several other fields and several interesting approaches exist to combat this phenomenon, for example in the context of antibiotic-resistance in bacteria.

AREAS COVERED

Ninety percent of all cancer-related deaths are associated with treatment failure. Here, we discuss the common treatment modalities and prior attempts to overcome acquired resistance to therapy. The underlying molecular mechanisms are discussed and the implications of emerging resistance in other systems, such as bacteria, are discussed in the context of cancer.

EXPERT OPINION

Reevaluating emerging therapy resistance in tumors as an evolutionary mechanism to survive in a rapidly and drastically altering fitness landscape leads to novel treatment strategies and distinct requirements for new drugs. Here, we propose a scheme of considerations that need to be applied prior to the discovery of novel therapeutic drugs.

Targeting Epidermal Growth Factor Receptor in Head and Neck Cancer

ABSTRACT

Head and neck squamous cell carcinomas are rising in incidence worldwide, and despite the advent of improved surgical and radiation techniques, a substantial proportion of patients have disease recurrence, where systemic therapies are the mainstay of management. Recent advances in systemic therapy include the development of epidermal growth factor receptor- and programmed death 1-targeting drugs, which have produced incremental improvements in disease outcomes. However, for most patients, responses to treatment remain elusive because of primary or acquired resistance. Novel drugs and rational drug combinations need to be tested based on biomarker identification and preclinical science that will ultimately advance outcomes for our patients. This review focuses on efforts untaken for epidermal growth factor receptor targeting in head and neck squamous cell carcinoma to date.

Nuclear HER3 expression improves the prognostic stratification of patients with HER1 positive advanced laryngeal squamous cell carcinoma

Background

Compared to the other members of human epidermal growth factor family receptors (HER), the role of HER3 has not been well defined in laryngeal cancer. The predictive and prognostic role of HER3 has been the focus of clinical attention but the research findings are contradictory, especially in laryngeal squamous cell carcinoma (LSCC). The variable localization of HER3 within cancer cells and the role of HER3 in primary and acquired resistance to HER1-targeted therapies remain unclear.

Methods

We performed a retrospective analysis of two cohorts of 66 homogeneous consecutive untreated primary advanced LSCC patients, in which co-expression of HER1, HER2 and HER3 receptors was investigated by semi-quantitative immunohistochemistry. The association of their pattern of expression with survival was evaluated by Kaplan–Meier and Cox’s proportional hazard analyses. Multivariable Cox proportional hazards models were developed to predict median 2- and 3-year RFS and 2.5- and 5-year OS. The Akaike information criterion technique and backwards stepwise procedure were used for model selections. The performance of the final Cox models was assessed with respect to calibration and discrimination.

Results

Immunohistochemical labeling for HER1 and HER2 was localized both in the cell membrane and in the cytoplasm, while HER3 labeling was observed both in the cell cytoplasm and in the nucleus. HER3 expression was inversely correlated with HER1 positivity. The expression patterns of HERs were associated with tumor differentiation. In both cohorts of patients, HER1 expression was associated with reduced relapse-free (RFS) and overall survival (OS). In HER1 positive tumors, the co-expression with nuclear HER3 was associated with better RFS and OS, compared with HER3 negative tumors or tumors expressing HER3 at cytoplasmic level. HER3 expressing tumors had a higher Geminin/MCM7 ratio than HER3 negative ones, regardless of HER1 co-expression. Multivariable analyses identified age at diagnosis, tumor site, HER1, HER3 and age at diagnosis, tumor stage, HER1, HER3, as covariates significantly associated with RFS and OS, respectively. Bootstrapping verified the good fitness of these models for predicting survivals and the optimism-corrected C-indices were 0.76 and 0.77 for RFS and OS, respectively.

Conclusions

Nuclear HER3 expression was strongly associated with favourable prognosis and allows to improve the prognostic stratification of patients with HER1 positive advanced LSCC carcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03081-0.

Effect of tyrosine kinase inhibitors on cell migration and epithelial-to-mesenchymal transition in Asian head and neck cancer cell lines

BACKGROUND

We investigated the role of epidermal growth factor (EGF) and transforming growth factor α (TGFα) on Asian head and neck cancer patient cell lines; in terms of epithelial-to-mesenchymal transition (EMT) and cell migration to determine whether these changes could be reversed using tyrosine kinase inhibitors (Gefitinib and Erlotinib).

METHODS

Cell migration, protrusion and EMT were assessed using both Scatter assay and Scratch assay. Protein expression and localisation were evaluated using immunofluorescence, SDS-PAGE and Western blotting techniques to identify the involvement of phosphorylated MAPK (Thr202/Tyr204), phosphorylated EGFR (Y1068) and phosphorylated AKT (Ser473) protein expression.

RESULTS

EGF and TGFα induced an EMT-like phenotypical change, cellular protrusion and cell migration while Gefitinib and Erlotinib blocked these morphological changes and cell migration. We also examined the effect of EGF/TGF α± tyrosine kinase inhibitors on phosphorylation sites Y1068 of epidermal growth factor receptor (EGFR). Y1068 was phosphorylated in all test conditions, and all tested concentrations of inhibitors did not inhibit Y1068 phosphorylation. EGF and TGFα increased phosphorylation of MAPK (Thr202/Tyr204) residues compared with serum-free control while a one-hour pre-treatment with tyrosine kinase inhibitor(s) before addition of growth factors completely blocked this phosphorylation. Phosphorylation of Akt Ser 473 was also induced by EGF and TGFα, and a one-hour pre-treatment with the tyrosine kinas inhibitor(s) reduced this phosphorylation.

CONCLUSION

These data suggest that Gefitinib and Erlotinib prevent activation of downstream signalling proteins MAPK (Thr202/Tyr204) and Akt (Ser473) thereby blocking phenotypic change and cell migration. This study supports the potential therapeutic value of Gefitinib and Erlotinib in targeting head and neck cancer.

An open-label, pilot study of veliparib and lapatinib in patients with metastatic, triple-negative breast cancer

BACKGROUND

Poly (ADP-ribose)-polymerase inhibitors (PARPi) have been approved for cancer patients with germline BRCA1/2 (gBRCA1/2) mutations, and efforts to expand the utility of PARPi beyond BRCA1/2 are ongoing. In preclinical models of triple-negative breast cancer (TNBC) with intact DNA repair, we have previously shown an induced synthetic lethality with combined EGFR inhibition and PARPi. Here, we report the safety and clinical activity of lapatinib and veliparib in patients with metastatic TNBC.

METHODS

A first-in-human, pilot study of lapatinib and veliparib was conducted in metastatic TNBC (NCT02158507). The primary endpoint was safety and tolerability. Secondary endpoints were objective response rates and pharmacokinetic evaluation. Gene expression analysis of pre-treatment tumor biopsies was performed. Key eligibility included TNBC patients with measurable disease and prior anthracycline-based and taxane chemotherapy. Patients with gBRCA1/2 mutations were excluded.

RESULTS

Twenty patients were enrolled, of which 17 were evaluable for response. The median number of prior therapies in the metastatic setting was 1 (range 0-2). Fifty percent of patients were Caucasian, 45% African-American, and 5% Hispanic. Of evaluable patients, 4 demonstrated a partial response and 2 had stable disease. There were no dose-limiting toxicities. Most AEs were limited to grade 1 or 2 and no drug-drug interactions noted. Exploratory gene expression analysis suggested baseline DNA repair pathway score was lower and baseline immunogenicity was higher in the responders compared to non-responders.

CONCLUSIONS

Lapatinib plus veliparib therapy has a manageable safety profile and promising antitumor activity in advanced TNBC. Further investigation of dual therapy with EGFR inhibition and PARP inhibition is needed.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02158507 . Registered on 12 September 2014.

Precision Medicine Approaches to Overcome Resistance to Therapy in Head and Neck Cancers

Head and neck squamous cell carcinoma (HNSCC) is the sixth most incident cancer worldwide. More than half of HNSCC patients experience locoregional or distant relapse to treatment despite aggressive multimodal therapeutic approaches that include surgical resection, radiation therapy, and adjuvant chemotherapy. Before the arrival of immunotherapy, systemic chemotherapy was previously employed as the standard first-line protocol with an association of cisplatin or carboplatin plus 5-fluorouracil plus cetuximab (anti-EFGR antibody). Unfortunately, acquisition of therapy resistance is common in patients with HNSCC and often results in local and distant failure. Despite our better understanding of HNSCC biology, no other molecular-targeted agent has been approved for HNSCC. In this review, we outline the mechanisms of resistance to the therapeutic strategies currently used in HNSCC, discuss combination treatment strategies to overcome them, and summarize the therapeutic regimens that are presently being evaluated in early- and late-phase clinical trials.

Patient-derived xenograft (PDX) models of colorectal carcinoma (CRC) as a platform for chemosensitivity and biomarker analysis in personalized medicine

Patient-derived xenograft (PDX) tumor models represent a valuable platform for identifying new biomarkers and novel targets, to evaluate therapy response and resistance mechanisms. This study aimed at establishment, characterization and therapy testing of colorectal carcinoma-derived PDX. We generated 49 PDX and validated identity between patient tumor and corresponding PDX. Sensitivity of PDX toward conventional and targeted drugs revealed that 92% of PDX responded toward irinotecan, 45% toward 5-FU, 65% toward bevacizumab, and 61% toward cetuximab. Expression of epidermal growth factor receptor (EGFR) ligands correlated to the sensitivity toward cetuximab. Proto-oncogene B-RAF, EGFR, Kirsten rat sarcoma virus oncogene homolog gene copy number correlated positively with cetuximab and erlotinib sensitivity. The mutational analyses revealed an individual mutational profile of PDX and mainly identical profiles of PDX from primary tumor vs corresponding metastasis. Mutation in PIK3CA was a determinant of accelerated tumor doubling time. PDX with wildtype Kirsten rat sarcoma virus oncogene homolog, proto-oncogene B-RAF, and phosphatidylinositol-4,5-bisphosphate 3-kinaseM catalytic subunit alfa showed higher sensitivity toward cetuximab and erlotinib. To study the molecular mechanism of cetuximab resistance, cetuximab resistant PDX models were generated, and changes in HER2, HER3, betacellulin, transforming growth factor alfa were observed. Global proteome and phosphoproteome profiling showed a reduction in canonical EGFR-mediated signaling via PTPN11 (SHP2) and AKT1S1 (PRAS40) and an increase in anti-apoptotic signaling as a consequence of acquired cetuximab resistance. This demonstrates that PDX models provide a multitude of possibilities to identify and validate biomarkers, signaling pathways and resistance mechanisms for clinically relevant improvement in cancer therapy.

Cytoplasmic Chaperones Enhance Soluble Expression of Anti-EGFR huscFv in Escherichia coli

Background:

Overexpression of EGFR is associated with carcinogenesis in more than 70% of head and neck cancers. Anti-EGFR monoclonal antibodies bind to the extracellular domain of EGFR and block the EGFR downstream signaling pathway, which results in the suppression of the growth of the tumor cells. Escherichia coli is the preferred system for expressing various recombinant proteins, including single chain antibodies, but the formation of inclusion bodies negatively affects the efficacy of this system. Several strategies have been suggested to solve this problem, notably the utilization of molecular chaperones.

Objectives:

In this study, we attempted to increase the soluble expression of huscfv antibody via co-expression with the cytoplasmic chaperones.

Materials and Methods:

To achieve this purpose, chaperones plasmids pG-KJE8, pGro7, pKjE7, pTf16 and pG-Tf2 encoding cytoplasmic chaperones were co-expressed with the humanized anti-EGFR scFv construct in E. coli. Different temperatures, incubations times, and concentrations of IPTG were used to produce an active antibody with the highest solubility. Results were analyzed by SDS-PAGE. Soluble huscFv was purified by Ni-NTA column and the biologic activity of the recombinant protein was determined by ELISA.

Result:

The results indicated that the highest concentrations of humanized anti-EGFR scFv were obtained by co-expression of huscFv via chaperone plasmid pG-KJE8 with 0.2 mM concentration of inducer (IPTG), culture temperature of 25 °C, and 4 h incubation time after induction.

Conclusion:

In conclusion, co-expression with chaperones could be used as an efficient strategy to produce soluble active ScFvs in E. coli.

Combined targeting EGFR and SRC as a potential novel therapeutic approach for the treatment of triple negative breast cancer

Background:

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited therapeutic options. Epidermal growth factor receptor (EGFR) has been shown to be over-expressed in TNBC and represents a rational treatment target.

Methods:

We examined single agent and combination effects for afatinib and dasatinib in TNBC. We then determined IC₅₀ and combination index values using Calcusyn. Functional analysis of single and combination treatments was performed using reverse phase protein array and cell cycle analysis. Finally, we determined the anticancer effects of the combination in vivo.

Results:

A total of 14 TNBC cell lines responded to afatinib with IC₅₀ values ranging from 0.008 to 5.0 µM. Three cell lines, belonging to the basal-like subtype of TNBC, were sensitive to afatinib. The addition of afatinib enhanced response to the five other targeted therapies in HCC1937 and HDQP1 cells. The combination of afatinib with dasatinib caused the greatest growth inhibition in both cell lines. The afatinib/dasatinib combination was synergistic and/or additive in 13/14 TNBC cell lines. Combined afatinib/dasatinib treatment induced G1 cell cycle arrest. Reverse phase protein array results showed the afatinib/dasatinib combination resulted in efficient inhibition of both pERK(T202/T204) and pAkt(S473) signalling in BT20 cells, which was associated with the greatest antiproliferative effects. High baseline levels of pSrc(Y416) and pMAPK(p38) correlated with sensitivity to afatinib, whereas low levels of B-cell lymphoma 2 (Bcl2) and mammalian target of rapamycin (mTOR) correlated with synergistic growth inhibition by combined afatinib and dasatinib treatment. In vivo, the combination treatment inhibited tumour growth in a HCC1806 xenograft model.

Conclusions:

We demonstrate that afatinib combined with dasatinib has potential clinical activity in TNBC but warrants further preclinical investigation.

Preferential Response of Basal-Like Head and Neck Squamous Cell Carcinoma Cell Lines to EGFR-Targeted Therapy Depending on EREG-Driven Oncogenic Addiction

The management of locally advanced head and neck squamous cell carcinoma (HNSCC) with Cetuximab, a monoclonal antibody targeting the epidermal growth factor receptor (EGFR), achieves only moderate response rates, and clinical trials that evaluated EGFR-blockade with tyrosine kinase inhibitors (TKI) yielded disappointing results. Inter-tumor heterogeneity may hinder the therapeutic efficiency of anti-EGFR treatments. HNSCC heterogeneity was addressed in several studies, which all converged towards the definition of molecular subgroups. They include the basal subgroup, defined by the deregulated expression of factors involved in the EGFR signaling pathway, including the epiregulin EGFR ligand encoded by the EREG gene. These observations indicate that basal tumors could be more sensitive to anti-EGFR treatments. To test this hypothesis, we performed a screen of a representative collection of basal versus non-basal HNSCC cell lines for their sensitivity to several anti-EGFR drugs (Cetuximab, Afatinib, and Gefitinib), tested as monotherapy or in combination with drugs that target closely-linked pathways [Mitogen-activated protein kinase kinase/extracellular signal–regulated kinases (MEK), mammalian Target of Rapamycine (mTOR) or Human Epidermal growth factor Receptor 2 (HER2)]. Basal-like cell lines were found to be more sensitive to EGFR blockade alone or in combination with treatments that target MEK, mTOR, or HER2. Strikingly, the basal-like status was found to be a better predictor of cell response to EGFR blockade than clinically relevant mutations [e.g., cyclin-dependent kinase Inhibitor 2A (CDKN2A)]. Interestingly, we show that EGFR blockade inhibits EREG expression, and that EREG knock-down decreases basal cell clonogenic survival, suggesting that EREG expression could be a predictive functional marker of sensitivity to EGFR blockade in basal-like HNSCC.

Simultaneous targeting of EGFR, HER2, and HER4 by afatinib overcomes intrinsic and acquired cetuximab resistance in head and neck squamous cell carcinoma cell lines

The epidermal growth factor receptor (EGFR, HER1) is a therapeutic target in head and neck squamous cell carcinoma (HNSCC). After initial promising results with EGFR-targeted therapies such as cetuximab, therapeutic resistance has become a major clinical problem, and new treatment options are therefore necessary. Moreover, the relationship between HER receptors, anti-EGFR therapies, and the human papillomavirus (HPV) status in HNSCC is not fully understood. In contrast to first-generation EGFR inhibitors, afatinib irreversibly inhibits multiple HER receptors simultaneously. Therefore, treatment with afatinib might result in a more pronounced therapeutic benefit, even in patients experiencing cetuximab resistance. In this study, the cytotoxic effect of afatinib as single agent and in combination with cisplatin was investigated in cetuximab-sensitive, intrinsically cetuximab-resistant, and acquired cetuximab-resistant HNSCC cell lines with different HPV status under normoxia and hypoxia. Furthermore, the influence of cetuximab resistance, HPV, and hypoxia on the expression of HER receptors was investigated. Our results demonstrated that afatinib was able to establish cytotoxicity in cetuximab-sensitive, intrinsically cetuximab-resistant, and acquired cetuximab-resistant HNSCC cell lines, independent of the HPV status. However, cross-resistance between cetuximab and afatinib might be possible. Treatment with afatinib caused a G₀ /G₁ cell cycle arrest as well as induction of apoptotic cell death. Additive to antagonistic interactions between afatinib and cisplatin could be observed. Neither cetuximab resistance nor HPV status significantly influenced the expression of HER receptors in HNSCC cell lines. In contrast, the expression of EGFR, HER2, and HER3 was significantly altered under hypoxia. Oxygen deficiency is a common characteristic of HNSCC tumors, and these hypoxic tumor regions often contain cells that are more resistant to treatment. However, we observed that afatinib maintained its cytotoxic effect under hypoxia. In conclusion, our preclinical data support the hypothesis that afatinib might be a promising therapeutic strategy to treat patients with HNSCC experiencing intrinsic or acquired cetuximab resistance.

Afatinib

Afatinib (BIBW 2992, US: Gilotrif^TM, other countries: Giotrif©) is an irreversible blocker of the ErbB family, acting at the tyrosine kinases of these proteins. In 2013, it was approved by the FDA and the EMA for the treatment of adults with advanced, EGFR mutation-positive non-small-cell lung cancer. Further investigations for the treatment of many other tumors with afatinib, e.g., HNSCC and breast cancer, are ongoing.

Continued use of afatinib with the addition of cetuximab after progression on afatinib in patients with EGFR mutation-positive non-small-cell lung cancer and acquired resistance to gefitinib or erlotinib

OBJECTIVES

In a phase Ib trial, afatinib plus cetuximab demonstrated promising clinical activity (objective response rate [ORR]: 29%; median progression-free survival [PFS]: 4.7 months) in patients with epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) with acquired resistance to erlotinib or gefitinib. Here, a separate cohort exploring afatinib plus cetuximab after progression on afatinib is reported.

MATERIALS AND METHODS

Patients with EGFR mutation-positive NSCLC who progressed on erlotinib or gefitinib received afatinib 40mg daily until progression, followed by afatinib daily plus cetuximab 500mg/m² every 2 weeks until progression or intolerable adverse events (AEs). Endpoints included safety, ORR, and PFS.

RESULTS

Thirty-seven patients received afatinib monotherapy. Two (5%) patients responded; median PFS was 2.7 months. Thirty-six patients transitioned to afatinib plus cetuximab. Four (11%) patients responded; median PFS was 2.9 months. Median PFS with afatinib plus cetuximab for patients who received afatinib monotherapy for ≥12 versus <12 weeks was 4.9 versus 1.8 months (p=0.0354), and for patients with T790M-positive versus T790M-negative tumors was 4.8 versus 1.8 months (p=0.1306). Fifty percent of patients receiving afatinib plus cetuximab experienced drug-related grade 3/4 AEs. The most frequent drug-related AEs (any grade) were diarrhea (70%), rash (49%), and fatigue (35%) with afatinib monotherapy and rash (69%), paronychia (39%), and dry skin (36%) with afatinib plus cetuximab.

CONCLUSION

Sequential EGFR blockade with afatinib followed by afatinib plus cetuximab had a predictable safety profile and demonstrated modest activity in patients with EGFR mutation-positive NSCLC with resistance to erlotinib or gefitinib. CLINICALTRIALS.

GOV IDENTIFIER

NCT01090011.

STAT3 signaling mediates tumour resistance to EGFR targeted therapeutics

Several EGFR inhibitors are currently undergoing clinical assessment or are approved for the clinical management of patients with varying tumour types. However, treatment often results in a lack of response in many patients. The majority of patients that initially respond eventually present with tumours that display acquired resistance to the original therapy. A large number of receptor tyrosine and intracellular kinases have been implicated in driving signaling that mediates this tumour resistance to anti-EGFR targeted therapy, and in a few cases these discoveries have led to overall changes in prospective tumour screening and clinical practice (K-RAS in mCRC and EGFR T790M in NSCLC). In this mini-review, we specifically focus on the role of the STAT3 signaling axis in providing both intrinsic and acquired resistance to inhibitors of the EGFR. We also focus on STAT3 pathway targeting in an attempt to overcome resistance to anti-EGFR therapeutics.

Enhanced tumor-targeting selectivity by modulating bispecific antibody binding affinity and format valence

Bispecific antibodies are considered attractive bio-therapeutic agents owing to their ability to target two distinct disease mediators. Cross-arm avidity targeting of antigen double-positive cancer cells over single-positive normal tissue is believed to enhance the therapeutic efficacy, restrict major escape mechanisms and increase tumor-targeting selectivity, leading to reduced systemic toxicity and improved therapeutic index. However, the interplay of factors regulating target selectivity is not well understood and often overlooked when developing clinically relevant bispecific therapeutics. We show in vivo that dual targeting alone is not sufficient to endow selective tumor-targeting, and report the pivotal roles played by the affinity of the individual arms, overall avidity and format valence. Specifically, a series of monovalent and bivalent bispecific IgGs composed of the anti-HER2 trastuzumab moiety paired with affinity-modulated V_H and V_L regions of the anti-EGFR GA201 mAb were tested for selective targeting and eradication of double-positive human NCI-H358 non-small cell lung cancer target tumors over single-positive, non-target NCI-H358-HER2 CRISPR knock out tumors in nude mice bearing dual-flank tumor xenografts. Affinity-reduced monovalent bispecific variants, but not their bivalent bispecific counterparts, mediated a greater degree of tumor targeting selectivity, while the overall efficacy against the targeted tumor was not substantially affected.

Preclinical studies of a Pro-antibody-drug conjugate designed to selectively target EGFR-overexpressing tumors with improved therapeutic efficacy

Antibody-drug conjugates (ADCs) have exhibited potent clinical benefits in cancer therapy. However, development of ADCs against epidermal growth factor receptor (EGFR) has limitations because of wide expression of EGFR in both normal and tumor tissues. Previously, we developed an anti-EGFR protease-activated antibody (pro-antibody), termed as PanP, which remains inert against EGFR until activated by tumor-specific protease. Herein, we for the first time report a new class of pro-antibody-drug conjugate (PDC) against EGFR, denoted as PanP-DM1. It has been designed to selectively target the EGFR-overexpressing tumor cells and exert greater anti-tumor activity compared with PanP. Our data showed that PanP-DM1 also could be selectively activated by tumor-specific protease 'uPA'. Furthermore, activated PanP-DM1 was potently cytotoxic against EGFR-overexpressing tumor cell lines in vitro. Crucially, our data indicated that PanP-DM1 was significantly more effective in eradicating EGFR-overexpressing tumors in vivo. Additionally, toxicity was preliminarily evaluated in mice as measured by body weight loss. In summary, our study suggests that PanP-DM1, a novel pro-antibody-drug conjugate, has cancer-selectivity, efficacy and safety profile that supports its potential use for EGFR-overexpressing tumors.

Lapatinib-capecitabine versus capecitabine alone as radiosensitizers in RAS wild-type resectable rectal cancer, an adaptive randomized phase II trial (LaRRC trial): study protocol for a randomized controlled trial

BACKGROUND

Preoperative radiochemotherapy followed by surgical removal of the rectum with total mesorectum excision is the preferred treatment option for stages II and III rectal cancer. However, development of metastatic disease is the main cause of death for these patients with 5-year disease-free survival rates of 56 %. Anti-epidermal growth factor receptor (EGFR) targeted therapy is effective in metastatic rectal cancer, and human epidermal growth factor receptor 2 (HER-2) signaling may mediate resistance to EGFR inhibitors. Moreover, preclinical data support a synergistic effect of EGFR inhibition with radiation therapy.

METHODS/DESIGN

This Bayesian phase II trial with adaptive randomization was designed to assess the efficacy of adding lapatinib, a dual inhibitor of EGFR and HER-2, to standard radiochemotherapy with capecitabine in stages II and III rectal cancer.

DISCUSSION

The results of this trial will provide evidence of the feasibility and efficacy of the combination of lapatinib-capecitabine as radiosensitizers and explore potential predictive biomarkers for response to this novel neoadjuvant approach to resectable rectal cancer.

TRIAL REGISTRATION

EudraCT 2013-001203-36 . Registered on 13 December 2013.

Effects of neratinib and combination with irradiation and chemotherapy in head and neck cancer cells

OBJECTIVE

Prognosis of patients with head and neck squamous cell carcinoma (HNSCC) is still poor. Novel therapeutic approaches are of great interest to improve the effects of radiochemotherapy. We evaluated the effects of tyrosine kinase inhibitor neratinib on HNSCC cell lines CAL27, SCC25 and FaDu as a single agent and in combination with irradiation and chemotherapy.

METHODS

Effects of neratinib were evaluated in HNSCC cell lines CAL27, SCC25 and FaDu. Effect on cell viability of neratinib and combination with cisplatin and irradiation was measured using CCK-8 assays and clonogenic assays. Western blot analysis was performed to distinguish the effect on epithelial growth factor receptor and HER2 expression. Apoptosis was evaluated by flow cytometry analysis.

RESULTS

Growth inhibition was achieved in all cell lines, whereas combination of cisplatin and neratinib showed greater inhibition than each agent alone. Apoptosis was induced in all cell lines. Combination of neratinib with irradiation or cisplatin showed significantly increased apoptosis. In clonogenic assays, significant growth inhibition was observed in all investigated cell lines.

CONCLUSION

Neratinib, as a single agent or in combination with chemo-irradiation, may be a promising treatment option for patients with head and neck cancer.

Pan-HER-An antibody mixture targeting EGFR, HER2 and HER3 abrogates preformed and ligand-induced EGFR homo- and heterodimers

The human epidermal growth factor receptor (HER)-family is involved in development of many epithelial cancers. Therefore, HER-family members constitute important targets for anti-cancer therapeutics such as monoclonal antibodies (mAbs). A limitation to the success of single HER-targeting mAbs is development of acquired resistance through mechanisms such as alterted receptor dimerization patterns and dependencies. Pan-HER is a mixture of six mAbs simultaneously targeting epidermal growth factor receptor (EGFR), HER2 and HER3 with two mAbs against each receptor. Pan-HER has previously demonstrated broader efficacy than targeting single or dual receptor combinations also in resistant settings. In light of this broad efficacy, we decided to investigate the effect of Pan-HER compared with single HER-targeting with single and dual mAbs on HER-family cross-talk and dimerization focusing on EGFR. The effect of Pan-HER on cell proliferation and HER-family receptor degradation was superior to treatment with single mAbs targeting either single receptor, and similar to targeting a single receptor with two non-overlapping antibodies. Furthermore, changes in EGFR-dimerization patterns after treatment with Pan-HER were investigated by in situ proximity ligation assay and co-immunoprecipitation, demonstrating that Pan-HER and the EGFR-targeting mAb mixture efficiently down-regulate basal EGFR homo- and heterodimerization in two tested cell lines, whereas single mAbs had limited effects. Pan-HER and the EGFR-targeting mAb mixture also blocked EGF-binding and thereby ligand-induced changes in EGFR-dimerization levels. These results suggest that Pan-HER reduces the cellular capability to switch HER-dependency and dimerization pattern in response to treatment and thus hold promise for future clinical development of Pan-HER in resistant settings.

Genomic insights into head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and is frequently impervious to curative treatment efforts. Similar to other cancers associated with prolonged exposure to carcinogens, HNSCCs often have a high burden of mutations, contributing to substantial inter- and intra-tumor heterogeneity. The heterogeneity of this malignancy is further increased by the rising rate of human papillomavirus (HPV)-associated (HPV+) HNSCC, which defines an etiological subtype significantly different from the more common tobacco and alcohol associated HPV-negative (HPV-) HNSCC. Since 2011, application of large scale genome sequencing projects by The Cancer Genome Atlas (TCGA) network and other groups have established extensive datasets to characterize HPV- and HPV+ HNSCC, providing a foundation for advanced molecular diagnoses, identification of potential biomarkers, and therapeutic insights. Some genomic lesions are now appreciated as widely dispersed. For example, HPV- HNSCC characteristically inactivates the cell cycle suppressors TP53 (p53) and CDKN2A (p16), and often amplifies CCND1 (cyclin D), which phosphorylates RB1 to promote cell cycle progression from G1 to S. By contrast, HPV+ HNSCC expresses viral oncogenes E6 and E7, which inhibit TP53 and RB1, and activates the cell cycle regulator E2F1. Frequent activating mutations in PIK3CA and inactivating mutations in NOTCH1 are seen in both subtypes of HNSCC, emphasizing the importance of these pathways. Studies of large patient cohorts have also begun to identify less common genetic alterations, predominantly found in HPV- tumors, which suggest new mechanisms relevant to disease pathogenesis. Targets of these alterations including AJUBA and FAT1, both involved in the regulation of NOTCH/CTNNB1 signaling. Genes involved in oxidative stress, particularly CUL3, KEAP1 and NFE2L2, strongly associated with smoking, have also been identified, and are less well understood mechanistically. Application of sophisticated data-mining approaches, integrating genomic information with profiles of tumor methylation and gene expression, have helped to further yield insights, and in some cases suggest additional approaches to stratify patients for clinical treatment. We here discuss some recent insights built on TCGA and other genomic foundations.

Afatinib in squamous cell carcinoma of the head and neck

INTRODUCTION

Recently new data on the efficacy of afatinib in head and neck squamous cell carcinoma (HNSCC) have been published.

AREAS COVERED

We searched the literature for published and ongoing studies with afatinib in HNSCC. Phase I data and results of phase II and III studies of afatinib in HNSCC are discussed. The maximum tolerated dose (MTD) of afatinib monotherapy with continuous administration was determined at 40 or 50 mg/day, rash and diarrhea being the principal dose-limiting toxicities. The MTD was lower when combined with chemotherapy. Studies with afatinib have been conducted or are ongoing both in the recurrent or metastatic (R/M) and in the locoregionally advanced (LA) HNSCC disease setting.

EXPERT OPINION

Comparable disease control and tumor shrinkage rates were observed with cetuximab and afatinib in HNSCC progressing after platinum-containing chemotherapy. In patients with R/M- Squamous cell carcinoma of the head and neck (SCCHN) who had progressed on/after first-line platinum-based therapy, afatinib induced significantly higher disease control rate, longer progression-free survival and improved patient-reported outcome compared to methotrexate. Randomized phase III trials studying the role of adjuvant afatinib after definitive or postoperative chemoradiation in LA-HNSCC are ongoing.

Multiplexed Analysis for Anti-Epidermal Growth Factor Receptor Tumor Cell Growth Inhibition Based on Quantum Dot Probes

Quantum dot (QD) multicolor analysis was achieved by labeling the epidermal growth factor and labeling the antibody against the epidermal growth factor receptor (anti-EGFR) using different QDs. On the basis of the fluorescence intensity of the two types of QDs, the amount of epidermal growth factors (EGFs) in the cells and anti-EGFRs bound to EGFRs were analyzed. The functions of anti-EGFR in preventing HeLa cells from engulfing EGF and inhibiting overproliferation of the HeLa cells were also studied. Meanwhile, parallel analysis was conducted to analyze the heterogeneity of cells at the single-cell level using a single-cell array. This provides a novel approach for the multiplexed analysis for the anti-EGFR functions in cells together with the cell heterogeneity. It also lays a foundation for parallel analysis and detection, using various fluorescence probes, simultaneous tracking, and detection of multiple targets at an overall level or individual level, and multichannel analysis of drug effects.

Inhibition of proliferation and induction of apoptosis in RB116 retinoblastoma cells by afatinib treatment

The present study investigates the effect of afatinib on the growth, induction of apoptosis in RB116 cells, and reduction of carcinoma growth in the mice transplanted with RB116 cells. The results from MTT assay revealed that afatinib inhibited the growth of RB116 cells in a dose-dependent manner. Proliferation of RB116 cells was reduced to 64 % on treatment with 200 μM concentration of afatinib after 48 h. Afatinib treatment of RB116 cells at 200 μM concentration induced apoptosis and necrosis in 49.7 and 9.4 %, respectively, after 48 h. In the RB116-transplanted mice, treatment with afatinib at 10-mg/kg doses for 45 days caused a significant (p < 0.005) reduction in the tumor volume compared to the control group. The tissue lysates of the mice containing RB116 transplant showed a significant decrease in the expressions of Ki67 and p53 in the afatinib treatment group after 45 days. However, the expression of caspase-3 was increased and of Bcl-2 remained unaltered on treatment with afatinib. Measurement of the body weight of afatinib-treated animals showed no reduction during the study. Thus, afatinib can be of therapeutic value for the treatment of retinoblastoma.

Improving target cell specificity using a novel monovalent bispecific IgG design

Monovalent bispecific IgGs cater to a distinct set of mechanisms of action but are difficult to engineer and manufacture because of complexities associated with correct heavy and light chain pairing. We have created a novel design, “DuetMab,” for efficient production of these molecules. The platform uses knobs-into-holes (KIH) technology for heterodimerization of 2 distinct heavy chains and increases the efficiency of cognate heavy and light chain pairing by replacing the native disulfide bond in one of the C_H1-C_L interfaces with an engineered disulfide bond. Using two pairs of antibodies, cetuximab (anti-EGFR) and trastuzumab (anti-HER2), and anti-CD40 and anti-CD70 antibodies, we demonstrate that DuetMab antibodies can be produced in a highly purified and active form, and show for the first time that monovalent bispecific IgGs can concurrently bind both antigens on the same cell. This last property compensates for the loss of avidity brought about by monovalency and improves selectivity toward the target cell.

Preclinical evaluation of afatinib (BIBW2992) in esophageal squamous cell carcinoma (ESCC)

Esophageal squamous cell carcinoma (ESCC) is the eighth most common cancer worldwide. Epidermal growth factor receptors (EGFR) are often overexpressed in esophageal cancers, thus anti-EGFR inhibitors have been evaluated in ESCC. Afatinib was an irreversible inhibitor of these ErbB family receptors. This study characterized the preclinical activity of afatinib in five ESCC cell lines: HKESC-1, HKESC-2, KYSE510, SLMT-1 and EC-1. ESCC cell lines were sensitive to afatinib with IC50 concentrations at lower micro-molar range (at 72 hour incubation: HKESC-1 = 0.002 μM, HKESC-2 = 0.002 μM, KYSE510 = 1.090 μM, SLMT-1 = 1.161 μM and EC-1 = 0.109 μM) with a maximum growth inhibition over 95%. Afatinib can strongly induce G0/G1 cell cycle arrest in HKESC-2 and EC-1 in a dose- and time-dependent manner. The phosphorylation of ErbB family downstream effectors such as pAKT, pS6 and pMAPK were significantly inhibited in HKESC-2 and EC-1. Apoptosis was observed in both cell lines at 24 hours after exposure to afatinib, as determined by the presence of cleaved PARP. Afatinib could effectively inhibit HKESC-2 tumor growth in mice without obvious toxicity. Afatinib alone has shown excellent growth inhibitory effect on ESCC in both in vitro and in vivo models, however, no synergistic effect was observed when it was combined with chemotherapeutic agents such as 5-fluorouracil (5-FU) and cisplatin. In summary, afatinib can inhibit cell proliferation effectively by arresting the cells in G0/G1 phase, as well as inducing apoptosis in ESCC. These findings warrant further studies of afatinib as therapeutic agent in treating ESCC.

Increased Expression of HER2, HER3, and HER2:HER3 Heterodimers in HPV-Positive HNSCC Using a Novel Proximity-Based Assay: Implications for Targeted Therapies

PURPOSE

In other cancer types, HPV infection has been reported to coincide with overexpression of HER2 (ERBB2) and HER3 (ERBB3); however, the association between HER2 or HER3 expression and dimer formation in HNSCC has not been reported. Overexpression of HER2 and HER3 may contribute to resistance to EGFR inhibitors, including cetuximab, although the contribution of HPV in modulating cetuximab response remains unknown. Determination of heterodimerization of HER receptors is challenging and has not been reported in HNSCC. The present study aimed to determine the expression of HER proteins in HPV(+) versus HPV(-) HNSCC tumors using a proximity-based protein expression assay (VeraTag), and to determine the efficacy of HER-targeting agents in HPV(+) and HPV(-) HNSCC cell lines.

EXPERIMENTAL DESIGN

Expression of total HER1, HER2, and HER3, p95HER2, p-HER3, HER1:HER1 homodimers, HER2:HER3 heterodimers, and the HER3-PI3K complex in 88 HNSCC was determined using VeraTag, including 33 baseline tumors from individuals treated in a trial including cetuximab. Inhibition of cell growth and protein activation with cetuximab and afatinib was compared in HPV(+) and HPV(-) cetuximab-resistant cell lines.

RESULTS

Expression of total HER2, total HER3, HER2:HER3 heterodimers, and the HER3:PI3K complex were significantly elevated in HPV(+) HNSCC. Total EGFR was significantly increased in HPV(-) HNSCC where VeraTag assay results correlated with IHC. Afatinib significantly inhibited cell growth when compared with cetuximab in the HPV(+) and HPV(-) cetuximab-resistant HNSCC cell lines.

CONCLUSIONS

These findings suggest that agents targeting multiple HER proteins may be effective in the setting of HPV(+) HNSCC and/or cetuximab resistance.

Melanoma-associated antigen expression and the efficacy of tyrosine kinase inhibitors in head and neck cancer

Melanoma-associated antigen (MAGE) has been identified in a variety of types of cancer. The expression of several MAGE subgroups is correlated with poor prognosis and chemotherapeutic resistance. One target of chemotherapeutic treatment in head and neck cancer is the epidermal growth factor receptor (EGFR). The efficacy of tyrosine kinase inhibitors (TKI) in the context of melanoma-associated antigens is discussed in the present study. Five human squamous cell carcinoma cell lines were treated with the EGFR TKIs, erlotinib and gefitinib. The efficacy of these agents was measured using a crystal violet assay. Furthermore, the expression levels of MAGE-A1, -A5, -A8, -A9, -A11 and -A12 were determined by reverse transcription-quantitative polymerase chain reaction. The association between TKI efficacy and MAGE-A expression was analyzed by linear regression. The cell lines revealed inhomogeneous expression patterns for the MAGE-A subgroups. Four of the five cell lines demonstrated a good response to erlotinib and gefitinib. However, treatment with erlotinib induced better results than those of gefitinib, and revealed a concentration-dependent effect. The expression of MAGE-A5 and -A11 were significantly correlated with lower efficacy of erlotinib and gefitinib. By contrast, MAGE-A12 was associated with a superior response to these two drugs. One cell line, which expressed all investigated MAGE-A subgroups, was entirely resistant to the two TKIs. These results revealed a notable correlation between MAGE-A5 and -A11 and lower efficacy of EGFR TKIs. Pretreatment analysis of MAGE-A status may therefore aid improvement of chemoprevention using erlotinib and gefitinib in head and neck cancer.

Structure-based development and optimization of therapy antibody drugs against TNFα

Previously, we reported on the crystal structures of the Fab fragments of two food and drug administration approved therapeutic antibodies, Infliximab and Adalimumab, in complex with TNFα. The structurally identified epitopes on TNFα reveal the mechanism of TNFα inhibition by partially overlapping with the TNFα-receptor interface. In this study, we launched a screen of a phage display library to isolate novel anti-TNFα antibodies based on the adalimumab epitope. Structural analysis, the phage display antibody isolation technology, step-by-step antibody optimization, complementarity-determining region residues random mutagenesis, phage ELISA, binding affinity characterization, and cell signaling assays were used for the development and optimization of the novel anti-TNFα antibodies. Moreover, one of the novel antibodies, hAta09, has a superior inhibitory effect on TNFα function and signaling. Taken together, our report established that the novel anti-TNFα antibody hAta09 may achieve clinical efficacy in a TNFα-associated disease.

Afatinib inhibits proliferation and invasion and promotes apoptosis of the T24 bladder cancer cell line

Afatinib is a highly selective, irreversible inhibitor of the epidermal growth factor receptor (EGFR) and human EGFR 2 (HER-2). Although preclinical and clinical studies have indicated that afatinib has antitumor activity and clinical efficacy in non-small cell lung carcinoma, head and neck squamous cell carcinoma and breast cancer, there are few studies investigating its inhibitory effect on human bladder carcinoma cells. In this study, the antitumor effect of afatinib was investigated on the T24 bladder cancer cell line. The T24 bladder cancer cell line was treated with afatinib at various concentrations (0, 1, 5, 10 and 20 µmol/l). MTT assay was used to estimate the proliferation of the T24 cells; flow cytometric analysis was used to estimate the effect of afatinib on T24 cell apoptosis; cell invasion ability was assessed by a Transwell invasion assay; and western blot analysis was used to detect the expression of Bcl-2, Bax, Akt, extracellular-signal-regulated kinase (ERK)1/2, matrix metalloproteinase (MMP)-2 and MMP-9. The MTT assay demonstrated that afatinib inhibited the proliferation of T24 cells in a dose- and time-dependent manner. Flow cytometric analysis revealed that the cell apoptosis rate increased as the concentration of afatinib increased. The cell invasion assay indicated that afatinib treatment significantly inhibited the invasive behavior of T24 cells in a dose-dependent manner. Western blot analysis showed that with increasing afatinib concentrations, Bcl-2, phosphorylated (p)-ERK1/2, p-Akt, MMP-2 and MMP-9 expression levels were significantly decreased, whereas total (t)-ERK1/2 and t-Akt expression levels remained basically unchanged, and Bax expression levels were greatly increased. The results indicate that afatinib inhibits the proliferation and invasion of T24 cells in vitro and induces the apoptosis of these cells by inhibiting the EGFR signaling network.

Synergistic Blockade of EGFR and HER2 by New-Generation EGFR Tyrosine Kinase Inhibitor Enhances Radiation Effect in Bladder Cancer Cells

Blockade of EGFR has been proved useful in enhancing the effect of radiotherapy, but the advantages of new-generation EGFR tyrosine kinase inhibitors (TKI) in radiosensitization are not well known. We used two human bladder cancer cells with wild-type EGFR to study the synergism between irradiation and afatinib (an EGFR/HER2 dual kinase inhibitor) or erlotinib (an EGFR kinase inhibitor). Here, we showed that afatinib has better radiosensitizing effect than erlotinib in increasing cancer cell killing, the percentage of apoptotic cells, and DNA damage. Afatinib is also superior to erlotinib in combining radiation to decrease tumor size, inhibit glucose metabolism, and enhance apoptotic proteins in vivo. Finally, erlotinib suppressed cell growth and induced more DNA damage in bladder cancer cells transfected with HER2 shRNA, but not in control vector-treated cells. In conclusion, concomitant blockade of radiation-activated EGFR and HER2 signaling by a new-generation EGFR TKI better inhibits the growth of bladder cancer cells both in vitro and in vivo. The absence of radiosensitization by EGFR inhibition alone and the greater radiosensitizing effect of EGFR inhibitor in HER2 knocked down cells suggest the synergism between HER2 and EGFR in determining radiosensitivity. The regained radiosensitizing activity of erlotinib implies that with proper HER2 inhibition, EGFR tyrosine kinase is still a potential target to enhance radiotherapy effect in these seemingly unresponsive bladder cancer cells.

HER2 as a therapeutic target in head and neck squamous cell carcinoma

The majority of patients with head and neck squamous cell carcinoma (HNSCC) present with advanced-stage disease. The current standard of care is surgery followed by adjuvant radiotherapy with or without chemotherapy or chemoradiation alone. The addition of cetuximab for the treatment of patients with locally advanced or recurrent/metastatic HNSCC has improved overall survival and locoregional control; however, responses are often modest, and treatment resistance is common. A variety of therapeutic strategies are being explored to overcome cetuximab resistance by blocking candidate proteins implicated in resistance mechanisms such as HER2. Several HER2 inhibitors are in clinical development for HNSCC, and HER2-targeted therapy has been approved for several cancers. This review focuses on the biology of HER2, its role in cancer development, and the rationale for clinical investigation of HER2 targeting in HNSCC.

Overcoming acquired resistance to cetuximab by dual targeting HER family receptors with antibody-based therapy

Background

Cetuximab, an anti-EGFR monoclonal antibody, is used to treat several cancers. However, many patients who initially respond to cetuximab acquire resistance. To examine mechanisms of acquired resistance, we developed a series of cetuximab-resistant (Ctx^R) clones derived from the cetuximab sensitive (Ctx^S) non-small cell lung cancer (NSCLC) cell line H226. Previous studies characterizing this model revealed that: 1) EGFR was robustly overexpressed in Ctx^R clones due to decreased EGFR ubiquitination and degradation and 2) Ctx^R clones expressed increased HER2 and HER3 activation resulting in constitutive activation of the PI3K/AKT signaling axis. These findings suggest that dual targeting HER family receptors would be highly beneficial in the Ctx^R setting.

Results

Since HER3 has been implicated in resistance to EGFR inhibitors, the efficacy of dually targeting both EGFR and HER3 in Ctx^R models was evaluated. First, EGFR and HER3 expression were knocked down with siRNAs. Compared to the Ctx^S parental cell line (HP), all Ctx^R clones exhibited robust decreases in cell proliferation upon dual knockdown. Analysis of Ctx^R clones indicated that neuregulin-1 was highly overexpressed compared to HP cells. Incubation of HP cells with neuregulin-1 rendered them resistant to cetuximab. Next, dual treatment of Ctx^R clones with cetuximab and the HER3 neutralizing monoclonal antibody (mAb) U3-1287 led to potent anti-proliferative effects. Blockade of EGFR with cetuximab resulted in inactivation of MAPK, while blockade of HER3 with U3-1287 resulted in the inactivation of AKT. Treatment with both mAbs resulted in knockdown of both signaling pathways simultaneously. HER2 was also strongly inactivated upon dual mAb therapy, suggesting that this treatment regimen can diminish signaling from three HER family receptors. De novo Ctx^R H226 mouse xenografts were established to determine if dual therapy could overcome acquired resistance to cetuximab in vivo. Tumors that had acquired resistance to cetuximab were significantly growth delayed upon dual treatment of U3-1287 and cetuximab compared to those continued on cetuximab only. Combinatorial-treated xenograft tumors expressed decreased Ki67 and increased cleaved caspase-3 levels compared to tumors treated with either monotherapy.

Conclusions

These studies demonstrate that dually targeting HER family receptors with antibody-based therapies can overcome acquired resistance to cetuximab.

miR-135b contributes to the radioresistance by targeting GSK3β in human glioblastoma multiforme cells

Radioresistance remains a major challenge in the treatment of glioblastoma multiforme (GBM). Recent data strongly suggests the important role of miRNAs in cancer progression and therapeutic response. Here, we have established a radioresistant human GBM cell line U87R derived from parental U87 and found miR-135b expression was upregulated in U87R cells. miR-135b knockdown reversed radioresistance of U87R cells, and miR-135b overexpression enhanced radioresistance of U87 cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated GSK3β (Glycogen synthase kinase 3 beta) was a novel direct target of miR-135b. Moreover, GSK3β protein expression was downregulated in U87R cells and restored expression of GSK3β increased radiosensitivity of U87R cells. In addition, clinical data indicated that the expression of miR-135b or GSK3β was significantly association with IR resistance of GBM samples. Our findings suggest miR-135b is involved in the radioresistance of human GBM cells and miR-135b-GSK3β axis may be a novel candidate for developing rational therapeutic strategies for human GBM treatment.

The role of EGFR family inhibitors in muscle invasive bladder cancer: a review of clinical data and molecular evidence

PURPOSE

Conventional platinum based chemotherapy for advanced urothelial carcinoma is plagued by common resistance to this regimen. Several studies implicate the EGFR family of RTKs in urothelial carcinoma progression and chemoresistance. Many groups have investigated the effects of inhibitors of this family in patients with urothelial carcinoma. This review focuses on the underlying molecular pathways that lead to urothelial carcinoma resistance to EGFR family inhibitors.

MATERIALS AND METHODS

We performed a PubMed® search for peer reviewed literature on bladder cancer development, EGFR family expression, clinical trials of EGFR family inhibitors and molecular bypass pathways. Research articles deemed to be relevant were examined and a summary of original data was created. Meta-analysis of expression profiles was also performed for each EGFR family member based on data sets accessible via Oncomine®.

RESULTS

Many clinical trials using inhibitors of EGFR family RTKs have been done or are under way. Those that have concluded with results published to date do not show an added benefit over standard of care chemotherapy in an adjuvant or second line setting. However, a neoadjuvant study using erlotinib before radical cystectomy demonstrated promising results.

CONCLUSIONS

Clinical and preclinical studies show that for reasons not currently clear prior treatment with chemotherapeutic agents rendered patients with urothelial carcinoma with muscle invasive bladder cancer resistant to EGFR family inhibitors as well. However, EGFR family inhibitors may be of use in patients with no prior chemotherapy in whom EGFR or ERBB2 is over expressed.

Impact of ERBB2 mutations on in vitro sensitivity of bladder cancer to lapatinib

Lapatinib, a dual tyrosine kinase inhibitor of ErbB1 and ErbB2, shows a clinical benefit in a subset of patients with advanced urothelial bladder cancer (UBC). We hypothesized that the corresponding gene, ERBB2, is affected by mutations in a subset of UBC and that these mutations impact ErbB2 function, signaling, UBC proliferation, gene expression, and predict response to lapatinib. We found ERBB2 mutations in 5 of 33 UBC cell lines (15%), all of which were derived from invasive or high grade tumors. Phosphorylation and activation of ErbB2 and its downstream pathways were markedly enhanced in mutated cell lines compared with the ERBB2 wild-type. In addition, the gene expression profile was distinct, specifically for genes encoding for proteins of the extracellular matrix. RT112 cells infected with ERBB2 mutants showed a particular growth pattern ("mini-foci"). Upon treatment with lapatinib, 93% of these "mini-foci" were reversed. The sensitivity to lapatinib was greatest among cell lines with ERBB2 mutations. In conclusion, ERBB2 mutations occur in a subset of UBC and impact proliferation, signaling, gene expression and predict a greater response to lapatinib. If confirmed in the clinical setting, this may lead the way toward personalized treatment of a subset of UBC.

A comprehensive review of the preclinical efficacy profile of the ErbB family blocker afatinib in cancer

Afatinib (also known as BIBW 2992) has recently been approved in several countries for the treatment of a distinct type of epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer. This manuscript comprehensively reviews the preclinical data on afatinib, an irreversible inhibitor of the tyrosine kinase activity of members of the epidermal growth factor receptor family (ErbB) including EGFR, HER2 and ErbB4. Afatinib covalently binds to cysteine 797 of the EGFR and the corresponding cysteines 805 and 803 in HER2 and ErbB4, respectively. Such covalent binding irreversibly inhibits the tyrosine kinase activity of these receptors, resulting in reduced auto- and transphosphorylation within the ErbB dimers and inhibition of important steps in the signal transduction of all ErbB receptor family members. Afatinib inhibits cellular growth and induces apoptosis in a wide range of cells representative for non-small cell lung cancer, breast cancer, pancreatic cancer, colorectal cancer, head and neck squamous cell cancer and several other cancer types exhibiting abnormalities of the ErbB network. This translates into tumour shrinkage in a variety of in vivo rodent models of such cancers. Afatinib retains inhibitory effects on signal transduction and in vitro and in vivo cancer cell growth in tumours resistant to reversible EGFR inhibitors, such as those exhibiting the T790M mutations. Several combination treatments have been explored to prevent and/or overcome development of resistance to afatinib, the most promising being those with EGFR- or HER2-targeted antibodies, other tyrosine kinase inhibitors or inhibitors of downstream signalling molecules.

Preclinical and clinical development of afatinib: a focus on breast cancer and squamous cell carcinoma of the head and neck

ABSTRACT: Aberrant signaling of the ErbB family of receptors plays an integral role in the tumorigenesis of many cancer types, including head and neck squamous cell carcinoma (HNSCC) and breast cancer (BC). Significant research efforts have focused on developing new treatments that target ErbB family members, with the last decade seeing the approval of small-molecule tyrosine kinase inhibitors and monoclonal antibodies that inhibit ErbB signaling. However, treatment resistance is an ever-growing problem and, therefore, new therapies are being investigated to overcome this hurdle. Afatinib is an irreversible ErbB family blocker that has demonstrated potent anti-tumor activity in preclinical models and has displayed clinical efficacy in patients with non-small-cell lung cancer, and activity in HNSCC and BC. Here, the preclinical and clinical development of afatinib in the treatment of non-small-cell lung cancer, HNSCC and BC is described in the context of currently approved agents.

Genetic alterations in head and neck squamous cell carcinoma: The next-gen sequencing era

Head and neck squamous cell carcinoma is the sixth most common cancer in the world with approximately 650000 new cases diagnosed annually. Next-generation molecular techniques and results from phase 2 of the Cancer Genome Atlas becoming available have drastically improved our current knowledge on the genetics basis of head and neck squamous cell carcinoma. New insights and new perspectives on the mutational landscape implicated in head and neck squamous cell carcinoma provide improved tools for prognostication. More importantly, depend on the patient’s tumor subtypes and prognosis, deescalated or more aggressive therapy maybe chosen to achieve greater potency while minimizing the toxicity of therapy. This paper aims to review our current knowledge on the genetic mutations and altered molecular pathways in head and neck squamous cell carcinoma. Some of the most common mutations in head and neck squamous cell carcinoma reported by the cancer genome atlas including TP53, NOTCH1, Rb, CDKN2A, Ras, PIK3CA and EGFR are described here. Additionally, the emerging role of epigenetics and the role of human papilloma virus in head and neck squamous cell carcinoma are also discussed in this review. The molecular pathways, clinical applications, actionable molecular targets and potential therapeutic strategies are highlighted and discussed in details.

Evaluation of the antitumor activity of dacomitinib in models of human bladder cancer

Members of the human epidermal growth factor receptor (HER) family play a significant role in bladder cancer progression and may underlie the development of chemotherapy resistance. Dacomitinib is an irreversible tyrosine kinase inhibitor with structural specificity for the catalytic domains of epidermal growth factor receptor (EGFR), HER2 and HER4 that has exhibited vigorous efficacy against other solid tumors. We evaluated the antitumor activity of dacomitinib in human bladder cancer cell lines expressing varying levels of HER family receptors. These cell lines also were established as bladder cancer xenografts in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice to assess dacomitinib activity in vivo. Significant cytotoxic and cytostatic effects were noted in cells expressing elevated levels of the dacomitinib target receptors with apoptosis and cell cycle arrest being the predominant mechanisms of antitumor activity. Cells expressing lower levels of HER receptors were much less sensitive to dacomitinib. Interestingly, dacomitinib was more active than either trastuzumab or cetuximab in vitro, and exhibited increased growth inhibition of bladder tumor xenografts compared with lapatinib. Pharmacodynamic effects of dacomitinib included decreased E-cadherin (E-cad) expression, reduction of EGFR and extracellular signal-regulated kinase (ERK) phosphorylation and reduced mitotic count. Dacomitinib also inhibited tumor growth in a chemotherapy-resistant xenograft and, when combined with chemotherapy in a sensitive xenograft, exhibited superior antitumor effects compared with individual treatments. Evaluation in xenograft-bearing mice revealed that this combination was broadly feasible and well tolerated. In conclusion, dacomitinib exhibited pronounced activity both as a single agent and when combined with chemotherapy in human bladder cancer models. Further investigation of dacomitinib in the preclinical and clinical trial settings is being pursued.

EGFR inhibitors augment antitumour helper T-cell responses of HER family-specific immunotherapy

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a major cause of cancer-related morbidity and mortality worldwide. Epidermal growth factor receptor (EGFR)-targeted therapy is an attractive strategy alternative to conventional cancer treatments for HNSCC, but its efficacy remains controversial. T-cell-based immunotherapy has been proposed as a novel therapeutic approach to improve the clinical outcome for HNSCC. In this study, we report human epidermal receptor (HER) family epitopes that induced CD4 T-cell responses to HNSCC. The results provide support for a novel strategy to treat HNSCC by combining EGFR-targeted therapy with T-cell-based immunotherapy.

METHODS

We evaluated the capacity of predicted CD4 T-cell peptide epitopes from EGFR to induce antitumour immune responses in vitro. In addition, EGFR inhibitors were evaluated for their ability to augment tumour MHC class II expression in HNSCC cell lines and subsequently increase T-cell recognition.

RESULTS

Among several predicted peptide epitopes, EGFR875-889 elicited CD4 T-cell responses that were restricted by HLA-DR4, DR15, or DR53 molecules, indicating that the peptide functions as a promiscuous T-cell epitope. The peptide-reactive T cells responded to autologous dendritic cells loaded with EGFR-expressing tumour cell lysates, indicating that these epitopes are naturally processed. In addition, the CD4 T cells were capable of directly recognising and killing HNSCC cells expressing EGFR and the appropriate HLA class II molecule. T cells reactive with the EGFR875-889 epitope could be detected in the blood of HNSCC patients. EGFR875-889-reactive CD4 T cells were also able to recognise several peptide analogues derived from homologous regions of EGFR family members, HER-2, HER-3 and c-MET. Finally, we examined the effects of EGFR tyrosine kinase inhibition or EGFR-blocking antibodies on CD4 T-cell tumour reactivity. Treatment of tumour cells with the EGFR inhibitors enhanced tumour recognition by EGFR875-889-reactive T cells presumably due to the upregulation of HLA-DR expression in the HNSCC cells.

CONCLUSION

We identified novel CD4 T-cell EGFR epitopes and amongst these, EGFR875-889 functions as a promiscuous helper T-cell epitope that can elicit effective antitumour T-cell responses against tumours expressing HER family members and c-MET. These observations should facilitate the translation of T-cell-based immunotherapy into the clinic for the treatment of HNSCC and provide a rational basis for EGFR inhibition, immune-targeted combination therapy.

Novel targets in HPV-negative head and neck cancer: overcoming resistance to EGFR inhibition

Cancers of the head and neck that arise from habitual exposure to carcinogens have lower cure rates than those that arise from infection with human papillomavirus (HPV), and intensification of cytotoxic chemotherapy and radiation has not improved outcomes. HPV-negative head and neck cancers abundantly express EGFR, and the monoclonal antibody cetuximab, directed against EGFR, is the only targeted therapy that has improved disease survival so far. However, response rates to single-agent cetuximab are lower than 15%, and cetuximab given with chemotherapy or radiation leads to only a modest effect on survival. Thus, investigating the mechanisms of resistance to EGFR inhibition in HPV-negative head and neck cancer might help identify novel and active therapies. In this Review, we focus on therapies in development that target redundant receptor tyrosine kinases (eg, HER2 and MET), reduce or abrogate nuclear functions of EGFR, affect cellular trafficking by inhibition of histone deacetylase, or treatments that might address resistance that arises in the EGFR signalling stream (eg, aurora-kinase inhibitors and STAT decoys).

Epidermal growth factor receptor targeting in cancer: a review of trends and strategies

The epidermal growth factor receptor (EGFR) is a cell-surface receptor belonging to ErbB family of tyrosine kinase and it plays a vital role in the regulation of cell proliferation, survival and differentiation. However; EGFR is aberrantly activated by various mechanisms like receptor overexpression, mutation, ligand-dependent receptor dimerization, ligand-independent activation and is associated with development of variety of tumors. Therefore, specific EGFR inhibition is one of the key targets for cancer therapy. Two major approaches have been developed and demonstrated benefits in clinical trials for targeting EGFR; monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs). EGFR inhibitors like, cetuximab, panitumumab, etc. (mAbs) and gefitinib, erlotinib, lapatinib, etc. (TKIs) are now commercially available for treatment of variety of cancers. Recently, many other agents like peptides, nanobodies, affibodies and antisense oligonucleotide have also shown better efficacy in targeting and inhibiting EGFR. Now a days, efforts are being focused to identify molecular markers that can predict patients more likely to respond to anti-EGFR therapy; to find out combinatorial approaches with EGFR inhibitors and to bring new therapeutic agents with clinical efficacy. In this review we have outlined the role of EGFR in cancer, different types of EGFR inhibitors, preclinical and clinical status of EGFR inhibitors as well as summarized the recent efforts made in the field of molecular EGFR targeting.