不同接种量荧光素酶标记小鼠乳腺癌细胞4T1在小鼠体内生长及肺转移的比较

Comparison of the tumor growth and pulmonary metastasis in mice transplanted with different number of luciferase-labeled mouse breast cancer 4T1 cells

目的采用活体成像技术比较四种剂量荧光素酶标记肿瘤细胞在小鼠体内生长及肺转移情况,为光学标记肿瘤模型的药物筛选或机制研究提供参考资料。方法以荧光素酶作为报告基因导入小鼠乳腺癌细胞4T1中,经G418筛选获得稳定表达荧光素酶的细胞克隆并扩大培养。标记细胞稀释成1×107细胞/mL,2×107细胞/mL,5×107细胞/mL和1×108细胞/mL四种剂量,取0.1 mL接种于BALB/c小鼠右侧第二对乳腺脂肪垫内,制作小鼠原位乳腺癌模型,比较肿瘤细胞在小鼠体内生长及肺转移情况。结果获得稳定表达荧光素酶基因的细胞克隆,在致瘤性方面和亲代细胞无明显差别,四种剂量细胞接种BALB/c小鼠后,均有肿瘤生长,接种第28天时,四种剂量接种的原位移植瘤大小没有明显差别,但接种两个高剂量肿瘤细胞的小鼠组各有2只小鼠死亡;接种后31 d,发现四种剂量接种的原位移植瘤均发生不同程度的转移,随着观察天数的增加,转移程度逐渐严重,接种后42 d,小鼠陆续发生死亡。结论根据转移和死亡情况,确定接种1×106个细胞/只不仅肺转移明显,而且存活时间一般超过45 d,比高剂量接种存活时间长,为最佳肺转移剂量。

Objective To study the tumor growth and pulmonary metastasis in mice transplanted with different number of luciferase-labeled mouse breast cancer cells, and to provide important information for drug screening and cancer mechanism research. Methods The vector containing luciferase gene was constructed and transfected into mouse breast tumor cell line 4T1 cells and selected with C,418 to obtain stable Lue-expressing clones. The cells in logarithmic phase was collected and diluted to 1 x 10s , 5 x 107 , 2 x 107 and 1 x 107 cells/mL. Then 0.1 mL cell suspension was inoculated into the second mammary fat pad on the right side of normal BALB/c mice to establish the tumor models. Their tumorigenesis and metastasis were analyzed in vivo. Results The stable Luc-expressing cell lines were obtained which had no obvious difference with parental cells in tumorigenicity. The whole-body optical imaging found that tumor could be formed after the cells were inoculated orthotopically. After 28 days, the tumor sizes were similar among the four concentrations, while therewere two mice each died at 5 ~ 106 and 1 x 107 cells concentrations. After 31 days, the tumor metastasis showed different degree among the four concentrations. The metastasis became more seriously with time passed. However, after 42 days, deaths of mice occurred in succession. Conclusions The number of 1 x 10s cells is the best concentration, not only induces obvious pulmonary metastasis but also shows a survival time longer than 45 days, compared with that induced at other higher concentrations.