PDGF-B-driven gliomagenesis can occur in the absence of the proteoglycan NG2

The survival curves of NG2-KO mice overexpressing PDGF-B were compared to controls by using a Log-rank test. The characteristics of tumors induced in NG2-KO were compared to those of tumors induced in wild type mice by immunostaining for different cell lineage markers and by transplantation assays in adult mice.We showed that the lack of NG2 does not appreciably affect any of the characterized steps of PDGF-driven brain tumorigenesis, such as oligodendrocyte progenitor cells (OPC) induction, the recruitment of bystander OPCs and the progression to full malignancy, which take place as in wild type animals.Our analysis, using both NG2-KO mice and a miRNA based silencing approach, clearly demonstrates that NG2 is not required for PDGF-B to efficiently induce and maintain gliomas from neural progenitors. On the basis of the data obtained, we therefore suggest that the role of NG2 as a target molecule for glioma treatment should be carefully reconsidered.Gliomas are tumors of the central nervous system often characterized by poor survival. Their most aggressive form, glioblastoma, exhibits a dismal prognosis mainly due to its prominent infiltrative ability and to its high radio- and chemo-resistance. Because of this, it is of primary importance to identify molecules that can be used as therapeutic targets. The transmembrane chondroitin sulfate proteoglycan NG2 has been proposed as one of these candidates [1,2].NG2 is expressed in human gliomas and its expression correlates to their malignancy [3-6] and chemo-resistance [7]. A major role for NG2 in glioma progression could reside in its ability to promote neoangiogenesis [4,8,9] and some reports showed that it could also be involved in other critical processes such as cell migration and cell proliferation [10]. Many of these effects are due to the ability of NG2 to influence extracellular signaling by interacting with integrins [10-12] and growth factor receptors [13-15]. In particular, NG2 was reported to physically inte