Inhibition of leydig tumor growth by farnesoid X receptor activation: The in vitro and in vivo basis for a novel therapeutic strategy

Stefania Catalano, Salvatore Panza, Rocco Malivindi, Cinzia Giordano, Ines Barone, Gianluca Bossi, Marilena Lanzino, Rosa Sirianni, Loredana Mauro, Diego Sisci, Daniela Bonofiglio, Sebastiano Andò

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16 Scopus citations

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 p21WAF1/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. What's new? Leydig cell tumors are the most common tumors of the gonadal stroma, and currently there are no effective ways to treat such tumors should they be malignant. Farnesoid X receptors (FXR) are expressed in Leydig tumor cells, and here the authors show that FXR activation through synthetic ligands reduces tumor growth. The mechanism involves both inhibition of cell proliferation and induction of apoptosis, with an underlying increase of p53 gene expression. This study provides the first direct evidence for in vivo effects of FXR activation on Leydig carcinogenesis, suggesting that FXR ligands could potentially be used in a clinical approach.

Original languageEnglish (US)
Pages (from-to)2237-2247
Number of pages11
JournalInternational Journal of Cancer
Volume132
Issue number10
DOIs
StatePublished - May 15 2013

Keywords

  • Farnesoid X receptor
  • Leydig tumors
  • NF-kB
  • apoptosis
  • p53

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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    Catalano, S., Panza, S., Malivindi, R., Giordano, C., Barone, I., Bossi, G., Lanzino, M., Sirianni, R., Mauro, L., Sisci, D., Bonofiglio, D., & Andò, S. (2013). Inhibition of leydig tumor growth by farnesoid X receptor activation: The in vitro and in vivo basis for a novel therapeutic strategy. International Journal of Cancer, 132(10), 2237-2247. https://doi.org/10.1002/ijc.27915