Trichostatin A up-regulates coxsackievirus-adenovirus receptor (CAR) expression through inhibiting MAPK/ERK pathway to enhance the antitumor activity of H101 virus in thymic carcinoma / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the expression of coxsackievirus-adenovirus receptor (CAR) in thymic carcinoma and the relationship between CAR and the antitumor activity of oncolytic adenovirus H101.Methods:The expression of CAR in thymic carcinoma tissues and cells were detected by RT-qPCR and Western blot. H101 expression and virus titers in Bcap-37, MP59 and T1889 cells after infection were detected by RT-qPCR and 50% tissue culture infectious dose (TCID 50). The proliferation activity and apoptosis rates of T1889 cells infected with H101 at different multiplicity of infection (MOI) were detected by CCK-8 and flow cytometry. CAR expression in T1889 cells treated with different concentrations of trichostatin A (TSA), a histone deacetylase inhibitor, was detected. H101 expression and virus titers in the TSA-treated and H101-infected cells were detected. Cell activity was detected by CCK-8. The phosphorylation levels of MARK and ERK1/2 and the expression of CAR at protein level in TSA-treated or TSA+ TBHQ (ERK activator) treated cells were detected. Results:CAR expression at both mRNA and protein levels were significantly lower in thymic carcinoma tissues than in adjacent normal tissues ( P<0.01), and lower in MP59 and T1889 cells than in thymic epithelial cells (TEC) and Bcap-37 cells ( P<0.01). H101 expression in MP59 and T1889 cells and the titers of H101 in culture supernatants were significantly lower than those in Bcap-37 cells ( P<0.01). Compared with Bcap-37 cell, the activity of MP59 and T1889 cells was significantly increased and the apoptosis rates were significantly decreased 48 h after H101 infection ( P<0.01). The expression of CAR at both mRNA and protein levels in T1889 cells treated with different concentrations of TSA increased in a dose-dependent manner. When T1889 cells were treated with 0.25 μmol/L of TSA, the expression of H101 at mRNA level and H101 titers were significantly increased ( P<0.05); the phosphorylation levels of MAPK and ERK1/2 proteins were continuously decreased; the expression of CAR was continuously increased. Compared with the TSA treatment group, the expression of CAR at protein level in the TSA+ TBHQ treatment group decreased significantly ( P<0.01), and the p-ERK1/2/ERK1/2 ratio increased significantly ( P<0.01). Conclusions:TSA could up-regulate CAR expression in thymic carcinoma by inhibiting the MARK/ERK1/2 pathway, thereby enhancing the antitumor activity of H101.