Experimental Drug May Fight Pancreatic Cancer
Drug, Made from Shrub's Seeds, Hasn't Been Tested on People Yet
Aug. 18, 2005 -- An experimental drug made from the seeds of the croton shrub may help fight pancreatic cancer, a new study shows.
The drug is based on a compound called TPA that's found in oil made from the shrub's seeds. Don't confuse it with "tPA." That's a completely different drug, which is used as a clot buster for heart attack and stroke patients.
So far, TPA has been tested on human pancreatic cancer cells in the lab and on mice -- but not on people. In earlier experiments, TPA was shown to hinder human prostate cancer cells, write Allan Conney, PhD, and colleagues.
Conney's study appears online in The Journal of Pharmacology and Experimental Therapeutics.
No. 4 Cause of Cancer Deaths
Cancer of the pancreas is the fourth leading cause of U.S. cancer deaths, according to the American Cancer Society (ACS).
The ACS predicts that more than 32,000 people in the U.S. will be diagnosed with pancreatic cancer this year, and about 31,800 will die of the disease. Cancer of the pancreas is a very serious disease -- only about 1 in 25 patients will survive for one year or more, according to the ACS. Aside from advanced age, smoking is the main risk factor for pancreatic cancer; a smoker is three to four times more likely than a nonsmoker to get the disease. People frequently exposed to certain petroleum products may also be at increased risk. Excessive dietary fat and protein as well as low-fiber intake may promote the disease.
'Definitely Worth Pursuing'
"Pancreatic cancer is a tough one to treat. Treatment
TPA has good potential for therapy, so it's definitely worth pursuing," says Allan Conney, PhD, in a news release.
Conney worked on the TPA tests. He is a professor of chemical biology and the Garbe Professor of Cancer and Leukemia Research at Rutgers, the State University of New Jersey.
The lab studies used TPA doses that shouldn't be toxic to humans, note the researchers.
When tested with another drug called ATRA (all-trans retinoic acid), TPA fared even better.
"We found that the TPA/ATRA combination in cell culture worked better than the individual components alone," says Conney.
"We were simultaneously stopping the growth of new cancer cells and killing those already existing. This was most dramatic when we used the TPA/ATRA combination on the tumors," he continues.
The researchers write that their studies provide encouragement for a clinical trial to test the TPA and ATRA combination in prostate and pancreatic cancer patients.
"It is this TPA/ATRA combination, with its lower doses and its demonstrated synergy, that we would very dearly like to see move to human clinical trials," says Conney.