Up-Regulation of Epidermal Growth Factor-Receptors (EGF-R) by Nicotine in Cervical Cancer Cell Lines: This Effect May Be Mediated by EGF


Address reprint requests to Rajesh S. Mathur, Department of Obstetrics and Gynecology, Medical University of South Carolina, Suite 634, 96 Jonathan Lucas Street, Charleston, SC 29425

E-mail: mathurs@musc.edu


PROBLEM: Over-expression of epidermal growth factor-receptors (EGF-R) has been described in a variety of cancers, including cervical cancer. Nicotine may increase cellular proliferation rates through a mechanism involving EGF or EGF-R. In this study, we ascertain the effect of EGF antibodies on nicotine-enhanced proliferation rates in two cervical cancer cell lines.
METHOD OF STUDY: We studied (a) nicotine-induced increase in the cellular expression of EGF-R in human papillomavirus (HPV)-positive ME-180 and HPV-negative HT-3 cervical cancer cell line cultures, using a semi-quantitative immunofluorescent antibody assay; (b) alterations in cellular proliferation in association with changes in EGF-R levels; and (c) the EGF-R mediation by EGF.
RESULTS: Nicotine exposure at physiologically attainable plasma concentrations caused increased expression of EGF-R in both cervical cancer cell lines. Up-regulation of EGF-R was associated with increased cellular proliferation. Decreased expression of EGF-R was associated with decreased cellular proliferation. These data were consistent with EGF-R expression as a mechanism for the control of proliferation of the cervical cancer cells. The action of nicotine was abrogated when antibodies to EGF were added, implying that nicotine up-regulation of EGF-R may be mediated by EGF.
CONCLUSIONS: Our data show that nicotine-induced proliferation of cervical cancer cells is mediated through EGF-R over-expression and that this action of nicotine utilizes EGF.