An Orthotopic Model of Serous Ovarian Cancer in Immunocompetent Mice for in vivo Tumor Imaging and Monitoring of Tumor Immune Responses
Summary
To study in vivo tumor growth and tumor microenvironment, we used a syngeneic and orthotopic mouse model of ovarian cancer in immunocompetent animals. We transduced a mouse tumor cell line (MOV1) with Katushka fluorescent protein (MOV1KAT) and here we show its orthotopic implantation in ovary and in vivo imaging.
Abstract
Background: Ovarian cancer is generally diagnosed at an advanced stage where the case/fatality ratio is high and thus remains the most lethal of all gynecologic malignancies among US women 1,2,3. Serous tumors are the most widespread forms of ovarian cancer and 4,5 the Tg-MISIIR-TAg transgenic represents the only mouse model that spontaneously develops this type of tumors. Tg-MISIIR-TAg mice express SV40 transforming region under control of the Mullerian Inhibitory Substance type II Receptor (MISIIR) gene promoter 6. Additional transgenic lines have been identified that express the SV40 TAg transgene, but do not develop ovarian tumors. Non-tumor prone mice exhibit typical lifespan for C57Bl/6 mice and are fertile. These mice can be used as syngeneic allograft recipients for tumor cells isolated from Tg-MISIIR-TAg-DR26 mice.
Objective: Although tumor imaging is possible 7, early detection of deep tumors is challenging in small living animals. To enable preclinical studies in an immunologically intact animal model for serous ovarian cancer, we describe a syngeneic mouse model for this type of ovarian cancer that permits in vivo imaging, studies of the tumor microenvironment and tumor immune responses.
Methods: We first derived a TAg+ mouse cancer cell line (MOV1) from a spontaneous ovarian tumor harvested in a 26 week-old DR26 Tg-MISIIR-TAg female. Then, we stably transduced MOV1 cells with TurboFP635 Lentivirus mammalian vector that encodes Katushka, a far-red mutant of the red fluorescent protein from sea anemone Entacmaea quadricolor with excitation/emission maxima at 588/635 nm 8,9,10. We orthotopically implanted MOV1Kat in the ovary 11,12,13,14 of non-tumor prone Tg-MISIIR-TAg female mice. Tumor progression was followed by in vivo optical imaging and tumor microenvironment was analyzed by immunohistochemistry.
Results: Orthotopically implanted MOV1Kat cells developed serous ovarian tumors. MOV1Kat tumors could be visualized by in vivo imaging up to three weeks after implantation (fig. 1) and were infiltrated with leukocytes, as observed in human ovarian cancers 15 (fig. 2).
Conclusions: We describe an orthotopic model of ovarian cancer suitable for in vivo imaging of early tumors due to the high pH-stability and photostability of Katushka in deep tissues. We propose the use of this novel syngeneic model of serous ovarian cancer for in vivo imaging studies and monitoring of tumor immune responses and immunotherapies.
Protocol
Discussion
Surgery and Orthotopic injections
Orthotopic injection in ovarian bursa demands training and precision. Thus
- In case of poor surgical experience, practice with cadavers first.
- Use preferentially multiparous females (one or two litters) as they develop bigger ovaries over time which facilitates injection and increase survival to compare with nulliparous females.
- Due to the small size of the mouse ovarian bursa, the use of the smallest available needle size i…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
This work was supported by the NIH grant P01 AI 068730 (SNC, NS), the NIH grant CA016520/ TAPITMAT (NS), the private funding from the Claneil Foundation (NS), and the ovarian SPORE grant to FCCC and University of Pennsylvania (P50 CA83638) and the Fox Chase Cancer Center Core Grant (P30 CA06927) (DCC). The authors thank the excellent technical assistance of the Optical/Bioluminescence Core Facility directed by Dr. E.J. Delikatny at the University of Pennsylvania, Anthony Secreto from the Stem Cell and Xenograft Core directed by Dr. G. Danet-Desnoyers at the University of Pennsylvania Cancer Center for training SNC to orthotopic injection technique and Denada Dangaj at the University of Pennsylvania/ OCRC for assisting on the surgery.
Materials
| Material Name | Tipo | Company | Catalogue Number | Comment |
|---|---|---|---|---|
| DMEM-GLUTAMAX | Invitrogen | 10564-011 | ||
| PBS | Gibco | 14040 | ||
| Versene | Lonza | 17-711E | ||
| Heating pad | Deltaphase | 39 DP | ||
| Povidone pads | Dynarex | 1108 | ||
| Alcohol pads | Fisher | 06-669-62 | ||
| Artificial tears ointment | Phoenix Pharma., Inc. | 17845-153 | ||
| Ketoprofen | Fort Dodge laboratories | |||
| 3cc/insulin syringe | BD | 309301 | ||
| Polyg Polyglycolic Acid suture/needle (3/8 19mm) | Syneture | 9612-31 | ||
| Tissue adhesive | Vetbond | 3M | ||
| Vet Bactrim/ oral suspension | Hi-tech Pharmacal | 840823 | ||
| IVIS-Lumina | Caliper lifesciences | |||
| Isofluorane | Phoenix Pharma., Inc. | J108013 | ||
| Fetal Bovine Serum, Qualified | Invitrogen | 10437036 | ||
| Penicillin/streptomycin | Gibco | 15140 | ||
| TurboFP635 mammalian vector | Evrogen | FP721 | ||
| T175 flasks | cellstar | 660-190 |
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