SDCBP is an adapter protein containing two tandem PDZ domains mediating cell adhesion. The role and underlying molecular mechanism of SDCBP in ESCC remain obscure. Here, we report that SDCBP is frequently overexpressed in ESCC tissues and cells compared to normal controls and that its overexpression is correlated with late clinical stage and predicts poor prognosis in ESCC patients. Functionally, high expression of SDCBP is positively related to ESCC progression both in vitro and in vivo. Furthermore, mechanistic studies show that SDCBP activates the EGFR-PI3K-Akt signaling pathway by binding to EGFR and preventing EGFR internalization. Moreover, we provide evidence that AURKA binds to SDCBP and phosphorylates it at the Ser131 and Thr200 sites to inhibit ubiquitination-mediated SDCBP degradation. More importantly, the sites at which AURKA phosphorylates SDCBP are crucial for the EGFR signaling-mediated oncogenic function of SDCBP. Taken together, we propose that SDCBP phosphorylation by AURKA prevents SDCBP degradation and promotes ESCC tumor growth through the EGFR-PI3K-Akt signaling pathway. Our findings unveil a new AURKA–SDCBP–EGFR axis that is involved in ESCC progression and provide a promising therapeutic target for ESCC treatment in the clinic.
Bibliographical noteFunding Information:
Acknowledgements This study was supported by the National Natural Science Foundation of China (Nos. 81802795 and 31301144); the Key Scientific Research Project Plan of Colleges and Universities in Henan Province (No. 18A310034); the Science and Technology Project of Henan Province (Nos. 182102310324 and 202102310206); and the Training plan for Young Backbone Teachers of Zhengzhou University (No. 2018ZDGGJS037).
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- Research Support, Non-U.S. Gov't