| Abstract: |
Tumor angiogenesis is essential for malignant growth and metastasis. Bone marrow (BM)-derived endothelial progenitor cells (EPC) contribute to angiogenesis-mediated tumor growth. EPC ablation can reduce tumor growth; however, the lack of a marker that can track EPCs from the BM to tumor neovasculature has impeded progress in understanding the molecular mechanisms underlying EPC biology. Here, we report the use of transgenic mouse and lentiviral models to monitor the BM-derived compartment of the tumor stroma; this approach exploits the selectivity of the transcription factor inhibitor of DNA binding 1 (Id1) for EPCs to track EPCs in the BM, blood, and tumor stroma, as well as mature EPCs. Acute ablation of BM-derived EPCs using Id1-directed delivery of a suicide gene reduced circulating EPCs and yielded significant defects in angiogenesis-mediated tumor growth. Additionally, use of the Id1 proximal promoter to express microRNA-30-based short hairpin RNA inhibited the expression of critical EPC-intrinsic factors, confirming that signaling through vascular endothelial growth factor receptor 2 is required for EPC-mediated tumor biology. By exploiting the selectivity of Id1 gene expression in EPCs, our results establish a strategy to track and target EPCs in vivo, clarifying the significant role that EPCs play in BM-mediated tumor angiogenesis. ©2010 AACR. |
| Keywords: |
signal transduction; unclassified drug; angiogenesis inhibitor; nonhuman; mouse; animals; mice; microrna; gene expression; gene expression profiling; cell maturation; inhibitor of differentiation 1; protein targeting; animal experiment; animal model; cell line, tumor; vasculotropin receptor 2; angiogenesis; neovascularization, pathologic; mice, inbred c57bl; mice, transgenic; endothelium cell; endothelial cells; cell growth processes; stroma; stem cells; upregulation; hematopoietic stem cell; inhibitor of differentiation protein 1; gene silencing; up-regulation; tumor growth; dna binding; stromal cells; chickens; suicide gene; intrinsic factor; microrna 30; carcinoma, lewis lung
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