Disruption of tubular Flcn expression as a mouse model for renal tumor induction

Kidney Int. 2015 Nov;88(5):1057-69. doi: 10.1038/ki.2015.177. Epub 2015 Jun 17.

Abstract

The study of kidney cancer pathogenesis and its treatment has been limited by the scarcity of genetically defined animal models. The FLCN gene that codes for the protein folliculin, mutated in Birt-Hogg-Dubé syndrome, presents a new target for mouse modeling of kidney cancer. Here we developed a kidney-specific knockout model by disrupting the mouse Flcn in the proximal tubules, thus avoiding homozygous embryonic lethality or neonatal mortality, and eliminating the requirement of loss of heterozygosity for tumorigenesis. This knockout develops renal cysts and early onset (6 months) of multiple histological subtypes of renal neoplasms featuring high tumor penetrance. Although the majority of the tumors were chromophobe renal cell carcinomas in affected mice under 1 year of age, papillary renal cell carcinomas predominated in the kidneys of older knockout mice. This renal neoplasia from cystic hyperplasia at 4 months to high-grade renal tumors by 16 months represented the progression of tumorigenesis. The mTOR and TGF-β signalings were upregulated in Flcn-deficient tumors, and these two activated pathways may synergetically cause renal tumorigenesis. Treatment of knockout mice with the mTOR inhibitor rapamycin for 10 months led to the suppression of tumor growth. Thus, our model recapitulates human Birt-Hogg-Dubé kidney tumorigenesis, provides a valuable tool for further study of Flcn-deficient renal tumorigenesis, and tests new drugs/approaches to their treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibiotics, Antineoplastic / therapeutic use
  • Carcinogenesis / genetics
  • Carcinoma, Renal Cell / drug therapy
  • Carcinoma, Renal Cell / genetics*
  • Carcinoma, Renal Cell / metabolism
  • Carcinoma, Renal Cell / pathology*
  • Cysts / genetics
  • Cysts / pathology*
  • Disease Models, Animal*
  • Hyperplasia / pathology
  • Kidney Neoplasms / drug therapy
  • Kidney Neoplasms / genetics*
  • Kidney Neoplasms / metabolism
  • Kidney Neoplasms / pathology*
  • Kidney Tubules, Proximal / pathology*
  • Mice
  • Mice, Knockout
  • Proto-Oncogene Proteins / genetics*
  • Signal Transduction
  • Sirolimus / therapeutic use
  • TOR Serine-Threonine Kinases / antagonists & inhibitors
  • TOR Serine-Threonine Kinases / metabolism
  • Transforming Growth Factor beta / metabolism
  • Tumor Suppressor Proteins / genetics*

Substances

  • Antibiotics, Antineoplastic
  • Bhd protein, mouse
  • Proto-Oncogene Proteins
  • Transforming Growth Factor beta
  • Tumor Suppressor Proteins
  • mTOR protein, mouse
  • TOR Serine-Threonine Kinases
  • Sirolimus