We describe the establishment of orthotopic colorectal tumors via injection of tumor cells or organoids into the cecum of mice and the subsequent isolation of circulating tumor cells (CTCs) from this model.
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Method Article
Isolation of Circulating Tumor Cells in an Orthotopic Mouse Model of Colorectal Cancer
In This Article
Summary
Abstract
Despite the advantages of easy applicability and cost-effectiveness, subcutaneous mouse models have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Orthotopic mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in hollow organs such as the large bowel. In order to produce uniform tumors which reliably grow and metastasize, standardized techniques of tumor cell preparation and injection are critical.
We have developed an orthotopic mouse model of colorectal cancer (CRC) which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor cells from either primary tumors, 2-dimensional (2D) cell lines or 3-dimensional (3D) organoids are injected into the cecum and, depending on the metastatic potential of the injected tumor cells, form highly metastatic tumors. In addition, CTCs can be found regularly. We here describe the technique of tumor cell preparation from both 2D cell lines and 3D organoids as well as primary tumor tissue, the surgical and injection techniques as well as the isolation of CTCs from the tumor-bearing mice, and present tips for troubleshooting.
Introduction
Colorectal cancer (CRC) is one of the most common causes of cancer death in western countries.1 While the primary tumor can often be resected, the occurrence of distant metastases dramatically worsens the prognosis and often leads to death.2,3 The biological correlate of metastasis is circulating tumor cells (CTCs), which detach from the tumor, survive in circulation, attach to the epithelium in the target organ, invade the organ and ultimately outgrow to new lesions.4 Although CTCs are known to be of prognostic relevance,5,
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Protocol
The animal experiments presented here were independently reviewed and permitted by an institutional and a governmental Animal Care and Use Committee and were conducted according to Federation of Laboratory Animal Science Associations (FELASA) guidelines. All possible measures were taken to minimize suffering including anesthesia and analgesia or, if necessary, premature euthanasia.
1. Preparation of Cells and Organoids
NOTE: Use a volume of 20 µL with 100,000 cells for each injection. Use basement membrane matrix (BMM) in order to prevent leakage and ensure standardized injection. In order to ensure r....
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Results
The successful and reproducible generation of colorectal tumors in this model critically depends on accurate injection of the cells without spillage or leakage. If this is achieved, this model is extremely reliable and very rarely results in artificial peritoneal dissemination. The growth kinetics of the tumors as well as their dissemination patterns depend on the biology of the used organoids and cells.15 While HCT116 cells reliably metastasize to the liver in thi.......
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Discussion
Despite their preclinically proven activity in subcutaneous mouse models, the great majority of novel compounds fail in clinical trials and never reach the clinic.11 This obvious insufficiency of subcutaneous mouse models to accurately simulate the biology and growth patterns of tumors has led to the development of orthotopic mouse models based on the injection of tumor cells directly into the original organ.
Orthotopic mouse models are able to simulate the biology and .......
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Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was supported by the German Research foundation (WE 3548/4-1) and Roland-Ernst-Stiftung für Gesundheitswesen (1/14).
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| Cell culture Media and Components | |||
| Advanced DMEM F12 | Invitrogen | 12634010 | DMEM/ F12 +++ medium |
| HEPES (1 M) | Life Technologies GmbH | 15630056 | DMEM/ F12 +++ medium |
| Glutamax-I Supplement (200 mM) | Life Technologies GmbH | 35050038 | DMEM/ F12 +++ medium |
| Penicillin/Streptomycin (PenStrep) | Life Technologies GmbH | 15140122 | DMEM/ F12 +++ medium |
| DMEM | Life Technologies GmbH | 61965026 | basic medium of 2D cell lines (DMEM/10% FCS) |
| Fetal Calf Serum (FCS) | BIOCHROM AG | S 0115 | basic medium of 2D cell lines (DMEM/10% FCS) |
| TrypLE Express enzymatic dissociation buffer | Life Technologies GmbH | 12604021 | |
| Matrigel basement membrane matrix (BMM, phenol red free) | CORNING B.V. Life Sciences | 356231 | |
| Dulbecco's Phosphate Buffered Saline | Life Technologies GmbH | 14190169 | |
| Trypsin-EDTA (0.25%, Phenol-Red) | Life Technologies GmbH | 25200072 | |
| 6-/48-well plates with lid | CORNING | 3516/3548 | |
| cell culture flask 75 cm², 250 mL | VWR International GmbH | 734-2066 | |
| cell culture flask 150 cm², 600 mL | Corning B.V. Life Sciences | 355001 | |
| Eppendorf tubes 1,5 mL / 2 mL | Sarstedt AG & Co. | 72.706.400/ 72.695.400 | |
| 15 mL, 50 mL centrifuge tubes | Greiner-Bio-One GmbH | 188271/227270 | |
| TC10 Counting Slides (for TC20 Counting Machine) | Bio-Rad Laboratories GmbH | 1450016 | |
| Pasteur pipettes (glass, 150 mm) | Fisher Scientific GmbH | 11546963/ FB50251 | thinly pulled by using a bunsen burner |
| gentleMACS Dissociator | Miltenyi Biotec | 130-093-235 | for primary tumor tissue preparation |
| MACSmix Tube Rotator | Miltenyi Biotec | 130-090-753 | for primary tumor tissue preparation |
| gentleMACS C Tubes | Miltenyi Biotec | 130-093-237 | for primary tumor tissue preparation |
| Human Tumor Dissociation Kit | Miltenyi Biotec | 130-095-929 | for primary tumor tissue preparation |
| Falcon 70 µm Cell Strainer | Corning B.V. Life Sciences | 352350 | for primary tumor tissue preparation |
| Name | Company | Catalog Number | Comments |
| Surgical Equipment | |||
| Sevoflurane | AbbVie Germany GmbH & Co. KG | - | |
| Medical oxygen | Air Liquide Medical GmbH | - | |
| Buprenorphine | Temgesic | - | |
| Bepanthen - opthalmic ointment | Bayer Vital GmbH | 10047757 | |
| Normal saline 0.9% (E154) | Serumwerk Bernburg AG | 10013 | |
| Aqua ad injectabilia | Braun | 235144 | |
| 1 mL Syringe (without dead volume) - Injekt-F SOLO | Braun/neoLab | 194291661 | |
| 30G injection needle | BECTON DICKINSON | 304000 | |
| cellulose swabs | Lohmann & Rauscher Deutschland | 13356 | |
| Micro-Adson Forceps | FST - Fine Science Tools | 11018-12 | |
| Iris Scissor - ToughCut | FST - Fine Science Tools | 14058-11 | |
| Olsen-Hegar Needle Holder | FST - Fine Science Tools | 12002-12 | |
| AutoClip Kit | FST - Fine Science Tools | 12020-00 | |
| PDS Z1012H 6/0 C1 (surgical suture) | Johnson & Johnson Medical GmbH | Z1012H | |
| Table Top Research Anesthesia Machine w/O2 Flush and a Sevoflurane Vaporizer | Parkland Scientific | V3000PS/PK | |
| UltraMicro Pump with Micro4 Controller | World Precision Instruments | UMP3-4 | equipment for highly controlled orthotopic injection |
| Footswitch for SYS-Micro4 Controller | World Precision Instruments | 15867 | equipment for highly controlled orthotopic injection |
| Three-axis Manual Micromanipulator | World Precision Instruments | M325 | equipment for highly controlled orthotopic injection |
| Magnetic Stand for Micromanipulator | World Precision Instruments | M10 | equipment for highly controlled orthotopic injection |
| Steel Base Plate for M10 Magnetic Stand | World Precision Instruments | 5479 | equipment for highly controlled orthotopic injection |
| Hot Plate 062 | Labotect | 13854 | |
| Isis - Hair shaver | AESCULAP - Braun | - | |
| Binocular Surgical Microscope | Parkland Scientific | VS-2Z | |
| Name | Company | Catalog Number | Comments |
| CTC isolation | |||
| EDTA | Roth | 8040.1 | |
| Density gradient medium – Ficoll | StemCell - Lymphoprep | 7801 | |
| Alexa Fluor 488 anti-human CD326 (EpCAM) Antibody clone 9C4 | BioLegend | 324210 | |
| Alexa Fluor 488 anti-mouse CD326 (EpCAM) Antibody clone G8.8 | BioLegend | 118210 | |
| Petri Dish, ø 60 x 15 mm, 21 cm², Vent | Greiner bio-one | 628102 | |
| Fluorescence Cell Culture Microscope | Leica | ||
| Transferman 4r Micromanipulator | Eppendorf | ||
| CellTram Air | Eppendorf | aspiration pump connected to the micromanipulator | |
| Dmz Universal Microelectrode Puller | Dagan Corporation | required for the manufacturing of micro capillaries for single cell aspiration | |
| Prism Glass Capillaries | Dagan Corporation | ||
| PAP pen | Abcam | ab2601 | |
| Dulbecco's Phosphate Buffered Saline | Life Technologies GmbH | 14190169 | picking buffer |
| Fetal Calf Serum (FCS) | BIOCHROM AG | S 0115 | picking buffer |
| Penicillin/Streptomycin (PenStrep) | Life Technologies GmbH | 15140122 | picking buffer |
| EDTA | Roth | 8040.1 | picking buffer |
| Name | Company | Catalog Number | Comments |
| Immunohistochemistry | |||
| Purified anti-human CD326 (EpCAM) antibody clone 9C4 | BioLegend | 324201 | EpCAM immunohistochemistry (cf, fig 2C) |
| HRP rabbit anti-mouse IgG | Abcam | ab97046 | EpCAM immunohistochemistry (cf, fig 2C) |
References
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- Weitz, J., Koch, M., Debus, J., Höhler, T., Galle, P. R., Büchler, M. W. Colorectal cancer. Lancet. 365 (9454), 153-165 (2005).
- Schölch, S., et al. Circulating tumor cells of colorectal cancer. Cancer Cell Microenviron. 1 (5), (2014).
- ....
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