Lymphangiogenesis in development and human disease (2007)

In angiogenesis, permeability of blood vessels is regulated by vascular endothelial growth factor (VEGF) via its two receptors VEGFR-1 and VEGFR-2. The VEGFR-3 receptor does not bind VEGF and its expression becomes restricted mainly to lymphatic endothelia during development. We have found that homozygous VEGFR-3-targeted mice die around midgestation because of cardiovascular failure. We have also purified and cloned the VEGFR-3 ligand, VEGF-C. Transgenic mice expressing VEGF-C showed evidence of lymphangiogenesis, and VEGF-C knockout mice had defective lymphatic vessels. VEGF-C could be used to treat lymphedema, even in a genetic mouse model where VEGFR-3 is mutant (Milroy's disease). In contrast, in lymphedema disticiasis, FoxC2 transcription factor mutation led to defective valves and abnormal mural cell recruitment, resulting in lymphatic vascular failure. The proteolytically processed form of VEGF-C binds also to VEGFR-2 and is angiogenic. VEGF-D is closely related to VEGF-C, similarly processed and binds to the same receptors. Thus VEGF-C and VEGF-D appear to be both angiogenic and lymphangiogenic growth factors. VEGF-C overexpression induced lymphangiogenesis and growth of the draining lymphatic vessels, intralymphatic tumor growth and lymph node metastasis in several tumor models. Furthermore, soluble VEGFR-3, which blocked embryonic lymphangiogenesis, also blocked lymphatic metastasis in breast and lung cancer models. These results together with recent clinical cancer studies suggest that paracrine signal transduction between tumor cells and the lymphatic endothelium may be involved in lymphatic metastasis of human cancers. Alitalo K, Tammela T, Petrova TV. Lymphangiogenesis in development and human disease. Nature 2005: 438: 946–953. A review Tammela T, Petrova TV, Alitalo K. Molecular lymphangiogenesis: new players. Trends Cell Biol 2005: 15: 434–441. A review He Y, Rajantie I, Pajusola K, Jeltsch M, Holopainen T, Yla-Herttuala S, Harding T, Jooss K, Takahashi T, Alitalo K. Vascular endothelial cell growth factor receptor 3-mediated activation of lymphatic endothelium is crucial for tumor cell entry and spread via lymphatic vessels. Cancer Res 2005: 65: 4739–4746. The authors show the mechanism of VEGF-C-induced lymphatic sprouting towards as well as dilation of the draining lymphatic vessels, both contributing to lymphatic metastasis. These processes were blocked dose-dependently by inhibition of VEGFR-3. Karkkainen MJ, Haiko P, Sainio K, Partanen J, Taipale J, Petrova TV, Jeltsch M, Jackson DG, Talikka M, Rauvala H, Betsholtz C, Alitalo K. Vascular endothelial growth factor C is required for sprouting of the first lymphatic vessels from embryonic veins. Nat Immunol 2004: 5: 74–80. The results of this paper indicate that VEGF-C is the paracrine factor essential for lymphangiogenesis, and show that both Vegfc alleles are required for normal lymphatic development. He Y, Kozaki K, Karpanen T, Koshikawa K, Yla-Herttuala S, Takahashi T, Alitalo K. Suppression of tumor lymphangiogenesis and lymph node metastasis by blocking vascular endothelial growth factor receptor 3 signaling. J Natl Cancer Inst 2002: 94: 819–825. The authors use inhibition of VEGFR-3 signalling for suppression of tumor lymphangiogenesis and metastasis to regional lymph nodes. Mäkinen T, Jussila L, Veikkola T, Kärpänen T, Kettunen MI, Pulkkanen KJ, Kauppinen R, Jackson DG, Kubo H, Nishikawa S-I, Ylä-Herttuala S, Alitalo K. Inhibition of lymphangiogenesis with resulting lymphedema in transgenic mice expressing soluble VEGF receptor-3. Nat Med 2001: 7: 199–205. Shown here is that a soluble form of VEGFR-3 is a potent inhibitor of VEGF-C/VEGF-D signalling, and it inhibits lymphangiogenesis. Karpanen T, Egeblad M, Karkkainen MJ, Kubo H, Yla-Herttuala S, Jaattela M, Alitalo K. Vascular endothelial growth factor C promotes tumor lymphangiogenesis and intralymphatic tumor growth. Cancer Res 2001: 61: 1786–1790. These data show that VEGF-C facilitates tumor metastasis to the lymphatic vessels and that tumor spread can be inhibited by blocking the interaction between VEGF-C and its receptor. Mandriota SJ, Jussila L, Jeltsch M, Compagni A, Baetens D, Prevo R, Banerji S, Huarte J, Montesano R, Jackson DG, Orci L, Alitalo K, Christofori G, Pepper MS. Vascular endothelial growth factor-C-mediated lymphangiogenesis promotes tumour metastasis. EMBO J 2001: 20: 672–682. The findings demonstrate that VEGF-C-induced lymphangiogenesis mediates tumor cell dissemination and the formation of lymph node metastases. Karkkainen MJ, Saaristo A, Jussila L, Karila KA, Lawrence EC, Pajusola K, Bueler H, Eichmann A, Kauppinen R, Kettunen MI, Yla-Herttuala S, Finegold DN, Ferrell RE, Alitalo K. A model for gene therapy of human hereditary lymphedema. Proc Natl Acad Sci U S A 2001: 98: 12677–12682. A model to show that growth factor gene therapy would be applicable to human lymphedema and provide a paradigm for other diseases associated with mutant receptors. Alitalo K. VEGF family and lymphangiogenesis. In: Witte M. et al: Proceedings of the NIH Think Tank Conference Conquering Lymphatic Disease, Setting the Research Agenda Washington, May 11–13, 2000, The University of Arizona Press. The first publication indicating that VEGF-C expression in tumor cells enhances tumor metastasis to the lymph nodes. Karkkainen MJ, Ferrell RE, Lawrence EC, Kimak MA, Levinson KL, McTigue MA, Alitalo K, Finegold DN. Missense mutations interfere with VEGFR-3 signalling in primary lymphoedema. Nat Genet 2000: 25: 153–159. Heterozygous missense mutations of VEGFR-3 were shown to inactivate the tyrosine kinase and downstream gene activation in primary lymphedema, indicating that mutations interfering with VEGFR-3 signal transduction are a cause of primary lymphoedema. Dumont DJ, Jussila L, Taipale J, Lymboussaki A, Mustonen T, Pajusola K, Breitman M, Alitalo K. Cardiovascular failure in mouse embryos deficient in VEGF receptor-3. Science 1998: 282: 946–949. This paper shows that targeted inactivation of the Vegfr3 gene results in defective blood vessel development and cardiovascular failure. Thus, VEGFR-3 has an essential role in the development of the embryonic cardiovascular system before the emergence of the lymphatic vessels. Cao Y, Linden P, Farnebo J, Cao R, Eriksson A, Kumar V, Qi J-H, Claesson-Welsh L, Alitalo K. Vascular endothelial growth factor-C induces angiogenesis in vivo . Proc Natl Acad Sci U S A 1998: 95: 14389–14394. Demonstration of angiogenic activity of mature VEGF-C, suggesting that this factor could participate in the development and progression of angiogenic diseases in addition to lymphangiogenesis. Jeltsch M, Kaipainen A, Joukov V, Meng X, Lakso M, Rauvala H, Swartz M, Fukumura D, Rakesh KJ, Alitalo K. Hyperplasia of lymphatic vessels in VEGF-C transgenic mice. Science 1997: 276: 1423–1425. Transgenic overexpression of VEGF-C was found to induce lymphatic, but not vascular, endothelial proliferation and vessel growth. VEGF-C was predicted to play a role in disorders involving the lymphatic system. Joukov V, Sorsa T, Kumar V, Jeltsch M, Claesson-Welsh L, Cao Y, Saksela O, Kalkkinen N, Alitalo K. Proteolytic processing regulates receptor specificity and activity of VEGF-C. EMBO J 1997: 16: 3898–3911. Effects of posttranslational processing in VEGF-C secretion and function, as well as the structure of the mature VEGF-C. Kukk E, Lymboussaki A, Taira S, Kaipainen A, Jeltsch M, Joukov V, Alitalo K. VEGF-C receptor binding and pattern of expression with VEGFR-3 suggests a role in lymphatic vascular development. Development 1996: 122: 3829–3837. The pattern of expression of VEGF-C in relation to its major receptor VEGFR-3 during the sprouting of the lymphatic endothelium in embryos suggests a paracrine mode of action and that one of the functions of VEGF-C may be in the regulation of angiogenesis of the lymphatic vasculature. Joukov V, Pajusola K, Kaipainen A, Chilov D, Lahtinen I, Kukk E, Saksela O, Kalkkinen N, Alitalo K. A novel vascular endothelial growth factor, VEGF-C, is a ligand for the Flt4 (VEGFR-3) and KDR (VEGFR-2) receptor tyrosine kinases. EMBO J 1996: 15: 290–298. Purification and cloning of the VEGFR-3 ligand, VEGF-C, the first growth factor for lymphatic endothelia. Finding of proteolytic processing and binding to VEGFR-2. Kaipainen A, Korhonen J, Mustonen T, van Hinsbergh VWM, Fang G-H, Dumont D, Breitman M, Alitalo K. Expression of the fms-like tyrosine kinase 4 gene becomes restricted to lymphatic endothelium during development. Proc Natl Acad Sci U S A 1995: 92: 3566–3570. This article reported the novel finding that during mouse development the expression of the VEGFR-3 growth factor receptor gene becomes restricted to lymphatic endothelia. Increased expression occurred in metastatic lymph nodes and in lymphangioma. The results also suggested venous origin of the lymphatic vessels.