Transcriptionally Active Androgen Receptor Splice Variants Promote Hepatocellular Carcinoma Progression

Cancer Res. 2020 Feb 1;80(3):561-575. doi: 10.1158/0008-5472.CAN-19-1117. Epub 2019 Nov 4.

Abstract

Owing to the marked sexual dimorphism of hepatocellular carcinoma (HCC), sex hormone receptor signaling has been implicated in numerous aspects of liver cancer pathogenesis. We sought to reconcile the clear contribution of androgen receptor (AR) activity that has been established in preclinical models of HCC with the clinical failure of AR antagonists in patients with advanced HCC by evaluating potential resistance mechanisms to AR-targeted therapy. The AR locus was interrogated for resistance-causing genomic modifications using publicly available primary HCC datasets (1,019 samples). Analysis of HCC tumor and cell line RNA-seq data revealed enriched expression of constitutively active, treatment-refractory AR splice variants (AR-SV). HCC cell lines expressed C-terminal-truncated AR-SV; 28 primary HCC samples abundantly expressed AR-SV. Low molecular weight AR species were nuclear localized and constitutively active. Furthermore, AR/AR-SV signaling promoted AR-mediated HCC cell progression and conferred resistance to AR antagonists. Ligand-dependent and -independent AR signaling mediated HCC epithelial-to-mesenchymal transition by regulating the transcription factor SLUG. These data suggest that AR-SV expression in HCC drives HCC progression and resistance to traditional AR antagonists. Novel therapeutic approaches that successfully target AR-SVs may be therapeutically beneficial for HCC. SIGNIFICANCE: Treatment-refractory, constitutively active androgen receptor splice variants promote hepatocellular carcinoma progression by regulating the epithelial-to-mesenchymal transition pathway.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing*
  • Androgen Receptor Antagonists / pharmacology
  • Androgens / metabolism
  • Apoptosis
  • Biomarkers, Tumor / genetics*
  • Carcinoma, Hepatocellular / drug therapy
  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / pathology*
  • Cell Proliferation
  • Disease Progression
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Liver Neoplasms / drug therapy
  • Liver Neoplasms / genetics
  • Liver Neoplasms / pathology*
  • Male
  • Prognosis
  • Receptors, Androgen / genetics*
  • Signal Transduction
  • Tumor Cells, Cultured

Substances

  • AR protein, human
  • Androgen Receptor Antagonists
  • Androgens
  • Biomarkers, Tumor
  • Receptors, Androgen