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Updated: Aug 9, 2026
Advanced Confocal Microscopy Techniques to Study Protein-protein Interactions and Kinetics at DNA Lesions
Published on: November 12, 2017
High resolution confocal laser scanning microscopy analysis of DNA excision repair capability in small volume marrow
C L Lannon1, L M Ball, A F Pyesmany
1Department of Pathology, Dalhousie University, IWK Grace Health Centre, Halifax, Nova Scotia, Canada.
Background:
Assessment of resistance to drug moieties in tissue culture is complicated by limited sample, clonal selection and alteration of cycling fraction and cycle duration in clonally mixed lesions. DNA damage assessment by single cell gel electrophoresis (SCGE) of excised DNA is limited by non-linear analysis in fluorescent light microscopy. Confocal Laser Scanning Microscopy (CLSM) with high N.A. magnification allows for quantitation of total excised DNA fragment size distribution but is still limited by the large volume required for labour intensive SCGE, precluding multi-exposure clinical testing.
Aims:
To optimise sample requirement for SCGE and CLS.
Methods:
Standard slide mounted bed gels were punched with multiple coded 6 mm wells and filled with suspensions of cells subjected to drug/concentration variations. After SCGE, 30 microns frozen sections were prepared of each well and mounted in ethidium bromide solution on multi-well hydrophilic slides to allow for short working distance of high resolution CLSM in a Zeiss Axiovert L410 SM. Testing for feasibility, reproducibility and consistency used both cultured standard leukaemic cell lines, normal human control marrow and clinical samples.
Results And Conclusion:
Multiple well SCGE followed by frozen section, high resolution CLSM allows for rapid analysis of high numbers of multiple drug exposure permutations clinically required.
Insights
This study optimized single cell gel electrophoresis (SCGE) and Confocal Laser Scanning Microscopy (CLSM) for drug resistance testing. The new method allows rapid analysis of multiple drug exposure permutations in clinical samples.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Assessing drug resistance in tissue culture is challenging due to sample limitations and cellular heterogeneity.
- Traditional DNA damage assessment methods like SCGE are labor-intensive and require large sample volumes.
- Existing techniques limit the feasibility of extensive clinical testing for drug efficacy.
Purpose of the Study:
- To optimize sample requirements for single cell gel electrophoresis (SCGE) and Confocal Laser Scanning Microscopy (CLSM).
- To develop a more efficient method for assessing drug resistance in clinical settings.
Main Methods:
- Developed a multi-well SCGE technique using small sample volumes.
- Integrated SCGE with high-resolution CLSM on frozen sections of multi-well slides.
- Validated the method using leukaemic cell lines, human marrow, and clinical samples.
Main Results:
- The optimized method significantly reduces sample volume requirements for SCGE.
- High-resolution CLSM enabled rapid quantitation of DNA damage.
- The technique demonstrated feasibility, reproducibility, and consistency across various sample types.
Conclusions:
- Multi-well SCGE combined with frozen section CLSM allows for rapid analysis of numerous drug exposure combinations.
- This approach addresses the limitations of previous methods, enabling clinically relevant drug resistance testing.
