Panobinostat enhances olaparib efficacy by modifying expression of homologous recombination repair and immune transcripts in ovarian cancer.

We have previously shown that histone deacetylase inhibitors (HDACi) downregulate expression of several key genes involved in homologous recombination (HR) DNA repair, which sensitizes ovarian cancer cells proficient in HR to DNA damage induction by PARP inhibitors (PARPi), leading to cell death. The goals of the study were to characterize the transcriptional changes on a genome-wide scale induced by the combination of the HDACi panobinostat and PARPi olaparib in ovarian cancer cells to 1) investigate if downregulation of HR genes is a co-ordinated response to HDACi and PARPi and 2) identify other cellular pathways regulated by HDACi and PARPi.