端粒长度和功能的维持是保持癌症细胞的增殖能力的重要机制之一。癌症细胞利用端粒酶或者同源重组机制有效抵抗端粒的缩短，但癌症细胞如何在DNA损伤时，特别在双链损伤时，有抗衡DNA损伤，维持端粒稳态并不清楚。我们通过质谱分析发现，CDK2能聚集到端粒的位置，且倾向于同源重组活跃的骨肉瘤USO2癌细胞中。在诱导端粒双链损伤的后，CDK2的聚集增强。在给与CDK2抑制剂后，我们能明显地观察到在细胞周期S期，端粒和染色体产生不利于同源重组的压缩结构。通过磷酸化预测，我们发现TRF1 S11是潜在的CDK2磷酸化位点，在突变体TRF1 S11A表达的细胞中，我们观察得了端粒DNA损伤的显著增加，且端粒和细胞核结构紧缩，类似于CDK2抑制剂的效应。因此，我们推测，在细胞周期和DNA损伤时，存在CDK2-TRF1通路为主导的，调控癌细胞端粒的同源重组，维持端粒的长度和稳态的一种新机制。

Cancer cells preserve the capability of unlimited growth by maintaining telomere length. It employs the telomerase or mechanism of homologous recombination(HR) to efficiently counteract the telomeres shortening. However, how cancer cell maintain the telomere stability under DNA damage, especially double strand breaks, are still poorly understood. In this study, we find CDK2 preferentially interacts with TRF1 in HR active U2OS compared HeLa cell. The recruitment of CDK2 is greatly increased at damaged telomere after TRF1-Fok1 induced double strand breaks. By treating the cells with CDK2 inhibitors, we find the compacted structure of telomeres and nuclears, which may exert inhibition for HR. More importantly, we predict the potential CDK2 substrate TRF1 S11 site which is largely detected in cancer cell line in mass spectrometry analysis. The cells expressing TRF1 S11A exhibit the higher percentage of DNA damage foci at telomere compared the TRF1 S11D. Intriguingly, TRF1 S11A shows the compacted telomere structure that is reminiscent of cells with CDK2 inhibitor. Thus, we hypothesize that CDK2 regulates homologous recombination in cancer cells through phosphorylation of TRF S11.