Sandra P. Gibson

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 EGFR853–861–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 (TH1) 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. Clin Cancer Res; 19(7); 1858–72. ©2013 AACR.

CD137 stimulation enhances cetuximab induced natural killer (NK): dendritic cell (DC) priming of anti-tumor T cell immunity in head and neck cancer patients

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.

Immune biomarkers of anti-EGFR monoclonal antibody therapy

The tumor antigen (TA)-targeted monoclonal antibodies (mAb) cetuximab and panitumumab target the human epidermal growth factor receptor and have been integrated into treatment regimens for advanced squamous cell carcinoma of the head and neck (SCCHN). The therapeutic efficacy of these mAbs has been found to be enhanced when combined with radiotherapy and chemotherapy. However, clinical trials indicate that these findings are limited to fewer than 20% of treated patients. Therefore, identifying patients who are likely to benefit from these agents is crucial to improving therapeutic strategies. Interestingly, it has been noted that TA-targeted mAbs mediate their effects by contributing to cell-mediated cytotoxicity in addition to inhibition of downstream signaling pathways. Here, we describe the potential immunogenic mechanisms underlying these clinical findings, their role in the varied clinical response and identify the putative biomarkers of antitumor activity. We review potential immunological biomarkers that affect mAb therapy in SCCHN patients, the implications of these findings and how they translate to the clinical scenario, which are critical to improving patient selection and ultimately outcomes for patients undergoing therapy.The tumor antigen (TA)-targeted monoclonal antibodies (mAb) cetuximab and panitumumab target the human epidermal growth factor receptor and have been integrated into treatment regimens for advanced squamous cell carcinoma of the head and neck (SCCHN). The therapeutic efficacy of these mAbs has been found to be enhanced when combined with radiotherapy and chemotherapy. However, clinical trials indicate that these findings are limited to fewer than 20% of treated patients. Therefore, identifying patients who are likely to benefit from these agents is crucial to improving therapeutic strategies. Interestingly, it has been noted that TA-targeted mAbs mediate their effects by contributing to cell-mediated cytotoxicity in addition to inhibition of downstream signaling pathways. Here, we describe the potential immunogenic mechanisms underlying these clinical findings, their role in the varied clinical response and identify the putative biomarkers of antitumor activity. We review potential immunological biomarkers that affect mAb therapy in SCCHN patients, the implications of these findings and how they translate to the clinical scenario, which are critical to improving patient selection and ultimately outcomes for patients undergoing therapy.

Characterization of human papillomavirus antibodies in individuals with head and neck cancer

BACKGROUND Human papillomavirus type 16 (HPV16) E6 antibodies are a promising biomarker of oropharyngeal cancer (OPC); however, seropositivity among non-OPC cases is not well characterized. METHODS Pre-treatment sera from 260 (38 OPC, 222 non-OPC) incident head and neck cancers diagnosed at the University of Pittsburgh between 2003 and 2006 were tested for HPV16 (L1,E1,E2,E4,E6,E7) and non-HPV16 E6 (HPV6,11,18,33) antibodies. Sensitivity and specificity of HPV16 E6 antibodies for HPV-driven tumors was evaluated among tumors with known HPV status (n=25). RESULTS 63.2% of OPC versus 27.5% of non-OPC cases were HPV16 seropositive; HPV16 E6 seroprevalence was 60.5% and 6.3% respectively, odds ratio 22.8 (95% confidence interval [CI] 9.8-53.1). Sensitivity and specificity of HPV16 E6 antibodies for HPV-driven OPC was 100% [95% CI: 50-100%; n=6] and 100% [95% CI: 60-100%, n=4] compared to 0% (n=2) and 0% (n=13) for non-OPC cases. CONCLUSIONS HPV16 antibodies were significantly more common in OPC versus non-OPC cases, particularly HPV16 E6 antibodies.

MicroRNA-363 targets myosin 1B to reduce cellular migration in head and neck cancer

BackgroundSquamous cell carcinoma of the head and neck (SCCHN) remains a prevalent and devastating disease. Recently, there has been an increase in SCCHN cases that are associated with high-risk human papillomavirus (HPV) infection. The clinical characteristics of HPV-positive and HPV-negative SCCHN are known to be different but their molecular features are only recently beginning to emerge. MicroRNAs (miRNAs, miRs) are small, non-coding RNAs that are likely to play significant roles in cancer initiation and progression where they may act as oncogenes or tumor suppressors. Previous studies in our laboratory showed that miR-363 is overexpressed in HPV-positive compared to HPV-negative SCCHN cell lines, and the HPV type 16-E6 oncoprotein upregulates miR-363 in SCCHN cell lines. However, the functional role of miR-363 in SCCHN in the context of HPV infection remains to be elucidated.MethodsWe analyzed miR-363 levels in SCCHN tumors with known HPV-status from The Cancer Genome Atlas (TCGA) and an independent cohort from our institution. Cell migration studies were conducted following the overexpression of miR-363 in HPV-negative cell lines. Bioinformatic tools and a luciferase reporter assay were utilized to confirm that miR-363 targets the 3’-UTR of myosin 1B (MYO1B). MYO1B mRNA and protein expression levels were evaluated following miR-363 overexpression in HPV-negative SCCHN cell lines. Small interfering RNA (siRNA) knockdown of MYO1B was performed to assess the phenotypic implication of reduced MYO1B expression in SCCHN cell lines.ResultsMiR-363 was found to be overexpressed in HPV-16-positive compared to the HPV-negative SCCHN tumors. Luciferase reporter assays performed in HPV-negative JHU028 cells confirmed that miR-363 targets one of its two potential binding sites in the 3’UTR of MYO1B. MYO1B mRNA and protein levels were reduced upon miR-363 overexpression in four HPV-negative SCCHN cell lines. Increased miR-363 expression or siRNA knockdown of MYO1B expression reduced Transwell migration of SCCHN cell lines, indicating that the miR-363-induced migration attenuation of SCCHN cells may act through MYO1B downregulation.ConclusionsThese findings demonstrate that the overexpression of miR-363 reduces cellular migration in head and neck cancer and reveal the biological relationship between miR-363, myosin 1b, and HPV-positive SCCHN.

Human papillomavirus 16 E6 antibodies are sensitive for human papillomavirus–driven oropharyngeal cancer and are associated with recurrence

Human papillomavirus 16 (HPV16) E6 antibodies may be an early marker of the diagnosis and recurrence of human papillomavirus–driven oropharyngeal cancer (HPV‐OPC).

A Phase Ib Study of Immune Biomarker Modulation with Neoadjuvant Cetuximab and TLR8 stimulation in Head and Neck Cancer to Overcome Suppressive Myeloid Signals.

Purpose: The response rate of patients with head and neck squamous cell carcinoma (HNSCC) to cetuximab therapy is only 15% to 20%, despite frequent EGFR overexpression. Because immunosuppression is common in HNSCC, we hypothesized that adding a proinflammatory TLR8 agonist to cetuximab therapy might result in enhanced T-lymphocyte stimulation and anti–EGFR-specific priming. Experimental Design: Fourteen patients with previously untreated HNSCC were enrolled in this neoadjuvant trial and treated preoperatively with 3 to 4 weekly doses of motolimod (2.5 mg/m2) and cetuximab. Correlative tumor and peripheral blood specimens were obtained at baseline and at the time of surgical resection and analyzed for immune biomarker changes. Preclinical in vitro studies were also performed to assess the effect of cetuximab plus motolimod on myeloid cells. Results: TLR8 stimulation skewed monocytes toward an M1 phenotype and reversed myeloid-derived suppressor cell (MDSC) suppression of T-cell proliferation in vitro. These data were validated in a prospective phase Ib neoadjuvant trial, in which fewer MDSC and increased M1 monocyte infiltration were found in tumor-infiltrating lymphocytes. Motolimod plus cetuximab also decreased induction of Treg and reduced markers of suppression, including CTLA-4, CD73, and membrane-bound TGFβ. Significantly increased circulating EGFR-specific T cells were observed, concomitant with enhanced CD8+ T-cell infiltration into tumors. These T cells manifested increased T-cell receptor (TCR) clonality, upregulation of the costimulatory receptor CD27, and downregulation of inhibitory receptor TIGIT. Conclusions: Enhanced inflammatory stimulation in the tumor microenvironment using a TLR agonist overcomes suppressive myeloid and regulatory cells, enhancing the cellular antitumor immune response by therapeutic mAb in HNSCC. Clin Cancer Res; 24(1); 62–72. ©2017 AACR.

STING activation enhances cetuximab-mediated NK cell activation and DC maturation and correlates with HPV+ status in head and neck cancer

OBJECTIVES The intracellular DNA sensor stimulator of interferon genes (STING) has recently been shown to play a vital role in anti-viral and anti-tumor immune responses stimulating cytokine production. While human papillomavirus (HPV) is a causative agent for a subset of head and neck squamous cell carcinoma (HNSCC) with unique etiology and clinical outcome, how the STING pathway is regulated in a virus-induced tumor microenvironment is not well understood. Since STING inactivation likely reflects immunoescape via innate immunity, we hypothesized that its restoration would improve efficacy of the immune modulatory monoclonal antibody (mAb), cetuximab. MATERIALS AND METHODS We correlated STING protein expression with clinical parameters by immunohistochemistry (n = 106) and its mRNA expression from The Cancer Genome Atlas (TCGA) in HNSCC tissue specimens. STING protein expression was tested for association with cancer-specific survival (CSS). We further examined the impact of STING activation on cetuximab-mediated immunity using an in vitro NK:DC:tumor cells co-culture system. RESULTS In this study, we found that expression of STING both at the protein and mRNA level was higher in HPV positive (HPV+) specimens but unrelated to TNM stage or cancer-specific survival. Our in vitro studies verified that STING activation enhanced cetuximab mediated NK cell activation and DC maturation. CONCLUSION Our findings suggest a novel role of STING in HPV-related carcinogenesis, in which activation of the STING signaling pathway may facilitate anti-tumor response in HNSCC patients, particularly in combination with therapeutic monoclonal antibodies (mAbs) such as cetuximab, an epidermal growth factor receptor (EGFR) inhibitor.

T cell receptor richness in peripheral blood increases after cetuximab therapy and correlates with therapeutic response

ABSTRACT The role of T cell receptor (TCR) signaling for adaptive immune responses is essential. The ability to respond to a broad spectrum of tumor antigens requires an adaptive selection of various TCR. So far, little is known about the role of TCR richness and clonality in the cellular immune response to head and neck cancer (HNC), though the Endothelial Growth Factor Receptor (EGFR)-specific CD8+ T cell response can be enhanced by cetuximab therapy. Therefore, we investigated differences in TCR sequences between human papillomavirus (HPV)+ and HPV− HNC patients, as well as differences in TCR sequence characteristics between T cells of peripheral blood mononuclear cells (PBMC) and tumor infiltrating lymphocytes (TIL). Additionally, we were able to investigate the TCR richness and clonality in samples pre- and post- treatment in a prospective clinical trial of neoadjuvant cetuximab. Interestingly, HPV+ and HPV− HNSCC did not significantly differ in the extent of TCR clonality and richness in PBMC or TIL. However, neoadjuvant cetuximab treatment increased the number of unique TCR sequences in PBMC (p = 0.0003), which was more prominent in the clinical responder patients compared to non-responders (p = 0.04). A trend toward TCR gene focusing was observed in TIL (p = 0.1) post-treatment. Thus, an increase in richness of TCR sequences in the periphery with a focusing at the tumor site is associated with an improved treatment response, suggesting an influence of peripheral quantity and intratumoral quality on adaptive immunity in cetuximab treated patients.

Anti-EGFR mAb cetuximab therapy increases T cell receptor (TCR) diversity in the peripheral blood and focuses TCR richness in the tumor microenvironment

T cell receptor (TCR) recognition of tumor antigen is essential for effective antitumor immunity. The immune system`s ability to respond to a broad spectrum of antigens requires a sophisticated selection of various TCR. So far, little is known about the role of TCR richness and clonality in the immune response to the EGFR-specific mAb, cetuximab. Therefore, we investigated differences in TCR sequences between HPV+ and HPV- patients, as well as differences in sequence characteristics between T cells of peripheral blood mononuclear cells (PBMC) and tumor infiltrating lymphocytes (TIL). Additionally, we were able to investigate the TCR richness and clonality in samples pre- and post-treatment in a clinical single agent cetuximab trial.