Evaluation of topotecan and 10-hydroxycamptothecin on Toxoplasma gondii: Implications on baseline DNA damage and repair efficiency

dc.contributor.authorCristaldi, Constanza
dc.contributor.authorSaldarriaga Cartagena, Ana M.
dc.contributor.authorGanuza, Agustina
dc.contributor.authorSullivan, William J., Jr.
dc.contributor.authorAngel, Sergio O.
dc.contributor.authorVanagas, Laura
dc.contributor.departmentPharmacology and Toxicology, School of Medicine
dc.date.accessioned2024-05-13T14:31:12Z
dc.date.available2024-05-13T14:31:12Z
dc.date.issued2023
dc.description.abstractToxoplasma gondii is an obligate intracellular parasite in the phylum Apicomplexa that causes toxoplasmosis in humans and animals worldwide. Despite its prevalence, there is currently no effective vaccine or treatment for chronic infection. Although there are therapies against the acute stage, prolonged use is toxic and poorly tolerated. This study aims to explore the potential of repurposing topotecan and 10-hydroxycamptothecin (HCPT) as drugs producing double strand breaks (DSBs) in T. gondii. DSBs are mainly repaired by Homologous Recombination Repair (HRR) and Non-Homologous End Joining (NHEJ). Two T. gondii strains, RHΔHXGPRT and RHΔKU80, were used to compare the drug's effects on parasites. RHΔHXGPRT parasites may use both HRR and NHEJ pathways but RHΔKU80 lacks the KU80 protein needed for NHEJ, leaving only the HRR pathway. Here we demonstrate that topotecan and HCPT, both topoisomerase I venoms, affected parasite replication in a concentration-dependent manner. Moreover, variations in fluorescence intensity measurements for the H2A.X phosphorylation mark (γH2A.X), an indicator of DNA damage, were observed in intracellular parasites under drug treatment conditions. Interestingly, intracellular replicative parasites without drug treatment show a strong positive staining for γH2A.X, suggesting inherent DNA damage. Extracellular (non-replicating) parasites did not exhibit γH2A.X staining, indicating that the basal level of DNA damage is likely to be associated with replicative stress. A high rate of DNA replication stress possibly prompted the evolution of an efficient repair machinery in the parasite, making it an attractive target. Our findings show that topoisomerase 1 venoms are effective antiparasitics blocking T. gondii replication.
dc.eprint.versionFinal published version
dc.identifier.citationCristaldi C, Saldarriaga Cartagena AM, Ganuza A, Sullivan WJ Jr, Angel SO, Vanagas L. Evaluation of topotecan and 10-hydroxycamptothecin on Toxoplasma gondii: Implications on baseline DNA damage and repair efficiency. Int J Parasitol Drugs Drug Resist. 2023;23:120-129. doi:10.1016/j.ijpddr.2023.11.004
dc.identifier.urihttps://hdl.handle.net/1805/40683
dc.language.isoen_US
dc.publisherElsevier
dc.relation.isversionof10.1016/j.ijpddr.2023.11.004
dc.relation.journalInternational Journal for Parasitology: Drugs and Drug Resistance
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.sourcePMC
dc.subjectToxoplasma gondii
dc.subjectTopotecan
dc.subject10-Hydroxycamptothecin
dc.subjectDNA damage
dc.subjectStress replication
dc.subjectDNA damage response
dc.titleEvaluation of topotecan and 10-hydroxycamptothecin on Toxoplasma gondii: Implications on baseline DNA damage and repair efficiency
dc.typeArticle
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