肿瘤干细胞表型CD44和CD24在乳腺癌骨转移模型骨髓中的表达及意义

目的 探讨人乳腺癌细胞转移到人骨的乳腺癌骨转移小鼠模型中骨髓肿瘤干细胞表型CD44和CD24的表达及其意义.方法 50只SCID小鼠随机分成实验组和对照组,其中实验组鼠背部植入人骨后随机均分3亚组:A组(MDA-MB-231干细胞亚群1×105个/只)、B组(同A组细胞1×106个/只)和C组(MDA-MB-231亲代细胞1×106个/只);对照组设为D组(阳性对照,未植入人骨,同C组细胞直接注射)、E组(阴性对照,植入人骨,生理盐水注射).各组8周后取人骨、鼠骨等行常规HE染色及CK、CD44、CD24、CXCR4、OPN免疫组织化学标记.Real-time PCR检测CD44、CXCR4、OPN的mRNA水平.结果 B组骨转移率最高(77.8%,P＜0.05).B组中人骨转移灶CD44、CXCR4、OPN抗原表达高于C、D组骨中的表达(均有P＜0.05);CD24抗原则在A、B组人骨转移灶中低表达与C、D组骨中的高表达无统计学意义(P＞0.05).B组CD44mRNA表达水平是C组的15.2倍、D组的21.1倍;B组CXCR4mRNA表达水平是C组8.4倍、D组28.4倍;B组OPN-mRNA表达水平是C组4.8倍、D组11.6倍;而B组CD24的mRNA表达显著低于C、D组(均为30%).结论 利用MDA-MB-231肿瘤干细胞亚群(CD44+/CD24-)可制备高转移率的"人源性"乳腺癌骨转移模型,其机制可能与CD44高表达有关.骨转移相关基因CXCR4、OPN转录上调可能参与其过程.

The expression of breast cancer stem cell phenotype of CD44+/CD24-in a mouse model of human breast cancer metastasis to implanted human bone

Objective To investigate the expression and significance of breast cancer stem cell phenotype of CD44+/CD24-in a mouse model of human breast cancer metastasis to implanted human bone by inieeting human breast cancer cells into the left cardiac ventricle in severe combined immunodeficient(SCID/berg)female mice.Methods 50 SCID/berg female mice with 4-to 5-week old were randomly divided into experimental(n=30)and control group(n=20)Then the experimental group had human bone implanted into right or left dorsal flanks and were divided into group A,B,CAnimals in Group A,B,C were respectively injcoted with 1×105,1×106human breast cancer stem-like cells,and 1×106parental MDA-MB-231 cells.A positive control group(D)without implantation of human bone was also iniected with 1×106MDA-MB-231 parental cells.A group of negative controls(E)with implantation of human bone was injected with isotonie sodium chloride.All anitaals were sacrificed at week 8..Immunohistochemistry was performed for CK,CD44,CD24,CXCR4,and OPN.Results bone metastatic morbidity in group B was highest among all groups(77.8%,P＜0.05).The expression of CD44,CXCR4,OPN in bone metastasis tissues were stronger in group B than that of group C,D(P＜0.05).The real time PCR showed there was a increase of CD44 mRNA in metastatic bone tissues in group B eompared with that of group C and D(15.2-fold and 21.1-fold,respectively).The mRNA levels of CXCR4,OPN in bone metastasis tissues of group B were all higher than that of group C and D(8.4-fold,28.4-fold;4.8-fold,11.6-fold;respectively).Wllile the levels of CD24 mRNA in group B was lowest,only being 30 percent of that in group C and D.Conelusion MDA-MB-231 cancer stem-like cells can be used to build a model of breast cancer metastasis with a high morbidity of metastasis to implanted human bone.Its mechanism is related to highexpression of CD44.And CXCR4 and OPN are involved in the process.