Mechanism of autophagy induction and role of autophagy in antagonizing mitomycin C-induced cell apoptosis in silibinin treated human melanoma A375-S2 cells.
The aim of this study was to elucidate the molecular mechanisms mediating silibinin-induced autophagy in A375-S2 cells. In the present study it was found that silibinin-induced autophagy through increasing the conversion of LC3 I to LC3 II and up-regulating Beclin-1 expression, which was concomitant with p53 suppression and NF-κB activation. P53 inhibitor, pifithrin-α (PFT-α), increased autophagy and enhanced the expression of NF-κB. Moreover, inducing p53 accumulation with MG132 reduced autophagic ratio, and repressed the expression and activation of NF-κB expression. NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC) suppressed autophagy. Autophagic specific inhibitor 3-methyladenine (3-MA) treatment reversed silibinin-induced p53 suppression as well as NF-κB activation, suggesting that there was a positive feedback loop between p53 inhibition-mediated NF-κB activation and autophagy. In addition, we also found that 3-MA efficiently abrogated silibinin's cyto-protective effect against mitomycin C-induced cell death, and reversed the suppressive efficacy of silibinin on p53 expression, suggesting that autophagy contributed to silibinin's cyto-protective effect against mitomycin C-induced cell death in A375-S2 cells.
China-Japan Research Institute of Medical Pharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China.
Yuan-yuan
YY
Jiang
China-Japan Research Institute of Medical Pharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China.
Ri
R
Yang
China-Japan Research Institute of Medical Pharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China.
Hong-jun
HJ
Wang
China-Japan Research Institute of Medical Pharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China.
Huai
H
Huang
China-Japan Research Institute of Medical Pharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China.
Di
D
Wu
Department of Clinical and Biomedical Sciences, Showa Pharmaceutical University, Tokyo 194-8543, Japan.
Shin-ichi
S
Tashiro
Department of Clinical and Biomedical Sciences, Showa Pharmaceutical University, Tokyo 194-8543, Japan.
Satoshi
S
Onodera
China-Japan Research Institute of Medical Pharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, PR China.
Takashi
T
Ikejima
D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D008545:Melanoma / Q000473:pathology*; D016685:Mitomycin / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D016328:NF-kappa B / Q000378:metabolism; D011759:Pyrrolidines / Q000494:pharmacology; D000077385:Silybin; D012838:Silymarin / Q000494:pharmacology*; D013859:Thiocarbamates / Q000494:pharmacology; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D016328:NF-kappa B; D011759:Pyrrolidines; D012838:Silymarin; D013859:Thiocarbamates; D016159:Tumor Suppressor Protein p53; C020972:pyrrolidine dithiocarbamic acid; D000077385:Silybin; D016685:Mitomycin; C025946:3-methyladenine; D000225:Adenine