B lymphocyte-specific c-Myc expression stimulates early and functional expansion of the vasculature and lymphatics during lymphomagenesis.
Expression of the c-myc proto-oncogene is deregulated in many human cancers. We examined the role of c-Myc in stimulating angiogenesis and lymphangiogenesis in a highly metastatic murine model of Burkitt's lymphoma (E micro -c-myc), where c-Myc is expressed exclusively in B lymphocytes. Immunohistochemical analysis of bone marrow and lymph nodes from young (preneoplastic) E micro -c-myc transgenic mice revealed increased growth of blood vessels, which are functional by dye flow assay. Lymphatic sinuses also increased in size and number within the lymph nodes, as demonstrated by immunostaining for with a lymphatic endothelial marker 10.1.1. The 10.1.1 antibody recognizes VEGFR-2- and VEGFR-3-positive lymphatic sinuses and vessels within lymph nodes, and also recognizes lymphatic vessels in other tissues. Subcutaneously injected dye traveled more efficiently through draining lymph nodes in E micro -c-myc mice, indicating that these hypertrophic lymphatic sinuses increase lymph flow. Purified B lymphocytes and lymphoid tissues from E micro -c-myc mice expressed increased levels of vascular endothelial growth factor (VEGF) by immunohistochemical or immunoblot assays, which could promote blood and lymphatic vessel growth through interaction with VEGFR-2, which is expressed on the endothelium of both vessel types. These results indicate that constitutive c-Myc expression stimulates angiogenesis and lymphangiogenesis, which may promote the rapid growth and metastasis of c-Myc-expressing cancer cells, respectively.
Ruddell
Alanna
A
Fred Hutchinson Cancer Research Center, the Department of Biological Structure, and the Department of Comparative Medicine, University of Washington, Seattle, Washington 98109-1024, USA. aruddell@fred.fhcrc.org
Mezquita
Pau
P
Brandvold
Kimberly A
KA
Farr
Andrew
A
Iritani
Brian M
BM
D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D001775:Blood Circulation; D001853:Bone Marrow / Q000098:blood supply; D002051:Burkitt Lymphoma / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D004396:Coloring Agents; D008198:Lymph Nodes / Q000098:blood supply* / Q000473:pathology; D042583:Lymphangiogenesis; D051379:Mice; D008822:Mice, Transgenic; D009389:Neovascularization, Pathologic / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D004396:Coloring Agents; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc; D042461:Vascular Endothelial Growth Factor A