Chloroform extract of cigarette smoke induces proliferation of human esophageal squamous-cell carcinoma cells: Modulation by β-adrenoceptors

Abstract

The present study aimed to delineate the actions of cigarette smoke extracts on esophageal squamous-cell carcinoma cell growth in vitro. Both chloroform- and ethanol-extracts from cigarette smoke stimulated human esophageal squamous carcinoma EC109 cell proliferation. Chloroform- and ethanol-extracts also upregulated β-adrenoceptors expression in EC109 cells. Cyclo-oxygenase-2 (COX-2) expression was increased by chloroform-extract. The stimulatory actions of chloroform-extract on cell proliferation and COX-2 expression were abolished by β₁- and β₂-adrenoceptor selective antagonists, implicating that COX-2 was downstream to the β-adrenoceptors. Collectively, the promoting action of chloroform-extract from cigarette smoke on esophageal squamous-cell carcinoma cell proliferation is β-adrenoceptor- and COX-2-dependent.

Keywords::

• β-adrenoceptors
• cigarette smoke extract
• cyclo-oxygenase-2
• esophageal cancer

Acknowledgments

The study was supported by the Hong Kong Research Grants Council (CUHK 7499/05M) and the Direct Grant from the Chinese University of Hong Kong.

Declaration of interest: The authors report no financial conflicts of interest. The authors alone are responsible for the content and writing of this paper.