TY - JOUR
T1 - Modulation by d,l-buthionine-S,R-sulphoximine of etoposide cytotoxicity on human non-small cell lung, ovarian and breast carcinoma cell lines
AU - Mans, D. R A
AU - Schuurhuis, G. J.
AU - Treskes, M.
AU - Lafleur, M. V M
AU - Retèl, J.
AU - Pinedo, H. M.
AU - Lankelma, J.
PY - 1992
Y1 - 1992
N2 - Treatment with 25 μmol/l d,l-buthionine-S,R-sulphoximine (BSO) for at least 24 h depleted glutathione (GSH) in human non-small cell lung (SW-1573), ovarian (A2780) and breast carcinoma (MCF-7) cell lines to about 20% of control, and was accompanied by a 2-fold potentiation of the cytotoxicity of etoposide, doxorubicin and cisplatin. Cellular etoposide, but not doxorubicin or cisplatin, concentrations were increased 2-fold due to decreased efflux. This occurred independently of the presence of BSO during 1 h of etoposide exposure, but required prolonged exposure to BSO (at least 24 h). Energy depletion as well as cotreatment, but not pretreatment, of the cells with daunomycin, doxorubicin, vinblastine or vincristine increased cellular etoposide accumulation. Treatment of control cells with verapamil caused similar changes in etoposide cytotoxicity and cellular pharmacokinetics as GSH depletion, but did not further increase etoposide cytotoxicity and accumulation in GSH-depleted cells. Etoposide efflux may have been inhibited, not because of (competitive) inhibition by BSO or disturbance of the energy required for this process, but probably because of plasma membrane alterations.
AB - Treatment with 25 μmol/l d,l-buthionine-S,R-sulphoximine (BSO) for at least 24 h depleted glutathione (GSH) in human non-small cell lung (SW-1573), ovarian (A2780) and breast carcinoma (MCF-7) cell lines to about 20% of control, and was accompanied by a 2-fold potentiation of the cytotoxicity of etoposide, doxorubicin and cisplatin. Cellular etoposide, but not doxorubicin or cisplatin, concentrations were increased 2-fold due to decreased efflux. This occurred independently of the presence of BSO during 1 h of etoposide exposure, but required prolonged exposure to BSO (at least 24 h). Energy depletion as well as cotreatment, but not pretreatment, of the cells with daunomycin, doxorubicin, vinblastine or vincristine increased cellular etoposide accumulation. Treatment of control cells with verapamil caused similar changes in etoposide cytotoxicity and cellular pharmacokinetics as GSH depletion, but did not further increase etoposide cytotoxicity and accumulation in GSH-depleted cells. Etoposide efflux may have been inhibited, not because of (competitive) inhibition by BSO or disturbance of the energy required for this process, but probably because of plasma membrane alterations.
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U2 - 10.1016/0959-8049(92)90541-9
DO - 10.1016/0959-8049(92)90541-9
M3 - Article
C2 - 1325177
AN - SCOPUS:0026724218
SN - 0959-8049
VL - 28
SP - 1447
EP - 1452
JO - European Journal of Cancer
JF - European Journal of Cancer
IS - 8-9
ER -