Induction of Apoptosis and Growth Inhibition of Cultured Human Endometrial Adenocarcinoma Cells (Sawano) by an Antitumor Lipoprotein Fraction of Rice Bran

Abstract

Objective. A lipoprotein fraction extracted from rice bran (RBF) has been proved to be nontoxic to normal cells and to possess the ability to derange energy metabolism and induce apoptosis in Ehrlich ascites tumor cells. This study is designed to investigate the therapeutic effects of RBF as an antitumor substance on endometrial adenocarcinoma cells (Sawano).Methods. Cultured human endometrial adenocarcinoma cells were treated with medium only (untreated), DMSO, or RBF at 100, 200, and 300 μg/ml. Mitotic indexes were counted by Giemsa stain and apoptotic index by fluorescent TUNEL stain for confocal laser scanning microscopy. DNA fragments were examined by agarose gel electrophoresis.Results. Characteristic apoptotic morphology was observed in Giemsa-stained cells and further confirmed by confocal laser scanning microscopy in RBF-treated cells. Growth of Sawano cells was inhibited by RBF in a dose- and time-dependent manner. Apoptotic indexes (AI) showed an increasing tendency, and mitotic indexes (MI) showed a downward tendency. In 300 μg/ml RBF-treated Sawano cells, AI even reached 41.62 ± 2.23% and MI decreased to 0.79 ± 0.08% at 96 h. Both showed significant differences from to controls and other RBF-treated groups. DNA agarose electrophoresis revealed DNA fragmentation in a ladder pattern.Conclusions. RBF can induce apoptosis of cultured human endometrial adenocarcinoma cells (Sawano) and inhibit its cell proliferation as an antitumor substance.