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PCNA/cyclin expression and BrdU uptake define different subpopulations in different cell lines.
1Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle 98195.
Summary
Monoclonal antibodies to proliferating cell nuclear antigen (PCNA/cyclin) identify proliferating cells, but their distribution varies by cell type. PCNA/cyclin expression differs from BrdU incorporation and Ki-67 in various cell lines, impacting studies of mixed cell populations.
Area of Science:
- Cell Biology
- Immunohistochemistry
- Cancer Research
Background:
- Monoclonal antibodies (MAb) to proliferating cell nuclear antigen (PCNA/cyclin) are used to identify proliferating cells in vitro and in fixed tissues.
- Routine use of anti-PCNA/cyclin MAb necessitates understanding PCNA/cyclin distribution across diverse cell populations.
- Investigative and diagnostic pathology relies on accurate identification of cell proliferation markers.
Purpose of the Study:
- To compare the ability of MAb to PCNA/cyclin, Ki-67, and 5'-bromodeoxyuridine (BrdU) in identifying proliferating cells across different cell lines.
- To investigate the distribution patterns of PCNA/cyclin expression relative to BrdU incorporation and Ki-67 in various cell types.
- To assess the implications of these marker distributions for studying mixed cell populations.
Main Methods:
- Utilized MAb 19A2 (PCNA/cyclin), Ki-67, and BU-1 (BrdU) for immunofluorescence studies.
- Employed four cell lines with varying proliferation rates and lineages: HeLa, A-431 (malignant carcinoma), SK-5 (non-transformed fibroblast), and HUVE (non-transformed endothelial).
- Performed single and double labeling after a 1-hour incubation with BrdU.
Main Results:
- Substantial qualitative and quantitative differences were observed in PCNA/cyclin expression and BrdU incorporation across cell lines.
- In HeLa and A-431 cells, BrdU staining was a subset of PCNA-positive cells; in HUVE cells, overlap was incomplete; in SK-5 cells, populations were mutually exclusive.
- MAb Ki-67 showed a pattern predictive of PCNA positivity only in the SK-5 cell line.
Conclusions:
- PCNA/cyclin expression detected by MAb may identify different cell subpopulations depending on the cell type, relative to BrdU incorporation or Ki-67.
- The distinct expression patterns of proliferation markers highlight the need for careful interpretation in heterogeneous cell populations.
- Findings have significant implications for the clinical study and diagnostic application of these antibodies in mixed cell environments.