Zosuquidar trihydrochloride

1. Alam A, Küng R, Kowal J, McLeod RA, Tremp N, Broude EV, Roninson IB, Stahlberg H, Locher KP.，Structure of a zosuquidar and UIC2-bound human-mouse chimeric ABCB1. Proc Natl Acad Sci U S A. 2018 Feb 27;115(9):E1973-E1982. doi: 10.1073/pnas.1717044115. Epub 2018 Feb 13.

2. Battistella C, Klok HA.，Reversion of P-gp-Mediated Drug Resistance in Ovarian Carcinoma Cells with PHPMA-Zosuquidar Conjugates. Biomacromolecules. 2017 Jun 12;18(6):1855-1865. doi: 10.1021/acs.biomac.7b00291. Epub 2017 May 4.

3. Abu Ajaj K1, Graeser R, Kratz F.，Zosuquidar and an albumin-binding prodrug of zosuquidar reverse multidrug resistance in breast cancer cells  and an albumin-binding prodrug. Breast Cancer Res Treat. 2012 Jul;134(1):117-29. doi: 10.1007/s10549-011-1937-9. Epub 2012 Jan 8.

4. Briglia M, Fazio A, Faggio C, Lang F.，Triggering of Suicidal Erythrocyte Death by Zosuquidar.

Cell Physiol Biochem. 2015;37(6):2355-65. doi: 10.1159/000438589. Epub 2015 Dec 7.

Abstract

BACKGROUND:

The P-glycoprotein inhibitor zosuquidar (LY335979) is clinically used to augment the effect of cytostatic drugs on suicidal tumor cell death or apoptosis. The present study explored whether the substance is cytotoxic to erythrocytes. Upon injury, erythrocytes may undergo suicidal cell death or eryptosis, which is characterized by cell shrinkage and translocation of cell membrane phosphatidylserine to the erythrocyte surface. Signaling of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i), oxidative stress and activation of several kinases, such as p38 kinase and protein kinase C.

METHODS:

Phosphatidylserine abundance at the erythrocyte surface was quantified from binding of FITC-labelled annexin-V, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, and reactive oxygen species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence.

RESULTS:

A 48 h treatment of human erythrocytes with zosuquidar significantly increased the percentage of annexin-V-binding cells (2 and 4 µg/ml), significantly decreased forward scatter (4 µg/ml), significantly increased [Ca2+]i (4 µg/ml), but did not significantly modify ROS. The up-regulation of annexin-V-binding following zosuquidar (4 µg/ml) treatment was significantly blunted by removal of extracellular Ca2+, by presence of p38 kinase inhibitor SB203580 (2 µM) and by presence of protein kinase C inhibitor calphostin (100 nM).

CONCLUSIONS:

Exposure of erythrocytes to zosuquidar triggers suicidal erythrocyte death with erythrocyte shrinkage and erythrocyte membrane scrambling, an effect involving Ca2+ entry and requiring activity of SB203580 and calphostin sensitive kinases.