de Albuquerque Amanda, Lopes Bruno A, Fernandes Renan Amphilophio, Gimba Etel Rodrigues Pereira, Emerenciano Mariana
Division of Clinical Research and Technological Development, Instituto Nacional de Câncer (INCA), Rio de Janeiro, RJ, Brazil.
Division of Clinical Research and Technological Development, Instituto Nacional de Câncer (INCA), Rio de Janeiro, RJ, Brazil; Genetics of Acute Leukemia Laboratory, Molecular Carcinogenesis Program, Instituto Nacional de Câncer (INCA), Rio de Janeiro, RJ, Brazil.
Hematol Transfus Cell Ther. 2024 Dec;46 Suppl 6(Suppl 6):S163-S170. doi: 10.1016/j.htct.2024.05.004. Epub 2024 Jul 26.
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.
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).
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.
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.
继发性基因改变在B细胞前体急性淋巴细胞白血病（B-ALL）中经常被观察到，它会导致细胞周期进程失调和淋巴细胞特化异常。由于IKZF1和BTG1缺失与B-ALL的不良预后相关，本研究旨在探讨它们是否协同促进糖皮质激素抵抗。
使用小干扰RNA下调207 B-ALL细胞系中的IKZF1、BTG1或这两个基因。通过3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四氮唑溴盐（MTT）和台盼蓝排斥试验研究细胞活力。通过实时定量聚合酶链反应（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。
在地塞米松处理下，单独沉默BTG1、IKZF1或同时沉默这两个基因分别使细胞活力提高了24%、40%和84%。虽然沉默BTG1没有改变糖皮质激素反应基因的表达，但敲低IKZF1会降低DUSP1（2.6倍）, SGK1（1.8倍）, FBXW7（2.2倍）和NR3C1（1.7倍）的转录水平。当IKZF1和BTG1同时沉默时，糖皮质激素反应基因的表达水平更低（降低2.4-4倍）。
沉默IKZF1会损害糖皮质激素反应基因的转录；BTG1的同时缺失会增强这种作用。这些结果证明了这两种基因缺失的组合可能导致B-ALL更高复发率的分子机制。
