The success of pharmacological treatments in primary liver cancers is limited by the marked efficacy of mechanisms of chemoresistance already present in hepatocytes. The role of the nuclear receptor FXR is unclear. Although, in non-treated liver tumors, its expression is reduced, the refractoriness to anticancer drugs is high. Moreover, the treatment with cisplatin up-regulates FXR. The aim of this study was to investigate whether FXR is involved in stimulating chemoprotection/chemoresistance in healthy and tumor liver cells. In human hepatocytes, the activation of FXR with the agonist GW4064 resulted in a significant protection against cisplatin-induced toxicity. In human hepatoma Alexander cells, with negligible endogenous expression of FXR, GW4064 also protected against cisplatin-induced toxicity, but only if they were previously transfected with FXR/RXR. Investigation of 109 genes potentially involved in chemoresistance revealed that only ABCB4, TCEA2, CCL14, CCL15 and KRT13 were up-regulated by FXR activation both in human hepatocytes and FXR/RXR-expressing hepatoma cells. In both models, cisplatin, even in the absence of FXR agonists, such as bile acids and GW4064, was able to up-regulate FXR targets genes, which was due to FXR-mediated trans-activation of response elements in the promoter region. FXR-dependent chemoprotection was also efficient against other DNA-damaging compounds, such as doxorubicin, mitomycin C and potassium dichromate, but not against non-genotoxic drugs, such as colchicine, paclitaxel, acetaminophen, artesunate and sorafenib. In conclusion, ligand-dependent and independent activation of FXR stimulates mechanisms able to enhance the chemoprotection of hepatocytes against genotoxic compounds and to reduce the response of liver tumor cells to certain pharmacological treatments. © 2013 Elsevier B.V. ; This study was supported in part by the Ministerio de Ciencia e Innovación (grant SAF2010-15517); the Instituto de Salud Carlos III, FIS (grant PI11/0337) and the Junta de Castilla y Leon (grants SA023A11-2, SA070A11-2 and Biomedicina-2011), Spain. The group is a member of the Network for Cooperative Research on Membrane Transport Proteins (REIT), co-funded by the Ministerio de Educación y Ciencia, Spain and the European Regional Development Fund (ERDF) (grant BFU2007-30688-E/BFI) and belongs to the CIBERehd (Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas), Instituto de Salud Carlos III, Spain. Javier Vaquero is a recipient of a predoctoral fellowship from the Ministerio de Educacion, Spain (grant AP2007−00105). ; Peer Reviewed