Transcript Tumors and Blood Vessels By

Tumors and Blood Vessels
By:
Dimitri, Amy, Idil, Bianca
Questions:
How are tumors and blood vessels formed?
What is Angiogenesis?
How do tumors signal for angiogenesis to occur?
Do the blood vessels and tumors play a role in the metastasis
of cancer? If so how?
How are tumors formed?
• Cells reproduce uncontrollably
• Normal cells stop their division when it gets too
crowded, which is called density-dependent inhibition
• In cancer, the cells keep dividing to become an
abnormal tissue mass
How are blood vessels formed?
• Start off as small capillaries where blood travels
through
• The capillaries come together to form veins
• They are made of endothelial cells
What is angiogenesis?
What is angiogenesis?
• The process of forming new blood vessels from preexisting ones
• This process rarely occurs because the cells in the
blood vessels rarely divide
o During the creation of a child's circulatory system
o In the menstrual cycle of females
o In tissues during wound healing
• There are normally high amounts of inhibitor
molecules and low amounts of activator molecules
present in blood vessels which is why the cells do not
divide often
Steps in angiogenesis
• diseased or injured tissues produce and release angiogenic growth
factor signals
• Signals are sent from cells surface of endothelial cells to nucleus
and produces new molecules including enzymes
• Enzymes dissolve holes in the extracellular matrix then endothelial
cells grow and migrate out towards the tissue that sent the growth
factors
• specialized molecules called integrins that help pull the new blood
vessel forward
• additional enzymes that dissolve the tip of the growing blood
vessel and remold the tissue after extending
Steps in angiogenesis
• The blood vessels connect forming loops that allow for the
circulation of blood
• muscle cells stabilize the blood vessels, providing
structural support allowing for the blood to flow
How do tumors signal for angiogenesis
to occur?
How do tumors signal for angiogenesis
to occur?
tumor
cells release signal
molecules to normal
surrounding tissue that
activates certain genes in the
nucleus to make proteins that
encourage the growth of blood
vessels The vascular
endothelial growth factor and
basic fibroblast growth factor
are the two proteins that
are believed to be the most important in the whole
process of tumor growth
Role of blood vessels in metastasis of
cancer?
Blood vessels are the method
in which the cancer spreads.
The cancer goes into the
blood stream to the other
blood vessels that are
normal.
Blood vessels are how the
tumors actually stay
nourished because it
provides oxygen and
nutrients. This is how the
cancerous blood vessels are
able to remain effective in
cancer.
Further Questions:
What research has been/is being conducted on the
blood vessels of tumors?
Can angiogenesis inhibitors be used as treatment to
stop the growth of tumor cells or slow metastasis?
Sources:
http://www.sciencedaily.com/releases/2008/02/0
80219203539.htm http://wiki.answers.com/Q/Ho
w_do_tumors_form
http://greenfield.fortunecity.com/rattler/46/vess
els.htm
http://www.cancer.gov/cancertopics/understandi
ngcancer/angiogenesis
http://www.angio.org/understanding/process.php