Guo X Y, Balague C, Wang T, Randhawa G, Yuan Z, Bachier C, Greenberger J, Arlinghaus R, Kufe D, Deisseroth A B
Department of Internal Medicine, Yale Cancer Center, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Oncogene. 1999 Feb 25;18(8):1589-95. doi: 10.1038/sj.onc.1202479.
In order to test if the carboxyl terminal polypeptide of the Retinoblastoma (Rb) tumor suppressor protein, could be used to suppress the growth factor-independent growth phenotype of p210bcr-abl positive myeloid cells, we introduced a truncated form of the 3' end of the Rb cDNA encoding its last 173 amino acid residues (Rb C-box) which localize into the cytoplasm where the p210bcr-abl transforming protein is found, into myeloid cells (32D) which depends on the p210bcr-abl protein for IL3 growth factor-independent growth (32D-p210). The expression of the plasmid vectors carrying the Rb C-box cDNAs was shown to inhibit the abl tyrosine specific protein kinase activity of the p210(bcr-abl) oncoprotein and to suppress the IL3-independent growth phenotype of the 32D-p210 cells. The Rb C-box polypeptides did not suppress the growth of the untransfected 32D parental cell line in methylcellulose in the presence of IL3-conditioned medium. These results suggest that the cytoplasmic localization of the p210(bcr-abl) allows it to escape the effect of intranuclear proteins such as Rb which negatively regulate the p145(c-abl) kinase.
为了检测视网膜母细胞瘤（Rb）肿瘤抑制蛋白的羧基末端多肽是否可用于抑制p210bcr-abl阳性髓系细胞的生长因子非依赖性生长表型，我们将编码Rb最后173个氨基酸残基（Rb C盒）的Rb cDNA 3'端截短形式导入髓系细胞（32D），该截短形式定位于发现p210bcr-abl转化蛋白的细胞质中，而32D细胞依赖p210bcr-abl蛋白实现白细胞介素3（IL3）生长因子非依赖性生长（32D-p210）。携带Rb C盒cDNA的质粒载体的表达被证明可抑制p210（bcr-abl）癌蛋白的abl酪氨酸特异性蛋白激酶活性，并抑制32D-p210细胞的IL3非依赖性生长表型。在IL3条件培养基存在下，Rb C盒多肽在甲基纤维素中并未抑制未转染的32D亲本细胞系的生长。这些结果表明，p210（bcr-abl）的细胞质定位使其能够逃避如Rb等细胞核内蛋白的作用，Rb可负向调节p145（c-abl）激酶。
