Histone Deacetylase Inhibitors Enhance Paclitaxel-induced Cell Death in Ovarian Cancer Cell Lines Independent of p53 Status

Background: Recurrence of drug-resistant disease contributes to the high mortality of ovarian cancer patients, which necessitates the identification of additional chemotherapeutic drugs. Histone deacetylase inhibitors (HDAIs) induce apoptosis in a number of malignant cell types and may represent a new class of drugs clinically relevant in the treatment of ovarian cancer. Materials and Methods: Ovarian cancer cells were treated with various combinations of a HDAI and paclitaxel (PTX). Cell death was measured using annexin V / propidium iodide exclusion. Results: The PTX/HDAI drug combination was as efficient in inducing cell death as continuous PTX treatment and superior to continuous HDAI treatment. Reversing the sequence of drug exposure reduced the cytotoxic efficacy of the drug combination. The p53 status of the cell lines did not alter the cytotoxic efficacy of the treatment protocols. Conclusion: These results suggest that HDAIs possess possible clinical applications as an adjuvant therapy in the treatment of ovarian cancer.