Abstract
Currently, the effects of various bioactive compounds on Histone Deacetylase (HDAC) enzyme activity are being investigated. In this context, the aim of this study was to examine the effect of Piperlongumine (PL) on HDAC enzyme activity in HeLa and HEK293T cells in vitro. The IC₅₀ doses of PL for HeLa and HEK293T cell lines were determined using MTT and AO/PI staining methods. HDAC activity was measured using a commercial kit in lysates obtained via the NETN lysis method from cells treated with IC₅₀ doses of PL for 24 and 48 hours in vitro. Additionally, HDAC activity was assessed in lysates from cells cultured under normal conditions and directly treated with IC₅₀ doses of PL immediately before the HDAC assay. After 24- and 48-hour PL treatments, a statistically significant increase in HDAC activity was observed in HEK293T cells, whereas a non-significant increase was found in HeLa cells. In lysates directly treated with PL, HDAC activity significantly increased in HeLa cells but showed no significant change in HEK293T cells. These findings suggest that PL may affect HDACs via distinct mechanisms depending on cell type. The significant increase in HDAC activity upon direct treatment of HeLa lysates suggests a possible physical interaction between PL and HDACs in cancer cells. Conversely, the increased HDAC activity observed in HEK293T cells following 24- and 48-hour in vitro PL treatment implies that PL may act in normal cells through indirect and delayed pathways.