Accumulating evidence suggests that various epigenetic aberrations play definite roles in the pathogenesis of endometriosis.Objective:
The objective of the study was to determine the epigenetically silenced genes by histone deacetylation in endometriosis.Design:
Histone deacetylase-1 target mRNAs that were up-regulated by valproic acid (VPA) treatment in endometriotic cyst stromal cells (ECSCs) were identified by a global mRNA microarray technique.Results:
We identified 5 candidate genes and chose CCAAT/enhancer-binding protein α (C/EBPα) for further functional experiments. C/EBPα mRNA and protein expression is attenuated in ECSCs, and the expression was up-regulated by VPA stimulation. Immunohistochemical stainings also confirmed the decreased staining for C/EBPα protein in endometriotic tissues. VPA treatment resulted in an accumulation of acetylated histones H3 and H4 in the promoter region of the C/EBPα gene in ECSCs. The compulsory expression of C/EBPα in ECSCs directed the inhibition of cell proliferation and the induction of apoptosis. C/EBPα knockdown by small interfering RNA directed the stimulation of cell proliferation and the resistance to apoptosis in normal eutopic endometrial stromal cells. The expressions of peroxisome proliferator-activated receptor-γ (PPARγ), period homolog 2 (PER2), p53, apoptosis-inducing factor, mitochondrion-associated 1 (AIFM1), Bax, caspase-8, caspase-10, p16INK4a, p21Waf1/Cip1, cyclin-dependent kinase (cdk) 2, and cdk4 were down-regulated by C/EBPα knockdown.Conclusions:
Our findings suggest that an epigenetically suppressed tumor suppressor gene is involved in the pathogenesis of endometriosis by creating the proliferative, antiapoptotic, and other disease-specific characteristics of endometriosis. The results also suggest that histone deacetylase inhibitors are promising agents for the treatment of endometriosis.