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 pre-existing ones

•  This process rarely occurs because the cells in the blood vessels rarely divideo During the creation of a child's circulatory

systemo In the menstrual cycle of femaleso 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?

http://www.sciencedaily.com/releases/2008/02/080219203539.htm http://wiki.answers.com/Q/How_do_tumors_form

http://greenfield.fortunecity.com/rattler/46/vessels.htm

 http://www.cancer.gov/cancertopics/understandingcancer/angiogenesis

 http://www.angio.org/understanding/process.php

Sources: