Objective   To explore the effect of histone deacetylase (HDAC) inhibitor

trichostatin A (TSA)

on the expression of Coxsackie and adenovirus receptor (CAR) in esophageal cancer cell line EC9706.    Methods   Immunocytochemistry

RT-PCR and Western blotting were used to detect the expression of CAR in EC9706 cells

and its mRNA and protein expressions after the treatment of 0.5 mol/L TSA for 12

24 and 48 h were also studied. Transfection efficiency of virus Ad-GFP in the EC9706 cells with or without 0.5 mol/L TSA treatment was determined by flow cytometry. Anti-tumor effect of adenovirus carrying thymidine kinase (Ad-TK) was evaluated by MTT assay.    Results   After 0.5 μmol/L TSA treatment for 12

24 and 48 h

CAR mRNA and protein expression were 0.44±0.01 and 0.37±0.02

0.66±0.04 and 0.58±0.01

and 0.77±0.05 and 0.70±0.03 respectively. Compared to those of control group (0.27±0.02 and 0.22±0.03)

the CAR mRNA and protein expressions were significantly increased in EC9706 cells after TSA treatment (P0.05

0.01)

and the expressions showed a time-dependent manner. Flow cytometry indicated that the transfection efficiency was (1.35±0.11)% in the EC9706 cells

but was (2.58±0.17)%

(4.96±0.14)%

and (6.36±0.15)% respectively in the cells after 0.5 μmol/L TSA treatment for 12

24 and 48 h. MTT results showed that the Ad-TK-mediated cytotoxicity in the cells with 0.5 μmol/L TSA treatment for 48 h was eight times higher than in the cells untreated.    Conclusion   TSA can increase gene transfer efficiency of adenovirus into cancer cells by upregulating CAR.