PHOTODYNAMIC THERAPY (PDT) AND TUMOR IMMUNITY

描述(由申请人提供)： 光动力疗法(PDT)治疗的肿瘤细胞在小鼠癌症模型中已被证明是有效的抗肿瘤疫苗，在治疗和预防环境中都是如此。然而，PDT增强肿瘤免疫原性的机制尚不清楚。PDT对肿瘤细胞的治疗已被证明可以诱导“危险”信号的释放，能够刺激抗肿瘤免疫。危险信号由危险信号受体、Toll样受体(TLRs)和Noll-Lie受体(NLRs)识别。我们和其他人已经证明，经PDT处理的肿瘤细胞含有TLR配体。在一项新的发现中，我们现在表明，经PDT治疗的肿瘤细胞刺激危险受体NLR家族。我们推测TLR和NLR的激活在PDT增强抗肿瘤免疫中起关键作用。此外，我们假设PDT或PDT疫苗与增强危险信号通路诱导的治疗相结合，将进一步增强抗肿瘤免疫的诱导，并将在更具侵袭性的、自发转移的肿瘤模型中导致对远处疾病的增强控制。因此，我们建议将PDT与通过与PDT处理的肿瘤细胞诱导的信号通路互补的信号通路来增强免疫反应的药物相结合，以增强PDT疫苗或PDT诱导的抗肿瘤免疫反应。最后，我们已经证明，在黑色素瘤临床前模型中，PDT治疗的肿瘤细胞可以在辅助环境中用于增强手术切除后的抗肿瘤免疫。我们现在建议将这些发现扩展到临床环境中，通过调查手术切除肿瘤后晚期III期黑色素瘤的自体PDT疫苗的安全性和免疫原性。这次更新的总体目标是了解PDT增强肿瘤细胞免疫原性的机制，长期目标是开发临床PDT方案，增强抗肿瘤免疫和对抗继发性疾病。我们目前的目标是了解PDT促进抗肿瘤免疫的机制，以促进临床PDT方案的发展，既控制肿瘤的长期生长，又促进抗肿瘤免疫。计划了三个具体目标，以使我们能够检验我们的假设并实现这一目标。前两个目标是临床前和协同作用；特定目标1研究了PDT治疗的肿瘤细胞激活NLR家族成员NALP3的机制。具体目标2探索使用TLR激动剂来增强PDT产生的疫苗的抗肿瘤效果。这项应用的最终结果是《特定目标3》，它测试了PDT疫苗的临床应用。光动力疗法对于越来越多的恶性肿瘤是一种有效的治疗方法，然而，光动力疗法的复杂性阻碍了光动力疗法的优化。我们的研究将有助于PDT的优化，并允许开发其增强抗肿瘤免疫的能力。 公共卫生相关性： 晚期淋巴转移性黑色素瘤患者的长期预后较差。黑色素瘤的主要治疗方法仍然是手术切除，这可以治愈早期疾病，但对转移性疾病影响很小。尽管付出了巨大的努力，但在过去的30年里，黑色素瘤患者的总体预后并没有改善。近年来，一些黑色素瘤疫苗已经被研究；然而，尽管有希望的I-II期研究，在III期随机试验中没有观察到持久的反应。这些令人失望的结果可能是许多因素的结果，包括肿瘤诱导的免疫抑制和耐受以及肿瘤的持续生长。因此，努力的重点是开发疫苗，通过克服自然抑制因素，在辅助环境中，如与手术相结合，增强抗肿瘤免疫。我们的临床前研究表明，PDT直接改变了肿瘤细胞的免疫原性，部分是通过诱导“危险”信号。我们的建议旨在1)了解免疫细胞对PDT治疗肿瘤细胞产生的危险信号的反应，以及2)PDT疫苗通过使用联合治疗来增强抗肿瘤免疫。我们将使用这些研究的结果作为第一阶段试验的指南，该试验调查使用PDT产生的疫苗作为手术切除III期暂时性黑色素瘤患者肿瘤的辅助手段。

DESCRIPTION (provided by applicant): Photodynamic therapy (PDT) treated tumor cells have proven to be efficacious anti-tumor vaccines in both therapeutic and preventative settings in murine models of cancer. However the mechanism by which PDT enhances tumor immunogenicity is unclear. PDT treatment of tumor cells has been shown to induce the release of "danger" signals capable to stimulating anti-tumor immunity. Danger signals are recognized by danger signal receptors, Toll-like receptors (TLRs) and NOD-lie receptors (NLRs). We and others have shown that PDT treated tumor cells contain TLR ligands. In a novel finding we now show that PDT-treated tumor cells stimulate the NLR family of danger receptors. We hypothesize that activation of TLR and NLR is critical to the enhancement of anti-tumor immunity by PDT. Furthermore we hypothesize the combination of PDT or PDT vaccines with therapies that augment induction of danger signal pathways will further enhance the induction of anti-tumor immunity and will lead to enhanced control of distant disease in more aggressive, spontaneously metastasizing tumor models. Therefore we propose to combine PDT with agents that enhance the immune response through signaling pathways complimentary to those induced by PDT-treated tumor cells, in order to augment the anti-tumor immune response induced by PDT vaccines or PDT. Finally we have shown that PDT-treated tumor cells can be used in an adjuvant setting to enhance anti-tumor immunity following surgical resection in a pre-clinical model of melanoma. We now propose to extend these findings to a clinical setting by investigating the safety and immunogenicity of an autologous PDT vaccine for advanced stage III in transit melanoma following surgical resection of tumors. The overall goal of this renewal is to understand the mechanisms by which PDT enhances tumor cell immunogenicity with the long-term goal of developing clinical PDT protocols that enhance anti-tumor immunity and combat secondary disease. Our current objective is to understanding the mechanisms by which PDT promotes anti-tumor immunity in order to facilitate the development of clinical PDT regimens that both control long-term tumor growth and promote anti-tumor immunity. Three specific aims are planned to enable us to test our hypotheses and achieve this objective. The first two aims are pre-clinical and synergistic; Specific Aim 1 examines the mechanism by which PDT-treated tumor cells activate the NLR family member, NALP3. Specific Aim 2 explores the use of TLR agonists to augment the anti-tumor effects of PDT-generated vaccines. The application culminates in Specific Aim 3, which tests the clinical application of PDT-generated vaccines. PDT is an effective therapy for a growing number of malignancies, however optimization of PDT has been hindered by the complexity of the therapy. Our studies will both aid in the optimization of PDT and permit exploitation of its ability to enhance anti-tumor immunity. PUBLIC HEALTH RELEVANCE: Patients with advanced lymphatic metastatic melanoma have a poor long-term prognosis. The primary treatment for melanoma remains surgical excision, which can be curative for early disease, but has minimal effects on metastatic disease. The overall prognosis for patients with melanoma has not improved over the last 30 years despite substantial effort. In recent years a number of melanoma vaccines have been studied; however in spite of promising Phase I-II studies, no durable responses have been observed in Phase III randomized trials. These disappointing results are likely a result of a number of factors including tumor- induced immune suppression and tolerance and continued tumor growth. Thus efforts have focused on the development of vaccines that augment anti-tumor immunity by overcoming the natural suppressive factors, in an adjuvant setting, such as in combination with surgery. Our pre-clinical studies suggest that PDT directly alters tumor cell immunogenicity, in part through induction of "danger" signals. Our proposal is aimed at 1) understanding the response of immune cells to danger signals generated by PDT treatment of tumor cells and 2) enhancement of anti-tumor immunity by PDT vaccines through the use of combination treatments. We will use the results of these studies as guidelines for a Phase I trial that investigates the use of PDT-generated vaccines as adjuvants to surgical removal of tumors in patients with Stage III in-transient melanoma.