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Role of histone deacetylase inhibitor-induced reactive oxygen species and DNA damage in LAQ-824/fludarabine antileukemic interactions.

ABSTRACT: The role of reactive oxygen species (ROS) production on DNA damage and potentiation of fludarabine lethality by the histone deacetylase inhibitor (HDACI) LAQ-824 was investigated in human leukemia cells. Preexposure (24 h) of U937, HL-60, Jurkat, or K562 cells to LAQ-824 (40 nmol/L) followed by fludarabine (0.4 micromol/L) dramatically potentiated apoptosis (>or=75%). LAQ-824 triggered an early ROS peak (30 min-3 h), which declined by 6 h, following LAQ-824-induced manganese superoxide dismutase 2 (Mn-SOD2) upregulation. LAQ-824/fludarabine lethality was significantly diminished by either ROS scavengers N-acetylcysteine or manganese (III) tetrakis (4-benzoic acid) porphyrin or ectopic Mn-SOD2 expression and conversely increased by Mn-SOD2 antisense knockdown. During this interval, LAQ-824 induced early (4-8 h) increases in gamma-H2AX, which persisted (48 h) secondary to LAQ-824-mediated inhibition of DNA repair (e.g., down-regulation of Ku86 and Rad50, increased Ku70 acetylation, diminished Ku70 and Ku86 DNA-binding activity, and down-regulated DNA repair genes BRCA1, CHEK1, and RAD51). Addition of fludarabine further potentiated DNA damage, which was incompatible with cell survival, and triggered multiple proapoptotic signals including activation of nuclear caspase-2 and release of histone H1.2 into the cytoplasm. The latter event induced activation of Bak and culminated in pronounced mitochondrial injury and apoptosis. These findings provide a mechanistic basis for understanding the role of early HDACI-induced ROS generation and modulation of DNA repair processes in potentiation of nucleoside analogue-mediated DNA damage and lethality in leukemia. Moreover, they show for the first time the link between HDACI-mediated ROS generation and the recently reported DNA damage observed in cells exposed to these agents.

SUBMITTER: Rosato RR

PROVIDER: S-EPMC2586957 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature

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Role of histone deacetylase inhibitor-induced reactive oxygen species and DNA damage in LAQ-824/fludarabine antileukemic interactions.

Rosato Roberto R RR Almenara Jorge A JA Maggio Sonia C SC Coe Stefanie S Atadja Peter P Dent Paul P Grant Steven S

Molecular cancer therapeutics 20081001 10

The role of reactive oxygen species (ROS) production on DNA damage and potentiation of fludarabine lethality by the histone deacetylase inhibitor (HDACI) LAQ-824 was investigated in human leukemia cells. Preexposure (24 h) of U937, HL-60, Jurkat, or K562 cells to LAQ-824 (40 nmol/L) followed by fludarabine (0.4 micromol/L) dramatically potentiated apoptosis (>or=75%). LAQ-824 triggered an early ROS peak (30 min-3 h), which declined by 6 h, following LAQ-824-induced manganese superoxide dismutase ...[more]

PMID: 18852132

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Project description:Histone deacetylase inhibitors (HDACIs) activate the prosurvival nuclear factor-κB (NF-κB) pathway by hyperacetylating RelA/p65, whereas the chemopreventive agent resveratrol inhibits NF-κB by activating the class III histone deacetylase Sirt1. Interactions between resveratrol and pan-HDACIs (vorinostat and panobinostat) were examined in human acute myelogenous leukemia (AML) cells. Pharmacologically achievable resveratrol concentrations (25-50 μM) synergistically potentiated HDACI lethality in AML cell lines and primary AML blasts. Resveratrol antagonized RelA acetylation and NF-κB activation in HDACI-treated cells. However, short hairpin RNA Sirt1 knockdown failed to modify HDACI sensitivity, which suggests that factors other than or in addition to Sirt1 activation contribute to resveratrol/HDACI interactions. These interactions were associated with death receptor 5 (DR5) up-regulation and caspase-8 activation, whereas cells expressing dominant-negative caspase-8 were substantially protected from resveratrol/HDACI treatment, which suggests a significant functional role for the extrinsic apoptotic pathway in lethality. Exposure to resveratrol with HDACI induced sustained reactive oxygen species (ROS) generation, which was accompanied by increased levels of DNA double-strand breaks, as reflected in γH2A.X and comet assays. The free radical scavenger Mn(III)tetrakis(4-benzoic acid)porphyrin chloride blocked ROS generation, DR5 up-regulation, caspase-8 activation, DNA damage, and apoptosis, which indicates a primary role for oxidative injury in lethality. Analyses of cell-cycle progression and 5-ethynyl-2'-deoxyuridine incorporation through flow cytometry revealed that resveratrol induced S-phase accumulation; this effect was abrogated by HDACI coadministration, which suggests that cells undergoing DNA synthesis may be particularly vulnerable to HDACI lethality. Collectively, these findings indicate that resveratrol interacts synergistically with HDACIs in AML cells through multiple ROS-dependent actions, including death receptor up-regulation, extrinsic apoptotic pathway activation, and DNA damage induction. They also raise the possibility that S-phase cells may be particularly susceptible to these actions.

Dataset Information

Role of histone deacetylase inhibitor-induced reactive oxygen species and DNA damage in LAQ-824/fludarabine antileukemic interactions.

Publications

Role of histone deacetylase inhibitor-induced reactive oxygen species and DNA damage in LAQ-824/fludarabine antileukemic interactions.

Similar Datasets

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