Summary Polycomb Repressive Complexes (PRC1 and PRC2) mediated epigenetic regulation is critical for maintaining cellular homeostasis. Members of Polycomb Group (PcG) proteins including EZH2, a PRC2 component, are up-regulated in various cancer types, implicating their role in tumorigenesis. Here, we have identified several microRNAs (miRNAs) that are repressed by EZH2. These miRNAs in turn regulate the expression of PRC1 proteins, BMI1 and RING2. We found that ectopic overexpression of EZH2-regulated miRNAs attenuated cancer cell growth and invasiveness, and abrogated cancer stem cell properties. Importantly, expression analysis revealed an inverse correlation between miRNA and PRC protein levels in cell culture and prostate cancer tissues. Taken together, our data has uncovered a coordinate regulation of PRC1 and PRC2 activities that is mediated by miRNAs.

Polycomb Repressive Complexes 1 and 2 (PRC1 and 2) play a critical role in the epigenetic regulation of transcription during cellular differentiation, stem cell pluripotency, and neoplastic progression. Here we show that the Polycomb Group protein EED, a core component of PRC2, physically interacts with and functions as part of PRC1. Components of PRC1 and PRC2 compete for EED binding. EED functions to recruit PRC1 to H3K27me3 loci and enhances PRC1 mediated H2A ubiquitin E3 ligase activity. Taken together, we suggest an integral role for EED as an epigenetic exchange factor coordinating the activities of PRC1 and 2.

Background-The aim of our study was to compare myocardial mechanics of constrictive pericarditis (CP) with restrictive cardiomyopathy (RCM), or healthy controls; to assess the impact of pericardial thickening detected by cardiac magnetic resonance on regional myocardial mechanics in CP; and to quantitate the effect of pericardiectomy on myocardial mechanics in CP. Methods and Results-Myocardial mechanics were evaluated by 2-dimensional speckle tracking in 52 consecutive patients with CP who underwent cardiac magnetic resonance examination before pericardiectomy, 35 patients with RCM, and 26 control subjects. CP patients had selectively depressed left ventricular (LV) anterolateral wall strain (LWS) and right ventricular (RV) free wall longitudinal systolic strain (FWS) but preserved LV septal wall systolic strain (SWS

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