WWP1 inhibition suppresses the proliferation of pancreatic cancer cells by regulating the PI3K-AKT pathway.

Abstract

The proto-oncogene WWP1 is overexpressed in various cancers and contributes to tumor growth and poor prognosis. Recently, WWP1 inhibition was reported to suppress tumor development and cell proliferation by activating the PTEN function. However, the expression profiles and clinical significance of WWP1 in pancreatic ductal adenocarcinoma (PDAC) tissues remain undetermined. Therefore, this study aimed to evaluate the WWP1 expression in PDAC and investigate the therapeutic potential of WWP1 inhibition. Cellular proliferation assays were performed using a doxycycline-inducible shWWP1 expression system. Transcriptome analyses were conducted to identify the altered pathways in WWP1-depleted cells. PTEN ubiquitination by WWP1 was confirmed using immunoprecipitation assays. In vivo xenograft and drug screening assays were performed to evaluate the clinical significance of WWP1 inhibition. WWP1 was significantly upregulated in PDAC tissues and associated with poor prognosis. WWP1 depletion significantly reduced the proliferation of PDAC cell lines, correlating with the suppression of the PI3K-AKT pathway. Mechanistically, as reported in other cancer types, PTEN is a target of WWP1 in PDAC cells. PTEN silencing abrogated the growth-inhibitory effects in WWP1-depleted cells, suggesting that the anti-tumor effects of WWP1 inhibition are mediated through PTEN activation. In vivo xenograft studies confirmed that WWP1 depletion substantially inhibited tumor growth. Moreover, drug screening assays revealed that WWP1 depletion had an additive effect with the PI3K-AKT pathway inhibitors on hindering tumor growth. WWP1 inhibition enhances the anti-tumor effects of PI3K-AKT pathway inhibitors through PTEN activation. Thus, WWP1 could be a potential therapeutic target in PDAC.