A cell-based high-throughput screen identifies inhibitors that overcome P-glycoprotein (Pgp)-mediated multidrug resistance

Abstract

Multidrug resistance (MDR) to chemotherapeutic drugs remains one of the major impediments to the treatment of cancer. Discovery and development of drugs that can prevent and reverse the acquisition of multidrug resistance constitute a foremost challenge in cancer therapeutics. In this work, we screened a library of 1,127 compounds with known targets for their ability to overcome Pgp-mediated multidrug resistance in cancer cell lines. We identified four compounds (CHIR-124, Elesclomol, Tyrphostin-9 and Brefeldin A) that inhibited the growth of two pairs of parental and Pgp-overexpressing multidrug-resistant cell lines with similar potency irrespective of their Pgp status. Mechanistically, CHIR-124 (a potent inhibitor of Chk1 kinase) inhibited Pgp activity in both multidrug-resistant cell lines (KB-V1 and A2780-Pac-Res) as determined through cell-based Pgp-efflux assays. Other three inhibitors on the contrary, were effective in Pgp-overexpressing resistant cells without increasing the cellular accumulation of a Pgp substrate, indicating that they overcome resistance by avoiding efflux through Pgp. None of these compounds modulated the expression of Pgp in resistant cell lines. PIK-75, a PI3 Kinase inhibitor, was also determined to inhibit Pgp activity, despite being equally potent in only one of the two pairs of resistant and parental cell lines. Strong binding of both CHIR-124 and PIK-75 to Pgp was predicted through docking studies and both compounds inhibited Pgp in a biochemical assay. The inhibition of Pgp causes accumulation of these compounds in the cells where they can modulate the function of their target proteins and thereby inhibit cell proliferation. In conclusion, we have identified compounds with various cellular targets that overcome multidrug resistance in Pgp-overexpressing cell lines through mechanisms that include Pgp inhibition and efflux evasion. These compounds, therefore, can avoid challenges associated with the co-administration of Pgp inhibitors with chemotherapeutic or targeted drugs such as additive toxicities and differing pharmacokinetic properties.

Salvia miltiorrhiza in cancer: Potential role in regulating MicroRNAs and epigenetic enzymes

“…Moreover, tan IIA reduces the accumulation of β-catenin in the nucleus by repressing β-catenin nuclear translocation, which enhances Dox inhibition of MCF-7/Dox cell proliferation and migration ( Li et al, 2021 ). Adenosine triphosphate (ATP)-binding cassette (ABC) transporters, such as P-gp, breast cancer resistance protein (BCRP), and multidrug resistance-related protein 1 (MRP1), catalyze the transduction of structurally diverse compounds across cell membranes via ATP-dependent transport ( Zahra et al, 2020 ). Because ABC transporters are overexpressed in tumor cells, they pump out the chemotherapeutic drugs, thereby inducing tumor cells to acquire drug resistance ( Choi and Yu 2014 ).…”

Identification and Characterization of Natural and Semisynthetic Quinones as Aurora Kinase Inhibitors

“…All types of cells were passaged into new T75 flasks at 70% confluency. A sulforhodamine B (SRB) assay was performed to evaluate the antiproliferative activity of inhibitors, as described previously . Briefly, the cells were counted with a hemocytometer and seeded in 96-well plates at various cell concentrations specific to a particular cell line.…”

“…A sulforhodamine B (SRB) assay was performed to evaluate the antiproliferative activity of inhibitors, as described previously. 88 Briefly, the cells were counted with a hemocytometer and seeded in 96-well plates at various cell concentrations specific to a particular cell line. Following overnight incubation at 37 °C in a CO 2 -supplemented incubator, the cells were treated with nine 2-fold dilutions of inhibitors for 72 h. DMSO was used as a solvent control.…”

An organometallic analogue of combretastatin A-4 and its apoptosis-inducing effects on lymphoma, leukemia and other tumor cells in vitro

“…31,32 For this reason, we also tested NAHO27 against our resistant leukemia cell lines Nalm/BeKa and Nalm/LiKa, which are known to overexpress of P-glycoprotein (MDR1 transporter), a membrane-associated protein responsible for the active excretion of drugs from cancer cells to prevent them from binding their targets. 33,34 The fact that NAHO27 proved to be effective in inducing apoptosis also in these cells suggests an ability of this agent to overcome multiple drug resistance in cancer cells. Finally, we evaluated the use of NAHO27 (3) in a so-called combination therapy, which is a promising strategy to combat drug resistance in cancer treatment.…”