Metastatic outgrowth encompasses COL-I, FN1, and POSTN up-regulation and assembly to fibrillar networks regulating cell adhesion, migration, and growth.
Although the outgrowth of micrometastases into macrometastases is the rate-limiting step in metastatic progression and the main determinant of cancer fatality, the molecular mechanisms involved have been little studied. Here, we compared the gene expression profiles of melanoma lymph node micro- and macrometastases and unexpectedly found no common up-regulation of any single growth factor/cytokine, except for the cytokine-like SPP1. Importantly, metastatic outgrowth was found to be consistently associated with activation of the transforming growth factor-beta signaling pathway (confirmed by phospho-SMAD2 staining) and concerted up-regulation of POSTN, FN1, COL-I, and VCAN genes-all inducible by transforming growth factor-beta. The encoded extracellular matrix proteins were found to together form intricate fibrillar networks around tumor cell nests in melanoma and breast cancer metastases from various organs. Functional analyses suggested that these newly synthesized protein networks regulate adhesion, migration, and growth of tumor cells, fibroblasts, and endothelial cells. POSTN acted as an anti-adhesive molecule counteracting the adhesive functions of FN1 and COL-I. Further, cellular FN and POSTN were specifically overexpressed in the newly forming/formed tumor blood vessels. Transforming growth factor-beta receptors and the metastasis-related matrix proteins, POSTN and FN1, in particular, may thus provide attractive targets for development of new therapies against disseminated melanoma, breast cancer, and possibly other tumors, by affecting key processes of metastasis: tumor/stromal cell migration, growth, and angiogenesis.
Soikkeli
Johanna
J
Department of Pathology, Haartman Institute, P.O. Box 21 (Haartmaninkatu 3), FI-00014 Helsinki, Finland.
Podlasz
Piotr
P
Yin
Miao
M
Nummela
Pirjo
P
Jahkola
Tiina
T
Virolainen
Susanna
S
Krogerus
Leena
L
Heikkilä
Päivi
P
von Smitten
Karl
K
Saksela
Olli
O
Hölttä
Erkki
E
D002448:Cell Adhesion / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008207:Lymphatic Metastasis; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D046228:Microarray Analysis; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D053675:Versicans / Q000235:genetics / Q000378:metabolism
D015815:Cell Adhesion Molecules; D024042:Collagen Type I; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; C512835:POSTN protein, human; D053675:Versicans