Identification of a Proteasome-Targeting Arylsulfonamide with Potential for the Treatment of Chagas’ Disease

Abstract

Phenotypic screening identified an arylsulfonamide compound with activity against Trypanosoma cruzi , the causative agent of Chagas’ disease. Comprehensive mode of action studies revealed that this compound primarily targets the T. cruzi proteasome, binding at the interface between β4 and β5 subunits that catalyse chymotrypsin-like activity. A mutation in the β5 subunit of the proteasome was associated with resistance to compound 1 , while overexpression of this mutated subunit also reduced susceptibility to compound 1 . Further genetically engineered and in vitro selected clones resistant to proteasome inhibitors known to bind at the β4/β5 interface were cross-resistant to compound 1 . Ubiquitinylated proteins were additionally found to accumulate in compound 1 -treated epimastigotes. Finally, thermal proteome profiling identified malic enzyme as a secondary target of compound 1 , although malic enzyme inhibition was not found to drive potency. These studies identify a novel pharmacophore capable of inhibiting the T. cruzi proteasome that may be exploitable for anti-chagasic drug discovery.

State-of-the-Art in the Drug Discovery Pathway for Chagas Disease: A Framework for Drug Development and Target Validation

“…A similar approach was used to confirm the role of CPSF3, a protein involved in messenger RNA processing, as the target of AN15368, a new benzoxaborole analog with anti-parasitic activity and apparent low toxicity, and to identify its nature as a prodrug metabolized by a parasite serine carbopeptidase. 82 The same method was used to identify the β4/β5 interface in the parasite’s proteasome as the target of a new arylsulfonamide previously shown to present in vitro anti-parasitic activity, 37 , 104 confirming results from previous studies that suggested that inhibition of proteasome activity is an exploitable pathway in the treatment of kinetoplastid infections. 105 , 106 At least five compounds targeting CPSF3 or the kinetoplastid proteasome are currently in development pipelines for the identification of new treatments against kinetoplastid parasites, and three of these are potentially useful in the treatment of Chagas disease (see corresponding section below).…”

Anti-trypanosomatid drug discovery: progress and challenges

“…Quantitative measures of drug resistance can also be important in determining whether specific mutations are likely to have a detrimental impact in a clinical setting. Cas9-based editing has been applied to T. brucei CPSF3, providing insights into selective anti-trypanosomal action 52 , and to the Trypanosoma cruzi proteasome, revealing cross-resistance between arylsufonamides and distinct anti-leishmanials 130 . Oligonucleotide targeting, which is Cas9 independent, has also now been used to edit priority drug targets in trypanosomatids 131 .…”

Collaborative Virtual Screening Identifies a 2-Aryl-4-aminoquinazoline Series with Efficacy in an In Vivo Model of Trypanosoma cruzi Infection

“…The title compound (330 mg, 70.8%) was synthesized from 29b according to method F as a white solid. 1 (39). The title compound (1.20 g, 80%) was synthesized from 4,6-dichloro-1H-pyrazolo [3,4-d]pyrimidine (38) according to method F as a crude product.…”

“…Despite many interesting and fruitful approaches to identify new chemical entities for the treatment of T. cruzi infection in the past decade, − further research is still required to address CD, with the clear goal of obtaining an effective, orally bioavailable, affordable, and safe molecule effective in both the acute and chronic phases of the disease.…”