Objective: This study aimed to develop a new delivery strategy that utilized metal organic framework (MOF) loaded with small-interfering RNA (siRNA) targeting ITGAV to overcome tumor matrix barrier, and thus enhance drug penetration and immune accessibility in breast cancer. Methods: MOF@siITGAV particles were constructed and characterized. The uptake of MOF@siITGAV in breast cancer cell line 4T1 was observed by the cellular uptake assay. The toxicity of MOF@siITGAV was detected by cell counting kit 8 (CCK-8). The blank control group, naked siITGAV group and MOF@siITGAV group were set. Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) and Western blot were used to detect the expressions of ITGAV. The level of transforming growth factor β1 (TGF-β1) in the cell culture medium was detected by enzyme-linked immunosorbent assay (ELISA). The penetration of MOF@siITGAV in 4T1 cells was tested by constructing 3D spheroids. Mouse models of triple negative breast cancer were established. The effect of MOF@siITGAV on the growth of transplanted tumors and main organs was verified. Imminohistochemical (IHC) was used to test the expression of collagen and CD8. Results: MOF@siITGAV particles were constructed with sizes of (198.0±3.3) nm and zeta potential of -(20.2±0.4) mV. MOF@siITGAV could be engulfed by 4T1 cells and triggered to release siRNA. Compared to the blank control group, the expression of ITGAV in the MOF@siITGAV group [(46.5±11.3)%] and the naked siITGAV group [(109.9±19.0)%] was lower. TGF-β1 in the cell culture medium of the blank control group, naked siITGAV group, and MOF@siITGAV group was (474.5±34.4) pg/ml, (437.2±16.5) pg/ml, and (388.4±14.4) pg/ml, respectively. MOF@siITGAV could better penetrate into 4T1 spheroids and exhibit no obvious toxicity. The cell viability was (99.7±3.5)%, (98.2±5.2)%, (97.3±6.6)%, (92.1±8.1)%, and (92.4±4.1)%, respectively, after MOF@siITGAV treatment with the concentration of 0, 10, 20, 40, 80, and 160 μg/ml, respectively, for 24 h. The tumor growth in the MOF@siITGAV group was suppressed significantly. After 15-day treatment, the tumor volume of the MOF@siITGAV group was (135.3±41.9) mm3, smaller than that of the blank control group [(691.1±193.0) mm3] (P=0.025). The expression of collagen and the number of CD8 positive cells of the MOF@siITGAV group were lower than those of the other two groups. No significant abnormalities were observed in the main organs of mice. Conclusions: Targeting the integrinαv on the surface of cancer cells could destroy extracellular matrix, improve drug delivery, and increase immune infiltration.
目的： 开发一种新型递送策略，利用金属有机框架（MOF）负载针对整合素αv（ITGAV）的小干扰RNA siITGAV，以克服基质屏障，进而增强乳腺癌内药物递送及免疫可及性。 方法： 构建MOF@siITGAV颗粒，对其进行材料表征。通过细胞摄取实验观察乳腺癌4T1细胞对MOF@siITGAV的摄取情况，细胞计数试剂盒8法检测MOF@siITGAV的细胞毒性。设空白对照组、游离siITGAV组和MOF@siITGAV组，采用实时荧光定量聚合酶链反应检测各组4T1细胞中ITGAV mRNA的表达，采用Western blot检测ITGAV蛋白的表达，采用酶联免疫吸附试验检测TGF-β1的含量。采用3D球体穿透实验观察MOF@siITGAV穿透4T1细胞球的能力。建立三阴性乳腺癌小鼠模型，观察MOF@siITGAV对移植瘤生长及小鼠心、肝、脾、肺、肾等主要脏器的影响，采用免疫组化染色检测肿瘤组织中Ⅰ型胶原蛋白和CD8的表达。 结果： 成功构建MOF@siITGAV颗粒，粒径为（198.0±3.3）nm，电位为-（20.2±0.4）mV。4T1细胞能有效摄取MOF@siITGAV，并触发siRNA的有效释放，MOF@siITGAV组细胞中ITGAV mRNA和蛋白表达水平、TGF-β1的表达水平均显著下调［相对于空白对照组，游离siITGAV组和MOF@siITGAV组4T1细胞中ITGAV mRNA相对表达水平分别为（109.9±19.0）%和（46.5±11.3）%；空白对照组、MOF@siNC组和MOF@siITGAV组TGF-β1浓度分别为（474.5±34.4）pg/ml、（437.2±16.5）pg/ml和（388.4±14.4）pg/ml］。MOF@siITGAV在4T1细胞球中的穿透能力更强，对4T1细胞无明显杀伤效应，0、10、20、40、80和160 μg/ml MOF@siITGAV分别处理4T1细胞24 h，细胞活性分别为（99.7±3.5）%、（98.2±5.2）%、（97.3±6.6）%、（92.1±8.1）%和（92.4±4.1）%。MOF@siITGAV能有效抑制小鼠乳腺癌移植瘤的生长，给药15 d后，空白对照组、MOF@siNC组和MOF@siITGAV组小鼠的肿瘤体积分别为（691.1±193.0）mm3、（652.7±306.5）mm3和（135.3±41.9）mm3，MOF@siITGAV组小鼠的肿瘤体积小于空白对照组（P=0.025）。与空白对照组和MOF@siNC组相比，MOF@siITGAV组小鼠肿瘤组织中Ⅰ型胶原蛋白的含量明显减少，CD8阳性细胞明显增多，心、肝、脾、肺、肾等主要脏器未见明显异常。 结论： ITGAV可以破坏乳腺癌的ECM，改善药物瘤内递送，促进免疫细胞浸润。.