Limitation of in vivo models investigating angiogenesis in breast cancer.
MSCs reside within their niche and pathologic conditions such as hypoxia and inflammation can lead to mobilization and migration of Mesenchymal Stem Cells (MSCs). Xenograft animal models using immundeficient mouse demonstrated that MSCs migrated to and distributed throughout the tumors and were found to engraft into tumor stroma and vasculature. In contrast, MSCs primarily incorporated within tumor-capsula and did not invade the tumor using immuncompetent tumor allograft models. Here we hypothesize that MSCs migrate primarily towards an inflammatory milieu independent of the underlying biological process causing the inflammation. Murine MSCs (mASCs) were isolated from subcutaneous fat tissues and transduced at passage 0 with lentiviral vector encoding green fluorescent protein (GFP) and luciferase reporter. Breast cancer was established in BALB/c mice by subcutaneous injection of 4T1 cells into the left mammary fat pad. E. coli were injected subcutaneously in the right 4th mammary fat pad. After 24 h luciferase labeled mASCs were administered intraperitoneal (i.p.) and monitored with IVIS Bioluminescence camera for 72 hours. Control group received either tumor implantation or E. coli injection. MSCs significantly migrated towards tumor when compared to control mice without tumor or inflammatory process. However, mASCs injected in 4T1 bearing mice with E. coli only migrated towards the bacterial inflammatory focus. Our results substantiate the notation the MSCs response predominantly to the inflammatory milieu created by bacteria or tumor rather than specifically to the tumor. Thus, it is suggested that the migration of MSCs in immunodeficient mice depends on cancer secreted cytokines due to the lack of the inflammatory response by the immune system. Therefore, in vivo studies investigating the role of MSCs in tumor angiogenesis have shown controversy results and should be interpreted with caution in terms of tumor secreted cytokine dependent stem cell migration.
Department of Obstetrics and Gynecology, University Medical Center Regensburg, Regensburg, Germany.
Sanga
S
Gehmert
Sebastian
S
Gehmert
Xiaowen
X
Bai
Silvan
S
Klein
Olaf
O
Ortmann
Lukas
L
Prantl
D000273:Adipose Tissue / Q000473:pathology; D000818:Animals; D001943:Breast Neoplasms / Q000098:blood supply*; D002465:Cell Movement; D054338:Cell Transdifferentiation; D060833:Cellular Microenvironment; D016207:Cytokines / Q000502:physiology; D004195:Disease Models, Animal; D004927:Escherichia coli Infections / Q000150:complications; D005260:Female; D006801:Humans; D007121:Immunocompetence; D016867:Immunocompromised Host; D007249:Inflammation; D008163:Luminescent Measurements; D008325:Mammary Neoplasms, Experimental / Q000098:blood supply / Q000150:complications / Q000276:immunology / Q000503:physiopathology; D059630:Mesenchymal Stem Cells / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000503:physiopathology*; D014183:Transplantation, Heterologous; D059016:Tumor Microenvironment
D016207:Cytokines