Loss of Hfe leads to progression of tumor phenotype in primary retinal pigment epithelial cells

Invest Ophthalmol Vis Sci. 2013 Jan 7;54(1):63-71. doi: 10.1167/iovs.12-10312.


Purpose: Hemochromatosis is a disorder of iron overload arising mostly from mutations in HFE. HFE is expressed in retinal pigment epithelium (RPE), and Hfe(-/-) mice develop age-related iron accumulation and retinal degeneration associated with RPE hyperproliferation. Here, the mechanism underlying the hyperproliferative phenotype in RPE was investigated.

Methods: Cellular senescence was monitored by β-galactosidase activity. Gene expression was monitored by real-time PCR. Survivin was analyzed by Western blot and immunofluorescence. Migration and invasion were monitored using appropriate kits. Glucose transporters (GLUTs) were monitored by 3-O-methyl-D-glucose uptake. Histone deacetylases (HDACs) were studied by monitoring catalytic activity and acetylation status of histones H3/H4.

Results: Hfe(-/-) RPE cells exhibited slower senescence rate and higher survivin expression than wild type cells. Hfe(-/-) cells migrated faster and showed greater glucose uptake and increased expression of GLUTs. The expression of HDACs and DNA methyltransferase (DNMTs) also was increased. Similarly, RPE cells from hemojuvelin (Hjv)-knockout mice, another model of hemochromatosis, also had increased expression of GLUTs, HDACs, and DNMTs. The expression of Slc5a8 was decreased in Hfe(-/-) RPE cells, but treatment with a DNA methylation inhibitor restored the transporter expression, indicating involvement of DNA methylation in the silencing of Slc5a8 in Hfe(-/-) cells.

Conclusions: RPE cells from iron-overloaded mice exhibit several features of tumor cells: decreased senescence, enhanced migration, increased glucose uptake, and elevated levels of HDACs and DNMTs. These features are seen in Hfe(-/-) RPE cells as well as in Hjv(-/-) RPE cells, providing a molecular basis for the hyperproliferative phenotype of Hfe(-/-) and Hjv(-/-) RPE cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Transport Systems / genetics
  • Animals
  • Cation Transport Proteins / genetics
  • Cell Movement / physiology
  • Cell Transformation, Neoplastic / pathology
  • Cellular Senescence / physiology
  • DNA Methylation / physiology
  • Disease Progression
  • Eye Neoplasms* / genetics
  • Eye Neoplasms* / pathology
  • Eye Neoplasms* / physiopathology
  • Female
  • Glucose / pharmacokinetics
  • Hemochromatosis Protein
  • Hemochromatosis* / genetics
  • Hemochromatosis* / pathology
  • Hemochromatosis* / physiopathology
  • Histocompatibility Antigens Class I / genetics*
  • Inhibitor of Apoptosis Proteins / metabolism
  • Male
  • Membrane Proteins / genetics*
  • Mice
  • Mice, 129 Strain
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Nude
  • Monocarboxylic Acid Transporters
  • Phenotype
  • Plasma Membrane Neurotransmitter Transport Proteins / genetics
  • Primary Cell Culture
  • Repressor Proteins / metabolism
  • Retinal Pigment Epithelium / pathology*
  • Retinal Pigment Epithelium / physiopathology*
  • Survivin
  • Transplantation, Heterologous


  • Amino Acid Transport Systems
  • Birc5 protein, mouse
  • Cation Transport Proteins
  • Hemochromatosis Protein
  • Hfe protein, mouse
  • Histocompatibility Antigens Class I
  • Inhibitor of Apoptosis Proteins
  • Membrane Proteins
  • Monocarboxylic Acid Transporters
  • Plasma Membrane Neurotransmitter Transport Proteins
  • Repressor Proteins
  • Slc5a8 protein, mouse
  • Slc6A14 protein, mouse
  • Survivin
  • Glucose