D-verapamil and L-verapamil are equally effective in increasing vincristine accumulation in leukemic cells in vitro.
Leukemic cells isolated from peripheral blood from 6 patients with chronic lymphocytic leukemia, immunocytoma and prolymphocytic leukemia were incubated with vincristine (10 nM) with and without racemic verapamil and its L- and D-isomers (6.6 microM). Verapamil increased vincristine accumulation in all cells, the increase varying between 100 and 700%. Racemic verapamil and the L- and D-isomer increased cellular vincristine accumulation to the same extent. The verapamil effect could not be reversed by increasing the calcium concentration in the incubation medium (final concentration 2.5-5.0 mM). The results indicate that the mechanism behind the effect of verapamil on cellular accumulation of vincristine does not depend upon changes in calcium transport.
Gruber
A
A
Department of Medicine, Karolinska Hospital, Stockholm, Sweden.
Peterson
C
C
Reizenstein
P
P
D002118:Calcium / Q000378:metabolism; D004351:Drug Resistance; D006801:Humans; D007938:Leukemia / Q000378:metabolism*; D007945:Leukemia, Lymphoid / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D008223:Lymphoma / Q000378:metabolism; D013237:Stereoisomerism; D014700:Verapamil / Q000494:pharmacology*; D014750:Vincristine / Q000378:metabolism*
D014750:Vincristine; D014700:Verapamil; D002118:Calcium