MSC1 Cells Suppress Colorectal Cancer Cell Growth via Metabolic Reprogramming, Laminin-Integrin Adhesion Signaling, Oxidative Stress Resistance, and a Tumor-Suppressive Secretome.

Background/Objectives: Mesenchymal stem cells (MSCs) possess immunomodulatory properties, tumor-homing, and low immunogenicity, making them attractive for cell-based cancer therapies, but their role in colorectal cancer (CRC) remains controversial. The MSC1 phenotype, a pro-inflammatory, tumor-suppressive state induced by short-term, low-dose LPS activation via TLR4, has shown therapeutic promise but remains poorly characterized in CRC. We aimed to elucidate MSC1's tumor-suppressive mechanisms and validate its activity against CRC cells using an integrated bioinformatics and in vitro approach. Methods: We constructed a high-confidence protein-protein interaction (PPI) network in Wharton's jelly-derived MSCs (WJ-MSCs) following TLR4 activation to uncover enriched signaling pathways, transcriptional regulators, and secreted factors. Functional and transcriptional enrichment analyses pinpointed key mechanisms. We then co-cultured MSC1 cells with CRC cells to assess effects on proliferation and metabolism. Results: Network analysis revealed six tumor-suppressive mechanisms of MSC1 cells: (i) Metabolic reprogramming via enhanced glucose and lipid uptake, phosphoinositide signaling, and membrane/protein recycling, (ii) Robust antioxidant defenses, including SOS signaling and system xc⁻, (iii) Extracellular matrix stabilization and laminin-111-integrin-mediated adhesion, (iv) Secretome with direct anti-cancer effects, (v) Regulation of survival and cancer-associated fibroblasts (CAFs) formation inhibition through balanced proliferation, apoptosis, and epigenetic signals, (vi) Controlled pro-inflammatory signaling with anti-inflammatory feedback. In vitro, MSC1 cells significantly suppressed CRC cell proliferation and metabolic activity versus controls. Conclusions: This study provides the first mechanistic map of MSC1's tumor-suppressive functions in CRC, extending beyond immunomodulation to include metabolic competition, ECM stabilization, and anti-cancer secretome activity. These findings establish MSC1 cells as a novel therapeutic strategy for CRC in cell-based cancer therapies.