WBP2 Negatively Regulates Hippo Pathway By Competitively Binding To WWC3 With LATS1 To Promote The Malignant Phenotype Of Non-Small Cell Lung Cancer

Abstract

Background: WW domain binding protein-2 (WBP2) can function as a YAP/TAZ co-activator and play a vital role in promoting breast cancer progression. However, the expression and potential molecular mechanism of WBP2 in the context of lung cancer are not fully understood. Methods: Expression and subcellular localization of WBP2 in clinical samples and in lung cancer cell lines were analyzed with respect to various clinical pathological parameters using Chi-square tests. We used a series of cell function experiments and tumor formation experiments in nude mice to verify the effect of WBP2 on tumor cell proliferation and invasion. Dual-directional regulation of WBP2 expression, immunoprecipitation, luciferase reporter assays, and quantitative PCR analyses were used to explore the regulatory mechanisms and identify associated molecular markers.Results: We determined that WBP2 was highly expressed in lung cancer specimens and cell lines and that this expression was closely related to the pTNM stage, lymph node metastasis, and poor prognosis of patients. Additionally, gain and loss of function experiments revealed that WBP2 could significantly promote the proliferation and invasion of lung cancer cells both in vivo and in vitro. To elucidate the underlying molecular mechanism, we determined that wild-type WBP2 could competitively bind to the WW domain of WWC3 with LATS1 through its PPxY motifs to inhibit the formation of the WWC3-LATS1 complex, reduce the phosphorylation level of LATS1, and ultimately promote YAP nuclear translocation to suppress the activity of the Hippo pathway. Conclusions: From the aspect of upstream molecules of Hippo signaling, WBP2 promotes the malignant phenotype of lung cancer cells in a unique manner that is not directly dependent upon YAP, thus providing a corresponding experimental basis for the development of targeted therapeutic drugs for lung cancer.