靶向肿瘤间质的脂双层包被介孔硅纳米粒共载和厚朴酚与吉西他滨协同治疗胰腺癌的研究

The pancreatic cancer is characteristic of extensive tumor stroma and desmoplastic reaction, both of which result in low response to chemotherapy and chemo-resistance in pancreatic cancer. In previous study, we found that honokiol could suppress SHH protein expression and induce apoptosis for pancreatic tumor by interfering with tumor-stromal cross-talk. Thus, we favor the hypothesis that the combination of honokiol and gemcitabine can improve the treatment of pancreatic cancer. At the same time, to overcome the drawback that drugs with different solubility are difficult to be encapsulated together, we construct lipid bilayer coated mesoporous silica nanoparticles for synergistic honokiol and gemcitabine delivery. And this delivery system was further modified with Syndecan-1 protein to achieve specific targeting of stroma for pancreatic tumor. The effect of this multifunctional nanoparticles on cellular uptake, cytotoxicity, cell cycle, apoptosis and key signal molecules in SHH pathway are evaluated in vitro. And the in vivo tumor targeting, inhibition ratio of tumor growth, in vivo toxicity assessment of this nanoparticles are verified on nude mice bearing pancreatic tumor and stroma xenografts. In addition, the expression of tumor stroma and desmoplastic reaction marker proteins was also determined by immunohistochemical analyses. The mechanism of improving the therapeutic effect of pancreatic tumor was elucidated by comprehensive in vitro and in vivo experimental results. This study will provide a new idea for the treatment of pancreatic tumor, and it will provide scientific basis for the future clinical application of this new type of nano-drug delivery system.

胰腺癌特有的致密间质和结缔组织增生性反应是其化疗响应低和产生耐药的主要原因。我们前期研究发现和厚朴酚能够下调SHH蛋白表达，诱导胰腺癌细胞凋亡。据此，我们设想将其与吉西他滨联合，通过和厚朴酚抑制胰腺癌与间质细胞间cross-talk作用，降低致密间质，增加吉西他滨向肿瘤内部递送，提高胰腺癌疗效。同时，针对溶解度不同药物难以共包封的问题，本课题拟构建脂双分子层包裹的介孔二氧化硅纳米粒递送和厚朴酚与吉西他滨，并用Syndecan-1蛋白修饰该纳米粒，实现对胰腺癌间质特异性靶向。体外评价该多功能纳米粒的细胞摄取、毒性、周期、凋亡和调控SHH通路信号分子的作用。构建荷瘤小鼠，观察该纳米粒体内肿瘤靶向、抑瘤率、毒性及对间质结缔组织标志蛋白的影响。综合体内外实验结果阐明提高胰腺癌疗效的分子机制。本项目为胰腺癌治疗探索研究提供新的思路，同时为该类新型纳米递送系统的未来临床转化应用提供科学依据。

胰腺癌特有的大量间质和促结缔组织增生性反应是胰腺癌发生耐药和转移的最主要原因。因此，仅仅作用于胰腺癌细胞本身的治疗策略难以发挥理想效果。针对胰腺癌难治性的核心病机，本研究将中药活性成分和厚朴酚(HNK)、化疗药吉西他滨(GEM)与脂双分子层包裹的介孔硅纳米粒相联合，利用两种药物诱导胰腺癌细胞凋亡，降低胰腺癌致密间质，再结合多功能纳米粒高效递药的性能，对胰腺癌细胞及其赖以生存的肿瘤间质微环境发挥双重作用以增强药效。本项目利用Syndecan-1 修饰的脂双层包被介孔二氧化硅纳米粒子，靶向递送HNK与GEM至胰腺癌间质和肿瘤部。制得的SDC1-LB-MSN-GEM/HNK纳米粒粒径在251.7 nm左右，体外细胞靶向性研究结果证实其在BXPC-3人胰腺肿瘤细胞模型上具有更好的摄取，且抑制细胞生长活力和诱导细胞凋亡的能力也更强。3D肿瘤球模型试验证实SDC1-LB-MSN-GEM/HNK具有更好的肿瘤球生长抑制能力。机理研究结果表明该SDC1-LB-MSN-GEM/HNK能够通过调控线粒体凋亡信号通路诱导细胞凋亡。并通过抑制SHH信号通路，降低胰腺癌致密间质更好的发挥药物抗胰腺癌的作用。体内活体成像结果证实SDC1-LB-MSN具更好的胰腺肿瘤靶向性。药效学研究结果表明，该多功能纳米粒能显著提高对于小鼠胰腺肿瘤的治疗效果，体内外安全性好。本项目整合传统中药与化疗药优势，结合现代靶向纳米医学的先进技术，为中西药结合抗肿瘤治疗提供了一种新的方法和思路，同时为该类新型纳米递送系统的未来临床转化提供科学依据。