Molecule Offers Cancer Imaging Applications

R&D Digest

The extreme accuracy of a molecule developed at Purdue University (West Lafayette, IN) has led researchers to draw comparisons to a homing device. Similar to the way a homing device guides a missile to its target, the Purdue molecule is able to lead imaging agents and drugs to prostate cancer cells.

According to a university release, the molecule “attaches to prostate-specific membrane antigen, or PSMA, a protein that is found on the membrane of more than 90% of prostate cancers.” The molecule is designed in a shape that fits to the PSMA, so that it can be carried inside the cell with the protein.
PSMA is also found on the blood vessels of most solid tumors, which could provide a way for the molecule to cut off a tumor's blood supply. “A lot of new drugs are being designed to destroy the vasculature of solid tumors,” says Philip Low, leader of the research team and the Ralph C. Corley Distinguished Professor of Biochemistry.
If these drugs could be attached to the molecule, he says, “We could not only kill the prostate cancer cells directly, we could also destroy the vasculature that feeds the tumor.”

The molecule's ability to directly target cancerous cells is important because it would eliminate many of the harmful side effects caused by current treatments. Those methods treat the entire body instead of just the tumor.

Another benefit of the molecule's targeting ability is that it would improve imaging of the disease. Researchers say a radioimaging agent can be linked to the targeting molecule and injected into cancer patients. Pictures can then be taken with a camera that detects radioactivity. Such images would help a doctor see whether the cancer has metastasized or spread to other parts of the body.
FDA has approved only one radioimaging agent for prostate cancer; but its large size makes its difficult to enter a solid tumor, Low says. The targeting molecule and radioimaging agent combination designed by the Purdue researchers is more than 150 times smaller than the existing agent, according to Low.
The radioimaging application created by the researchers is expected to enter clinical trials at the Indiana University Medical Center this fall. A separate application for the molecule—an optical imaging application that measures the prostate cancer cells in blood samples—is already in clinical trials.Copyright ©2009 Medical Device & Diagnostic Industry