Potent Trypanocidal curcumin analogs bearing a monoenone linker motif act on Trypanosoma brucei by forming an adduct with Trypanothione

Alkhaldi, A.A.M., Creek, D.J., Ibrahim, H., Kim, D.-H., Quashie, N.B., Burgess, K.E., Changtam, C., Barrett, M.P. , Suksamrarn, A. and De Koning, H.P. (2015) Potent Trypanocidal curcumin analogs bearing a monoenone linker motif act on Trypanosoma brucei by forming an adduct with Trypanothione. Molecular Pharmacology, 87(3), pp. 451-464. (doi:10.1124/mol.114.096016) (PMID:25527638)

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Abstract

We have previously reported that curcumin analogs with a C7 linker bearing a C4-C5 olefinic linker with a single keto group at C3 (enone linker) display midnanomolar activity against the bloodstream form of Trypanosoma brucei. However, no clear indication of their mechanism of action or superior antiparasitic activity relative to analogs with the original di-ketone curcumin linker was apparent. To further investigate their utility as antiparasitic agents, we compare the cellular effects of curcumin and the enone linker lead compound 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (AS-HK014) here. An AS-HK014–resitant line, trypanosomes adapted to AS-HK014 (TA014), was developed by in vitro exposure to the drug. Metabolomic analysis revealed that exposure to AS-HK014, but not curcumin, rapidly depleted glutathione and trypanothione in the wild-type line, although almost all other metabolites were unchanged relative to control. In TA014 cells, thiol levels were similar to untreated wild-type cells and not significantly depleted by AS-HK014. Adducts of AS-HK014 with both glutathione and trypanothione were identified in AS-HK014–exposed wild-type cells and reproduced by chemical reaction. However, adduct accumulation in sensitive cells was much lower than in resistant cells. TA014 cells did not exhibit any changes in sequence or protein levels of glutathione synthetase and γ-glutamylcysteine synthetase relative to wild-type cells. We conclude that monoenone curcuminoids have a different mode of action than curcumin, rapidly and specifically depleting thiol levels in trypanosomes by forming an adduct. This adduct may ultimately be responsible for the highly potent trypanocidal and antiparasitic activity of the monoenone curcuminoids.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Quashie, Mr Neils and De Koning, Professor Harry and Creek, Dr Darren and Burgess, Dr Karl and Barrett, Professor Michael
Authors: Alkhaldi, A.A.M., Creek, D.J., Ibrahim, H., Kim, D.-H., Quashie, N.B., Burgess, K.E., Changtam, C., Barrett, M.P., Suksamrarn, A., and De Koning, H.P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Molecular Pharmacology
Publisher:American Society for Pharmacology and Experimental Therapeutics
ISSN:1521-0111
ISSN (Online):1521-0111

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
371796The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/Z/08/ZIII - PARASITOLOGY