PKC zeta (Phospho-Thr560) ELISA Kit

Peroxisome proliferator-activated receptor (PPAR) belongs to the nuclear hormone receptor superfamily. Recently published reports demonstrate the importance of a direct repeat 2 (DR2) as a PPAR gamma-responsive element in addition to the canonical direct repeat 1 (DR1) Peroxisome proliferator response elements (PPREs). However, a comprehensive and systematic approach to constructing de novo disease-specific gene networks for PPAR gamma is lacking, especially one that includes PPAR gamma target genes containing either DR1 or DR2 site within their promoter region. Here, we computationally identified 1154 PPAR gamma direct target genes and constructed the PPAR gamma disease gene network, which revealed 138 PPAR gamma target genes that are associated with 65 unique diseases. The network shows that PPAR gamma target genes are highly associated with cancer and neurological diseases. Thirty-eight PPAR gamma direct target genes were found to be involved in prostate cancer and two key (hub) PPAR gamma direct target genes, PRKCZ and PGK1, were experimentally validated to be repressed upon PPAR gamma activation by its natural ligand, 15d-PGJ(2) in three prostrate cancer cell lines. We proposed that PRKCZ and PGK1 could be novel therapeutic targets for prostate cancer. These investigations would not only aid in understanding the molecular mechanisms by which PPAR gamma regulates disease targets but would also lead to the identification of novel PPAR gamma gene targets.

Cyclooxygenase (COX)-2 is upregulated in hepatocellular carcinoma (HCC). However, the direct causative effect of COX-2 in spontaneous HCC formation remains unknown. We thus investigate the role and molecular pathogenesis of COX-2 in HCC by using liver-specific COX-2 transgenic (TG) mice. We found spontaneous HCC formation with elevated inflammatory infiltrates and neovessels in male TG mice (3/21, 14.3%), but not in any of male WT mice (0/19). Reduced representation bisulfite sequencing (RRBS) and gene expression microarrays were performed in the HCC tumor and non-HCC liver tissues to investigate the molecular mechanisms of COX-2-driven HCC. By RRBS, DNA promoter hypermethylation was identified in HCC from TG mice. Induction of promoter hypermethylation was associated with reduced tet methylcytosine dioxygenase 1 (TET1) expression by COX-2. TET1 could catalyze the conversion of 5-methylcytosine into 5-hydroxymethylcytosine (5hmC) and prevents DNA hypermethylation. In keeping with this, loss of 5hmC was demonstrated in COX-2-induced HCC. Consistently, COX-2 overexpression in human HCC cell lines could reduce both TET1 expression and 5hmc levels. Integrative analyses of DNA methylation and gene expression profiles further identified significantly downregulated genes including LTBP1, ADCY5 and PRKCZ by promoter methylation in COX-2-induced HCC. Reduced expression of LTBP1, ADCY5 and PRKCZ by promoter hypermethylation was further validated in human HCCs. Bio-functional investigation revealed that LTBP1 inhibited cell proliferation in HCC cell lines, suggesting its potential role as a tumor suppressor in HCC. Gene expression microarrays revealed that signaling cascades (AKT (protein kinase B), STK33 (Serine/Threonine kinase 33) and MTOR (mechanistic target of rapamycin) pathways) were enriched in COX-2-induced HCC. In conclusion, this study demonstrated for the first time that enhanced COX-2 expression in hepatocytes is sufficient to induce HCC through inducing promoter hypermethylation by reducing TET1, silencing tumor-suppressive genes and activating key oncogenic pathways. Inhibition of COX-2 represents a mechanism-based target for HCC prevention.