Effect of Mono-2-ethyhexyl Phthalate on DNA Methylation in Human Prostate Cancer LNCaP Cells.

OBJECTIVE: To evaluate whether mono (2-ethylhexyl) phthalate (MEHP) affects genomic DNA methylation and the methylation status of some specific genes such as patched gene (PTCH) and smoothened gene (SMO) in LNCaP cells.

METHODS: LNCaP cells were treated with MEHP (0, 1, 5, 10, and 25 μmol/L) for 3 days. An ELISA assay was preformed to detect genomic methylation, including 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) content. A pyrosequencing assay was applied to assess DNA methylation in PTCH and SMO gene promoters. The correlation between DNA methylation and gene expression was assessed.

RESULTS: The proportion of cytosines with 5-mC methylation in LNCaP cells was significantly decreased by MEHP (1, 5, 10, and 25 μmol/L) in a dose-dependent manner (P < 0.01). For genes in the Hedgehog pathway, there was no significant MEHP concentration-dependent difference in the DNA methylation of PTCH and SMO.

CONCLUSION: MEHP might affect the progression of prostate cancer through its effect on global DNA methylation.