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Sugitani N, Moiseeva T, Wang Y, Palmer D, Ford R, Schamus S, Singh A, Lemon K, Kammula U, Vendetti FP, Poholek A, Osmanbeyoglu H, Delgoffe GM, Bakkenist CJ. How do CD8+ T cells complete DNA replication in less than 4 hours? The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.230.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
We demonstrate that activated CD8+ T cells from Pmel mice replicate their genome within 4 hours which is significantly faster than most cancer cells. Many genotoxic chemotherapeutic agents target the rapid proliferation of cancer cells. However, activated T cells also expand rapidly and this can lead to lymphopenia in patients receiving these chemotherapeutic agents. Understanding how CD8+ T cells complete DNA replication in less than 4 hours could lead to the development of treatment schedules that spare CD8+ T cells.
Three possible mechanisms may underlie the rapid DNA replication in CD8+ T cells: 1) faster replication fork velocity, 2) higher density of origin firing, or 3) modified replication timing program, allowing for simultaneous replication of early- and late-replicating regions of the genome. Using DNA combing, we show that the replication fork velocity and inter-origin distance is similar in unperturbed CD8+ T cells and B16 cancer cells. Repli-seq analysis, a NGS genome-wide replication timing analysis, suggest that regions of the genome replicated late in S phase in fibroblasts are replicated earlier in CD8+ T cells, suggesting that the rapid DNA replication in CD8+ T cells is a consequence of a modified, truncated replication timing program. We also show for the first time that actively replicating CD8+ T cells have dormant origins suggesting that this mechanism of genome stability is maintained in activated CD8+ T cells.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Frank P Vendetti
- 3Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | | | | | - Greg M. Delgoffe
- 5Department of Immunology, University of Pittsburgh School of Medicine
| | - Christopher J Bakkenist
- 3Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA
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