HOTAIRM1 knockdown enhances cytarabine-induced cytotoxicity by suppression of glycolysis through the Wnt/β-catenin/PFKP pathway in acute myeloid leukemia cells

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 AraC 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/beta-catenin signaling pathway, HL60 and THP-1 cells were transfected with beta-catenin overexpressing plasmid (pcDNA-beta-catenin). Protein levels of PFKP, beta-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/beta-catenin pathway. Furthermore, activating Wnt/beta-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/beta-catenin/PFKP signaling pathway. These findings suggested that HOTAIRM1 might be a therapeutic target for overcoming the Ara-C resistance in AML.