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Inhibition on Proteasome β1 Subunit Might Contribute to the Anti-Cancer Effects of Fangchinoline in Human Prostate Cancer Cells.

Li D, Lu Y, Sun P, Feng LX, Liu M, Hu LH, Wu WY, Jiang BH, Yang M, Qu XB, Guo DA, Liu X - PLoS ONE (2015)

Bottom Line: The inhibitive effect of fangchinoline on caspase-like activity of proteasome was also observed in purified human erythrocyte 20S proteasome.Treatment of PC-3 tumor-bearing nude mice with fangchinoline inhibited tumor growth, induced apoptosis and also caused decrease in proteasome activities in tumor xenografts.Results of the present study suggested that proteasome inhibition was involved in the anti-cancer effects of fangchinoline.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China; Changchun University of Chinese Medicine, Changchun 130117, P.R. China.

ABSTRACT
Fangchinoline is a bisbenzylisoquinoline alkaloid isolated from Radix Stephaniae tetrandrae S. Moore. Fangchinoline and its structure analogue, tetrandrine, exhibited direct binding affinity with recombinant human proteasome β1 subunit and also inhibited its activity in vitro. In cultured prostate PC-3 cells and LnCap cells, fangchinoline could dose-dependently inhibit cell proliferation and caspase-like activity of cellular proteasome which was mediated by proteasome β1 subunit. The inhibitive effect of fangchinoline on caspase-like activity of proteasome was also observed in purified human erythrocyte 20S proteasome. In PC-3 cells, fangchinoline induced cell cycle arrest at G0/G1 phase and apoptosis. Treatment of PC-3 tumor-bearing nude mice with fangchinoline inhibited tumor growth, induced apoptosis and also caused decrease in proteasome activities in tumor xenografts. Dose-dependent and time-dependent accumulation of ubiquitinated proteins and important proteasome substrates such as p27, Bax and IκB-α were observed in fangchinoline-treated cells. Over-expression of proteasome β1 subunit by plasmid transfection increased sensitivity of cells to the cytotoxicity of fangchinoline while knockdown of proteasome β1 subunit ameliorated cytotoxicity of fangchinoline in PC-3 cells. Results of the present study suggested that proteasome inhibition was involved in the anti-cancer effects of fangchinoline. Fangchinoline and its structure analogues might be new natural proteasome inhibitors targeting β1 subunit.

No MeSH data available.


Related in: MedlinePlus

Inhibitive effects of fangchinoline on activity of purified human 20S proteasome.(A) Hydrolysis of the β1-specific fluorigenic peptide substrate Z-LLE-AMC at different concentrations by purified human 20S proteasome. (B) Time-dependent hydrolysis of 75 μM substrate Z-LLE-AMC by 20S proteasome with or without presence of 500 μM fangchinoline. (C) Inhibitive effects of fangchinoline at different concentrations on hydrolysis activity of 20S proteasome. Data were statistical results of three independent experiments.
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pone.0141681.g003: Inhibitive effects of fangchinoline on activity of purified human 20S proteasome.(A) Hydrolysis of the β1-specific fluorigenic peptide substrate Z-LLE-AMC at different concentrations by purified human 20S proteasome. (B) Time-dependent hydrolysis of 75 μM substrate Z-LLE-AMC by 20S proteasome with or without presence of 500 μM fangchinoline. (C) Inhibitive effects of fangchinoline at different concentrations on hydrolysis activity of 20S proteasome. Data were statistical results of three independent experiments.

Mentions: The hydrolysis curve of β1-specific fluorigenic peptide substrate Z-LLE-AMC at different concentrations by purified human 20S proteasome was shown in Fig 3A. The Km and Vmax of the purified proteasome was calculated to be 244.2 μM and 9.749X10-4 nmol/min, respectively. The representative time-dependent hydrolysis curves of Z-LLE-AMC (75 μM) by proteasome with or without presence of 500 μM fangchinoline were shown in Fig 3B. The results indicated that the hydrolysis of substrate by proteasome was partly inhibited in the presence of fangchinoline. The inhibitive effects of fangchinoline at different doses were shown in Fig 3C. The Ki of fangchinoline were calculated to be 356.58±30.63 μM.


Inhibition on Proteasome β1 Subunit Might Contribute to the Anti-Cancer Effects of Fangchinoline in Human Prostate Cancer Cells.

Li D, Lu Y, Sun P, Feng LX, Liu M, Hu LH, Wu WY, Jiang BH, Yang M, Qu XB, Guo DA, Liu X - PLoS ONE (2015)

Inhibitive effects of fangchinoline on activity of purified human 20S proteasome.(A) Hydrolysis of the β1-specific fluorigenic peptide substrate Z-LLE-AMC at different concentrations by purified human 20S proteasome. (B) Time-dependent hydrolysis of 75 μM substrate Z-LLE-AMC by 20S proteasome with or without presence of 500 μM fangchinoline. (C) Inhibitive effects of fangchinoline at different concentrations on hydrolysis activity of 20S proteasome. Data were statistical results of three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4626104&req=5

pone.0141681.g003: Inhibitive effects of fangchinoline on activity of purified human 20S proteasome.(A) Hydrolysis of the β1-specific fluorigenic peptide substrate Z-LLE-AMC at different concentrations by purified human 20S proteasome. (B) Time-dependent hydrolysis of 75 μM substrate Z-LLE-AMC by 20S proteasome with or without presence of 500 μM fangchinoline. (C) Inhibitive effects of fangchinoline at different concentrations on hydrolysis activity of 20S proteasome. Data were statistical results of three independent experiments.
Mentions: The hydrolysis curve of β1-specific fluorigenic peptide substrate Z-LLE-AMC at different concentrations by purified human 20S proteasome was shown in Fig 3A. The Km and Vmax of the purified proteasome was calculated to be 244.2 μM and 9.749X10-4 nmol/min, respectively. The representative time-dependent hydrolysis curves of Z-LLE-AMC (75 μM) by proteasome with or without presence of 500 μM fangchinoline were shown in Fig 3B. The results indicated that the hydrolysis of substrate by proteasome was partly inhibited in the presence of fangchinoline. The inhibitive effects of fangchinoline at different doses were shown in Fig 3C. The Ki of fangchinoline were calculated to be 356.58±30.63 μM.

Bottom Line: The inhibitive effect of fangchinoline on caspase-like activity of proteasome was also observed in purified human erythrocyte 20S proteasome.Treatment of PC-3 tumor-bearing nude mice with fangchinoline inhibited tumor growth, induced apoptosis and also caused decrease in proteasome activities in tumor xenografts.Results of the present study suggested that proteasome inhibition was involved in the anti-cancer effects of fangchinoline.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P.R. China; Changchun University of Chinese Medicine, Changchun 130117, P.R. China.

ABSTRACT
Fangchinoline is a bisbenzylisoquinoline alkaloid isolated from Radix Stephaniae tetrandrae S. Moore. Fangchinoline and its structure analogue, tetrandrine, exhibited direct binding affinity with recombinant human proteasome β1 subunit and also inhibited its activity in vitro. In cultured prostate PC-3 cells and LnCap cells, fangchinoline could dose-dependently inhibit cell proliferation and caspase-like activity of cellular proteasome which was mediated by proteasome β1 subunit. The inhibitive effect of fangchinoline on caspase-like activity of proteasome was also observed in purified human erythrocyte 20S proteasome. In PC-3 cells, fangchinoline induced cell cycle arrest at G0/G1 phase and apoptosis. Treatment of PC-3 tumor-bearing nude mice with fangchinoline inhibited tumor growth, induced apoptosis and also caused decrease in proteasome activities in tumor xenografts. Dose-dependent and time-dependent accumulation of ubiquitinated proteins and important proteasome substrates such as p27, Bax and IκB-α were observed in fangchinoline-treated cells. Over-expression of proteasome β1 subunit by plasmid transfection increased sensitivity of cells to the cytotoxicity of fangchinoline while knockdown of proteasome β1 subunit ameliorated cytotoxicity of fangchinoline in PC-3 cells. Results of the present study suggested that proteasome inhibition was involved in the anti-cancer effects of fangchinoline. Fangchinoline and its structure analogues might be new natural proteasome inhibitors targeting β1 subunit.

No MeSH data available.


Related in: MedlinePlus