title: Preservation of tumor-host immune interactions with luciferase-tagged imaging in a murine model of ovarian cancer.
abstract: BACKGROUND
  Ovarian cancer is immunogenic and residual tumor volume after surgery is known to be prognostic. Ovarian cancer often follows a recurring-remitting course and microscopic disease states may present ideal opportunities for immune therapies. We sought to establish the immune profile of a murine model of ovarian cancer that allows in vivo tumor imaging and the quantitation of microscopic disease.
  
  
  CONCLUSIONS
  Baseline imaging and weight measurements were taken within 1 and 2 weeks after intraperitoneal tumor injection, respectively. Significantly higher photons per second from baseline imaging were first observed 5 weeks after tumor cell injection (p < 0.05) and continued to be significant through 8 weeks after injection (p < 0.01), whereas a significant increase in weight above baseline was not observed until day 56 (p < 0.0001). Expression of luc2 in ID8 cells did not alter the cellular immune microenvironment of the tumor. FOXP3+ T cells were more likely to be detected in the intraepithelial compartment and CD4+ T cells in the stroma as compared to CD3+ T cells, which were found equally in stroma and intraepithelial compartments.
  
  
  CONCLUSIONS
  Use of an intraperitoneal tumor expressing a codon-optimized firefly luciferase in an immunocompetent mouse model allows tumor quantitation in vivo and detection of microscopic tumor burdens. Expression of this foreign protein does not significantly effect tumor engraftment or the immune microenvironment of the ID8 cells in vivo and may allow novel immunotherapies to be assessed in a murine model for their translational potential to ovarian cancers in remission or minimal disease after primary cytoreductive surgery or chemotherapy.
  
  
  METHODS
  Mouse ovarian surface epithelial cells from C57BL6 mice transformed after serial passage in vitro were transduced with a lentiviral vector expressing a codon optimized firefly luciferase (luc2). Cell lines were selected and luc2 expression functionally confirmed in vitro. Cell lines were intraperitoneally (IP) implanted in albino C57BL/6/BrdCrHsd-Tyrc mice and albino B6(Cg)-Tyrc-2 J/J mice for serial imaging. D-luciferin substrate was injected IP and tumors were serially imaged in vivo using a Xenogen IVIS. Tumor take, weights, and luminescent intensities were measured. Immunohistochemistry was performed on tumors and assessed for immune infiltrates in stromal and intraepithelial compartments.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195 USA ; Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: John B
authors.identifier: 0000-0002-3018-7879
authors.initials: JB
authors.lastname: Liao
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195 USA ; Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: Kelsie J
authors.initials: KJ
authors.lastname: Ovenell
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195 USA ; Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA ; Swarthmore College, 500 College Ave, Swarthmore, PA 19081 USA.
authors.forename: Erin E M
authors.initials: EE
authors.lastname: Curtis
authors.affiliation: Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: Denise L
authors.initials: DL
authors.lastname: Cecil
authors.affiliation: Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: Marlese R
authors.initials: MR
authors.lastname: Koehnlein
authors.affiliation: Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: Lauren R
authors.initials: LR
authors.lastname: Rastetter
authors.affiliation: Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: Ekram A
authors.initials: EA
authors.lastname: Gad
authors.affiliation: Tumor Vaccine Group, Center for Translational Medicine in Women's Health, University of Washington, 850 Republican St., Seattle, WA 98109 USA.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Disis
keywords: Immune therapies; Mouse models; Ovarian cancer