Competitive interaction of cyclosporins with the Vinca alkaloid-binding site of P-glycoprotein in multidrug-resistant cells

Ikumi Tamai, Ahmad Safa

Research output: Contribution to journalArticle

160 Citations (Scopus)

Abstract

The mechanism of reversal of resistance to Vinca alkaloids by cyclosporins is unclear. We investigated the molecular mechanism of reversal of Vinca alkaloid resistance by cyclosporin A (CsA) and its nonimmunosuppressive analog O-acetyl C91 CsA (SDZ 33-243) in multidrug resistant DC-3F/VCRd-5L Chinese hamster cells. CsA at 3 μM increased vincristine (VCR) sensitivity and almost totally reversed VCR resistance. SDZ 33-243 at 1 μM reduced the IC50 for VCR in resistant cells from 62.0 to 0.00062 μM. CsA and SDZ 33-243 at 10 μM increased [3H]vinblastine (VBL) accumulation in DC-3F/VCRd-5L cells by 27- and 22-fold, respectively. At 10 μM, these compounds also increased [3H] VCR accumulation by 3.5- and 4.0-fold, respectively. [3H]VCR uptake by membrane vesicles from DC-3F/ VCRd-5L cells showed high and low affinity components with Michaelis-Menten kinetics, and apparent Km values were 0.140 ± 0.0523 and 24.8 ± 6.67 μM, respectively. Kinetic analysis of [3H]VCR uptake in membrane vesicles in the presence of 0.2 μM CsA revealed that CsA competitively inhibited the high affinity [3H]VCR uptake with an apparent inhibition constant (Ki) of 0.126 ± 0.0173 μM. In addition, CsA and SDZ 33-243 inhibited VBL photoaffinity labeling of P-glycoprotein in a dose-dependent manner, with half-maximum inhibition at 0.5 and 0.4 μM, respectively, compared with that of VBL at 0.6 μM. These data confirm that cyclosporins modulate Vinca alkaloid resistance at least partially through interaction with P-glycoprotein.

Original languageEnglish (US)
Pages (from-to)16509-16513
Number of pages5
JournalJournal of Biological Chemistry
Volume265
Issue number27
StatePublished - Sep 25 1990
Externally publishedYes

Fingerprint

Cyclosporins
Vinca Alkaloids
P-Glycoprotein
Vincristine
Cyclosporine
Binding Sites
Vinblastine
Membranes
Kinetics
Cricetulus
Labeling
Inhibitory Concentration 50
Cells

ASJC Scopus subject areas

  • Biochemistry

Cite this

Competitive interaction of cyclosporins with the Vinca alkaloid-binding site of P-glycoprotein in multidrug-resistant cells. / Tamai, Ikumi; Safa, Ahmad.

In: Journal of Biological Chemistry, Vol. 265, No. 27, 25.09.1990, p. 16509-16513.

Research output: Contribution to journalArticle

@article{da0fab854c7243e4b02680962996b770,
title = "Competitive interaction of cyclosporins with the Vinca alkaloid-binding site of P-glycoprotein in multidrug-resistant cells",
abstract = "The mechanism of reversal of resistance to Vinca alkaloids by cyclosporins is unclear. We investigated the molecular mechanism of reversal of Vinca alkaloid resistance by cyclosporin A (CsA) and its nonimmunosuppressive analog O-acetyl C91 CsA (SDZ 33-243) in multidrug resistant DC-3F/VCRd-5L Chinese hamster cells. CsA at 3 μM increased vincristine (VCR) sensitivity and almost totally reversed VCR resistance. SDZ 33-243 at 1 μM reduced the IC50 for VCR in resistant cells from 62.0 to 0.00062 μM. CsA and SDZ 33-243 at 10 μM increased [3H]vinblastine (VBL) accumulation in DC-3F/VCRd-5L cells by 27- and 22-fold, respectively. At 10 μM, these compounds also increased [3H] VCR accumulation by 3.5- and 4.0-fold, respectively. [3H]VCR uptake by membrane vesicles from DC-3F/ VCRd-5L cells showed high and low affinity components with Michaelis-Menten kinetics, and apparent Km values were 0.140 ± 0.0523 and 24.8 ± 6.67 μM, respectively. Kinetic analysis of [3H]VCR uptake in membrane vesicles in the presence of 0.2 μM CsA revealed that CsA competitively inhibited the high affinity [3H]VCR uptake with an apparent inhibition constant (Ki) of 0.126 ± 0.0173 μM. In addition, CsA and SDZ 33-243 inhibited VBL photoaffinity labeling of P-glycoprotein in a dose-dependent manner, with half-maximum inhibition at 0.5 and 0.4 μM, respectively, compared with that of VBL at 0.6 μM. These data confirm that cyclosporins modulate Vinca alkaloid resistance at least partially through interaction with P-glycoprotein.",
author = "Ikumi Tamai and Ahmad Safa",
year = "1990",
month = "9",
day = "25",
language = "English (US)",
volume = "265",
pages = "16509--16513",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "27",

}

TY - JOUR

T1 - Competitive interaction of cyclosporins with the Vinca alkaloid-binding site of P-glycoprotein in multidrug-resistant cells

AU - Tamai, Ikumi

AU - Safa, Ahmad

PY - 1990/9/25

Y1 - 1990/9/25

N2 - The mechanism of reversal of resistance to Vinca alkaloids by cyclosporins is unclear. We investigated the molecular mechanism of reversal of Vinca alkaloid resistance by cyclosporin A (CsA) and its nonimmunosuppressive analog O-acetyl C91 CsA (SDZ 33-243) in multidrug resistant DC-3F/VCRd-5L Chinese hamster cells. CsA at 3 μM increased vincristine (VCR) sensitivity and almost totally reversed VCR resistance. SDZ 33-243 at 1 μM reduced the IC50 for VCR in resistant cells from 62.0 to 0.00062 μM. CsA and SDZ 33-243 at 10 μM increased [3H]vinblastine (VBL) accumulation in DC-3F/VCRd-5L cells by 27- and 22-fold, respectively. At 10 μM, these compounds also increased [3H] VCR accumulation by 3.5- and 4.0-fold, respectively. [3H]VCR uptake by membrane vesicles from DC-3F/ VCRd-5L cells showed high and low affinity components with Michaelis-Menten kinetics, and apparent Km values were 0.140 ± 0.0523 and 24.8 ± 6.67 μM, respectively. Kinetic analysis of [3H]VCR uptake in membrane vesicles in the presence of 0.2 μM CsA revealed that CsA competitively inhibited the high affinity [3H]VCR uptake with an apparent inhibition constant (Ki) of 0.126 ± 0.0173 μM. In addition, CsA and SDZ 33-243 inhibited VBL photoaffinity labeling of P-glycoprotein in a dose-dependent manner, with half-maximum inhibition at 0.5 and 0.4 μM, respectively, compared with that of VBL at 0.6 μM. These data confirm that cyclosporins modulate Vinca alkaloid resistance at least partially through interaction with P-glycoprotein.

AB - The mechanism of reversal of resistance to Vinca alkaloids by cyclosporins is unclear. We investigated the molecular mechanism of reversal of Vinca alkaloid resistance by cyclosporin A (CsA) and its nonimmunosuppressive analog O-acetyl C91 CsA (SDZ 33-243) in multidrug resistant DC-3F/VCRd-5L Chinese hamster cells. CsA at 3 μM increased vincristine (VCR) sensitivity and almost totally reversed VCR resistance. SDZ 33-243 at 1 μM reduced the IC50 for VCR in resistant cells from 62.0 to 0.00062 μM. CsA and SDZ 33-243 at 10 μM increased [3H]vinblastine (VBL) accumulation in DC-3F/VCRd-5L cells by 27- and 22-fold, respectively. At 10 μM, these compounds also increased [3H] VCR accumulation by 3.5- and 4.0-fold, respectively. [3H]VCR uptake by membrane vesicles from DC-3F/ VCRd-5L cells showed high and low affinity components with Michaelis-Menten kinetics, and apparent Km values were 0.140 ± 0.0523 and 24.8 ± 6.67 μM, respectively. Kinetic analysis of [3H]VCR uptake in membrane vesicles in the presence of 0.2 μM CsA revealed that CsA competitively inhibited the high affinity [3H]VCR uptake with an apparent inhibition constant (Ki) of 0.126 ± 0.0173 μM. In addition, CsA and SDZ 33-243 inhibited VBL photoaffinity labeling of P-glycoprotein in a dose-dependent manner, with half-maximum inhibition at 0.5 and 0.4 μM, respectively, compared with that of VBL at 0.6 μM. These data confirm that cyclosporins modulate Vinca alkaloid resistance at least partially through interaction with P-glycoprotein.

UR - http://www.scopus.com/inward/record.url?scp=0025103799&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0025103799&partnerID=8YFLogxK

M3 - Article

C2 - 1975813

AN - SCOPUS:0025103799

VL - 265

SP - 16509

EP - 16513

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 27

ER -