Epigenetic regulation of CLCA2 by CtBP1, HDACs, ZEB1 and miRNAs impacts on prostate cancer cell adhesion.

PORRETTI J; MASSILLO CL; DALTON N; LANTELME MR; SEGURA LA; CABANILLAS AM; DE LUCA P; DE SIERVI A

Mar del Plata

Congreso; LXI Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2016

Sociedad Argentina de Investigación Clínica

Epidemiologic studies demonstrated that metabolic syndrome (MeS) increased prostate cancer (PCa) risk and aggressiveness. Our previous studies showed that MeS and the C-terminal binding protein 1 (CtBP1) cooperate to induce PCa growth in mice. Genome-wide expression profiles and Gene Set Enrichment Analysis (GSEA) from these tumors, identified to chloride channel acccessory 2 (CLCA2) as a key CtBP1-repressed gene. CLCA2 was described as a tumor suppressor gene that links cell adhesion to cytosolic signaling proteins implicated in breast cancer EMT. We also found that CtBP1 associates to CLCA2 promoter and represses its expression in vivo and in vitro. The goal of this work was to understand the biological relevance and the molecular mechanisms whereby the transcriptional co-regulator CtBP1 represses CLCA2. PC3 cells were co- transfected with CtBP1, the promoter CLCA2 reporter plasmid and the Zn Finger E-box binding homeobox 1 (ZEB1), p65 or different histone deacetylases (HDACs) expression plasmids. We found that CLCA2 promoter activity was not modulated by p65, whereas ZEB1, HDAC2 or HDAC3 together with CtBP1 synergistically repressed CLCA2 promoter activity. Moreover, the HDAC inhibitor (TSA) significantly increased CLCA2 promoter activity and expression. We hybridized a miRNA expression microarray from PCa xenografts grown in MeS mice. After normalization and bioinformatic data analysis, we found several miRNAs that target CLCA2. Among them, the CtBP1-induced hsa-miR-196b, stands out for its role in oral and gastric cancer cell invasion. Thus, we assessed miR196b/CLCA2 role in cell adhesion. miR-196b overexpression decreased PC3 cell adhesion, while CLCA2 promoted cell adhesion in these cells. In turn, CLCA2 depletion dramatically decreased cell adhesion. In summary, this study describes for the first time that CLCA2 is epigenetically regulated by HDACs, ZEB1, miRNAs and CtBP1 in PCa cells modulating PCa cell adhesion.