INTERNATIONAL FOOD RESEARCH JOURNAL, vol.27, pp.208-216, 2020 (SCI-Expanded)
Aspartame (APM) is a non-nutritive artificial sweetener that has been widely used in many
products since 1981. Molecular studies have found that it alters the expression of tumour
suppressor genes and oncogenes, forms DNA-DNA and DNA-protein crosslinks, and sister
chromatid 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 reveal
the molecular mechanisms of APM’s effects in the simpler model organism, Schizosaccharomyces
pombe, which has cellular processes similar to those of mammals. The human HP1
(heterochromatin protein 1) family ortholog swi6 was selected for the evaluation because swi6
expression is downregulated in cancer cells. Swi6 is a telomere, centromere, and mating-type
locus binding protein which regulates the structure of heterochromatin. To verify whether the
carcinogenic effects of APM are linked with Swi6, S. pombe parental and swi6Δ strains were
analysed through a number of tests, including cell viability, intracellular oxidation, glucose
consumption, nucleus DAPI (4',6-diamidino-2-phenylindole) staining, and quantitative real
time polymerase chain reaction (qRT-PCR) methods. Based on the results, the S. pombe
parental strain adapts to APM effects by activating the stress response pathway, while swi6Δ
did not show a meaningful response. Thus, it is proposed that there is a relationship between
APM and Swi6, and that APM may be carrying out its effects through Swi6. Nevertheless, it
is understood that aspartame is not an effective carcinogenic agent since its effects are weak
when compared with the swi6Δ phenotype.