High-Throughput Screening for Daunorubicin-Mediated Drug Resistance Identifies Mometasone Furoate as a Novel ABCB1-Reversal Agent

Abstract

The overexpression of P-glycoprotein, encoded by the ATP Binding Cassette B1 (ABCB1) gene, contributes to multidrug resistance (MDR) and is considered one of the major obstacles to successful cancer chemotherapy. The authors previously developed a T-lineage acute lymphoblastic leukemia (T-ALL) cell line that overexpresses ABCB1 and exhibits MDR to daunorubicin (DNR), prednisolone, and vincristine. Using this cell line and the fluorescent probe JC-1, they developed a flow cytometrybased, high-throughput screening (HTS) assay that quantifies ABCB1 efflux. They screened a library of 880 off-patent drugs for their ability to inhibit ABCB1 efflux and then measured the ability of 11 lead compounds to reverse in vitro DNR-mediated drug resistance and the toxic doses for each agent. Seven of the 11 drugs were able to reverse drug resistance at a concentration significantly below its toxic dose. Of the remaining 7, only 1 compound, mometasone furoate, has not been previously described as an ABCB1 antagonist to DNR-mediated drug resistance. On the basis of its high ABC modulator activity and relatively large in vitro therapeutic window, this drug warrants further investigation. In addition, the approach used in this study is useful for identifying off-patent drugs that may be repurposed for novel clinical indications. (Journal of Biomolecular Screening 2008:185-193)

A high throughput flow cytometric assay platform targeting transporter inhibition

“…We set out to develop new small molecule scaffolds with distinct efflux inhibition selectivity profiles based on multiplex transporter target screening. This approach paved the way for a series of innovations in chemical genetics including novel flow cytometry efflux assays in both mammalian (ABCB1, ABCB6, ABCG2, ABCC1) and yeast transporters including ABC (CDR1, CDR2 in Candida albicans , V-ATPase in Saccharomyces cerevisiae ) as well as MFS (MDR1 in C. albicans ) [38-41]. …”

Microbial Efflux Pump Inhibition: Tactics and Strategies

“…It paved the way for a series of innovations in chemical genetics including novel flow cytometry efflux assays (Fig. 4 and 5) in a set of yeast transporters including ABC (CDR1, CDR2), MFS (MDR1) and vacuolar V-ATPases [170–173]. Moreover this initiative has generated a number of projects targeting cancer MES including dye-substrate profiling and EPI discovery [170].…”

“…4 and 5) in a set of yeast transporters including ABC (CDR1, CDR2), MFS (MDR1) and vacuolar V-ATPases [170–173]. Moreover this initiative has generated a number of projects targeting cancer MES including dye-substrate profiling and EPI discovery [170]. UNMCMD has initiated a quest for ABC and MFS substrates and inhibitors both in microbial and mammalian systems.…”

Drug repurposing from an academic perspective

“…Led by Richard Larson, MD and Stuart Winter, MD (both UNMCC), a team of basic and clinical scientists at UNM have focused on the hypothesis that blocking multi-drug resistance protein 1 (MDR-1, also known as P-glycoprotein or ABCB1) could serve as adjuvant therapy in cancer, by enhancing the effectiveness of anti-cancer therapy. High-throughput flow cytometry screens conducted at UNMCMD identified mometasone furoate as one of the low-micromolar MDR-1 inhibitors [33] via flow-cytometric multiplex assays [34]. However, the dose required to achieve MDR-1 inhibition is almost 1000 times higher than the currently approved dose for allergic rhinitis.…”