Mechanism of transport and intracellular binding of porfiromycin in HCT 116 human colon carcinoma cells.
Cancer Res
; 49(18): 5048-53, 1989 Sep 15.
Article
em En
| MEDLINE
| ID: mdl-2766276
ABSTRACT
The mechanism of uptake and efflux of porfiromycin (PFM) by HCT 116 human colon carcinoma cells or freshly obtained human RBC was investigated. The time course of uptake of radioactivity upon exposure of HCT 116 cells to [14C]PFM showed one fast and one slow phase of linear increase. The initial phase of PFM uptake was not saturable with external drug concentrations from 2 to 100 microM. PFM accumulation was temperature dependent with a temperature coefficient (Q10 24-37 degrees C) of 2.3 +/- 0.3. PFM uptake was not affected either by individual inhibitors such as 1 mM 2,4-dinitrophenol, sodium azide, iodoacetic acid, ouabain, 0.02 mM oligomycin, p-hydroxylmercuribenzoate, 0.2 mM N-ethylmaleimide, or by combinations of inhibitors. PFM uptake did not demonstrate competitive inhibition by unlabeled PFM and mitomycin C. Efflux of cellular radioactivity was not affected by the above mentioned inhibitors or by verapamil, diltiazem, or trifluoperazine. Only aliphatic alcohols accelerated the initial influx rate. The RBC, however, only exhibited the initial fast accumulation of [14C]PFM, and all the 14C accumulated by RBC was exchangeable. These data demonstrate that the uptake and the efflux of PFM in HCT 116 cells and RBC comprise a passive diffusion process.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Porfiromicina
/
Células Tumorais Cultivadas
/
Mitomicinas
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
1989
Tipo de documento:
Article