title: In Vivo Model for Testing Effect of Hypoxia on Tumor Metastasis.
abstract: Hypoxia has been implicated in the metastasis of Ewing sarcoma (ES) by clinical observations and in vitro data, yet direct evidence for its pro-metastatic effect is lacking and the exact mechanisms of its action are unclear. Here, we report an animal model that allows for direct testing of the effects of tumor hypoxia on ES dissemination and investigation into the underlying pathways involved. This approach combines two well-established experimental strategies, orthotopic xenografting of ES cells and femoral artery ligation (FAL), which induces hindlimb ischemia. Human ES cells were injected into the gastrocnemius muscles of SCID/beige mice and the primary tumors were allowed to grow to a size of 250 mm3. At this stage either the tumors were excised (control group) or the animals were subjected to FAL to create tumor hypoxia, followed by tumor excision 3 days later. The efficiency of FAL was confirmed by a significant increase in binding of hypoxyprobe-1 in the tumor tissue, severe tumor necrosis and complete inhibition of primary tumor growth. Importantly, despite these direct effects of ischemia, an enhanced dissemination of tumor cells from the hypoxic tumors was observed. This experimental strategy enables comparative analysis of the metastatic properties of primary tumors of the same size, yet significantly different levels of hypoxia. It also provides a new platform to further assess the mechanistic basis for the hypoxia-induced alterations that occur during metastatic tumor progression in vivo. In addition, while this model was established using ES cells, we anticipate that this experimental strategy can be used to test the effect of hypoxia in other sarcomas, as well as tumors orthotopically implanted in sites with a well-defined blood supply route.
authors.affiliation: Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center.
authors.forename: Sung-Hyeok
authors.initials: SH
authors.lastname: Hong
authors.affiliation: Department of Nursing, Georgetown University, School of Nursing and Health Studies; Department of Human Science, Georgetown University, School of Nursing and Health Studies.
authors.forename: Jason U
authors.initials: JU
authors.lastname: Tilan
authors.affiliation: Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center.
authors.forename: Susana
authors.initials: S
authors.lastname: Galli
authors.affiliation: Department of Human Science, Georgetown University, School of Nursing and Health Studies.
authors.forename: Rachel
authors.initials: R
authors.lastname: Acree
authors.affiliation: School of Medicine, Georgetown University Medical Center.
authors.forename: Katherine
authors.initials: K
authors.lastname: Connors
authors.affiliation: Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center.
authors.forename: Akanksha
authors.initials: A
authors.lastname: Mahajan
authors.affiliation: Department of Human Science, Georgetown University, School of Nursing and Health Studies.
authors.forename: Larissa
authors.initials: L
authors.lastname: Wietlisbach
authors.affiliation: Department of Human Science, Georgetown University, School of Nursing and Health Studies.
authors.forename: Taylor
authors.initials: T
authors.lastname: Polk
authors.affiliation: Department of Pathology and Neuropathology, Medical University of Gdańsk.
authors.forename: Ewa
authors.initials: E
authors.lastname: Izycka-Swieszewska
authors.affiliation: Department of Oncology, Georgetown University Medical Center.
authors.forename: Yi-Chien
authors.initials: YC
authors.lastname: Lee
authors.affiliation: Department of Oncology, Georgetown University Medical Center.
authors.forename: Luciane R
authors.initials: LR
authors.lastname: Cavalli
authors.affiliation: Department of Oncology, Georgetown University Medical Center.
authors.forename: Olga C
authors.initials: OC
authors.lastname: Rodriguez
authors.affiliation: Department of Oncology, Georgetown University Medical Center; Department of Pathology, Georgetown University Medical Center.
authors.forename: Chris
authors.initials: C
authors.lastname: Albanese
authors.affiliation: Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center; jbk4@georgetown.edu.
authors.forename: Joanna B
authors.initials: JB
authors.lastname: Kitlinska
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D000860:Hypoxia / Q000473:pathology*; D051379:Mice; D016513:Mice, SCID; D009362:Neoplasm Metastasis / Q000473:pathology*; D009368:Neoplasm Transplantation; D012512:Sarcoma, Ewing / Q000473:pathology*