title: Color-Coded Imaging of Syngeneic Orthotopic Malignant Lymphoma Interacting with Host Stromal Cells During Metastasis.
abstract: BACKGROUND
  The EL4 cell line was previously derived from a lymphoma induced in a C57/BL6 mouse by 9,10-dimethyl-1,2-benzanthracene. In a previous study, EL4 lymphoma cells expressing red fluorescent protein (EL4-RFP) were established and injected into the tail vein of C57/BL6 green fluorescent protein (GFP) transgenic mice. Metastasis was observed at multiple sites which were also enriched with host GFP-expressing stromal cells. In the present study, our aim was to establish an orthotopic model of EL4-RFP.
  
  
  METHODS
  In the present study, EL4-RFP lymphoma cells were injected in the spleen of C57/BL6 GFP transgenic mice as an orthotopic model of lymphoma. Resultant primary tumor and metastases were imaged with the Olympus FV1000 scanning laser confocal microscope.
  
  
  RESULTS
  EL4-RFP metastasis was observed 21 days later. EL4-RFP tumors in the spleen (primary injection site), liver, supra-mediastinum lymph nodes, abdominal lymph nodes, bone marrow, and lung were visualized by color-coded imaging. EL4-RFP metastases in the liver, lymph nodes, and bone marrow in C57/BL6 GFP mice were rich in GFP stromal cells such as macrophages, fibroblasts, dendritic cells, and normal lymphocytes derived from the host animal. Small tumors were observed in the spleen, which were rich in host stromal cells. In the lung, no mass formation of lymphoma cells occurred, but lymphoma cells circulated in lung peripheral blood vessels. Phagocytosis of EL4-RFP lymphoma cells by macrophages, as well as dendritic cells and fibroblasts, were observed in culture.
  
  
  CONCLUSIONS
  Color-coded imaging of the lymphoma microenvironment suggests an important role of stromal cells in lymphoma progression and metastasis.
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan AntiCancer, Inc., San Diego, CA, U.S.A Department of Surgery, University of California San Diego, San Diego, CA, U.S.A. all@anticancer.com asue@gifu-u.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suetsugu
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Hasegawa
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Aoki
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kunisada
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tsurumi
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: AntiCancer, Inc., San Diego, CA, U.S.A Department of Surgery, University of California San Diego, San Diego, CA, U.S.A. all@anticancer.com asue@gifu-u.ac.jp.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hoffman
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003116:Color; D003952:Diagnostic Imaging / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism* / Q000556:secondary; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism*; D008223:Lymphoma / Q000378:metabolism* / Q000473:pathology; D008822:Mice, Transgenic; D017154:Stromal Cells / Q000378:metabolism*; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein
keywords: C57/BL6 GFP mice; RFP; imaging; liver metastasis; malignant lymphoma