Effect of 3-Bromopyruvate and Atovaquone on Infection during In Vitro Interaction of Toxoplasma gondii and LLC-MK2 Cells

Abstract

bToxoplasma gondii infection can be severe during pregnancy and in immunocompromised patients. Current therapies for toxoplasmosis are restricted to tachyzoites and have little or no effect on bradyzoites, which are maintained in tissue cysts. Consequently, new therapeutic alternatives have been proposed as the use of atovaquone has demonstrated partial efficacy against tachyzoites and bradyzoites. This work studies the effect of 3-bromopyruvate (3-BrPA), a compound that is being tested against cancer cells, on the infection of LLC-MK2 cells with T. gondii tachyzoites, RH strain. No effect of 3-BrPA on host cell proliferation or viability was observed, but it inhibited the proliferation of T. gondii. The incubation of cultures with lectin Dolichos biflorus agglutinin (DBA) showed the development of cystogenesis, and an ultrastructural analysis of parasite intracellular development confirmed morphological characteristics commonly found in tissue cysts. Moreover, the presence of degraded parasites and the influence of 3-BrPA on endodyogeny were observed. Infected cultures were alternatively treated with a combination of this compound plus atovaquone. This resulted in a 73% reduction in intracellular parasites after 24 h of treatment and a 71% reduction after 48 h; cyst wall formation did not occur in these cultures. Therefore, we conclude that the use of 3-BrPA may serve as an important tool for the study of (i) in vitro cystogenesis; (ii) parasite metabolism, requiring a deeper understanding of the target of action of this compound on T. gondii; (iii) the alternative parasite metabolic pathways; and (iv) the molecular/cellular mechanisms that trigger parasite death.T oxoplasma gondii is an obligatory intracellular protozoan causative agent of toxoplasmosis that has a life cycle involving members of the family Felidae as definitive hosts and warmblooded animals, including humans, as intermediate hosts (1). The development of toxoplasmosis involves asexual replication. This gives rise to tachyzoites that are characterized by rapid growth during acute infection and bradyzoites found within tissue cysts, which slowly multiply and are responsible for the chronic phase of toxoplasmosis (2). In humans, the disease is typically asymptomatic; however, it is severe in immunocompromised individuals and congenital cases. For control of the infection, the most widely used therapy has been a combination of pyrimethamine and sulfadiazine (3), but this combination is commonly associated with several limitations due to adverse reactions, hypersensitivity, and hematologic toxicity (4). Although this combination is the treatment of choice and is used as prophylaxis, some patients are intolerant to this scheme and require alternative therapies (5). Atovaquone, a hydroxyl-1,4-naphthoquinone with a broad spectrum of antiprotozoan activity, has been FDA approved for the treatment of toxoplasmosis. This compound has shown efficacy against tachyzoites in vitro and in vivo (6, 7) and has a synergistic effect with clindamycin in acute muri...

The HK2 Dependent “Warburg Effect” and Mitochondrial Oxidative Phosphorylation in Cancer: Targets for Effective Therapy with 3-Bromopyruvate

“…Moreover, in vitro studies showed that 3BP could be successfully used in combination with atovaquone against Toxoplasma gondii . These studies also confirmed no effect of 3BP on host cell proliferation or viability [99].…”

In Vitro Activity of 3-Bromopyruvate, an Anticancer Compound, Against Antibiotic-Susceptible and Antibiotic-Resistant Helicobacter pylori Strains

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“…The cytotoxic activity against cancer cells is associated with the promotion of metabolic catastrophe, leading to interference with the activity of glycolytic enzymes and mitochondrial respiration proteins, the limitation of intracellular ATP and the induction of oxidative stress [15,16]. Additionally, antimicrobial activity of 3-BP directed against protozoa [20,21], fungi [22,23], microalgae [24], and bacteria [25,26] has also been demonstrated.…”

Synergistic Therapies as a Promising Option for the Treatment of Antibiotic-Resistant Helicobacter pylori

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