TY - JOUR
T1 - Effects of hyperthermia and cepharanthin on adriamycin accumulation with changes in extracellular ph
AU - Asaumi, J.
AU - Kawasaki, S.
AU - Nishikawa, K.
AU - Kuroda, M.
AU - Htraki, Y.
N1 - Funding Information:
'Thc present research was supported by Grants-in-Aid for Cancer Research from thc Ministry of Education, Science and Culture, Japan (nos. 01010023, 02151022 and 03 15 1022) and for Research on Priority areas (no. 602850225306).
PY - 1995
Y1 - 1995
N2 - We compared adriamycin (ADR) accumulation with the intensity of intracellular fluorescence of 3,3'-(di-n-hexyl)-2,2'-oxacarbocyanine iodide (NK-2280), an indicator of cell membrane potential, after hyperthermia and examined the effects of cepharanthin (CEP) on the accumulation of ADR and NK-2280 in wild and ADR-resistant strains of Ehrlich ascites tumour (EAT) cells. Among wild 0.2 and I-μg ADR-resistant strains of EAT cells, intracellular accumulation of both ADR and NK-2280 decreased with an increase of ADR resistance. Hyperthermia at 42°C and CEP induced a marked increase in accumulation of both ADR and NK-2280 in the ADR-resistant strains of EAT cells. The increase in ADR accumulation by hyperthermia and CEP is possibly due to an increase in the cell membrane potential and the inhibition of ADR efflux by CEP respectively. In the wild strain of EAT cells, we also evaluated the effect of extracellular pH change on ADR accumulation and the cell membrane potential and their alteration by hyperthermia and CEP. ADR accumulation decreased as pH decreased, but the cell membrane potential was not appreciably affected by pH change so far examined. Hyperthermia alone or combined with CEP significantly increased ADR accumulation in a pH range from 6.2 to 7.6. Hyperthermia increased the accumulation of ADR in the tumour cells, although its pH dependency was not completely resolved. CEP enhanced ADR accumulation more markedly in ADR-resistant cells than in wild-type cells. Therefore, the combination of hyperthermia and CEP may be very effective to increase the ADR cytotoxicity to ADR-resistant tumours.
AB - We compared adriamycin (ADR) accumulation with the intensity of intracellular fluorescence of 3,3'-(di-n-hexyl)-2,2'-oxacarbocyanine iodide (NK-2280), an indicator of cell membrane potential, after hyperthermia and examined the effects of cepharanthin (CEP) on the accumulation of ADR and NK-2280 in wild and ADR-resistant strains of Ehrlich ascites tumour (EAT) cells. Among wild 0.2 and I-μg ADR-resistant strains of EAT cells, intracellular accumulation of both ADR and NK-2280 decreased with an increase of ADR resistance. Hyperthermia at 42°C and CEP induced a marked increase in accumulation of both ADR and NK-2280 in the ADR-resistant strains of EAT cells. The increase in ADR accumulation by hyperthermia and CEP is possibly due to an increase in the cell membrane potential and the inhibition of ADR efflux by CEP respectively. In the wild strain of EAT cells, we also evaluated the effect of extracellular pH change on ADR accumulation and the cell membrane potential and their alteration by hyperthermia and CEP. ADR accumulation decreased as pH decreased, but the cell membrane potential was not appreciably affected by pH change so far examined. Hyperthermia alone or combined with CEP significantly increased ADR accumulation in a pH range from 6.2 to 7.6. Hyperthermia increased the accumulation of ADR in the tumour cells, although its pH dependency was not completely resolved. CEP enhanced ADR accumulation more markedly in ADR-resistant cells than in wild-type cells. Therefore, the combination of hyperthermia and CEP may be very effective to increase the ADR cytotoxicity to ADR-resistant tumours.
KW - Adriamycin
KW - Cell membrane potential
KW - Cepharanthin
KW - Extracellular pH
KW - Hyperthermia
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U2 - 10.3109/02656739509004945
DO - 10.3109/02656739509004945
M3 - Article
C2 - 7714368
AN - SCOPUS:0028919279
SN - 0265-6736
VL - 11
SP - 27
EP - 35
JO - International Journal of Hyperthermia
JF - International Journal of Hyperthermia
IS - 1
ER -
