The role of sclerostin antibody in treatment of bone metastasis from breast cancer

目的 观察用骨硬化蛋白抗体拮抗肿瘤细胞骨硬化蛋白(sclerostin)功能对乳腺癌MDA-MB-231细胞骨转移能力的影响.方法 骨硬化蛋白单链抗体(Sci-Ab)和MDA-MB-231细胞共培养,观察细胞侵袭和迁移能力的改变.24只6～8周龄雌性裸鼠被随机分为两组,每组12只,每只裸鼠分别以5×106个MDA-MB-231细胞注射入左侧股骨骨髓腔.对照组注射生理盐水治疗,实验组给予骨硬化蛋白抗体(Sci-Ab)治疗,35 d后行病理检查,比较两组骨转移发生率和骨肿瘤体积大小.取小鼠股骨,经micro-CT扫描并三维重构,观察各组小鼠骨破坏情况.定量资料的比较采用t检验,定性资料比较采用Fisher确切概率检验.结果 MTT实验和划痕实验表明,高浓度的Sci-Ab促进MDA-MB-231增值和侵袭(P＜0.05).对照组有6只发生骨转移,治疗组有9只发生骨转移.治疗组的骨转移发生率虽高于对照组,但两者差异无统计学意义(P=0.30).对照组肿瘤平均体积为(0.87±0.244) cm3,治疗组肿瘤平均体积为(0.73 ±0.118) cm3,两组间差异无统计学意义(P=0.35).治疗组的生存率高于对照组,有统计学差异(P＜0.05).Micro-CT分析表明,骨硬化蛋白抗体治疗能够阻止乳腺癌导致的骨损伤并且骨密度高于对照组,两组间差异有统计学意义(P＜0.05).结论 乳腺癌细胞致骨转移能力与骨硬化蛋白表达水平密切相关,抑制骨硬化蛋白表达可以提高乳腺癌细胞致骨转移的能力,但是能够提高乳腺癌骨转移模型小鼠的生存率,生存率的提高可能与阻止乳腺癌骨转移所介导的骨破坏相关.Objective To investigate the impact of inhibiting the function of sclerostin by antibodies in tumor cells on MDAMB-231 induced bone metastasis.Methods MDA-MB-231 cells were co-cultured with sclerostin antibody(Sci-Ab).Twenty-four female nude mice aged 6-8 weeks were divided randomly into two groups (n =12).MDA-MB-231 cells (6 × 105) were injected into the bone marrow space.The mice were treated with normal saline (NS) and sclerostin antibody (Sci-Ab),respectively.Thirty-five days after the treatment,all the nude mice were subjected to pathological examination to determine bone metastasis.The bone remodelling activities were compared between PBS treatment group and antibody treatment group using micro-CT analysis.Student's t-test was used for the comparison of quantitative data,and Fisher's exact test was used for the comparison of qualitative data.Results According to MTT assay and Wound Healing,higher Sci-Ab promoted the proliferation and invasion of MDA-MB-231 cells.There were six bone metastasis lesions detected in control group(treated with normal saline),and nine in experimental group(treated with Sci-Ab),but there was no statistically significant difference between the two groups(P =0.30).The bone tumor volume of control group and experimental group was (0.87 ± 0.244) cm3 and (0.73 ± 0.118) cm3,respectively (P =0.35).The survival of experimental group was significantly longer than that of control group(P ＜ 0.05).Micro-CT analysis of the tumor-bearing mice indicated that Sci-Ab was effective in bone protection against breast cancer-induced bone destruction as the bone mineral density (BMD;g/cm2) was significantly increased (P ＜ 0.05).Conclusions Bone metastasis from breast cancer is closely correlated with the sclerostin expression level in tumor cells.Inhibiting the expression of sclerostin can promote proliferation and invasion of MDA-MB-231 cells in vitro and improve the survival of mice in vivo.北京市科学技术委员会基金; 中国医师协会6609-613,6162