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Bromocriptine reverses P-glycoprotein-mediated multidrug resistance in tumor cells
Nobuaki Shiraki1, Keiko Okamura, Jin Tokunaga
1Department of Pharmacy, Kumamoto University Hospital, Kumamoto 860-8556, Japan. ahamada@kaiju.medic.kumamoto-u.ac.jp
Japanese Journal of Cancer Research : Gann
|February 22, 2002
Summary
Bromocriptine effectively reverses multidrug resistance (MDR) in cancer cells by inhibiting P-glycoprotein (P-gp). This drug restores sensitivity to various anticancer agents, offering potential clinical applications for overcoming treatment failure.
Area of Science:
- Oncology
- Pharmacology
- Biochemistry
Background:
- Multidrug resistance (MDR) is a major cause of anticancer treatment failure.
- MDR is characterized by cross-resistance to various drugs and P-glycoprotein (P-gp) overexpression.
- P-gp is a transmembrane protein encoded by the MDR1 gene, responsible for drug efflux.
Purpose of the Study:
- To investigate the effect of bromocriptine on anticancer drug cytotoxicity and P-gp activity.
- To compare bromocriptine's influence in P-gp-expressing cells versus non-expressing cells.
Main Methods:
- Utilized a calcein-AM efflux assay to determine P-gp inhibition constants (K(i)).
- Assessed bromocriptine's impact on IC50 values of doxorubicin and vincristine in resistant cell lines.
- Evaluated bromocriptine's ability to restore sensitivity to multiple anticancer drugs.
Main Results:
- Bromocriptine demonstrated P-gp inhibitory activity with a K(i) of 6.52 microM.
- Bromocriptine significantly reduced IC50 values for doxorubicin and vincristine in MDR cells.
- Bromocriptine restored the efficacy of doxorubicin, vincristine, vinblastine, vinorelbine, and etoposide on MDR cells.
Conclusions:
- Bromocriptine effectively inhibits P-gp and reverses multidrug resistance in cancer cells.
- Bromocriptine has potential clinical applications for overcoming P-gp-mediated MDR.
- Further research is warranted to explore bromocriptine's role in cancer therapy.