Brain Tumors Research Today is a free monthly online journal that collates and summarizes the latest research about Brain Tumors, including details on symptoms, benign and malignant tumors, gliomas, screening, treatment.

Gli activity correlates with tumor grade in platelet-derived growth factor-induced gliomas.

Becher OJ, Hambardzumyan D, Fomchenko EI, Momota H, Mainwaring L, Bleau AM, Katz AM, Edgar M, Kenney AM, Cordon-Cardo C, Blasberg RG, Holland EC

Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.

Gli signaling is critical for central nervous system development and is implicated in tumorigenesis. To monitor Gli signaling in gliomas in vivo, we created platelet-derived growth factor-induced gliomas in a Gli-luciferase reporter mouse. We find that Gli activation is found in gliomas and correlates with grade. In addition, we find that sonic hedgehog (SHH) is expressed in these tumors and also correlates with grade. We identify microvascular proliferation and pseudopalisades, elements that define high-grade gliomas as SHH-producing microenvironments. We describe two populations of SHH-producing stromal cells that reside in perivascular niche (PVN), namely low-cycling astrocytes and endothelial cells. Using the Ptc-LacZ knock-in mouse as a second Gli responsive reporter, we show beta-galactosidase activity in the PVN and in some tumors diffusely throughout the tumor. Lastly, we observe that SHH is similarly expressed in human gliomas and note that an intact tumor microenvironment or neurosphere conditions in vitro are required for Gli activity.

Published 2 April 2008 in Cancer Res, 68(7): 2241-9.
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