Effects of 17beta-Estradiol and Estrogen Receptor Antagonists on the Proliferation of Gastric Cancer Cell Lines

ABSTRACT

PURPOSE: The aims of this study were as follow 1) to de scribe the expression status of estrogen receptor-alpha and -beta mRNAs in five gastric carcinoma cell lines; 2) to evaluate in vitro the effects of 17beta-estradiol and estrogen receptor antagonists on the proliferation of the cell lines. MATERIALS AND METHODS: Detection of estrogen receptor-alpha and estrogen receptor-beta mRNA in five human gastric cancer cell lines (AGS, KATO III, MKN28, MKN45 and MKN74) was made by the reverse transcription-polymerase chain reaction system. To evaluate the effect of 17beta-estradiol and estrogen receptor antagonists on the proliferation of gastric cancer cell line, the cell lines which expressed both es trogen receptors were chosen and treated with 17beta-estradiol and estrogen receptor antagonists (methyl-piperidino-pyrazole and pyrazolo [1,5-a] pyrimidine). Cell proliferation was assessed with the methylthiazol tetrazolium test. RESULTS: Estrogen receptor-alpha and estrogen receptor-beta mRNAs were expressed in three (KATO III, MKN28 and MKN45) and all of the five gastric cancer cell lines, respectively. At higher concentrations, 17beta-estradiol inhibited cell growth of MKN28, MKN45 and KATO III cell lines. Neither estrogen receptor-alpha nor estrogen receptor-beta antagonist blocked the anti-proliferative effect of 17beta-estradiol. CONCLUSIONS: Our results indicate that estrogen receptor-beta mRNAs are preferentially expressed in gastric cancers and also imply that hormone therapy rather than estrogen receptor blockers may be a useful strategy for the treatment of estrogen receptor-beta positive gastric cancer. Its therapeutic significance in gastric cancer are, however, limited until more evidence of the roles of estrogen receptors in the gastric cancer are accumulated.