Epidemiological studies suggest that the incidence of CVD and postmenopausal osteoporosis is low in the Mediterranean area, where herbs and nuts, among others, play an important role in nutrition. In the present study, we sought a role of walnuts (Juglans regia L.) in endothelial and bonecell function. As the endothelial cell expression of adhesion molecules has been recognised as an early step in inflammation and atherogenesis, we examined the effect of walnut methanolic extract and ellagic acid, one of its major polyphenolic components (as shown by HPLC analysis), on the expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in human aortic endothelial cells. After incubating the cells with TNF-a (1 ng/ml) in the absence and in the presence of walnut extract (10-200 mg/ml) or ellagic acid (10 27 -10 25 M), the VCAM-1 and ICAM-1 expression was quantified by cell-ELISA. We further evaluated the effect of walnut extract (10 -50 mg/ml), in comparison with ellagic acid (10 29 -10 26 M), on nodule formation in the osteoblastic cell line KS483.Walnut extract and ellagic acid decreased significantly the TNF-a-induced endothelial expression of both VCAM-1 and ICAM-1 (P, 0·01; P,0·001). Both walnut extract (at 10-25 mg/ml) and ellagic acid (at 10 29 -10 28 M) induced nodule formation in KS483 osteoblasts. The present results suggest that the walnut extract has a high anti-atherogenic potential and a remarkable osteoblastic activity, an effect mediated, at least in part, by its major component ellagic acid. Such findings implicate the beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.

In this report we determine the ability of ursolic acid (UA) to induce apoptosis and to modulate glucocorticoid receptor (GR) and Activator Protein-1 (AP-1) in MCF-7 cells. The UA-induced apoptosis (53 microM), the PARP cleavage, and the decrease in Bcl-2 protein (53 microM) support the notion that UA induces apoptosis through the intrinsic mitochondrial pathway. UA binds GR (relative binding affinity: 2.57) and translocates GR into nucleus, suggesting its potential as a GR modulator. UA had no effect on GRE- or TRE-driven gene expression. In summary, UA is a GR modulator and may be considered as a potential anticancer agent in breast cancer.

Estrogen signaling can occur through a nonclassical pathway involving the interaction of estrogen receptors (ER) with other transcription factors such as activator protein-1 (AP-1) and SP-1. However, there is little mechanistic understanding about this pathway, with conflicting results from in vitro investigations. In this study, we applied the ChIP-on-chip approach to identify ERβ-binding sites on a genome-wide scale, identifying 1,457 high-confidence binding sites in ERβ-overexpressing MCF7 breast cancer cells. Genes containing ERβ-binding sites can be regulated by E2. Notably, ∼60% of the genomic regions bound by ERβ contained AP-1-like binding regions and estrogen response element-like sites, suggesting a functional association between AP-1 and ERβ signaling. Chromatin immunoprecipitation (ChIP) analysis confirmed the association of AP-1, which is composed of the oncogenic transcription factors c-Fos and c-Jun, to ERβ-bound DNA regions. Using a re-ChIP assay, we showed co-occupancy of ERβ and AP-1 on chromatin. Short interfering RNA-mediated knockdown of c-Fos or c-Jun expression decreased ERβ recruitment to chromatin, consistent with the role of AP-1 in mediating estrogen signaling in breast cancer cells. Additionally, ERα and ERβ recruitment to AP-1/ERβ target regions exhibited gene-dependent differences in response to antiestrogens. Together, our results broaden insights into ERβ DNA-binding at the genomic level by revealing crosstalk with the AP-1 transcription factor. Cancer Res; 70(12); 5174-83. ©2010 AACR.