Toll-Like Receptors as Therapeutic Targets in Central Nervous System Tumors

Table 1

TLR expression in normal and neoplastic CNS cells.

Receptor	Cell/Tissue	mRNA/Protein	Specie	References
TLR1	Microglia, neurons	+/+	human, mouse	[66–68]
	Astrocytes	+/nd	human, mouse	[40]
	Glioma ∗(GL261, U251, U87, SF126)	+/-	human, mouse	[40, 53]
	Astrocytoma, Glioblastoma ∗(U87MG, A172)	+/+	human	[69]
TLR2	Oligodendrocytes	+/nd	human	[66]
	Microglia, astrocytes, neurons	+/+	human, mouse	[66–68, 70–74]
	Glioma ∗(GL261, U251, U87, SF126)	+/-	human, mouse	[40, 53]
	Medulloblastoma	nd/+	human	[75]
	Astrocytoma, Glioblastoma ∗(U87MG, A172)	+/+	human	[69]
TLR3	Astrocytes	+ /-	human, mouse	[66, 70]
	Oligodendrocytes, microglia, neurons	+/+	human	[66–68, 70, 72, 73, 76]
	Glioma ∗(GL261, SF126)	+/+	human, mouse	[40, 53]
	Medulloblastoma	nd/+	human	[75]
TLR4	Microglia, neurons	+/+	human	[66–68, 72]
	Astrocytes	+/+	human, mouse	[40, 71, 72]
	Glioma ∗(GL261, U251, U87, SF126)	+/-	human, mouse	[40, 53]
	Astrocytoma, Glioblastoma ∗(U87MG, A172, U118, LN229)	+/+	human	[62, 69, 77]
TLR5	Microglia	nd/+	human	[66]
	Astrocytes	+/+	human, mouse	[40, 71, 72]
	Glioma ∗(GL261, U251, U87)	+/-	human, mouse	[40]
	Astrocytoma, Glioblastoma ∗(U87MG, A172)	+/+	human	[69]
TLR6	Microglia, microglia ∗(EOC13)	+/+	human, mouse	[66, 67, 78]
	Neurons	+/+	mouse	[72]
	Astrocytes	+/nd	human, mouse	[40]
	Glioma ∗(U251; SF126)	+/-	human	[40, 53]
	Astrocytoma, Glioblastoma ∗(U87MG, A172)	+/+	human	[69]
TLR7	Microglia	+/nd	human	[66, 67]
	Neurons	+/+	human	[76]
	Astrocytes	+/nd	human, mouse	[40, 79]
	Glioma ∗(GL261, U251, U87)	+/-	human, mouse	[40]
TLR8	Microglia	+/nd	human	[66, 67]
	Neurons	+/+	human, mouse	[66, 72, 76]
	Astrocytes	+/nd	human, mouse	[40, 67]
	Glioma ∗(GL261, U251, U87)	+/-	human, mouse	[40]
TLR9	Neurons (differentiated from ∗SH-SY5Y)	nd/+	human	[72, 80]
	Astrocytes	+/nd	human, mouse	[40, 71, 72]
	Glioma ∗(GL261, U251, U87, SF126)	+/+	human, mouse	[40, 53, 77]
TLR10	Microglia	nd/+	mouse	[66]
	Glioblastoma ∗(T387, T3832, T4121)	+/+	human	[81]
TLR11	Microglia	nd/+	mouse	[66]
	Brain	+/-	mouse	[82]
TLR12	Brain	+/-	mouse	[82]
TLR13	Brain	+/-	mouse	[82]

+, positive expression; -, negative expression; nd, not determined expression; ∗cell lines.