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[摘要]
目的 验证转铁蛋白修饰的β-榄香烯-雷公藤红素共传递微乳(Tf-EC-MEs)协同靶向抗结直肠癌作用。方法 采用四甲基偶氮唑盐(MTT)法检测β-榄香烯、雷公藤红素及联合给药对结直肠癌Lovo细胞和结肠癌HT-29细胞的细胞毒活性,优化最佳质量配比;采用"混匀-滴注"方法制备Tf-EC-MEs,并利用高效液相(HPLC)、激光粒度仪、透射电镜等表征粒子的制剂学及理化性质;采用MTT法、高效液相-二喹啉甲酸(HPLC-BCA)法、膜联蛋白V-PE/7-氨基放线菌素D(Annexin V-PE/7-AAD)试剂盒考察Tf-EC-MEs的体外抗肿瘤活性及对细胞摄取、细胞凋亡的影响;sc Lovo细胞制备荷瘤裸鼠模型,每隔2 d分别iv给予β-榄香烯+雷公藤红素、β-榄香烯-雷公藤红素共传递微乳(EC-MEs)、Tf-EC-MEs,考察Tf-EC-MEs对小鼠肿瘤生长、体质量及生存时间的影响。结果 β-榄香烯-雷公藤红素40:1联合给药对Lovo和HT-29细胞的半数抑制浓度(IC50)分别为(17.5±2.9)、(36.4±3.6)μg/mL,联合指数(CI)分别为0.89和0.96,具有明显的协同抗结直肠癌效应;Tf-EC-MEs对Lovo和HT-29细胞的IC50分别为(11.7±0.6)和(27.4±1.2)μg/mL,CI分别为0.61和0.72。Tf-EC-MEs与Lovo细胞孵育4 h后的摄取量为7.2 μg/mg,是β-榄香烯+雷公藤红素给药组的3.3倍。Tf-EC-MEs能够引发59.2%的Lovo细胞凋亡,显著高于β-榄香烯+雷公藤红素和EC-MEs组。Tf-EC-MEs对荷Lovo大肠癌裸鼠的肿瘤生长抑制率最为明显,且裸鼠60 d后生存率为37.5%。Tf-EC-MEs给药组裸鼠的肿瘤组织HE染色切片出现大量的细胞坏死,Ki-67免疫组化切片显示肿瘤细胞增殖被明显抑制。结论 相较于β-榄香烯+雷公藤红素组和EC-MEs组,Tf-EC-MEs具有更优的协同靶向抗结直肠癌的潜力。
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[Abstract]
Objective To verify the synergistic effect of transferrin modified β-elemene and celastrol co-loaded microemulsion (Tf-EC-MEs) on anti-colorectal cancer treatment. Methods The optimal mass ratio of β-elemene and celastrol to growth inhibition of Lovo and HT-29 colorectal cancer cells was optimized by MTT staining method in vitro. Tf-EC-MEs was prepared by "mixing-dripping" method, and the preparation and physicochemical properties of the particles were characterized by high performance liquid chromatography (HPLC), laser particle analyzer, and transmission electron microscope. The MTT staining, HPLC-BCA combined method, and Annexin V-PE/7-Aminoactinomycin D (Annexin V-PE/7-AAD) kit were used to investigate the antitumor activity of Tf-EC-MEs in vitro, and its effect on cell uptake, and apoptosis of tumor cells. The tumor-bearing nude mice model was established by subcutaneous injection of Lovo cells, and the tumor growth, weight, and survival time were observed after intravenous injection of β-elemene + celastrol, β-elemene-celastrol co-loaded microemulsion (EC-MEs), and Tf-EC-MEs. Results The combined administration of β-elemene and celastrol (40:1) had significant synergistic effect on the anti-colorectal cancer of Lovo and HT-29 cells. IC50 of β-elemene + celastrol in Lovo and HT-29 cells were (17.5 ±2.9) and (36.4 ±3.6) μg/mL, with the CI as 0.89 and 0.96, respectively. IC50 of Tf-EC-MEs in Lovo and HT-29 cells were (11.7 ±0.6) and (27.4 ±1.2) μg/mL, with the CI as 0.61 and 0.72 respectively. The 4 h of Lovo uptake of Tf-EC-MEs was 7.2 μg/mg, which was 3.3 times higher than that of β-elemene + celastrol. Tf-EC-MEs induced apoptosis in 59.2% of Lovo cells, which was significantly higher than that in beta-elemene + celastrol and EC-MEs groups. Tf-EC-MEs showed the overwhelming inhibition of growth of Lovo tumor-bearing tumors. The survival rate of Tf-EC-MEs-treated mice was 37.5% at day 60. In Tf-EC-MEs treated group, HE staining sections of tumor tissues showed substantial cell necrosis and the Ki-67 immunohistochemical sections displayed the significant inhibition of proliferation of tumor cells. Conclusion Compared with the combination group (beta-elemene and celastrol) and EC-MEs groups, Tf-EC-MEs has a promising potential in the synergistic anti-colorectal cancer treatment.
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