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Transducible peptide therapy for uveal melanoma and retinoblastoma
J William Harbour1, Lori Worley, Duanduan Ma
1Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Campus Box 8069, 660 S Euclid Ave, St Louis, MO 63110, USA. harbour@vision.wustl.edu
Objective:
To determine whether transducible peptides that inhibit the oncoproteins HDM2 and Bcl-2 may selectively kill uveal melanoma and retinoblastoma cells.
Methods:
Peptides were tested by viability assay, flow cytometry, TUNEL (terminal deoxynucleotidyl transferase-mediated fluorescein-dUTP nick-end labeling) assay, Western blot analysis, and reverse transcription-polymerase chain reaction in cultured eye tumor cells and normal cells. Preclinical studies were performed in a rabbit xenograft model of retinoblastoma.
Main Outcome Measures:
Cell survival, apoptosis, gene expression, and tumor regression.
Results:
The anti-Bcl-2 peptide induced apoptosis in tumor cells, but it also caused apoptosis in normal cells in culture and induced retinal damage after intravitreal injection. In contrast, the anti-HDM2 peptide induced rapid accumulation of p53, activation of apoptotic genes, preferential killing of tumor cells, and minimal retinal damage after intravitreal injection. The anti-HDM2 peptide also induced regression of human retinoblastoma cells in rabbit eyes.
Conclusions:
Peptide transduction is a promising new approach to molecular eye cancer therapy. Inhibition of HDM2 can selectively activate p53 in transformed cells and may be an effective strategy for inducing apoptosis in eye cancer cells with minimal damage to normal ocular tissues.
Clinical Relevance:
Molecular characteristics of uveal melanoma and retinoblastoma may be used to design novel therapeutic agents that have greater specificity and fewer adverse effects than current therapies.
Insights
The anti-HDM2 peptide effectively targets and kills eye cancer cells like retinoblastoma by activating p53, offering a promising new therapy with minimal damage to healthy ocular tissues.
Area of Science:
- Ophthalmology
- Oncology
- Molecular Biology
Background:
- Uveal melanoma and retinoblastoma are serious eye cancers.
- Current therapies can cause significant side effects.
- Targeting specific oncoproteins offers a potential for more selective treatment.
Purpose of the Study:
- To evaluate transducible peptides that inhibit HDM2 and Bcl-2 oncoproteins.
- To determine if these peptides can selectively kill uveal melanoma and retinoblastoma cells.
Main Methods:
- Peptides were tested in cultured eye tumor cells and normal cells using viability assays, flow cytometry, TUNEL assays, Western blots, and RT-PCR.
- Preclinical studies utilized a rabbit xenograft model of retinoblastoma.
- Outcomes measured included cell survival, apoptosis, gene expression, and tumor regression.
Main Results:
- The anti-Bcl-2 peptide induced apoptosis in tumor and normal cells, causing retinal damage.
- The anti-HDM2 peptide selectively killed tumor cells by accumulating p53 and activating apoptotic genes, with minimal retinal damage.
- The anti-HDM2 peptide demonstrated regression of retinoblastoma in a rabbit model.
Conclusions:
- Peptide transduction is a promising approach for molecular eye cancer therapy.
- Inhibiting HDM2 selectively activates p53 in transformed cells, inducing apoptosis in eye cancers with minimal ocular tissue damage.
- Tailoring therapeutic agents to the molecular characteristics of uveal melanoma and retinoblastoma can improve specificity and reduce adverse effects.