Direct interaction of β-catenin with nuclear ESM1 supports stemness of metastatic prostate cancer

Wnt/beta-catenin signaling is frequently activated in advanced prostate cancer and contributes to therapy resistance and metastasis. However, activating mutations in the Wnt/beta-catenin pathway are not common in prostate cancer, suggesting alternative regulations may exist. Here, we report that the expression of endothelial cell-specific molecule 1 (ESM1), a secretory proteoglycan, is positively associated with prostate cancer stemness and progression by promoting Wnt/beta-catenin signaling. Elevated ESM1 expression correlates with poor overall survival and metastasis. Accumulation of nuclear ESM1, instead of cytosolic or secretory ESM1, supports prostate cancer stemness by interacting with the ARM domain of beta-catenin to stabilize beta-catenin-TCF4 complex and facilitate the transactivation of Wnt/beta-catenin signaling targets. Accordingly, activated beta-catenin in turn mediates the nuclear entry of ESM1. Our results establish the significance of mislocalized ESM1 in driving metastasis in prostate cancer by coordinating the Wnt/beta-catenin pathway, with implications for its potential use as a diagnostic or prognostic biomarker and as a candidate therapeutic target in prostate cancer.

Automated summary

The study found that ESM1 expression is positively associated with prostate cancer stemness and progression by promoting Wnt/β-catenin signaling activation. Nuclear accumulation of ESM1 supports prostate cancer stemness by interacting with beta-catenin, stabilizing the beta-catenin-TCF4 complex and facilitating the transcription of signaling targets. This highlights the significance of mislocalized ESM1 in driving metastasis in prostate cancer and its potential as a diagnostic or prognostic biomarker and therapeutic target.