ISSN:
1432-1335
Keywords:
Verapamil
;
B859-35
;
Multidrug resistance
;
P-170-glycoprotein
;
Adriamycin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary It has been shown previously that verapamil and other calcium antagonists and calmodulin inhibitors can reverse multidrug resistance. We compared the potency of the dihydropyridine derivatives (4R)-3-[3-(4,4-diphenyl-l-piperadinyl)-propyl]-5-methyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-pyridine-3,5-dicarboxylate-hydrochloride (B859-35), a metabolite of B859-35, niguldipine and (R)-nitrendipine to that of (RS)-verapamil in reversing multidrug resistance. The accumulation of the fluorescent dye rhodamine 123, which is transported by the P-glycoprotein, was determined by a flow cytometer. Multidrug-resistant human HeLa KB-8-5 and Walker rat carcinoma cells were incubated in the presence and in absence of the drugs indicated above. We found that 0.1 μM B859-35 increases the accumulation of rhodamine 123 in multidrug-resistant KB-8-5 and Walker cells more effectively than 1 μM (RS)-verapamil. In sensitive KB-3-1 cells addition of the drugs had no significant influence on the accumulation of rhodamine 123. In KB-8-5 cells, 10 nM Adriamycin caused a reduction of cell growth to 85% compared to untreated controls (=100%). If 1 μM B859-35, B859-35 metabolite, niguldipine, verapamil or (R)-nitrendipine was added to 10 nM Adriamycin, growth reduction compared with untreated controls increased to 12%, 11%, 23%, 63%, and 82% respectively. The effect of 0.1 μM B859-35 was a reduction in proliferation to 38%, that of 0.1 μM verapamil to 72%. These data illustrate that B859-35, a compound with antitumor activity in several tumors, is at least ten times more potent than racemic verapamil in reversing multidrug resistance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01294440
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