Abstract: Objective To verify the hypothesis that aspirin,a non-selective COX-2 inhibitor,could induce apoptosis in ESCC cell lines and to evaluate the effects of cigarette smoking extracts on proliferation and apoptosis in ESCC cell lines.In addition,it is developed that the interaction between cigarette smoke extracts and NSAIDs on ESCC cell lines.Methods The apoptosis was determined by flow cytometry.MTT assay was performed to study the effect of cigarette smoking extracts on esophageal cancer cell growth.Results Aspirin was found to be able to induce the apoptosis of EC109 cell,and the apoptosis was dose and time dependent.Results showed that the proliferation of EC109 cell lines were promoted by CE(1～40 mg/L),EE(10～80 mg/L) and NNK(0.01～10 mmol/L) in 24 h.The proliferation of cell lines were inhibited by aspirin.Both CE and NNK could inhibit the apoptosis that was induced by aspirin.EE has no similar effects on the apoptosis.Conclusion Aspirin could inhibit the proliferation of EC109 cell by inducing the apoptosis,cigarette smoking extracts could inhibit the apoptosis that was induced by aspirin.It is suggested that the effects of cigarette smoking extracts on cell proliferation is related to COX-2.

Key words: esophageal squamous cell carcinoma, cyclooxygenase-2, non-steroidal anti-inflammatory drugs, cigarette smoking extracts, apoptosis