Amarante-Mendes G P, McGahon A J, Nishioka W K, Afar D E, Witte O N, Green D R
Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA.
Oncogene. 1998 Mar;16(11):1383-90. doi: 10.1038/sj.onc.1201664.
Bcr - Abl is the molecule responsible for both the transformation phenotype and the resistance to chemotherapeutic drugs found in chronic myelogenous leukemia (CML) cells. Wild-type HL-60, a transformed pro-myelocytic cell line, is very susceptible to apoptosis-inducing agents. We show here that expression of Bcr - Abl in HL-60 cells rendered them extremely resistant to apoptosis induced by a wide variety of agents. The anti-apoptotic effect of Bcr - Abl was found to be independent of the phase of the cell cycle. Treatment with antisense oligonucleotides directed to bcr decreased the expression of the ectopic bcr - abl and restored susceptibility to apoptosis. Double mutations affecting the autophosphorylation site and the phosphotyrosine-binding motif (FLVRES) have been previously shown to impair the transforming activity of Bcr - Abl in fibroblasts and hematopoietic cells, however HL-60 cells expressing this double mutant molecule exhibited the same level of resistance to apoptosis as those expressing the wild-type Bcr - Abl. Interestingly, wild type and mutant Bcr - Abl induced in HL-60 cells a dramatic down regulation of Bcl-2 and increased the levels of Bcl-xL. The level of Bax did not change in response to the presence of Bcr - Abl. Antisense oligonucleotides targeted to bcl-x downregulated the expression of Bcl-x, and increased the susceptibility of HL-60. Bcr - Abl cells to staurosporine. Importantly, HL-60 cells overexpressing Bcl-xL showed higher expression of Bcl-xL but lower resistance to apoptosis when compared to HL-60. Bcr - Abl cells. The results described here show that Bcr - Abl is a powerful mammalian anti-apoptotic molecule and can act independently of Bcl-2. Bcl-xL, however, seems to participate in part in Bcr - Abl-mediated resistance to apoptosis in HL-60 cells.
Bcr - Abl是慢性粒细胞白血病（CML）细胞中导致转化表型和对化疗药物耐药的分子。野生型HL - 60是一种转化的早幼粒细胞系，对凋亡诱导剂非常敏感。我们在此表明，HL - 60细胞中Bcr - Abl的表达使其对多种诱导剂诱导的凋亡具有极强的抗性。发现Bcr - Abl的抗凋亡作用与细胞周期阶段无关。用针对bcr的反义寡核苷酸处理可降低异位bcr - abl的表达，并恢复对凋亡的敏感性。先前已表明，影响自身磷酸化位点和磷酸酪氨酸结合基序（FLVRES）的双突变会损害成纤维细胞和造血细胞中Bcr - Abl的转化活性，然而，表达这种双突变分子的HL - 60细胞对凋亡的抗性水平与表达野生型Bcr - Abl的细胞相同。有趣的是，野生型和突变型Bcr - Abl在HL - 60细胞中诱导Bcl - 2显著下调，并增加了Bcl - xL的水平。Bax的水平在Bcr - Abl存在时没有变化。靶向bcl - x的反义寡核苷酸下调了Bcl - x的表达，并增加了HL - 60。Bcr - Abl细胞对星形孢菌素的敏感性。重要的是，与HL - 60相比，过表达Bcl - xL的HL - 60细胞显示出更高的Bcl - xL表达，但对凋亡的抗性更低。Bcr - Abl细胞。此处描述的结果表明，Bcr - Abl是一种强大的哺乳动物抗凋亡分子，并且可以独立于Bcl - 2发挥作用。然而，Bcl - xL似乎部分参与了HL - 60细胞中Bcr - Abl介导的抗凋亡作用。
