"What this tells us is that stress might have a worse effect on melanoma that is in a very aggressive or advanced stage, and that one marker for that might be increased levels of IL-6," he said.
The researchers ruled out cell proliferation an increase in the number of cells present as a reason for the increase in all three proteins. That meant that the only other answer was that the cells were increasing their expression of the genes responsible for producing these compounds.
The researchers showed that the norepinephrine molecule binds to receptors on the surface of cancer cells and once this linkage occurs, it stimulates the release of the proteins that support angiogenesis and tumor growth.
Yang and Glaser first confirmed that the receptors were present on cells in all three cell lines and then tested what would happen when the receptors were blocked by common blood pressure medicine the so-called "beta-blockers."
When the beta-blockers did bind to the receptors, the production of the three proteins reduced significantly, suggesting that in patients with melanoma, using these types of medications might be used to slow the progression of the disease in patients.
While the study was restricted to tumor cell lines, rather than using animal models or human patients, the findings are still exciting. The researchers found strong evidence that the same receptors are expressed on the surface of tumor cells from biopsies that were taken from melanoma patients. That supports the clinical importance of the results.
Two earlier studies on different tumor cell lines one prepared from a multiple myeloma and the other from a nasopharyngeal carcinoma also showed that exposure to norepinephrine increased the levels of proteins responsible for accelerating tumor growth.'/>"/>
|Contact: Ronald Glaser|
Ohio State University