Trafficking mesenchymal stem cell engraftment and differentiation in tumor-bearing mice by bioluminescence imaging.
The objective of the study was to track the distribution and differentiation of mesenchymal stem cells (MSCs) in tumor-bearing mice. The 4T1 murine breast cancer cells were labeled with renilla luciferase-monomeric red fluorescence protein (rLuc-mRFP) reporter gene. The MSCs labeled with firefly luciferase-enhanced green fluorescence protein (fLuc-eGFP) reporter gene (MSCs-R) were isolated from L2G85 transgenic mice that constitutively express fLuc-eGFP reporter gene. To study the tumor tropism of MSCs, we established both subcutaneous and lung metastasis models. In lung metastasis tumor mice, we injected MSCs-R intravenously either on the same day or 4 days after 4T1 tumor cell injection. In subcutaneous tumor mice, we injected MSCs-R intravenously 7 days after subcutaneous 4T1 tumor inoculation. The tumor growth was monitored by rLuc bioluminescence imaging (BLI). The fate of MSCs-R was monitored by fLuc BLI. The localization of MSCs-R in tumors was examined histologically. The osteogenic and adipogenic differentiation of MSCs-R was investigated by alizarin red S and oil red O staining, respectively. The mechanism of the dissimilar differentiation potential of MSCs-R under different tumor microenvironments was investigated. We found that the 4T1 cells were successfully labeled with rLuc-mRFP. The MSCs-R isolated from L2G85 transgenic mice constitutively express fLuc-eGFP reporter gene. When injected intravenously, MSCs-R survived, proliferated, and differentiated in tumor sites but not elsewhere. The localization of GFP(+) MSCs-R in tumor lesions was confirmed ex vivo. In conclusion, the MSCs-R can selectively localize, survive, and proliferate in both subcutaneous tumor and lung metastasis as evidenced by noninvasive bioluminescence imaging and ex vivo validation. The MSCs-R migrated to lung tumor differentiated into osteoblasts, whereas the MSCs-R targeting subcutaneous tumor differentiated into adipocytes.
Wang
Hui
H
Department of Radiology, Bio-X Program, Stanford University School of Medicine, Stanford, California 94305-5484, USA.
Cao
Feng
F
De
Abhijit
A
Cao
Yuan
Y
Contag
Christopher
C
Gambhir
Sanjiv S
SS
Wu
Joseph C
JC
Chen
Xiaoyuan
X
D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods*; D008175:Lung Neoplasms / Q000473:pathology* / Q000556:secondary; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic
C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins