Inhibition of vasculogenesis, but not angiogenesis, prevents the recurrence of glioblastoma after irradiation in mice
Mitomu Kioi, … , Griffith R. Harsh, J. Martin Brown
Mitomu Kioi, … , Griffith R. Harsh, J. Martin Brown
Published February 22, 2010
Citation Information: J Clin Invest. 2010;120(3):694-705. https://doi.org/10.1172/JCI40283.
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Research Article

Inhibition of vasculogenesis, but not angiogenesis, prevents the recurrence of glioblastoma after irradiation in mice

Abstract

Despite the high doses of radiation delivered in the treatment of patients with glioblastoma multiforme (GBM), the tumors invariably recur within the irradiation field, resulting in a low cure rate. Understanding the mechanism of such recurrence is therefore important. Here we have shown in an intracranial GBM xenograft model that irradiation induces recruitment of bone marrow–derived cells (BMDCs) into the tumors, restoring the radiation-damaged vasculature by vasculogenesis and thereby allowing the growth of surviving tumor cells. BMDC influx was initiated by induction of HIF-1 in the irradiated tumors, and blocking this influx prevented tumor recurrence. Previous studies have indicated that BMDCs are recruited to tumors in part through the interaction between the HIF-1–dependent stromal cell–derived factor–1 (SDF-1) and its receptor, CXCR4. Pharmacologic inhibition of HIF-1 or of the SDF-1/CXCR4 interaction prevented the influx of BMDCs, primarily CD11b+ myelomonocytes, and the postirradiation development of functional tumor vasculature, resulting in abrogation of tumor regrowth. Similar results were found using neutralizing antibodies against CXCR4. Our data therefore suggest a novel approach for the treatment of GBM: in addition to radiotherapy, the vasculogenesis pathway needs to be blocked, and this can be accomplished using the clinically approved drug AMD3100, a small molecule inhibitor of SDF-1/CXCR4 interactions.

Authors

Mitomu Kioi, Hannes Vogel, Geoffrey Schultz, Robert M. Hoffman, Griffith R. Harsh, J. Martin Brown

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Figure 3

The interaction of SDF-1 and CXCR4 promotes tumor influx of BMDCs and restoration of tumor vasculature.

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The interaction of SDF-1 and CXCR4 promotes tumor influx of BMDCs and re...
(A) Irradiation promotes the expression of SDF-1 in U251 i.c. tumor. Representative image of IHC staining for SDF-1. Scale bar: 50 μm. (B) Quantification of SDF-1 in the irradiated tumors. Error bars indicate SEM. ***P < 0.001 versus control. (C) Phosphorylation of CXCR4 on BMDCs in tumors was induced after irradiation. IHC staining for GFP-BM and pCXCR4 in U251 i.c. tumors 3 weeks after 15 Gy whole brain irradiation. Arrowheads indicate phospho-CXCR4 GFP-BM cells. Scale bar: 50 μm. (D) Quantification of pCXCR4 GFP-BM cells in U251 i.c. tumor after irradiation. Error bars indicate SEM. ***P < 0.001. (E) AMD3100 prevents the restoration of tumor blood flow (green) after irradiation. Representative ultrasound images from U251 s.c. tumors treated with 15 Gy irradiation, AMD3100, irradiation+AMD3100, and control. Scale bar: 1 mm. (F) Quantification of blood flow in tumor of E. Blood flow was reduced by irradiation but recovered by 3 weeks. AMD3100 plus IR prevents the recovery of tumor blood flow. Error bars indicate SD. *P < 0.05.