Silibinin induced autophagic and apoptotic cell death in HT1080 cells through a reactive oxygen species pathway.
Hepatoprotectant silibinin has anticancer and chemo-preventive effects. In this study, silibinin showed significant inhibitory effect on human fibroblast HT 1080 cell growth cultured in media containing 10% fetal bovine serum or in serum free media, and in the latter case, silibinin exerted a more significant effect. Silibinin induced autophagy at 12 h, confirmed by monodansylcadervarine (MDC) staining, up-regulation of Beclin 1 (initiation factor for autophagosome formation), and conversion of LC3 I to LC3 II (autophagosome marker). It also induced apoptosis at 24 h, proved by observation of apoptotic body and activation of caspase-3. 3-Methyladenine (3-MA) inhibited silibinin-induced autophagy and promoted cell survival, suggesting that autophagy enhanced silibinin-induced apoptosis in HT1080 cells. Silibinin generated reactive oxygen species (ROS) in HT1080 cells, and the ROS scavenger N-acetylcysteine (NAC) reversed the cytotoxicity of silibinin, resulting in cell survival by inhibition of autophagic and apoptotic pathways. Application of specific antioxidants demonstrated that H(2)O(2) was a major factor in silibinin-induced ROS since the H(2)O(2) scavenger catalase reduced both autophagy and cell death. O(2)*(-) also contributed to silibinin-induced cell death.
Duan
Wenjun
W
China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, China.
Jin
Xiaoying
X
Li
Qisheng
Q
Tashiro
Shin-ichi
S
Onodera
Satoshi
S
Ikejima
Takashi
T
D000111:Acetylcysteine / Q000494:pharmacology; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D002460:Cell Line; D016895:Culture Media, Serum-Free; D004347:Drug Interactions; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D000077385:Silybin; D012838:Silymarin / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D000975:Antioxidants; D016895:Culture Media, Serum-Free; D017382:Reactive Oxygen Species; D012838:Silymarin; D000077385:Silybin; C025946:3-methyladenine; D006861:Hydrogen Peroxide; D000225:Adenine; D000111:Acetylcysteine