Liu H B, Urbanavicius D, Tan P, Spencer A, Dear A E
Australian Centre for Blood Diseases, Monash University, Prahran 3181, Melbourne, Victoria, Australia.
Int J Oncol. 2014 Oct;45(4):1742-8. doi: 10.3892/ijo.2014.2555. Epub 2014 Jul 22.
Combination epigenetic treatment (EGT) utilizing DNA methyl transferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi) may be more efficacious than single agent treatment in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). The molecular mechanisms behind the potential clinical efficacy of combination EGT treatment are incompletely understood and the frequently lengthy EGT regimes required to determine clinical response have generated a significant demand for early molecular markers of treatment response. Our study aimed to identify the effect of combination azacitidine (AZA) and panobinostat (LBH589) on expression levels of a panel of genes implicated in the pathogenesis of high-risk MDS or AML in HL-60 cells. We also characterized gene expression profiles in peripheral blood mononuclear (PBMCs) from patients in a recently reported phase Ib/II clinical trial using the combination of AZA and LBH589 and correlated these findings with clinical response to treatment. In vitro analysis demonstrated increased expression of caspase-3, Nor-1, NUR77, p15INK4B and p21WAF1/CIP1 and decreased expression of Bcl‑xL in HL-60 cells treated with combination EGT. Analysis of patient samples prior to treatment demonstrated a significant reduction in NUR77 and p21WAF1/CIP1 expression compared to healthy controls. NUR77 and p21WAF1/CIP1 levels were similar between treatment non‑responders and responders at screening. Early post first cycle treatment (day 25) analysis demonstrated a significant increase in expression of both NUR77, and p21WAF1/CIP1. A significant increase in NUR77, and p21WAF1/CIP1 together with a trend to increase in p15INK4B first cycle expression was observed in treatment responders compared to non-responders. In summary, combination AZA and LBH589 epigenetic treatment is associated with in vitro and in vivo modulation of genes implicated in the pathogenesis of MDS/AML. Early expression of NUR77 and p21WAF1/CIP1 correlated with clinical response to combination EGT suggesting investigation for potential use as molecular markers of early treatment response may be warranted.
在骨髓增生异常综合征（MDS）和急性髓系白血病（AML）中，利用DNA甲基转移酶抑制剂（DNMTi）和组蛋白去乙酰化酶抑制剂（HDACi）的联合表观遗传治疗（EGT）可能比单药治疗更有效。联合EGT治疗潜在临床疗效背后的分子机制尚未完全明确，而且确定临床反应所需的EGT疗程通常较长，这使得人们对治疗反应的早期分子标志物产生了巨大需求。我们的研究旨在确定阿扎胞苷（AZA）和帕比司他（LBH589）联合使用对一组与高危MDS或AML发病机制相关的基因在HL-60细胞中的表达水平的影响。我们还对最近报道的一项使用AZA和LBH589联合治疗的Ib/II期临床试验中患者外周血单个核细胞（PBMC）的基因表达谱进行了特征分析，并将这些结果与治疗的临床反应相关联。体外分析表明，联合EGT处理的HL-60细胞中，半胱天冬酶-3、Nor-1、NUR77、p15INK4B和p21WAF1/CIP1的表达增加，而Bcl-xL的表达降低。治疗前对患者样本的分析表明，与健康对照相比，NUR77和p21WAF1/CIP1的表达显著降低。在筛查时，治疗无反应者和有反应者之间的NUR77和p21WAF1/CIP1水平相似。首次治疗周期后早期（第25天）分析表明，NUR77和p21WAF1/CIP1的表达均显著增加。与无反应者相比，有反应者中观察到NUR77和p21WAF1/CIP1显著增加，同时p15INK4B在第一个周期的表达有增加趋势。总之，AZA和LBH589联合表观遗传治疗与MDS/AML发病机制相关基因的体外和体内调节有关。NUR77和p21WAF1/CIP1的早期表达与联合EGT的临床反应相关，这表明对其作为早期治疗反应分子标志物的潜在用途进行研究可能是有必要的。
