Non-Invasive Fluorescent Monitoring of Ovarian Cancer in an Immunocompetent Mouse Model

Abstract

Ovarian cancers (OCs) are the most lethal gynaecological malignancy, with high levels of relapse and acquired chemo-resistance. Whilst the tumour–immune nexus controls both cancer progression and regression, the lack of an appropriate system to accurately model tumour stage and immune status has hampered the validation of clinically relevant immunotherapies and therapeutic vaccines to date. To address this need, we stably integrated the near-infrared phytochrome iRFP720 at the ROSA26 genomic locus of ID8 mouse OC cells. Intrabursal ovarian implantation into C57BL/6 mice, followed by regular, non-invasive fluorescence imaging, permitted the direct visualization of tumour mass and distribution over the course of progression. Four distinct phases of tumour growth and dissemination were detectable over time that closely mimicked clinical OC progression. Progression-related changes in immune cells also paralleled typical immune profiles observed in human OCs. Specifically, we observed changes in both the CD8+ T cell effector (Teff):regulatory (Treg) ratio, as well as the dendritic cell (DC)-to-myeloid derived suppressor cell (MDSC) ratio over time across multiple immune cell compartments and in peritoneal ascites. Importantly, iRFP720 expression had no detectible influence over immune profiles. This new model permits non-invasive, longitudinal tumour monitoring whilst preserving host–tumour immune interactions, and allows for the pre-clinical assessment of immune profiles throughout disease progression as well as the direct visualization of therapeutic responses. This simple fluorescence-based approach provides a useful new tool for the validation of novel immuno-therapeutics against OC.

DPP4 Inhibitor Sitagliptin Enhances Lymphocyte Recruitment and Prolongs Survival in a Syngeneic Ovarian Cancer Mouse Model

“…The ID8 mouse epithelial ovarian cancer cell line (a gift from Dr. Kathy Roby, Kansas University Medical Center) was maintained in DMEM (Gibco, Palo Alto, CA, USA) containing 4% fetal bovine serum (FBS), 1% penicillin/streptomycin (PS) and 1x insulin-transferrin-selenium (ITS). pROSA -iRFP720 ID8 cells were generated and maintained as previously described [ 22 ].…”

“…However the use of DPP4 inhibitors as a novel immunotherapy for this disease has not yet been shown. In the current study, we sought to determine whether DPP4 inhibition using sitagliptin enhances lymphocyte tumour infiltration in a syngeneic mouse model of EOC [ 22 ] to abrogate tumour-mediated immune suppression and promote antitumour immunity. In the current study, we demonstrated delayed tumour metastasis and increased survival with associated increases in CD8+ T-cell activation, proliferation and CXCR3-mediated T-cell recruitment to ovarian tumour tissue.…”

Use of Transabdominal Ultrasound for the Detection of Intra-Peritoneal Tumor Engraftment and Growth in Mouse Xenografts of Epithelial Ovarian Cancer

“…In-vivo monitoring of EOC cell lines can be accomplished using several well-developed techniques including RFP, GFP, luciferase and ROSA reporter systems [16, 17]. Bioluminescence in vivo imaging system (IVIS) using luciferase reporter containing cell lines has been commonly utilized to track tumor growth over time, but this technique has limitations.…”

Cancer Vaccines: Research and Applications

“…A number of methods for measuring immunity induced by cancer vaccines have been developed, such as bioplex or enzyme linked immunospot (ELISpot) cytokine analysis, cytotoxic T cell activity assays, cytotoxic T cell precursor frequency assays, T cell proliferation, flow cytometry analysis, carboxyfluorescein succinimidyl ester (CFSE) analysis, tetramers, and antibody measurements [30]. In this special issue, Wilson AL et al elegantly present a non-invasive fluorescent imaging method to directly visualize tumor mass and distribution over the course of tumor progression [31]. Changes were also noted in CD8+ T cells, regulatory T cells, dendritic cells, and myeloid derived suppressor cells over time [31], thereby showing a new non-invasive approach for the monitoring of cancer vaccine candidates.…”

“…In this special issue, Wilson AL et al elegantly present a non-invasive fluorescent imaging method to directly visualize tumor mass and distribution over the course of tumor progression [31]. Changes were also noted in CD8+ T cells, regulatory T cells, dendritic cells, and myeloid derived suppressor cells over time [31], thereby showing a new non-invasive approach for the monitoring of cancer vaccine candidates.…”