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Review
. 1998 Nov;153(5):1333-9.
doi: 10.1016/S0002-9440(10)65717-3.

Is angiopoietin-2 necessary for the initiation of tumor angiogenesis?

J Laurén  1 , Y Gunji, K Alitalo
Affiliations
Review

Is angiopoietin-2 necessary for the initiation of tumor angiogenesis?

J Laurén et al. Am J Pathol. 1998 Nov.
No abstract available

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Figures

Figure 1.
Figure 1.
Hypothetical role of Ang-2 in tumor angiogenesis. Ang-1 expression in mesenchymal cells around vessels with Tie-2 receptor-positive ECs leads to constitutive Tie-2 activation and signaling (1). Increased production of VEGF and bFGF in tumors may contribute to the observed up-regulation of Ang-2 focally in the angiogenic EC sprouts. In addition, regional hypoxia may up-regulate Tie-2 and Ang-2 expression via the endothelial PAS domain protein 1 (EPAS1/HIF-2) transcription factor activation. By inhibiting Ang-1 - Tie-2 signaling, Ang-2 may disrupt the interactions between ECs and their microenvironment, including PCs and SMCs. This may sensitize the ECs to the mitogenic and chemotactic signals mediated by tumor-secreted angiogenic factors and release them from growth inhibition caused by PCs (2). When ECs are in an activated state, Ang-1 secreted by the tumor cells and Ang-2 produced by the endothelium may promote angiogenesis in concert with VEGF(3).
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Comment on

References

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