N⁶-methyladenosine (m⁶A) is an abundant nucleotide modification in mRNA that is required for the differentiation of mouse embryonic stem cells. However, it remains unknown whether the m⁶A modification controls the differentiation of normal and/or malignant myeloid hematopoietic cells. Here we show that shRNA-mediated depletion of the m⁶A-forming enzyme METTL3 in human hematopoietic stem/progenitor cells (HSPCs) promotes cell differentiation, coupled with reduced cell proliferation. Conversely, overexpression of wild-type METTL3, but not of a catalytically inactive form of METTL3, inhibits cell differentiation and increases cell growth. METTL3 mRNA and protein are expressed more abundantly in acute myeloid leukemia (AML) cells than in healthy HSPCs or other types of tumor cells. Furthermore, METTL3 depletion in human myeloid leukemia cell lines induces cell differentiation and apoptosis and delays leukemia progression in recipient mice in vivo. Single-nucleotide-resolution mapping of m⁶A coupled with ribosome profiling reveals that m⁶A promotes the translation of c-MYC, BCL2 and PTEN mRNAs in the human acute myeloid leukemia MOLM-13 cell line. Moreover, loss of METTL3 leads to increased levels of phosphorylated AKT, which contributes to the differentiation-promoting effects of METTL3 depletion. Overall, these results provide a rationale for the therapeutic targeting of METTL3 in myeloid leukemia.

中文翻译：

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N6-甲基腺苷 (m6A) 形成酶 METTL3 控制正常造血细胞和白血病细胞的骨髓分化。

N ⁶ -甲基腺苷 (m ⁶ A) 是 mRNA 中丰富的核苷酸修饰，是小鼠胚胎干细胞分化所必需的。然而，m ⁶ A 修饰是否控制正常和/或恶性骨髓造血细胞的分化仍然未知。在这里，我们表明 shRNA 介导的 m ⁶耗竭人类造血干/祖细胞 (HSPC) 中的 A 形成酶 METTL3 促进细胞分化，同时减少细胞增殖。相反，野生型 METTL3 而非催化失活形式的 METTL3 的过表达会抑制细胞分化并促进细胞生长。METTL3 mRNA 和蛋白质在急性髓系白血病 (AML) 细胞中的表达比在健康 HSPC 或其他类型的肿瘤细胞中更丰富。此外，人髓系白血病细胞系中的 METTL3 耗竭诱导细胞分化和凋亡，并在体内延迟受体小鼠的白血病进展。m ⁶ A 的单核苷酸分辨率图谱结合核糖体分析表明 m ⁶A 在人急性髓性白血病 MOLM-13 细胞系中促进 c-MYC、BCL2 和 PTEN mRNA 的翻译。此外，METTL3 的缺失导致磷酸化 AKT 水平增加，这有助于 METTL3 耗竭的分化促进作用。总体而言，这些结果为 METTL3 在髓系白血病中的治疗靶向提供了理论依据。