Acute myeloid leukemia (AML) with partial tandem duplication of histone-lysine N-methyltransferase 2A (KMT2A-PTD) is a subtype of AML and is associated with adverse survival, yet the molecular pathogenesis of KMT2A-PTD is not fully understood. DNA methyltransferase 3A (DNMT3A) is mutated in various myeloid neoplasms including AML, especially at the Arg882. Recently, it has been found that DNMT3A mutations frequently coexisted with KMT2A-PTD and are associated with inferior outcomes. We aimed to understand the biological role of DNMT3A mutation in KMT2A-PTD-positive cells. Herein, we found that overexpression of DNMT3A mutants (MT) in KMT2A-PTD-positive EOL-1 cells augmented cell proliferation and clonogenicity. Serial colony replating assays indicated that DNMT3A-MT increased the self-renewal ability of Kmt2a-PTD-expressing mouse bone marrow cells with immature morphology. At 10 months post bone marrow transplantation, mice with the combined Kmt2a-PTD and DNMT3A-MT showed hepatosplenomegaly and leukocytosis with a shorter latency compared to control and DNMT3A-wild-type. Gene expression microarray analyses of bone marrow samples from human AML with KMT2A-PTD/DNMT3A-MT showed a stem cell signature and myeloid hematopoietic lineage with dysregulation of HOXB gene expression. In addition, human bone marrow AML cells carrying KMT2A-PTD/DNMT3A-MT showed abnormal growth and augmented self-renewal activity in primary cell culture. The present study provides information underlying the pathogenic role of DNMT3A-MT with KMT2A-PTD in proliferating advantage with augmentation of self-renewal activity in human leukemia, which may help to better understand the disease and to design better therapy for AML patients with these mutations.

中文翻译：

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DNMT3A 突变体通过增强 KMT2A-PTD 阳性白血病细胞 AML 发病机制中的自我更新活性提供了增殖优势。

组蛋白-赖氨酸 N-甲基转移酶 2A (KMT2A-PTD) 部分串联重复的急性髓性白血病 (AML) 是 AML 的一种亚型，与不良生存相关，但 KMT2A-PTD 的分子发病机制尚不完全清楚。DNA 甲基转移酶 3A (DNMT3A) 在包括 AML 在内的各种骨髓肿瘤中发生突变，尤其是在 Arg882 处。最近，人们发现 DNMT3A 突变经常与 KMT2A-PTD 共存，并与较差的结果相关。我们旨在了解 DNMT3A 突变在 KMT2A-PTD 阳性细胞中的生物学作用。在这里，我们发现 KMT2A-PTD 阳性 EOL-1 细胞中 DNMT3A 突变体 (MT) 的过表达增强了细胞增殖和克隆形成。连续集落重铺试验表明，DNMT3A-MT 增加了表达 Kmt2a-PTD 的具有未成熟形态的小鼠骨髓细胞的自我更新能力。在骨髓移植后 10 个月，与对照和 DNMT3A-野生型相比，具有组合 Kmt2a-PTD 和 DNMT3A-MT 的小鼠表现出肝脾肿大和白细胞增多，潜伏期较短。用 KMT2A-PTD/DNMT3A-MT 对来自人类 AML 的骨髓样本进行的基因表达微阵列分析显示了干细胞特征和骨髓造血谱系与 HOXB 基因表达的失调。此外，携带 KMT2A-PTD/DNMT3A-MT 的人骨髓 AML 细胞在原代细胞培养中表现出异常生长和增强的自我更新活性。