A Three-dimensional Model of Spheroids to Study Colon Cancer Stem Cells
January 22nd, 2021
This protocol presents a novel, robust, and reproducible culture system to generate and grow three-dimensional spheroids from Caco2 colon adenocarcinoma cells. The results provide the first proof-of-concept for the appropriateness of this approach to study cancer stem cell biology, including the response to chemotherapy.
This new method of spheroid cultures can be used to study the tumorigenicity to analyze the presence of different populations of cancer stem cells and also can be nicely applied to for through high put screen for new drugs. This is a robust and repetitive cultured system for generating large number of homogeneously sized spheroids. Moreover, these spheroids can be used to study cancerous stem cells.
This method is set up to study chronic cancer biology but it can be easily set up to study other cancers by changing the 3D culture conditions. Be sure to watch for bubbles in the medium, to not move the plate too much during the spheroids formation and to be careful when harvesting the spheroids into the strainer. Begin by pre treating the wells of a 24 well plate with 500 micro liters of Anti-Adherence Rinsing Solution per well.
After a few seconds centrifuge the plate in swinging-bucket rotor and rinse each well with 2 milliliters of warm Basal medium. Observe the plate under the microscope to ensure that the bubbles have been completely removed from the micro wells. If no bubbles are observed, rinse the wells again before adding one milliliter of warm DMEM basement membrane matrix medium to each well.
To induce spheroid formation, see the desired concentration of Caco-2 cells in a 2D mono layer in a 10 centimeter dish in DMEM supplemented with 10%FBS and 1%antibiotics. For the culture at 37 degrees Celsius and 5%carbon dioxide in a humidified atmosphere. When an 80%confluency is reached, wash the cells with five milliliters of PBS before treating the culture with two milliliters of Trypsin-EDTA for two to five minutes at 37 degrees Celsius and 5%carbon dioxide.
When the cells have detached neutralize the Trypsin with four milliliters of complete DMEM. After counting, collect the cells by centrifugation and resuspend the palette in the appropriate volume of DMEM basement membrane matrix medium to achieve the desired concentration of cells in one milliliter of medium per well. Add one milliliter of cells to each well of the prepaid 24 well plate, followed by the addition of one milliliter of DMEM basement membrane matrix medium to each well.
After seeding, immediately centrifuge the plate and use a light microscope to verify that the cells have been evenly distributed across the micro wells. Then place the plate in the cell culture incubator for 48 hours without disturbing the cells. To harvest the spheroids, at the end of the incubation, use a serological pipette and half of the supernatant in each well to gently dislodge the spheroids from their micro wells.
When all of the spheroids have been detached use the pipette to carefully transfer the 3D cultures from each well unto a 37 micron reversible strainer on top of a 15 milliliter conical tube. Wash each well three times with one milliliter of prewarmed Basal medium per wash to collect any remaining spheroids and add these additional spheroids to the strainer. After the last wash check the plate under the microscope to confirm that all of the spheroids have been removed from the micro wells.
Then invert the strainer over a new 15 milliliter tube and wash the bottom of the strainer with fresh DMEM basement membrane matrix medium to collect the spheroids into the tube. Spheroids are rising from 500 cells demonstrate the most homogeneous increase in size over time. With 500 and 600 cells per spheroid determine to be the optimal number of cells under which good growth and low variability can be achieved.
The addition of basement membrane matrix enhances spheroid growth and homogeneity. In long term culture, the cells appear as dense multi layers at day three. While flattened cells arranged in mono layers are clearly visible at day 10.
Interestingly, a lumen appears within the spheroids from day five onward. In addition, a clear increase in proliferating cell nuclear antigen positive cells is observed at days five and seven that declines by day 10. Surprisingly, activated Caspace 3 is observed in very few cells at days three and five only.
While high levels of Beta-catenin expression are observed at every time point. The potential of the spheroids to differentiate into Anterosites is evidenced by their Alkaline Phosphatase and solute carrier family 2A5 mRNA expression. In addition, this spheroids express typical cancer stem cell markers and respond to combination chemotherapy treatments routinely administered to colorectal cancer patients.
So spheroids are composed of different cell populations. They then can be nicely used to analyze cell specifical responses to stimuli such as refractors and eventually for drug responses.
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Overview
This protocol presents a robust culture system for generating three-dimensional spheroids from Caco2 colon adenocarcinoma cells. This method allows for the study of cancer stem cell biology and their response to chemotherapy.
Key Study Components
Area of Science
- Neuroscience
- Oncology
- Cell Biology
Background
- Understanding cancer stem cells is crucial for developing effective therapies.
- 3D spheroid cultures mimic in vivo tumor environments.
- This method can be adapted for various cancer types.
- Robustness and reproducibility are essential for experimental validity.
Purpose of Study
- To establish a reliable method for spheroid culture from Caco2 cells.
- To investigate the tumorigenicity and cancer stem cell populations.
- To facilitate high-throughput screening for new drugs.
Methods Used
- Pre-treatment of wells with Anti-Adherence Rinsing Solution.
- Careful handling to avoid bubbles during spheroid formation.
- Harvesting spheroids using a strainer.
- Monitoring culture conditions for optimal growth.
Main Results
- Successful generation of homogeneously sized spheroids.
- Demonstrated applicability for studying cancer stem cells.
- Potential for drug screening applications.
- Adaptability to other cancer types by modifying culture conditions.
Conclusions
- This method provides a new tool for cancer research.
- It enhances the understanding of cancer stem cell dynamics.
- Future studies can leverage this system for therapeutic development.
Frequently Asked Questions
Executive Industry Relevance
This 3D spheroid model addresses the critical need for preclinical systems that recapitulate tumor heterogeneity and cancer stem cell (CSC) phenotypes, enabling more predictive evaluation of therapeutic targets and drug responses in colorectal cancer research. By providing a reproducible platform for long-term CSC enrichment and chemotherapy response assessment, the method supports early-stage target validation and lead identification efforts with improved translational confidence.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of CSC heterogeneity and tumorigenic potential through differential proliferation patterns and lumen-like structures within spheroids.
- Operational Value: Supports functional target validation by enriching for CSCs expressing established markers, facilitating mechanistic de-risking of therapeutic hypotheses.
Screening & Assay Development
- Scientific Value: Generates homogeneously sized spheroids from defined cell inputs, creating a standardized system for quantitative drug response analysis.
- Operational Value: Compatible with high-throughput screening workflows due to robustness, reproducibility, and ease of spheroid harvesting using strainer-based methods.
Translational & Preclinical Research
- Scientific Value: Demonstrates CSC marker expression and response to clinically relevant combination chemotherapy, enabling preclinical modeling of treatment resistance and sensitivity.
- Operational Value: Maintains CSC phenotypes over long-term culture, supporting longitudinal studies of drug efficacy and tumor recurrence mechanisms.
Pipeline & Workflow Integration
The method fits within the discovery continuum from target hypothesis testing through lead identification to preclinical validation, particularly for oncology programs focused on CSC-directed therapies and resistance mechanisms.
- Discovery Biology: Facilitates pathway clarification and biological de-risking by modeling CSC niches and differential drug responses in a 3D context.
- Screening: Enables assay standardization through size-homogeneous spheroid formation, supporting reliable compound screening against CSC-enriched populations.
- Analytics: Provides quantitative readouts via CSC marker expression, proliferation markers (PCNA), and apoptosis markers (activated Caspase-3) to compare treatment conditions.
- Translational Research: Connects to preclinical continuity by modeling chemotherapy response in a disease-relevant system that mirrors colorectal adenocarcinoma heterogeneity.
- Enterprise Reuse: Adaptable to other cancer types by modifying 3D culture conditions, positioning it as a reusable platform across oncology discovery programs.
Operational & Enterprise Impact
- Scientific Value: Enhances predictive confidence in target validation by capturing CSC-driven tumor heterogeneity and functional stemness properties absent in 2D models.
- Operational Value: Delivers reproducibility and scalability through standardized seeding, anti-adherence pretreatment, and strainer-based harvesting, reducing variability in spheroid generation.
- Strategic Value: Improves go/no-go decision-making by enabling early assessment of CSC-targeting compounds and resistance mechanisms, reducing late-stage biological risk.
- Portfolio Impact: Supports risk-adjusted prioritization of leads based on CSC modulation and chemotherapy response data from a physiologically relevant model.
Implementation Considerations
- Requires expertise in 3D cell culture techniques, including anti-adherence surface treatment and careful handling to prevent bubble formation during spheroid initiation.
- Dependent on access to basement membrane matrix (e.g., Matrigel) and standard cell culture equipment including centrifuges, strainers (37 micron), and inverted microscopes for monitoring.
- Necessitates cross-team standardization of seeding density (500–600 cells/spheroid) and incubation timing to ensure homogeneity and reproducibility across experiments.
- Adaptation to other cancer types requires optimization of basement membrane concentration and culture duration based on cell line-specific adhesion and spheroid formation kinetics.
- Practical limitations include the need for gentle handling during harvest to avoid spheroid disruption and potential variability in lumen formation timing across batches.
