RGD和TAT共修饰紫杉醇脂质体的构建及其体外抗肿瘤研究

目的：制备三肽序列精氨酸-甘氨酸-天冬氨酸(Arg-Gly-Asp，RGD)和细胞穿膜肽TAT共修饰紫杉醇(PTX)脂 质体(RGD/TAT-LP-PTX)，对其理化性质进行表征，并研究脂质体与乳腺癌MCF-7细胞的亲和力和增殖抑制作用。方 法：采用薄膜分散法制备RGD/TAT-LP-PTX，考察脂质体的粒径、电位以及包封率；通过定量细胞摄取实验研究乳 腺癌MCF-7细胞对RGD/TAT-LP的摄取效率以及脂质体的摄取机制。定性共聚焦实验观察肿瘤细胞对脂质体的摄取。 MTT实验研究RGD/TAT-LP-PTX对乳腺癌MCF-7细胞的细胞毒性；构建乳腺癌MCF-7细胞肿瘤球模型，研究脂质体对 肿瘤球的穿透能力。结果：RGD/TAT-LP-PTX的粒径为(138.8±12.4) nm，电位为(25.85±2.75) mV，紫杉醇的包封率为 88.3%。细胞摄取实验结果显示：RGD/TAT-LP在孵育4 h时的摄取效率是2 h的1.79倍(P<0.05)；乳腺癌MCF-7细胞在 与脂质体共同孵育4 h后对RGD/TAT-LP的摄取效率分别是TAT-LP，RGD-LP和LP的2.25倍、2.72倍和4.58倍(P<0.01)； RGD/TAT-LP-PTX对乳腺癌MCF-7细胞的增殖抑制率随时间的延长而增长，RGD/TAT-LP-PTX在孵育48 h时对乳腺癌 MCF-7细胞的抑制率是24 h的1.78倍(P<0.05)；在给予RGD/TAT-LP-PTX，TAT-LP-PTX，RGD-LP-PTX和LP-PTX四种 脂质体药物48 h后，RGD/TAT-LP-PTX组的抑制率是TAT-LP-PTX，RGD-LP-PTX和LP-PTX的1.65倍、1.82倍和2.55倍 (P<0.01)。RGD/TAT-LP对肿瘤球的穿透能力明显强于其他脂质体。结论：RGD和细胞穿膜肽TAT共修饰PTX脂质体能 够有效识别并穿透肿瘤细胞膜进入肿瘤细胞，是一种潜在高效的乳腺癌给药系统。

Preparation and evaluation of RGD and TAT co-modified paclitaxel loaded liposome

Objective: To prepare Arg-Gly-Asp (RGD) and cell penetrating peptide TAT co-modified paclitaxel loaded liposome (RGD/TAT-LP-PTX) for MCF-7 cell inhibition. Methods: The co-modified liposome was prepared by film-ultrasonic method. The appearance, particle size and zeta potential were evaluated. The cellular uptake by MCF-7 cells in vitro was used to evaluate the targeting efficiency. The anti-proliferation efficiency of RGD/TAT-LP-PTX was evaluated by MTT assay. Tumor spheroids were used to evaluate anti-tumor ability of RGD/TAT-LP-PTX in vitro. Results: The particle diameter of the co-modified liposome was (138.8±12.4) nm with the Zeta potential of (25.85±2.75) mV. The entrapment efficiency of PTX was 88.3%. The RGD/TAT-LP uptaken by MCF-7 cells at 4 h was 1.79 times higher than that at 2 h. The co-modified liposome uptaken by MCF-7 cells was 2.25 and 2.72 times higher than that of TAT-LP and RGD-LP, respectively. The anti-proliferation rate of RGD/TAT-LP-PTX increased with time. The inhibition rate of RGD/TAT-LP-PTX for MCF-7 cells at 48 h was 1.78 times higher than that at 24 h. The MTT assay demonstrated the cell viability of RGD/TAT-LP-PTX was 1.65, 1.82 and 2.55 times higher than that of TAT-LP-PTX, RGD-LP-PTX and LP-PTX, respectively. Conclusion: Co-modified liposome may serve as a promising breast cancer delivery system for antitumor drugs.