title: Imaging the Interaction of Pancreatic Cancer and Stellate Cells in the Tumor Microenvironment during Metastasis.
abstract: OBJECTIVE
  Pancreatic stellate cells are involved in fibrosis of pancreatic cancer termed desmoplasia, which may contribute to both pancreatic cancer growth and metastasis, as well as to drug resistance. A better understanding of pancreatic cancer-cell interactions with stellate cells is therefore critical to our ability to develop effective anti-metastatic therapeutics for pancreatic cancer.
  
  
  METHODS
  The human pancreatic cancer cell line XPA-1 was engineered to express green fluorescent protein (GFP) in the nucleus and red fluorescent protein (RFP) in the cytoplasm. Pancreatic stellate cells were engineered to express RFP. The pancreatic cancer cells and stellate cells were co-cultured and their interaction was imaged in vitro. The pancreatic cancer cells and stellate cells were then co-injected in the spleen of transgenic cyan fluorescent protein (CFP) nude mice and imaged in liver, lung and diaphragm metastasis.
  
  
  RESULTS
  The interaction of the pancreatic cancer cells expressing GFP in the nucleus and RFP in the cytoplasm and stellate cells expressing RFP was first imaged in vitro. The intimate relationship between the two cell types could be seen. Three hours after splenic co-injection, dual-color pancreatic cancer cells and pancreatic stellate cells were found distributed in the host liver. By 28 days after splenic co-injection of the pancreatic cancer and stellate cells, liver metastases were observed in host CFP nude mice. Metastases were also observed in the lung and diaphragm. Stellate cells were observed along with the pancreatic cancer cells at all metastatic sites suggesting that stellate cells may be necessary for metastasis. With high-resolution intravital imaging afforded by the Olympus FV1000 confocal microscope, the interaction of the dual-colored pancreatic cancer cells and the RFP-expressing pancreatic stellate cells could be clearly imaged in the liver and other metastases, further suggesting that stellate cells participate in metastasis formation.
  
  
  CONCLUSIONS
  Pancreatic cancer cells and stellate stem cells form a very close relationship and accompany each other to distant metastatic sties. Our hypothesis is that pancreatic stellate cells form a niche for metastasis of pancreatic cancer.
authors.affiliation: AntiCancer, Inc., San Diego, CA, U.S.A. Department of Surgery, University of California, San Diego, CA, U.S.A. Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suetsugu
authors.affiliation: Department of Surgery, University of California, San Diego, CA, U.S.A.
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Snyder
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Hisataka
authors.initials: H
authors.lastname: Moriwaki
authors.affiliation: Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Shigetoyo
authors.initials: S
authors.lastname: Saji
authors.affiliation: Department of Surgery, University of California, San Diego, CA, U.S.A.
authors.forename: Michael
authors.initials: M
authors.lastname: Bouvet
authors.affiliation: AntiCancer, Inc., San Diego, CA, U.S.A. Department of Surgery, University of California, San Diego, CA, U.S.A. all@anticancer.com.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hoffman
mesh_terms: D000818:Animals; D060846:Cell Engineering; D002467:Cell Nucleus / Q000235:genetics / Q000473:pathology; D003593:Cytoplasm / Q000235:genetics / Q000473:pathology; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D057054:Molecular Imaging; D009362:Neoplasm Metastasis; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D058954:Pancreatic Stellate Cells / Q000473:pathology*; D059016:Tumor Microenvironment / Q000235:genetics*
chemical_list: C485182:Cyan Fluorescent Protein; D049452:Green Fluorescent Proteins
keywords: CFP nude mouse; GFP; Pancreatic cancer; RFP; color-coded fluorescence imaging; dual color cells; interaction; stellate cells