SKP2 promotes breast cancer tumorigenesis and radiation tolerance through PDCD4 ubiquitination
SKP2 promotes breast cancer tumorigenesis and radiation tolerance through PDCD4 ubiquitination
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DOI：
10.1186/s13046-019-1069-3
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发表时间：
2019-02-13
影响因子：
11.3
通讯作者：
Wang, Qin
中科院分区：
文献类型：
--
作者：
Li, Ce;Du, Lutao;Wang, Qin
背景：S 期激酶相关蛋白 2 (SKP2) 是一种癌基因和细胞周期调节因子，可特异性识别磷酸化的细胞周期调节蛋白并介导其泛素化。程序性细胞死亡蛋白 4 (PDCD4) 是一种肿瘤抑制基因，通过与真核起始因子 4A (eIF4A) 和 P53 相互作用，在细胞凋亡和 DNA 损伤反应中发挥作用。既往研究表明SKP2可能与PDCD4相互作用，但SKP2和PDCD4之间的关系尚不清楚。方法：为了验证SKP2和PDCD4之间的相互作用，进行了质谱分析和相互免疫共沉淀(Co-IP)实验。建立了SKP2稳定过表达或敲低的乳腺癌细胞系，并使用蛋白质印迹法检测放射前后蛋白质的变化。进行体外和体内实验以验证 SKP2 是否通过抑制 PDCD4 抑制细胞凋亡并促进 DNA 损伤反应。使用SMIP004测试放疗联合SKP2抑制剂的效果。结果：我们发现SKP2显着促进PDCD4磷酸化、泛素化和降解。 SKP2 在乳腺癌中通过抑制 PDCD4 促进细胞增殖、抑制细胞凋亡并增强对 DNA 损伤的反应。 SKP2和PDCD4在人类乳腺癌组织中呈负相关。放疗联合SKP2抑制剂SMIP004在体外和体内对乳腺癌细胞均表现出显着的抑制作用。结论：我们确定PDCD4是SKP2的重要泛素化底物。 SKP2 通过 PDCD4 降解促进乳腺癌肿瘤发生和辐射耐受。在临床医学中，放疗联合SKP2靶向辅助治疗可能会提高乳腺癌患者的生存率。
Background: S-phase kinase-associated protein 2 (SKP2) is an oncogene and cell cycle regulator that specifically recognizes phosphorylated cell cycle regulator proteins and mediates their ubiquitination. Programmed cell death protein 4 (PDCD4) is a tumor suppressor gene that plays a role in cell apoptosis and DNA-damage response via interacting with eukaryotic initiation factor-4A (eIF4A) and P53. Previous research showed SKP2 may interact with PDCD4, however the relationship between SKP2 and PDCD4 is unclear.Methods: To validate the interaction between SKP2 and PDCD4, mass spectrometric analysis and reciprocal co-immunoprecipitation (Co-IP) experiments were performed. SKP2 stably overexpressed or knockdown breast cancer cell lines were established and western blot was used to detect proteins changes before and after radiation. In vitro and in vivo experiments were performed to verify whether SKP2 inhibits cell apoptosis and promotes DNA-damage response via PDCD4 suppression. SMIP004 was used to test the effect of radiotherapy combined with SKP2 inhibitor.Results: We found that SKP2 remarkably promoted PDCD4 phosphorylation, ubiquitination and degradation. SKP2 promoted cell proliferation, inhibited cell apoptosis and enhanced the response to DNA-damage via PDCD4 suppression in breast cancer. SKP2 and PDCD4 showed negative correlation in human breast cancer tissues. Radiotherapy combine with SKP2 inhibitor SMIP004 showed significant inhibitory effects on breast cancer cells in vitro and in vivo.Conclusions: We identify PDCD4 as an important ubiquitination substrate of SKP2. SKP2 promotes breast cancer tumorigenesis and radiation tolerance via PDCD4 degradation. Radiotherapy combine with SKP2-targeted adjuvant therapy may improve breast cancer patient survival in clinical medicine.