Cancer therapy employing the tumour suppressing bacterium Caulobacter crescentus

我们将利用灵活的外源蛋白展示能力和细菌的抗肿瘤特性，开发一种有效的治疗性癌症疫苗。在小鼠模型中，我们将检验以下两种方法的价值：a)通过基于抗体的靶向癌症抗原和其他显示的免疫刺激物来直接刺激免疫系统成分；b)用显示肿瘤定向抗体以及癌症抗原和免疫刺激物的caulobacter靶向肿瘤。治疗性癌症疫苗方法比化疗具有显著的优势，但找到抗原、递送载体和佐剂的组合来打破能量已被证明是困难的。利用细菌治疗是一种很有前途的方法。一种（卡介苗）目前用于治疗膀胱癌。有些细菌具有抗肿瘤特性，但具有致病性，在宿主体内繁殖，因此不适合人类。这个建议提供了另一种选择。新月形茎杆菌是一种不会在哺乳动物体内复制的非病原体。它具有结晶蛋白表面(S)层，易于在高表面密度下显示大的蛋白质片段。它还具有很强的抗肿瘤特性。我们将结合这些观察结果来开发一种癌症治疗方法，这需要自然科学实验室的微生物遗传学努力来生产候选治疗方法，并结合药学实验室的配方专业知识来评估疗效和效力。l)我们将展示针对树突状细胞受体（如DEC-205）的单链抗体，同时展示癌症抗原（如MUC1和5T4）和免疫刺激物（如GM-CSF）。这是通过表达多个修饰的s层蛋白基因来实现的。我们也可以使用蛋白G （IgG结合）显示来“装载”目标单克隆的Caulobacters。2)我们还将利用针对肿瘤标记物的抗体，将疫苗配方直接靶向肿瘤，期望刺激浸润性免疫细胞。包括Lewis肺癌和EMT-6小鼠乳腺肿瘤在内的几个模型系统将进行测试，预防模式测试的最佳结果也将在治疗模式下进行评估。

We will exploit the flexible foreign protein display capabilities and the anti-tumor properties of the bacterium Caulobacter crescentus to develop a potent therapeutic cancer vaccine, hi mouse models we will examine the value of a) direct stimulation of immune system components by antibody-based targeting of cancer antigens in concert with other displayed immune stimulants and b) targeting tumors with Caulobacters displaying tumor-directed antibodies as well as cancer antigens and immune stimulants. Therapeutic cancer vaccine approaches offer significant advantages over chemotherapy, but finding the combination of antigen, delivery vehicle and adjuvanation to break anergy has proven difficult. Treatment using bacteria is a promising approach. One (BCG) is currently used for bladder cancer. Some bacteria exhibit anti-tumor properties but are pathogenic and propagate in the host and so are poorly suited for humans. This proposal offers an alternative. Caulobacter crescentus is a non-pathogen that does not replicate in mammals. It exhibits a crystalline protein surface (S) layer that is readily adapted to display large protein segments at high surface density. It also has strong anti-tumor properties. We will combine these observations to develop a therapeutic for cancer, requiring the microbial genetics efforts of a natural science lab to produce candidate therapeutics with the formulation expertise of a Pharmacy lab to evaluate efficacy and potency. Some specific Objectives: l)We will display single chain antibodies targeting receptors of dendritic cells (e.g., DEC-205) and simultaneously display cancer antigens (e.g., MUC1 and 5T4) and immune stimulants such as GM-CSF. This is done by expression of multiple modified S-layer protein genes. We can also use Protein G (IgG binding) display to "load" Caulobacters with targeting monoclonals. 2) We will also target vaccine formulations directly to tumors by use of antibodies to tumor markers, expecting to stimulate infiltrating immune cells. Several model systems will be tested including Lewis Lung Carcinoma and EMT-6 Murine Mammary tumor, the best results from prophylactic mode testing will also be evaluated in therapeutic mode.