聚集诱导发光光敏剂和PAK1抑制剂共载的靶向纳米系统增强胆管癌疗效及机制研究

Photodynamic therapy (PDT) is a local, minimally invasive and effective therapeutic technique for unresectable cholangiocarcinoma (CC). However, it still faces some problems such as poor selective of photosensitizer (PS), therapy resistance and tumor recurrence. In our previous study, We fully took advantage of a red emissive aggregation- induced emission (AIE) PS to fabricate CC targeted organic theranostic AIE nanodots for image- guided PDT. The obtained AIE nanodots exhibit high specificity to cholangiocarcinoma as well as excellent antitumor effect. Furthermore, different from conventional PSs, the AIE nanodots do not suffer from aggregation- caused fluorescence quenching and reduction in reactive oxygen species production when the AIE PS molecules are in an aggregated state. However, how to reduce resistance and recurrence after treatment remain challenges to improve therapeutic effect. We recently found that PDT could induce PAK1 overexpression and phosphorylation at Thr423. Inhibition of the activity of PAK1 can effectively enhance the sensitivity of CC cells to PDT and repress angiogenesis after treatment. These results suggest PAK1 may be an ideal target for enhanced PDT. As a continuation and expansion of our previous studies, this project is intended to fabricate a targeted nano- system for the co- loading of AIE PS (TTD) and PAK1 inhibitor (IPA-3). The synergistic effect of this nano- system on enhanced PDT will investigate both in vivo and in vitro. Molecular mechanism of PAK1 sensitizing PDT and inhibiting angiogenesis after treatment will be explored. This project will provide new strategy for improving the therapeutic effect of PDT and have high value for future translational research.

对于中晚期不可切除胆管癌，光动力治疗(PDT)是一种局部、微创、有效的治疗方法，但仍面临光敏剂特异性差、治疗抵抗和复发等难题。前期我们利用聚集诱导发光(AIE)特性的荧光分子作为光敏剂，成功制备了胆管癌靶向的诊疗一体化纳米探针，在改善肿瘤靶向性的同时，还克服了传统光敏剂聚集诱导淬灭效应。但治疗抵抗和肿瘤复发依然是阻碍PDT疗效进一步提高的瓶颈。预实验发现，抑制P21活化激酶1 (PAK1)的活性能有效增强胆管癌细胞对PDT的敏感性，并抑制PDT后细胞血管生成因子的表达，提示PAK1可作为一个有效增强PDT疗效的靶点。本项目作为前期研究的延续和拓展拟制备AIE光敏剂和PAK1抑制剂共载的靶向纳米系统，通过体内体外实验检测该纳米系统对胆管癌的协同治疗效果，并进一步探究PAK1影响 PDT敏感性及治疗后血管生成的分子机制。本研究的完成对改善胆管癌效果将提供新策略，具有较高的转化应用价值。

光动力治疗（PDT）在胆管癌等高度恶性肿瘤的临床应用中已被证实是一种确切有效的治疗手段。然而，肿瘤内部存在许多因素限制了PDT的功效。我们在前期研究中发现抑制PAK1可增强PDT疗效并并抑制PDT后细胞血管生成因子的表达。在此基础上，我们通过进一步的基因干扰探明了其中的分子机制。结果表明：1. PAK1通过调节VEGF促进肿瘤血管生成；2. PAK1的激活通过调节HIF-1a调节VEGF；3. PAK1通过泛素化蛋白酶体途径阻止HIF-1a蛋白降解；4.抑制PAK1可增强PDT疗效。接着，我们针对调节肿瘤微环境以增强PDT疗效展开了进一步研究，构建了共负载聚集诱导发光光敏剂TB与化疗药物紫杉醇的光控式靶向纳米药物，在体内外研究其对肿瘤的靶向性与治疗效果，并探讨了其增强机体抗肿瘤免疫与分子机制。研究结果表明：1. 光控式靶向纳米药物在体内外均能有效地富集在肿瘤中，其内容药物释放受到光照控制，在精准治疗的基础上实现了药物的时空控制；2. 光控式靶向纳米药物在体内外对肿瘤均起到了良好的杀伤作用，PDT与化疗联合起到了“1+1>2”的联合治疗效果；3. 光控式靶向纳米药物治疗可通过免疫原性细胞死亡效应提高肿瘤免疫原性，并上调PD-L1的表达而使肿瘤对免疫检查点抑制剂敏感。本项目基于目前PDT治疗遇到的临床困境进行了研究，从抑制肿瘤血管生成、增强肿瘤免疫原性等方面提出改善PDT的联合治疗策略，为增强PDT疗效提供了新思路与新方法