Synergistic effect of paeonol and cisplatin on oesophageal cancer cell lines

Background/aim. Paeonol, a phenolic component from the root bark of Paeonia moutan, has shown great promise in antitumour activities in our previous studies. The present study was designed to investigate whether paeonol has synergistic effect with cisplatin on the growth-inhibitory of human oesophageal cancer cell lines and the possible mechanism. Methods. Cell viabililty was measured by MTT assay. Drug-drug interactions were analysed by the coefficient of drug interaction. Apoptosis was detected by acridine orange fluorescence staining and flow cytometry assay. Bcl-2, Bax and caspase-3 expression was assayed by immunohistochemical staining. Results. A synergistic inhibitory effect on viability of the two cell lines was observed after combination of paeonol with various concentrations of cisplatin. Further study showed the combination induced greater apoptosis than the groups treated with paeonol or cisplatin alone. The expression of Bcl-2 was decreased and that of Bax was increased in treatment groups, especially in the combination group, with the ratio of Bcl-2/Bax decreased correspondingly. And the combination also resulted in greater activation of caspase-3 than did either agent alone. Conclusions. Paeonol, in combination with cisplatin, had a significantly synergistic growth-inhibitory effect on oesophageal cell line, which may be related to apoptosis induction. (c) 2008 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.