The RNA-binding protein La/SSB associates with radiation-induced DNA double-strand breaks in lung cancer cell lines
Related Experiment Video
Updated: Oct 17, 2025
Visualization of DNA Repair Proteins Interaction by Immunofluorescence
Published on: June 26, 2020
Alexander H Staudacher1,2, Yanrui Li1, Vasilios Liapis1
1Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, South Australia, 5000, Australia.
Background:
Platinum-based chemotherapy and radiotherapy are standard treatments for non-small cell lung cancer, which is the commonest, most lethal cancer worldwide. As a marker of treatment-induced cancer cell death, we have developed a radiodiagnostic imaging antibody, which binds to La/SSB. La/SSB is an essential, ubiquitous ribonuclear protein, which is over expressed in cancer and plays a role in resistance to cancer therapies.
Aim:
In this study, we examined radiation-induced DNA double strand breaks (DSB) in lung cancer cell lines and examined whether La/SSB associated with these DSB.
Method:
Three lung cancer lines (A549, H460 and LL2) were irradiated with different X-ray doses or X-radiated with a 5 Gy dose and examined at different time-points post-irradiation for DNA DSB in the form of γ-H2AX and Rad51 foci. Using fluorescence microscopy, we examined whether La/SSB and γ-H2AX co-localise and performed proximity ligation assay (PLA) and co-immunoprecipitation to confirm the interaction of these proteins.
Results:
We found that the radio-resistant A549 cell line compared to the radio-sensitive H460 cell line showed faster resolution of radiation-induced γ-H2AX foci over time. Conversely, we found more co-localised γ-H2AX and La/SSB foci by PLA in irradiated A549 cells.
Conclusion:
The co-localisation of La/SSB with radiation-induced DNA breaks suggests a role of La/SSB in DNA repair, however further experimentation is required to validate this.
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