Mesenchymal Stem/Stromal Cells Exert Trophic Effect on Colorectal Cancer Metastasis to the Liver

Colorectal Cancer (CRC) is the third most common cancer in the world. CRC tends to metastasize to the liver, which may occur in 20% to 70% of patients and represents the major cause of death. Mesenchymal Stem/stromal cells (MSCs) have shown to be able to migrate to CRC site and play an important role in tumor progression. We have previously identified a resident MSC population in the liver. Therefore, this study aims to investigate whether there is infiltration of MSCs into patient CRC Liver Metastasis (CRC-LM) and their potential effects on tumor cell growth. By culturing resected patient CRC-LM tissue, we observed the emerging of fibroblast-like cells. Further phenotype and functional characterization confirmed their bonafide MSCs features. In situ staining with a well-established MSCs marker showed a significant enrichment of candidate MSCs in patient CRC-LM, particularly the tumor-stromal area. Moreover, MSCs secreted trophic factors significantly increased colony formation and growth of a metastatic CRC cell line. In summary, we found infiltration and enrichment of MSCs in CRC-LM patient, which could in turn nourish tumor cells.