HOX antisense intergenic RNA myeloid 1 (HOTAIRM1) is a long non-coding RNA (lncRNA) that is highly specific for maturing myeloid cells. Dysregulation of HOTAIRM1 has been found to be implicated in the development of acute myeloid leukemia (AML). However, the role of HOTAIRM1 in the drug resistance in AML remains unknown. The present study aimed to investigate the effect of HOTAIRM1 on the cytarabine (Ara-C) resistance in leukemia cell lines and to explore the underlying mechanism. The leukemia cell lines, HL60 and THP-1, were transfected with HOTAIRM1 specific siRNA (si-HOTAIRM1) or control siRNA (si-ctrl), and then treated with Ara-C for 48 h. The mRNA levels of HOTAIRM1 and platelet-type phosphofructokinase (PFKP) were measured using RT-PCR. Cell viability was evaluated by MTT assay. Apoptosis was determined using flow cytometry and caspase-3/7 activity assay. Glycolysis was evaluated by determining the glucose consumption and lactate production. To activate the Wnt/β-catenin signaling pathway, HL60 and THP-1 cells were transfected with β-catenin overexpressing plasmid (pcDNA-β-catenin). Protein levels of PFKP, β-catenin, and c-Myc were examined using western blot analysis. The results showed that knockdown of HOTAIRM1 enhanced Ara-C-induced reduction of cell viability and increase of cell apoptosis. HOTAIRM1 knockdown suppressed the glucose consumption and lactate production, as well as the expression of PFKP in AML cells. Besides, HOTAIRM1 knockdown resulted in a significant inhibitory effect on the Wnt/β-catenin pathway. Furthermore, activating Wnt/β-catenin pathway mitigated the effects of HOTAIRM1 knockdown on glycolysis and Ara-C cytotoxicity in AML cells. In conclusion, knockdown of HOTAIRM1 enhanced Ara-C cytotoxicity through regulating the Wnt/β-catenin/PFKP signaling pathway. These findings suggested that HOTAIRM1 might be a therapeutic target for overcoming the Ara-C resistance in AML.

中文翻译：

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HOTAIRM1基因敲低通过抑制Wnt /β-catenin/ PFKP途径在急性髓样白血病细胞中的糖酵解作用来增强阿糖胞苷诱导的细胞毒性。

HOX反义基因间RNA髓样1（HOTAIRM1）是长的非编码RNA（lncRNA），对成熟的髓样细胞具有高度特异性。已发现HOTAIRM1的失调与急性髓细胞性白血病（AML）的发生有关。但是，HOTAIRM1在AML耐药中的作用仍然未知。本研究旨在研究HOTAIRM1对白血病细胞系中阿糖胞苷（Ara-C）抗性的影响，并探讨其潜在机制。用HOTAIRM1特异性siRNA（si-HOTAIRM1）或对照siRNA（si-ctrl）转染白血病细胞系HL60和THP-1，然后用Ara-C处理48小时。使用RT-PCR测量HOTAIRM1和血小板型磷酸果糖激酶（PFKP）的mRNA水平。细胞存活力通过MTT测定法评估。使用流式细胞仪和caspase-3 / 7活性测定法测定细胞凋亡。通过确定葡萄糖消耗和乳酸产生来评估糖酵解。为了激活Wnt /β-catenin信号通路，用β-catenin过表达质粒（pcDNA-β-catenin）转染HL60和THP-1细胞。使用蛋白质印迹分析检查了PFKP，β-catenin和c-Myc的蛋白质水平。结果表明，敲低HOTAIRM1增强了Ara-C诱导的细胞活力降低和细胞凋亡的增加。HOTAIRM1组合件抑制了AML细胞中的葡萄糖消耗和乳酸生成以及PFKP的表达。此外，HOTAIRM1基因敲低对Wnt /β-catenin途径具有明显的抑制作用。此外，激活Wnt /β-catenin途径可减轻HOTAIRM1敲低对AML细胞糖酵解和Ara-C细胞毒性的影响。总之，通过调节Wnt /β-catenin/ PFKP信号通路，HOTAIRM1的敲低增强了Ara-C的细胞毒性。这些发现表明，HOTAIRM1可能是克服AML中Ara-C耐药性的治疗靶标。