Role of lncRNA CYTOR/miR-193b-3p/HMGB1 axis in regulating the proliferation and apoptosis of T cell acute lymphoblastic leukemia MOLT-4 cell

Objective To investigate the effect of lncRNA CYTOR on the proliferation and apoptosis of T cell acute lymphoblastic leukemia (T-ALL) cells and its possible mechanism.

Methods Human normal bone marrow stromal cell lines HS-5 and T-ALL cell lines (CCRF-CEM, MOLT-4 and CEM-C1) were cultured in vitro, and then the expression of lncRNA CYTOR, miR-193b-3p and HMGB1 mRNA in the cells were detected by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), and the expression of HMGB1 protein in the cells were detected by western blot. MOLT-4 cells were transfected with si-CYTOR, miR-193b-3p mimics, si-HMGB1, or co-transfected with si-CYTOR and anti-miR-193b-3p, respectively. And then CCK-8 was used to detect cell proliferation. Flow cytometry was used to detect cell apoptosis, and western blot was used to detect the protein expression of Bax, cleaved-caspase3 and Bcl-2 in cells. The dual luciferase reporter gene experiment was used to verify the regulatory relationship between lncRNA CYTOR and miR-193b-3p, miR-193b-3p and HMGB1.

Results Compared with HS-5 cells, the expressions of lncRNA CYTOR and HMGB1 mRNA and its protein in T-ALL cell lines (CCRF-CEM, MOLT-4 and CEM-C1) were significantly increased, the expression of miR-193b-3p were significantly decreased (P < 0.05). After down-regulating lncRNA CYTOR, up-regulating miR-193b-3p, or down-regulating HMGB1, MOLT-4 cell proliferation was inhibited, the expression of Bcl-2 protein in cells significantly decreased, and the rate of apoptosis and the protein expression of Bax, cleaved-caspase3 in cells were significantly increased (P < 0.05). LncRNA CYTOR competitively adsorbed miR-193b-3p, and HMGB1 was the target gene of miR-193b-3p. Up-regulation of HMGB1 expression reversed the effects of lncRNA CYTOR on the proliferation and apoptosis of MOLT-4 in T-ALL cells. Knockdown of miR-193b-3p reversed the effects of lncRNA CYTOR on the proliferation and apoptosis of MOLT-4 cell.

Conclusion The expression of lncRNA CYTOR is up-regulated in T-ALL cell lines. It may promote T-ALL cells proliferation and hinder cell apoptosis by competitively adsorbing miR-193b-3p and then up-regulating the expression of HMGB1. It may become a molecular target for T-ALL treatment.