Microbial- based targeting of major extracellular matrix components for improved therapy of pancreatic cancer

项目总结 治疗抵抗是导致胰腺导管腺癌(PDAC)高致死率的主要原因。一个 PDAC的突出特点是纤维组织增生，纤维组织的形成不仅在 减少药物灌注量，还能限制抗肿瘤免疫细胞的浸润和功能。纤维组织是 主要由细胞外基质(ECM)、透明质酸(HA)和胶原(CN)组成。上一首 针对这些主要ECM成分的方法在患者中引起了严重的全身副作用，因此， 寻找一种安全、有效的方法来破坏PDAC ECM并改善药物输送仍然是一个关键的未完成的任务 需要。我们的长期目标是开发针对肿瘤的、以微生物为基础的药物，以表达功能性ECM- 降解酶。这一新的策略将治疗肿瘤间质增生，将全身毒性降至最低，并 最大限度地提高治疗药物对原发和远端PDAC肿瘤的渗透率和疗效 转移瘤。这项建议的目的是确定减毒鼠伤寒沙门氏菌的效用。 基于(ST)的试剂，设计用于表达ECM降解酶透明质酸酶(ST-Hase)和 胶原酶(ST-CNase)在触发致密的肿瘤间质塌陷和提高治疗效果中的作用 临床相关的PDAC模型。这项提议基本理由是成功地完成了这些 研究将确定一种可行的肿瘤靶向方法来改善PDAC的结缔组织发育，这将使 抗癌剂要发挥其最大的治疗效果。 我们的中心假设是，使用肿瘤特异性ST载体降解PDAC中的HA和CN将诱导 最大的间质塌陷，最终导致穿透性增强和治疗效果的提高。 这一中心假设将通过追求三个具体目标在PDAC的相关模型中得到验证：(1)确定 ST-Hase/CNase双重治疗对常规化疗抗肿瘤疗效的影响 确定双ST-Hase/CNase治疗对免疫检查点阻断治疗效果的影响； (3)构建和鉴定在肿瘤诱导下表达Hase和CNase的重组STS 推动者。 使用肿瘤定植ST和肿瘤诱导细菌启动子表达ECM降解酶 限制间质降解对肿瘤组织影响的创新策略。此外，同时 与单独靶向任何一种成分相比，降解HA和CN将导致更大的肿瘤渗透性。结果是 这项工作的结果将对PDAC患者产生重大影响，因为据预测，它将产生一种药物(S)， 在短期内，是否可以优化用于制造和研究新药(IND)的研究， 从长远来看，成为一流的微生物基剂，用于显著提高药物的渗透性 促结缔组织增生性原发和转移性肿瘤，这些肿瘤无法用常规疗法治疗。

PROJECT SUMMARY Therapeutic resistance is a major contributor to high lethality in pancreatic ductal adenocarcinoma (PDAC). A prominent feature of PDAC is desmoplasia, the formation of fibrous tissue that not only plays a critical role in reducing drug perfusion but also in limiting anti-tumor immune cell infiltration and function. The fibrous tissue is primarily composed of the extracellular matrix (ECM) components hyaluronan (HA) and collagen (CN). Previous methods to target these major ECM components have caused severe systemic side effects in patients and, thus, finding a safe, effective approach to disrupt the PDAC ECM and improve drug delivery remains a critical unmet need. Our long-term goal is to develop tumor-specific, microbial-based agents that express functional ECM- degrading enzymes. This novel strategy will remediate tumor desmoplasia, minimize systemic toxicity, and maximize the penetration and efficacy of therapeutics against primary PDAC tumors, as well as distal metastases. The objective of this proposal is to determine the utility of attenuated Salmonella typhimurium (ST)-based agents, engineered to express the ECM-degrading enzymes hyaluronidase (ST-HAse) and collagenase (ST-CNase), in triggering collapse of dense tumor stroma and in enhancing therapeutic efficacy in clinically-relevant models of PDAC. The rationale underlying this proposal is that successful completion of these studies will identify a feasible, tumor-targeting approach to ameliorate desmoplasia in PDAC, which will enable anticancer agents to achieve their greatest therapeutic effects. Our central hypothesis is that degrading both HA and CN in PDAC using tumor-specific ST vectors will induce the greatest stromal collapse, ultimately leading to enhanced penetration and efficacy of therapeutic treatment. This central hypothesis will be tested in relevant models of PDAC by pursuing three specific aims: (1) Determine the effect of dual ST-HAse/CNase treatment on the antitumor efficacy of standard-of-care chemotherapy; (2) Determine the impact of dual ST-HAse/CNase treatment on efficacy of immune checkpoint blockade therapy; and (3) Develop and characterize recombinant STs expressing HAse and CNase under tumor-inducible promoters. The use of tumor-colonizing ST and tumor-inducible bacterial promoters to express ECM-degrading enzymes is an innovative strategy to limit the effects of stromal degradation to tumor tissues. Furthermore, simultaneously degrading HA and CN will result in greater tumor permeability than targeting either component alone. The results of this work will have a significant impact for PDAC patients, because it is predicted to yield an agent(s) that can, in the short-term, be optimized for manufacturing and Investigational New Drug (IND)-enabling studies and, in the long-term, become a first-in-class, microbial-based agent used to significantly improve drug permeability of desmoplastic primary and metastatic tumors that are inaccessible to conventional therapy.