Lin Youcheng, Yang Zhao, Xu Abai, Dong Pei, Huang Yi, Liu Huan, Li Feida, Wang Haifeng, Xu Qian, Wang Yongqiang, Sun Da, Zou Yong, Zou Xiaowen, Wang Yu, Zhang Duo, Liu Hongjie, Wu Xun, Zhang Meng, Fu Yu, Cai Zhiming, Liu Chunxiao, Wu Song
Department of Urology, Zhujiang Hospital of Southern Medical University, Guangzhou 510280, China.
1] CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China [2] University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Rep. 2015 Mar 11;5:8997. doi: 10.1038/srep08997.
The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway has been identified as an important pathway in renal cell carcinoma (RCC). We have reported a nonsense mutation in PIK3R1, which encodes the regulatory subunit of PI3K, in a metastatic RCC (mRCC), while the mutation was absent in the corresponding primary RCC (pRCC). To identify the function of PIK3R1 in RCC, we examined its expression in normal kidney, pRCC and mRCC by immunohistochemistry and real-time polymerase chain reaction. The expression of PIK3R1 significantly decreased in pRCC and was further reduced in mRCC compared with normal tissue. Besides, its expression levels were negatively correlated with T-category of tumor stage. Additionally, 786-O and A-704 cells with PIK3R1 depletion introduced by CRISPR/Cas9 system displayed enhanced proliferation, migration and epithelial-mesenchymal transition (EMT), and acquired a stem-like phenotype. Moreover, the PIK3R1 depletion promoted the phosphorylation of AKT in the cells. The knockdown of AKT by shRNA reduced p-GSK3β and CTNNB1 expression in the cells, while the depletion of CTNNB1 impaired stem-like phenotype of the cells. Overall, PIK3R1 down-regulation in RCC promotes propagation, migration, EMT and stem-like phenotype in renal cancer cells through the AKT/GSK3β/CTNNB1 pathway, and may contribute to progression and metastasis of RCC.
磷酸肌醇3激酶（PI3K）/蛋白激酶B（AKT）信号通路已被确定为肾细胞癌（RCC）中的一条重要信号通路。我们报道了在一例转移性肾细胞癌（mRCC）中PIK3R1（编码PI3K的调节亚基）存在无义突变，而在相应的原发性肾细胞癌（pRCC）中未发现该突变。为了确定PIK3R1在肾细胞癌中的功能，我们通过免疫组织化学和实时聚合酶链反应检测了其在正常肾脏、pRCC和mRCC中的表达。与正常组织相比，PIK3R1在pRCC中的表达显著降低，在mRCC中进一步降低。此外，其表达水平与肿瘤分期的T类别呈负相关。此外，通过CRISPR/Cas9系统敲低PIK3R1的786-O和A-704细胞表现出增殖、迁移和上皮-间质转化（EMT）增强，并获得了干细胞样表型。此外，PIK3R1的缺失促进了细胞中AKT的磷酸化。用shRNA敲低AKT可降低细胞中p-GSK3β和CTNNB1的表达，而敲低CTNNB1则损害细胞的干细胞样表型。总体而言，肾细胞癌中PIK3R1的下调通过AKT/GSK3β/CTNNB1信号通路促进肾癌细胞的增殖、迁移、EMT和干细胞样表型，可能有助于肾细胞癌的进展和转移。
