In vitro efficacy of bumped kinase inhibitors against Besnoitia besnoiti tachyzoites.

Jiménez-Meléndez, Alejandro; Ojo, Kayode K; Wallace, Alexandra M; Smith, Tess R; Hemphill, Andrew; Balmer, Vreni; Regidor-Cerrillo, Javier; Ortega-Mora, Luis M; Hehl, Adrian B; Fan, Erkang; Maly, Dustin J; Van Voorhis, Wesley C; Álvarez-García, Gema (2017). In vitro efficacy of bumped kinase inhibitors against Besnoitia besnoiti tachyzoites. International journal for parasitology, 47(12), pp. 811-821. Elsevier 10.1016/j.ijpara.2017.08.005

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Besnoitia besnoiti is an apicomplexan parasite responsible for bovine besnoitiosis, a chronic and debilitating disease that causes systemic and skin manifestations and sterility in bulls. Neither treatments nor vaccines are currently available. In the search for therapeutic candidates, calcium-dependent protein kinases have arisen as promising drug targets in other apicomplexans (e.g. Neospora caninum, Toxoplasma gondii, Plasmodium spp. and Eimeria spp.) and are effectively targeted by bumped kinase inhibitors. In this study, we identified and cloned the gene coding for BbCDPK1. The impact of a library of nine bumped kinase inhibitor analogues on the activity of recombinant BbCDPK1 was assessed by luciferase assay. Afterwards, those were further screened for efficacy against Besnoitiabesnoiti tachyzoites grown in Marc-145 cells. Primary tests at 5µM revealed that eight compounds exhibited more than 90% inhibition of invasion and proliferation. The compounds BKI 1294, 1517, 1553 and 1571 were further characterised, and EC(1294: 2.38µM; 1517: 2.20µM; 1553: 3.34µM; 1571: 2.78µM) were determined by quantitative real-time polymerase chain reaction in 3-day proliferation assays. Exposure of infected cultures with ECconcentrations of these drugs for up to 48h was not parasiticidal. The lack of parasiticidal action was confirmed by transmission electron microscopy, which showed that bumped kinase inhibitor treatment interfered with cell cycle regulation and non-disjunction of tachyzoites, resulting in the formation of large multi-nucleated complexes which co-existed with viable parasites within the parasitophorous vacuole. However, it is possible that, in the face of an active immune response, parasite clearance may occur. In summary, bumped kinase inhibitors may be effective drug candidates to control Besnoitiabesnoiti infection. Further in vivo experiments should be planned, as attainment and maintenance of therapeutic blood plasma levels in calves, without toxicity, has been demonstrated for BKIs 1294, 1517 and 1553.

Item Type:

Journal Article (Original Article)


05 Veterinary Medicine > Research Foci > Host-Pathogen Interaction
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Parasitology
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP)

UniBE Contributor:

Hemphill, Andrew and Balmer, Vreni


600 Technology > 630 Agriculture
500 Science > 540 Chemistry
500 Science > 570 Life sciences; biology








Andrew Hemphill

Date Deposited:

17 May 2018 17:07

Last Modified:

22 Oct 2019 18:52

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

Besnoitia besnoiti Bumped kinase inhibitors CDPK1 Chemotherapy In vitro assay




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