Abstract: Objective To investigate the influence of cigarette ethanol extraction(EE) and nuclear factor of kappa B(NF-κB) inhibitor, pyrrolidine dithiocarbamate(PDTC), on the constitutive NF-κB activity. Methods EE were incubated with two esophageal squamous cell carcinoma(ESCC) cell lines for 24 h respectively, which were pretreated with or without PDTC, proliferation rate was measured by MTT, apoptosis rate was measured by AnnexinV+PI, NF-κB activity by electrophoretic mobility shift assay(EMSA). Expression of NF-κB and the correlation between smoking were investigated in ESCC specimens from 49 cases by immunohistochemistry. Results PDTC(25~200 μg/ml) inhibited both ESCC cell lines proliferation in a dose-dependent manner. Cell proliferation was increased and cell apoptosis was inhibited by EE in a dose-dependent manner in both ESCC cell lines. EE could induce stimulation on NF-κB activity in both ESCC cell lines. The positive rate of NF-κB expression in specimens of human ESCC was 79.59%. The positive rate of NF-κB expression was higher for smokers compared to nonsmokers. Conclusion EE was shown to be a positive regulator of the activation of the NF-κB pathway in ESCC cell lines. PDTC, a specific inhibitor of NF-κB, can block the effect of EE. NF-κB is activated in ESCC tissue, cigarette smoking may be strongly associated with NF-κB activation.

Key words: esophageal squamous cell carcinoma, nuclear factor of kappa B, smoke