Identification of new Cruzipain inhibitory scaffolds from the GlaxoSmithKline HAT and CHAGAS chemical boxes

SARDUY ES; URAN LANDABURU L; CAZZULO JJ; AGÜERO F; ALVAREZ, V. E.

Santa Fe

Congreso; XXVIII Reunión Anual de la Sociedad Argentina de Protozoología y Enfermedades Parasitarias y SIMPOSIO Internacional de Biología Celular y Molecular de la Enfermedad de Chagas; 2016

Sociedad Argentina de Protozoología y Enfermedades Parasitarias (SAP)

American Trypanosomiasis or Chagas disease isa prevalent, neglected and potentially life-threatening illness caused by the kinetoplastidprotozoan parasite Trypanosoma cruzi. It isestimated that 8-11 million people are chronicallyinfected in Latin America, representing asubstantial social and economic burden. Owing tothe extensive global migration of asymptomatic,chronically infected individuals from endemicregions, Chagas disease now affects thousands ofpeople in nonendemic regions. The currentchemotherapy is limited only to nifurtimox andbenznidazole, two drugs that have limited efficacyin the chronic phase and are rather toxic. In thisscenario, more efficacious and safer drugs,preferentiallyactingthroughadifferentmechanism of action and directed against noveltargets, are particularly welcome. Cruzipain, themain papain-like cysteine peptidase of T. cruzi, isanimportantvirulencefactoranda chemotherapeutic target with excellent pre-clinicalvalidation evidence. The enzyme is involved in: i)parasite nutrition and differentiation, ii) invasion ofmammalian cells, iii) evasion of the host immuneresponse and iv) its inhibitors have proved toeffectively block parasite growth both ?in vitro? and?in vivo?. In this regard, the irreversible Cruzipaininhibitor K777 has been efficacious in preclinicalmodelsof T. cruziinfection, includingimmunocompetent and immunodeficient mice anddogs, confirming the potential of Cruzipaininhibitors as chemotherapeutic candidates for thetreatment of Chagas disease. Here, we presentthe identification of new Cruzipain inhibitoryscaffolds within the GlaxoSmithKline HAT andCHAGAS chemical boxes (two collectionsgrouping 404 non-cytotoxic compounds with highantiparasitic potency, drug-likeness, structuraldiversity and scientific novelty). To this end, weadapted a continuous enzymatic assay to a 384-multiwell format and carried out a primaryscreening of both compound collections, followedby construction and analysis of dose-responsecurves for the most promising hits. Using theidentified hits as starting point, structurally-relatedcompounds, not detected in the experimentalscreening or present only in the non-examinedLEISH chemical box, or in other public domainchemicaldatabaseswereidentifiedbycomputational methods. The potential bindingmode and mechanism of action of theseprototypic compounds will be discussed based onthis information.