The role of epidermal growth factor receptor in head and neck squamous cell carcinoma

Insights into metastatic roadmap of head and neck cancer squamous cell carcinoma based on clinical, histopathological and molecular profiles

The incidence of head and neck cancer (HNC), constituting approximately one in ten cancer cases worldwide, affects approximately 644,000 individuals annually. Managing this complex disease involves various treatment modalities such as systemic therapy, radiation, and surgery, particularly for patients with locally advanced disease. HNC treatment necessitates a multidisciplinary approach due to alterations in patients' genomes affecting their functionality. Predominantly, squamous cell carcinomas (SCCs), the majority of HNCs, arise from the upper aerodigestive tract epithelium. The epidemiology, staging, diagnosis, and management techniques of head and neck squamous cell carcinoma (HNSCC), encompassing clinical, image-based, histopathological and molecular profiling, have been extensively reviewed. Lymph node metastasis (LNM) is a well-known predictive factor for HNSCC that initiates metastasis and significantly impacts HNSCC prognosis. Distant metastasis (DM) in HNSCC has been correlated to aberrant expression of cancer cell-derived cytokines and growth factors triggering abnormal activation of several signaling pathways that boost cancer cell aggressiveness. Recent advances in genetic profiling, understanding tumor microenvironment, oligometastatic disease, and immunotherapy have revolutionized treatment strategies and disease control. Future research may leverage genomics and proteomics to identify biomarkers aiding individualized HNSCC treatment. Understanding the molecular basis, genetic landscape, atypical signaling pathways, and tumor microenvironment have enhanced the comprehension of HNSCC molecular etiology. This critical review sheds light on regional and distant metastases in HNSCC, presenting major clinical and laboratory features, predictive biomarkers, and available therapeutic approaches.

First Clinical Results of Fluorescence Lifetime-enhanced Tumor Imaging Using Receptor-targeted Fluorescent Probes

PURPOSE

Fluorescence molecular imaging, using cancer-targeted near infrared (NIR) fluorescent probes, offers the promise of accurate tumor delineation during surgeries and the detection of cancer specific molecular expression in vivo. However, nonspecific probe accumulation in normal tissue results in poor tumor fluorescence contrast, precluding widespread clinical adoption of novel imaging agents. Here we present the first clinical evidence that fluorescence lifetime (FLT) imaging can provide tumor specificity at the cellular level in patients systemically injected with panitumumab-IRDye800CW, an EGFR-targeted NIR fluorescent probe.

EXPERIMENTAL DESIGN

We performed wide-field and microscopic FLT imaging of resection specimens from patients injected with panitumumab-IRDye800CW under an FDA directed clinical trial.

RESULTS

We show that the FLT within EGFR-overexpressing cancer cells is significantly longer than the FLT of normal tissue, providing high sensitivity (>98%) and specificity (>98%) for tumor versus normal tissue classification, despite the presence of significant nonspecific probe accumulation. We further show microscopic evidence that the mean tissue FLT is spatially correlated (r > 0.85) with tumor-specific EGFR expression in tissue and is consistent across multiple patients. These tumor cell-specific FLT changes can be detected through thick biological tissue, allowing highly specific tumor detection and noninvasive monitoring of tumor EFGR expression in vivo.

CONCLUSIONS

Our data indicate that FLT imaging is a promising approach for enhancing tumor contrast using an antibody-targeted NIR probe with a proven safety profile in humans, suggesting a strong potential for clinical applications in image guided surgery, cancer diagnostics, and staging.

Exposure to chewing tobacco promotes primary oral squamous cell carcinoma and regional lymph node metastasis by alterations of SDF1α/CXCR4 axis

A high incidence of oral squamous cell carcinoma (OSCC) is observed in South-East Asian countries due to addictions such as chewing tobacco. Local invasion and distant metastases are primary causes of poor prognosis in OSCC. This study aimed to understand the alterations in metastasis biomarkers, such as stromal cell-derived factor-1α (SDF-1 or SDF1α) and its receptor C-X-C chemokine receptor type 4 (CXCR4), in OSCC patient samples that were stratified based on the history of addiction to chewing tobacco. Targeted immunohistochemical staining and Western blotting were performed on primary tumour and metastatic lymph node (LN) tissues in parallel. Overexpression of hepatocyte growth factor (HGF), activated form of its cognate receptor tyrosine kinase, c-Met (p-Met), GRB2-associated-binding protein 1 (Gab1), phospho-protein kinase B (pAkt), nuclear factor kappa B (NF-κB) and cyclooxygenase-2 (COX-2) were observed in primary tumour and metastatic lymph nodes in both chewer and non-chewer cohorts. Variance analysis showed significant positive correlation between them (P < .0001) indicating upregulation of these biomarkers upon ligand-induced activation of c-Met in both tobacco chewers and non-chewers. Significantly higher expressions of SDF1α and CXCR4 were observed in both primary tumours and metastatic lymph nodes of tobacco chewers (P < .0001) and coincided with overexpressed HGF. In contrast, no significant correlation was observed between expression of HGF and that of SDF1α and CXCR4 in non-chewers. Together, our findings provide important insights into the association of HGF/c-Met and the SDF1α/CXCR4 axis in lymph node metastasis and to an aetiological link with the habit of chewing tobacco.

Taiwanin C elicits apoptosis in arecoline and 4-nitroquinoline-1-oxide-induced oral squamous cell carcinoma cells and hinders proliferation via epidermal growth factor receptor/PI3K suppression

Oral Squamous Cell Carcinoma (OSSC) is a major life-threatening disease with high incidence in the Southeast Asian countries. Chronic exposure to arecoline causes genetic changes in the epithelial cells of the oral mucosa, induces proliferation through activation of the EGF receptor and promotes downstream COX-2 expression. Taiwanin C, a podophyllotoxin derived from Taiwania cryptomerioides Hayata is known to inhibit COX activity and to hinder PGE2 production in macrophages. In this study a tumor cell line T28 and a non-tumor cell line N28 derived from mice OSCC models were used to study the effect of Taiwanin C on PGE₂ associated COX-2 expression and cell cycle regulators. Taiwanin C activated p21 protein expression, down-regulated cell cycle regulatory proteins, elevated apoptosis and down-regulated p-PI3K/p-Akt survival mechanism in T28 oral cancer cells. Our results therefore emphasize the therapeutic potential of Taiwanin C against arecoline-induced oral cancer.

Precision Therapy of Head and Neck Squamous Cell Carcinoma

Precision medicine is an approach to disease prevention and treatment that takes into account genetic variability and environmental and lifestyle influences that are unique to each patient. It facilitates stratification of patient populations that vary in their susceptibility to disease and response to therapy. Shared databases and the implementation of new technology systems designed to advance the integration of this information will enable health care providers to more accurately predict and customize prevention and treatment strategies for patients. Although precision medicine has had a limited impact in most areas of medicine, it has been shown to be an increasingly successful approach to cancer therapy. Despite early promising results targeting aberrant signaling pathways or inhibitors designed to block tumor-driven processes such as angiogenesis, limited success emphasizes the need to discover new biomarkers and treatment targets that are more reliable in predicting response to therapy and result in better health outcomes. Recent successes in the use of immunity-inducing antibodies have stimulated increased interest in the use of precision immunotherapy of head and neck squamous cell carcinoma. Using next-generation sequencing, the precise profiling of tumor-infiltrating lymphocytes has great promise to identify hypoimmunogenic cancer that would benefit from a rationally designed combinatorial approach. Continued interrogation of tumors will reveal new actionable targets with increasing therapeutic efficacy and fulfill the promise of precision therapy of head and neck cancer.

Hepatocyte Growth Factor/c-Met Signaling in Head and Neck Cancer and Implications for Treatment

Aberrant signaling of the hepatocyte growth factor (HGF)/c-Met pathway has been identified as a promoter of tumorigenesis in several tumor types including head and neck squamous cell carcinoma (HNSCC). Despite a relatively low c-Met mutation frequency, overexpression of HGF and its receptor c-Met has been observed in more than 80% of HNSCC tumors, with preclinical and clinical studies linking overexpression with cellular proliferation, invasion, migration, and poor prognosis. c-Met is activated by HGF through a paracrine mechanism to promote cellular morphogenesis enabling cells to acquire mesenchymal phenotypes in part through the epithelial-mesenchymal transition, contributing to metastasis. The HGF/c-Met pathway may also act as a resistance mechanism against epidermal growth factor receptor (EGFR) inhibition in advanced HNSCC. Furthermore, with the identification of a biologically distinct subset of HNSCC tumors acquired from human papillomavirus (HPV) infection that generally portends a good prognosis, high expression of HGF or c-Met in HPV-negative tumors has been associated with worse prognosis. Dysregulated HGF/c-Met signaling results in an aggressive HNSCC phenotype which has led to clinical investigations for targeted inhibition of this pathway. In this review, HGF/c-Met signaling, pathway alterations, associations with clinical outcomes, and preclinical and clinical therapeutic strategies for targeting HGF/c-Met signaling in HNSCC are discussed.

The prognostic value of Tiam1 protein expression in head and neck squamous cell carcinoma: a retrospective study

Introduction

Head and neck squamous cell carcinoma (HNSCC) is a common cancer worldwide and has a poor prognosis. A biomarker predicting the clinical outcome of HNSCC patients could be useful in guiding treatment planning. Overexpression of the T lymphoma invasion and metastasis 1 (Tiam1) protein has been implicated in the migration and invasion of neoplasms. However, its role in HNSCC progression needs to be further validated. We detected the expression of Tiam1 in normal and tumor tissues and determined its association with clinical outcomes in patients with HNSCC.

Methods

We measured the expression of Tiam1 in normal and cancerous tissue samples from the patients with HNSCC treated at Sun Yat-sen University Cancer Center between 2001 and 2008. The Tiam1 expression was scored from 0 to 12 based on the percentage of positively stained cells and the staining intensity. We then determined the diagnostic performance of this score in predicting overall survival (OS) and disease-free survival (DFS).

Results

Of the 194 evaluable patients, those with advanced disease, lymph node metastasis at diagnosis, and recurrence or metastasis during follow-up had a higher tendency of having high Tiam1 expression as compared with their counterparts (P < 0.05). The proportion of samples with high Tiam1 expression was also higher in cancerous tissues than in non-cancerous tissues (57.7% vs. 13.9%, P < 0.001). Cox proportional hazards regression analysis revealed that Tiam1 expression scores of 5 and greater independently predicted short OS and DFS.

Conclusion

The Tiam1 expression is shown as a promising biomarker of clinical outcomes in patients with HNSCC and should be evaluated in prospective trials.

Translational genomics and head and neck cancer: toward precision medicine

Head and neck squamous cell carcinoma (HNSCC) comprise a wide spectrum of neoplasms with different tumor biologies, prognosis and response to therapies. Current tumor classification and traditional diagnostic methods (e.g. clinical assessment, histopathology) are limited in their capacity to determine prognosis and clinical decision-making. Despite recent improvements in treatment, the outcome for patients with HNSCC remains poor. Similar to most tumors, several patient-related factors, (e.g. genetics and environment) and disease-related factors (e.g. tumor location, TMN staging) play a significant role on survival. Thus, the problem in defining the prognosis is that the clinical course and response to treatment differ considerably among patients. Such interindividual variability is related to the heterogeneity of the tumor, genetic and epigenetic variations, thus reflecting the interaction of multiple biological components that result in a unique phenotype. Integrative genomics are developed to identify the molecular pathways leading to cancer at the individual level and find novel prognostic markers for HNSCC, hence tailoring a treatment accordingly. Such genetic-based personalized diagnosis allows tumor stratification and implementation of targeted therapy. Modern medicine includes new drugs that disrupt the implicated molecules and their signaling pathways. Here, we summarize the current state of knowledge that elucidates the translation of genetic data into clinical benefit.

Preclinical comparison of near-infrared-labeled cetuximab and panitumumab for optical imaging of head and neck squamous cell carcinoma

PURPOSE

Though various targets have been proposed and evaluated, no agent has yet been investigated in a clinical setting for head and neck cancer. The present study aimed to compare two fluorescently labeled anti-epidermal growth factor receptor (EGFR) antibodies for detection of head and neck squamous cell carcinoma (HNSCC).

PROCEDURES

Antigen specificities and in vitro imaging of the fluorescently labeled anti-EGFR antibodies were performed. Next, immunodeficient mice (n = 22) bearing HNSCC (OSC-19 and SCC-1) tongue tumors received systemic injections of cetuximab-IRDye800CW, panitumumab-IRDye800CW, or IgG-IRDye800CW (a nonspecific control). Tumors were imaged and resected using two near-infrared imaging systems, SPY and Pearl. Fluorescent lymph nodes were also identified, and all resected tissues were sent for pathology.

RESULTS

Panitumumab-IRDye800CW and cetuximab-IRDye800CW had specific and high affinity binding for EGFR (K D = 0.12 and 0.31 nM, respectively). Panitumumab-IRDye800CW demonstrated a 2-fold increase in fluorescence intensity compared to cetuximab-IRDye800CW in vitro. In vivo, both fluorescently labeled antibodies produced higher tumor-to-background ratios compared to IgG-IRDye800CW. However, there was no significant difference between the two in either cell line or imaging modality (OSC-19: p = 0.08 SPY, p = 0.48 Pearl; SCC-1: p = 0.77 SPY, p = 0.59 Pearl; paired t tests).

CONCLUSIONS

There was no significant difference between the two fluorescently labeled anti-EGFR monoclonal antibodies in murine models of HNSCC. Both cetuximab and panitumumab can be considered suitable targeting agents for fluorescent intraoperative detection of HNSCC.

Tbx3 represses PTEN and is over-expressed in head and neck squamous cell carcinoma

Background

Despite advances in diagnostic and treatment strategies, head and neck squamous cell cancer (HNSCC) constitutes one of the worst cancer types in terms of prognosis. PTEN is one of the tumour suppressors whose expression and/or activity have been found to be reduced in HNSCC, with rather low rates of mutations within the PTEN gene (6-8%). We reasoned that low expression levels of PTEN might be due to a transcriptional repression governed by an oncogene. Tbx2 and Tbx3, both of which are transcriptional repressors, have been found to be amplified or over-expressed in various cancer types. Thus, we hypothesize that Tbx3 may be over expressed in HNSCC and may repress PTEN, thus leading to cancer formation and/or progression.

Methods

Using immunohistochemistry and quantitative PCR (qPCR), protein and mRNA levels of PTEN and Tbx3 were identified in samples excised from cancerous and adjacent normal tissues from 33 patients who were diagnosed with HNSCC. In addition, HeLa and HEK cell lines were transfected with a Tbx3 expressing plasmid and endogenous PTEN mRNA and protein levels were determined via qPCR and flow cytometry. Transcription assays were performed to demonstrate effects of Tbx3 on PTEN promoter activity. Mann–Whitney, Spearman’s Correlation and Wilcoxon signed-rank tests were used to analyze the data.

Results

We demonstrate that in HNSCC samples, Tbx3 mRNA levels are increased with respect to their normal tissue counterparts (p<0.001), whereas PTEN mRNA levels are significantly reduced in cancer tissues. Moreover, Tbx3 protein is also increased in HNSCC tissue sections. Over-expression of Tbx3 in HeLa and HEK cell lines causes reduction in endogenous PTEN mRNA and protein levels. In addition, transcription activity assays reveal that Tbx3 is capable of repressing both the basal and induced promoter activity of PTEN.

Conclusions

We show that Tbx3 is up-regulated in tissue samples of HNSCC patients and that Tbx3 represses PTEN transcription. Thus, our data not only reveals a new mechanism that may be important in cancer formation, but also suggests that Tbx3 can be used as a potential biomarker in cancer.

Molecular-targeted therapies in head and neck cancer

The increasing understanding of tumor biology has opened the door to a new class of biological agents directed at specific molecular targets in the treatment of squamous cell carcinomas of the head and neck. These targeted agents present the opportunity to more effectively attack the crucial cellular pathways contributing to tumor growth and survival, while minimizing toxicity. Cetuximab, which targets epidermal growth factor (EGF) receptor signaling, was the first such biological agent to be proven effective in head and neck squamous cell cancers. Currently, there are dozens of targeted agents at various stages of testing for use in the treatment of head and neck cancers. In this article, we review strategies aimed at key pathways, including EGF receptor signaling, the Vascular Endothelial Growth Factor (VEGF) pathway, and PI3K/AKT/mammalian target of rapamycin activation.

The role of cetuximab in the management of head and neck cancers

INTRODUCTION

The standard of care for patients with locally-advanced head and neck cancer is chemoradiation or surgical resection followed by radiation treatment with or without chemotherapy and despite aggressive, multimodality therapies with their associated toxicities, attempts are being made to improve efficacy while reducing toxicity. Cetuximab is a chimeric mAb directed against the EGFR that showed clinical activity in squamous cell carcinoma of head and neck (SCCHN).

AREAS COVERED

Cetuximab is beneficial in recurrent and metastatic setting, as well as in the definitive setting. In a landmark study by Bonner et al., cetuximab was found to be effective in prolonging survival in conjunction with radiation treatment in locally-advanced tumors versus radiation therapy alone. The Erbitux in First-Line Treatment of Recurrent or Metastatic Head and Neck Cancer (EXTREME) trial also showed an improvement in conjunction with chemotherapy in recurrent and metastatic tumors.

EXPERT OPINION

Cetuximab is an important therapeutic option in SSCHN, and will continue to be used in metastatic and definitive settings. While cetuximab is a valuable tool in the treatment of SCCHN, more studies are needed to maximize the efficacy of this mAb in clinical settings and to identify the subpopulation of patients that truly benefit from its use.

Molecularly targeted therapies in head and neck cancers

Head and neck cancers (HNC) are 6th most common malignancies according to the incidence rate. Over 85% of tumors of this region are epithelial tumors, especially squamous cell carcinomas (head and neck squamous cell carcinomas - HNSCC). Surgery, chemotherapy and radiotherapy are still the standard for the treatment of HNC. Despite the great development of the various methods of treatment, survival of patients have not improved significantly over the last 30 years, with the overall, 5-year survival not exceeding 50%. Progress in understanding the biology of cancer leads to personalization of therapy and introduction of drugs with molecular mechanism of action to everyday practice. At present, the effectiveness of monoclonal antibodies against EGFR in the treatment of HNSCC has already been proven. Cetuximab in combination with radiotherapy was found to be effective in patients with advanced and locally advanced HNSCC. There are also some promising results of phase III trials with zalutumumab and panitumumab. Initial efficacy of sorafenib (an inhibitor of the intracellular domain of VEGFR, PDGFR and c-Kit) and afatinib (an irreversible inhibitor of pan-HER tyrosine kinase) have been demonstrated. Great hopes for the future are linked with the potential use of STAT3, EGFRvIII, abnormal proteins K-ras, H-ras and PTEN as well as proteasome as a target for therapy.

Diverse effects of combined radiotherapy and EGFR inhibition with antibodies or TK inhibitors on local tumour control and correlation with EGFR gene expression

PURPOSE

To compare functional effects of combined irradiation and EGFR inhibition in different HNSCC tumour models in vivo with the results of molecular evaluations, aiming to set a basis for the development of potential biomarkers for local tumour control.

MATERIAL AND METHODS

In five HNSCC tumour models, all wild-type for EGFR and KRAS, the effect of radiotherapy alone (30 fractions/6 weeks) and with simultaneous cetuximab or erlotinib treatment on local tumour control were evaluated and compared with molecular data on western blot, immunohistochemistry and fluorescence-in situ-hybridisation (FISH).

RESULTS

Erlotinib and cetuximab alone significantly prolonged tumour growth time in 4/5 tumour models. Combined irradiation and cetuximab treatment significantly improved local tumour control in 3/5 tumour models, whereas erlotinib did not alter local tumour control in any of the tumour models. The amount of the cetuximab-effect on local tumour control significantly correlated with the EGFR/CEP-7 ratios obtained by FISH.

CONCLUSION

Both drugs prolonged growth time in most tumour models, but only application of cetuximab during irradiation significantly improved local tumour control in 3/5 tumour models. The significant correlation of this curative effect with the genetic EGFR expression measured by FISH will be further validated in preclinical and clinical studies.

Phosphoproteomic analysis of signaling pathways in head and neck squamous cell carcinoma patient samples

Molecular targeted therapy represents a promising new strategy for treating cancers because many small-molecule inhibitors targeting protein kinases have recently become available. Reverse-phase protein microarrays (RPPAs) are a useful platform for identifying dysregulated signaling pathways in tumors and can provide insight into patient-specific differences. In the present study, RPPAs were used to examine 60 protein end points (predominantly phosphoproteins) in matched tumor and nonmalignant biopsy specimens from 23 patients with head and neck squamous cell carcinoma to characterize the cancer phosphoproteome. RPPA identified 18 of 60 analytes globally elevated in tumors versus healthy tissue and 17 of 60 analytes that were decreased. The most significantly elevated analytes in tumor were checkpoint kinase (Chk) 1 serine 345 (S345), Chk 2 S33/35, eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) S65, protein kinase C (PKC) ζ/ι threonine 410/412 (T410/T412), LKB1 S334, inhibitor of kappaB alpha (IκB-α) S32, eukaryotic translation initiation factor 4E (eIF4E) S209, Smad2 S465/67, insulin receptor substrate 1 (IRS-1) S612, mitogen-activated ERK kinase 1/2 (MEK1/2) S217/221, and total PKC ι. To our knowledge, this is the first report of elevated PKC ι in head and neck squamous cell carcinoma that may have significance because PKC ι is an oncogene in several other tumor types, including lung cancer. The feasibility of using RPPA for developing theranostic tests to guide personalized therapy is discussed in the context of these data.

High SEPT9_v1 Expression Is Associated with Poor Clinical Outcomes in Head and Neck Squamous Cell Carcinoma

The purpose of this work was to determine SEPT9_v1 expression levels in head and neck squamous cell carcinoma (HNSCC) and to analyze whether SEPT9_v1 expression is relevant to clinical outcomes. Recently, the SEPT9 isoform SEPT9_v1 has been implicated in oncogenesis, and methylation of the SEPT9 promoter region was reported in HNSCC. These findings led us to hypothesize that SEPT9_v1 could be differently expressed in HNSCC. To determine whether SEPT9_v1 is expressed in HNSCC, tissue microarray immunohistochemical analysis was performed using a SEPT9_v1-specific antibody. Tissue microarrays stained with a polyclonal SEPT9_v1-specific antibody was used to determine protein expression levels in HNSCC tissue samples, some with known clinical outcomes. This analysis showed that SEPT9_v1 is in fact highly expressed in HNSCC compared with normal epithelium, and high expression levels directly correlated with poor clinical outcomes. Specifically, a high SEPT9_v1 expression was associated with decreased disease-specific survival (P = .012), time to indication of surgery at primary site (P = .008), response to induction chemotherapy (P = .0002), and response to chemotherapy (P = .02), as well as advanced tumor stage (P = .012) and N stage (P = .0014). The expression of SEPT9_v1 was also strongly correlated with smoking status (P = .00094). SEPT9_v1 is highly expressed in HNSCC, and a high expression of SEPT9_v1 is associated with poor clinical outcomes. These data indicate that SEPT9_v1 warrants additional investigation as a potential biomarker for HNSCC.

Transactivation and expression patterns of Jun and Fos/AP-1 super-family proteins in human oral cancer

Transcription factor activator protein-1 (AP-1) super-family is known to modulate expression of array of genes during development of many cancers and considered as an important target for modern therapeutics. But the role of AP-1 during development of human oral cancers is still poorly understood. Because oral cancer is one of the most common cancers in India and south-east Asia, we studied the activation and expression pattern of AP-1 family of proteins and mRNA in different stages of oral carcinogenesis. Gel-shift assay, western blotting, immunohistochemistry and northern blotting have been used to assess the binding activity and expression pattern of AP-1 family (c-Jun, JunB, JunD, c-Fos, FosB, Fra-1 and Fra-2) proteins and mRNA transcripts in a total of 100 fresh oral tissue specimens comprising precancer (n = 40), cancer (n = 50) and healthy control (n = 10). Constitutive activation of AP-1 with concomitant upregulated expression of majority of AP-1 family of proteins and mRNA was observed in cancer cases. Interestingly, almost all precancerous cases showed JunD homodimers, whereas c-Fos/JunD was the most prevalent complex found in cancer tissues. The overexpression of EGFR mRNA, p50:p50/NF-kappaB homodimer formation, together with overexpression of pERK and c-Fos proteins in this study suggests an interesting cross talk between AP-1 and NF-kappaB pathways in oral cancers. Thus, this study demonstrates differential expression and activation of AP-1 super-family proteins in relation to severity of lesion and their crucial role in human oral carcinogenesis.

Identification of epidermal growth factor receptor (EGFR) exon 20 single nucleotide polymorphism in Chinese squamous cell carcinoma of head and neck (SCCHN)

CONCLUSION

The 78th single nucleotide polymorphism (SNP) in exon 20 of epidermal growth factor receptor (EGFR) might be a predictor of the clinical course of squamous cell carcinoma of the head and neck (SCCHN), and genetic predisposition could influence the progression of SCCHN in Chinese subjects.

OBJECTIVE

To analyze the clinical significance of EGFR SNP in Chinese SCCHN patients.

MATERIALS AND METHODS

Direct sequencing of exons 18-21 was used to analyze somatic mutations of EGFR. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to evaluate the expression level of EGFR. The chi-square test and Kaplan-Meier method were the main statistical methods used to analyze the correlation of the investigated variables and prognostic significance.

RESULTS

In analyzing exons 18-21 of EGFR in 96 patients with SCCHN, only one SNP was found in the 78th site of exon 20 and it mostly existed in specimens coming from the hypopharynx. Further statistical analysis showed that among the clinical or histopathologic parameters, the 78th SNP had a close relationship with earlier stage and more localized primary carcinoma, while at present the analysis did not support the proposition that the SNP was an independent prognostic factor.

Inhibition of Mammalian target of rapamycin by rapamycin causes the regression of carcinogen-induced skin tumor lesions

PURPOSE

The activation of Akt/mammalian target of rapamycin (mTOR) pathway represents a frequent event in squamous cell carcinoma (SCC) progression, thus raising the possibility of using specific mTOR inhibitors for the treatment of SCC patients. In this regard, blockade of mTOR with rapamycin prevents the growth of human head and neck SCC cells when xenotransplanted into immunodeficient mice. However, therapeutic responses in xenograft tumors are not always predictive of clinical anticancer activity.

EXPERIMENTAL DESIGN

As genetically defined and chemically induced animal cancer models often reflect better the complexity of the clinical setting, we used here a two-step chemical carcinogenesis model to explore the effectiveness of rapamycin for the treatment of skin SCC.

RESULTS

Rapamycin exerted a remarkable anticancer activity in this chemically induced cancer model, decreasing the tumor burden of mice harboring early and advanced tumor lesions, and even recurrent skin SCCs. Immunohistochemical studies on tumor biopsies and clustering analysis revealed that rapamycin causes the rapid decrease in the phosphorylation status of mTOR targets followed by the apoptotic death of cancer cells and the reduction in the growth and metabolic activity of the surviving ones, concomitant with a decrease in the population of cancer cells expressing mutant p53. This approach enabled investigating the relationship among molecular changes caused by mTOR inhibition, thus helping identify relevant biomarkers for monitoring the effectiveness of mTOR inhibition in the clinical setting.

CONCLUSIONS

Together, these findings provide a strong rationale for the early evaluation of mTOR inhibitors as a molecular targeted approach to treat SCC.

Fluorescent labeled anti-EGFR antibody for identification of regional and distant metastasis in a preclinical xenograft model

BACKGROUND

Detection of regional and distant metastatic disease has significant implications for patient management. Fluorescent imaging may be a useful technique for metastasis detection and removal.

METHODS

Anti-epidermal growth factor receptor antibody (cetuximab) and isotype-matched control antibody (immunoglobulin G [IgG]) were labeled with a near-infrared fluorophore (Cy5.5), then systemically administered to mice with tumors resulting from either intraoral or intravenous injections of head and neck squamous cell carcinoma. Mice were sacrificed before undergoing fluorescent stereomicroscopy to assess pulmonary or cervical lymph node metastasis. Fluorescent areas were serially excised until wound bed demonstrated negative fluorescence.

RESULTS

Mice bearing pulmonary metastases displayed diffuse background after IgG-Cy5.5 injection, but demonstrated a speckled fluorescent pattern across lung surface following cetuximab-Cy5.5 injection. Mice bearing cervical metastases demonstrated clear fluorescence of primary tongue tumor and bilateral cervical nodes. Fluorescence correlated with histopathology.

CONCLUSION

These data suggest that cetuximab-Cy5.5 may have clinical utility in the detection and guided the removal of regional and distant micrometastasis.

ErbB receptors in the biology and pathology of the aerodigestive tract

The most common sites of malignancies in the aerodigestive tract include the lung, head and neck and the esophagus. Esophageal adenocarcinomas (EA), esophageal squamous cell carcinomas (ESCC), and squamous cell carcinomas of the head and neck (SCCHN) are the primary focus of this review. Traditional treatment for aerodigestive tract cancers includes primary chemoradiotherapy (CRT) or surgical resection followed by radiation (or CRT). Recent developments in treatment have focused increasingly on molecular targeting strategies including cetuximab (a monoclonal antibody against epidermal growth factor receptor (EGFR)). Cetuximab was FDA approved in 2006 for treatment of SCCHN, underscoring the importance of understanding the biology of these malignancies. EGFR is a member of the ErbB family of growth factor receptor tyrosine kinases. The major pathways activated by ErbB receptors include Ras/Raf/MAPK; PI3K/AKT; PLCgamma and STATs, all of which lead to the transcription of target genes that may contribute to aerodigestive tumor progression. This review explores the expression of ErbB receptors in EA, ESCC and SCCHN and the signaling pathways of EGFR in SCCHN.

A signal network involving coactivated NF-kappaB and STAT3 and altered p53 modulates BAX/BCL-XL expression and promotes cell survival of head and neck squamous cell carcinomas

Abrogation of apoptosis to sustain cell survival is an essential step in development of cancer. Aberrant activation of signal transcription factors NF-kappaB or STAT3, alterations in p53 status, or BCL/BAX family expression have each been reported to affect cell survival in cancer, including head and neck squamous cell carcinomas (HNSCC). However, molecular targeting of these alterations individually has yielded disappointing results. In our study, we examined the hypothesis that alterations in a signal network involving NF-kappaB, STAT3 and p53 modulates expression of proapoptotic BAX and antiapoptotic BCL-XL proteins, and promotes cell survival of HNSCC. We found that NF-kappaB and STAT3 are coactivated together, and with cytokine stimulation or siRNA knock-down, both modulate BAX/BCL-XL. Greater modulation among HNSCC lines expressing low wt p53 than those over-expressing mt p53 protein suggested that decreased p53 expression might enhance activation of NF-kappaB, STAT3 and BCL-XL. Reexpression of wt p53 suppressed NF-kappaB and STAT3 nuclear binding activity, and BCL-XL expression, while inducing p21 and BAX. Over-expression of p53 together with inhibition of NF-kappaB or STAT3 induced greater increase in the BAX/BCL-XL ratio and apoptosis than modulation of these transcription factors individually. Conversely, NF-kappaB or STAT3 inducing cytokines decreased the BAX/BCL-XL ratio. Thus, a network involving signal coactivation of NF-kappaB and STAT3, differentially modified by p53 inactivation or mutation, promotes altered BAX/BCL-XL expression and cell survival in HNSCC. Inhibition of signal activation of both NF-kappaB and STAT3 together with reexpression of p53 could be the most effective strategy to restore BAX/BCL-XL regulation and for cytotoxic therapy of HNSCC.

Prediction of chemosensitivity using multigene analysis in head and neck squamous cell carcinoma

AIMS

The main purpose of the current study was to find predictive biomarkers that can be routinely used for the response to chemotherapy in head and neck squamous cell carcinoma (HNSCC).

METHODS

From this standpoint, we selected the histoculture drug response assay (HDRA) to assess in vitro chemosensitivity, and real-time reverse transcription polymerase chain reaction to investigate the gene expression profile of individual tumors as available predictive biomarkers. Using both surgery and biopsy specimens, we analyzed their gene expression profiles using the 18 markers that we thought were likely predictors of the response to anti-cancer agents.

RESULTS

Statistically significant associations were found between 5-fluorouracil (5-FU) sensitivity in HDRA and HER-2 mRNA expression level (p = 0.0030). Moreover, HER-2 expression was significantly associated with cisplatin sensitivity (p = 0.0089). Cisplatin sensitivity in HDRA was also demonstrated to have a significant association with epidermal growth factor receptor (EGFR) expression in which the group with cisplatin resistance tended to have a higher expression level than the sensitive group (p = 0.0385).

CONCLUSION

HER-2 and EGFR may be possible reliable predictive biomarkers for anti-cancer therapy, and might help in the decision-making process for individual patients with HNSCC.

A retroinhibition approach reveals a tumor cell-autonomous response to rapamycin in head and neck cancer

Emerging evidence supporting the activation of the Akt-mammalian target of rapamycin (mTOR) signaling network in head and neck squamous cell carcinoma (HNSCC) progression has provided the rationale for exploring the therapeutic potential of inhibiting this pathway for HNSCC treatment. Indeed, rapamycin, a clinically relevant mTOR inhibitor, promotes the rapid regression of HNSCC-tumor xenografts in mice. However, rapamycin does not affect the growth of HNSCC cells in vitro, thus raising the possibility that, as for other cancer types, rapamycin may not target cancer cells directly but may instead act on a component of the tumor microenvironment, such as tumor-associated vasculature. Here, we used a retroinhibition approach to assess the contribution of cancer cell-autonomous actions of rapamycin to its antitumor activity in HNSCC. A rapamycin-resistant form of mTOR (mTOR-RR) was expressed in HNSCC cells while retaining the wild-type (rapamycin-sensitive) mTOR (mTOR-WT) alleles in host-derived endothelial and stromal cells. Expression of mTOR-RR prevented the decrease in phospho-S6 levels caused by rapamycin through mTOR in HNSCC cells but not in stromal cells, and rendered HNSCC xenografts completely resistant to the antitumoral activity of rapamycin. This reverse pharmacology strategy also enabled monitoring the direct consequences of inhibiting mTOR in cancer cells within the complex tumor microenvironment, which revealed that mTOR controls the accumulation of hypoxia-inducible factor-1 alpha (HIF-1 alpha) and the consequent expression of vascular endothelial growth factor and a glucose transporter, Glut-1, in HNSCC cells. These findings indicate that HNSCC cells are the primary target of rapamycin in vivo, and provide evidence that its antiangiogenic effects may represent a downstream consequence of mTOR inhibition in HNSCC cells.

Aberrant kinase signaling: lessons from head and neck cancer

Cancers, including head and neck squamous cell carcinoma (HNSCC), are characterized by the increased expression of receptor and nonreceptor tyrosine kinases. Many small molecules have been developed that selectively inhibit these kinases. These drugs have demonstrated antitumor effects in many preclinical cancer models and are now either approved for use in selected cancer patients or are under active clinical development. Receptor tyrosine kinases can also be targeted using monoclonal antibodies. Cetuximab is a chimeric antibody that inhibits the epidermal growth factor receptor and was approved for use in HNSCC, making it the first new drug for the treatment of this malignancy in over 40 years. Serine/threonine kinases are also aberrantly expressed in HNSCC and inhibitors of these kinases are being developed for clinical use. These developments will allow for the rational design of treatment regimens for HNSCC patients based on the aberrant kinase signaling in their tumors.

Mouse models for human head and neck squamous cell carcinomas

Mouse models of human cancer play an important role in understanding the mechanisms of carcinogenesis and have accelerated the search for finding new molecular targets for cancer therapy. However, genetically engineered mouse models for head and neck squamous cell carcinoma (HNSCC) have only recently overcome major technical obstacles and begun to be explored. Here we review the current progress in the development of mouse models for human HNSCC, with emphasis on conditional transgenic and knockout mouse models. These new models faithfully recapitulate human HNSCC at both the pathologic and molecular levels. These animal models will not only be useful to define the roles of specific genes in HNSCC development and progression but will also provide a unique tool for developing and testing new therapeutic approaches.

Prognostic impact ofHER-2/neu expression on squamous head and neck carcinomas

BACKGROUND

HER-2/neu gene amplification and protein overexpression have been identified in various solid tumors, but its prognostic relevance in head and neck squamous cell carcinoma (HNSCC) is still controversial.

METHODS

The study investigated the expression of HER-2/neu oncoprotein in HNSCC and sought possible correlations to various clinicopathologic parameters. Expression of HER-2/neu oncoprotein was assessed in archival tumor tissues from 87 untreated HNSCC patients by immunohistochemical technique. Data were correlated with both the clinicopathologic parameters and patient survival.

RESULTS

A high membranous HER-2/neu protein expression level was found in 39% of patients. Multivariate analysis indicated that HER-2/neu protein expression and pN lymph-node status were independent prognostic factors for disease-free survival.

CONCLUSIONS

HER2/neu overexpression and its relationship with survival suggest that new therapeutic approaches targeting epidermal growth factor receptor (EGFR) family receptors could provide a new way of treating HNSCC patients with HER2/neu-positive neoplastic lesions.

Enhanced tumour antiangiogenic effects when combining gefitinib with the antivascular agent ZD6126

Current experimental and clinical knowledge supports the optimisation of endothelial cell targeting using a strategy combining anti-EGFR drugs with antivascular agents. The purpose of the present study was to examine the effects of the association of ZD6126, an antivascular microtubule-destabilising agent, with gefitinib and irradiation on the growth of six head and neck human cancer cell lines xenografted in nude mice and to study predictive and molecular factors responsible for antitumour effects. CAL33- and Hep-2-grafted cell lines were the most sensitive to ZD6126 treatment, with VEGF levels significantly higher (P=0.0336) in these tumour xenografts compared to Detroit 562- and CAL27-grafted cell lines with relatively low VEGF levels that were not sensitive to ZD6126. In contrast, neither IL8 levels nor EGFR expression was linked to the antitumour effects of ZD6126. ZD6126 in combination with gefitinib resulted in a synergistic cytotoxic interaction with greater antitumour effects than gefitinib alone. The synergistic interaction between ZD6126 and gefitinib was corroborated by a significant decrease in CD31 labelling. The present study may serve for future innovative clinical applications, as it suggests that VEGF tumour levels are possible predictors for ZD6126 antitumour efficacy. It also supports the notion of antitumour supra-additivity when combining gefitinib and ZD6126, and identifies neoangiogenesis as the main determinant of this synergistic combination.

Epidermal growth factor receptor/angiogenesis dual targeting: preclinical experience

PURPOSE OF REVIEW

This review aims to critically examine the preclinical background regarding the combination of drugs targeting the epidermal growth factor receptor and anti-angiogenic compounds.

RECENT FINDINGS

There are studies exploring the anti-tumor efficacy of dual inhibitors, such as the compound ZD6474, which combines in the same molecule an anti-tyrosine kinase activity against the epidermal growth factor receptor and the vascular endothelial growth factor receptor. In addition, several studies have investigated the anti-tumor effects of combinations of an anti-epidermal growth factor receptor agent and a vascular endothelial growth factor receptor inhibitor. In general, in these studies, supra-additive anti-tumor efficacy was apparent when combining anti-epidermal growth factor receptor and anti-angiogenic treatments. Beneficial effects were also observed when combining this dual targeted therapy with either conventional chemotherapy or irradiation.

SUMMARY

Early clinical trials combining the anti-epidermal growth factor receptor drug erlotinib (Tarceva) and the anti-angiogenic agent bevacizumab (Avastin) show acceptable toxicity and promising anti-tumor activity (lung cancer), which need to be confirmed in randomized trials.

Expression of the epidermal growth factor receptor in conjunctival squamous cell carcinoma

PURPOSE

To determine whether the tyrosine kinase epidermal growth factor receptor (EGFR) is expressed in squamous cell carcinoma of the conjunctiva.

METHODS

A retrospective, observational case series of 5 patients with biopsy-proven conjunctival squamous cell carcinoma treated at one institution between January 1996 and April 2004. Medical records and tissue specimens from the 5 patients were reviewed. A control specimen of normal conjunctiva was also obtained from one of the 5 patients. Immunohistochemical analysis was performed using antibodies against EGFR.

RESULTS

Immunohistochemical staining showed that EGFR expression was moderate to strong in all tissue specimens, both in the normal mucosa and in the in situ and invasive components of the conjunctival squamous cell carcinomas.

CONCLUSIONS

An intense expression of EGFR occurs in squamous cell carcinoma of the conjunctiva. Further study is needed to determine whether an EGFR inhibitor that targets this expression would have potential therapeutic benefit in treating squamous cell carcinoma of the conjunctiva.

Mammalian Target of Rapamycin, a Molecular Target in Squamous Cell Carcinomas of the Head and Neck

Emerging knowledge on how the dysregulated function of signaling networks contributes to the malignant growth of squamous cell carcinoma of the head and neck (HNSCC) can now be exploited to identify novel mechanism-based anticancer treatments. In this regard, we have observed that persistent activation of the serine/threonine kinase Akt is a frequent event in HNSCC, and that blockade of its upstream kinase, 3'-phosphoinositide-dependent kinase 1, potently inhibits tumor cell growth. Akt promotes cell proliferation by its ability to coordinate mitogenic signaling with energy- and nutrient-sensing pathways that control protein synthesis through the atypical serine/threonine kinase, mammalian target of rapamycin (mTOR). This kinase, in turn, phosphorylates key eukaryotic translation regulators, including p70-S6 kinase and the eukaryotic translation initiation factor, 4E binding protein 1. Indeed, we show here that aberrant accumulation of the phosphorylated active form of S6, the most downstream target of the Akt-mTOR-p70-S6 kinase pathway, is a frequent event in clinical specimens from patients with HNSCC and their derived cell lines. Of interest, this enhanced level of the phosphorylated active form of S6 was rapidly reduced in HNSCC cell lines and HNSCC xenograft models at clinically relevant doses of rapamycin, which specifically inhibits mTOR. Furthermore, we observed that rapamycin displays a potent antitumor effect in vivo, as it inhibits DNA synthesis and induces the apoptotic death of HNSCC cells, ultimately resulting in tumor regression. These findings identify the Akt-mTOR pathway as a potential therapeutic target for HNSCC, and may provide the rationale for the early clinical evaluation of rapamycin and its analogues in patients with HNSCC.

Analysis of the dinucleotide repeat polymorphism in the epidermal growth factor receptor (EGFR) gene in head and neck cancer patients

BACKGROUND

Epidermal growth factor receptor (EGFR) overexpression is associated with poor prognosis in head and neck cancer. The first intron of EGFR gene is polymorphic (9-23 CA repeats) and transcription declines when the number of repeats increases.

PATIENTS AND METHODS

EGFR polymorphism (fluorescent genotyping) and expression (ligand-binding assay) were analyzed in tumors and normal tissues from 112 patients (100 men, 12 women; mean age 60 years).

RESULTS

The number of CA repeats varied from 15 to 22. Allelic distribution was trimodal (predominance of 16, 20 and 18 CA repeats). EGFR concentrations were significantly higher (P=0.02) in homozygous tumors as compared with heterozygous. Considering homozygous tumors, or classifying genotypes as short/long/intermediary (two alleles <17 versus two alleles > or =17 versus others), no relationship was observed between tumoral EGFR genotype and expression. In the 76 tumors exhibiting at least one 16-CA allele, the length of the remaining allele was inversely correlated to EGFR expression (P=0.047). Tumoral EGFR expression, performance status (WHO criteria) and node involvement were independent predictors of specific survival (P <0.01). Tumoral or normal tissue EGFR genotype did not influence survival.

CONCLUSIONS

Intron 1 EGFR polymorphism may be implicated in the regulation of EGFR expression in head and neck tumors.

Progression of head and neck squamous cell cancer

Squamous cell cancer in the head and neck region (HNSC) is unique concerning its progression since it remains locoregional for long time and visceral metastases develop only in a later stage of the disease. Accordingly, molecular markers of the local invasion and the lymphatic dissemination both have critical importance. HNSC progression is associated with deregulated control of cell proliferation and apoptosis but it seems equally significant the disregulation of the proteolytic machineries. Here we outline the lymphatic metastatic cascade for HNSC to depict key molecular determinants as possible prognostic factors or therapeutic targets identifying immunological selection as a major feature. Unlike in local spreading, invasive potential of cancer cells seems to be less significant during lymphatic dissemination due to the anatomical properties of the lymphatic vessels and tissues. There is a general believe that HNSC is one disease however, data indicate that the anatomical localization of the tumor (the "soil") such as oral, lingual, glottic or pharyngeal has a significant effect on the gene expression profile and corresponding biological behavior of HNSC. Furthermore, even the endocrine milieu of the host was proved to be influential in modulating the progression of HNSC. Gene expression profiling techniques combined with proteomics could help to define and select usefull genetic and biomarkers of progression of HNSC, some of them could well be potential novel therapeutic target.

Novel management of oral cancer: a paradigm of predictive oncology

The rationale for molecular-targeted prevention of oral cancer is strong. Oral cancer is a major global threat to public health with 300,000 new cases diagnosed worldwide on an annual basis. Notably, the great morbidity and mortality rates of this devastating disease have not improved in decades. Oral cancer development is a tobacco-related multistep and multifocal process involving field carcinogenesis and intraepithelial clonal spread. Biomarkers of genomic instability, such as aneuploidy and allelic imbalance, can accurately measure the cancer risk of oral premalignant lesions or intraepithelial neoplasia (IEN). Retinoid-oral IEN studies (e.g., retinoid acid receptor-beta, p53, genetic instability, loss of heterozygosity, and cyclin D1) have advanced the overall understanding of the biology of intraepithelial carcinogenesis and preventive agent molecular mechanisms and targets, important advances for monitoring preventive interventions, assessing cancer risk, and pharmacogenomics. Clinical management of oral IEN varies from watchful waiting to complete resection, although complete resection does not prevent oral cancer in high-risk patients. New approaches, such as interventions with molecular-targeted agents and agent combinations in molecularly defined high-risk oral IEN patients, are urgently needed to reduce the devastating worldwide consequences of oral cancer.

Tumor Cell and Endothelial Cell Therapy of Oral Cancer by Dual Tyrosine Kinase Receptor Blockade

Expression of the epidermal growth factor (EGF) and activation of its receptor (EGFR), a tyrosine kinase, are associated with progressive growth of head and neck cancer. Expression of the vascular endothelial growth factor (VEGF) is associated with angiogenesis and progressive growth of tumor. The tyrosine kinase inhibitor NVP-AEE788 (AEE788) blocks the EGF and VEGF signaling pathways. We examined the effects of AEE788 administered alone, or with paclitaxel (Taxol), on the progression of human head and neck cancer implanted orthotopically into nude mice. Cells of two different human oral cancer lines, JMAR and MDA1986, were injected into the tongues of nude mice. Mice with established tumors were randomized to receive three times per week oral AEE788, once weekly injected paclitaxel, AEE788 plus paclitaxel, or placebo. Oral tumors were resected at necropsy. Kinase activity, cell proliferation, apoptosis, and mean vessel density were determined by immunohistochemical immunofluorescent staining. AEE788 inhibited cell growth, induced apoptosis, and reduced the phosphorylation of EGFR, VEGFR-2, AKT, and mitogen-activated protein kinase in both cell lines. Mice treated with AEE788 and AEE788 plus paclitaxel had decreased microvessel density, decreased proliferative index, and increased apoptosis. Hence, AEE788 inhibited tumor vascularization and growth and prolonged survival. Inhibition of EGFR and VEGFR phosphorylation by AEE788 effectively inhibits cellular proliferation of squamous cell carcinoma of the head and neck, induces apoptosis of tumor endothelial cells and tumor cells, and is well tolerated in mice. These data recommend the consideration of patients with head and neck cancer for inclusion in clinical trials of AEE788.