| Background and purpose:WWP2 is a member of the HECT–domain–containing E3 ubiquitin ligase family,which can specifically bind to its substrates and promote its substrates to be ubiquitinated and degraded.Several recent studies have shown that WWP2 expression is aberrantly elevated in multiple cancers,including glioblastoma,lung cancer,hepatocellular carcinoma,oral tumors and et al.High expression of WWP2 exerts its crucial role in promoting tumorigenesis and progression through different regulatory mechanisms.In this study,we investigated the expression of WWP2 in GC cell lines and tissues,and in-depth studied the underlying mechanism by which WWP2 promoting GC cell proliferation,invasion and metastasis.Methods:Co-Immunoprecipitation(Co-IP)and immunofluorescence staining(IF)were used to identify whether WWP2 was a novel binding partner of LATS1 protein,which is a component of the Hippo signaling pathway.Immunohistochemical staining experiments(IHC)and related bioinformatical tools website were utilized to analyze the expression of WWP2 in GC tissues,and further explored the correlation between its protein expression with the clinicopathological characteristics and prognosis of GC patients.Western blotting assays were performed to detect the expression of WWP2 in GC cell lines and clinical tissues.The biological functional experiments were used to verify the effects of WWP2 on the proliferation,migration and invasion of GC cells.Western blotting and quantitative real-time PCR assays were used to study the relationship between the expression of WWP2 with the Hippo-YAP pathway.The protein half-life experiment(CHX),ubiquitination experiment and reversal experiment were used to explore the underlying mechanism by which WWP2 suppressed the expression of LAST1,thus leading the dysregulation of the Hippo-YAP signaling pathway.The nude mice model was used to verified the impact and mechanism of WWP2 on the growth ability of GC cells in vivo.Results:WWP2 can interact with LATS1.Bioinformatical analysis showed that WWP2 is abnormally expressed in a variety of human tumors,including GC.The IHC analysis suggested that the high expression of WWP2 was closely related to the poor clinical stage,metastasis and poor prognosis of patients with GC.WWP2 expression was frequentyly upregulated in gastric cancer cells.Overexpression of WWP2 obviously accelerated the proliferation,colony formation and invasion ability of gastric cancer cells,and knockdown of WWP2 exerted the opposite effects.Molecular mechanim analysis showed that WWP2 as a negative regulator of LATS1 protein to induce the transcription of downstream target genes of the Hippo pathway,such as CTGF and CYR61.The reversal experiments found the cancer-promoting effects of WWP2 on GC cell growth,migration,and invasion are partially mediated by LATS1.Furthermore,WWP2 depletion weakened its carcinogenic abilities in a nude mouse model.Conclusion:WWP2 was upregulated in GC,and its overexpression was significantly correlated with disease progression and poor prognosis in patients with GC.WWP2 stimulates gastric cancer tumorigenesis and progression by regulating the Hippo-YAP signaling pathwayvia promoting LATS1 protein ubiquitination and degradation.Our data for the first time uncovered that the WWP2-LATS1-YAP signal axis was very important in the progression and tumorigenesis of gastric cancer and furnish a novel therapeutic target for gastric cancer patients. |
