HDAC Inhibition Induces MicroRNA-182, which Targets RAD51 and Impairs HR Repair to Sensitize Cells to Sapacitabine in Acute Myelogenous Leukemia.

Abstract

PURPOSE:

The double-strand breaks elicited by sapacitabine, a clinically active nucleoside analogue prodrug, are repaired by RAD51 and the homologous recombination repair (HR) pathway, which could potentially limit its toxicity. We investigated the mechanism by which histone deacetylase (HDAC) inhibitors targeted RAD51 and HR to sensitize acute myelogenous leukemia (AML) cells to sapacitabine.

EXPERIMENTAL DESIGN:

Chromatin immunoprecipitation identified the role of HDACs in silencing miR-182 in AML. Immunoblotting, gene expression, overexpression, or inhibition of miR-182 and luciferase assays established that miR-182 directly targeted RAD51. HR reporter assays, apoptotic assays, and colony-forming assays established that the miR-182, as well as the HDAC inhibition-mediated decreases in RAD51 inhibited HR repair and sensitized cells to sapacitabine.

RESULTS:

The gene repressors, HDAC1 and HDAC2, became recruited to the promoter of miR-182 to silence its expression in AML. HDAC inhibition induced miR-182 in AML cell lines and primary AML blasts. miR-182 targeted RAD51 protein both in luciferase assays and in AML cells. Overexpression of miR-182, as well as HDAC inhibition-mediated induction of miR-182 were linked to time- and dose-dependent decreases in the levels of RAD51, an inhibition of HR, increased levels of residual damage, and decreased survival after exposure to double-strand damage-inducing agents.

CONCLUSIONS:

Our findings define the mechanism by which HDAC inhibition induces miR-182 to target RAD51 and highlights a novel pharmacologic strategy that compromises the ability of AML cells to conduct HR, thereby sensitizing AML cells to DNA-damaging agents that activate HR as a repair and potential resistance mechanism. Clin Cancer Res; 22(14); 3537-49. ©2016 AACR.

• Authors: Tsung-Huei Lai, Brett Ewald, Alma Zecevic, Chaomei Liu, Melanie Sulda, Dimitrios Papaioannou, Ramiro Garzon, James S Blachly, William Plunkett, Deepa Sampath
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 22 Issue 14 Pg. 3537-49 (07 15 2016) ISSN: 1557-3265 [Electronic] United States
• PMID: 26858310 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: ©2016 American Association for Cancer Research.

Chemical References

• Arabinonucleosides
• Histone Deacetylase Inhibitors
• MicroRNAs
• Mirn182 microRNA, human
• Cytosine
• Rad51 Recombinase
• HDAC1 protein, human
• HDAC2 protein, human
• Histone Deacetylase 1
• Histone Deacetylase 2
• Histone Deacetylases
• sapacitabine

Topics

• Apoptosis (drug effects, genetics)
• Arabinonucleosides (pharmacology)
• Cell Line, Tumor
• Cytosine (analogs & derivatives, pharmacology)
• DNA Damage (drug effects, genetics)
• Gene Expression (drug effects, genetics)
• HeLa Cells
• Histone Deacetylase 1 (antagonists & inhibitors)
• Histone Deacetylase 2 (antagonists & inhibitors)
• Histone Deacetylase Inhibitors (pharmacology)
• Histone Deacetylases (metabolism)
• Humans
• Leukemia, Myeloid, Acute (drug therapy, genetics, metabolism)
• MicroRNAs (genetics)
• Promoter Regions, Genetic (drug effects, genetics)
• Rad51 Recombinase (genetics)
• Recombinational DNA Repair (drug effects)