Enhanced therapeutic effect of Adriamycin on multidrug resistant breast cancer by the ABCG2-siRNA loaded polymeric nanoparticles assisted with ultrasound

The overexpression of the breast cancer resistance protein (ABCG2) confers resistance to Adriamycin (ADR) in breast cancer. The silencing of ABCG2 using small interfering RNA (siRNA) could be a promising approach to overcome multidrug resistance (MDR) in cancer cells. To deliver ABCG2-siRNA effectively into breast cancer cells, we used mPEG-PLGA-PLL (PEAL) nanoparticles (NPs) with ultrasound-targeted microbubble destruction (UTMD). PEAL NPs were prepared with an emulsion-solvent evaporation method. The NPs size was about 131.5 ± 6.5 nm. The siRNA stability in serum was enhanced. The intracellular ADR concentration increased after the introduction of siRNA-loaded NPs. After intravenous injection of PEAL NPs in tumor-bearing mice, the ABCG2-siRNA-loaded NPs with UTMD efficiently silenced the ABCG2 gene and enhanced the ADR susceptibility of MCF-7/ADR (ADR resistant human breast cancer cells). The siRNA-loaded NPs with UTMD + ADR showed better tumor inhibition effect and good safety in vivo. These results indicate that ADR-chemotherapy in combination with ABCG2-siRNA is an attractive strategy to treat breast cancer.     

超声靶向微泡破碎联合半乳糖聚乙烯亚胺促凋亡素基因治疗肝癌移植瘤的实验

目的探讨超声靶向微泡破碎(UTMD)联合半乳糖聚乙烯亚胺(PEI-Gal）介导凋亡素基因对小鼠肝癌移植瘤的抑制作用。方法建立c57BL/6小鼠皮下肝癌移植瘤模型,随机分为4组：对照组;PEI-Gal+质粒组;PEI-Gal+超声+质粒组;PEI-Gal+UTMD+质粒组。对组织行冰冻切片采用免疫荧光法检测转染率、Tunel检测凋亡率。观察肿瘤的体积和组织学变化,同时计算抑瘤率。采用免疫组织化学法检测移植瘤Bcl-2及Caspase-3蛋白在各组肿瘤标本中的表达。结果PEI-Gal+UTMD+pEGFP-N3组基因转染效率明显高于对照组、PEI-Gal+质粒组与PEI-Gal+超声+质粒组(P均<0.01）且对组织无明显损伤。治疗12天后PEI-Gal+UTMD+pCDNA-VP3组肿瘤凋亡率(34.57%±3.56%）、抑瘤率(56.6%)均显著高于对照组和PEI-Gal+质粒组(P均<0.01）。肿瘤组织中Bcl-2蛋白表达明显下降,Caspase-3蛋白表达增加与其他各组比较差异均有统计学意义(P<0.01)。结论 超声靶向微泡破碎联合半乳糖聚乙烯亚胺能显著增强基因转染效率,且对组织无明显影响。联合凋亡素基因能通过诱导凋亡抑制肿瘤生长发挥抗瘤作用。