4β-Hydroxywithanolide E induces human breast cancer MCF-7 cell apoptosis through oxidative stress and DNA damage

• Main Authors: Fei-Ching Chang, 張斐淨
• Other Authors: Hong-Zin Lee
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/88719048364279881070

碩士 === 中國醫藥大學 === 藥學系碩士班 === 100 === 4β-Hydroxywithanolide E, an active component from Physalis peruviana, was found to have anti-breast cancer cytotoxicity, but the mechanism still need to be further discovered. In this study, we found that 4β-hydroxywithanolide E-induced human breast cancer MCF-7 cell apoptosis is irreversible and the caspase-9 pathway is involved in the 4β-hydroxywithanolide E-induced cell death. We also investigated the role of oxidative stress in 4β-hydroxywithanolide E-induced MCF-7 cell apoptosis. Exposure of MCF-7 cells to 4β-hydroxywithanolide E caused production of reactive oxygen species and a significant increase in antioxidative enzymes activity, such as superoxide dismutase (SOD) and catalase. Glutathione or N-acetylcysteine significantly inhibited the 4β-hydroxywithanolide E-triggered activity of the radical-scavenging enzymes and cell death. The 4β-hydroxywithanolide E-induced cell cycle arrest at G0/G1- and S-phase, changes in cell cycle regulators expression and microtubule distribution were reversed by pretreatment with glutathione or N-acetylcysteine in MCF-7 cells. In addition, glutathione or N-acetylcysteine selectively inhibited the 4β-hydroxywithanolide E-induced DNA damage and changes in the protein expression of DNA damage sensors and repair enzymes such as ATM (S1981), ??-H2AX, 53BP1, BRCA1, chk2 and XRCC4 in MCF-7 cells. We also found that MAP kinase, ubiquitin-conjugated protein degradation and cAMP pathways were not important determinants of apoptotic death induced by 4β-hydroxywithanolide E in MCF-7 cells.