Requirement for specific proteases in cancer cell intravasation as revealed by a novel semiquantitative PCR-based assay.
Proteases are crucial for cancer metastasis, but due to lack of assays, their role in intravasation has not yet been tested. We have developed a human Alu sequence PCR-based assay to quantitate intravasated cells in an in vivo model. We demonstrated that metalloproteinases (MMPs), and most likely MMP-9, are required for intravasation by showing that marimastat, an inhibitor of MMPs, reduced intravasation by more than 90%, and that only tumor cell lines expressing MMP-9 intravasated. Cells with low surface urokinase plasminogen activator (uPA) and uPA receptor (uPAR) were also incapable of intravasation, despite the presence of high levels of MMP-9. We concluded that breaching of the vascular wall is a rate-limiting step for intravasation, and consequently for metastasis, and that cooperation between uPA/uPAR and MMP-9 is required to complete this step.
Mount Sinai School of Medicine, Division of Neoplastic Diseases, New York, New York 10029, USA.
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Kim
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Yu
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Kovalski
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Ossowski
D000482:Allantois; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology / Q000473:pathology; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D002642:Chick Embryo; D002823:Chorion; D010450:Endopeptidases / Q000502:physiology*; D005260:Female; D006801:Humans; D006868:Hydrolysis; D008297:Male; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000473:pathology*; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured; D019043:Vascular Neoplasms / Q000201:enzymology / Q000473:pathology
D010450:Endopeptidases