[Relation of miR-140 Expression Level with Therapeutic Effect of Decitabine and Its Mechanism]

To investigate the relationship of miR-140 expression level with the therapeutic effect of decitabine, and to explore whether the molecular mechanism is dependent on the regulation of TLR4 expression.

Forty-seven patients with acute myeloid leukaemia (AML) were enrolled in our study and divided into decitabine combination treatment group (22 cases) and traditional treatment group (25 cases). The clinical efficacy was compared between these two groups. Real-time PCR was used to determine the plasma level of miR-140 in AML patients. Decitabine, miR-140 mimic and miR140 inhibitor were used to treat AML HL-60 cells in vitro, the real-time PCR and Western blot were used to detect the expressions of miR-140, TLR4 and NF-κB at both mRNA and protein levels.

Compared with traditional treatment group, decitabine combination treatment group showed more significant clinical efficacy. Plasma miR-140 level in both 2 treatment groups both decreased, but the plasma miR-140 level was higher in decitabine combination treatment group as compared with traditional treatment group. Experiment in vitro showed that 0.3 μmol/L decitabine significantly inhibited the HL-60 cell proliferation accompanied by up-regulation of miR-140 expression and down-regulation of expression of TLR4 and NF-κB. These effects induced by decitabine were partly reversed by pretreating the cells with 200 nmol/L miR-140 inhibitor.

Decitabine-induced up-regulation of miR-140 expression may be related with its chemotherapeutic effects, and miR-140/TLR4/NF-κB pathway may partly mediate the pharmacologic action of decitabine.