Relationship between expression level of p-glycoprotein and daunorubicin transport in LLC-PK 1 cells transfected with human MDR1 gene

• Published in: Biochemical pharmacology Vol. 53; no. 5; pp. 741 - 746
• Main Authors: Tanaka, Kumiko, Hirai, Midori, Tanigawara, Yusuke, Ueda, Kazumitsu, Takano, Mikihisa, Hori, Ryohei, Ken-ichi, Inui
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1997
• Subjects: cyclosporin A; daunorubicin; multidrug resistance; P-glycoprotein; transcellular transport; P-glycoprotein; multidrug resistance; cyclosporin A; transcellular transport; daunorubicin
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(96)00810-6

P-Glycoprotein-mediated transcellular transport and intracellular accumulation of [ 3H]daunorubicin were examined in cell monolayers with different levels of P-glycoprotein. The porcine kidney epithelial cell line LLC-PK 1 was transfected with MDR1 cDNA, and four sublines, LLC-GA5, LLC-GA5-VLB4, LLC-GA5-COL10, and LLC-GA5-COL150, were obtained by culturing the cells in the absence or in the presence of 4 ng/mL vinblastine, 10 ng/mL colchicine, and 150 ng/mL colchicine, respectively. Western blot analysis showed a large difference in P-glycoprotein expression within these sublines. The degree of drug resistance was dependent on the expression level of P-glycoprotein. The amount of the unidirectional transport of [ 3H]daunorubicin by P-glycoprotein corresponded to the expression level of P-glycoprotein, which was followed by the decrease in intracellular accumulation of the agent. The concentration of cyclosporin A required for the inhibition of P-glycoprotein-mediated transport of [ 3H]daunorubicin was higher in cells with a high expression of P-glycoprotein. These findings suggest that the transport of daunorubicin by P-glycoprotein and its inhibition by cyclosporin A correspond to the expression level of P-glycoprotein.