Quantifying Replication Stress in Ovarian Cancer Cells Using Single-Stranded DNA Immunofluorescence

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• Replication stress is a key feature in various ovarian cancers, often leading to single-stranded DNA (ssDNA) generation.
• Quantifying ssDNA offers a method to evaluate replication stress levels across different cell types and in response to DNA-damaging agents.
• ssDNA levels may predict patient responses to DNA repair-targeting chemotherapies.

Purpose of the Study:

• To present a detailed immunofluorescence-based method for quantifying ssDNA.
• To establish a reproducible and rapid technique for assessing replication stress.
• To enable high-throughput screening for drug discovery and genetic studies.

Main Methods:

• Genome labeling with a thymidine analog.
• Antibody-based detection of the analog on chromatin under non-denaturing conditions.
• Visualization and quantification of ssDNA foci using fluorescence microscopy and an automated pipeline.

Main Results:

• ssDNA is visualized as nuclear foci, with their number and intensity correlating directly with ssDNA levels.
• The described immunofluorescence method is rapid, reproducible, and simple to implement.
• The methodology is suitable for high-throughput applications, including drug and genetic screens.

Conclusions:

• This immunofluorescence technique provides a reliable way to quantify ssDNA, serving as a biomarker for replication stress.
• The method's simplicity and speed make it valuable for both basic research and clinical applications, particularly in ovarian cancer.
• ssDNA quantification can guide personalized treatment strategies by predicting responses to specific chemotherapies.