Telomere-based DNA damage responses: a new approach to melanoma

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Melanoma is a deadly skin cancer with high chemotherapy resistance.
• Telomeres are critical DNA sequences at chromosome ends, and their 3' overhang is a target for therapeutic intervention.

Purpose of the Study:

• To investigate the efficacy of T-oligo, a DNA oligonucleotide mimicking telomere sequences, as a potential melanoma treatment.
• To determine the selectivity of T-oligo for melanoma cells versus normal melanocytes.
• To evaluate the in vivo therapeutic effects of T-oligo on melanoma tumor growth and metastasis.

Main Methods:

• Treatment of human melanoma cell lines and normal melanocytes with T-oligo in vitro.
• Xenograft mouse models (SCID mice) with human melanoma cells (MM-AN) were used to assess in vivo efficacy.
• T-oligo was administered via injection (intralesional or systemic) to established tumors.
• Analysis of apoptosis, cell cycle arrest, tumor volume, metastasis, and protein expression (livin/ML-IAP).

Main Results:

• T-oligo induced apoptosis in multiple melanoma cell lines, including aggressive MM-AN.
• Normal melanocytes showed only transient cell cycle arrest, indicating selective toxicity towards malignant cells.
• In vivo, T-oligo treatment reduced melanoma tumor volume by 85-95% and metastasis by 85-90%.
• Established tumors were significantly inhibited by T-oligo with no detectable toxicity.
• Down-regulation of the inhibitor of apoptosis protein livin/ML-IAP was observed.

Conclusions:

• T-oligo selectively targets and induces apoptosis in melanoma cells.
• T-oligo demonstrates significant anti-tumor and anti-metastatic activity in vivo without toxicity.
• T-oligo may function by mimicking DNA damage, activating cancer prevention pathways.
• T-oligos represent a novel therapeutic candidate for melanoma treatment.