EGFR-specific T cell frequencies correlate with EGFR expression in head and neck squamous cell carcinoma

Recent findings on the impact of ErbB receptors status on prognosis and therapy of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type, has often an aggressive course and is poorly responsive to current therapeutic approaches, so that 5-year survival rates for patients diagnosed with advanced disease is lower than 50%. The Epidermal Growth Factor Receptor (EGFR) has emerged as an established oncogene in HNSCC. Indeed, although HNSCCs are a heterogeneous group of cancers which differ for histological, molecular and clinical features, EGFR is overexpressed or mutated in a percentage of cases up to about 90%. Moreover, aberrant expression of the other members of the ErbB receptor family, ErbB2, ErbB3 and ErbB4, has also been reported in variable proportions of HNSCCs. Therefore, an increased expression/activity of one or multiple ErbB receptors is found in the vast majority of patients with HNSCC. While aberrant ErbB signaling has long been known to play a critical role in tumor growth, angiogenesis, invasion, metastatization and resistance to therapy, more recent evidence has revealed its impact on other features of cancer cells' biology, such as the ability to evade antitumor immunity. In this paper we will review recent findings on how ErbB receptors expression and activity, including that associated with non-canonical signaling mechanisms, impacts on prognosis and therapy of HNSCC.

A review of efficacy and safety of cetuximab and bevacizumab-based monoclonal antibodies in head and neck cancer

A combination of monoclonal antibodies prescribed along with the conventional standard of care has a potential to provide significant improvement in patients suffering from head and neck cancer. This combination has also shown a significant decrease in toxicities and improved overall quality of life. Cetuximab acts by inhibiting the human epidermal growth factors as its overexpression in head and neck tumours that are responsible for treatment failure, resistance, and metastasis. Whereas, bevacizumab acts by inhibiting the vascular endothelial growth factor since its overexpression leads to induction of tumour angiogenesis. Current research has not shown any remarkable beneficial effect in disease outcomes. Thus, the addition of these monoclonal antibodies to the standard regimen for head and neck cancer can be considered a prospect that might be beneficial. Cetuximab has already been included as an option under special recommendations in recurrent/metastatic head and neck cancer by NCCN in a platinum-based regimen as well as in combination with radiation therapy. This review outlines the applicability of cetuximab and bevacizumab in the treatment of head and neck cancer as well as the clinical trials performed that give an idea about the efficacy and safety of these monoclonal antibodies. Based upon the literature reviewed, it can be deduced that immunotherapy is to be adopted and different targets are to be explored in it in order to combat head and neck cancer. Currently, immunotherapeutic drugs of two major targets have been discussed. These agents are even effective in combination with other therapeutic modalities that are not being able to achieve desirable outcomes due to issues such as resistance and toxicities. Thus, newer targets as well as newer agents acting on established targets are to be explored in order to improve disease outcomes.

Human Leucocyte Antigens as Prognostic Markers in Head and Neck Squamous Cell Carcinoma

BACKGROUND

The induction and regulation of immune responses depend on human leucocyte antigen (HLA) molecules that present peptides derived from mutated neoantigens or tumor-associated antigens to cytotoxic T cells. The natural variation of HLA molecules might differ between tumor patients and the normal population. Thus, there might be associations between the frequencies of HLA alleles and the survival of tumor patients.

METHODS

This issue was studied in a cohort of 84 patients with head and neck squamous cell carcinomas (HNSCCs) of different localizations. The cohort was followed up for more than 10 years. HLA-A/B/C CTS-PCR-SSP typing at 1 field level from blood samples was performed, and the results were correlated with survival.

RESULTS

HLA-A*02 was the most prevalent allele in our cohort and was present in 51.1% of patients. The HLA-A*25 and HLA-C*06 alleles exhibited a significantly higher frequency in cancer patients than in the normal population of 174 blood and kidney donors (p = 0.02 and p = 0.01, respectively, Fisher's exact test). For HLA-C*04, a negative impact on overall survival in univariate analysis (p = 0.045) and a negative, but statistically insignificant effect on survival toward poorer survival in multivariate analysis (HR: 1.82; 95% CI: 0.99-3.34, p = 0.053) were observed. In addition, HLA-A*02 was also beneficial for overall survival and progression-free survival in multivariate analysis (HR 0.54; 95% CI: 0.31-0.92; p = 0.023).

CONCLUSION

HLA-A*02 allele expression might not only predict better survival but might also indicate superior tumor antigen presentation and, thus, help to select patients who could benefit from T-cell-dependent immunotherapies.

Prognostic Role of Combined EGFR and Tumor-Infiltrating Lymphocytes in Oral Squamous Cell Carcinoma

Background

Epidermal growth factor receptor (EGFR) is well known as a general prognostic biomarker for head and neck tumors, however the specific prognostic value of EGFR in oral squamous cell carcinoma (OSCC) is controversial. Recently, the presence of tumor-infiltrating T cells has been associated with significant survival advantages in a variety of disease sites. The present study will determine if the inclusion of T cell specific markers (CD3, CD4 and CD8) would enhance the prognostic value of EGFR in OSCCs.

Methods

Tissue microarrays containing 146 OSCC cases were analyzed for EGFR, CD3, CD4 and CD8 expression using immunohistochemical staining. EGFR and T cell expression scores were correlated with clinicopathological parameters and survival outcomes.

Results

Results showed that EGFR expression had no impact on overall survival (OS), but EGFR-positive (EGFR+) OSCC patients demonstrated significantly worse progression free survival (PFS) compared to EGFR-negative (EGFR-) patients. Patients with CD3, CD4 and CD8-positive tumors had significantly better OS compared to CD3, CD4 and CD8-negative patients respectively, but no impact on PFS. Combined EGFR+/CD3+ expression was associated with cases with no nodal involvement and significantly more favorable OS compared to EGFR+/CD3- expression. CD3 expression had no impact on OS or PFS in EGFR- patients. Combinations of EGFR/CD8 and EGFR/CD4 expression showed no significant differences in OS or PFS among the expression groups.

Conclusion

Altogether these results suggest that the expression of CD3+ tumor-infiltrating T cells can enhance the prognostic value of EGFR expression and warrants further investigation as prognostic biomarkers for OSCC.

Antitumor Peptide-Based Vaccine in the Limelight

The success of the immune checkpoint blockade has provided a proof of concept that immune cells are capable of attacking tumors in the clinic. However, clinical benefit is only observed in less than 20% of the patients due to the non-specific activation of immune cells by the immune checkpoint blockade. Developing tumor-specific immune responses is a challenging task that can be achieved by targeting tumor antigens to generate tumor-specific T-cell responses. The recent advancements in peptide-based immunotherapy have encouraged clinicians and patients who are struggling with cancer that is otherwise non-treatable with current therapeutics. By selecting appropriate epitopes from tumor antigens with suitable adjuvants, peptides can elicit robust antitumor responses in both mice and humans. Although recent experimental data and clinical trials suggest the potency of tumor reduction by peptide-based vaccines, earlier clinical trials based on the inadequate hypothesis have misled that peptide vaccines are not efficient in eliminating tumor cells. In this review, we highlighted the recent evidence that supports the rationale of peptide-based antitumor vaccines. We also discussed the strategies to select the optimal epitope for vaccines and the mechanism of how adjuvants increase the efficacy of this promising approach to treat cancer.

Trial watch: Peptide vaccines in cancer therapy

Prophylactic vaccination constitutes one of the most prominent medical achievements of history. This concept was first demonstrated by the pioneer work of Edward Jenner, dating back to the late 1790s, after which an array of preparations that confer life-long protective immunity against several infectious agents has been developed. The ensuing implementation of nation-wide vaccination programs has de facto abated the incidence of dreadful diseases including rabies, typhoid, cholera and many others. Among all, the most impressive result of vaccination campaigns is surely represented by the eradication of natural smallpox infection, which was definitively certified by the WHO in 1980. The idea of employing vaccines as anticancer interventions was first theorized in the 1890s by Paul Ehrlich and William Coley. However, it soon became clear that while vaccination could be efficiently employed as a preventive measure against infectious agents, anticancer vaccines would have to (1) operate as therapeutic, rather than preventive, interventions (at least in the vast majority of settings), and (2) circumvent the fact that tumor cells often fail to elicit immune responses. During the past 30 y, along with the recognition that the immune system is not irresponsive to tumors (as it was initially thought) and that malignant cells express tumor-associated antigens whereby they can be discriminated from normal cells, considerable efforts have been dedicated to the development of anticancer vaccines. Some of these approaches, encompassing cell-based, DNA-based and purified component-based preparations, have already been shown to exert conspicuous anticancer effects in cohorts of patients affected by both hematological and solid malignancies. In this Trial Watch, we will summarize the results of recent clinical trials that have evaluated/are evaluating purified peptides or full-length proteins as therapeutic interventions against cancer.

OX40+ plasmacytoid dendritic cells in the tumor microenvironment promote antitumor immunity

Plasmacytoid DCs (pDCs), the major producers of type I interferon, are principally recognized as key mediators of antiviral immunity. However, their role in tumor immunity is less clear. Depending on the context, pDCs can promote or suppress antitumor immune responses. In this study, we identified a naturally occurring pDC subset expressing high levels of OX40 (OX40+ pDC) enriched in the tumor microenvironment (TME) of head and neck squamous cell carcinoma. OX40+ pDCs were distinguished by a distinct immunostimulatory phenotype, cytolytic function, and ability to synergize with conventional DCs (cDCs) in generating potent tumor antigen-specific CD8+ T cell responses. Transcriptomically, we found that they selectively utilized EIF2 signaling and oxidative phosphorylation pathways. Moreover, depletion of pDCs in the murine OX40+ pDC-rich tumor model accelerated tumor growth. Collectively, we present evidence of a pDC subset in the TME that favors antitumor immunity.

Immune Responses to Epidermal Growth Factor Receptor (EGFR) and Their Application for Cancer Treatment

Epidermal growth factor receptor (EGFR) is a prototypic cell-surface receptor belonging to the ErbB/HER onocogene family. Overexpression or somatic mutations of EGFR have been reported to play an important role in tumorigenesis in various types of epithelial cancers. Therefore, targeting of EGFR with specific blocking antibodies or inhibitors have been developing for treatment for EGFR-associated tumors. Immune responses to HER2, another molecule of the ErbB/HER onocogene family, have been well studied, but only limited information on the immune responses to EGFR in cancer has been currently available. In this review, we have summarized the available data and discussed potential clinical importance of the anti-EGFR immune responses and EGFR-mediated immune regulation in cancer. Several lines of evidence suggest that cellular and humoral immune responses to EGFR might be useful as a marker and/or target for cancer therapy against EGFR-associated tumors. In addition, recent studies suggest the critical roles of EGFR-mediated signaling in regulation of expression of an immune checkpoint molecule, programmed death-ligand 1 (PD-L1) in tumor cells. Further studies are warranted to clarify the impact of the anti-EGFR immune responses and EGFR-mediated immunomodulation for clinical application for cancer treatment.

CD137 Stimulation Enhances Cetuximab-Induced Natural Killer: Dendritic Cell Priming of Antitumor T-Cell Immunity in Patients with Head and Neck Cancer

PURPOSE

Cetuximab, an EGFR-specific antibody (mAb), modestly improves clinical outcome in patients with head and neck cancer (HNC). Cetuximab mediates natural killer (NK) cell:dendritic cell (DC) cross-talk by cross-linking FcγRIIIa, which is important for inducing antitumor cellular immunity. Cetuximab-activated NK cells upregulate the costimulatory receptor CD137 (4-1BB), which, when triggered by agonistic mAb urelumab, might enhance NK-cell functions, to promote T-cell-based immunity.

EXPERIMENTAL DESIGN

CD137 expression on tumor-infiltrating lymphocytes was evaluated in a prospective cetuximab neoadjuvant trial, and CD137 stimulation was evaluated in a phase Ib trial, in combining agonistic urelumab with cetuximab. Flow cytometry and cytokine release assays using NK cells and DC were used in vitro, testing the addition of urelumab to cetuximab-activated NK, DC, and cross presentation to T cells.

RESULTS

CD137 agonist mAb urelumab enhanced cetuximab-activated NK-cell survival, DC maturation, and tumor antigen cross-presentation. Urelumab boosted DC maturation markers, CD86 and HLA DR, and antigen-processing machinery (APM) components TAP1/2, leading to increased tumor antigen cross-presentation. In neoadjuvant cetuximab-treated patients with HNC, upregulation of CD137 by intratumoral, cetuximab-activated NK cells correlated with FcγRIIIa V/F polymorphism and predicted clinical response. Moreover, immune biomarker modulation was observed in an open label, phase Ib clinical trial, of patients with HNC treated with cetuximab plus urelumab.

CONCLUSIONS

These results suggest a beneficial effect of combination immunotherapy using cetuximab and CD137 agonist in HNC. Clin Cancer Res; 23(3); 707-16. ©2016 AACR.

Targeting HER-3 to elicit antitumor helper T cells against head and neck squamous cell carcinoma

HER-3 expression has been reported to act as an important oncoprotein in head and neck squamous cell carcinoma. This protein is known to control tumor proliferation and acquisition of resistance by tumor cells towards EGFR inhibitors, therefore, development of a HER-3-targeted therapy is desirable. In this study, we found that HER-3 expression on tumor cells was increased after EGFR inhibition. To establish a novel therapeutic approach for HER-3-positive head and neck carcinoma, we identified a HER-3 helper epitope that could elicit effective helper T cell responses to the naturally processed HER-3-derived epitope presented in a HER-3 expressing tumors. This epitope induced potent cytolytic activity of CD4 T cells against such tumor cells. Moreover, pan HER-family tyrosine kinase inhibitor augmented the responses of HER-3-reactive CD4 T cells via upregulation of HLA-DR protein on the surface of tumor cells. Our results supports the validity of CD4 T cell-dependent HER-3-targeted therapy combined with a broad inhibitor of HER-family.

The immune system and head and neck squamous cell carcinoma: from carcinogenesis to new therapeutic opportunities

Head and neck squamous cell carcinomas (HNSCCs) exhibit complex interactions with the host immune system that may simultaneously explain resistance to various therapeutic modalities and that may also provide opportunities for therapeutic intervention. Discoveries in immunologic research over the last decade have led to an increased understanding of these interactions as well as the development of a multitude of investigational immunotherapies. Here, we describe the interaction between HNSCC and the immune system, including a discussion of immune cells involved with tumor carcinogenesis and the role of immune-modulating factors derived from tumors. We also describe the current immunotherapeutic approaches being investigated for HNSCC, including a discussion of the successes and limitations. With this review, we hope to present HNSCC as a model to guide future research in cancer immunology.

Targeting CD137 enhances the efficacy of cetuximab

Treatment with cetuximab, an EGFR-targeting IgG1 mAb, results in beneficial, yet limited, clinical improvement for patients with head and neck (HN) cancer as well as colorectal cancer (CRC) patients with WT KRAS tumors. Antibody-dependent cell-mediated cytotoxicity (ADCC) by NK cells contributes to the efficacy of cetuximab. The costimulatory molecule CD137 (4-1BB) is expressed following NK and memory T cell activation. We found that isolated human NK cells substantially increased expression of CD137 when exposed to cetuximab-coated, EGFR-expressing HN and CRC cell lines. Furthermore, activation of CD137 with an agonistic mAb enhanced NK cell degranulation and cytotoxicity. In multiple murine xenograft models, including EGFR-expressing cancer cells, HN cells, and KRAS-WT and KRAS-mutant CRC, combined cetuximab and anti-CD137 mAb administration was synergistic and led to complete tumor resolution and prolonged survival, which was dependent on the presence of NK cells. In patients receiving cetuximab, the level of CD137 on circulating and intratumoral NK cells was dependent on postcetuximab time and host FcyRIIIa polymorphism. Interestingly, the increase in CD137-expressing NK cells directly correlated to an increase in EGFR-specific CD8+ T cells. These results support development of a sequential antibody approach against EGFR-expressing malignancies that first targets the tumor and then the host immune system.

Integrating novel therapeutic monoclonal antibodies into the management of head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is an immunosuppressive malignancy. Interest in developing novel immunotherapies in HNSCC has been reawakened by the success of cetuximab, a therapeutic monoclonal antibody (mAb) against the epidermal growth factor receptor, which likely relies on immune as well as antisignaling mechanisms. This review focuses on novel therapeutic mAbs in current clinical development against established mechanisms of immune evasion in HNSCC, targeting: 1) tumor antigens, with resultant potential to induce antibody-dependent cell-mediated cytotoxicity and T cell activation; 2) immunosuppressive cytokines; 3) costimulatory tumor necrosis factor-family receptors; and 4) coinhibitory immune checkpoint receptors. Clinical trials of immunotherapeutic mAbs as monotherapy, in combination with cytolytic standard therapies exposing tumor antigens or in combination with other immunomodulatory mAbs, are urgently needed in HNSCC.

Promising systemic immunotherapies in head and neck squamous cell carcinoma

Patients with head and neck squamous cell carcinoma (HNSCC) demonstrate poor survival and significant treatment morbidity with standard therapy. The immune profile in HNSCC, whether caused by carcinogen exposure or human papillomavirus (HPV), is notably immunosuppressive. Early clinical trials of immunotherapy in HNSCC were troubled by systemic toxicity or difficulties in local administration. Now, interest in immunotherapy has been revitalized by mechanistic insights into immune evasion by HNSCC, coupled to ongoing development of novel immunotherapies. This review will summarize immune escape mechanisms in HNSCC, namely downregulation of tumor antigen (TA) presentation, aberrant regulation of the signal transducer and activator of transcription (STAT) family, the immunosuppressive cytokine milieu, and dysregulation of immune effector cells. Therapeutic strategies hypothesized to specifically counter HNSCC immunosuppression will then be discussed. We will survey TA- targeted monoclonal antibodies (mAb), including the prototype cetuximab, as well as adjunctive strategies to enhance antibody-dependent cell-mediated cytotoxicity. We will review immunomodulation to restore STAT1/STAT3 activation balance. Examples of mAb therapy to block immunosuppressive cytokines, such as interleukin-6 or VEGF, will be provided. mAbs which release co-inhibitory T cell receptors such as CTLA-4 and PD-1, overexpressed in HNSCC, also hold therapeutic promise. Finally, we will describe principles for therapeutic vaccination in HPV-associated HNSCC, where non-host TAs such as viral oncoproteins represent ideal targets, and HPV-negative HNSCC, where p53 is a promising target. Insights into immunosuppression in HNSCC have elucidated mechanistic targets for immunotherapy. Rational clinical investigation may lead to effective stand alone or combinatorial treatment approaches.

Cetuximab-activated natural killer and dendritic cells collaborate to trigger tumor antigen-specific T-cell immunity in head and neck cancer patients

PURPOSE

Tumor antigen-specific monoclonal antibodies (mAb) block oncogenic signaling and induce Fcγ receptor (FcγR)-mediated cytotoxicity. However, the role of CD8(+) CTL and FcγR in initiating innate and adaptive immune responses in mAb-treated human patients with cancer is still emerging.

EXPERIMENTAL DESIGN

FcγRIIIa codon 158 polymorphism was correlated with survival in 107 cetuximab-treated patients with head and neck cancer (HNC). Flow cytometry was carried out to quantify EGF receptor (EGFR)-specific T cells in cetuximab-treated patients with HNC. The effect of cetuximab on natural killer (NK) cell, dendritic cell (DC), and T-cell activation was measured using IFN-γ release assays and flow cytometry.

RESULTS

FcγRIIIa polymorphism did not predict clinical outcome in cetuximab-treated patients with HNC; however, elevated circulating EGFR(853-861)-specific CD8(+) T cells were found in cetuximab-treated patients with HNC (P < 0.005). Cetuximab promoted EGFR-specific cellular immunity through the interaction of EGFR(+) tumor cells and FcγRIIIa on NK cells but not on the polymorphism per se. Cetuximab-activated NK cells induced IFN-γ-dependent expression of DC maturation markers, antigen processing machinery components such as TAP-1/2 and T-helper cell (T(H)1) chemokines through NKG2D/MICA binding. Cetuximab initiated adaptive immune responses via NK cell-induced DC maturation, which enhanced cross-presentation to CTL specific for EGFR as well as another tumor antigen, MAGE-3.

CONCLUSION

Cetuximab-activated NK cells promote DC maturation and CD8(+) T-cell priming, leading to tumor antigen spreading and TH1 cytokine release through "NK-DC cross-talk." FcγRIIIa polymorphism did not predict clinical response to cetuximab but was necessary for NK-DC interaction and mAb-induced cross-presentation. EGFR-specific T cells in cetuximab-treated patients with HNC may contribute to clinical response.

[Immunotherapy of head and neck cancer. Current developments]

In order to improve the prognosis for patients with head and neck squamous cell cancer (HNSCC) the introduction of new therapeutic strategies is necessary. The concept of immunotherapy has been applied and improved for several years and recent studies have used tumor-specific antigens which facilitates targeted oncologic therapy. However, immunotherapy is hampered by the fact that immunosuppressive mechanisms are pronounced and relevant effector cells are suppressed, especially in patients with HNSCC. Successful immunotherapy could induce an antitumor immune response by restitution of these cell populations. Current anti-tumor immunotherapy includes unspecific immune stimulation, genetic modification of tumor and immune cells, the use of monoclonal antibodies, e.g. cetuximab, adoptive cell transfer and tumor vaccination. In the future, these biologic therapies alone or in combination with conventional therapeutic regimens could present a valuable therapeutic option for HNSCC patients.

Epigallocatechin gallate sensitizes CAL-27 human oral squamous cell carcinoma cells to the anti-metastatic effects of gefitinib (Iressa) via synergistic suppression of epidermal growth factor receptor and matrix metalloproteinase-2

Human head and neck squamous cell carcinoma (HNSCC) is a major cause of cancer-related death during the last decade due to its related metastasis and poor treatment outcomes. Gefitinib (Iressa), a tyrosine kinase inhibitor has been reported to reduce the metastatic abilities of oral cancer. Previous studies have shown that epigallocatechin gallate (EGCG), a green tea polyphenol, possesses cancer chemopreventive and anticancer activity. However, the mechanisms involved in the suppression of invasion and metastasis of human oral cancer cells following co-incubation with gefitinib and EGCG remain poorly understood. In the present study, we attempted to investigate the synergistic effects of a combined treatment of gefitinib and EGCG in CAL-27 cells in vitro and to elucidate the underlying molecular mechanisms associated with the supression of cell migration and invasion. In the present study, we found that the individual treatments or the combined treatment of gefitinib and EGCG synergistically inhibited the invasion and migration of CAL-27 cells using Transwell invasion and wound-healing scratch assays, respectively. Similarly, gefitinib in combination with EGCG synergistically attenuated enzymatic activity and the protein expression of MMP-2 in CAL-27 cells. Furthermore, individual or combined treatment with EGCG and gefitinib suppressed the protein expression of p-EGFR and the phosphorylated protein levels of ERK, JNK, p38 and AKT and displayed inhibitory effects on metastatic ability of CAL-27 cells. Combined effects of EGCG and gefitinib-altered anti-metastatic actions for related gene expression were observed using DNA microarray analysis. Importantly, EGCG sensitizes CAL-27 cells to gefitinib-suppressed phosphorylation of epidermal growth factor receptor (EGFR in vitro. Taken together, our results suggest that the synergistic suppression of the metastatic ability of CAL-27 cells after EGCG and gefitinib individual or combined treatment are mediated through mitogen-activated protein kinase (MAPK) signaling. Our novel findings provide potential insights into the mechanism involved with synergistic responses of gefitinib and EGCG against the progression of oral cancer.