Tripartite motif 31 drives gastric cancer cell proliferation and invasion through activating the Wnt/ß-catenin pathway by regulating Axin1 protein stability.

Mounting evidence has proposed the importance of the Wnt/ß-catenin pathway and tripartite motif 31 (TRIM31) in certain malignancies. Our research aimed to clarify the correlation between aberrant TRIM31 expression and the Wnt/ß-catenin pathway during gastric cancer (GC) oncogenesis and development. TRIM31 was drastically elevated in GC tissues and was closely associated with aggressive clinical outcomes and poor prognosis. Moreover, TRIM31 downregulation attenuated GC cell proliferation and invasion in vitro. Mechanistically, TRIM31 could bind and ubiquitinate Axin1 protein, thereby facilitating the activation of the Wnt/ß-catenin pathway. Additionally, Axin1 knockdown partially abrogated the inhibitory effects on the proliferative, invasive and migratory abilities of GC cells induced by TRIM31 silencing. Furthermore, TRIM31 was negatively correlated with Axin1 protein expression in GC tissues. In summary, we revealed a new TRIM31-Axin1-Wnt/ß-catenin axis that contributed greatly to the progression of GC, and targeting this regulatory axis may represent an effective treatment for GC patients.

WWP2 drives the progression of gastric cancer by facilitating the ubiquitination and degradation of LATS1 protein.

BACKGROUND: Large tumor suppressor kinase 1 (LATS1), one of the predominant components of the Hippo pathway, has been characterized as a key player controlling the proliferation and invasion of cancer cells, including gastric cancer (GC) cells. However, the mechanism by which the functional stability of LATS1 is modulated has yet to be elucidated. METHODS: Online prediction tools, immunohistochemistry and western blotting assays were used to explore the expression of WW domain-containing E3 ubiquitin ligase 2 (WWP2) in GC cells and tissues. Gain- and loss-of-function assays, as well as rescue experiments were performed to determine the role of the WWP2-LATS1 axis in cell proliferation and invasion. Additionally, the mechanisms involving WWP2 and LATS1 were assessed by coimmunoprecipitation (Co-IP), immunofluorescence, cycloheximide and in vivo ubiquitination assays. RESULTS: Our results demonstrate a specific interaction between LATS1 and WWP2. WWP2 was markedly upregulated and correlated with disease progression and a poor prognosis in GC patients. Moreover, ectopic WWP2 expression facilitated the proliferation, migration and invasion of GC cells. Mechanistically, WWP2 interacts with LATS1, resulting in its ubiquitination and subsequent degradation, leading to increased transcriptional activity of YAP1. Importantly, LATS1 depletion abolished the suppressive effects of WWP2 knockdown on GC cells. Furthermore, WWP2 silencing attenuated tumor growth by regulating the Hippo-YAP1 pathway in vivo. CONCLUSIONS: Our results define the WWP2-LATS1 axis as a critical regulatory mechanism of the Hippo-YAP1 pathway that promotes GC development and progression. Video Abstract.