Epigenetic alterations of the histone acetylation play an important role in the 
regulation of gene expression associated with cell cycles and apoptosis that may 
affect the chemosensitivity of gastric carcinomas. Recently, a histone 
deacetylase inhibitor, trichostatin A (TSA), was proven to be a chemo-sensitizer 
on human erythroleukemia cells. With the aim of improving the chemotherapeutic 
efficacy of gastric carcinoma, the effect of TSA on the chemosensitivity of 
several anticancer drugs in gastric carcinoma cells was investigated. Human 
gastric cancer cell lines, OCUM-8 and MKN-74, and 5 anticancer drugs, 
5-fluorouracil (5-FU), paclitaxel (PTX), oxaliplatin (OXA), irinotecan (SN38) 
and gemcitabine (GEM) were used. In both gastric cancer cell lines, a 
synergistic anti-proliferative effect by the combination of TSA (30 ng/ml) with 
5-FU, PTX or SN38 showed a synergistic anti-proliferative effect in OCUM-8 and 
MKN-74 cells. TSA increases the expression of p21, p53, DAPK-1 and the DAPK-2 
gene in both OCUM-8 and MKN-74 cells. In conclusion, TSA is a promising 
chemotherapeutical agent in combination with anticancer drugs of 5-FU, PTX and 
SN38 in gastric cancer cell lines. The up-regulation of p53, p21, DAPK-1 and 
DAPK-2 might be associated with the synergistic effect of TSA.