叶酸修饰的聚乙烯亚胺聚合物载PD-L1 siRNA体外靶向胃癌细胞的研究  

Using folic acid-modified polyethylenimine-SPIO nanoparticles for PD-L1 siRNA delivery to target gastric cancer

作　　者：罗信[1] 彭霞[1] 陈广成[1] 侯婧瑛[2] 吴淑云 王凌云[1] 

机构地区：[1]中山大学孙逸仙纪念医院消化内科,广东广州510120 [2]中山大学孙逸仙纪念医院急诊科,广东广州510120 [3]中山大学肿瘤防治中心胸外科,广东广州510060

出　　处：《中国病理生理杂志》2017年第12期2179-2187,共9页Chinese Journal of Pathophysiology

基　　金：广州市科技计划项目(No.201704020121)

摘　　要：目的:构建高效的siRNA纳米载体靶向SGC-7901胃癌细胞,并下调胃癌表达的程序性死亡配体1(PD-L1)。方法:检测叶酸(FA)-PEG-SS-PEI-SPION纳米载体与siRNA复合后的粒径、电位等表征;体外实验检验siRNA的结合能力、复合物细胞毒性、细胞摄入能力及转染效率;磁共振(MR)成像检测示踪能力;检验胃癌细胞PD-L1下调效应及共培养T细胞的细胞因子水平。结果:N/P比值为10时,FA-PEG-SS-PEI-SPION完全复合siRNA,形成电位为(9.14±0.80)m V、粒径为(116.7±2.5)nm的多聚复合物。靶向组的转染率为(95.06±0.44)%,与非靶向组的(93.87±1.05)%相当;平均荧光强度为1 892.67±81.51,高于非靶向组的1 324.33±186.58(P<0.05)。普鲁士蓝染色和激光共聚焦显微镜成像证实了复合物的细胞摄入。体外MR成像验证了聚合物的MR造影成像能力。靶向组PD-L1的mRNA最低相对表达量为9.07%±0.79%,Western blot显示PD-L1的表达显著降低。共培养实验显示IFN-γ和TNF-α的分泌水平增加,IL-10的分泌水平降低(P<0.05)。结论:本研究构建了FA-PEG-SS-PEI-SPION纳米载体,并证明了其体外靶向细胞及载siRNA下调PD-L1表达的能力和MR示踪的能力,是一种高效和安全的靶向治疗纳米载体。AIM： To synthesis and characterize a multi-functional siRNA delivery agent with effective thera-peutic effects and MR-tracing ability for programmed death ligand-1 （ PD-L1） positive gastric cancer SGC-7901 cell line. METHODS： The characterization, binding ability, cytotoxicity, transfection efficiency and cellular internalization of the polyplex were determined. The PD-L1 knockdown effect was analyzed, and cytokines secreted by cocultured T cells were measured. RESULTS ： We developed folic acid （ FA） -PEG-SS-PEI-SPION as siRNA delivery agent for PD-L1 knockdown. At W//3 ratio of 10,the FA-PEG-SS-PEI-SPION bound PD-L1 siRNA to form polyplex in a diameter of （116. 7 ±2. 5） nm with zeta potential of （9. 14 ±0. 80） mV. Transfection efficiency of the targeted polyplex was （ 95. 06 ± 0. 44） % ,com- pared with （93. 87 ±1.05）% of the untargeted polyplex. Mean fluorescence intensity of the targeted polyplex was 1 892. 67 ±81. 51,significantly higher than 1 324. 33 ± 186. 58 of the untargeted. The cellular magnetic resonance （MR） imaging showed the polyplex also acted as T2 weighted contrast agent for cancer MR imaging. The relative mRNA level of PD-L1 in polymer/siRNA-2 treatment group was （9. 07 ± 0. 79） % . Decreased protein expression of PD-L1 was showed by Western blot. The secretion levels of IFN-7 and TNF-a in cocultured T cells increased, while that of IL-10 decreased. CONCLUSION ： Our findings highlighted the potential of the multifunctional theranostic nanoparticles for effective targe-ting PD-LI knockdown therapy and MR imaging diagnosis in gastric cancers.

关 键 词：程序性死亡配体1 胃癌 叶酸 磁共振成像 SIRNA 

分 类 号：R0[医药卫生] R735.2