Evaluation of the in vitro and in vivo antitumor activity of histone deacetylase inhibitors for the therapy of retinoblastoma

Clin Cancer Res. 2008 May 15;14(10):3113-23. doi: 10.1158/1078-0432.CCR-07-4836.


Purpose: To evaluate the potential utility of histone deacetylase inhibitors (HDACi) for treatment of retinoblastoma (RB).

Experimental design: Growth-inhibitory effects of HDACi [trichostatin A (TSA), suberoylanilide hydroxamic acid (SAHA), or MS-275] were assessed in human and transgenic murine RB cells. Effects of TSA and MS-275 were also assessed in combination with standard therapeutic agents for RB. Proapoptotic effects of MS-275 and TSA were evaluated by caspase-3/7 activity, Annexin V translocation, and/or Bim expression analyses. Effects of MS-275 on cell cycle distribution and reactive oxygen species levels were determined by flow cytometry. Retinal tissue morphology was evaluated in mice after local administration of MS-275. Analysis of retinal acetyl-histone levels was used to assess MS-275 delivery after systemic administration. Therapeutic effects of MS-275 were determined in transgenic mouse and rat ocular xenograft models of RB after i.p. injection of 20 mg/kg every other day for 21 or 13 days, respectively.

Results: TSA, SAHA, and MS-275 dose dependently reduced RB cell survival. TSA and MS-275 showed additive growth-inhibitory effects in combination with carboplatin, etoposide, or vincristine. TSA and MS-275 increased caspase-3/7 activity. MS-275 increased Annexin V membrane translocation and induced G1 arrest. Cytotoxicity of MS-275 was dependent on increased reactive oxygen species levels and was reversed by antioxidant pretreatment. Intraocular administration of 1 microL of 10 micromol/L MS-275 did not alter ocular tissue morphology. Increased acetyl-histone levels confirmed MS-275 delivery to retinal tissue after systemic administration. MS-275 significantly reduced tumor burden in both mouse and rat models of RB.

Conclusions: HDACi should be considered for clinical trials in children with RB.

Publication types

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

MeSH terms

  • Animals
  • Annexin A5 / drug effects
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Benzamides / pharmacology
  • Blotting, Western
  • Caspase 3 / drug effects
  • Caspase 7 / drug effects
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Enzyme Inhibitors / pharmacology*
  • Flow Cytometry
  • Histone Deacetylase Inhibitors*
  • Humans
  • Hydroxamic Acids / pharmacology
  • In Vitro Techniques
  • Mice
  • Mice, Transgenic
  • Polymerase Chain Reaction
  • Pyridines / pharmacology
  • Rats
  • Reactive Oxygen Species / metabolism
  • Retinal Neoplasms / drug therapy*
  • Retinoblastoma / drug therapy*
  • Vorinostat
  • Xenograft Model Antitumor Assays


  • Annexin A5
  • Antineoplastic Agents
  • Benzamides
  • Enzyme Inhibitors
  • Histone Deacetylase Inhibitors
  • Hydroxamic Acids
  • Pyridines
  • Reactive Oxygen Species
  • entinostat
  • trichostatin A
  • Vorinostat
  • Caspase 3
  • Caspase 7