Table 4 Benefits and limitations of CCA experimental models
From: Criteria for preclinical models of cholangiocarcinoma: scientific and medical relevance
Model | Benefits | Limitations |
|---|---|---|
In vivo models | ||
Engrafted models: xenograft | Engraftment of human cells or tissue Ectopic engraftment inexpensive and easy to implement Easy-to-measure ectopic tumours Commonly used for drug testing | Defective immune system Ectopic allograft poorly relevant Rate of human CCA tissue ectopic engraftment (PDX) very low Orthotopic engraftment difficult to perform |
Engrafted models: allograft | Full immune system Ideal for studying tumour–stroma interplay Fully compatible for testing immunotherapy-based therapies | Ectopic allograft poorly relevant Orthotopic engraftment difficult to perform |
Chemically induced | Recapitulate development of CCA (TAA) with pre-cancerous disease history Long-term furan treatment induces 100% of tumour incidence | Highly variable Control tissue: isolated bile duct and not whole liver |
GEMM | Design to mimic genetic alterations in human CCA Model of advanced CCA Valuable tool for testing targeted therapies | Fast tumour development Origin of CCA multiple Appearance of mixed HCC–CCA tumour Costly |
In vitro models | ||
2D culture with cell lines or primary cells | Easy and low maintenance costs High experimental reproducibility Large panels of cell lines commercially available Cells available with genetic alteration(s) | Absence of stromal cells Cultures grown as a monolayer |
3D culture recapitulating a tumour organization: spheroids | Can be patient-derived Increased complexity through 3D multicellular aggregates of epithelial cells and stromal cells Recapitulate the gradient of oxygen supply and drug diffusion | Limited use for high-throughput analysis Often made from cell lines Do not fully reflect the polyclonal nature of a CCA tumour |
3D culture recapitulating a tumour organization: organoids | Increased complexity by 3D tumour cell growth in ECM Well-established protocol Specific mutations can be introduced in non-tumour organoids to analyse CCA driver mutations | Low initiation efficiency from human tumours An established line does not fully reflect the polyclonal nature of the original tumour Overgrowth of non-tumour cells on culture initiation Absence of stromal cells |
