Table 3.

Existing mouse models of BRAF V600E-mutated gliomas.

Model type	Cell lines or virus	Host mice used	Age of mice	Tumor type	Injection site	Median survival	Cellular origin	Main findings	Reference
PDX	IC-3635PXA cells with BRAF V600E expression and CDKN2A deficiency	NOD/SCID	ND	PXA	Cerebellum Cerebrum	150-170 days	ND	•Increased proliferation •Loss of GFAP and gain of Vimentin expression •Reactive gliosis •Perivascular metastasis •Xenograft cells with homozygous CDKN2A deletion shifted from disomy to trisomy chromsome 9	(109)
PDX	D645 V600E mutant	Athymic nude	6-8wks old	PXA	Striatum	25-50 days	ND	•Temozolomide, bevacizumab, CPT11 and sorafenib inhibited tumor growth in both V600E-mutant and V600E-non-mutant xenograft models. •MEK inhibition (cobimetinib) but not BRAF inhibition (vemurafenib) inhibited tumor growth	(110)
PDX	BT-40 NCH-MN-1 IC-3635	SCID SCID SCID	ND ND ND	ND ND PXA	ND ND ND	~21 days ~21 days ~28 days	ND ND ND	•Sensitivity of BRAF-mutated tumors to trametinib is due, in part, to MAPK-mediated regulation of TORC1 activity •Resistance to trametinib is driven by upregulated MAPK pathway and downregulated TORC1 pathway •Resistance to trametinib is tumor line-specific and drug-specific	(64)
PDX	DBTRG05-MG AM38	Athymic nude Athymic nude	5wks old 5wks old	Astrocytoma Astrocytoma	Striatum Striatum	~35-100 days ~20 days	ND ND	•DBTRG05-MG xenografts exhibited features including: invasion, analplastic tumor cell morphology, Nestin expression and high mitotic index •Combination therapy using BRAF inhibitor and CDK4/6-specific inhibitor to both cell lines inhibits tumor growth and extends animal survival	(22, 79)
Syngeneic	2341-luc cells with BRAF V600E expression and CDKN2A deficiency	FVB/N NSG	ND ND	Astrocytoma Astrocytoma	Corpus callosum Corpus callosum	58.5 days 45 days	ND	•Tumors co-express GFAP, Olig2, Ki67 and phospho-Erk •Combined BRAF and MEK inhibitor treatment prevented MAPK pathway reactivation and reduced tumor growth	(57)
GEMM	pCAG-Cre-IRES2-GFP or pCAG-Cre-GFP plasmid	Braflsl-V637E/+	E14.5	GG	IUE into the ventricle	–	NPs	•BRAFV600E mutations in neural progenitor cells during development lead to: epileptic seizures, which are often associated with GG and PXA neuronal abnormalities, increased numbers of astro- and oligodendroglia •BRAFV600E-induced epileptogenesis is mediated by RE1-silencing transcription factor (REST), a regulator of ion channels and neurotransmitter receptors associated with epilepsy	(111)
Cre-lox system	CamK2-Cre-expressing adeno-associated virus	Braflsl-V637E/+; Rosa26lsl-tdTomato	P30	GG	Somatosensory cortex	–	NPs
Virus-induced					(S1 cortex)
GEMM Cre-lox system Virus-induced	Cre-expressing adenovirus	BRAFV600Efl/+ BRAFV600Efl/+Ink4a-arf-/-	60 day old 60 day old	Astrocytoma	Subventricular zone	– 70 days	ND	•Tumor formation in mice with concurrent heterozygous BRAFV600E expression and homozygous deletion of Ink4a-Arf upon Ad-Cre injection, but not in mice with BRAFV600E expression alone •Tumors exhibit strong immunoreactivity for Olig2, GFAP and Nestin •Tumors have impaired capacity to differentiate into neurons, OLs and astrocytes; •Tumors have high proliferative rate •Diffuse invasion throughout the cerebral hemisphere and white matter tracts	(22)
GEMM, syngeneic	Olig2-cre;BRAFV600Efl/+ hGFAP-cre;BRAFV600Efl/+ hGFAP-cre;BRAFV600Efl/+Ink4a-arf-/- Ad:cre;BRAFV600Efl/+Ink4a-arf-/-	SCID SCID SCID SCID	ND ND ND ND	Astrocytoma	Subventricular zone	ND ND 112 days 112 days	NPs	•No evidence of tumor formation in the brain of hGFAP-cre;BRAFV600Efl/+ mice. •These mice with BRAF activation alone survived until 3 wks. of age •Orthotopic injection of hGFAP-cre;BRAFV600Efl/+ cells or Olig2-cre;BRAFV600Efl/+ cells into SCID mice do not induce tumor formation	(22)
GEMM RCAS-TVA system virus-induced	RCASBP(A)BRAFV600E	Nestin-TVA/Ink4a/Arf-/-	Newborn	GBM	ND	ND	NPs	•BRAFV600E expression induces aggressive gliomas in mice when combined with Ink4a/Arf loss or activation of the Akt pathway •Tumors with BRAFV600E and Ink4a/Arf deletion do NOT express GFAP, S100 and Olig2, but strongly express Nestin show evidence of diffuse infiltration, aberrant vasculature and necrosis •No evidence of tumor formation in mice injected with BRAFV600E alone	(112)
GEMM RCAS-TVA system virus-induced	RCAS-BRAF VE kin (the V600E mutated BRAF kinase domain)	Nestin-TVA	Neonatal	PA	Hemispheres Brainstem	ND	NPs	•Expression of BRAF VE kin induces tumor formation with strong immunoreactivity for GFAP and weak or negative immunoreactivity for Nestin •Strong phospho-Erk and Ki67 positivity	(113)
GEMM piggyBac transposon system	pGlast-pBase or pNestin-pBase transpose helper plasmids and pBCAG-Flag-BRAFV600E or pBCAG-Flag-BRAFwt donor plasmids	CD1	E14	–	IUE into S1 cortex	–	NPs	•BRAFV600E in neural progenitor cells results in hyperexcitable pyramidal neurons •BRAFV600E disrupts migration of pyramidal neurons destined for upper cortical layers	(114)
GEMM piggyBac transposon system	pCMV-pBase transpose helper plasmid and PB-CAG-BRAFV600E, or PB-CAG-BRAFV600E and -pAkt, or PB-CAG-BRAFV600E, -pAkt and -Cre donor plasmids	CD1 Trp53-/- with a CD1 background	E14 E14	PLNTY GG aGG	IUE into the ventricle IUE into the ventricle IUE into the ventricle	ND ND ND	Glioneural progenitors	•1-hit model: BRAFV600E alone induces tumor formation with oligodendroglial and PLNTY-like features; positive immunoreactivity for MAP2, Olig2 and CD34 •2-hit model: BRAFV600E and Akt activation leads to neoplastic tumor growth, exhibit substantial neuronal activity and epileptogenic propensity; a glioneuronal phenotype immunoreactive for MAP2, GFAP, NeuN and Olig2; tumors that recapitulate GG-like features •3-hit model: BRAFV600E/pAkt/Trp53-loss tumors exhibit glioneuronal clonality with aGG-like features	(115)
GEMM RCAS-TVA system CRISPR-Cas9 system	Plasmid carrying the BRAF gRNA and the BRAFV637E Homology-Directed-Repair donor was cloned into a lentiviral vector and transduced into the p53-null TVA-Cas9 neural stem cells	NOD/SCID	4-5wks old	ND	ND	66 days	NPs	•BRAF mutant/p53-null tumors show strong immunoreactivity for Ki67, Olig2 and Nestin, and elevated MAPK kinase activity as revealed by upregulated phospho-Erk •Resistance to dabrafenib monotherapy is driven by the upregulation of the MAPK signaling pathway	(116)

PDX: Patient-derived xenografts; GEMM: Genetically modified mouse models; ND: Not determined; PXA: pleomorphic xanthoastrocytoma; GG: ganglioglioma; GBM: glioblastoma multiforme; PA: pilocytic astrocytoma; PLNTY: polymorphous low-grade neuroepithelial tumors of the young; aGG: anaplastic GGs; IUE: in utero electroporation; NPs: neural progenitors.