Standardization of the 3-(4,5-Dimethylthiazol-2-yl)-5-(3-Carboxymethoxyphenyl)-2-(4-Sulfophenyl)-2H-Tetrazolium, Inner Salt (MTS) Assay for the SK-N-SH, KYSE-30, MCF-7, and HeLa Cell Lines

One common way to examine toxicity in vitro is to measure the effect on cell viability. In one such assay, the 3-4,5- dimethylthiazol-2-yl-5-3 -carboxymethoxyphenyl-2-4-sulfophenyl-2H-tetrazolium, inner salt MTS reagent is bioreduced to a formazan product in living cells. Various cell lines may have differing abilities to reduce MTS therefore, standardization should be carried out for each one. To optimize the assay, the toxicity of MTS, the linear range for signal versus cell number, and a method of background noise reduction were determined. The MTS reagent decreased cell number after 25 hr. The linear range for the neuronal SK-N-Sll, esophageal KYSE-30, breast MCF-7, and cervical HeLa cell lines were established. Finally, media containing no phenol red significantly reduced background noise compared to media with phenol red.