Hematin Polymerization Assay as a High-Throughput Screen for Identification of New Antimalarial Pharmacophores

Kurosawa, Yae; Dorn, Arnulf; Kitsuji-Shirane, Michiko; Shimada, Hiraku; Satoh, Tomoko; Matile, Hugues; Hofheinz, W.; Masciadri, Raffaello; Kansy, Manfred; Ridley, Robert G.

doi:10.1128/aac.44.10.2638-2644.2000

Cited by 79 publications

(63 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…35 and data not shown). The interaction with heme might suggest that the modes of action of this class of compounds resemble those of other heme-interaction antimalarials (36)(37)(38). However, they have shown high efficacy against multiresistant P. falciparum field isolates and genetically modified P. falciparum clones expressing mutant forms of the CQ resistance determinant pfcrt (P. Ringwald and D. A. Fidock, unpublished work), and we have evidence of distinct action toward heme polymerization (H.J.V.…”

Section: Discussionmentioning

confidence: 99%

Prodrugs of bisthiazolium salts are orally potent antimalarials

Vial

Wein

Farenc

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

105

151

View full text Add to dashboard Cite

We created neutral antimalarial prodrugs that deliver bisthiazolium compounds with antimalarial activity in the nanomolar range. These drugs primarily affect early intraerythrocytic stages through rapid, nonreversible cytotoxicity. The compounds are suitable for both parenteral and oral use and plasma promotes rapid conversion of the prodrug into the drug. We demonstrate that very low doses offer protection in a murine model of malaria. The drugs show great potential for curing high parasitemia with short-course treatments. Oral administration of the TE3 prodrug completely cures Plasmodium cynomolgi infection in rhesus monkeys. The drugs specifically accumulate inside infected erythrocytes, block phosphatidylcholine biosynthesis, and interact with hemozoin. To our knowledge, this class of compounds represents one of the most potent antimalarials tested to date. These unique properties signal a promising future for this class of antimalarial.M alaria is a public health problem affecting Ͼ40% of the world's population. It causes up to 2 million deaths, mostly young children, in Africa, and Ͼ300 million clinical cases each year (1), with major consequent impact on economic productivity and livelihood (2). Currently, there are no licensed vaccines and the spread of drug-resistant parasites and insecticideresistant mosquitoes is an increasing problem. New antimalarial compounds, particularly those based on compounds structurally unrelated to existing antimalarial drugs with new mechanisms of action, are urgently needed (3-5).We have developed classes of antimalarial drugs targeting membrane biogenesis during intraerythrocytic Plasmodium falciparum development. We have focused on mono-and bisquaternary ammonium compounds for their potent antimalarial activity in vitro and in vivo (6, 7). These compounds mimic choline structure; they potently inhibit the low-affinity choline carrier related to phospholipid biosynthesis in eukaryotic cells and the high-affinity carrier involved in biosynthesis of the neurotransmitter acetylcholine in the CNS (8, 9). These compounds have exceptional in vitro and in vivo antimalarial properties devoid of mutagenic activity (10 -12).G25 [1,16-hexadecamethylenebis(N-methylpyrrolidinium) dibromide] and other drugs in this class possess a permanently charged cationic group (7, 13) that is essential for activity but detrimental to oral absorption. This action prejudiced development for the clinic. Oral administration is essential for treatment in dispensaries in endemic countries and for prophylactic or curative treatment for travelers. A targeting carrier system is unsuitable because, in the absence of carrier-mediated specific processes, quaternary ammonium compounds are intrinsically incapable of crossing bilayered cellular membranes. Designing drugs that mask the ionizable groups was therefore the most attractive solution. This was the rationale behind development of a chemically modified form of drug that is converted into an active ionized form by enzymes present in plasma. Here, we repo...

show abstract

Section: Discussionmentioning

confidence: 99%

Prodrugs of bisthiazolium salts are orally potent antimalarials

Vial

Wein

Farenc

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

105

151

View full text Add to dashboard Cite

show abstract

“…This screen to identify novel antimalarial chemotypes targeting heme crystallization yielded compounds unlike those described in a notable previous effort, a radioisotope screen conducted at Roche, and unlike those based on modifying the quinoline scaffold (13,14,16,23). Possibly as a result of being able to conduct an HTS on unbiased libraries, the compounds identified in this screen had comparable antimalarial efficacies in both the CQ-sensitive strain 3D7 and the CQ-resistant strain Dd2 of P. falciparum.…”

Section: Discussionmentioning

confidence: 99%

“…Micromolar compound concentrations have been used in all heme crystallization screens described to date, even when the in vivo activity of the compound is in the nanomolar range, and therefore the CFHCS is within the range published for heme crystallization assays (4,9,11,13,19). Many known heme crystallization inhibitors are weak bases, which have been shown to reach high local concentrations through accumulation in the acidic food vacuole through a pH-trapping mechanism (27).…”

Section: Discussionmentioning

confidence: 99%

Colorimetric High-Throughput Screen for Detection of Heme Crystallization Inhibitors

Rush

Baniecki

Mazitschek

et al. 2009

Antimicrob Agents Chemother

View full text Add to dashboard Cite

Malaria infects 500 million people annually, a number that is likely to rise as drug resistance to currently used antimalarials increases. During its intraerythrocytic stage, the causative parasite, Plasmodium falciparum, metabolizes hemoglobin and releases toxic heme, which is neutralized by a parasite-specific crystallization mechanism to form hemozoin. Evidence suggests that chloroquine, the most successful antimalarial agent in history, acts by disrupting the formation of hemozoin. Here we describe the development of a 384-well microtiter plate screen to detect small molecules that can also disrupt heme crystallization. This assay, which is based on a colorimetric assay developed by Ncokazi and Egan (K. K. Ncokazi and T. J. Egan, Anal. Biochem. 338:306-319, 2005), requires no parasites or parasite-derived reagents and no radioactive materials and is suitable for a high-throughput screening platform. The assay's reproducibility and large dynamic range are reflected by a Z factor of 0.74. A pilot screen of 16,000 small molecules belonging to diverse structural classes was conducted. The results of the target-based assay were compared with a whole-parasite viability assay of the same small molecules to identify small molecules active in both assays.

show abstract

“…The detergent NP-40 served as a mediator for ␤-hematin formation due to its stability, low cost, and low IC 50 , beside its similarity to the natural lipid particles of the parasite's vacuole (21,43). Dimethyl sulfoxide (DMSO), from Wako Pure Chemicals, Osaka, Japan, was chosen as the negative control because of its proven inability to inhibit the heme crystallization reaction (44).…”

Section: Methodsmentioning

confidence: 99%

High-Throughput Screening and Prediction Model Building for Novel Hemozoin Inhibitors Using Physicochemical Properties

Huy

Lan

Nagai

et al. 2017

Antimicrob Agents Chemother

View full text Add to dashboard Cite

It is essential to continue the search for novel antimalarial drugs due to the current spread of resistance against artemisinin by Plasmodium falciparum parasites. In this study, we developed in silico models to predict hemozoin inhibitors as a potential first-step screening for novel antimalarials. An in vitro colorimetric highthroughput screening assay of hemozoin formation was used to identify hemozoin inhibitors from 9,600 structurally diverse compounds. The physicochemical properties of positive hits and randomly selected compounds were extracted from the ChemSpider database; they were used for developing prediction models to predict hemozoin inhibitors using two different approaches, i.e., traditional multivariate logistic regression and Bayesian model averaging. Our results showed that a total of 224 positive-hit compounds exhibited the ability to inhibit hemozoin formation, with 50% inhibitory concentrations (IC 50 s) ranging from 3.1 M to 199.5 M. The best model according to traditional multivariate logistic regression included the three variables octanol-water partition coefficient, number of hydrogen bond donors, and number of atoms of hydrogen, while the best model according to Bayesian model averaging included the three variables octanol-water partition coefficient, number of hydrogen bond donors, and index of refraction. Both models had a good discriminatory power, with area under the curve values of 0.736 and 0.781 for the traditional multivariate model and Bayesian model averaging, respectively. In conclusion, the prediction models can be a new, useful, and cost-effective approach for the first screen of hemozoin inhibition-based antimalarial drug discovery.

show abstract

Hematin Polymerization Assay as a High-Throughput Screen for Identification of New Antimalarial Pharmacophores

Cited by 79 publications

References 25 publications

Prodrugs of bisthiazolium salts are orally potent antimalarials

Prodrugs of bisthiazolium salts are orally potent antimalarials

Colorimetric High-Throughput Screen for Detection of Heme Crystallization Inhibitors

High-Throughput Screening and Prediction Model Building for Novel Hemozoin Inhibitors Using Physicochemical Properties

Contact Info

Product

Resources

About