Some Tumors Contain Factors That May Block Metastasis
Note: Tyrosine, an amino acid, which can also be synthesized in the body from phenylalanine, is found in many high-protein food products such as soy products, chicken, turkey, fish, peanuts, almonds, avocados, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds. Tyrosine can also be obtained through supplementation.
ScienceDaily (Nov. 14, 2011) — Scientists are another step closer to understanding what drives tumor metastasis, as laboratory models suggest there are factors inside tumors that can slow their own growth.
In a recent issue of Cancer Research, a journal of the American Association for Cancer Research, Raúl A. Ruggiero, Ph.D., a biological researcher at the division of experimental medicine at the National Academy of Medicine in Buenos Aires, Argentina, described this novel mechanism.
Ruggiero and colleagues used bioanalytical methods of ion electrospray mass and tandem mass spectrometry to identify the factors that lead to metastasis resistance in laboratory models of localized cancer, a phenomenon called "concomitant tumor resistance" in which factors in a tumor can inhibit its own metastasis.
"The main cause of death in cancer patients is associated much more with metastasis rather than with the growth of a localized tumor, which generally can be surgically removed," he said.
Ruggiero's laboratory found that the presence of variant forms of the amino acid tyrosine were responsible for concomitant tumor resistance. In tumor models where these variants of tyrosine were present, the localized tumor did not tend to metastasize as fast as tumors lacking the variants.
Currently, tumor metastasis is treated with various chemotherapy regimens, but Ruggiero said the results of this sort of treatment are usually disappointing. He hopes that these tyrosine variants could be developed as a simple and safe type of therapy to retard metastatic growth.
"Both meta- and ortho-tyrosine have many attractive features. They exert antitumor effects at very low concentrations, are naturally produced in the proper tumor bearing organism, and do not appear to exert any toxic side effects," said Ruggiero. "If these findings are confirmed we could develop new and more harmless means to manage malignant disease."
In a breakthrough development, the Israeli company Vaxil BioTherapeutics has formulated a therapeutic cancer vaccine, now in clinical trials at Hadassah University Medical Center in Jerusalem. If all goes well, the vaccine could be available about six years down the road, to administer on a regular basis not only to help treat cancer but in order to keep the disease from recurring.
A traditional vaccine helps the body’s immune system fend off foreign invaders such as bacteria or viruses, and is administered to people who have not yet had the ailment. Therapeutic vaccines, like the one Vaxil has developed, are given to sick people, and work more like a drug.
Based in Ness Ziona, Vaxil was founded in 2006 by Dr. Lior Carmon, a biotechnology entrepreneur with a doctorate in immunology from the Weizmann Institute of Science in Rehovot. In June, Vaxil signed a memorandum of understanding to merge its activities into Sheldonco, a company traded on the Tel Aviv Stock Exchange.