Related Experiment Videos
Anthracyclines, proteasome activity and multi-drug-resistance
Mirela R Fekete1, William H McBride, Frank Pajonk
1Department of Neurology, Bürgerhospital, Tunzhofer Str. 14-16, 70191 Stuttgart, Germany. mirelafekete@gmx.de
BMC Cancer
|September 15, 2005
Summary
Anthracyclines, commonly used in chemotherapy, inhibit both the proteasome and P-glycoprotein. This dual action suggests potential therapeutic advantages in cancer treatment, particularly when combined with proteasome inhibitors for chemosensitization.
Area of Science:
- Biochemistry
- Molecular Biology
- Pharmacology
Background:
- P-glycoprotein (P-gp) mediates ATP-dependent drug efflux, contributing to multi-drug resistance and chemotherapy failure.
- Inhibitors of P-gp are sought to overcome treatment resistance.
- Previous observations indicated that certain substances inhibit both proteasome and P-gp.
Purpose of the Study:
- To investigate whether anthracyclines, known P-gp substrates, also inhibit proteasome function.
- To explore the potential dual inhibitory effects of chemotherapy drugs.
Main Methods:
- Assessed proteasome function in cell lysates using a fluorogenic peptide assay with various drugs.
- Monitored proteasome activity in living cells via stable transfection with ubiquitin/green fluorescent protein.
- Evaluated the effect of proteasome inhibitor MG-132 on P-glycoprotein function by measuring daunorubicin accumulation.
Main Results:
- Verapamil, daunorubicin, doxorubicin, idarubicin, and epirubicin dose-dependently inhibited 26S chymotrypsin-like proteasome activity.
- Most tested anthracyclines also suppressed 20S proteasome function.
- MG-132 blocked P-glycoprotein function, indicated by daunorubicin accumulation in P-gp overexpressing cells.
Conclusions:
- Anthracyclines exhibit dual inhibitory activity against both the 26S proteasome and P-glycoprotein.
- This dual action should be considered in cancer therapy, potentially for chemosensitization strategies using proteasome inhibitors.