| Objective:Esophageal carcinoma (EC) is one of the high incidence carcinomas in malignant tumors of our country. The mortality of esophageal carcinoma is the fourth. It has been known that combined biological effects of multiple factors are involved in the carcinogenesis of esophageal epithelium. The morbidity of esophageal carcinoma is still in a relative high level. It is difficult to eradicate or block the carcinogen harmful to the people through improving the environment or getting to a good dietary habit. Therefore, it is necessary to look for an potential chemopreventive pathway or drugs to lower the risk of carcinogenesis of esophageal epithelial cells.Recent epidemiological studies indicate that regular intake of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the risk of gastrointestinal tract carcinomas such as colorectal carcinoma, esophageal carcinoma, etc. NSAIDs are the inhibitors of cyclooxygenase (COX). Data above indicated that COX may play an important role in the oncogenesis of esophagus. Up to now, few studies have been reported about it.The aim of this study was to investigate the role of COX in the carcinogenesis of esophageal epithelial cells of high-risk area of EC. First, the expression of COX in the esophageal epithelial cells was detected. COX may be a new potential chemopreventive target of EC. Secondly, tissue samples of EC were collected from Hebei Provincial Tumor Hospital and used to investigate the effect of COX in the EC and the relationship between the expression of COX and cell proliferation regulatory genes.Thirdly, to elucidate the biological effects of different NSAIDs and probable mechanism on squamous cell carcinoma (SCC) cells, in the present study, three esophageal squamous carcinoma cell lines were used to detect the effect of aspirin, indomethacin and NS-398 on the proliferation and apoptosis as well as apoptotic related genes, respectively. These results suggested that NSAIDs may be the agents for the chemoprevention of EC in the high risk regions. The EC in China has obvious geographical characteristics. This provided the good basis of chemoprevention by NSAIDs.Methods:1 Studies on the exfoliated esophageal epithelial cellsThe exfoliated cells collected by esophageal abrasive balloon were smeared, stained with Papanicolaou's technique, and diagnosed by two pathologists, respectively. DNA content, ploidy and cell cycle of the epithelial cells were detected by flow cytometry(FCM).On the same time, expressions of COX-1, COX-2, p53, p21/WAF1, p16, cyclin D1 and CDK4 labeled by indirect immunofluorescence were detected by FCM, respectively.2 Studies on the esophageal squamous cell carcinomaFresh tissue samples were collected from 81 patients with SCC of the esophagus who underwent esophagectomy. The specimens were fixed in 4% buffered paraformaldehyde/0.1M PBS(pH 7.2)(containing 0.1% DEPC) for 3 hours, dehydrated, embedded in paraffin, sectioned, and stained with H&E. Tumor type and the grade of tumor differentiation were determined by two experienced pathologists, respectively. The expressions of COX-1, COX-2, iNOS and bcl-2 mRNA were detected by in situ hybridization (ISH), and expressions of COX-1 and Bax protein were detected by immunohistochemistry (IHC). Specimens collected at the same site were fixed in 70% cold alcohol. The expressions of COX-1, COX-2, iNOS, bcl-2, PCNA, cyclin D1, cyclin E, CDK4 and p27 protein were detected by FCM, respectively. The positive signals of results of ISH and IHC on the slideswere measured by Color Pathological Image Analysis System.3 Cell culture of ECEca-109, TTN and TE-13 are permanent cell lines derived from squamous cell carcinomas of the esophagus, and they were maintained in RPMI1640 supplemented with FBS(10%), penicillin (100 units/ml) and streptomycin (100 units/ml). The effects of aspirin, indomethacin and NS-398 on three cell lines were observed respectively. Morphological changes were observed under inverted microscope. The inhibition effect of cel...
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