title: Inhibition of Leydig tumor growth by farnesoid X receptor activation: the in vitro and in vivo basis for a novel therapeutic strategy.
abstract: Leydig cell tumors (LCTs) are the most common tumors of the gonadal stroma and represent about 3% of all testicular neoplasms. In most cases, LCTs are benign; however, if the tumor is malignant, no effective treatments are currently available. We have recently reported that farnesoid X receptor (FXR) is expressed in R2C Leydig tumor cells, and it reduces the estrogen-dependent cell proliferation by negatively regulating aromatase expression. Here, we demonstrated that treatment with GW4064, a specific FXR agonist, markedly reduced Leydig tumor growth in vivo by inhibiting proliferation and inducing apoptosis. Indeed, the tumors from GW4064-treated mice exhibited a decrease in the expression of the proliferation marker Ki-67 and aromatase along with an increase in the apoptotic nuclei. FXR activation induced an enhanced poly(ADP-ribose) polymerase cleavage, a marked DNA fragmentation and a strong increase in TUNEL-positive R2C cells also in vitro. Moreover, in both in vivo and in vitro models, FXR ligands upregulated mRNA and protein levels of p53 and of its downstream effector p21(WAF1/Cip1) . Functional experiments showed that FXR ligands upregulated p53 promoter activity and this occurred through an increased binding of FXR/nuclear factor-kB (NF-kB) complex to the NF-kB site located within p53 promoter region as revealed by electrophoretic mobility shift assay and chromatin immunoprecipitation analysis. Taken together, results from our study show, for the first time, that treatment with FXR ligands induces Leydig tumor regression in vivo, suggesting that activation of FXR may represent a promising therapeutic strategy for LCTs.
authors.affiliation: Department of Pharmaco-Biology, University of Calabria, Arcavacata di Rende (CS), Italy. stefcatalano@libero.it
authors.forename: Stefania
authors.initials: S
authors.lastname: Catalano
authors.forename: Salvatore
authors.initials: S
authors.lastname: Panza
authors.forename: Rocco
authors.initials: R
authors.lastname: Malivindi
authors.forename: Cinzia
authors.initials: C
authors.lastname: Giordano
authors.forename: Ines
authors.initials: I
authors.lastname: Barone
authors.forename: Gianluca
authors.initials: G
authors.lastname: Bossi
authors.forename: Marilena
authors.initials: M
authors.lastname: Lanzino
authors.forename: Rosa
authors.initials: R
authors.lastname: Sirianni
authors.forename: Loredana
authors.initials: L
authors.lastname: Mauro
authors.forename: Diego
authors.initials: D
authors.lastname: Sisci
authors.forename: Daniela
authors.initials: D
authors.lastname: Bonofiglio
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Andò
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001141:Aromatase / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D015151:Immunoblotting; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D007555:Isoxazoles / Q000008:administration & dosage / Q000494:pharmacology*; D007984:Leydig Cell Tumor / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000378:metabolism; D011897:Random Allocation; D060888:Real-Time Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013736:Testicular Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D023041:Xenograft Model Antitumor Assays; D054462:p21-Activated Kinases / Q000378:metabolism; D000099150:Receptor, Farnesoid X-Activated
chemical_list: D000970:Antineoplastic Agents; D001141:Aromatase; D007555:Isoxazoles; D016328:NF-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D016159:Tumor Suppressor Protein p53; D054462:p21-Activated Kinases; D000099150:Receptor, Farnesoid X-Activated; C515905:Pak1 protein, mouse; C412815:GW 4064