Abstract
The effects of various flavonoids and carotenoids on Rhodamine 123 accumulation in multidrug-resistant Colo 320 human colon cancer cells expressing MDR1/LRP were studied. The Colo 205 cell line was used as a drug-sensitive control. Rotenon, Catechin, Neohesperidin, Naringin, Robinin, Phloridzin, Robinetin, Dihydrobinetin, Dihydrofisetin, Kampferol, Dihidroquercetin, Sakuranin and Sakuranetin were tested on Colo 320 cells: only Rotenon was found to be effective as regards multidrug resistance (MDR) reversal, while a majority of the flavonoids, such as Catechin, Neohesperidin, Naringin, Robinin, Phloridzin, Dihydrobinetin and Sakuranetin, had only marginal effects on Rhodamine 123 accumulation. The tested carotenoids (β-Cryptoxanthin, Luteoxanthin, Anteroxanthin, Violeoxanthin, Apple peel fetoxanthin, Lutein, Violaxanthin and Neoxanthin) were able to increase Rhodamine 123 accumulation in Colo 320 cells. Verapamil was applied as a resistance-modifying positive control. The levels of apoptosis induction in drug-resistant and - sensitive cell lines were also compared. The results indicated that the tested flavonoids were weak apoptosis inducers on MDR and parent cells, without significant differences. A majority of the carotenoids induced only early apoptosis, but apoptosis and cell death were not induced in MDR colon cancer cells.
Footnotes
- Received November 7, 2003.
- Revision received March 1, 2004.
- Accepted April 5, 2004.
- Copyright © 2005 The Author(s). Published by the International Institute of Anticancer Research.
