High-Throughput Screening of the ReFRAME Library Identifies Potential Drug Repurposing Candidates for Trypanosoma cruzi

Abstract

Chagas disease, caused by the kinetoplastid parasite Trypanosoma cruzi, affects between 6 and 7 million people worldwide, with an estimated 300,000 to 1 million of these cases in the United States. In the chronic phase of infection, T. cruzi can cause severe gastrointestinal and cardiac disease, which can be fatal. Currently, only benznidazole is clinically approved by the FDA for pediatric use to treat this infection in the USA. Toxicity associated with this compound has driven the search for new anti-Chagas agents. Drug repurposing is a particularly attractive strategy for neglected diseases, as pharmacological parameters and toxicity are already known for these compounds, reducing costs and saving time in the drug development pipeline. Here, we screened 7680 compounds from the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) library, a collection of drugs or compounds with confirmed clinical safety, against T. cruzi. We identified seven compounds of interest with potent in vitro activity against the parasite with a therapeutic index of 10 or greater, including the previously unreported activity of the antiherpetic compound 348U87. These results provide the framework for further development of new T. cruzi leads that can potentially move quickly to the clinic.

Challenges in Chagas Disease Drug Development

“…Probably the most prominent recent development in Chagas disease drug research has been the increased use of high-throughput phenotypic screening [93][94][95]. The requirement for large compound libraries, robotic sample handling equipment, expertise in parasite biology, and over-arching funding mechanisms has brought together both the academic and commercial sectors, with not-for-profit drug development agencies, such as the DNDi.…”

Identification of Leucinostatins from Ophiocordyceps sp. as Antiparasitic Agents Against Trypanosoma cruzi

“…Primary screening of fungal extract samples. A subset of 5,631 samples from the University of Oklahoma fungal natural products library were tested at 2 µg/mL against T. cruzi strain CA-I/72 in a phenotypic high-content imaging assay we had previously developed and implemented in other drug discovery initiatives [16][17][18][19] . Dimethyl sulfoxide (DMSO) vehicle-treated infected mouse myocytes were included as positive infection controls, while infected mouse myocytes treated with 50 µM benznidazole were included as the negative infection control.…”

“…Treatment options for Chagas disease remain limited. Efforts to expand the scope of chemical scaffolds for drug discovery programs against T. cruzi using natural product, de novo design, and drug repositioning approaches have yielded promising new leads in recent years 9,16,[22][23][24][25] . Here, we used a high-throughput screening and bioactivity-guided fractionation pipeline to identify five potent leucinostatins from an Ophiocordyceps sp.…”

Repurposing the Kinase Inhibitor Mavelertinib for Giardiasis Therapy

“…Renewed interest in giardiasis therapeutic discovery has spiked due to advances in G. lamblia reporter systems that are ideal for whole-cell high-throughput screens and in vivo screening of pharmaceutical libraries ( 8 – 11 ). The ReFRAME library could accelerate the process of finding new treatments against giardiasis and other infectious parasitic diseases afflicting millions in countries that have limited drug discovery and development resources ( 14 – 17 ). With 37 compounds from pharmaceutical companies approved for various human clinical uses and >250 currently in clinical trials ( 31 ), finding kinase inhibitors that could be readily repurposed for treating giardiasis and other indications among this pool is highly desirable.…”