Cystathionine-beta-synthase cDNA transfection alters the sensitivity and metabolism of 1-beta-D-arabinofuranosylcytosine in CCRF-CEM leukemia cells in vitro and in vivo: a model of leukemia in Down syndrome.
Cystathionine-beta-synthase cDNA transfection alters the sensitivity and metabolism of 1-beta-D-arabinofuranosylcytosine in CCRF-CEM leukemia cells in vitro and in vivo: a model of leukemia in Down syndrome.
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发表时间：
2000-11
期刊：
影响因子：
11.2
通讯作者：
J. Taub;Xi Huang;Y. Ge;J. Dutcher;M. Stout;R. Mohammad;Y. Ravindranath;L. Matherly
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作者：
J. Taub;Xi Huang;Y. Ge;J. Dutcher;M. Stout;R. Mohammad;Y. Ravindranath;L. Matherly
与非唐氏综合征（DS）儿童相比，患有急性髓性白血病的唐氏综合征（DS）儿童的无事件存活率显著更高，这与DS成髓细胞对1-β-D-阿拉伯呋喃糖基胞嘧啶（ara-C）的敏感性增加以及ara-C向ara-C三磷酸盐的代谢增强有关（J.W. Taub等人，Blood，87：3395-3403，1996）。胱硫醚-β-合酶（CBS）基因（位于染色体21q22.3）可能对还原叶酸和S-腺苷甲硫氨酸途径具有下游效应;阿糖胞苷代谢和叶酸池通过甲氨蝶呤和阿糖胞苷序贯治疗的已知协同效应联系在一起。我们已经表明，与非DS成髓细胞相比，DS中的相对CBS转录物显著更高，并且CBS转录物水平与体外阿糖胞苷敏感性相关（J. W. Taub等人，Blood，94：1393-1400，1999）。通过转染CBS基因缺失的CCRF-CEM细胞，建立了CBS基因与阿糖胞苷代谢/敏感性关系的白血病细胞系模型。与野生型细胞相比，CBS转染的细胞在体外对阿糖胞苷的敏感性中值高15倍，并且在与[3 H]阿糖胞苷体外孵育后产生的[3 H]阿糖胞苷三磷酸水平高8.5倍。严重的联合免疫缺陷小鼠植入CBS转染的CEM细胞表现出更大的治疗反应，反映在阿糖胞苷给药后的生存期显着延长与野生型细胞植入小鼠和相同的剂量方案治疗。转染的细胞还表现出对吉西他滨的体外和体内敏感性增加。脱氧胞苷激酶（dCK）的活性是约22倍，高转染CEM细胞与野生型细胞相比。然而，北方印迹上的dCK转录物水平和蛋白质印迹上的蛋白质水平在CBS转染的细胞和野生型细胞之间几乎相同。总的来说，这些结果表明在CBS过表达细胞中dCK的转录后调节有助于增加ara-C磷酸化和药物活性。进一步阐明与CBS基因相关的DS细胞对阿糖胞苷敏感性增加的机制可能会导致这些新方法在非DS患者急性髓系白血病治疗中的应用。
The significantly higher event-free survival rates of Down syndrome (DS) children with acute myeloid leukemia compared with non-DS children is linked to increased sensitivity of DS myeloblasts to 1-beta-D-arabinofuranosylcytosine (ara-C) and the enhanced metabolism of ara-C to ara-C triphosphate (J. W. Taub et al., Blood, 87: 3395-3403, 1996). The cystathionine-beta-synthase (CBS) gene (localized to chromosome 21q22.3) may have downstream effects on reduced folate and S-adenosylmethionine pathways; ara-C metabolism and folate pools are linked by the known synergistic effect of sequential methotrexate and ara-C therapy. We have shown that relative CBS transcripts were significantly higher in DS compared with non-DS myeloblasts, and CBS transcript levels correlated with in vitro ara-C sensitivity (J. W. Taub et al., Blood, 94: 1393-1400, 1999). A leukemia cell line model to study the relationship of the CBS gene and ara-C metabolism/sensitivity was developed by transfecting CBS-null CCRF-CEM cells with the CBS cDNA. CBS-transfected cells were a median 15-fold more sensitive in vitro to ara-C compared with wild-type cells and generated 8.5-fold higher [3H]ara-C triphosphate levels after in vitro incubation with [3H]ara-C. Severe combined immunodeficient mice implanted with CBS-transfected CEM cells demonstrated greater responsiveness to therapy, reflected in significantly prolonged survivals after ara-C administration compared with mice implanted with wild-type cells and treated with the same dosage schedule. The transfected cells also demonstrated increased in vitro and in vivo sensitivity to gemcitabine. Deoxycytidine kinase (dCK) activity was approximately 22-fold higher in transfected CEM cells compared with wild-type cells. However, levels of dCK transcripts on Northern blots and protein levels on Western blots were nearly identical between CBS-transfected and wild-type cells. Collectively, these results suggest a posttranscriptional regulation of dCK in CBS-overexpressing cells that contributes to increased ara-C phosphorylation and drug activity. Further elucidating the mechanisms of increased sensitivity of DS cells to ara-C related to the CBS gene may lead to the application of these novel approaches to acute myeloid leukemia therapy for non-DS patients.