A Reagent-Free Screening Assay for Evaluation of the Effects of Chemicals on the Proliferation and Morphology of HeLa-GFP Cells

A reagent-free screening assay using HeLa cells with green fluorescent protein expressed in the cytoplasm was developed to describe adherence and proliferation of cells after seeding and to evaluate the dose- and time-dependent effects of three classes of chemicals, including metals (CdCl2, MeHg, HgCl2, and NiCl2), flame retardants [tris(1,3-dichloro-2-propyl) phosphate, heptadecafluoro-l-octanesulfonic acid, tetrabromobisphenol A, and tris(2-chloroethyl) phosphate], and phenolic fungicides (2,4,6-trichlorophenol, 4-tert-butylphenol, 3-bromo-phenol, and 2,4-dibromophenol), on the proliferation and morphology of cells. A seeding density of 5000 cells/well was determined to be optimal, and the most suitable duration of xenobiotic exposure was 120 h beginning 58 h postseeding. Dose- and time-dependent alterations in total fluorescence in the fluorescent field and number of cells, area per cell, and cellular roundness in the bright field were identified after exposure to each of the target chemicals. Results were comparable to those of the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay or other end points published in the literature for the same chemicals.