Diethylstilbestrol (DES), an estrogen agonist, increases prolactin (PRL) cells through transdifferentiation of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) cells to PRL cells as well as proliferation of PRL cells in adult male mouse pituitary. Since hyperacetylation of histone H3 is implicated in the regulation of activation of various genes, we examined the effect of DES on the state of histone H3 acetylation. DES significantly reduced the immunohistochemical signal for acetylated histone H3 at lysine 9 (H3K9ac) in PRL, LH and FSH cells, but not for H3K18ac or H3K23ac. DES-treated mice were injected intraperitoneally with HDAC inhibitors (HDACi), sodium phenylbutyrate (NaPB) or valproic acid (VPA), to mimic the acetylation level of histone H3. As expected, HDACi treatment restored the level of H3K9ac expression in these cells, and also inhibited DES-induced increase in PRL cells. Furthermore, NaPB and VPA also abrogated the effects of DES on the population density of both LH and FSH cells. Similarly, the numbers of proliferating and apoptotic cells in the pituitary in NaPB-or VPA-treated mice were comparable to those of the control mice. Considered together, these results indicated that the acetylation level of histone H3 plays an important role in DES-induced transdifferentiation of LH to PRL cells as well as proliferation of PRL cells.

B-cell lymphoma 9 (Bcl9) is the core component of Wnt/β-catenin signaling and overexpressed in nuclei of various tumors, including hepatocellular carcinoma (HCC). However, the extent of Bcl9 expression relative to HCC differentiation stage and its functional aspects are poorly understood. In this study, we examined the expression pattern of Bcl9 immunohistochemically, using two anti-Bcl9 antibodies; one was a conventional polyclonal-antibody (anti-Bcl9ABC) against amino acid no.800–900 of human-Bcl9, while the other (anti-Bcl9BIO) was against amino acid no.50–200, covering Pygopus-binding sites of Bcl9. Immunohistochemistry using anti-Bcl9BIO demonstrated distinctive staining in the cytoplasm, while the anti-Bcl9ABC signal was detected in both cytoplasm and nuclei of HCC cells, reflecting different states of Bcl9 function because Pygopus-binding to Bcl9 is essential to exert its function together with β-catenin in nucleus. Quantitative analysis revealed a significantly higher immunohistochemical-score by anti-Bcl9BIO in normal liver comparing various differentiation grades of HCC (P < 0.004), whereas no significant difference was noted with anti-Bcl9ABC. Interestingly, immunohistochemical-score of anti-Bcl9BIO in patients aged < 40 years was significantly lower than that of ≥ 40 years group (P < 0.01). The results indicated that anti-Bcl9BIO detected cytoplasmic Bcl9, which does not bind to Pygopus suggesting it could be a useful indicator for development of HCC in young Myanmar patients.