Cyclin G2 suppresses Wnt/β-catenin signaling and inhibits gastric cancer cell growth and migration through Dapper1

Abstract

BackgroundGastric cancer is one of the most common malignant tumors. Cyclin G2 has been shown to be associated with the development of multiple types of tumors, but its underlying mechanisms in gastric tumors is not well-understood. The aim of this study is to investigate the role and the underlying mechanisms of cyclin G2 on Wnt/β-catenin signaling in gastric cancer.MethodsReal-time PCR, immunohistochemistry and in silico assay were used to determine the expression of cyclin G2 in gastric cancer. TCGA datasets were used to evaluate the association between cyclin G2 expression and the prognostic landscape of gastric cancers. The effects of ectopic and endogenous cyclin G2 on the proliferation and migration of gastric cancer cells were assessed using the MTS assay, colony formation assay, cell cycle assay, wound healing assay and transwell assay. Moreover, a xenograft model and a metastasis model of nude mice was used to determine the influence of cyclin G2 on gastric tumor growth and migration in vivo. The effects of cyclin G2 expression on Wnt/β-catenin signaling were explored using a TOPFlash luciferase reporter assay, and the molecular mechanisms involved were investigated using immunoblots assay, yeast two-hybrid screening, immunoprecipitation and Duolink in situ PLA. Ccng2−/− mice were generated to further confirm the inhibitory effect of cyclin G2 on Wnt/β-catenin signaling in vivo. Furthermore, GSK-3β inhibitors were utilized to explore the role of Wnt/β-catenin signaling in the suppression effect of cyclin G2 on gastric cancer cell proliferation and migration.ResultsWe found that cyclin G2 levels were decreased in gastric cancer tissues and were associated with tumor size, migration and poor differentiation status. Moreover, overexpression of cyclin G2 attenuated tumor growth and metastasis both in vitro and in vivo. Dpr1 was identified as a cyclin G2-interacting protein which was required for the cyclin G2-mediated inhibition of β-catenin expression. Mechanically, cyclin G2 impacted the activity of CKI to phosphorylate Dpr1, which has been proved to be a protein that acts as a suppressor of Wnt/β-catenin signaling when unphosphorylated. Furthermore, GSK-3β inhibitors abolished the cyclin G2-induced suppression of cell proliferation and migration.ConclusionsThis study demonstrates that cyclin G2 suppresses Wnt/β-catenin signaling and inhibits gastric cancer cell growth and migration through Dapper1.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0973-2) contains supplementary material, which is available to authorized users.

Cyclin G2 regulates canonical Wnt signalling via interaction with Dapper1 to attenuate tubulointerstitial fibrosis in diabetic nephropathy

“…To explore the mechanisms by which cyclin G2 regulates Wnt signalling, we conducted yeast two‐hybrid experiments and screened cyclin G2‐conjugated proteins, which identified Dpr1, a Dvl binding antagonist protein . Coimmunoprecipitation and Duolink in situ proximity ligation assays (PLA) were used to confirm that Dpr1 interacted with cyclin G2 in HK‐2 cells (Figure A,B).…”

“…Three independent experiments were performed gastric cancer cell growth and migration. 45 Furthermore, cyclin G2 also inhibits the epithelial-to-mesenchymal transition by disrupting Wnt/β-catenin signalling in epithelial ovarian cancer. 55 CK1 has been shown to phosphorylate Dpr1 and impede the interaction of Dpr1 with Dvl2, which results in the activation of Wnt signalling.…”

“…To explore the mechanisms by which cyclin G2 regulates Wnt signalling, we conducted yeast two-hybrid experiments and screened cyclin G2-conjugated proteins, which identified Dpr1, a Dvl binding antagonist protein. 45 Coimmunoprecipitation and Duolink in situ F I G U R E 2 A deficiency in cyclin G2 increased proteinuria in a DN mouse model. A-E, Ccng2 −/− and WT mice were treated with citrate buffer or STZ.…”

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Long noncoding RNA OIP5‐AS1 aggravates cell proliferation, migration in gastric cancer by epigenetically silencing NLRP6 expression via binding EZH2

“…1,2 What is worse, most patients are diagnosed as GC at an advanced stage, which unfortunately is accompanied by poor prognosis. 1,2 What is worse, most patients are diagnosed as GC at an advanced stage, which unfortunately is accompanied by poor prognosis.…”