Immunohistochemical Detection ofAcetylation and Phosphorylationof Histone H3 in Cervical Smears

Overview

Objective:
Histones bind in a sequence-independent manner to form chromatin. The aminoterminaltails of histones are targets for both phosphorylation and acetylation events. These modifi cationsare thought to fundamentally regulate chromatin structure to accommodate transcription,DNA replication, mitosis and DNA repair. Regeneration of squamous epithelium is accompaniedby marked cellular atypia, nuclear and nucleolar pleomorphism which could be confused withneoplasia. The aim of the study was to detect phosphorylated and acetylated forms of histone H3in cytological smears.Design: Translational research.Setting: Department of Experimental Oncology, Masaryk Memorial Cancer Institute, Departmentof Pathological Physiology, Medical Faculty and Department of Obstetrics and Gynecology, MasarykUniversity, Czech Republic.Methods: Smears from women aged between 20 to 46 years were selected. The specimens comprised10 squamous metaplasia, 20 CIN I, 12 CIN II, and 14 CIN III. The smears were stained withpolyclonal antibodies against phosphorylated and acetylated forms of histone H3.Results: We found that nuclear positivity for phosphorylated (P) and acetylated (A) forms of histoneH3 in CIN II (23% P, 33% A) and CIN III (25% P, 44% A) was higher in comparison with CIN I(8% P, 15% A) and metaplasia (11% P, 12% A).Conclusion: We revealed a marked association of histone H3 modifi cations with the progressionof CIN II, CIN III in comparison with CIN I and metaplasia. Our results are in agreement withrecent fi ndings: 1. staining of cells with anti-phospho-histone H3 antibodies therefore provides ahighly specifi c marker for mitosis. 2. acetylation of nucleosomal histones correlates with localisedtranscriptional activity.

Key words:
histone H3, acetylation, phosphorylation, cervical intraepithelial neoplasia