All-trans retinoic acid enhanced the antileukemic efficacy of ABT-199 in acute myeloid leukemia by downregulating the expression of S100A8.

Acute myeloid leukemia (AML) is prone to relapse. Targeted therapy with a specific inhibitor of the anti-apoptotic protein Bcl-2 ABT-199 is an effective method for relapsed and refractory patients, but drug resistance is likely, which is primarily related to high Mcl-1 and S100A8 expression. All-trans retinoic acid (ATRA) can inhibit Bcl-2 and Mcl-1 expression. The study purpose was to determine whether ATRA can enhance the antileukemia effect of ABT-199 on AML cells. Our data showed that ATRA combined with ABT-199 exerts a synergistic antileukemic effect by inducing apoptosis and cell cycle arrest in AML. In vivo, combination therapy prolonged the survival of AML xenograft mice. The possible mechanism involves promoting apoptosis through downregulation of S100A8 expression by inhibiting the PI3K/AKT signaling pathway. This study provides a potential treatment strategy and theoretical support for overcoming the clinical ABT-199 resistance problem in AML patients.