Hypothesis-driven molecular design based on cruzain reversible covalent inhibitors

• Grant number: 14/06941-4
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: September 29, 2014
• End date: January 28, 2015
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Carlos Alberto Montanari
• Grantee: Carlos Alberto Montanari
• Visiting researcher: Peter W. Kenny
• Visiting researcher institution: Pessoa Física - Inglaterra, England
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 13/18009-4 - Molecular design, synthesis and trypanocidal activity of cruzain reversible covalent inhibitors, AP.TEM

Abstract

All the synthesised NEQUIMED compounds, supported by FAPESP Processes 2011/01893-3, 2011/20572-3 e 2008/04127-7, were active against cruzain in the range of low- to sub-micromolar concentrations. The most potent compound, Nequimed409 (Neq409), inhibited the enzyme with IC50 of 1.89 ± 0.11 µM (pIC50 = 5.7). These compounds showed trypanocidal activity against the trypomastigote/amastigote infective form Tulahuen lacZ strain at concentrations less than 50 µM. The prototype compound Neq409, potent against cruzain is also a trypanocidal agent (concentration-dependent response) with IC50 of 2.7 ± 0.3 µM (pIC50 = 5.6). Neq409 is more potent than the drug benznidazole (BZ), which was used as control (pIC50 = 4.6) and has minimal cytotoxicity in mice spleen (> 500 µM, comparable to BZ which is > 500 µM). The most promising dipeptidyl nitriles exhibit characteristics of leads that can be optimized for drug candidates: T. cruzi pIC50 > 5 (pIC50 (Neq409) = 5.6) with SI > 10 (SI ratio = IC50(cyto)/IC50(T. cruzi) = 185, BZ = 20.6); PFI < 8 (PFINeq409 = 3.7); # Ar rings < 5 and MW 500 < Da. Goals of this proposal: to optimize compounds for inhibiting cruzain in nanomolar concentrations. To study trypanocidal action of novel compounds with the goal of establishing a link between enzymatic and cellular activities. (AU)