Abstract：
BACKGROUND: Secondary genetic alterations, which contribute to the dysregulation of cell cycle progression and lymphoid specialization, are frequently observed in B-cell precursor acute lymphoblastic leukemia (B-ALL). As IKZF1 and BTG1 deletions are associated with a worse outcome in B-ALL, this study aimed to address whether they synergistically promote glucocorticoid resistance.
METHODS: Small interfering RNA was used to downregulate either IKZF1, or BTG1, or both genes in the 207 B-ALL cell line. Cell viability was investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and trypan blue exclusion assays. The expression levels of IKZF1, BTG1 and glucocorticoid-responsive genes (DUSP1, SGK1, FBXW7 and NR3C1) were evaluated by real time quantitative real time polymerase chain reaction (PCR).
RESULTS: Isolated silencing of BTG1, IKZF1, or both genes in combination under dexamethasone treatment increased cell viability by 24%, 40% and 84%, respectively. Although BTG1 silencing did not alter the expression of glucocorticoid-responsive genes, IKZF1 knockdown decreased the transcript levels of DUSP1 (2.6-fold), SGK1 (1.8-fold), FBXW7 (2.2-fold) and NR3C1 (1.7-fold). The expression of glucocorticoid-responsive genes reached even lower levels (reducing 2.4-4 fold) when IKZF1 and BTG1 silencing occurred in combination.
CONCLUSIONS: IKZF1 silencing impairs the transcription of glucocorticoid-responsive genes; this effect is enhanced by concomitant loss of BTG1. These results demonstrate the molecular mechanism by which the combination of both genetic deletions might contribute to higher relapse rates in B-ALL.
METHODS: Small interfering RNA was used to downregulate either IKZF1, or BTG1, or both genes in the 207 B-ALL cell line. Cell viability was investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and trypan blue exclusion assays. The expression levels of IKZF1, BTG1 and glucocorticoid-responsive genes (DUSP1, SGK1, FBXW7 and NR3C1) were evaluated by real time quantitative real time polymerase chain reaction (PCR).
RESULTS: Isolated silencing of BTG1, IKZF1, or both genes in combination under dexamethasone treatment increased cell viability by 24%, 40% and 84%, respectively. Although BTG1 silencing did not alter the expression of glucocorticoid-responsive genes, IKZF1 knockdown decreased the transcript levels of DUSP1 (2.6-fold), SGK1 (1.8-fold), FBXW7 (2.2-fold) and NR3C1 (1.7-fold). The expression of glucocorticoid-responsive genes reached even lower levels (reducing 2.4-4 fold) when IKZF1 and BTG1 silencing occurred in combination.
CONCLUSIONS: IKZF1 silencing impairs the transcription of glucocorticoid-responsive genes; this effect is enhanced by concomitant loss of BTG1. These results demonstrate the molecular mechanism by which the combination of both genetic deletions might contribute to higher relapse rates in B-ALL.
摘要：
背景：次要遗传改变，这有助于细胞周期进程和淋巴特化的失调，在B细胞前体急性淋巴细胞白血病（B-ALL）中经常观察到。由于IKZF1和BTG1缺失与B-ALL的不良结果相关，本研究旨在探讨它们是否协同促进糖皮质激素耐药.
方法：使用小干扰RNA下调207B-ALL细胞系中的IKZF1或BTG1或这两种基因。通过3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四唑溴化物（MTT）和台盼蓝排除法研究细胞活力。通过实时定量实时聚合酶链反应（PCR）评估IKZF1，BTG1和糖皮质激素反应基因（DUSP1，SGK1，FBXW7和NR3C1）的表达水平。
结果：在地塞米松处理下，BTG1、IKZF1或两种基因的分离沉默使细胞活力增加了24%，40%和84%，分别。虽然BTG1沉默并没有改变糖皮质激素反应基因的表达，IKZF1敲除降低了DUSP1的转录水平（2.6倍），SGK1（1.8倍），FBXW7(2.2倍)和NR3C1(1.7倍)。当IKZF1和BTG1联合沉默时，糖皮质激素反应基因的表达甚至达到更低的水平（减少2.4-4倍）。
结论：IKZF1沉默会损害糖皮质激素反应基因的转录；伴随的BTG1丢失会增强这种作用。这些结果证明了两种遗传缺失的组合可能导致B-ALL中更高的复发率的分子机制。
方法：使用小干扰RNA下调207B-ALL细胞系中的IKZF1或BTG1或这两种基因。通过3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四唑溴化物（MTT）和台盼蓝排除法研究细胞活力。通过实时定量实时聚合酶链反应（PCR）评估IKZF1，BTG1和糖皮质激素反应基因（DUSP1，SGK1，FBXW7和NR3C1）的表达水平。
结果：在地塞米松处理下，BTG1、IKZF1或两种基因的分离沉默使细胞活力增加了24%，40%和84%，分别。虽然BTG1沉默并没有改变糖皮质激素反应基因的表达，IKZF1敲除降低了DUSP1的转录水平（2.6倍），SGK1（1.8倍），FBXW7(2.2倍)和NR3C1(1.7倍)。当IKZF1和BTG1联合沉默时，糖皮质激素反应基因的表达甚至达到更低的水平（减少2.4-4倍）。
结论：IKZF1沉默会损害糖皮质激素反应基因的转录；伴随的BTG1丢失会增强这种作用。这些结果证明了两种遗传缺失的组合可能导致B-ALL中更高的复发率的分子机制。
