April 9, 2002
MEDIA CONTACT: Vanessa Wasta
SMART BOMB THERAPY FOR PROSTATE CANCER
Hopkins Kimmel Cancer Center researchers are exploring new ways to deliver targeted prostate cancer therapy by linking anti-cancer drugs to protein carriers that are activated by prostate specific antigen (PSA). When these so-called "pro-drugs" reach prostate tumors, PSA clips off the protein carrier freeing the drug to kill cancer cells. Pro-drugs may be most helpful in reaching prostate cancers that have spread to other parts of the body. PSA, produced only by prostate cells and prostate cancer cells, is shut down when it gets into the blood, but is found in high levels surrounding prostate tumors.
Researchers are testing PSA-based pro-drugs made with standard chemotherapy agents like taxol and 5-flourodeoxyuridine (5-FU) as well as new agents currently too toxic for patients if given systemically. One such drug is Thapsigargin, an extract from the seed of a Mediterranean plant in the carrot family, called Thapsia garganica L. Thapsigargin causes cell death by blocking a critical energy pump within the cell and, unlike many standard therapies, can kill prostate cancer cells that are not dividing rapidly. Animal studies by Hopkins Kimmel Cancer Center researchers show that PSA-based pro-drugs made with Thapsigargin destroy more than 80 percent of prostate cancer cells after two weeks of injections directly into the tumor.