Histone demethylase KDM2A is a selective vulnerability of cancers relying on alternative telomere maintenance

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Telomere length maintenance is crucial for cellular immortalization and cancer development.
• Alternative lengthening of telomeres (ALT) is a recombination-based mechanism used by 5-10% of human cancers for telomere maintenance.
• Targeted therapies for ALT-dependent cancers are currently lacking.

Purpose of the Study:

• To identify molecular vulnerabilities in ALT-dependent cancer cells.
• To investigate the role of histone lysine demethylase KDM2A in ALT-mediated telomere maintenance.
• To explore KDM2A as a potential therapeutic target for ALT cancers.

Main Methods:

• CRISPR/Cas9-based genetic screens in an ALT-immortalized cellular model.
• Mechanistic studies on KDM2A's role in telomere cluster dissolution.
• Analysis of SENP6-mediated SUMO deconjugation at telomeres.
• Assessment of chromosome segregation and mitotic cell death upon KDM2A or SENP6 inactivation.

Main Results:

• KDM2A was identified as a selective vulnerability in ALT-dependent cancer cells.
• KDM2A is essential for the dissolution of ALT-specific telomere clusters post-recombination.
• KDM2A facilitates SENP6-mediated SUMO deconjugation at telomeres, crucial for de-clustering.
• Inactivation of KDM2A or SENP6 leads to impaired telomere de-SUMOylation, chromosome missegregation, and mitotic cell death.

Conclusions:

• KDM2A is a critical factor for ALT telomere maintenance by promoting telomere cluster dissolution.
• KDM2A represents a selective molecular vulnerability and a promising therapeutic target for ALT-dependent cancers.