Du Zhijun, Podsypanina Katrina, Huang Shixia, McGrath Amanda, Toneff Michael J, Bogoslovskaia Ekaterina, Zhang Xiaomei, Moraes Ricardo C, Fluck Michele, Allred D Craig, Lewis Michael T, Varmus Harold E, Li Yi
Breast Center, Baylor College of Medicine, Houston, TX 77030, USA.
Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17396-401. doi: 10.1073/pnas.0608607103. Epub 2006 Nov 7.
We have adapted the avian leukosis virus RCAS (replication-competent avian sarcoma-leukosis virus LTR splice acceptor)-mediated somatic gene transfer technique to introduce oncogenes into mammary cells in mice transgenic for the avian subgroup A receptor gene, tva, under control of the mouse mammary tumor virus (MMTV) promoter. Intraductal instillation of an RCAS vector carrying the polyoma middle T antigen (PyMT) gene (RCAS-PyMT) induced multiple, oligoclonal tumors within 3 weeks in infected mammary glands of MMTV-tva transgenic mice. The rapid appearance of these tumors from a relatively small pool of infected cells (estimated to be approximately 2 x 10(3) cells per gland by infection with RCAS carrying a GFP gene; RCAS-GFP) was accompanied by a high fraction of cells positive for Ki67, Cyclin D1, and c-Myc, implying strong proliferation competence. Furthermore, the tumors displayed greater cellular heterogeneity than did tumors arising in MMTV-PyMT mice, suggesting that RCAS-PyMT transforms a relatively immature cell type. Infection of mice transgenic for both MMTV-Wnt-1 and MMTV-tva with RCAS virus carrying an activated Neu oncogene dramatically enhanced tumor formation over what is observed in uninfected bitransgenic animals. We conclude that infection of mammary glands with retrovirus vectors is an efficient means to screen candidate oncogenes for their capacity to initiate or promote mammary carcinogenesis in the mouse.
我们采用了禽白血病病毒RCAS（具有复制能力的禽肉瘤-白血病病毒LTR剪接受体）介导的体细胞基因转移技术，将癌基因导入在小鼠乳腺肿瘤病毒（MMTV）启动子控制下、转染了禽A亚群受体基因tva的小鼠乳腺细胞中。经导管滴注携带多瘤病毒中T抗原（PyMT）基因的RCAS载体（RCAS-PyMT），在MMTV-tva转基因小鼠受感染的乳腺中，3周内诱发了多个寡克隆肿瘤。这些肿瘤从相对少量的感染细胞（通过感染携带绿色荧光蛋白基因的RCAS估计每个腺体约为2×10³个细胞；RCAS-GFP）中迅速出现，同时伴有高比例的Ki67、细胞周期蛋白D1和c-Myc阳性细胞，这意味着其具有很强的增殖能力。此外，与MMTV-PyMT小鼠产生的肿瘤相比，这些肿瘤表现出更大的细胞异质性，表明RCAS-PyMT转化的是一种相对不成熟的细胞类型。用携带激活型Neu癌基因的RCAS病毒感染同时转染了MMTV-Wnt-1和MMTV-tva的转基因小鼠，与未感染的双转基因动物相比，显著增强了肿瘤形成。我们得出结论，用逆转录病毒载体感染乳腺是筛选候选癌基因在小鼠中启动或促进乳腺癌发生能力的有效方法。
