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Ex Vivo Culture of Circulating Tumor Cells in the Cerebral Spinal Fluid from Melanoma Patients to Study Melanoma-Associated Leptomeningeal Disease
Published on: March 29, 2024
Functional modulation of IGF-binding protein-3 expression in melanoma
Altaf A Dar1, Shahana Majid, Mehdi Nosrati
1Auerback Melanoma Research Laboratory, Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California, USA.
The Journal of Investigative Dermatology
|April 2, 2010
Summary
Silencing of IGF-binding protein-3 (IGFBP3) in melanoma is caused by promoter methylation. Overexpressing IGFBP3 in melanoma cells suppresses tumor growth, induces apoptosis, and reduces cell survival.
Area of Science:
- Oncology
- Molecular Biology
- Epigenetics
Background:
- IGF-binding protein-3 (IGFBP3) regulates insulin-like growth factor (IGF) effects, including mitogenesis and apoptosis.
- IGFBP3's role in melanoma pathogenesis requires further elucidation.
Purpose of the Study:
- To investigate the role of IGFBP3 in melanoma development and progression.
- To determine the mechanisms underlying IGFBP3 downregulation in melanoma.
- To assess the therapeutic potential of IGFBP3 re-expression in melanoma.
Main Methods:
- Quantitative real-time PCR (qRT-PCR), Western blot, and ELISA to assess IGFBP3 expression.
- Demethylation assays (5-AZA-2'-deoxycytidine) to evaluate promoter activity.
- Chromatin immunoprecipitation (ChIP) assays to analyze histone modifications and DNA methylation.
- In vitro and in vivo studies involving IGFBP3 overexpression in melanoma cells.
Main Results:
- IGFBP3 expression was significantly downregulated in melanoma cell lines and patient samples compared to normal melanocytes and nevi.
- Demethylation treatment restored IGFBP3 expression, indicating epigenetic silencing via promoter methylation.
- IGFBP3 overexpression suppressed melanoma cell survival, colony formation, and invasion, while inducing apoptosis (p21, PUMA, BAX, caspase 3 cleavage).
- IGFBP3 overexpression reduced phosphorylated AKT levels and suppressed tumor growth in vivo.
Conclusions:
- Melanoma progression involves epigenetic silencing of IGFBP3 through promoter methylation.
- Restoring IGFBP3 expression has significant anti-tumor effects, including apoptosis induction and growth suppression.
- IGFBP3 represents a potential therapeutic target for melanoma treatment.
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