Down-regulation of bcl-2 and mcl-1 by mirna-15 and 16 synergistically enhances the apoptotic effects of abt-199 and fludarabin in cll cells

Nooshin Ashofteh,1,* Razie amini,2 Hadi karami,3

1. 4 Department of Molecular Medicine and Biotechnology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Ir
2. 4 Department of Molecular Medicine and Biotechnology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Ir
3. 4 Department of Molecular Medicine and Biotechnology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Ir

Abstract

Introduction

Mirna-15 and 16 can act as a tumor suppressor gene by interfering with bcl-2 and mcl-1. studies have demonstrated that overexpression of bcl-2 and mcl-1 is linked to the tumorogenesity and chemoresistance of cll (chronic lymphocytic leukemia) cells. the purpose of this study was to investigate if downregulation of bcl-2 and mcl-1 by mirna-15 and 16 could sensitize cll cells to anti-leukemia agents, abt-199 and fludarabine.

Methods

The cll-cii leukemia cells were transfected with mirna using lipofectamine™2000 transfection reagent. relative mcl-1 and bcl-2 mrna levels were monitored by quantitative real-time pcr. trypan blue exclusion assay was done to monitor cancer cell proliferation after mirna transfection. the cytotoxic effects of fludarabin, abt-199 and mirna-15,16, alone and in combination, on cells were explored using mtt assay. apoptosis was evaluated using elisa cell death assay.

Results

Mirna-15 and 16 markedly decreased mcl-1 and bcl-2 mrna levels in a time-dependent manner, leading to distinct cell proliferation inhibition and spontaneous apoptosis. surprisingly, mirna-15,16 synergistically enhanced the cell toxic effects of fludarabin and abt-199. moreover, combination of mir-15 and 16 further enhanced the chemosensitivity of the anti-leukemic agents, relative to mirna-16 or mirna-15.

Conclusion

Our study suggests that the suppression of mcl-1 and bcl-2 by mirna-15 and 16 can trigger apoptosis and overcome drug resistance of cll tumor cells. therefore, mirna-15 and 16 may be an effective adjuvant in cll chemotherapy.

Keywords

Mcl-1, bcl-2, mirna-15, mirna-16, fludarabin, abt-199