MP20 'Omic' Technologies - Current and Future Applications to Environmental Toxicology
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(ZHA-1117-664803) A Comparison of H295R, R2C & JEG-3 cells as screening Tools for Effects on Steroidogenesis.

Zhang, X^{1, 2}, Yu, R², Jones, P¹, Newsted, J¹, Gracia, T, Hecker, M¹, Wu, R², Giesy, J^{1, 2}, ¹ Food Safety and Toxicology Center, Zoology Department, Michigan State University, East Lansing, MI, USA² Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong

ABSTRACT- Response profiles at the molecular level are promising for the evaluation of the toxic potential of environmental contaminants. Any alteration in the pathway of steroid synthesis and breakdown may cause endocrine disruption. In our previous studies (Zhang et al., EST 39(8), 2005), a method using the H295R (human adrenocortical carcinoma) cell line, was developed that simultaneously quantifies the expression of mRNA for 11 steroidogenic enzymes using Quantitative Real Time Polymerase Chain Reaction (Q-RT-PCR). In this study we further evaluated the rat Leydig cell carcinoma cell line R2C and human choriocarcinoma cell line JEG-3 and human adrenocorticocarcinoma cell line H295R for their suitability as in vitro screening tools for potential interference of xenobiotics with steroidogenesis. The basal mRNA expression of 11 steroidogenic enzymes in JEG-3 cells, R2C cells and H295R cells was quantified and compared using the previous method and newly developed RT-PCR primers for rat. Forskolin and trilostane, an inducer and an inhibitor of steroidogenesis, induced effect on steroidogenic enzymes for different periods (12h, 24h, and 48 h) in the three different cell lines were also quantified. The results indicate that all the cell lines express these key steroidogenic enzymes but H295R cells sustains more abundant mRNA level for most of the genes. Clustering analysis shows that three cell lines had similar gene expression profiles in response to the model chemicals. These analyses also showed that toxicant-specific gene expression patterns vary according to cell type. However H295R were the most sensitive cell line to the chemical induced effects. Overall H295R cells represent a more suitable in vitro tool to screen the effects of chemicals on steroidogenesis.

Key words: Endocrine Disruptors, Steroidogenesis, RT-PCR, Screening