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

Objective To determine the presence, differential expression, and regulation of epidermal growth factor–containing fibulin-like extracellular matrix protein 1 (EFEMP1) in uterine leiomyomas. Design Laboratory in vivo and in vitro study with the use of human leiomyoma and myometrial tissue and primary cells. Setting Academic 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.