TGF-β signaling, activated stromal fibroblasts, and cysteine cathepsins B and L drive the invasive growth of human melanoma cells.
Accumulating evidence indicates that interactions between cancer cells and stromal cells are important for the development/progression of many cancers. Herein, we found that the invasive growth of melanoma cells in three-dimensional-Matrigel/collagen-I matrices is dramatically increased on their co-culture with embryonic or adult skin fibroblasts. Studies with fluorescent-labeled cells revealed that the melanoma cells first activate the fibroblasts, which then take the lead in invasion. To identify the physiologically relevant invasion-related proteases involved, we performed genome-wide microarray analyses of invasive human melanomas and benign nevi; we found up-regulation of cysteine cathepsins B and L, matrix metalloproteinase (MMP)-1 and -9, and urokinase- and tissue-type plasminogen activators. The mRNA levels of cathepsins B/L and plasminogen activators, but not MMPs, correlated with metastasis. The invasiveness/growth of the melanoma cells with fibroblasts was inhibited by cell membrane-permeable inhibitors of cathepsins B/L, but not by wide-spectrum inhibitors of MMPs. The IHC analysis of primary melanomas and benign nevi revealed cathepsin B to be predominantly expressed by melanoma cells and cathepsin L to be predominantly expressed by the tumor-associated fibroblasts surrounding the invading melanoma cells. Finally, cathepsin B regulated TGF-β production/signaling, which was required for the activation of fibroblasts and their promotion of the invasive growth of melanoma cells. These data provide a basis for testing inhibitors of TGF-β signaling and cathepsins B/L in the therapy of invasive/metastatic melanomas.
Department of Pathology, Haartman Institute, University of Helsinki and Helsinki University Central Hospital, Haartmaninkatu 3, Helsinki, Finland.
Miao
M
Yin
Johanna
J
Soikkeli
Tiina
T
Jahkola
Susanna
S
Virolainen
Olli
O
Saksela
Erkki
E
Hölttä
D000328:Adult; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D056668:Cathepsin L / Q000037:antagonists & inhibitors / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004622:Embryo, Mammalian / Q000473:pathology; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000473:pathology*; D005456:Fluorescent Dyes / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008545:Melanoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009506:Nevus / Q000201:enzymology / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D011480:Protease Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D017154:Stromal Cells / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D005456:Fluorescent Dyes; D011480:Protease Inhibitors; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C533912:CTSB protein, human; D002401:Cathepsin B; C534281:CTSL protein, human; D056668:Cathepsin L; D020782:Matrix Metalloproteinases