期刊
CELL CYCLE
卷 8, 期 1, 页码 66-75出版社
TAYLOR & FRANCIS INC
DOI: 10.4161/cc.8.1.7451
关键词
speedy/ringo; DNA damage; cyclin; repair; tumorigenesis; mutagenesis; p53
类别
资金
- Achievement Rewards for College Scientists (ARCS) Foundation
- Ruth L. Kirschstein National Research Service Award (NIH/NCI) [T32 CA009523]
- Randy Gastwirt and the California Breast Cancer Research [14IB-0065]
- NATIONAL CANCER INSTITUTE [T32CA009523] Funding Source: NIH RePORTER
The intrinsic damage response is activated by DNA damage that arises during the cell division process. The ability of the cell to repair this damage during proliferation is important for normal cell growth and, when disrupted, may lead to increased mutatagenesis and tumorigenesis. The atypical CDK activator, Spy1, was previously shown to promote cell survival, prevent apoptosis and inhibit checkpoint activation in response to DNA damage. Prior studies have shown that Spy1 is upregulated in breast carcinomas and accelerates mammary tumorigenesis in vivo. In this report, first, we demonstrate that the ability of Spy1 to inhibit apoptosis and bypass UV-induced checkpoint activation is dependent on the presence of the gene regulatory protein p53 and the CKI p21. Second, we demonstrate that Spy1 expression has the following effects: prevents repair of cyclobutane pyrimidine dimers through bypass of nucleotide excision repair; increases the cellular mutation frequency; and reduces the formation of cyclin E induced gamma H2A.X foci. Lastly, we show that knockdown of endogenous Spy1 leads to gamma H2A.X foci formation, Chk1 phosphorylation and proliferation defects, demonstrating a functional role for Spy1 in the intrinsic DNA damage response. These results also demonstrate that Spy1 fulfills a novel regulatory role in the intrinsic DNA damage response and maintains the balance between checkpoint activation, apoptosis, repair and cell cycle progression in response to exogenous or intrinsic damage. Furthermore, the overexpression of Spy1 as a contributing factor in cancer progression will most likely be confined to p53-positive cells.
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