Discussion
We confirmed that EZH2i and TSA have positive effects on the osteogenic differentiation of DPSCs. EZH2i activates the expression of key regulatory genes (RUNX2, BMP2, and ALPL) directly, whereas TSA interacts with signalling pathways induced by supplements in OIM to activate these genes.
Objective
Epigenetic mechanisms play regulatory roles in dental pulp stem cell (DPSC) differentiation. The molecules that modulate these mechanisms can be used to enhance DPSC differentiation in experimental studies and clinical applications. We investigated the combined effects of an epigenetic modulator enhancer of zeste homologue 2 inhibitor (EZH2i), trichostatin A (TSA), and 5-azacytidine (5-AZA) on the osteogenic differentiation of DPSCs.
Results
To assess osteogenic differentiation, we measured alkaline phosphatase activity, calcium deposition, and expression of osteogenic differentiation marker genes (RUNX2, BMP2, and ALPL) after 7 or 21 days of combinatorial drug treatment in normal cell culture medium or osteo-inductive medium (OIM). No synergistic effects were observed for any possible combination of EZH2i, TSA, or 5-AZA. However, the effects of these drugs and their combinations depend on the time and culture conditions.