Department of Zoology, Faculty of Natural Sciences, University of Tabriz.
Daru. 2011;19(6):455-61.
Leukemia is a malignant disorder of the blood progenitor/stem cells which is characterized by abnormal proliferation of white blood cells. Although anti-cancer drugs induce apoptosis in cancerous cells, drug resistance is the significant problem mainly due to over-expression of inhibitors of apoptosis proteins (IAPs) such as survivin. In this content, it has been reported that an anti-inflammatory drug, Carbenoxolone (CBX), could induce apoptosis and growth inhibition in several types of cancerous cells. In the present study, effects of CBX on apoptosis and level of the expression of survivin gene and its ΔEx3 splicing variant have were evaluated in K562 cells.
K562 cells were cultured and treated with different concentrations of CBX (50-300 µM) at different time intervals (12-48 hrs). Trypan blue exclusion test was used to evaluate cell viability. Fluorescent microscopy (Acridine Orange/Ethidium Bromide double staining) and DNA fragmentation assay were used to study apoptosis. The expression level of survivin and its ΔEx3 splice variant were studied by RT-PCR.
It was found that both growth inhibition and apoptosis occurred in K562 cells. In addition, down-regulation of survivin and survin-ΔEx3 were observed, after 2-4 hrs treatment with 150 µM of CBX. However, the expression level of survivin and its ΔEx3 splice variant increased in subsequent time (6-12 hrs) nearly to the level of control cells. From the results of this study, it may be concluded that CBX can be considered as a candidate for further studies in CML treatment, especially in the case of drug-resistant leukemia cells.
白血病是一种血液祖/干细胞的恶性疾病，其特征是白细胞异常增殖。尽管抗癌药物可诱导癌细胞凋亡，但耐药性是一个主要问题，主要是由于凋亡抑制蛋白（IAPs）如生存素的过度表达。在本研究中，已报道抗炎药物卡波氯铵（CBX）可诱导几种类型癌细胞的凋亡和生长抑制。在本研究中，评估了 CBX 对 K562 细胞凋亡和生存素基因及其 ΔEx3 剪接变异体表达水平的影响。
将 K562 细胞培养并以不同浓度的 CBX（50-300μM）处理不同时间间隔（12-48 小时）。使用台盼蓝排除试验评估细胞活力。荧光显微镜（吖啶橙/溴化乙锭双重染色）和 DNA 片段化分析用于研究凋亡。通过 RT-PCR 研究生存素及其 ΔEx3 剪接变异体的表达水平。
结果发现，K562 细胞既发生生长抑制又发生凋亡。此外，在用 150μM CBX 处理 2-4 小时后，观察到生存素和 survin-ΔEx3 的下调。然而，在随后的时间（6-12 小时），生存素及其 ΔEx3 剪接变异体的表达水平增加，几乎达到对照细胞的水平。从本研究的结果可以得出结论，CBX 可以被认为是 CML 治疗的进一步研究的候选药物，特别是在耐药性白血病细胞的情况下。
