Proteasomes, the proteolytic machinery of the ubiquitin/ATP-dependent pathway, have a relevant role in many processes crucial for cell physiology and cell cycle progression. Proteasome inhibitors are used to block cell cycle progression and to induce apoptosis in certain cell lines. Here we examine whether proteasomal function is affected by the anti-tumour drug vinblastine, whose cytostatic action relies mainly on the disruption of mitotic spindle dynamics. The effects of vinblastine on the peptidase activities of human 20S and 26S proteasomes and on the proteolytic activity of 26S proteasome were assessed in the presence of specific fluorogenic peptides and 125I-lysozyme–ubiquitin conjugates respectively. The assays of ubiquitin–protein conjugates and of inhibitory κBα (IκBα), which are characteristic intracellular proteasome substrates, by Western blotting on lysates from HL60 cells incubated with or without vinblastine, illustrated the effects of vinblastine on proteasomes in vivo. We also evaluated the effects of vinblastine on the signal-induced degradation of IκBα. Vinblastine at 3–110μM reversibly inhibited the chymotrypsin-like activity of the 20 S proteasome and the trypsin-like and peptidyl-glutamyl-peptide hydrolysing activities of both proteasomes, but only at 110μM vinblastine was the chymotrypsin-like activity of the 26S proteasome inhibited; furthermore, at 25–200μM the drug inhibited the degradation of ubiquitinated lysozyme. In HL60 cells exposed for 6h to 0.5–10μM vinblastine, the drug-dose-related accumulation of polyubiquitinated proteins, as well as that of a high-molecular-mass form of IκBα, occurred. Moreover, vinblastine impaired the signal-induced degradation of IκBα. Cell viability throughout the test was approx. 95%. Proteasomes can be considered to be a new and additional vinblastine target.
Skip Nav Destination
Article navigation
June 2001
- PDF Icon PDF LinkFront Matter
Research Article|
June 08 2001
Proteasomes are a target of the anti-tumour drug vinblastine
Marco PICCININI;
Marco PICCININI
∗Department of Experimental Medicine and Oncology, Section of Biochemistry, University of Turin, Via Michelangelo 27/B, 10126 Turin, Italy
Search for other works by this author on:
Ornella TAZARTES;
Ornella TAZARTES
∗Department of Experimental Medicine and Oncology, Section of Biochemistry, University of Turin, Via Michelangelo 27/B, 10126 Turin, Italy
Search for other works by this author on:
Caterina MEZZATESTA;
Caterina MEZZATESTA
†Department of Medical Sciences ‘A. Avogadro’, University of Eastern Piedmont, Via Solaroli 17, 28100 Novara, Italy
Search for other works by this author on:
Emanuela RICOTTI;
Emanuela RICOTTI
‡Department of Paediatric Sciences, University of Turin, Piazza Polonia 94, 10126 Turin, Italy
Search for other works by this author on:
Stefano BEDINO;
Stefano BEDINO
∗Department of Experimental Medicine and Oncology, Section of Biochemistry, University of Turin, Via Michelangelo 27/B, 10126 Turin, Italy
Search for other works by this author on:
Franca GROSSO;
Franca GROSSO
∗Department of Experimental Medicine and Oncology, Section of Biochemistry, University of Turin, Via Michelangelo 27/B, 10126 Turin, Italy
Search for other works by this author on:
Umberto DIANZANI;
Umberto DIANZANI
†Department of Medical Sciences ‘A. Avogadro’, University of Eastern Piedmont, Via Solaroli 17, 28100 Novara, Italy
Search for other works by this author on:
Pier-Angelo TOVO;
Pier-Angelo TOVO
‡Department of Paediatric Sciences, University of Turin, Piazza Polonia 94, 10126 Turin, Italy
Search for other works by this author on:
Michael MOSTERT;
Michael MOSTERT
‡Department of Paediatric Sciences, University of Turin, Piazza Polonia 94, 10126 Turin, Italy
Search for other works by this author on:
Alberto MUSSO;
Alberto MUSSO
‡Department of Paediatric Sciences, University of Turin, Piazza Polonia 94, 10126 Turin, Italy
Search for other works by this author on:
Maria T. RINAUDO
Maria T. RINAUDO
1
∗Department of Experimental Medicine and Oncology, Section of Biochemistry, University of Turin, Via Michelangelo 27/B, 10126 Turin, Italy
1To whom correspondence should be addressed (e-mail mariateresa.rinaudo@unito.it).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
October 16 2000
Revision Received:
February 27 2001
Accepted:
March 29 2001
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2001
2001
Biochem J (2001) 356 (3): 835–841.
Article history
Received:
October 16 2000
Revision Received:
February 27 2001
Accepted:
March 29 2001
Citation
Marco PICCININI, Ornella TAZARTES, Caterina MEZZATESTA, Emanuela RICOTTI, Stefano BEDINO, Franca GROSSO, Umberto DIANZANI, Pier-Angelo TOVO, Michael MOSTERT, Alberto MUSSO, Maria T. RINAUDO; Proteasomes are a target of the anti-tumour drug vinblastine. Biochem J 15 June 2001; 356 (3): 835–841. doi: https://doi.org/10.1042/bj3560835
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.