THU-449-Nuclear orphan receptor COUP-TF2 increases the resistence to anoikis and induces amoeboid movment and metastatic potential in hepatocellular carcinoma

Nuclear orphan receptor COUP-TF2 increases the resistence toanoikis and induces amoeboid movment and metastatic potentialin hepatocellular carcinomaElisabetta Ceni1, Tommaso Mello2, Simone Polvani3, Mirko Tarocchi2,Mireille Vasseur-Cognet4, Stefano Milani2, Andrea Galli2.1Departmentof Experimental and Clinical Biomedical Sciences“Mario Serio”University of Florence, Florence, Italy;2Department of Experimental andClinical Biomedical Sciences“Mario Serio”Florence, Italy;3d, Florence,Italy;4Institut Cochin, Paris, FranceEmail: elisabetta.ceni@unifi.itBackground and aims:Hepatocellularcarcinoma (HCC) isthe secondcause of cancer-related death worldwide. In the last few years, therole of nuclear receptors in hepatocarcinogenesis has received greatattention. The orphan nuclear receptor COUP-TF2 regulates import-ant biological processes such as glucose and lipid metabolichomeostasis. Recent studies indicate that COUP-TF2 is a pro-oncogenic factor but its role in HCC is still controversial. Aim of thisstudy was to evaluate the role of COUP-TF2 in HCC.Method:COUP-TFII expression on primary HCC samples wasevaluated by immunohistochemistry. Overexpressing COUP-TFII HCCcellslineswerecreatedthroughstabletransfectionwithpcR3.1/COUP-TF2 (Hepa1–6/COUP-TF2, HuH7/COUP-TF2, HepG2/COUP-TF2). Themigration and the ability to colonize sites at a distance from thegrowth front were evaluated by Time-Laps microscopy. Finally, westudied the role of COUP-TFII in an in vivo models of mousecarcinogenesis (TgN (Alb1HBV)44Bri) realizing a triple transgenicanimal where the liver-specific Cre expression deletes COUP-TF2 inhepatocytesandinxenograftmodelwheremicewereinoculatedwithhuman smmc7721 hepatocarcinoma cells stable transfected withCOUP-TF2 or silenced by specific short hairpin.Results:COUP-TFII is over-expressed in primary HCC samples andKaplan-Meier and Cox regression analysis show that it may be anindependent prognostic factor of worst outcome. Overexpression ofCOUP-TF2 has no significant effects on cell proliferation, but Live cellimaging experiments showed that COUP-TF2 induces a pro-meta-static phenotype characterized by an increased resistance to anoikisand amoeboid migration. Moreover, we found that several proteinsinvolved in the organization of the cytoskeleton, cell-cell or cell-substrate adhesion (i.e. FAK, P-FAK, T-cadherin,β-catenin,αV-integrin, VCAM andα-tubulin), were differently modulated inCOUP-TF2 overexpressingvscontrol cells. Finally, COUP-TF2 deletionin hepatocytes of HBV-transgenic mice (Tg[HBV]CreKOCOUP-TF2)reduces tumour growth and in xenograft model reduces pulmonarymetastasis compared to control animals.Conclusion:Our study uncovers COUP-TFII as a critical new player inhepatocarcinogenesis and HCC progression. The evidence that COUP-TFII deletion has a little impact in adult physiological functions andits transcriptional activity could be potentially regulated by ligands,indicates that this nuclear receptor is a promising target for HCCtherapy