title: Mesenchymal stem cells enhance growth and metastasis of colon cancer.
abstract: Recently, mesenchymal stem cells (MSCs) were reported to migrate to tumor stroma as well as injured tissue. We examined the role of human MSCs in tumor stroma using an orthotopic nude mice model of KM12SM colon cancer. In in vivo experiments, systemically injected MSCs migrated to the stroma of orthotopic colon tumors and metastatic liver tumors. Orthotopic transplantation of KM12SM cells mixed with MSCs resulted in greater tumor weight than did transplantation of KM12SM cells alone. The survival rate was significantly lower in the mixed-cell group, and liver metastasis was seen only in this group. Moreover, tumors resulting from transplantation of mixed cells had a significantly higher proliferating cell nuclear antigen labeling index, significantly greater microvessel area and significantly lower apoptotic index. Splenic injection of KM12SM cells mixed with MSCs, in comparison to splenic injection of KM12SM cells alone, resulted in a significantly greater number of liver metastases. MSCs incorporated into the stroma of primary and metastatic tumors expressed α-smooth muscle actin and platelet-derived growth factor receptor-β as carcinoma-associated fibroblast (CAF) markers. In in vitro experiments, KM12SM cells recruited MSCs, and MSCs stimulated migration and invasion of tumor cells through the release of soluble factors. Collectively, MSCs migrate and differentiate into CAFs in tumor stroma, and they promote growth and metastasis of colon cancer by enhancing angiogenesis, migration and invasion and by inhibiting apoptosis of tumor cells.
authors.affiliation: Department of Medicine and Molecular Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Shinagawa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kitadai
authors.forename: Miwako
authors.initials: M
authors.lastname: Tanaka
authors.forename: Tomonori
authors.initials: T
authors.lastname: Sumida
authors.forename: Michiyo
authors.initials: M
authors.lastname: Kodama
authors.forename: Yukihito
authors.initials: Y
authors.lastname: Higashi
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Wataru
authors.initials: W
authors.lastname: Yasui
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D003110:Colonic Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary*; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D017154:Stromal Cells / Q000473:pathology