WWP1 upregulation predicts poor prognosis and promotes tumor progression by regulating ubiquitination of NDFIP1 in intrahepatic cholangiocarcinoma

Abstract

WW domain-containing E3 ubiquitin protein ligase1 (WWP1) is reported to be upregulated in many types of human cancers; however, its expression and function in intrahepatic cholangiocarcinoma (ICC) remain unknown. Here, in this study we investigated the expression pattern, clinical prognosis, tumor biological functions, and molecular mechanisms of WWP1 in ICC. The expression of WWP1 in patient tissues was detected by western blotting, immunohistochemistry (IHC), and immunofluorescence. CCK-8, colony formation, EdU, transwell, and xenograft models were used to explore the role of WWP1 in the proliferation and metastasis of ICC. Co-immunoprecipitation, mass spectrometry, chromatin immunoprecipitation, and immunofluorescence were performed to detect the potential mechanisms. Our study revealed that WWP1 was highly expressed in ICC, and high levels of WWP1 were associated with poor prognosis. Functionally, WWP1 overexpression enhanced the proliferation and metastasis of ICC cells and vice versa. Mechanistically, MYC could be enriched in the promoter region of WWP1 to facilitate its expression. Then, WWP1 targets Nedd4 family interacting protein1 (NDFIP1) and reduces NDFIP1 protein levels via ubiquitination. Downregulation of NDFIP1 in ICC cells rescued the effects of silenced WWP1 expression. WWP1 expression was also negatively correlated with the protein level of NDFIP1 in patient tissues. In conclusion, WWP1 upregulated by MYC promotes the progression of ICC via ubiquitination of NDFIP1, which reveals that WWP1 might be a potential therapeutic target for ICC.

WWP1 localizes in the Golgi apparatus and contributes to maintaining glycosaminoglycan synthesis in adipocytes

“…Previous studies have identi ed NDFIP1 (Nedd4 family interacting protein 1; also known as N4WBP5) as a novel interacting protein of NEDD4 family proteins (such as WWP1, WWP2 and NEDD4) with their WW domains via PPXY motifs [22,23]. Harvey et al demonstrated that NDFIP1 is co-localized with the Golgi matrix protein GM130, and the ectopic expression of NDFIP1 causes disruption of GM130 staining in baby hamster kidney cells; these ndings suggest that NDFIP1 is involved in Golgi apparatus structure [22].…”

Molecular mechanism of WWP1‐mediated ubiquitination modification affecting proliferation and invasion/migration of liver cancer cells

“…For example, WWP1 overexpression predicts unfavorable prognoses and fastens ICC progression by mediating NDFIP1 ubiquitination. 13 WWP1 deficiency suppresses HCC cell growth and causes apoptosis by activating caspase3 and p53. 14 WWP1 depletion can activate TRAIL-induced caspase-8 recruitment and apoptosis, as well as suppress ERα-positive breast cancer cell survival.…”

“…The WWP1 mRNA and protein levels are mostly up‐regulated in a subset of human malignancies. For example, WWP1 overexpression predicts unfavorable prognoses and fastens ICC progression by mediating NDFIP1 ubiquitination 13 . WWP1 deficiency suppresses HCC cell growth and causes apoptosis by activating caspase3 and p53 14 .…”

“…WW domain‐containing E3 ubiquitin protein ligase 1 (WWP1) is a versatile E3 ubiquitin ligase involved in diverse biological processes including cell proliferation, protein trafficking and transcription, and epithelial sodium channel regulation 10 . WWP1 is commonly overexpressed and genetically amplified in human malignancies including colorectal cancer, 11 breast cancer, 12 and ICC 13 . WWP1 has high expression profiles in HCC, and WWP1 knockdown represses growth but induces apoptosis of HCC cells by activating caspase3 and p53 14 .…”

“…10 WWP1 is commonly overexpressed and genetically amplified in human malignancies including colorectal cancer, 11 breast cancer, 12 and ICC. 13 WWP1 has high expression profiles in HCC, and WWP1 knockdown represses growth but induces apoptosis of HCC cells by activating caspase3 and p53. 14 WWP1 overexpression accelerates HCC tumorigenesis and predicts dismal outcomes, representing an attractive molecular target for HCC treatment.…”