Overview of current pre-clinical models to study gliomas
| Model . | Method . | Name/aliases . | Origin . | Characteristics . | Growth condition/maintenance . | Main feature . | Limitations . | Citations . |
|---|---|---|---|---|---|---|---|---|
| In vitro | Immortalized adherent cell lines | Established/traditional/classic cancer cell lines | Enzymatic disaggregation of isolated tumor explants into individual cells with the capacity to proliferate indefinitely in the presence of fetal bovine serum and defined nutrients. Cancer cell lines constitute one of the most common cancer models due to their simplicity, inexpensiveness, and high proliferation rates. | High proliferation rates, harbor genotypes somewhat similar to primary tumor (e.g., TP53, PTEN). | Media with serum fetal bovine | Accessibility, reproducibility | Genomically unstable, deficient in many/most properties of human gliomas (e.g., invasiveness in vivo). | Richter et al. (2021) |
| Glioma cancer stem-like cells | GSCs, TICs, CSCs | Freshly resected and dissociated GBM tissue. | Self-renewal capacity, genetically stable upon multiple passages, more closely resembles primary tumors, retains patient’s tumor subtype. | Neurobasal media with B27, EGF, and FGF | Phenocopy patient’s transcriptomic subtype | Cycling cells overrepresented, more difficult and expensive to grow than legacy glioma lines. | Lee et al. (2006) | |
| 3D tumor spheroids/organoids | Cancer tumor organoids, CSC organoids | Primary-derived GSCs, explants from xenograft models, genetically engineered glioma cells, or direct patient samples. | Self-organization, differentiation, increased cell diversity, phenotypically diverse populations. | Scaffold ECM like Matrigel or hanging drop, ultra-low round-bottom plates | Hypoxic gradients | Does not recapitulate the microenvironment of the brain or glioma-host cell, glioma brain ECM interactions. | Hubert et al. (2016) | |
| Ex vivo | Co-cultures of hESCs-derived mini-brains and GBM stem cells | GLICOs | hPSCs-derived cerebral organoids co-cultured with GSCs. | Mimic various aspects of the human microenvironment, preserve native cytoarchitecture and cell interactions, intratumor heterogeneity. | Cerebral organoid media | Human tumor–host interactions | Lacks spatial patterns of tumor heterogeneity and is devoid of vascular or immunologic components. | Linkous et al. (2019) |
| Tumor explants | PDOs, GBM organoids | 1-mm tumor chunk explants cultured in serum-free conditions and without added growth factors or extracellular matrix. | Amenable for high-throughput screening, preserve some tumor microenvironment (TME). | Growth factors-free chemically defined medium | Maintain original patient’s TME | Inter-patient variable efficiency, tissue starts dying almost immediately so system under stress, thus best for short-term assays. | Jacob et al. (2020) | |
| Microfabrication techniques | GBM-on-a-chip | Multi-region layout for brain vascular growth, immune cell seeding, and tumor growth, as well as a central area for cell culture medium infusion. | Allow an oxygen gradient to simulate the role of hypoxia in GBM tissue organization. Further enhancement of its physiological relevance. | Brain-mimicking, HA-rich Matrigel ECM | Spatial heterogeneity | Artificial and relatively simplistic constitution of TME, low-throughput scale. | Cui et al. (2020) | |
| In vivo | Syngeneic: Spontaneously and carcinogenic | Spontaneous tumor, carcinogen-induced model | Tumor cells implanted into immunocompetent mice of the same genetic background, through (1) the use of carcinogens to induce tumorigenesis (either in vitro or in vivo) or (2) by leveraging spontaneous tumor formation in dogs. | Immunogenic, suitable for immunotherapy studies. | Serial transplantation or passaging in vitro; naturally occurring in the case of dogs | Immunogenecity | In the case of dogs, rare and difficult to obtain. Spontaneous tumors of non-human origin are not generally reflective of the GBM genome. | Oh et al. (2014) |
| Syngeneic: GEMM | GEMM | By inducing tumor formation through targeted modifications to the mouse genome. Combination of at least two or more genetic events, such as alteration in PTEN, NF1, TP53, KRAS, EGFR, and PDGF β on immune-competent mice. | Useful model to study gliomagenesis. | Serial transplantation or passaging in vitro | Recapitulates tumor initiation | Mouse tumor origin, gene-driven tumorigenesis with limited heterogeneity, mouse brain microenvironment. | Richmond and Su (2008) | |
| Xenografts: Orthotopic | PDX | Hetero-transplantation of human cancer cells into immune-deficient mouse strains such as nude mice, non-obese diabetic mice, severe combined immunodeficient mice. | Traditional cell lines typically form well-demarcated, solid-like tumors. In contrast, GSCs and PDX more closely mimic the infiltrative growth patterns seen in human gliomas. | Patient-derived, GSCs cells injected into the brain parenchyma | Gold standard for tumorigenicity test | Mouse TME, lack of immune cells. | Sarkaria et al. (2006) | |
| Xenografts: Heterotopic | PDX | By implanting glioma cells subcutaneously. Engraftment success rates can be notably enhanced. | Quick growth, easily scalable. | Legacy glioma cell lines (not GSCs) injected subcutaneously | Better engraftment | Non-brain TME, true GSCs do not grow well in a microenvironment other than the CNS. | Akter et al. (2021) | |
| Zebrafish xenograft models | Zebrafish PDX | Zebrafish embryos. | Transparent nature in early developmental stages, genetic and anatomical similarities with humans. | Maintained in standard zebrafish facility conditions | Rapid development, cost-effective, high-throughput drug screening | Temperature regulation, differences in pharmacokinetics and pharmacodynamics. Do not recapitulate GBM biology, genomics, or human TME. | Alberti et al. (2024) |
| Model . | Method . | Name/aliases . | Origin . | Characteristics . | Growth condition/maintenance . | Main feature . | Limitations . | Citations . |
|---|---|---|---|---|---|---|---|---|
| In vitro | Immortalized adherent cell lines | Established/traditional/classic cancer cell lines | Enzymatic disaggregation of isolated tumor explants into individual cells with the capacity to proliferate indefinitely in the presence of fetal bovine serum and defined nutrients. Cancer cell lines constitute one of the most common cancer models due to their simplicity, inexpensiveness, and high proliferation rates. | High proliferation rates, harbor genotypes somewhat similar to primary tumor (e.g., TP53, PTEN). | Media with serum fetal bovine | Accessibility, reproducibility | Genomically unstable, deficient in many/most properties of human gliomas (e.g., invasiveness in vivo). | Richter et al. (2021) |
| Glioma cancer stem-like cells | GSCs, TICs, CSCs | Freshly resected and dissociated GBM tissue. | Self-renewal capacity, genetically stable upon multiple passages, more closely resembles primary tumors, retains patient’s tumor subtype. | Neurobasal media with B27, EGF, and FGF | Phenocopy patient’s transcriptomic subtype | Cycling cells overrepresented, more difficult and expensive to grow than legacy glioma lines. | Lee et al. (2006) | |
| 3D tumor spheroids/organoids | Cancer tumor organoids, CSC organoids | Primary-derived GSCs, explants from xenograft models, genetically engineered glioma cells, or direct patient samples. | Self-organization, differentiation, increased cell diversity, phenotypically diverse populations. | Scaffold ECM like Matrigel or hanging drop, ultra-low round-bottom plates | Hypoxic gradients | Does not recapitulate the microenvironment of the brain or glioma-host cell, glioma brain ECM interactions. | Hubert et al. (2016) | |
| Ex vivo | Co-cultures of hESCs-derived mini-brains and GBM stem cells | GLICOs | hPSCs-derived cerebral organoids co-cultured with GSCs. | Mimic various aspects of the human microenvironment, preserve native cytoarchitecture and cell interactions, intratumor heterogeneity. | Cerebral organoid media | Human tumor–host interactions | Lacks spatial patterns of tumor heterogeneity and is devoid of vascular or immunologic components. | Linkous et al. (2019) |
| Tumor explants | PDOs, GBM organoids | 1-mm tumor chunk explants cultured in serum-free conditions and without added growth factors or extracellular matrix. | Amenable for high-throughput screening, preserve some tumor microenvironment (TME). | Growth factors-free chemically defined medium | Maintain original patient’s TME | Inter-patient variable efficiency, tissue starts dying almost immediately so system under stress, thus best for short-term assays. | Jacob et al. (2020) | |
| Microfabrication techniques | GBM-on-a-chip | Multi-region layout for brain vascular growth, immune cell seeding, and tumor growth, as well as a central area for cell culture medium infusion. | Allow an oxygen gradient to simulate the role of hypoxia in GBM tissue organization. Further enhancement of its physiological relevance. | Brain-mimicking, HA-rich Matrigel ECM | Spatial heterogeneity | Artificial and relatively simplistic constitution of TME, low-throughput scale. | Cui et al. (2020) | |
| In vivo | Syngeneic: Spontaneously and carcinogenic | Spontaneous tumor, carcinogen-induced model | Tumor cells implanted into immunocompetent mice of the same genetic background, through (1) the use of carcinogens to induce tumorigenesis (either in vitro or in vivo) or (2) by leveraging spontaneous tumor formation in dogs. | Immunogenic, suitable for immunotherapy studies. | Serial transplantation or passaging in vitro; naturally occurring in the case of dogs | Immunogenecity | In the case of dogs, rare and difficult to obtain. Spontaneous tumors of non-human origin are not generally reflective of the GBM genome. | Oh et al. (2014) |
| Syngeneic: GEMM | GEMM | By inducing tumor formation through targeted modifications to the mouse genome. Combination of at least two or more genetic events, such as alteration in PTEN, NF1, TP53, KRAS, EGFR, and PDGF β on immune-competent mice. | Useful model to study gliomagenesis. | Serial transplantation or passaging in vitro | Recapitulates tumor initiation | Mouse tumor origin, gene-driven tumorigenesis with limited heterogeneity, mouse brain microenvironment. | Richmond and Su (2008) | |
| Xenografts: Orthotopic | PDX | Hetero-transplantation of human cancer cells into immune-deficient mouse strains such as nude mice, non-obese diabetic mice, severe combined immunodeficient mice. | Traditional cell lines typically form well-demarcated, solid-like tumors. In contrast, GSCs and PDX more closely mimic the infiltrative growth patterns seen in human gliomas. | Patient-derived, GSCs cells injected into the brain parenchyma | Gold standard for tumorigenicity test | Mouse TME, lack of immune cells. | Sarkaria et al. (2006) | |
| Xenografts: Heterotopic | PDX | By implanting glioma cells subcutaneously. Engraftment success rates can be notably enhanced. | Quick growth, easily scalable. | Legacy glioma cell lines (not GSCs) injected subcutaneously | Better engraftment | Non-brain TME, true GSCs do not grow well in a microenvironment other than the CNS. | Akter et al. (2021) | |
| Zebrafish xenograft models | Zebrafish PDX | Zebrafish embryos. | Transparent nature in early developmental stages, genetic and anatomical similarities with humans. | Maintained in standard zebrafish facility conditions | Rapid development, cost-effective, high-throughput drug screening | Temperature regulation, differences in pharmacokinetics and pharmacodynamics. Do not recapitulate GBM biology, genomics, or human TME. | Alberti et al. (2024) |
TIC: tumor-initiating cells, CSC: cancer stem cells, hESC: human embryonic stem cell, shPSC: human pluripotent stem cells, EGF: epidermal growth factor, FGF: fibroblast growth factor, MGMT: O(6)-methylguanine-DNA methyltransferase, TMZ: temozolomide.