Role of p21 RAS in p210 bcr-abl transformation of murine myeloid cells.
Role of p21 RAS in p210 bcr-abl transformation of murine myeloid cells.
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DOI：
10.1182/blood.v82.6.1838.bloodjournal8261838
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发表时间：
1993-09
期刊：
影响因子：
20.3
通讯作者：
Romeo A Mandanas;David Leibowitz;K. Gharehbaghi;Tetsuzo Tauchi;G. S. Burgess;K. Miyazawa;H. Jayaram;H. Boswell;Scott Boswell
中科院分区：
文献类型：
--
作者：
Romeo A Mandanas;David Leibowitz;K. Gharehbaghi;Tetsuzo Tauchi;G. S. Burgess;K. Miyazawa;H. Jayaram;H. Boswell;Scott Boswell
P21RAS产物被认为是某些非受体酪氨酸激酶癌基因下游信号的一部分，以及几种生长因子受体-配体相互作用的一部分。我们已经报道了慢性粒细胞白血病癌基因p210 bcr-abl将依赖生长因子的髓系细胞系nsf/n1.H7转化为白细胞介素3(IL-3)非依赖性。在这些p210bcr-abl转化的细胞(H7bcr-abl.A54)和另外两个由p210bcr-abl转化为IL-3独立的小鼠髓系细胞系中，内源性p21RAS被激活，这是由相关的鸟苷三磷酸(GTP)/鸟苷二磷酸(GDP)的比值升高确定的，用Y13-259抗体免疫沉淀后p21RAS洗脱出的核苷酸的薄层层析测定。P210 bcr-abl转化的细胞用特定的酪氨酸激酶抑制剂Herbimycin A处理后，p210 bcr-abl及其相关蛋白的酪氨酸磷酸化程度降低，而p210 bcr-abl蛋白本身的表达没有显著降低。抑制依赖于bcr-abl的p210酪氨酸磷酸化导致转化细胞中活性的p21RAS-GTP复合体减少，核早期反应基因c-jun和c-fos的表达减少，细胞增殖率降低。为了进一步研究p21RAS参与p210BCR-ABL酪氨酸磷酸化下游的这些功能事件，我们通过用肌苷单磷酸脱氢酶抑制剂噻唑呋喃(Tr)限制GTP的可用性，直接针对G蛋白的功能。TR处理p210 bcr-abl转化细胞4h，GTP水平降低50%，而GDP、鸟苷一磷酸和三磷酸腺苷(ATP)未受影响，p210bcr-abl酪氨酸磷酸化水平处于对照水平。但c-fos和c-jun核原癌基因表达受到强烈抑制，p21RAS活性下调。这些发现表明，p210bcr-abl部分通过p21ras下游激活来转导增殖信号。此外，p21RAS活性与调节c-jun和c-fos表达的途径有关。
The p21 RAS product has been implicated as part of the downstream signaling of certain nonreceptor tyrosine kinase oncogenes and several growth factor receptor-ligand interactions. We have reported that the chronic myelogenous leukemia oncogene p210 bcr-abl transforms a growth-factor-dependent myeloid cell line NFS/N1.H7 to interleukin-3 (IL-3) independence. In these p210 bcr-abl-transformed cells (H7 bcr-abl.A54) and in two other murine myeloid cell lines transformed to IL-3 independence by p210 bcr-abl, endogenous p21 RAS is activated as determined by an elevated ratio of associated guanosine triphosphate (GTP)/guanosine diphosphate (GDP), assayed by thin-layer chromatography of the nucleotides eluted from p21 RAS after immunoprecipitation with the Y13-259 antibody. Treatment of p210 bcr-abl-transformed cells with a specific tyrosine kinase inhibitor herbimycin A resulted in diminished tyrosine phosphorylation of p210 bcr-abl and associated proteins, without major reduction in expression of the p210 bcr-abl protein itself. Inhibition of p210 bcr-abl-dependent tyrosine phosphorylation resulted in a reduction of active p21RAS-GTP complexes in the transformed cells, in diminished expression of the nuclear early response genes c-jun and c-fos, and in lower cellular proliferation rate. To further implicate p21 RAS in these functional events downstream of p210 bcr-abl tyrosine phosphorylation, we targeted G-protein function directly by limiting the availability of GTP with the inosine monophosphate dehydrogenase inhibitor, tiazofurin (TR). In p210 bcr-abl-transformed cells treated for 4 hours with TR, in which the levels of GTP were reduced by 50%, but GDP, guanosine monophosphate, and adenosine triphosphate (ATP) were unaffected, p210 bcr-abl tyrosine phosphorylation was at control levels. However, expression of c-fos and c-jun nuclear proto-oncogenes were strongly inhibited and p21 RAS activity was downregulated. These findings show that p210 bcr-abl transduces proliferative signals, in part, through downstream activation of p21 RAS. Furthermore, p21 RAS activity is linked to pathways that regulate c-jun and c-fos expression.