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New Method Targets Tumors
While scientists have known about
tumor acidity for years, they had
not devised a way to target it –
until now; © NCI
It is possible, says biophysicist Oleg Andreev, that one day their detection method could be used as a universal procedure, similar to mammography or colonoscopies. Their harmless imaging test could locate a problem before the patient ever feels ill.
The key lies in the acidity level of cells. While normal cells maintain a pH of 7.4 with little variation, cancer cells expend a great deal of energy as they rapidly proliferate, pumping protons outside and creating an extracellular pH level of 5.5 to 6.5.
Donald Engelman at Yale University discovered that the so called pHLIP peptide targets acidity. Andreev and his URI colleague Yana Reshetnyak demonstrated this peptide could find a tumor in a mouse and deliver imaging or therapeutic agents specifically to cancer cells. The targeting system has a patent pending in the U.S. and Europe.
The researchers suggest their discovery method could be used to monitor other disease development and treatment. It also could play an important role in the study of arthritis, inflammation, infection, infraction, and stroke since those conditions also produce high acidity.
In addition to targeting cancerous tumors, the research couple has discovered a novel delivery agent, a molecular nanosyringe, which can deliver and inject diagnostic or therapeutic agents specifically to cancer cells.
"Since we know the mechanism of delivery and translocation, we believe that we are able to tune the nanosyringe properties and engineer a novel class of therapeutic and diagnostic agents," says Reshetnyak.
In a project with the Cancer Center at Rhode Island Hospital, the URI researchers have successfully shown that the peptide can deliver nanogold particles into the cancerous tumor. Once in place, the tiny gold particles can absorb more radiation, providing a more lethal dose to the tumor, but not to surrounding health cells.
MEDICA.de; Source: The University of Rhode Island