Jia Jin-Song, Salvatore Spicuglia
Peking University Institute of Hematology, Beijing, China.
Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2013 Apr;21(2):273-8. doi: 10.7534/j.issn.1009-2137.2013.02.003.
This study was purposed to detect the methylation status in promoter region of RUNX2 gene and its expression in cell lines and patients with HOX11(+) T-cell acute lymphoblastic leukemia (T-ALL) and to explore the relationship between the expression level of RUNX2 gene and methylation of CpG island in its promoter region. The methylation pattem in promoter region of RUNX2 gene was detected with bisulfite sequencing PCR, DNA methylation immunoprecipitation technique and promoter oligonucleotide microarray analysis and the expression levels of RUNX2 mRNA was detected with RT-PCR in 3 T-ALL cell lines (sil-ALL, DND41 and RPMI), as well as in 75 clinic bone marrow samples including 38 de novo T-ALL patients, 29 complete remission T-ALL patients and 8 normal samples. The results showed that there were hypermethylation of CpG island in promoter region of RUNX2 gene in patients with highly expressing HOX11(+) T-ALL. The methylation rate of the promoter CpG islands of RUNX2 gene in HOX11(+) T-ALL (78.9%) was significantly higher than that in HOX11(-) T-ALL (36.8%) (P < 0.01). The expression of RUNX2 in HOX11(+) cell lines was significantly lower than that in HOX11(-) cell lines, and the expression level of RUNX2 in the HOX11(+) T-ALL patients (0.581 ± 0.257) was significantly lower than that in HOX11(-) T-ALL patients (0.835 ± 0.317). The relationship between RUNX2 and HOX11 mRNA expression level showed a negative correlation (rs = -0.378, P < 0.01). The expression levels of RUNX2 gene negatively correlated with the methylation of CpG island in its promoter region (rs = -0.419, P < 0.01). It is concluded that HOX11 is a negative regulator of RUNX2 gene and the expression of RUNX2 is down regulated or even lost by promoter methylation in T-ALL, which demonstrate a better event-free survival and a marked trend for longer overall survival for HOX11-high T-ALLs. The expression and methylation level of RUNX2 gene may have some significance in evaluating the curative effect of T-ALL. The abnormal expression of RUNX2 may be a prognostic marker in T-ALL patients.
本研究旨在检测HOX11(+) T细胞急性淋巴细胞白血病（T-ALL）细胞系及患者中RUNX2基因启动子区域的甲基化状态及其表达情况，探讨RUNX2基因表达水平与其启动子区域CpG岛甲基化之间的关系。采用亚硫酸氢盐测序PCR、DNA甲基化免疫沉淀技术和启动子寡核苷酸微阵列分析检测RUNX2基因启动子区域的甲基化模式，采用RT-PCR检测3种T-ALL细胞系（sil-ALL、DND41和RPMI）以及75例临床骨髓样本（包括38例初发T-ALL患者、29例完全缓解T-ALL患者和8例正常样本）中RUNX2 mRNA的表达水平。结果显示，HOX11(+)高表达T-ALL患者RUNX2基因启动子区域CpG岛存在高甲基化。HOX11(+) T-ALL中RUNX2基因启动子CpG岛的甲基化率（78.9%）显著高于HOX11(-) T-ALL（36.8%）（P < 0.01）。HOX11(+)细胞系中RUNX2的表达显著低于HOX11(-)细胞系，HOX11(+) T-ALL患者中RUNX2的表达水平（0.581±0.257）显著低于HOX11(-) T-ALL患者（0.835±0.317）。RUNX2与HOX11 mRNA表达水平之间呈负相关（rs = -0.378，P < 0.01）。RUNX2基因的表达水平与其启动子区域CpG岛的甲基化呈负相关（rs = -0.419，P < 0.01）。结论：HOX11是RUNX2基因的负调节因子，T-ALL中RUNX2的表达因启动子甲基化而下调甚至缺失，这表明HOX11高表达的T-ALL具有更好的无事件生存率和明显更长的总生存趋势。RUNX2基因的表达和甲基化水平可能对评估T-ALL的疗效具有一定意义。RUNX2的异常表达可能是T-ALL患者的一个预后标志物。
