辛伐他汀在裸鼠模型中对乳腺癌骨转移的影响

Effects of simvastatin on human breast cancer osteolytic bone metastasis in a nude mice model

目的 观察辛伐他汀在裸鼠模型中对乳腺癌骨转移的作用.方法采用完全随机分组方法 将60只裸鼠分为3组,每组20只,裸鼠左心腔注射乳腺癌骨转移细胞株（MDA-MB-231）,7d后,分别皮下注射辛伐他汀、生理盐水及无任何处理（2次/周,19 d）.应用图像分析软件评估骨转移瘤的面积.随后处死裸鼠,用放射免疫法检测骨转移癌髓腔内甲状旁腺素相关蛋白（PTHrP）浓度;应用骨密度检测软件进行组织形态学分析,计数骨转移灶每毫米癌组织与临近骨小梁之间破骨细胞的数量.计量资料比较采用方差分析,P＜0.05为差异有统计学意义.结果 与生理盐水组和无处理组相比,注射辛伐他汀的裸鼠骨转移癌面积明显减小（0.51±0.18 mm2 vs 2.13±1.24 mm2 vs 2.29±1.22 mm2;F=15.600,P=0.002; F=15.673,P=0.001）,骨转移癌周围髓腔内PTHrP浓度明显降低（0.98±0.20 pmol/L vs 2.11±0.31 pmol/L vs 1.99±0.29 pmol/L;F=61.469,P＜0.001;F=58.274,P＜0.001）,并且其转移灶破骨细胞的数量明显减少（4.00±1.73个/mm vs 11.40 ±4.93个/mm vs 10.91±3.87个/mm;F=17.820,P=0.001,F=17.184,P=0.002）.结论 辛伐他汀能够降低乳腺癌细胞PTHrP的分泌,从而抑制乳腺癌细胞在骨内生长及其对骨质的破坏.

Objective To observe the effect of simvastatin on bone metastasis of breast cancer in nude mice model.Methods Sixty mice were divided into three groups randomly with 20 in each group.Mice were inoculated with MDA-MB-231 cells into the left cardiac ventricle.After 7 days,mice were treated with either simvastatin,saline,or nothing twice per week for 19 days.The area of osteolytic metastases was subsequently measured in long bones of all mice using an image analysis system.After sacrifice,parathyroid hormone-related protein （PTHrP） concentrations in bone marrow from all mice were determined using a two-site immunoradiometric assay.Osteoclast number expressed per millimeter of tumor/bone interface was assessed using an OsteoMeasure System.Measured data were compared with analysis of variance,and P ＜ 0.05 for the difference was statistically significant.Results The area of osteolytic lesions was significantly lower in mice treated with simvastatin compared with mice receiving saline and no treatment （0.51 ±0.18 mm2 vs 2.13 ± 1.24 mm2 vs 2.29 ± 1.22 mm2 ; F =15.600,P =0.002 ; F =15.673,P =0.001）.In addition,treatment with simvastatin decreased the concentrations of PTHrP in bone marrow plasma （0.98 ±0.20 pmol/L vs 2.11 ±0.31 pmoL/L vs 1.99 ± 0.29 pmol/L; F =61.469,P ＜ 0.001 ; F =58.274,P ＜ 0.001） and the osteoclast numbers per millimeter of tumor/bone interface （4.00 ± 1.73 vs 11.40 ±4.93 vs 10.91 ± 3.87 ; F =17.820,P =0.001 ; F =17.184,P =0.002） compared with controls.Conclusion Simvastatin may reduce the production of PTHrP of breast cancer cells,which suppresses the development of destructive bone lesions as well as the growth of breast cancer cells in bone.