Artificial food sweetener aspartame induces stress response in model organism Schizosaccharomyces pombe

Abstract

Aspartame (APM) is a non-nutritive artificial sweetener that has been widely used in manyproducts since 1981. Molecular studies have found that it alters the expression of tumoursuppressor genes and oncogenes, forms DNA-DNA and DNA-protein crosslinks, and sisterchromatid exchanges. While these results confirm that aspartame is a carcinogenic substance,other studies have failed to detect any negative effect. The present work was aimed to revealthe molecular mechanisms of APM’s effects in the simpler model organism, Schizosaccharomycespombe, which has cellular processes similar to those of mammals. The human HP1(heterochromatin protein 1) family ortholog swi6 was selected for the evaluation because swi6expression is downregulated in cancer cells. Swi6 is a telomere, centromere, and mating-typelocus binding protein which regulates the structure of heterochromatin. To verify whether thecarcinogenic effects of APM are linked with Swi6, S. pombe parental and swi6Δ strains wereanalysed through a number of tests, including cell viability, intracellular oxidation, glucoseconsumption, nucleus DAPI (4',6-diamidino-2-phenylindole) staining, and quantitative realtime polymerase chain reaction (qRT-PCR) methods. Based on the results, the S. pombeparental strain adapts to APM effects by activating the stress response pathway, while swi6Δdid not show a meaningful response. Thus, it is proposed that there is a relationship betweenAPM and Swi6, and that APM may be carrying out its effects through Swi6. Nevertheless, itis understood that aspartame is not an effective carcinogenic agent since its effects are weakwhen compared with the swi6Δ phenotype.