Utility of ToxTracker in animal alternative testing strategy for fragrance materials.

To determine the utility of the ToxTracker assay in animal alternative testing strategies, the genotoxic potential of four fragrance materials (2-octen-4-one, lauric aldehyde, veratraldehyde, and p-methoxy cinnamaldehyde) were tested in the ToxTracker assay. These materials have been previously evaluated in an in vitro as well as in vivo micronucleus assay, conducted as per OECD guidelines. In addition to these studies, reconstructed human skin micronucleus studies were conducted on all four materials.

Quantitative interpretation of ToxTracker dose-response data for potency comparisons and mode-of-action determination.

ToxTracker is an in vitro mammalian stem cell-based reporter assay that detects activation of specific cellular signaling pathways (DNA damage, oxidative stress, and/or protein damage) upon chemical exposure using flow cytometry. Here we used quantitative methods to empirically analyze historical control data, and dose-response data across a wide range of reference chemicals. First, we analyzed historical control data to define a fold-change threshold for identification of a significant positive response.

The surfactant co-formulant POEA in the glyphosate-based herbicide RangerPro but not glyphosate alone causes necrosis in Caco-2 and HepG2 human cell lines and ER stress in the ToxTracker assay.

The toxicity of co-formulants present in glyphosate-based herbicides (GBHs) has been widely discussed leading to the European Union banning the polyoxyethylene tallow amine (POEA). We identified the most commonly used POEA, known as POE-15 tallow amine (POE-15), in the widely used US GBH RangerPro. Cytotoxicity assays using human intestinal epithelial Caco-2 and hepatocyte HepG2 cell lines showed that RangerPro and POE-15 are far more cytotoxic than glyphosate alone.

Genotoxicity assessment of potentially mutagenic nucleoside analogues using ToxTracker®.

Nucleoside analogues have long been designed and tested in cancer treatment and against viral infections. However, several early compounds were shown to have mutagenic properties as a consequence of their mode-of-action. This limited their use, and several have been discontinued for lengthy treatments or altogether.

A novel human stem cell-based biomarker assay for in vitro assessment of developmental toxicity.

Background: Testing for developmental toxicity according to the current regulatory guidelines requires large numbers of animals, making these tests very resource intensive, time-consuming, and ethically debatable. Over the past decades, several alternative in vitro assays have been developed, but these often suffered from low predictability and the inability to provide a mechanistic understanding of developmental toxicity.

Methods: To identify embryotoxic compounds, we developed a human induced pluripotent stem cells (hiPSCs)-based biomarker assay.