高表达HER2的自发转移性乳腺癌小鼠模型的建立与应用

摘要

Aim To establish a mouse breast cancer model stab-ly expressing HER2. Methods 4T1-Luc mouse breast cancer cell line was transfected with the full-length human HER2 gene and selected with G418. The HER2 expression in 4T1-Luc stable cells was detected by fluorescence-activated cell sorting ( FACS) and Western blot. 4T1-Luc/HER2 cells were implanted into the mammary fat pads of BALB/c or nude mice. After tumor stabili-zation, mice were randomly assigned into 4 groups for treatment with PBS control, chA21, Trastuzumab, or chA21 plus Trastu-zumab. Tumor volumes were measured and tumor growth inhibi-tion ratios were calculated twice a week. At the end of experi-ment, tumor metastasis in mice was detected by bioluminescence imaging technology. Results Several 4T1-Luc/HER2 stable cell clones were obtained after G418 selection. FACS and West-ern blot analysis showed that all clones expressed HER2 protein at high levels. These 4T1-Luc/HER2 clones showed good tumor-igenicity in mice with steady tumor growth after one week of cell implantation. After 2-3 weeks, metastatic tumor cells were seen in the lung, cheek and groin areas. In BALB/c mice, the tumor growth inhibition ratio was 43. 3% in chA21 plus Trastuzumab group (P<0. 05 vs PBS control), which was higher than chA21 group (11. 1%) or Trastuzumab group (23%). In addition, the luminescence number and density of tumor metastases in lungs were significantly reduced in the antibody combination group. Conclusions The mouse model of spontaneously metastasizing breast cancer with HER2 overexpression is successfully estab-lished. The preliminary study suggests that anti-HER2 antibody combination of chA21 and Trastuzumab has excellent inhibitory effects on tumor growth and metastasis.%目的：建立高表达HER2的自发转移性乳腺癌小鼠移植瘤模型,用于抗HER2抗体等靶向药物的药效学活性和作用机制研究。方法将重组HER2全长基因转染含有荧光素酶基因的小鼠乳腺癌细胞系4T1-Luc,用G418加压筛选,采用流式细胞术和免疫印迹方法鉴定4T1-Luc稳转细胞株中HER2表达。将细胞注射BALB/c小鼠或裸鼠皮下乳房垫,待肿瘤生长稳定后随机分为4组给药,即 PBS 对照、chA21、Trastuzumab 和抗体联合组。每周2次测量肿瘤体积,并计算抑瘤率。实验结束时用活体动物成像仪监测体内肿瘤转移情况。结果经过 G418筛选获得了多个4T1-Luc/HER2稳转细胞株克隆,流式细胞术和免疫印迹均证实HER2高表达。这些克隆均具有良好的成瘤性,细胞注射1周后可见肿瘤稳定生长,2~3周后可观察到肿瘤转移到肺、面部、腹股沟等部位。在BALB/c小鼠中,抗体联合组抑瘤率达43．3%,与 PBS 对照组之间的差异有显著性( P <0．05),并且明显优于抗体单用组抑瘤率( chA21组为11．1%,Trastuzumab 组为23%)。而且,抗体联合组在小鼠肺部的肿瘤转移灶的数目和荧光强度与对照组相比明显降低。结论成功构建高表达HER2的4T1-Luc乳腺癌细胞系并建立自发转移性乳腺癌小鼠模型。初步研究结果表明抗HER2抗体chA21与Trastuzumab联合使用具有良好的抗肿瘤生长和转移的作用。