Dual Targeting of Anti-Apoptotic Proteins Enhances Chemosensitivity of the Acute Myeloid Leukemia Cells

BACKGROUND: Acute myeloid leukemia (AML) is a type of blood cancer characterized by fast cellular proliferation. Myeloid cell leukemia-1 (Mcl-1) and survivin, as anti-apoptotic proteins, are involved in cancer growth and resistance to chemotherapy. The aim of this study was to examine the combination effect of Mcl-1 and survivin specific siRNAs on chemosensitivity of the human HL-60 AML cells. METHODS: SiRNAs transfection was performed by using Lipofectamine™2000 reagent. The mRNA expression was analyzed by real-time quantitative PCR. The apoptosis analysis was measured by ELISA cell death assay. RESULTS: siRNAs markedly suppressed mRNA expression levels of Mcl-1 and survivin in a time-dependent manner, resulting in reduction of leukemic cell proliferation and enhanced spontaneous cell death. Surprisingly, Mcl-1 siRNA and survivin siRNA synergistically enhanced the cell toxic effects of etoposide. Furthermore, down-regulation of Mcl-1 and survivin significantly enhanced the apoptotic effect of etoposide. CONCLUSIONS: Our investigation suggests that suppression of Mcl-1 and survivin by siRNA can effectually inhibit cell growth and overcome chemoresistance of AML cells. Therefore siRNAs may be an important adjuvant in chemotherapy for AML patients.