Decreased expression of JMJD3 predicts poor prognosis of patients with clear cell renal cell carcinoma

Previous studies have demonstrated abnormal H3K27 methylation status during clear cell renal cell carcinoma (ccRCC) carcinogenesis, and have suggested that the histone H3K27 demethylases, jumonji domain-containing protein 3 (JMJD3) and ubiquitously-transcribed TPR gene on the X chromosome, are important regulatory factors that alter H3K27 methylation status. The present study aimed to explore the prognostic value of JMJD3 in patients with ccRCC. A total of 331 ccRCC samples were stained for JMJD3 by immunohistochemistry. Stage, Size, Grade and Necrosis (SSIGN) and University of California Los Angeles Integrated Staging System (UISS) scores were applied to stratify risks. Survival analyses were performed through the Kaplan-Meier estimator method and Cox proportional hazard model. The results revealed that JMJD3 expression in ccRCC was significantly increased compared with that in the peritumoral tissue (P<0.001) and negatively associated with a number of other clinicopathological characteristics. Kaplan-Meier estimator and multivariate analyses revealed that decreased tumoral JMJD3 expression was associated with OS (hazard ratio, 2.141; P=0.003), and DFS prediction (hazard ratio, 1.737; P=0.033). In addition, following stratification of patients into three risk levels using the SSIGN and UISS scores, decreased tumoral JMJD3 expression was associated with shorter OS (P=0.003 for SSIGN and UISS scores) and DFS (P=0.007 for SSIGN and P=0.041 for UISS score) in the intermediate risk groups. The results from the present study suggest that JMJD3 is a novel prognostic marker for patients with ccRCC and is of particular significance in patients with intermediate-risk disease.

Ezh1 and Ezh2 differentially regulate PSD-95 gene transcription in developing hippocampal neurons

Polycomb Repressive Complex 2 (PRC2) mediates transcriptional silencing by catalyzing histone H3 lysine 27 trimethylation (H3K27me3), but its role in the maturation of postmitotic mammalian neurons remains largely unknown. We report that the PRC2 paralogs Ezh1 and Ezh2 are differentially expressed during hippocampal development. We show that depletion of Ezh2 leads to increased expression of PSD-95, a critical plasticity gene, and that reduced PSD-95 gene transcription is correlated with enrichment of Ezh2 at the PSD-95 gene promoter; however, the H3K27me3 epigenetic mark is not present at the PSD-95 gene promoter, likely due to the antagonizing effects of the H3S28P and H3K27Ac marks and the activity of the H3K27 demethylases JMJD3 and UTX. In contrast, increased PSD-95 gene transcription is accompanied by the presence of Ezh1 and elongation-engaged RNA Polymerase II complexes at the PSD-95 gene promoter, while knock-down of Ezh1 reduces PSD-95 transcription. These results indicate that Ezh1 and Ezh2 have antagonistic roles in regulating PSD-95 transcription.