Engineering bacteriophage Qβ conjugates with tumor associated carbohydrate antigens as multi-component anti-cancer vaccines

项目摘要 靶向肿瘤相关碳水化合物抗原（TACAs）的抗癌疫苗是例外的 因为许多TACA在多种类型的癌细胞上高度表达， 在正常细胞中表达。虽然已经实现了利用抗TACA单克隆抗体的被动免疫， 临床成功，开发基于TACA的免疫原以引发有效的抗癌免疫， 由于TACA的免疫原性极低，因此非常困难。为了应对这一挑战，令人兴奋的 已经获得的初步结果表明，以TACA为基础的疫苗可以显著减少癌症 通过使用病毒样颗粒噬菌体Qβ递送原型TACA（Tn抗原）诱导死亡。 在这项提案中，基于TACA的癌症疫苗设计的新领域将继续被打破， 工程化Qβ以产生强大的抗癌免疫反应。在令人兴奋的初步结果的基础上， 在目的1中，将靶向一种重要的肿瘤相关糖肽抗原人MUC-1携带Tn聚糖。 以Qβ为载体，可诱导产生超高滴度的抗MUC 1-Tn的IgG抗体， 减少小鼠肿瘤生长，甚至在耐受人MUC 1的转基因小鼠中。除了Tn和肿瘤 相关的MUC 1糖肽，其他TACA包括GD 2和SSEA-3将作为疫苗靶标进行研究 为了降低肿瘤逃避免疫监视的风险，并杀死所谓的癌症干细胞， 导致对传统治疗如化疗产生抗药性。此外，在晶体结构的引导下， Qβ，Qβ突变体将被开发，以减少不需要的抗Q β抗体，并进一步加强所需的抗Q β抗体。 TACA回应。细胞毒性T细胞也可以杀死癌细胞。在目标2中，Qβ将被设计为提供细胞毒性 除了产生抗TACA IgG抗体之外，T细胞表位和内置佐剂。综合 Qβ-TACA-细胞毒性T细胞表位缀合物诱导的抗体和细胞毒性T细胞免疫应答应 为免疫宿主提供抗肿瘤发展的上级保护。为未来的发展奠定基础 在目标3中，将确定疫苗在治疗犬癌症患者中的功效。犬科动物可以 这些动物是人类疾病的临床相关大型动物模型，因为它们的高生物学活性， 与人类癌症相似。这将是第一次对这种基于TACA的疫苗构建体进行此类试验， 犬类患者 总体影响：该项目将建立一个Qβ疫苗平台，大大上级目前可用的 载体递送TACA和细胞毒性T细胞表位，这将引发持久的抗TACA IgG 用于癌症治疗的抗体和细胞毒性T细胞。更深入地了解 Qβ-TACA偶联物的结构特征和抗肿瘤免疫将对癌症产生持续的影响 疫苗设计和成功的TACA为基础的抗癌疫苗是必不可少的。

Project Summary Targeting tumor-associated carbohydrate antigens (TACAs) for anticancer vaccines is exceptionally attractive because many TACAs are highly expressed on multiple types of cancer cells with no or negligible expression on normal cells. While passive immunity utilizing anti-TACA monoclonal antibodies has achieved clinical success, developing a TACA based immunogen to elicit effective anti-cancer immunity has been extremely difficult due to the notoriously low immunogenicity of TACAs. To address this challenge, exciting preliminary results have been obtained showing that TACA-based vaccines can significantly reduce cancer induced death by delivering a prototypical TACA, the Tn antigen, using virus like particle bacteriophage Qβ. In this proposal, new ground in TACA based cancer vaccine design will continue to be broken by engineering Qβ to generate powerful anti-cancer immune responses. Building on the exciting preliminary results, in Aim 1, an important tumor associated glycopeptide antigen human MUC-1 bearing Tn glycan will be targeted. Using Qβ as the carrier, super-high titers of IgG antibodies were elicited against MUC1-Tn, which significantly reduced tumor growth in mice, even in transgenic mice tolerant to human MUC1. Besides Tn and tumor associated MUC1 glycopeptides, other TACAs including GD2 and SSEA-3 will be investigated as vaccine targets to reduce the risk of tumor escape from immune surveillance and to kill purported cancer stem cells, a possible cause for resistance to traditional treatments such as chemotherapy. In addition, guided by the crystal structure of Qβ, Qβ mutants will be developed to reduce undesirable anti-Qβ antibodies and further boost desired anti- TACA responses. Cytotoxic T cells can also kill cancer cells. In Aim 2, Qβ will be engineered to deliver cytotoxic T cell epitopes and built-in adjuvants in addition to generating anti-TACA IgG antibodies. The comprehensive antibody and cytotoxic T cell immune responses induced by Qβ-TACA-cytotoxic T cell epitope conjugate should provide superior protection to immunized host against tumor development. To lay the groundwork for future translation, in Aim 3, the vaccine efficacy in treating canine cancer patients will be established. Canines can naturally develop cancer, which are clinically relevant large animal models for human diseases due to their high similarities to human cancer. This will be the first of its kind trial of such TACA based vaccine constructs in canine patients. Overall impacts: This project will establish a Qβ vaccine platform vastly superior to currently available carriers to deliver both TACAs and cytotoxic T cell epitopes, which will elicit long-lasting anti-TACA IgG antibodies and cytotoxic T cells for cancer treatment. Deeper understanding of the connections between structural features of Qβ-TACA conjugates and anti-tumor immunity will exert a sustained impact on cancer vaccine design and is essential for successful TACA-based anti-cancer vaccines.