The role of DNA methylation and histone acetylation in the regulation of progesterone receptor isoforms expression in human astrocytoma cell lines

• Published in: Steroids Vol. 78; no. 5; pp. 500 - 507
• Main Authors: Hansberg-Pastor, Valeria, González-Arenas, Aliesha, Peña-Ortiz, Miguel A., García-Gómez, Elizabeth, Rodríguez-Dorantes, Mauricio, Camacho-Arroyo, Ignacio
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2013
• Subjects: 5-Aza-2′-deoxycytidine; Acetylation - drug effects; Astrocytoma - pathology; Astrocytomas; Azacitidine - analogs & derivatives; Azacitidine - pharmacology; Cell Line, Tumor; Cell Proliferation - drug effects; Cell Survival - drug effects; DNA methylation; DNA Methylation - drug effects; Gene Expression Regulation, Neoplastic - drug effects; Histone acetylation; Histones - metabolism; Humans; Hydroxamic Acids - pharmacology; Neoplasm Grading; Progesterone receptor isoforms; Protein Isoforms - genetics; Protein Isoforms - metabolism; Receptors, Progesterone - genetics; Receptors, Progesterone - metabolism; Trichostatin A; Progesterone receptor isoforms; PR; TSA; P4; DNA methylation; 5-Aza-2′-deoxycytidine; Histone acetylation; Trichostatin A; Astrocytomas; 5AzadC
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/j.steroids.2013.02.010

► DNA methylation reduces PR mRNA and protein expression in astrocytoma cell lines. ► PR-B expression is regulated by methylation in astrocytoma cells. ► Histone acetylation does not regulate PR-B expression in astrocytoma cell lines. ► DNA demethylation of astrocytoma cell lines reduces cell proliferation. Many progesterone (P4) effects are mediated by its intracellular receptor (PR), which has two isoforms, PR-A and PR-B, each of them with different function and regulation. Differential PR expression in cancer cells has been associated to a PR isoform-specific promoter methylation. In astrocytomas, the most frequent and aggressive brain tumors, PR isoforms expression is directly correlated to the tumor’s evolution grade. However, there is no evidence of the role of epigenetic regulation of PR expression in astrocytomas. We evaluated the effect of the demethylating agent 5-aza-2′-deoxycytidine (5AzadC) and the histone deacetylase inhibitor trichostatin A (TSA) on PR expression in human astrocytoma cell lines U373 (grade III) and D54 (grade IV) by RT-PCR and Western blot. Total PR expression increased with 5μM 5AzadC treatment, whereas PR-B expression increased with 5 and 10μM 5AzadC treatment in U373 cells, but not in D54 cells. In U373 cells, PR-A protein content augmented with 10μM 5AzadC treatment, while PR-B content increased with 5 and 10μM 5AzadC. PR-B expression was not modified by the TSA concentrations that were used, and the combination with 5AzadC did not change the effects of the latter. The study of 5AzadC effects on the number of astrocytoma cells showed that P4 treatment increased the number of U373 cells, whereas 5AzadC and the combined treatment with P4 reduced it. Our results suggest that PR-B expression is regulated by methylation and not by histone acetylation in U373 cells, and that DNA demethylation reduced the number of U373 cells.