PPAR-gamma ligand activation decreases p450 aromatase gene expression in human endometriotic epithelial and stromal cells in vitro

Abstract

OBJECTIVE: Endometriotic lesions express increased aromatase (CYP19, p450arom) levels, leading to local production of estrogen and, ultimately, persistence and self-propagation of these lesions. PPAR-gamma ligands have been shown to decrease p450arom in human granulosa cells and endometrial cells. We sought to determine if a PPAR-gamma ligand, ciglitazone (CIG), could affect aromatase expression in endometriotic epithelial and stromal cells.DESIGN: In vitro study using the immortalized human endometriotic epithelial cell line 12Z and stromal cell line 22B.MATERIALS AND METHODS: Endometriotic cells were cultured and subsequently treated with CIG x 24 hours. Treatment groups (n=3 for each experiment) consisted of control (no CIG compared to CIG at 20 μM). After RNA isolation and extraction, semiquantitative RT-PCR was performed to assess aromatase expression. Comparison of aromatase expression between treatment groups was made using a one-way ANOVA followed by post-hoc analysis.RESULTS: Our results indicated that activation of PPAR-gamma using CIG decreased expression of p450aromatase mRNA expression up to 90% in the endometriotic epithelial cells 12Z and up to 40% in the endometriotic stromal cells 22B.CONCLUSIONS: CIG treatment significantly decreased p450aromatase mRNA expression in a cell-specific manner in human endometriotic epithelial and stromal cells. Ongoing studies will unravel the underlying molecular and cellular interactions via in vivo animal models and human cells. If our subsequent in vivo animal and human studies show that PPAR-gamma activation facilitates regression of existing endometriotic lesions, thiazolidinediones such as pioglitazone may prove to be clinically useful for endometriosis-related pain and/or infertility. OBJECTIVE: Endometriotic lesions express increased aromatase (CYP19, p450arom) levels, leading to local production of estrogen and, ultimately, persistence and self-propagation of these lesions. PPAR-gamma ligands have been shown to decrease p450arom in human granulosa cells and endometrial cells. We sought to determine if a PPAR-gamma ligand, ciglitazone (CIG), could affect aromatase expression in endometriotic epithelial and stromal cells. DESIGN: In vitro study using the immortalized human endometriotic epithelial cell line 12Z and stromal cell line 22B. MATERIALS AND METHODS: Endometriotic cells were cultured and subsequently treated with CIG x 24 hours. Treatment groups (n=3 for each experiment) consisted of control (no CIG compared to CIG at 20 μM). After RNA isolation and extraction, semiquantitative RT-PCR was performed to assess aromatase expression. Comparison of aromatase expression between treatment groups was made using a one-way ANOVA followed by post-hoc analysis. RESULTS: Our results indicated that activation of PPAR-gamma using CIG decreased expression of p450aromatase mRNA expression up to 90% in the endometriotic epithelial cells 12Z and up to 40% in the endometriotic stromal cells 22B. CONCLUSIONS: CIG treatment significantly decreased p450aromatase mRNA expression in a cell-specific manner in human endometriotic epithelial and stromal cells. Ongoing studies will unravel the underlying molecular and cellular interactions via in vivo animal models and human cells. If our subsequent in vivo animal and human studies show that PPAR-gamma activation facilitates regression of existing endometriotic lesions, thiazolidinediones such as pioglitazone may prove to be clinically useful for endometriosis-related pain and/or infertility.