CCL3 as a Developmental Therapeutic to Enhance Brain Tumor Therapy

摘要：恶性原发性脑肿瘤是儿童癌症死亡的最常见原因 而且比肾癌和黑色素瘤的死亡人数还要多。胶质母细胞瘤（GBM）是 一致致死，并且目前的治疗是非特异性的，并且产生<15个月的中位总生存期。在 相比之下，免疫疗法承诺了一种精确的方法，大量证据表明T 细胞可以根除小鼠和人类中的大型，良好的肿瘤，即使肿瘤位于细胞内， 个脑袋携带肿瘤抗原的树突状细胞（DC）可以作为疫苗递送并迁移到引流管。 淋巴结（DLN），以触发形成有效的肿瘤特异性细胞毒性T淋巴细胞（CTL）， 根除肿瘤而不伤害正常组织。然而，尽管个别案件显着 患者对抗肿瘤DC疫苗接种的反应，早期临床试验中的总体客观反应， 低于15%。疫苗递送的DC的迁移率低（~5%），临床前研究表明， 表明用炎性细胞因子预处理疫苗部位可以增加DC迁移 与DLN结合，并成比例地增加抗原特异性T细胞应答的幅度。我们 假设用破伤风/白喉类毒素（Td）中的回忆抗原预处理疫苗部位 将诱导炎症，增加DC迁移，并引发更一致有效的抗肿瘤免疫。 在最近发表在《自然》杂志上的一项针对新诊断GBM患者的研究中，我们证明了单方面 用Td预处理一个疫苗位点导致双侧DC向DLN的迁移增加， 无进展生存期和OS显著增加-6例Td治疗患者中有3例存活超过4.5年 年一个概括性的小鼠模型证实了这些发现，表明Td预处理， 增强系统性DC向DLN的迁移并以抗原依赖性方式抑制肿瘤生长。 对患者和小鼠血清的检查显示，趋化因子（C-C基序）配体3（CCL 3）是趋化因子受体。 只有细胞因子或趋化因子在Td预处理后显著上调。此外，在小鼠中， 表明Td预处理后DC迁移的全身性增加依赖于CD 4 + 记忆效应T细胞（CD 4 Td − T）和CCL 3。然而，我们实验室最近的试验数据表明， CD 4 Td − T实际上负责CCL 3的产生，这表明CCL 3是主要的驱动因素。 Td预处理改善的抗原依赖性免疫。我们假设除了 增强DC向DLN的迁移，CCL 3直接增加抗原特异性T细胞数量， 功能性以及免疫细胞向肿瘤的运输。该提案将机械地确定 CCL 3在DC迁移、抗原特异性T细胞应答以及免疫细胞运输中的特异性作用，以及 将进一步评估DC疫苗接种的抗肿瘤功效是否可以通过使用外源性免疫抑制剂来进一步增强。 CCL 3作为疫苗增强药物。

ABSTRACT: Malignant primary brain tumors represent the most frequent cause of cancer death in children and young adults and account for more deaths than cancer of the kidney or melanoma. Glioblastoma (GBM) is uniformly lethal, and current therapy is non-specific and produces a median overall survival of <15 months. In contrast, immunotherapy promises an exquisitely precise approach, and substantial evidence suggests that T cells can eradicate large, well-established tumors in mice and humans even when tumors reside within the brain. Dendritic cells (DCs) bearing tumor antigen can be delivered as a vaccine and migrate to the draining lymph nodes (DLN) to trigger the formation of potent tumor-specific cytotoxic T lymphocytes (CTLs) capable of eradicating tumor while leaving normal tissue unharmed. However, despite individual cases of remarkable patient responses to antitumor DC vaccination, overall objective responses in early phase clinical trials have remained under 15%. The migration of vaccine-delivered DCs is low (~5%), and preclinical studies have demonstrated that preconditioning the vaccine site with the inflammatory cytokines can increase DC migration to the DLN and proportionately increase the magnitude of the antigen-specific T cell response. We hypothesized that preconditioning the vaccine site with the recall antigens in Tetanus/diphtheria toxoid (Td) would induce inflammation, increase DC migration, and elicit more consistently efficacious antitumor immunity. In a recent study in patients with newly diagnosed GBM published in Nature, we demonstrated that unilaterally preconditioning one vaccine site with Td resulted in increased bilateral DC migration to the DLNs and a significant increase in progression free survival and OS - with three of the six Td treated patients living past 4.5 years. A recapitulative murine model corroborated these findings, demonstrating that Td preconditioning both enhanced systemic DC migration to the DLNs and suppressed tumor growth in an antigen-dependent manner. Examination of both patient and murine sera revealed that the chemokine (C-C motif) ligand 3 (CCL3) was the only cytokine or chemokine significantly upregulated after Td preconditioning. Furthermore, in mice we demonstrated that the systemic increase in DC migration after Td preconditioning is dependent upon CD4+ memory effector T cells (CD4Td−mem) and CCL3. However, recent pilot data from our laboratory indicate that the CD4Td−mem are actually responsible for the production of CCL3, suggesting CCL3 serves as the primary driver of the improved antigen-dependent immunity from Td preconditioning. We hypothesize that in addition to enhancing the migration of DCs to the DLN, that CCL3 directly increases antigen-specific T cell magnitude and functionality as well as immune cell trafficking to tumor. This proposal will mechanistically determine the specific role of CCL3 in DC migration, antigen-specific T cell responses, as well as immune cell trafficking, and will further assess if the antitumor efficacy of DC vaccination can be further enhanced by the use of exogenous CCL3 as a vaccine-enhancing drug.