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

项目摘要 治疗耐药性是胰腺导管腺癌（PDAC）高致死率的主要原因。一 PDAC的突出特征是结缔组织增生，纤维组织的形成不仅在PDAC的形成中起关键作用， 减少药物灌注，而且限制抗肿瘤免疫细胞浸润和功能。纤维组织是 主要由细胞外基质（ECM）组分透明质酸（HA）和胶原蛋白（CN）组成。先前 靶向这些主要ECM成分的方法已经在患者中引起严重的全身副作用，因此， 找到一种安全、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满足的问题 需要的我们的长期目标是开发肿瘤特异性的，基于微生物的试剂，表达功能性ECM- 降解酶这种新的策略将治疗肿瘤结缔组织增生，最大限度地减少全身毒性， 最大限度地提高治疗剂对原发性PDAC肿瘤以及远端PDAC肿瘤的渗透和疗效， 转移本建议的目的是确定减毒鼠伤寒沙门氏菌的效用 （ST）基试剂，经工程改造以表达ECM降解酶透明质酸酶（ST-HAse）， 胶原酶（ST-CN酶），在触发致密肿瘤间质塌陷和增强治疗效果， PDAC的临床相关模型。提出这项建议的理由是， 研究将确定一种可行的肿瘤靶向方法来改善PDAC中的结缔组织增生，这将使 抗癌剂，以实现其最大的治疗效果。 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PDAC中HA和CN的表达。 最大的基质塌陷，最终导致增强的渗透和治疗效果。 这一中心假设将在PDAC的相关模型中通过追求三个具体目标进行测试：（1）确定 ST-HAse/CNase双重治疗对标准治疗化疗的抗肿瘤疗效的影响;（2） 确定ST-HASE/CNase双重治疗对免疫检查点阻断治疗疗效的影响; 和（3）开发和表征在肿瘤诱导下表达HA酶和CN酶的重组ST。 发起人。 使用肿瘤定殖ST和肿瘤诱导型细菌启动子来表达ECM降解酶， 这是一种限制基质降解对肿瘤组织影响的创新策略。此外，同时 降解HA和CN将导致比单独靶向任一组分更大的肿瘤渗透性。结果 这项工作将对PDAC患者产生重大影响，因为预计它将产生一种药物， 可以在短期内优化生产和研究性新药（IND）研究， 在长期，成为一流的，微生物为基础的代理使用，以显着改善药物渗透 促结缔组织增生的原发性和转移性肿瘤，这些肿瘤是常规治疗无法达到的。

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.