Therapeutic inhibition of peritoneal carcinomatosis by nanoparticle/siRNA-mediated knockdown of specific integrins and selectins

腹膜癌（PC）是胰腺癌和胃癌进展的一种常见形式，它在很大程度上导致了较差的预后。因此，迫切需要新的治疗策略，包括选择性抑制PC。在这方面，肿瘤细胞以及内皮/间皮细胞/非恶性间质细胞可以作为治疗靶点。整合素是由α-和β-亚基组成的异二聚体细胞粘附分子。某些整合素在肿瘤中上调，推测在PC中起关键作用。先前Wicklein小组的研究结果表明，整合素α2、α3、α5、α6、αV、β1和β4是最有希望被探索的。同样，在异种移植物中，E-和p -选择素被证明可以增加血液转移和PC的形成。本项目旨在探索临床前小鼠模型的新型治疗干预策略，并对选定的选择素/整合素在体外和体内的功能进行分析。对于特定的单一或联合靶基因抑制，我们将采用基于RNA分子（小干扰RNA， sirna）递送的RNA干扰（RNAi）介导的基因敲低。sirna将被配制成纳米颗粒并应用于腹腔内。一个主要的挑战是开发在腹膜中具有高稳定性和活性的纳米颗粒配方。从艾格纳集团，聚合物纳米颗粒包括低分子量聚乙烯亚胺（PEI）及其化学改性是可用的。在本项目中，这些纳米颗粒将首次进一步开发和探索PC抑制作用。除了敲低整合素，这也将涉及针对上游调节因子（PCDHB9, FBXO50），并使用整合素抑制miR-31进行miRNA替代治疗。对于延长的治疗时间，水凝胶作为持续的NP释放系统也将建立和优化关于期望的释放动力学。因此，目标包括(i)鉴定和分析基于rnai抑制PC的最佳靶基因（整合素，选择素，整合素上游基因及其组合），（ii）探索肿瘤细胞（整合素）以及内皮/间皮/非恶性基质细胞（选择素，整合素）作为靶标，（iii）开发和体外/体内优化的，用于腹腔递送治疗性sirna / mirna的聚合物纳米颗粒和缓释系统，以及（iv）使用最佳纳米颗粒系统和sirna的小鼠模型临床前治疗研究。这将包括前治疗（在肿瘤细胞暴露之前，旨在消除PC的发作），后治疗（在肿瘤细胞暴露之后，用于治疗已建立的腹膜内癌）和延长治疗方案，旨在同时实现这两个目标。

Peritoneal carcinomatosis (PC) is a common form of pancreatic and gastric carcinoma progression, which substantially contributes to the rather poor prognosis. New therapeutic strategies, including the selective inhibition of PC, are thus desperately needed. In this regard, tumor cells as well as endothelial/mesothelial/non-malignant stroma cells can be explored as therapeutic target. Integrins are heterodimeric cell adhesion molecules consisting of α- and β-subunits. Certain integrins are upregulated in tumors and putatively play a pivotal role in PC. Previous results from the Wicklein group indicate that the integrins α2, α3, α5, α6, αV, β1 and β4 are most promising for being explored. Likewise, in xenografts E- and P-selectin were demonstrated to increase hematogenous metastasis and PC formation. This project aims at the exploration of novel therapeutic intervention strategies in preclinical mouse models and the functional analyses of selected selectins/integrins in vitro and in vivo. For specific single or combined target gene inhibition, we will employ RNA interference (RNAi)-mediated gene knockdown based on the delivery of RNA molecules (small interfering RNAs, siRNAs). siRNAs will be formulated in nanoparticles and applied intraperitoneally. A major challenge is the development of nanoparticle formulations with high stability and activity in the peritoneum. From the Aigner group, polymeric nanoparticles comprising low molecular weight polyethylenimines (PEI) and chemical modifications thereof are available. In this project, these nanoparticles will be further developed and explored for the first time for PC inhibition. Beyond knockdown of integrins, this will also involve targeting upstream regulators (PCDHB9, FBXO50), and using the integrin-inhibiting miR-31 for miRNA replacement therapy. For prolonged treatment duration, hydrogels as sustained NP release systems will be established as well and optimized with regard to desired release kinetics. Objectives thus include (i) the identification and analysis of optimal target genes (integrins, selectins, integrin upstream genes and combinations thereof) for RNAi-based inhibition of PC, (ii) exploring tumor cells (integrins) as well as endothelial/mesothelial/non-malignant stroma cells (selectins, integrins) as targets, (iii) the development and in vitro / in vivo analysis of optimized, polymeric nanoparticles and sustained release systems for peritoneal delivery of therapeutic siRNAs/miRNAs, and (iv) preclinical therapy studies in mouse models, using optimal nanoparticle systems and siRNAs. This will cover pre-treatment (prior to tumor cell exposure, aiming at the abolishment of the onset of PC), post-treatment (after tumor cell exposure, for treating established intraperitoneal carcinomas) and prolonged treatment protocols, aiming at both.