Transcriptomic effects of di-(2-ethylhexyl)-phthalate in Syrian hamster embryo cells: an important role of early cytoskeleton disturbances in carcinogenesis?

Abstract

BackgroundDi-(2-ethylhexyl)-phthalate (DEHP) is a commonly used plasticizer in polyvinylchloride (PVC) formulations and a potentially non-genotoxic carcinogen. The aim of this study was to identify genes whose level of expression is altered by DEHP by using a global wide-genome approach in Syrian hamster embryo (SHE) cells, a model similar to human cells regarding their responses to this type of carcinogen. With mRNA Differential Display (DD), we analysed the transcriptional regulation of SHE cells exposed to 0, 12.5, 25 and 50 μM of DEHP for 24 hrs, conditions which induced neoplastic transformation of these cells. A real-time quantitative polymerase chain reaction (qPCR) was used to confirm differential expression of genes identified by DD.ResultsGene expression profiling showed 178 differentially-expressed fragments corresponding to 122 genes after tblastx comparisons, 79 up-regulated and 43 down-regulated. The genes of interest were involved in many biological pathways, including signal transduction, regulation of the cytoskeleton, xenobiotic metabolism, apoptosis, lipidogenesis, protein conformation, transport and cell cycle. We then focused particularly on genes involved in the regulation of the cytoskeleton, one of the processes occurring during carcinogenesis and in the early steps of neoplastic transformation. Twenty one cytoskeleton-related genes were studied by qPCR. The down-regulated genes were involved in focal adhesion or cell junction. The up-regulated genes were involved in the regulation of the actin cytoskeleton and this would suggest a role of cellular plasticity in the mechanism of chemical carcinogenesis. The gene expression changes identified in the present study were PPAR-independent.ConclusionThis study identified a set of genes whose expression is altered by DEHP exposure in mammalian embryo cells. This is the first study that elucidates the genomic changes of DEHP involved in the organization of the cytoskeleton. The latter genes may be candidates as biomarkers predictive of early events in the multistep carcinogenic process.

Transcriptome profiling and pathway analysis of the effects of mono‑(2‑ethylhexyl) phthalate in mouse Sertoli cells

“…It was previously reported that MEHP is able to destroy the ES between rat Sertoli cells and spermatogenic cells, causing a release of the immature germ cells into the seminiferous tubule, which weakens reproductive function (35,36). The present study indicated that the expression of the genes that encode actinin and vinculin was decreased by MEHP, which was similar to the results of a previous study, in which Syrian hamster embryo cells were exposed to 50 µM DEHP for 24 h, revealing that the downregulated genes were associated with focal adhesion or cell junctions (37). This indicates that MEHP may affect the ECM-receptor interaction and focal adhesions to disrupt intercellular junctions and the formation of fissures between Sertoli cells and spermatogenic cells, resulting in the loss of spermatogenic cells from the seminiferous epithelium.…”

Integration of Epigenetic Mechanisms into Non-Genotoxic Carcinogenicity Hazard Assessment: Focus on DNA Methylation and Histone Modifications

“…SHE cell assay data further support links between one-carbon metabolism and cell transformation. SAH hydrolase is a tumor suppressor enzyme [81] reported to downregulate in di(2-ethylhexyl)phthalate (DEHP)-treated SHE cells [82]. Choline is known to be an important cellular metabolite and methyl donor in the one-carbon metabolism pathway, and diethanolamine reduces the uptake of choline to induce SHE cell morphological transformation [83].…”

Mechanistic Interrogation of Cell Transformation In Vitro: The Transformics Assay as an Exemplar of Oncotransformation

“…Due to the complexity of events that together contribute to chemical carcinogenesis, it is unlikely that a single method will be able to provide enough information about diverse events/mechanisms of actions and possible interactions [ 9 , 10 , 11 ]. Particularly, several studies have combined cellular transformation experiments using different cell lines with the transcriptome profiling, in order to explore the malignant transformation process [ 10 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”