Because the p300/CBP-mediated hyperacetylation of RelA (p65) is critical for nuclear factor-KB (NF-KB) activation, the attenuation of p65 acetylation is a potential molecular target for the prevention of chronic inflammation. During our ongoing screening study to identify natural compounds with histone acetyltransferase inhibitor (HATi) activity, we identified epigallocatechin-3-gallate (EGCG) as a novel HATi with global specificity for the majority of HAT enzymes but with no activity toward epigenetic enzymes including HDAC, SIRT1, and HMTase. At a dose of 100 Mmol/L, EGCG abrogates p300-induced p65 acetylation in vitro and in vivo, increases the level of cytosolic IKBA, and suppresses tumor necrosis factor A (TNFA)-induced NF-KB activation. We also showed that EGCG prevents TNFA-induced p65 translocation to the nucleus, confirming that hyperacetylation is critical for NF-KB translocation as well as activity. Furthermore, EGCG treatment inhibited the acetylation of p65 and the expression of NF-KB target genes in response to diverse stimuli. Finally, EGCG reduced the binding of p300 to the promoter region of interleukin-6 gene with an increased recruitment of HDAC3, which highlights the importance of the balance between HATs and histone deacetylases in the NF-KB-mediated inflammatory signaling pathway. Importantly, EGCG at 50 Mmol/L dose completely blocks EBV infection-induced cytokine expression and subsequently the EBV-induced B lymphocyte transformation. These results show the crucial role of acetylation in the development of inflammatory-related diseases. [Cancer Res 2009;69(2):583-92]

Lysyl oxidase-like 2 (LOXL2) is associated with invasiveness and metastasis in breast cancer. We analyzed the prognostic impact of LOXL2 for breast cancer patients and investigated the role of LOXL2 in breast cancer cell lines. Immunohistochemical study of LOXL2 expression was done in samples from 309 patients. Survival analysis was performed using log-rank test and Cox regression hazard model. After identification of LOXL2 expression in breast cancer cell lines, we performed matrigel invasion and wound-healing assays with LOXL2-silenced cell lines. In the human study, LOXL2 was expressed in 16.2 % of patients. Comparing the LOXL2-positive versus negative groups, there was a significantly higher proportion of estrogen receptor-negative patients (54.0 vs. 37.0 %, respectively; p = 0.029) and triple-negative patients (34.0 vs. 18.0 %; p = 0.022) in the positive group. In multivariate analysis for overall survival and metastasis-free survival, positive LOXL2 was demonstrated as a poor prognostic factor (HR 2.27 and 2.10, respectively). In vitro study indicated that LOXL2 silencing induces a mesenchymal-epithelial transition-like process in basal cell lines (MDA-MB-231 and BT549) associated with decreased invasive and migratory properties. These clinical and preclinical data confirm that higher LOXL2 expression is associated with invasiveness of basal-like breast cancer cells and lower survival of breast cancer patients. Our results suggest the clinical value of LOXL2 as a therapeutic target in breast cancer.

Although multiple studies have revealed that gallic acid plays an important role in the inhibition of malignant transformation, cancer development, and inflammation, the molecular mechanism of gallic acid in inflammatory diseases is still unclear. In this study, we identified gallic acid from Rosa rugosa as a histone acetyltransferase (HAT) inhibitor with global specificity for the majority of HAT enzymes, but with no activity toward epigenetic enzymes including sirtuin (silent mating type information regulation 2 homologue) 1 (S. cerevisiae), histone deacetylase, and histone methyltransferase. Enzyme kinetic studies indicated that gallic acid uncompetitively inhibits p300/CBP-dependent HAT activities. We found that gallic acid inhibits p300-induced p65 acetylation, both in vitro and in vivo, increases the level of cytosolic IκBα, prevents lipopolysaccharide (LPS)-induced p65 translocation to the nucleus, and suppresses LPS-induced nuclear factor-κB activation in A549 lung cancer cells. We have also shown that gallic acid treatment inhibits the acetylation of p65 and the LPS-induced serum levels of interleukin-6 in vivo. Importantly, gallic acid generally inhibited inflammatory responses caused by other stimuli, including LPS, IFN-γ, and interleukin-1β, and further downregulated the expression of nuclear factor-κB-regulated antiapoptotic genes. These results show the crucial role of acetylation in the development of inflammatory diseases. (Mol Cancer Res 2009;7(12):2011-21)