Proteogenomic Characterization Reveals Metabolic Vulnerabilities and Aberrant Phosphorylation in Colorectal...

Colorectal liver metastasis (CRLM) is one of the leading death causes among colorectal cancer (CRC) patients, yet its underlying molecular events remain poorly understood, particularly at the proteomic and phosphoproteomic levels. A proteogenomic analysis combining genomics, transcriptomics, proteomics, and phosphoproteomics is performed on 102 samples from 34 treatment-naïve CRLM patients, including primary CRC, adjacent normal colorectal, and matched liver metastasis tissues. CRC cell lines, organoids, mouse models, and an independent patient cohort are used to validate the findings. Proteomics and phosphoproteomics show profoundly dysregulated pathways in liver metastasis tissues, notably disruptions in carbon metabolism. Functional validation using CRC organoids and mouse models demonstrates that the one-carbon metabolism enzyme SHMT1 promotes CRC tumorigenesis and metastasis via formate-mediated AMPK inhibition, whereas PIM kinase-dependent NDRG1 Ser330 phosphorylation exacerbates liver metastasis by promoting ubiquitin-dependent degradation of NDRG1. Unsupervised clustering identifies two proteomic subtypes of liver metastasis samples with distinct clinical outcomes: a poor-prognosis C1 (metabolism) subtype and a better-prognosis C2 (RNA function) subtype. Considering expression frequency, specificity, and functional relevance, FTCD, GPD1, SOD2, and EIF4B Ser422 phosphorylation are further identified and validated as subtype prognostic biomarkers. This study provides critical insights into the molecular mechanisms underlying CRLM and offers resources for high-risk metastatic CRC.