磁性吉西他滨隐形纳米脂质体对MCF-7细胞生物学特性的影响

Effects of magnetic gemcitabine stealth nano-liposomes on the characteristics of breast cancer cell line MCF-7

研究磁性吉西他滨隐形纳米脂质体(magnetic gemcitabine stealth nano-liposomes,MGSL)的体内磁响应性及对MCF-7细胞生物学特性的影响。对小鼠头颅部施加磁场,并静脉注射MGSL,通过对脑组织药物含量的分析,研究MGSL在体内的磁响应性;然后在有磁场和无磁场的不同情况下,静脉给予小鼠MGSL,通过对小鼠脑、心、肝、脾、肺及肾等组织的药物含量分析,考察吉西他滨在体内的分布差异,比较磁性靶向作用和单纯给药在组织分布的不同。在体外,观察了MGSL诱导的MCF-7细胞凋亡过程中的细胞形态学改变、MTT法获得MGSL作用乳腺癌细胞生长抑制率、流式细胞仪分析MGSL引起的细胞凋亡率和细胞周期分布。最后制成裸鼠乳腺癌皮下移植瘤模型,通过在移植瘤表面定时给予三维立体梯度磁场作用,观察MGSL靶向治疗裸鼠乳腺癌的效果。低强度磁场组的吉西他滨血药浓度显著高于无磁场组(P<0.01),而高强度磁场组吉西他滨的含量较低强度磁场组显著升高(P<0.01),且当磁场强度达到5000高斯时,吉西他滨含量可达无磁场组的8.5倍。另外应用外加磁场,吉西他滨可以有效聚集到靶部位,显著提高病灶部位吉西他滨的浓度,降低心脏、肾脏等器官的药物浓度。MGSL对人乳腺癌细胞在体外有明显的杀伤作用,其杀伤作用随浓度升高有上升趋势;结果还显示MGSL是主要作用于S期的细胞周期药物;采用流式细胞术证实了MGSL还有促乳腺癌细胞凋亡的作用,其诱导凋亡率达到51.62%。MGSL可以显著抑制裸鼠皮下移植瘤的生长,与其他组别相比均有显著差异(P<0.05)。本法制备的MGSL符合作为纳米磁靶向给药系统的条件,同时它具备较好的磁响应性,在外磁场的作用下可以有效增加肿瘤组织内的药物浓度,而降低正常组织的药物含量,达到靶向化疗的目的,且在体内外显示了较好的抑瘤效应,可望成为一种有效的抗肿瘤制剂。

The magnetic responsibility and antitumor effect of magnetic gemcitabine stealth nano-liposomes （MGSL） on breast cancer cell line MCF-7 in vitro and in vivo was evaluated. The magnetic response and targeting effect of MGSL in vivo were investigated. Morphological feature and ultrastructure changes of apoptosis of MCF-7 cells were observed. The effect of MGSL on proliferation inhibitory rate of MCF-7 cells was measured with MTT method. The FCM analysis was carried out to examine the cell cycle distribution and cell apoptotic rate. The antitumor effect on human breast cancer xenografts in nude mice was also studied. MGSL was able to converge at the targeting tissue under tridimensional magnetic field and the gemcitabine concentration around it increased, while the amount of gemcitabine in other organs decreased, such as in kidneys and heart. MCF-7 cell line was sensitive to MGSL and the cytotoxity was correlated with the loaded drug dose. The effect of MGSL on apoptosis of MCF-7 was obvious and the rate of apoptosis was 51.62%. The growth speed of tumor in the group of MGSL （＋） significantly slowed down than that of other groups. MGSL prepared by reverse-phase evaporation method met with the demand of targeted delivery system, and it might be an effective antitumor agent.