SPOCK1 activates Wnt/ß-Catenin signaling to drive colorectal cancer stemness and progression
Colorectal cancer (CRC) ranks second in cancer-related mortality worldwide, with clinical intractability and chemoresistance representing significant challenges driven by cancer stem cells (CSCs). Wnt/ß-catenin signaling is a lynchpin of CSC self-renewal, but targetable upstream drivers remain elusive. Using bioinformatics we identified the proteoglycan SPOCK1 as a Wnt-associated CSC target. Critically, high SPOCK1 expression predicted poor patient prognosis and reduced progression-free survival following first-line chemotherapy. In vitro assays demonstrated that SPOCK1 levels modulated Wnt/ß-catenin activity. SPOCK1 silencing inhibited ß-catenin nuclear translocation and TCF/LEF-mediated transcription, which concurrently suppressed CRC proliferation and stemness. Conversely, SPOCK1 overexpression promoted ß-catenin nuclear translocation and TCF/LEF-mediated transcription, which enhanced CRC proliferation and stemness. This SPOCK1-driven pro-tumorigenic effect was significantly reversed by the ß-catenin/TCF/LEF inhibitor iCRT3, demonstrating SPOCK1's dependence on Wnt transcriptional activation. The functional role was validated in vivo using a SPOCK1-overexpressing xenograft model and ex vivo using patient-derived organoids (PDOs), both confirming increased growth and ß-catenin nuclear localization. Furthermore, data-independent acquisition (DIA) mass spectrometry of SPOCK1-overexpressing tumors revealed pro-tumorigenic signaling including c-Myc activity, oxidative phosphorylation, epithelial-mesenchymal transition. Notably, SPOCK1 drove remodeling of the tumor microenvironment, characterized by desmoplasia and fibrosis. Overall, our findings establish a SPOCK1/Wnt/ß-catenin axis as a novel mechanism driving CRC tumorigenesis and stemness, positioning it as a promising therapeutic target to overcome Wnt-mediated progression and resistance. Overall design: SW480 cells stably overexpressing SPOCK1-flag or vector control were submitted for RNA-Seq