Immune activation by cetuximab in head and neck cancer patients

描述（由申请方提供）：有令人信服的临床证据表明，表皮生长因子受体（EGFR）特异性单克隆抗体（mAb）西妥昔单抗仅对晚期头颈部鳞状细胞癌（HNC）的一个子集有效。因此，有必要了解为什么临床反应在个体之间存在差异。与EGFR酪氨酸激酶抑制剂相反，mAb的使用提高了免疫系统可能在这种临床活性中发挥作用的可能性。此外，由于西妥昔单抗治疗HNC细胞在体外不诱导显著的细胞凋亡，体内抗肿瘤作用可能部分是由于其他因素，如通过自然杀伤（NK）细胞和单核细胞介导的抗体依赖性细胞毒性（ADCC）的免疫细胞活化，通过恒定片段（Fc）结构域的mAb结合多态性Fc？受体（Fc？R）。然而，很少有人知道是否T细胞有助于单克隆抗体治疗或是否多态性Fc？Rs影响T细胞应答的诱导。HNC细胞的HLA I类抗原加工机制（APM）的频繁下调和NK抑制分子的表达可能提供了HNC细胞对NK细胞和肿瘤抗原特异性T细胞裂解的抗性机制。因此，我们假设免疫系统的细胞臂在介导西妥昔单抗的抗肿瘤作用中起重要作用。我们有证据表明FC？R多态性在Fc？RIIa 131 R/H和FcRIII 158 V/F影响健康供体和HNC患者PBMC中的ADCC活性，并且这些密码子也与用单药西妥昔单抗治疗的结直肠癌患者的结果相关。此外，我们已经确定TNF-α，IFN-β，MIP-1a和MIP-1？在体外一致地表达于ADCC应答PBMC的上清液中。从活化的NK细胞释放，这些细胞因子和趋化因子对T细胞和树突状细胞（DC）细胞具有趋化性，表明西妥昔单抗诱导的NK裂解和TA特异性T细胞诱导的诱导之间存在潜在联系。了解这些单抗的免疫介导的机制是很重要的：（i）选择最合适的西妥昔单抗治疗的患者具有最大的能力，安装免疫激活，（ii）以提高抗肿瘤ADCC和T细胞活性，以增加西妥昔单抗治疗的患者的反应和（ii）确定生物学和临床反应的预测性免疫生物标志物，如Fc？基因多态性、细胞免疫和免疫逃逸机制。不同水平的EGFR表达和淋巴细胞的HNC小鼠模型，其特征在于Fc？来自不同疾病阶段的HNC患者的R基因型，在存在或不存在放化疗或肿瘤表达的NK抑制分子的情况下，将用于检验PBMC表达某些Fc？R基因型或晚期HNC患者影响抗肿瘤活性。此外，我们将确定西妥昔单抗是否通过DC成熟和交叉呈递增强抗原特异性T细胞诱导，这是受Fc？R多态性、西妥昔单抗和NK细胞。最后，我们建议确定西妥昔单抗在HNC患者中的反应性对NK和T细胞活化、肿瘤浸润以及来自匹兹堡大学的II期单药西妥昔单抗临床试验（08-013）的HNC标本中APM表达缺陷的影响。 公共卫生相关性：令人信服的证据表明，EGFR特异性单克隆抗体（mAb）西妥昔单抗的免疫治疗在晚期头颈部鳞状细胞癌（HNC）的治疗中是有效的，但只有20%的治疗患者。对基于西妥昔单抗的免疫治疗的差异临床应答的潜在机制尚不清楚。这些信息的缺乏对优化基于西妥昔单抗的免疫疗法的策略的开发和待治疗患者的选择具有负面影响。

DESCRIPTION (provided by applicant): There is convincing clinical evidence that the epidermal growth factor receptor (EGFR)-specific monoclonal antibody (mAb), cetuximab, is effective therapy only for a subset of advanced head and neck squamous cell carcinoma (HNC). Thus, there is a need to understand why clinical responses vary between individuals. In contrast to EGFR tyrosine kinase inhibitors, the use of a mAb raises the potential that the immune system might play a role in this clinical activity. Also, since treatment of HNC cells with cetuximab does not induce significant apoptosis in vitro, anti-tumor effects in vivo may be due in part to additional factors, such as immune cell activation through antibody dependent cellular cytotoxicity (ADCC) mediated by natural killer (NK) cells and monocytes, through the constant fragment (Fc) domain of the mAb binding to polymorphic Fc? receptors (Fc?R). However, little is known about whether T cells contribute to mAb therapies or whether polymorphic Fc?Rs influence the induction of T cell responses. The frequent downregulation of HLA class I antigen processing machinery (APM) and expression of NK inhibitory molecules by HNC cells, may provide a mechanism of resistance to NK cell- and tumor antigen specific T cell lysis of HNC cells. Thus, we hypothesize that the cellular arm of the immune system plays an important role in mediating the anti-tumor effects of cetuximab. We have evidence that Fc?R polymorphisms at Fc?RIIa131R/H and FcRIII158V/F influence ADCC activity in PBMC of healthy donors and HNC patients, and these codons also correlate with outcome of colorectal cancer patients treated with single agent cetuximab. In addition, we have identified that TNF-a, IFN-?, MIP-1a, and MIP-1¿, are consistently expressed in vitro in the supernatant of ADCC responding PBMC. Released from activated NK cells, these cytokines and chemokines are chemotactic for T cells and dendritic cells (DC) cells, suggesting a potential link between cetuximab-induced NK lysis and induction of TA-specific T cell induction. Understanding immune mediated mechanisms of these mAb is important: (i) to select the most appropriate patients for cetuximab therapy with greatest ability to mount immune activation, (ii) to enhance anti-tumor ADCC and T cell activity in order to increase responses in cetuximab-treated patients and (ii) to identify predictive immune biomarkers of biological and clinical responsiveness, such as Fc?R polymorphisms, cellular immunity and immune escape mechanisms. A HNC murine model with different levels of EGFR expression and lymphocytes, characterized by Fc?R genotype from HNC patients of different disease stage and in the presence or absence of chemoradiotherapy or NK inhibitory molecules expressed by the tumor, will be used to test the hypothesis that PBMC expressing certain Fc?R genotypes or from advanced HNC patients influences antitumor activity. In addition we will determine whether cetuximab enhances antigen specific T cell induction by DC maturation and cross-presentation, which is influenced by Fc?R polymorphisms, cetuximab and NK cells. Lastly we propose to determine the effect of cetuximab responsiveness in HNC patients on NK and T cell activation, tumor infiltration, and defects in APM expression in HNC specimens from a phase II, single agent cetuximab clinical trial (08-013) at the University of Pittsburgh. PUBLIC HEALTH RELEVANCE: Convincing evidence indicates that immunotherapy with the EGFR-specific monoclonal antibody (mAb) cetuximab is effective in the treatment of advanced head and neck squamous cell carcinoma (HNC), but in only 20% of the treated patients. The mechanism(s) underlying the differential clinical response to cetuximab-based immunotherapy are not known. The lack of this information has negative impact on the development of strategies to optimize cetuximab-based immunotherapy and the selection of patients to be treated.