Antineoplastic effects of dichloroacetate sodium and omeprazole in canine oral melanoma cell lines: a study of the mechanisms of action

Author(s)

Gabriela Fernandes de Toledo

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2023-03-14

Examining board members

Maria Lucia Zaidan Dagli; Carlos Eduardo Fonseca Alves; Simone Crestoni Fernandes; Bryan Eric Strauss

• Advisor: Maria Lucia Zaidan Dagli

Abstract

Sodium dichloroacetate (DCA) is a pyruvate dehydrogenase kinase (PDK) inhibitor, and omeprazole (OMP) is a proton pump inhibitor. In this work, we investigated the hypothesis that DCA and OMP have synergistic antineoplastic effects triggered by the metabolic modulation of the glycolytic pathway, and their mechanisms of action in canine oral melanoma (MOC) and human cutaneous melanoma cells. Therefore, the cell lines CMGD5 (canine oral melanoma) and SK-MEL-28 (human melanoma) were cultivated and treated with different concentrations of DCA and OMP individually or in association. An initial screening to determine cell viability after the use of the two drugs individually or in combination was performed using the crystal violet assay. Cell death by apoptosis or necrosis was studied by flow cytometry, using the fluorescent markers annexin V and propidium iodide. Bioenergetic analysis of cells treated or not with DCA and/or OMP was performed using the SeaHorseXF assay, evaluating the levels of oxygen consumption (OCR) of both strains after treatment with DCA and/or OMP. The use of the combination of the two drugs produced a significant reduction in the viability of the canine oral melanoma and human melanoma strains. The combination of DCA and OMP in the CMGD5 strain resulted in higher death rates by early apoptosis, while in the SK-MEL-28 strain the two predominant types of death were early apoptosis and necrosis. In the evaluation of OCR, DCA or OMP did not produce significant bioenergetic effects on CMGD5 and SK-MEL-28 cells; its effects were similar to those of untreated cells. In conclusion, as they present reduced cell viability and death by apoptosis, DCA and OMP can be considered reusage drugs for the treatment of melanoma. As for the mechanisms of action, DCA and OMP do not seem to interfere in a glycolytic metabolic perspective at the concentrations tested in CMGD5 and SK-MEL-28 cells. More studies are needed to determine the metabolic mechanisms leading to the antineoplastic effects of DCA and OMP in canine oral melanoma and human melanoma, and if they are eligible drugs to treat canines with oral melanoma (AU)

• FAPESP's process: 18/16515-3 - Antineoplastic effects of Dichloroacetate sodium (DCA) and omeprazole (OMP) in canine oral malignant melanoma cell lines: a study of the mechanisms of action
• Grantee: Gabriela Fernandes de Toledo
• Support Opportunities: Scholarships in Brazil - Master