The novel HDAC inhibitor NDACI054 sensitizes human cancer cells to radiotherapy.


The novel HDAC inhibitor NDACI054 sensitizes human cancer cells to radiotherapy.

Hehlgans, S.; Storch, K.; Lange, I.; Cordes, N.

BACKGROUND AND PURPOSE:

Inhibition of histone deacetylases (HDACs) has preclinically and clinically shown promise to overcome radio- and chemoresistance of tumor cells. NDACI054 is a novel HDAC inhibitor, which has been evaluated here for its effects on cell survival and radiosensitization of human tumor cell lines from different origins cultured under more physiological three-dimensional (3D), extracellular matrix (ECM)-based conditions.

MATERIAL AND METHODS:

A549 lung, DLD-1 colorectal, MiaPaCa2 pancreatic and UT-SCC15 head and neck squamous cell carcinoma cells were treated with increasing NDACI054 concentrations (0-50 nM, 24 h) either alone or in combination with X-rays (single dose, 0-6 Gy). Subsequently, 3D clonogenic cell survival, HDAC activity, histone H3 acetylation, apoptosis, residual DNA damage (γH2AX/p53BP1 foci assay 24h post irradiation) and phosphorylation kinetics of Ataxia telangiectasia mutated (ATM), DNA-dependent protein kinase (DNA-PK), Caspase-3 and Poly(ADP-ribose)-Polymerase 1 (PARP 1) cleavage were analyzed.

RESULTS:

NDACI054 potently decreased HDAC activity with concomitant increase in acetyl-histone H3 levels, mediated significant cytotoxicity and radiosensitization. These effects were accompanied by a significant increase of residual γH2AX/p53BP1-positive foci, slightly elevated levels of Caspase-3 and PARP 1 cleavage but no induction of apoptosis.

CONCLUSIONS:

Our data show potent antisurvival and radiosensitizing effects of the novel HDAC inhibitor NDACI054 encouraging further preclinical examinations on this compound for future clinical use.

Keywords: 3D cell culture; Cancer cell lines; DNA repair; HDAC inhibitor; Ionizing radiation

Permalink: https://www.hzdr.de/publications/Publ-19902
Publ.-Id: 19902