Journal of Cell Science, Vol 105, Issue 4 1013-1024, Copyright © 1993 by Company of Biologists

JOURNAL ARTICLES

Paracrine induction of angiogenesis in vitro by Swiss 3T3 fibroblasts

R Montesano, MS Pepper and L Orci
Department of Morphology, University Medical Center, Geneva, Switzerland.

During angiogenesis, normally quiescent endothelial cells that line existing microvessels are induced to invade the surrounding extracellular matrix and to form capillary sprouts in response to paracrine factors released by neighboring cell types. In an attempt to mimic the physiological conditions under which angiogenesis is triggered in vivo, we have designed two co-culture systems that are suitable for the study of paracrine interactions between microvascular endothelial cells and cell types that might produce angiogenic factors. In the first model, cells to be co-cultured with endothelial cells were suspended within a collagen gel and overlaid with an additional collagen gel devoid of cells, onto which bovine microvascular endothelial cells were subsequently seeded and grown to confluence. In the second model, a small collagen gel disc containing a suspension of endothelial cells was embedded into a larger, cell-free collagen gel disc, which in turn was surrounded by an annular collagen gel containing other cell types. We show that Swiss 3T3 fibroblasts and their 3T3-L1 substrain induce the formation of capillary-like tubes by endothelial cells in these co-culture systems, whereas Balb 3T3 cells, as well as a number of other fibroblasts and epithelial cells, lack this ability. Thus, endothelial cells grown on a collagen gel containing Swiss 3T3 or 3T3-L1 cells invaded the underlying matrix to form a network of interconnecting tubules. In addition, Swiss 3T3 and 3T3-L1 cells stimulated extensive radial outgrowth of tubular sprouts from the periphery of endothelial-cell-containing collagen discs. Conditioned medium from Swiss 3T3 cells mimicked the effect of co-culture by inducing formation of capillary-like tubes, and also increased plasminogen activator activity in endothelial cells. Conditioned medium from Balb 3T3 cells, in contrast, lacked these activities. Preliminary evidence suggests that the factor(s) in Swiss 3T3 conditioned medium that induces tubule formation by endothelial cells may be different from a number of well-characterized angiogenic cytokines. The co-culture systems described here should prove to be useful for the identification of physiological regulators of angiogenesis produced by various cell types.

This article has been cited by other articles:

				L. C. Armstrong, B. Bjorkblom, K. D. Hankenson, A. W. Siadak, C. E. Stiles, and P. Bornstein Thrombospondin 2 Inhibits Microvascular Endothelial Cell Proliferation by a Caspase-independent Mechanism Mol. Biol. Cell, June 1, 2002; 13(6): 1893 - 1905. [Abstract] [Full Text] [PDF]

				P. G. Phillips, L. M. Birnby, A. Narendran, and W. L. Milonovich Nitric oxide modulates capillary formation at the endothelial cell-tumor cell interface Am J Physiol Lung Cell Mol Physiol, July 1, 2001; 281(1): L278 - L290. [Abstract] [Full Text] [PDF]

				X. Xin, S. Yang, G. Ingle, C. Zlot, L. Rangell, J. Kowalski, R. Schwall, N. Ferrara, and M. E. Gerritsen Hepatocyte Growth Factor Enhances Vascular Endothelial Growth Factor-Induced Angiogenesis in Vitro and in Vivo Am. J. Pathol., March 1, 2001; 158(3): 1111 - 1120. [Abstract] [Full Text] [PDF]

				Q. Yu and I. Stamenkovic Cell surface-localized matrix metalloproteinase-9 proteolytically activates TGF-beta and promotes tumor invasion and angiogenesis Genes & Dev., January 15, 2000; 14(2): 163 - 176. [Abstract] [Full Text]

				D. H.-K. Ma, R. J.-F. Tsai, W.-K. Chu, C.-H. Kao, and J.-K. Chen Inhibition of Vascular Endothelial Cell Morphogenesis in Cultures by Limbal Epithelial Cells Invest. Ophthalmol. Vis. Sci., July 1, 1999; 40(8): 1822 - 1828. [Abstract] [Full Text] [PDF]

				A. F. Black, F. Berthod, N. L'heureux, L. Germain, and F. A. Auger In vitro reconstruction of a human capillary-like network in a tissue-engineered skin equivalent FASEB J, October 1, 1998; 12(13): 1331 - 1340. [Abstract] [Full Text]