Epidermal growth factor–containing fibulin-like extracellular matrix protein 1 expression and regulation in uterine leiomyoma

ObjectiveTo determine the presence, differential expression, and regulation of epidermal growth factor–containing fibulin-like extracellular matrix protein 1 (EFEMP1) in uterine leiomyomas.DesignLaboratory in vivo and in vitro study with the use of human leiomyoma and myometrial tissue and primary cells.SettingAcademic medical center.Sample(s)Leiomyoma and myometrial tissue samples and cultured cells.Intervention(s)5-Aza-2′-deoxycytidine (5-aza-dC) treatment.Main Outcome Measure(s)Fold-change difference between EFEMP1 and fibulin-3 expression in leiomyoma tissue and cells compared with matched myometrial samples, and fold-change difference in EFEMP1 expression with 5-Aza-dC treatment.Result(s)In vivo, EFEMP1 expression was 3.19-fold higher in myometrial tissue than in leiomyoma tissue. EFEMP1 expression in vitro was 5.03-fold higher in myometrial cells than in leiomyoma cells. Western blot and immunohistochemistry staining of tissue and cells confirmed similar findings in protein expression. Treatment of leiomyoma cells with 5-Aza-dC resulted in increased expression of EFEMP1 in vitro.Conclusion(s)The EFEMP1 gene and its protein product, fibulin-3, are both significantly down-regulated in leiomyoma compared with myometrium when studied both in vivo and in vitro. The increase in EFEMP1 expression in leiomyoma cells with 5-Aza-dC treatment suggest that differential methylation is responsible, in part, for the differences seen in gene expression.