Effect of Sterols Isolated fromMyrtillocactus geometrizanson Growth Inhibition of Colon and Breast Cancer Cells

Abstract

Objective. To explore the effect of peniocerol and macdougallin on HCT-15 and MCF-7 cells proliferation, cell cycle, apoptosis, and PARP cleavage.Methods. HCT-15 and MCF-7 cells were treated with various concentrations of peniocerol and macdougallin (10–80 μM) during 24 or 48 h. Crystal Violet Assay was used to evaluate the inhibition effect. Cell cycle regulation was examined by a propidium iodide method. Cell apoptosis was detected through both Annexin–V FLUOS/PI double-labeled cytometry assays and Western blot was applied to assess PARP cleavage.Results. Peniocerol and macdougallin induced growth inhibition and apoptosisin vitroin a time- and dose-dependent manner. Moreover, peniocerol and macdougallin induced arrest of cell cycle-dependent manner and increased the proportion of cells in G0/G1phase. PARP cleavage in HCT-15 and MCF-7 cells was induced by treatment with peniocerol and macdougallin after 36 hours.Conclusions. Our results showed that the mechanism of cytotoxicity displayed by peniocerol and macdougallin is related to cell cycle arrest and apoptosis in both cell lines. This is a significant observation because it helps to understand the way some oxysterols isolated fromMyrtillocactus geometrizansdevelop their biological activities against cancer cells.