In vitro toxicological characterisation of the antifungal compound soybean toxin (SBTX)

Area of Science:

• Biochemistry
• Molecular Biology
• Toxicology

Background:

• Soybean toxin (SBTX) is a protein from soybean seeds with demonstrated in vitro antifungal activity against various fungi and yeasts.
• The potential application of SBTX as a novel antifungal agent necessitates an evaluation of its safety profile on non-target organisms.

Purpose of the Study:

• To assess the in vitro safety of SBTX on non-target bacterial and mammalian cells.
• To investigate the effects of SBTX on gene expression in human intestinal cells.

Main Methods:

• Bacterial growth inhibition assays were performed using Salmonella enterica, Bacillus subtilis, and Staphylococcus aureus.
• Mammalian cell viability was assessed using erythrocytes, neutrophils, and Caco-2 cells.
• DNA microarray analysis was conducted on Caco-2 cells exposed to SBTX to evaluate gene expression alterations.

Main Results:

• SBTX at concentrations of 100 μg/mL and 200 μg/mL did not inhibit the growth of tested bacteria.
• SBTX up to 500 μg/mL showed no significant impact on the viability of erythrocytes, neutrophils, and Caco-2 cells.
• Microarray analysis revealed that SBTX up-regulated genes in cell cycle and immune response pathways, while down-regulating genes in cholesterol biosynthesis and platelet degranulation pathways.

Conclusions:

• SBTX exhibits antifungal activity without causing significant toxicity to non-target bacteria or mammalian cells in vitro.
• SBTX influences specific biological pathways in human Caco-2 cells, including cell cycle, immune response, cholesterol biosynthesis, and platelet degranulation.
• Further investigation is warranted to understand the implications of SBTX-induced gene expression changes in human cells.