Dooley T P, Wilson R E, Jones N C, Hart I R
Gene Regulation Laboratory, Imperial Cancer Research Fund, Lincoln's Inn Fields, London, UK.
Oncogene. 1988 Nov;3(5):531-5.
We have transfected the polyoma middle T oncogene into an immortal murine melanocyte cell line, Mel-ab. This highly pigmented line is phorbol ester (TPA) dependent for in vitro growth, suggesting activation and/or down regulation of Protein Kinase C (PKC) is essential for mitogenesis. Moreover, cells of this line do not form tumours when injected subcutaneously into immunocompetent or immunoincompetent mice. Here we show that PyMT alone is sufficient to produce TPA-independence and transformation to the tumourigenic state in transfected Mel-ab cells. Western blot analysis shows that middle T overcomes the TPA requirement by a mechanism independent of PKC down regulation though this does appear to occur when Mel-ab cells are grown continuously in TPA. These results suggest that PyMT is not exerting its transforming effect by PKC down regulation, but conceivably at some later stage of second messenger signalling, possibly through PyMT-c-src protein kinase activity.
我们已将多瘤病毒中T癌基因转染到永生小鼠黑素细胞系Mel-ab中。这个色素沉着很深的细胞系在体外生长依赖佛波酯（TPA），这表明蛋白激酶C（PKC）的激活和/或下调对有丝分裂至关重要。此外，将该细胞系的细胞皮下注射到免疫活性或免疫无活性小鼠体内时不会形成肿瘤。在此我们表明，单独的PyMT足以使转染的Mel-ab细胞产生TPA非依赖性并转化为致瘤状态。蛋白质印迹分析表明，中T通过一种独立于PKC下调的机制克服了对TPA的需求，不过当Mel-ab细胞在TPA中连续生长时，PKC下调似乎确实会发生。这些结果表明，PyMT并非通过PKC下调发挥其转化作用，而是可能在第二信使信号传导的某个后期阶段发挥作用，可能是通过PyMT-c-src蛋白激酶活性。
