Macrophage Targeted Photodynamic Therapy

描述(由申请人提供)： 光动力疗法(PDT)可通过增强递送 使用靶向大分子对选定皮损的光敏剂(PS) 共轭关系。最近，肿瘤相关巨噬细胞已被接受 (TAMs)通过几种不同的机制帮助肿瘤生长和扩散 旁分泌生长因子、血管生成增加和基质降解 酶)，它们已被认为是癌症治疗的有效靶点。 这项修订后的提案调查了一种新的杀死TAMs的方法 提供经修饰的白蛋白-氯素(E6)结合物，由 TAMs上存在清道夫受体，以及肿瘤限制的照明。 我们已经证明，这种方法允许非常特定的光破坏小鼠 巨噬细胞在体外并导致对肿瘤生长的实质性抑制 体内巨噬细胞瘤和非巨噬细胞瘤均有表达。这项提案将考验 假设巨噬细胞选择性和定向结合 光照将杀死TAMS而不会伤害其他远处的巨噬细胞 从而产生有益的肿瘤反应，包括生长 延迟，减少血管生成和转移，提高存活率，以及 肿瘤免疫的发展。共轭化合物与的相互作用 巨噬细胞可能依赖于它们的细胞激活状态，而这 将通过基因表达阵列和定量检测 RT-PCR检测清道夫受体的表达。J774细胞形成高度侵袭性和 转移性S.C.BALB/c小鼠体内肿瘤及其生物分布和光动力反应 这些偶联物中的一种将与游离PS进行比较。免疫组织化学将 允许微血管密度、巨噬细胞含量和增殖指数 从治疗后的肿瘤冰冻切片中确定。一对的光动力学响应 南卡罗来纳州。巨噬细胞含量和免疫原性不同的小鼠肿瘤(EMT-6 和RIF-1)将通过目标和RIF-1的定量比较确定 非靶向PDT，有效剂量大致相等。An对光动力的增强作用 助剂(OK432)旨在增加TAMS对肿瘤的侵袭程度 并将探索如何提高它们的激活状态。现建议将一项 PDT反应是炎症性的，它会鼓励诱导特定的 抗肿瘤免疫反应，将通过重新挑战治愈来探索 具有相同和无关细胞系的动物以及效应器的测量 细胞功能(细胞毒性T淋巴细胞、自然杀伤细胞和巨噬细胞) 从脾和引流淋巴结处。

DESCRIPTION (provided by applicant): Photodynamic therapy (PDT) may be improved by enhancing the delivery of photosensitizers (PS) to selected lesions using targeted macromolecular conjugates. Recently it has become accepted that tumor-associated macrophages (TAMs) assist the tumor to grow and spread by several distinct mechanisms (paracrine growth factors, increased angiogenesis, and matrix-degrading enzymes) and they have been proposed to be a valid target for cancer therapy. This revised proposal investigates a new approach to killing TAMs by targeted delivery of modified albumin-chlorin (e6) conjugates that are recognized by the scavenger receptors present on TAMs, together with tumor-confined illumination. We have shown that this approach allows very specific photodestruction of mouse macrophages in vitro and leads to substantial inhibition of tumor growth in vivo in both macrophage and non-macrophage tumors. This proposal will test the hypothesis that the combination of macrophage selectivity and directed illumination will kill TAMs without harming other distant macrophage populations, and hence produce beneficial tumor responses including growth delay, decreased angiogenesis and metastasis, increased survival, and development of tumor immunity. The interaction of the conjugates with macrophages is likely to depend on their cellular activation state and this will be investigated with gene expression arrays and quantitation of scavenger-receptor expression by RT-PCR. J774 cells form highly aggressive and metastatic s.c. tumors in BALB/c mice and the biodistribution and PDT response of these conjugates will be compared to free PS. Immunohistochemistry will allow microvessel density, macrophage content, and proliferative index to be determined in frozen sections from treated tumors. The PDT responses of a pair of s.c. mouse tumors differing in macrophage content and immunogenicity (EMT-6 and RIF- 1) will be determined with quantitative comparison of targeted and non-targeted PDT at roughly equal effective doses. The enhancement of PDT by an adjuvant (OK432) designed to increase the degree of tumor infiltration by TAMs and to increase their activation state will be explored. It is proposed that a PDT response which is inflammatory will encourage the induction of a specific anti-tumor immune response, which will be explored by rechallenging cured animals with the same and unrelated cell lines, and measurement of effector cell functions (cytotoxic T lymphocyte, natural killer cell and macrophage) from spleens and draining lymph nodes.