Alkylation sensitivity screens reveal a conserved cross-species functionome

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Glioblastoma is a highly aggressive brain tumor with limited treatment options.
• Chemotherapy resistance, particularly to temozolomide (TMZ), is a major challenge in glioblastoma treatment.
• Identifying novel therapeutic targets is crucial for improving patient outcomes.

Purpose of the Study:

• To identify genes contributing to chemotherapy resistance in glioblastoma.
• To explore conserved mechanisms of alkylating agent resistance across species.
• To uncover potential new targets for overcoming TMZ resistance.

Main Methods:

• Conducted a synthetic lethal screen using a glioblastoma cell line resistant to TMZ and an siRNA library.
• Validated key DNA repair genes, including uracil-DNA glycosylase (UNG), MYH, and MPG.
• Performed cross-species comparative analysis with E. coli and S. cerevisiae alkylator screens.
• Investigated mechanistic roles of base excision repair (BER) and protein modification systems.

Main Results:

• Confirmed UNG, MYH, and MPG as involved in high-dose TMZ response, potentially via reactive oxygen species.
• Identified a conserved alkylation functionome across human, E. coli, and S. cerevisiae, including novel resistance proteins.
• Dual targeting of BER and protein modification showed additive sensitization in yeast but not in human cells, indicating an epistatic relationship.

Conclusions:

• Discovered novel genes and conserved pathways implicated in glioblastoma TMZ resistance.
• Established UNG and MYH as key players in TMZ response, possibly mediated by oxidative stress.
• Highlighted the potential of targeting conserved DNA repair and protein modification pathways for novel glioblastoma therapies.