New Therapeutic Strategies for Human Hepatocellular Carcinoma Based on Epigenetic Targeting.

BAYO FINA JM ; FIORE EJ; DOMINGUEZ L; MALVICINI M.; ATORRASAGASTI C.; GARCIA M; RODRIGUEZ MM; ONORATO A; MARTINEZ E; MAZZOLINI G

San Francisco

Congreso; The Liver Meeting 2018; 2018

Background: Hepatocarcinoma (HCC) is a major health problem and new therapeutic strategies are needed. Recently, a link between epigenetic alterations and carcinogenesis has been established. The aim of our work was to test the therapeutic potential of inhibition of epigenetic enzymes for HCC treatment.Methods: Public clinical and RNA-Seq data of human HCC (n=365) and non-tumor (n=50) tissues from The Cancer Genome Atlas (TCGA) were analyzed for gene expression, mutation and prognosis correlation analysis. Cell proliferations, cell cycle and cell death were evaluated by MTS, iodure propidium and Annexin V assays respectively. In vivo experiment was performed in an orthotopic murine model of HCC. For expression analysis, RNA-Seq on HCC cells treated with 3 different JmjC inhibitors (JIB-04, GSK-J4 or SD-70) was performed.Results: Analysis of TCGA data showed that 25% of bromodmains (BRD), 16% of acetyltransferases (HAT), 45% of methyltransferases (KMT) and 20% of demethylases (KDM) are enriched in HCC tumors vs non-tumor tissues. Moreover, at least one member of these enzymes is mutated in the 75% of the patients and that high expression of 1 of 8 BRDs, 1 of 18 HAT, 4 of 35 KMT and 5 of 29 KDM correlates with poor prognosis of patients. MTS assay showed that inhibitors of Jumonji C family (JmjCs) of KDMs (JIB-04, GSK-J4, SD-70, ML324), KMTs (BIX 1294, LLY-507) and BRD4 (JQ-1) have high antiproliferative activity on HCC cells. In addition, this subset of inhibitors induced a strong cell cycle arrest and cell death. In vivo experiments showed that JIB-04 has a strong antitumor activity after systemic administration. Gene ontology analysis of genes modulated by JmjC inhibitors showed and induction of transcription program related with inhibition of cell proliferation and induction of cell death on HCC cells. Moreover, analysis of TCGA data showed that several genes depleted by JmjC inhibitors are highly expressed in tumor vs non-tumor tissues and that their high expression correlates with a poor prognosis in patients. Finally, we identified a gene signature based on CENPA, KIF20A, PLK1, NCAPG and CTH expression that could be used for prognosis prediction and to define a group of high-risk patients that could be benefited by a therapy based on JmjC inhibitors.Conclusion: Our work highlights the importance of epigenetic alterations in HCC development, in patient prognosis and supports the research on epigenetic modifications as therapeutic targets.