1. Synergistic Cytotoxicity of Histone Deacetylase and Poly-ADP Ribose Polymerase Inhibitors and Decitabine in Breast and Ovarian Cancer Cells: Implications for Novel Therapeutic Combinations.
- Author
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Valdez BC, Tsimberidou AM, Yuan B, Baysal MA, Chakraborty A, Andersen CR, and Andersson BS
- Subjects
- Humans, Female, Cell Line, Tumor, Vorinostat pharmacology, Panobinostat pharmacology, Apoptosis drug effects, Antineoplastic Combined Chemotherapy Protocols pharmacology, Hydroxamic Acids pharmacology, MCF-7 Cells, Decitabine pharmacology, Drug Synergism, Histone Deacetylase Inhibitors pharmacology, Ovarian Neoplasms drug therapy, Ovarian Neoplasms metabolism, Ovarian Neoplasms pathology, Phthalazines pharmacology, Poly(ADP-ribose) Polymerase Inhibitors pharmacology, Breast Neoplasms drug therapy, Breast Neoplasms pathology, Breast Neoplasms metabolism, Cell Proliferation drug effects, Piperazines pharmacology
- Abstract
Breast and ovarian cancers pose significant therapeutic challenges. We explored the synergistic cytotoxicity of histone deacetylase inhibitors (HDACis), poly(ADP-ribose) polymerase inhibitors (PARPis), and decitabine in breast (MDA-MB-231 and MCF-7) and ovarian (HEY-T30 and SKOV-3) cancer cell lines that were exposed to HDACi (panobinostat or vorinostat), PARPi (talazoparib or olaparib), decitabine, or their combinations. HDACi, PARPi, and decitabine combinations had synergistic cytotoxicity (assessed by MTT and clonogenic assays) in all cell lines (combination index < 1). Clonogenic assays confirmed the sensitivity of breast and ovarian cancer cell lines to the three-drug combinations (panobinostat, talazoparib, and decitabine; panobinostat, olaparib, and decitabine; vorinostat, talazoparib, and decitabine; vorinostat, olaparib, and decitabine). Cell proliferation was inhibited by 48-70%, and Annexin V positivity was 42-59% in all cell lines exposed to the three-drug combinations. Western blot analysis showed protein PARylation inhibition, caspase 3 and PARP1 cleavage, and c-MYC down-regulation. The three-drug combinations induced more DNA damage (increased phosphorylation of histone 2AX) than the individual drugs, impaired the DNA repair pathways, and altered the epigenetic regulation of gene expression. These results indicate that HDACi, PARPi, and decitabine combinations should be further explored in these tumor types. Further clinical validation is warranted to assess their safety and efficacy.
- Published
- 2024
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