VEGFR2/CD133双靶向雷帕霉素脂质多聚物纳米载体抗血管瘤作用和机制研究

Rapamycin could exert its anti-angiogenic activity by inhibiting the proliferation of vascular endothelial cells. Using the feature of high expression of vascular endothelial growth factor receptor 2 (VEGFR2) in hemangioma endothelial cells, we previously constructed a novel VEGFR2-targeting lipid polymer nanocarrier containing rapamycin to target hemangiomas. Recent studies have revealed that CD133-positive hemangioma stem cells are the seed cells of hemangiomas, and play an important role in the development and progression of hemangiomas. Thus, the combined elimination of both hemangioma endothelial cells and stem cells could effectively inhibit the proliferation of hemangiomas. The aim of this study is to target both hemangioma endothelial cells and stem cells. Based on the VEGFR2-targeting lipid polymer nanocarrier constructed in our previous study, we will construct VEGFR2/CD133 dual targeting lipid polymer rapamycin nanocarriers to target hemangioma endothelial cells and stem cells. We will conduct a systematic study on the characteristics, targeting and activity of dual targeting lipid polymer nanocarriers on hemangioma endothelial cells and stem cells. This study, for the first time, makes use of the new strategy of dual-targeting lipid polymer nanocarriers to achieve dual targeting of hemangioma endothelial cells and stem cells, providing new ideas for the treatment of hemangiomas.

雷帕霉素可通过抑制血管瘤内皮细胞增殖发挥抗血管瘤活性。利用血管瘤内皮细胞高表达血管内皮生长因子受体2（VEGFR2）的特点，我们在前期工作中构建了新型雷帕霉素VEGFR2靶向脂质多聚物纳米载体实现了对血管瘤靶向治疗。最新研究显示，CD133阳性血管瘤干细胞是血管瘤的种子细胞，在血管瘤的发生和发展中起重要作用。因此，联合杀伤血管瘤内皮细胞和干细胞将更能有效抑制血管瘤增殖。本研究将从双重靶向杀伤血管瘤内皮细胞和干细胞入手，在我们前期构建的VEGFR2靶向脂质多聚物纳米载体基础上，构建VEGFR2/CD133双靶向雷帕霉素脂质多聚物纳米载体实现对血管瘤内皮细胞和干细胞的联合杀伤。本研究拟对双靶向雷帕霉素脂质多聚物纳米载体的纳米表征、对血管瘤内皮细胞和干细胞的体内外靶向性和抗血管瘤作用进行探讨。该研究首次利用双靶向纳米载体的新策略实现对血管瘤内皮细胞和干细胞的联合杀伤，为血管瘤治疗提供新思路。

我们之前开发了几种包封雷帕霉素的纳米颗粒，以实现雷帕霉素的持续释放来治疗血管瘤。然而，缺乏内在靶向性和容易被免疫系统清除是人工制造的纳米粒子必须克服的主要障碍。我们构建了包裹雷帕霉素的巨噬细胞衍生外泌体纳米微球(RNM)，以实现对血管瘤进行持续靶向治疗的目标。首先通过基于挤压的方法从U937细胞(人类巨噬细胞系)制备了雷帕霉素包封的外泌体纳米颗粒(RN)。然后，用PLGA(聚乳酸-羟基乙酸共聚物)微球包封RN以获得RNM。研究了RN和RNM在血管瘤干细胞上的释放特性、靶向性和生物活性。RN的直径大小为100纳米，雷帕霉素包封率(EE)为83%。制备的RNM的粒径约为30 μm，RNM的EE为34%。RNM的缓释可显著达到40天。正如预期的那样，RN和RNM在人胚胎干细胞中显示出有效的细胞增殖抑制，显著的细胞凋亡，以及显著的血管生成因子表达抑制。我们的结果表明，RNM是一种延长和有效地将雷帕霉素递送至血管瘤的有效方法。