Ahmed M, Dusanter-Fourt I, Bernard M, Mayeux P, Hawley R G, Bennardo T, Novault S, Bonnet M L, Gisselbrecht S, Varet B, Turhan A G
CNRS-URA 1461, Paris, France.
Oncogene. 1998 Jan 29;16(4):489-96. doi: 10.1038/sj.onc.1201556.
The interleukin-3 dependent murine Ba/F3 cell line has been widely used as an experimental model of cell transformation by BCR-ABL oncogenes as assessed by induction of growth-factor-independence and inhibition of apoptosis in vitro. The signaling pathways used by BCR-ABL oncogenes to exert these effects are unknown. To gain insights into this phenomenon, we have introduced the p190- and p210-encoding BCR-ABL oncogenes as well as the constitutively activated oncogenic murine erythropoietin receptor (cEpoR) into Ba/F3 and compared the behavior of individual clones in response to apoptotic stimuli. Both p210 and p190 BCR-ABL vectors induced IL-3-independent growth and the same result was obtained with the cEpo-R vector. Individual clones of Ba/F3 cells expressing BCR-ABL exhibited significant resistance to apoptosis induced by either etoposide, serum deprivation or growth-factor withdrawal. In contrast, Ba/F3 cells expressing the constitutively active cEpoR behaved like parental Ba/F3 cells undergoing apoptosis when similarly treated with etoposide or upon serum deprivation. Bc12 and Bax levels were similar in all BCR-ABL and cEpoR-transfected clones. However, in band-shift assays, nuclear extracts from growth-factor-independent Ba/F3 clones expressing cEpoR had no detectable STAT activity as opposed to the constitutive STAT activation detected in all Ba/F3 clones expressing p210 or p190 BCR-ABL. Our results indicate that although both constitutively activated cEpoR and BCR-ABL oncogenes induce growth-factor independence in Ba/F3 cells, only BCR-ABL is able to protect cells from etoposide and serum-deprivation-induced apoptosis and induce a strong constitutive activation of STAT factors, suggesting a role for these molecules in the anti-apoptotic activity of BCR-ABL.
白细胞介素-3依赖的小鼠Ba/F3细胞系已被广泛用作BCR-ABL癌基因细胞转化的实验模型，这是通过体外诱导生长因子非依赖性和抑制细胞凋亡来评估的。BCR-ABL癌基因发挥这些作用所使用的信号通路尚不清楚。为了深入了解这一现象，我们将编码p190和p210的BCR-ABL癌基因以及组成型激活的致癌性小鼠促红细胞生成素受体（cEpoR）导入Ba/F3细胞，并比较了各个克隆对凋亡刺激的反应行为。p210和p190 BCR-ABL载体均诱导了IL-3非依赖性生长，cEpo-R载体也得到了相同的结果。表达BCR-ABL的Ba/F3细胞的各个克隆对依托泊苷、血清剥夺或生长因子撤除诱导的凋亡表现出显著抗性。相比之下，表达组成型活性cEpoR的Ba/F3细胞在用依托泊苷类似处理或血清剥夺时，表现得像经历凋亡的亲本Ba/F3细胞。在所有BCR-ABL和cEpoR转染的克隆中，Bc12和Bax水平相似。然而，在凝胶迁移实验中，与在所有表达p210或p190 BCR-ABL的Ba/F3克隆中检测到的组成型STAT激活相反，来自表达cEpoR的生长因子非依赖性Ba/F3克隆的核提取物没有可检测到的STAT活性。我们的结果表明，虽然组成型激活的cEpoR和BCR-ABL癌基因都能在Ba/F3细胞中诱导生长因子非依赖性，但只有BCR-ABL能够保护细胞免受依托泊苷和血清剥夺诱导的凋亡，并诱导STAT因子的强烈组成型激活，这表明这些分子在BCR-ABL的抗凋亡活性中起作用。
