Selective cytotoxicity of Saururus chinensis in glucose-deprived HT-29 human colon cancer cells

Abstract

In this study, the selective cytotoxic activity of methanolic extracts of Saururus chinensis (SCE) was examined on glucose-deprived HT-29 cells. The effects of SCE on 2-deoxy-glucose (2DG) or glucose-free stressed HT-29 cells were evaluated through the MTT reduction assay, morphological observations, and the colony formation assay, in which SCE (5, 10 μg/mL) was found to be highly toxic to HT-29 cells only during glucose-deprived conditions. In addition, the mechanism of selective cytotoxic effects on SCE was assessed by Western blot analysis; SCE suppressed the accumulation of GRP78. Furthermore, apoptotic effects of SCE on glucose-deprived HT-29 cells were identified by Hoechst 33342 staining and flow cytometric analysis. In conclusion, SCE induced apoptosis in HT-29 cells under glucose-deprived conditions by down-regulation of GRP78. Cytotoxic effects on HT-29 cells were only observed during glucose deprivation, suggesting that SCE may be a target for novel therapeutic agents for treating colon cancer under glucose-deprived stress.