Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan.
Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan. College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Clin Cancer Res. 2015 Aug 1;21(15):3541-51. doi: 10.1158/1078-0432.CCR-14-2203. Epub 2015 Apr 3.
Transcription factor RUNX1 is essential for normal hematopoiesis. High mutation frequencies of RUNX1 gene in chronic myelomonocytic leukemia (CMML) and myelodysplastic syndromes (MDS) have been described, whereas the biologic significances of the mutations were not investigated. Here, we aimed to correlate the biologic activities of the RUNX1 mutants with the clinical outcomes of patients.
We examined the mutational status of RUNX1 in 143 MDS and 84 CMML patients. Then, we studied the DNA and CBFβ binding abilities of all the RUNX1 mutants identified by using electrophoretic mobility shift assay and co-immunoprecipitation assay, and also determined their activities on target C-FMS gene induction by Western blotting and luciferase reporter assay. Using luciferase reporter assay, the relative biologic activities of each RUNX1 mutant could be quantified and correlated with the patient outcomes by statistical analyses.
We observed that most RUNX1 mutants had reduced abilities in DNA binding, CBFβ heterodimerization, and C-FMS gene induction. The relative biologic activities of RUNX1 mutants were grouped into high- and low-activity mutations. Correlation of the activities of RUNX1 mutants with the clinical outcomes revealed that patients harboring lower activities of RUNX1 mutants had a higher risk and shorter time to secondary acute myeloid leukemia transformation in MDS and CMML. In multivariate analysis, low RUNX1 activity remained an independent predictor for secondary acute myeloid leukemia-free survival in MDS patients.
The biologic activity rather than the mutational status of RUNX1 might be an indicator in predicting outcome of patients with MDS and CMML.
转录因子 RUNX1 对正常造血至关重要。慢性粒单核细胞白血病（CMML）和骨髓增生异常综合征（MDS）中 RUNX1 基因的突变频率较高，但突变的生物学意义尚未得到研究。在这里，我们旨在将 RUNX1 突变体的生物学活性与患者的临床结果相关联。
我们检查了 143 例 MDS 和 84 例 CMML 患者的 RUNX1 突变状态。然后，我们使用电泳迁移率变动分析和共免疫沉淀分析研究了所有鉴定出的 RUNX1 突变体的 DNA 和 CBFβ 结合能力，还通过 Western blot 和荧光素酶报告基因分析确定了它们对靶基因 C-FMS 诱导的活性。通过荧光素酶报告基因分析，可以定量每个 RUNX1 突变体的相对生物学活性，并通过统计分析将其与患者结果相关联。
我们观察到大多数 RUNX1 突变体的 DNA 结合、CBFβ 异二聚体形成和 C-FMS 基因诱导能力降低。RUNX1 突变体的相对生物学活性分为高活性和低活性突变。RUNX1 突变体活性与临床结果的相关性表明，携带低活性 RUNX1 突变体的患者在 MDS 和 CMML 中发生继发性急性髓系白血病转化的风险更高，时间更短。在多变量分析中，低 RUNX1 活性仍然是 MDS 患者继发性急性髓系白血病无复发生存的独立预测因子。
RUNX1 的生物学活性而不是突变状态可能是预测 MDS 和 CMML 患者预后的指标。
