High-throughput screen identifies disulfiram as a potential therapeutic for triple-negative breast cancer cells: Interaction with IQ motif-containing factors

Abstract

Triple-negative breast cancer (TNBC) represents an aggressive subtype, for which radiation and chemotherapy are the only options. Here we describe the identification of disulfiram, an FDA-approved drug used to treat alcoholism, as well as the related compound thiram, as the most potent growth inhibitors following high-throughput screens of 3185 compounds against multiple TNBC cell lines. The average IC50 for disulfiram was ~300 nM. Drug affinity responsive target stability (DARTS) analysis identified IQ motif-containing factors IQGAP1 and MYH9 as direct binding targets of disulfiram. Indeed, knockdown of these factors reduced, though did not completely abolish, cell growth. Combination treatment with 4 different drugs commonly used to treat TNBC revealed that disulfiram synergizes most effectively with doxorubicin to inhibit cell growth of TNBC cells. Disulfiram and doxorubicin cooperated to induce cell death as well as cellular senescence, and targeted the ESA+/CD24-/low/CD44+ cancer stem cell population. Our results suggest that disulfiram may be repurposed to treat TNBC in combination with doxorubicin.

Drug Affinity Responsive Target Stability (DARTS) for Small-Molecule Target Identification

“…Mass spectrometry (MS) is then used to identify the proteins present in each band. This unbiased DARTS approach has been successfully utilized to identify novel protein targets for natural products and other bioactive small molecules; see (10) for a recent example identifying a novel protein target for disulfiram, an FDA-approved drug used to treat chronic alcoholism. Although this gel-based approach is the easiest to implement, more efficient gel-free proteomics approaches are also being used with DARTS to facilitate identification of the protected proteins (5, 11).…”

“…While DARTS has been successfully performed in an unbiased fashion as a discovery tool to identify unknown targets of natural products and drugs (see (9, 10, 12, 13) for some examples), it is also powerful as a means to screen or validate binding of compounds to proteins of interest. This targeted approach has been widely used, with recombinant and/or purified proteins using gel staining, endogenous proteins in lysates using western blotting, and epitope-tagged proteins expressed in cells or in vitro and detected with epitope-specific antibodies (9, 10, 14-19).…”

Disulfiram and Copper Ions Kill Mycobacterium tuberculosis in a Synergistic Manner

“…Studies to evaluate the potency of disulfiram against certain types of cancer (12)(13)(14), Menkes disease (15), and HIV-1 infections are ongoing or have just been completed (16,17). Of additional interest to the medical community are its antinematode (18), antifungal (19), and, importantly, its antibacterial properties (11,(20)(21)(22)(23)(24).…”

Existing drugs and their application in drug discovery targeting cancer stem cells

“…These candidate anticancer drugs are currently under clinical investigations for various types of cancer. Due to the growing demand for the existing drugs in anticancer drug discovery, a number of collections of existing drugs are now available commercially or noncommercially, which are amenable for high throughput screening (Chong et al 2006;Diamandis et al 2007;Doudican et al 2008;Huang et al 2011;Hothi et al 2012;Robinson et al 2013;Czyz et al 2014;Ketley et al 2014;Mei et al 2014) (Table 3).…”