马钱子碱经皮给药对乳腺癌骨转移抑制机制的探讨

Inhibition effect of brucine percutaneous administration on bone metastasis in breast cancer

目的:探讨马钱子碱经皮给药对乳腺癌骨转移的抑制机制,为乳腺癌的治疗提供新的途径。方法:培养人乳腺癌细胞株MDA-MB-231,取对数生长期细胞制成单细胞悬液。20只雌性Balb/c-nu/nu裸鼠麻醉后,无菌条件下,局部骨内注射乳腺癌单细胞悬液0.2mL,复制乳腺癌骨转移模型。20只荷瘤裸鼠随机分为马钱子碱高剂量组、中剂量组、低剂量组和模型组4组,分别给予20%(0.2mg/g)、10%(0.1mg/g)和5%(0.05mg/g)浓度的马钱子碱膏(每日总剂量≤腹腔给药的半数致死量)和凡士林经皮给药,涂抹裸鼠的整个腹部和造模的部位,1g/次,4次/d(每次间隔3h),连续15d。影像学观察骨转移情况;RT-PCR检测并比较各组肿瘤组织中,骨转移相关因子VEGF、COX-2和PTHrP的表达量。结果:胫骨的X射线表现,马钱子碱高剂量组和中剂量组的骨质破坏不明显,低剂量组和模型组的骨质破坏明显,甚至出现病理性骨折。RT-PCR结果显示,钱子碱高剂量组VEGF、COX-2和PTHrP mRNA的表达分别为25.30±0.90、20.63±0.73和25.56±0.54,马钱子碱中剂量组分别为24.10±0.73、20.49±0.76和25.74±0.48,马钱子碱低剂量组分别为25.27±0.75、21.02±0.65和25.65±0.44,模型组分别为24.09±0.74、21.14±0.66和25.75±0.39。与模型组比较,马钱子碱各剂量组VEGF、COX-2和PTHrP mRNA的表达量随着马钱子碱剂量的增加逐渐下降,差异均有统计学意义,P<0.05。结论:马钱子碱经皮给药能抑制裸鼠乳腺癌骨转移瘤的生长,减轻骨损伤,其机制可能是通过调控VEGF、COX-2和PTHrP的表达而抑制乳腺癌骨转移瘤的生长。

OBJECTIVE：To construct a model of nude mice breast cancer osseous metastasis and observe the inhibi tory action of nude mice breast cancer osseous metastasis through brucine transdermal drug delivery. By using RT-PCR method to analyze the influence of brucine transdermal drug delivery to the expression level of correlation factors such as VEGF,COX-2 and PTHrP,and to discuss its mechanism. METHODS： Foster breast cancer cell line MDA-MB-231 were prepared and 20 female Balb/c-nu/nu nude mice were intraosseously injected the breast cancer cell 0.2 mL under anaesthe sia. The model of breast cancer osseous metastasis were duplicaled. Twenty nude mice were divided into four groups ran domly,Brucine high dose group（A）,middle dose group（B）,low dose group（C） and model group（D） and in this order to give them brucine 20 % （0.2 mg/g）, 10 ± （0.1 mg/g）, 5 % （0.05 mg/g）, （based on median lethal dose through intraperito- neal） and Vaseline transdermal drug delivery four times each day for 2 weeks. RT-PCR detection was used to compare the expression levels of osseous metastasis correlation factors：VEGF,COX-2,PTHrP. RESULTS：The X ray of tibia demon- strated that the sclerotin destroy of those mice from Group A containing high dose of brucine,and group B containing mid- dle dose of brucine was not obvious. However, those mice from group C and group D had a significant sclerotindestroy, even pathologic fracture. RT-PCR results = VEGF, COX2 and PTHrP ： Group A was 25.30 ± 0.90,20.63 ± 0.73 and 25.56±0.54. Group B was 24.10±0. 73,20. 49±0. 76 and 25.74±0.48. Group C was 25. 27±0. 75,21. 02±0. 65 and 25.65±0.44. Group D was 24. 094±0.74,21.14±0.66 and 25.75±0.39. The results showed that mRNA quantity of VEGF,COX-2 and PTHrP were down-regulated with dose of brucine, comparing to the control group（P〈0.05）. CONCLUSIONS： Brucine transdermal drug delivery can restrain the growth of nude mice breast cancer osseous metastasis, relieve bone damage. The mechanism may be restraining breast cancer osseous metastasis through regulating and control- ling the expressions of those correlation factors like VEGF,COX-2 and PTHrP.