Cancer16BB

Cells leave the circulation and pass into the

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Unformatted text preview: on” 3. Cells leave the circulation and pass into the vascular Cells walls of vessels “Extravasation” walls – Motility factors produced by the tumor support cell Motility motility motility Tumor Spread Tumor Local Invasion Tumor Spread Tumor Autocrine Motility Factor Tumor Spread Tumor Local Invasion Lytic Enyzmes – Normal tissues surrounding tumors - matrix Normal degradation degradation » Mechanism may be due to tumor produced enzymes – Tumor cells have high levels of hydrolases - enzymes Tumor degrading proteins degrading » Proteases » Collagenases etc.. Tumor Spread Tumor Local Invasion Lytic enzymes (continued) – Proteases are inhibited by antiproteases present in normal cells » Tumor margins have enhanced protease levels relative to antiproteases – Tumor proteases - three classes identified » » » Serine Cysteine Matrix metalloproteinases (MMPs) – MMPs » Increased in epithelial cancers » Have a role in producing new blood vessels (angiogenesis) Tumor Spread Tumor Local Invasion Lytic enzymes (continued) – Highly metastatic tumors » Have high MMP (type IV) collagenase Cleave collagen of epithelial and vascular cells – Allow invasion from initial tumor to circulation » Inhibition of collagenase reduces metastases Tumor Spread Tumor Local Invasion Lytic enzymes (continued) – Urokinase type plasminogen activator (uPA) » Increased in tumor cells » uPA converts plasminogen (proenzyme) into protease uPA plasmin (active) plasmin Deg...
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This note was uploaded on 04/18/2013 for the course BIO 205 taught by Professor Dr.cady during the Spring '11 term at Bradley.

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