The 14-3-3 sigma protein promotes HCC anoikis resistance by inhibiting EGFR degradation and thereby activating the EGFR-dependent ERK1/2 signaling pathway
单位:[1]Hepatic Surgery Center,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology,Clinical Medicine Research Center forHepatic Surgery of Hubei Province,Key Laboratory of Organ Transplantation,Ministry of Education,NHC Key Laboratory of Organ Transplantation,KeyLaboratory of Organ Transplantation,Chinese Academy of Medical Sciences,Wuhan,Hubei 430030,People’s Republic of China华中科技大学同济医学院附属同济医院外科学系肝脏外科器官移植
Resistance to anoikis, cell death due to matrix detachment, is acquired during tumor progression. The 14-3-3 sigma protein is implicated in the development of chemo- and radiation resistance, indicating a poor prognosis in multiple human cancers. However, its function in anoikis resistance and metastasis in hepatocellular carcinoma (HCC) is currently unknown. Methods: Protein expression levels of 14-3-3 sigma were measured in paired HCC and normal tissue samples using western blot and immunohistochemical (IHC) staining. Statistical analysis was performed to evaluate the clinical correlation between 14-3-3 sigma expression, clinicopathological features, and overall survival. Artificial modulation of 14-3-3 sigma (downregulation and overexpression) was performed to explore the role of 14-3-3 sigma in HCC anoikis resistance and tumor metastasis in vitro and in vivo. Association of 14-3-3 sigma with epidermal growth factor receptor (EGFR) was assayed by co-immunoprecipitation. Effects of ectopic 14-3-3 sigma expression or knockdown on EGFR signaling, ligand-induced EGFR degradation and ubiquitination were examined using immunoblotting and co-immunoprecipitation, immunofluorescence staining, and flow cytometry analysis. The levels of EGFR ubiquitination, the interaction between EGFR and 14-3-3 sigma, and the association of EGFR with c-Cbl after EGF stimulation, in 14-3-3 sigma overexpressing or knockdown cells were examined to elucidate the mechanism by which 14-3-3 sigma inhibits EGFR degradation. Using gain-of-function or loss-of-function strategies, we further investigated the role of the EGFR signaling pathway and its downstream target machinery in 14-3-3 sigma-mediated anoikis resistance of HCC cells. Results: We demonstrated that 14-3-3 sigma was upregulated in HCC tissues, whereby its overexpression was correlated with aggressive clinicopathological features and a poor prognosis. In vitro and in vivo experiments indicated that 14-3-3 sigma promoted anoikis resistance and metastasis of HCC cells. Mechanistically, we show that 14-3-3 sigma can interact with EGFR and significantly inhibit EGF-induced degradation of EGFR, stabilizing the activated receptor, and therefore prolong the activation of EGFR signaling. We demonstrated that 14-3-3 sigma downregulated ligand-induced EGFR degradation by inhibiting EGFR-c-Cbl association and subsequent c-Cbl-mediated EGFR ubiquitination. We further verified that activation of the ERK1/2 pathway was responsible for 14-3-3 sigma-mediated anoikis resistance of HCC cells. Moreover, EGFR inactivation could reverse the 14-3-3 sigma-mediated effects on ERK1/2 phosphorylation and anoikis resistance. Expression of 14-3-3 sigma and EGFR were found to be positively correlated in human HCC tissues. Conclusions: Our results indicate that 14-3-3 sigma plays a pivotal role in the anoikis resistance and metastasis of HCC cells, presumably by inhibiting EGFR degradation and regulating the activation of the EGFR-dependent ERK1/2 pathway. To our best knowledge, this is the first report of the role of 14-3-3 sigma in the anoikis resistance of HCC cells, offering new research directions for the treatment of metastatic cancer by targeting 14-3-3 sigma.
基金:
the National Natural Science Foundation of China (No.
81372327, No. 81572427 to Bixiang Zhang; No.
81202300 to Huifang Liang)
第一作者单位:[1]Hepatic Surgery Center,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology,Clinical Medicine Research Center forHepatic Surgery of Hubei Province,Key Laboratory of Organ Transplantation,Ministry of Education,NHC Key Laboratory of Organ Transplantation,KeyLaboratory of Organ Transplantation,Chinese Academy of Medical Sciences,Wuhan,Hubei 430030,People’s Republic of China
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推荐引用方式(GB/T 7714):
Song Jia,Liu Yachong,Liu Furong,et al.The 14-3-3 sigma protein promotes HCC anoikis resistance by inhibiting EGFR degradation and thereby activating the EGFR-dependent ERK1/2 signaling pathway[J].THERANOSTICS.2021,11(3):996-1015.doi:10.7150/thno.51646.
APA:
Song,Jia,Liu, Yachong,Liu,Furong,Zhang,Lu,Li, Ganxun...&Zhang,Bixiang.(2021).The 14-3-3 sigma protein promotes HCC anoikis resistance by inhibiting EGFR degradation and thereby activating the EGFR-dependent ERK1/2 signaling pathway.THERANOSTICS,11,(3)
MLA:
Song,Jia,et al."The 14-3-3 sigma protein promotes HCC anoikis resistance by inhibiting EGFR degradation and thereby activating the EGFR-dependent ERK1/2 signaling pathway".THERANOSTICS 11..3(2021):996-1015