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    <div>AbstractPurpose:<p>mAbs including cetuximab can induce antibody-dependent cellular cytotoxicity (ADCC) and cytokine production mediated via innate immune cells with the ability to recognize mAb-coated tumors. Preclinical modeling has shown that costimulation of natural killer (NK) cells via the Fc receptor and the IL12 receptor promotes NK-cell–mediated ADCC and production of cytokines.</p>Patients and Methods:<p>This phase I/II trial evaluated the combination of cetuximab with IL12 for the treatment of EGFR-expressing head and neck cancer. Treatment consisted of cetuximab 500 mg/m<sup>2</sup> i.v. every 2 weeks with either 0.2 mcg/kg or 0.3 mcg/kg IL12 s.c. on days 2 and 5 of the 2-week cycle, beginning with cycle 2. Correlative studies from blood draws obtained prior to treatment and during therapy included measurement of ADCC, serum cytokine, and chemokine analysis, determination of NK cell FcγRIIIa polymorphisms, and an analysis of myeloid-derived suppressor cell (MDSC) frequency in peripheral blood.</p>Results:<p>The combination of cetuximab and IL12 was well tolerated. No clinical responses were observed, however, 48% of patients exhibited prolonged progression-free survival (PFS; average of 6.5 months). Compared with patients that did not exhibit clinical benefit, patients with PFS >100 days exhibited increased ADCC as therapy continued compared with baseline, greater production of IFNγ, IP-10, and TNFα at the beginning of cycle 8 compared with baseline values and had a predominance of monocytic MDSCs versus granulocytic MDSCs prior to therapy.</p>Conclusions:<p>Further investigation of IL12 as an immunomodulatory agent in combination with cetuximab in head and neck squamous cell carcinoma is warranted.</p></div>
    Abstract Head and neck squamous cell carcinoma (HNSCC), the sixth most common cancer worldwide, has a five-year survival rate of only 50%. The first targeted agent FDA approved for treatment of HNSCC was cetuximab, a monoclonal antibody targeting the epidermal growth factor receptor (EGFR). Despite EGFR overexpression in up to 90% of HNSCC tumors and ample evidence supporting EGFR as a therapeutic target in HNSCC, the response rate for single-agent cetuximab is below 20%, and resistance to cetuximab-containing therapy remains a major obstacle in the effective treatment of HNSCC. Identification and targeting of mediators of cetuximab resistance is needed to improve patient outcomes. Secretion of the cytokine interleukin 6 (IL-6) has been proposed as a mechanism of resistance to cetuximab in HNSCC, and inhibition of signal transducer and activator of transcription 3 (STAT3), a downstream mediator of IL-6 signaling, has been shown to overcome cetuximab resistance in preclinical HNSCC models. Thus, we hypothesize that IL-6 signaling mediates resistance to cetuximab and that co-treatment with agents targeting the IL-6 pathway will enhance the therapeutic efficacy of cetuximab in HNSCC. We have generated cetuximab-resistant variants of the cetuximab-sensitive HNSCC cell lines Cal33 and PE/CA-PJ49. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis indicated that IL6 expression is increased 3.5- to 8-fold in cetuximab-resistant variants compared to the parental cells from which they were derived. In addition, a colony formation assay revealed that, as expected, cetuximab-treated parental cells formed fewer colonies than vehicle-treated cells, while cetuximab treatment had no effect on the ability of cetuximab-resistant PE/CA-PJ49 variants to form colonies. In contrast, treatment with tocilizumab, an IL-6 receptor-neutralizing monoclonal antibody, markedly reduced the colony-forming ability of the cetuximab-resistant variants, but not parental cells. These results suggest that targeted inhibition of IL-6 signaling may effectively inhibit proliferation in cetuximab-refractory HNSCC cells. Citation Format: Rachel A. O'Keefe, Neil Bhola, Toni M. Brand, Yan Zeng, Daniel E. Johnson, Jennifer R. Grandis. Targeting IL-6 signaling overcomes cetuximab resistance in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4108. doi:10.1158/1538-7445.AM2017-4108
    The aims of this study were to validate in vitro drug sensitivity testing of head and neck squamous cell carcinoma (HNSCC) cell lines in an in vivo xenograft model and to identify treatment-induced changes in the epidermal growth factor receptor (EGFR) signaling pathway that could be used as markers for cetuximab treatment response.The in vitro and in vivo cetuximab sensitivity of two HNSCC cell lines, UT-SCC-14 and UT-SCC-45, was assessed using a crystal violet assay and xenografts in nude mice, respectively. The expression of EGFR, phosphorylated EGFR (pEGFR), phosphorylated Src (pSrc), and Ki-67 was investigated by immunohistochemistry. To verify these results, the in vitro expression of EGFR and pEGFR was analyzed with ELISA in a panel of 10 HNSCC cell lines.A close correlation was found between in vitro and in vivo cetuximab sensitivity data in the two investigated HNSCC cell lines. In treatment sensitive UT-SCC-14 xenografts, there was a decrease in EGFR, pEGFR, and pSrc upon cetuximab treatment. Interestingly, in insensitive UT-SCC-45 xenografts, an increased expression of these three proteins was found. The change in EGFR and pEGFR expression in vivo was confirmed in cetuximab-sensitive and cetuximab-insensitive HNSCC cell lines using ELISA.High sensitivity to cetuximab was strongly associated with a treatment-induced reduction in pEGFR both in vivo and in vitro in a panel of HNSCC cell lines, suggesting that EGFR and pEGFR dynamics could be used as a predictive biomarker for cetuximab treatment response.
    EGFR Inhibitors
    Citations (7)
    Abstract Introduction Cetuximab is a IgG1 monoclonal antibody against epidermal growth factor receptor (EGFR) used for head and neck squamous cell carcinoma (HNSCC) treatment. In addition to EGFR targeting, cetuximab is able to develop an antibody-dependent cell-mediated cytotoxicity (ADCC), triggered by Fc receptors (Fcγ-R) on Natural Killer cells, macrophages and polymorphonucleated leukocytes. This prospective study examined the possible prognostic value of cetuximab-mediated ADCC response in a cohort of HNSCC patients. Patients and Methods There were 63 patients treated with curative intent with chemo-radiotherapy (CT-RT), associated (N = 39) or not (N = 24) with cetuximab. Peripheral blood samples were collected at start of therapy. Intrinsic ADCC was evaluated from ex vivo NK-dependent activity measuring LDH release through the Cytotox 96® non radioactive cytotoxicity assay, previously standardized in our laboratory (Crit Rev Oncol Hematol, 2015). EGFR tumoral expression was analyzed by immunohistochemistry. Results Median ADCC response at treatment start for all patients was 56.1% (range 5-99%). Analysing the whole population, patients with ADCC above the median value (high) showed a better OS as compared to patients with ADCC below the median (low), HR = 0.3827 (95% CI, 0.1464 to 1.000), p = 0.05 (Long-rank Mantel-Cox Test). A sub-group analysis confirmed a possible link between high ADCC and a better OS (CT-RT group, p = 0.223 and CT-RT+cetuximab group, p = 0.244). Importantly, considering CT-RT+cetuximab treatment and EGFR tumoral expression (N = 21), patients with EGFR 3+ status and high ADCC showed an improved OS as compared to patients with ADCC below median value, HR = 0.09031 (95% CI, 0.009983 to 0.8170), p = 0.032 (Long-rank Mantel-Cox Test). Median OS values for patients with high EGFR expression were 34.8 months (range 9.1-53.7) and 13.1 months (range 2.1-39.5) for patients with respectively high ADCC and low ADCC. Conclusion ADCC is shown to be a strong driver of cetuximab-based therapy outcome in HNSCC. High tumoral EGFR expression and high ADCC confer a particularly long overall survival. These data suggest an ADCC-based and EGFR expression-based precision therapy under cetuximab in HNSCC and open perspectives for NK boosting. Citation Format: Cristiana Lo Nigro, Laura Lattanzio, Daniela Vivenza, Martino Monteverde, Federica Tonissi, Giuliana Strola, Marco Merlano, Gerard Milano. Treatment outcome under cetuximab-based therapy and individual ADCC capability in head and neck cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1414.
    Antibody-dependent cellular cytotoxicity (ADCC), which is activated by effector cells via immunoglobulin G (IgG) fragment C receptors (FcRs), was proposed as a mechanism of cetuximab efficacy. Peripheral blood mononuclear cells (PBMCs) from 23 healthy donors and 13 patients with metastatic colorectal cancer (mCRC) treated with cetuximab were tested for FcγR polymorphisms and cetuximab-mediated ADCC. ADCC was measured by chromium-51 release on a epidermal growth factor receptor (EGFR)-positive human colon cancer cell line. Overall, 86 mCRC patients were genotyped for study purposes. PBMCs harbouring the FcγRIIIa 158 V/V genotype had a significantly higher cetuximab-mediated ADCC. No correlation was found between FcγR polymorphisms and response rate or time to progression after cetuximab-based therapy. Despite the in vitro analysis showing that the FcγRIIIa 158 V/V genotype is associated with higher ADCC, clinical data do not support a predictive role of FcγRIIIa polymorphisms in mCRC treated with cetuximab.
    Fc receptor
    Citations (23)
    The EGFR monoclonal antibody cetuximab is the only approved targeted agent for treating head and neck squamous cell carcinoma (HNSCC). Yet resistance to cetuximab has hindered its activity in this disease. Intrinsic or compensatory HER3 signaling may contribute to cetuximab resistance. To investigate the therapeutic benefit of combining MM-121/SAR256212, an anti-HER3 monoclonal antibody, with cetuximab in HNSCC, we initially screened 12 HNSCC cell lines for total and phosphorylated levels of the four HER receptors. We also investigated the combination of MM-121 with cetuximab in preclinical models of HNSCC. Our results revealed that HER3 is widely expressed and activated in HNSCC cell lines. MM-121 strongly inhibited phosphorylation of HER3 and AKT. When combined with cetuximab, MM-121 exerted a more potent antitumor activity through simultaneously inhibiting the activation of HER3 and EGFR and consequently the downstream PI3K/AKT and ERK pathways in vitro. Both high and low doses of MM-121 in combination with cetuximab significantly suppressed tumor growth in xenograft models and inhibited activations of HER3, EGFR, AKT, and ERK in vivo. Our work is the first report on this new combination in HNSCC and supports the concept that HER3 inhibition may play an important role in future therapy of HNSCC. Our results open the door for further mechanistic studies to better understand the role of HER3 in resistance to EGFR inhibitors in HNSCC.
    EGFR Inhibitors
    <div>Abstract<p>The EGFR monoclonal antibody cetuximab is the only approved targeted agent for treating head and neck squamous cell carcinoma (HNSCC). Yet resistance to cetuximab has hindered its activity in this disease. Intrinsic or compensatory HER3 signaling may contribute to cetuximab resistance. To investigate the therapeutic benefit of combining MM-121/SAR256212, an anti-HER3 monoclonal antibody, with cetuximab in HNSCC, we initially screened 12 HNSCC cell lines for total and phosphorylated levels of the four HER receptors. We also investigated the combination of MM-121 with cetuximab in preclinical models of HNSCC. Our results revealed that HER3 is widely expressed and activated in HNSCC cell lines. MM-121 strongly inhibited phosphorylation of HER3 and AKT. When combined with cetuximab, MM-121 exerted a more potent antitumor activity through simultaneously inhibiting the activation of HER3 and EGFR and consequently the downstream PI3K/AKT and ERK pathways <i>in vitro</i>. Both high and low doses of MM-121 in combination with cetuximab significantly suppressed tumor growth in xenograft models and inhibited activations of HER3, EGFR, AKT, and ERK <i>in vivo</i>. Our work is the first report on this new combination in HNSCC and supports the concept that HER3 inhibition may play an important role in future therapy of HNSCC. Our results open the door for further mechanistic studies to better understand the role of HER3 in resistance to EGFR inhibitors in HNSCC. <i>Mol Cancer Ther; 13(7); 1826–36. ©2014 AACR</i>.</p></div>
    EGFR Inhibitors
    The epidermal growth factor receptor (EGFR) is overexpressed by 80-90% of squamous cell carcinoma of head and neck (HNSCC). In addition to inhibiting EGFR signal transduction, cetuximab, a monoclonal antibody targeting EGFR can also bind to fragment crystallisable domain of immunoglobulins G1 present on natural killer (NK), causing antibody-dependent cellular cytotoxicity (ADCC). However, presence of cetuximab resistance limits effective clinical management of HNSCC.In this study, differences in induction of ADCC were investigated in a panel of ten HNSCC cell lines. Tumour cells were co-cultured with NK cells and monitored using the xCELLigence RTCA.While ADCC was not influenced by HPV status, hypoxia and cetuximab resistance did affect ADCC differentially. Intrinsic cetuximab-resistant cell lines showed an increased ADCC induction, whereas exposure to hypoxia reduced ADCC. Baseline EGFR expression was not correlated with ADCC. In contrast, EGFR internalisation following cetuximab treatment was positively correlated with ADCC.These findings support the possibility that resistance against cetuximab can be overcome by NK cell-based immune reactions. As such, it provides an incentive to combine cetuximab with immunotherapeutic approaches, thereby possibly enhancing the anti-tumoural immune responses and achieving greater clinical effectiveness of EGFR-targeting agents.
    EGFR Inhibitors
    Citations (33)
    The epidermal growth factor receptor (EGFR) is a therapeutic target in head and neck squamous cell carcinoma (HNSCC). Resistance to EGFR-targeted therapies, such as cetuximab, poses a challenging problem. This study aims to characterize acquired cetuximab resistance mechanisms in HNSCC cell lines by protein phosphorylation profiling. Through this, promising combination treatments can be identified to possibly overcome acquired cetuximab resistance in HNSCC. Protein phosphorylation profiling showed increased phosphorylation of Akt1/2/3 after cetuximab treatment in acquired cetuximab resistant cells compared to cetuximab sensitive cells, which was confirmed by western blotting. Based on this protein phosphorylation profile, a novel combination treatment with cetuximab and the Akt1/2/3 inhibitor MK2206 was designed. Synergy between cetuximab and MK2206 was observed in two cetuximab sensitive HNSCC cell lines and one acquired cetuximab resistant variant in simultaneous treatment schedules. In conclusion, this study demonstrates that increased Akt1/2/3 phosphorylation seems to be characteristic for acquired cetuximab resistance in HNSCC cell lines. Our results also show an additive to synergistic interaction between cetuximab and MK2206 in simultaneous treatment schedules. These data support the hypothesis that the combination of cetuximab with PI3K/Akt pathway inhibition might be a promising novel therapeutic strategy to overcome acquired cetuximab resistance in HNSCC patients.
    EGFR Inhibitors
    Citations (15)