HEAD AND NECK SQUAMOUS CELL CARCINOMA

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。最近有报道称，有强有力的证据表明，HPV与头颈部鳞状细胞癌的一个独特亚群之间存在病因学关联，其特征是肿瘤细胞核中存在高危HPV DNA。这些肿瘤绝大多数是HPV16阳性。由于病毒癌蛋白E6和E7在HPV相关癌症中一致表达，并且是肿瘤特异性抗原，HPV相关头颈部鳞状细胞癌（HPV- hnscc）患者可能受益于旨在增强对HPV癌蛋白的细胞免疫反应的治疗策略。在临床前模型系统中，结核分枝杆菌热休克蛋白70 （HSP70）与hpv16e7抗原的连锁被证明可以显著增强裸DNA疫苗的效力。接种E7/HSP70 DNA的小鼠与接种野生型E7 DNA相比，HPV16 E7特异性CD8+ T细胞的频率增加了至少30倍，并对表达E7的肿瘤产生了显著的抗肿瘤作用。该疫苗对主要组织相容性复合体（MHC） I类分子下调表达e7的小鼠肿瘤表现出显著的效力，这是一个重要的发现，因为很大比例的晚期HNSCC表现出MHC I类分子的下调。重复的DNA疫苗接种诱导了不同性质的细胞毒性T淋巴细胞（CTL），具有更高的亲和力和增强的抗肿瘤保护作用。此外，在DNA疫苗的E7(detox)/HSP70中添加信号肽可显著提高肌内免疫方法的免疫效果。在关键Rb结合残基发生突变的E7基因（称为E7排毒）无法结合Rb，没有转化活性，但仍保持了强免疫原性。GMP级Sig-E7（排毒）/HSP70在pNGVL4a DNA骨干中已被制造用于临床试验，由NIH快速获取干预发展计划的支持。提出了一项开放标签、剂量递增试验，以评估HPV16-HNSCC患者肌肉注射E7（排毒）HSP70 DNA疫苗的安全性、可行性和免疫活性的初步证据。免疫活性将通过使用ELISPOT、CTL、四聚体染色和细胞内细胞因子染色测量E7特异性T细胞介导的免疫反应来评估，然后进行流式细胞术分析，以及通过测量HPV16 E7抗体滴度来测量体液免疫反应。在未来的II期试验中，将对安全、可行和有免疫活性证据的剂量进行研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Strong evidence of an etiologic association between HPV and a distinct subset of head and neck squamous cell carcinomas, distinguished by the presence of high-risk HPV DNA in tumor cell nuclei, has recently been reported. These tumors are overwhelmingly HPV16 positive. Because viral oncoproteins E6 and E7 are consistently expressed in HPV-associated cancers and are tumor-specific antigens, patients with HPV-associated head and neck squamous cell carcinoma (HPV-HNSCC) may benefit from therapeutic strategies designed to augment the cellular immune response to HPV oncoproteins. In preclinical model systems, linkage of Mycobacterium tuberculosis heat shock protein 70 (HSP70) to the HPV16 E7 antigen was demonstrated to significantly enhanced the potency of a naked DNA vaccine. Vaccination of mice with E7/HSP70 DNA increased the frequency of HPV16 E7-specific CD8+ T cells by at least 30-fold compared to vaccination with wild-type E7 DNA and generated a significant antitumor effect against an E7-expressing tumor. This vaccine demonstrated significant potency against established E7-expressing murine tumors with down-regulation of Major Histocompatibility Complex (MHC) class I molecules, an important finding given a significant proportion of advanced stage HNSCC exhibit down-regulation of MHC class I molecules. Repeated DNA vaccinations elicited qualitatively different cytotoxic T lymphocytes (CTL) with higher avidity and improved protective anti-tumor effects. Furthermore, the addition of signal peptide to E7(detox)/HSP70 in the DNA vaccine significantly improved the efficacy of the intramuscular method of immunization. An E7 gene with mutations in the critical Rb binding residues (termed E7 detox) was generated which failed to bind Rb, had no transforming activity, and yet maintained potent immunogenicity. GMP grade Sig-E7(detox)/HSP70 in the pNGVL4a DNA backbone has been manufactured for clinical trials with support from the NIH Rapid Access to Intervention Development program. An open label, dose escalation trial to evaluate the safety, feasibility, and preliminary evidence of immunological activity of four intramuscular injections of the E7(detox)HSP70 DNA vaccine in patients with HPV16-HNSCC is proposed. Immunologic activity will be assessed by measurement of the E7 specific T cell-mediated immune response using ELISPOT, CTL, tetramer staining assays, and intracellular cytokine staining followed by flow cytometry analysis as well as the humoral immune response via measurement of HPV16 E7 antibody titers. The dose that is found to be safe, feasible, and to develop evidence of immunologic activity will be studied in a future phase II trial.