PFDN2 stabilizes PYCR2 to activate Wnt/β-catenin signaling and promote colorectal cancer progression

Colorectal Cancer (CRC) progression entails coordinated gene dysregulation and rewiring of signaling networks. Here, we investigated whether prefoldin subunit 2 (PFDN2) contributes to CRC progression by stabilizing pyrroline-5-carboxylate reductase 2 (PYCR2) and thereby modulating Wnt/β-catenin signaling. Integrated analyses of TCGA-COAD/READ and Other public datasets showed that PFDN2 and PYCR2 are upregulated in CRC, positively correlated, and associated with poorer prognosis. These findings were corroborated in a 30-pair immunohistochemistry (IHC) cohort, and target modulation was confirmed by quantitative Real-Time PCR and Western blotting. Gain- and loss-of-function studies showed that PFDN2 promotes, whereas its knockdown suppresses, CRC cell proliferation and migration in vitro; in vivo, PFDN2 silencing reduced xenograft growth and Ki-67/β-catenin expression. PYCR2 was likewise elevated in CRC, linked to adverse clinicopathologic features, and enhanced proliferative and migratory phenotypes. Mechanistically, co-immunoprecipitation and immunofluorescence analyses revealed a PFDN2–PYCR2 interaction with predominantly cytoplasmic colocalization. PFDN2 manipulation altered PYCR2 protein but not mRNA levels; cycloheximide chase and MG132 rescue experiments indicated that PFDN2 stabilizes PYCR2 by limiting proteasome-dependent degradation. PFDN2 or PYCR2 depletion reduced TOP/FOPflash reporter activity, nuclear β-catenin accumulation, and expression of canonical Wnt targets, whereas PYCR2 re-expression partially restored these readouts and migratory capacity in PFDN2-silenced cells. Pharmacologic inhibition of canonical Wnt/β-catenin signaling attenuated the pro-proliferative and pro-migratory effects of PFDN2 or PYCR2 overexpression. The PFDN2–PYCR2–Wnt/β-catenin axis appears to be involved in CRC progression, and both proteins may have potential value as prognostic biomarkers and as candidates for further investigation as therapeutic targets.

Colorectal cancer; PFDN2; PYCR2; Proteostasis; Tumor progression; Wnt/β-catenin.