Project 1 - Lecture Part 2
Friday, April 21, 2017 10:44 AM
• If tumor cells want to divide in order for the tumor to grow, it needs space to
enlarge into; the ECM gets in the way. If it wants to split of and potentially
metastasize, then it needs the ECM to give wayand allow the cell to migrate.
• Proteins in the ECM: collagen, laminin, proteoglycans, fibronectin
• MMP2 helps a tumor cell do what? They are made inside the cell, secreted and
used to modify the extracellular matrix. MMP2 is not found in general purpose
cells. In adults, it is mostly found in the environment of tumors.
• Why do we see MMP2 production around tumor cells? It would be beneficial
for a tumor cell to be able to modify its ECM to make room for growth and
• If MMP2 is eliminated from cells tumor paint still binds. MMPs can have their
production turned up based on growth factors, the need for cells to migrate and
grow. They help these processes by degrading the ECM.
• When the ECMchanges, it can bind to integral membrane proteins that can
communicate those changes to the inside of cells.
• Annexin binds to many things including proteoglycans, glycoproteins, tissue
plasminogen activators and collagen. Annexin can move in and out of cells
under regulated circumstances.
• A hypothesis is that annexin is found at higher levels outside of tumor cells.
• Annexin binds to tissue plasminogen activator (tPA), which is useful for
breaking up plasminogen into a more dissolved form called plasmin.
à helps activate MMPs
(perhaps annexin is turned up in cells that want to manufacture more
MMPs- whenthey need to grow tumors or move cells)
• DAPI: stains nucleus (blue)
• Isolectin: a protein that is found on blood vessel walls on epithelial cells.
• Blood vessels will not be as present (upregulated) in annexin A2loss of
function genotypes. Less annexin A2 = less isolectin : not very much