Platelets are blood cells involved with clotting. They promote
the growth of cancerous cells by releasing growth factors and increasing the
response of certain proteins that regulate tumor cell development
(oncoproteins).
Low doses of aspirin, an anti-platelet drug, have been shown
to reduce the risk of some types of gastrointestinal cancers, but the process
by which aspirin hampers tumor growth has been unclear.
“The current study was designed to determine the effect of
inhibition of platelet activation and function by aspirin therapy on colon and
pancreatic cancer cell proliferation,” the researchers wrote.
The research team combined activated platelets primed for the clotting process with three groups of cancer cells:
• metastatic colon cancer (cells that have spread outside the colon),
• nonmetastatic colon cancer (cells that grow only within the colon) and
• nonmetastatic pancreatic cancer cells.
When they added aspirin to the mixture, they found that the
platelets were no longer able to stimulate growth and replication in the
pancreatic and nonmetastatic colon cancer cells.
The metastatic colon cancer cells continued to multiply when
treated with aspirin.
In pancreatic cancer cells, low doses of aspirin stopped the
platelets from releasing growth factor and hampered the signaling of the
oncoproteins that cause cancer to survive and spread.
Only very high doses—larger than are possible to take
orally—were effective in stopping growth in the metastatic colon cells,
explained the researchers.
The findings detail the interaction among platelets, aspirin
and tumor cells and are promising for the future treatment of nonmetastatic
cancer, according to the researchers.
“Our study reveals
important differences and specificities in the mechanism of action of high- and
low-dose aspirin in metastatic and nonmetastatic cancer cells with different
tumor origins and suggests that the ability of aspirin to prevent
platelet-induced c-MYC [an oncoprotein] expression might be selective for a
nonmetastatic phenotype.”
Physiology is the study of how molecules, cells,
tissues and organs function in health and disease. Established in 1887, the
American Physiological Society (APS) was the first U.S. society in the
biomedical sciences field. The Society represents more than 11,000 members and
publishes 14 peer-reviewed journals with a worldwide readership.
