Calorini L, Marozzi A, Byers H R, Waneck G L, Lee K W, Isselbacher K J, Gattoni-Celli S
Department of Radiation Oncology, New England Medical Center, Boston, Massachusetts 02111.
Cancer Res. 1992 Jul 15;52(14):4036-41.
In vivo experiments performed with NIH (nu/nu, bg/bg, xid/xid) triple immunodeficient (TD) mice revealed the striking ability of i.v. injected B16-F1 and B16-F10 murine melanoma cells to colonize not only the lungs but also the liver of TD mice. Subsequently, B16 melanoma cell cultures, which express very low levels of H-2Kb antigen, were cotransfected with plasmids pRSVneo, containing the neomycin resistance gene, and 6-2B1pMT, expressing the H-2Kb complentary DNA under the control of the metallothionein enhancer-promoter. Several neomycin-resistant clones were analyzed for H-2Kb and H-2Db expression by RNase protection and flow cytometry assays. All parental lines and transfected clones expressed normal levels of H-2Db mRNA, while only some of the transfected clones expressed easily detectable levels of H-2Kb mRNA. Moreover, in these clones H-2Kb expression could be enhanced in the presence of Zn2+, indicating that the metallothionein enhancer was functioning properly. Parental cells and transfected clones were injected i.v. in TD mice to assess the possible involvement of H-2Kb antigen in regulating the metastatic potential of B16 melanoma cells. We observed a remarkable correlation between expression of H-2Kb antigen and suppression of liver-specific metastases in TD mice. Identical results were obtained when we gave TD mice injections of mixed populations of transfectants expressing H-2Kb antigen, obtained by fluorescence-activated cell sorting. These experiments allowed us to rule out the possibility that the observed changes in metastatic potential were due to clonal variability among individual transfected clones. Taken together, the results of our in vivo studies with immunodeficient mice support the notion that specific major histocompatibility complex Class I molecules modulate the metastatic potential of malignant cells also by mechanisms which are independent of their well-established role in antigen presentation.
对NIH（nu/nu、bg/bg、xid/xid）三重免疫缺陷（TD）小鼠进行的体内实验表明，静脉注射的B16-F1和B16-F10小鼠黑色素瘤细胞不仅具有在TD小鼠肺部定植的显著能力，还能在其肝脏中定植。随后，将表达极低水平H-2Kb抗原的B16黑色素瘤细胞培养物与含有新霉素抗性基因的质粒pRSVneo以及在金属硫蛋白增强子-启动子控制下表达H-2Kb互补DNA的6-2B1pMT共转染。通过核糖核酸酶保护和流式细胞术分析了几个新霉素抗性克隆的H-2Kb和H-2Db表达情况。所有亲代细胞系和转染克隆均表达正常水平的H-2Db mRNA，而只有一些转染克隆表达易于检测水平的H-2Kb mRNA。此外，在这些克隆中，H-2Kb表达在Zn2+存在的情况下可以增强，这表明金属硫蛋白增强子功能正常。将亲代细胞和转染克隆静脉注射到TD小鼠体内，以评估H-2Kb抗原在调节B16黑色素瘤细胞转移潜能中的可能作用。我们观察到TD小鼠中H-2Kb抗原的表达与肝脏特异性转移的抑制之间存在显著相关性。当我们给TD小鼠注射通过荧光激活细胞分选获得的表达H-2Kb抗原的转染细胞混合群体时，也得到了相同的结果。这些实验使我们能够排除观察到的转移潜能变化是由于各个转染克隆之间的克隆变异性这一可能性。综上所述，我们对免疫缺陷小鼠进行的体内研究结果支持这样一种观点，即特定的主要组织相容性复合体I类分子还通过与其在抗原呈递中已确立的作用无关的机制来调节恶性细胞的转移潜能。
