We now are testing this compound against cancers in rats, and given positive results, we hope to begin clinical trials of this agent within two years. Specifically, Cpd 5 blocks the activity of enzymes called protein-tyrosine phosphatases, which normally remove phosphate groups from selected proteins inside liver cancer cells. However, Cpd 5 does not interfere with another group of enzymes called protein tyrosine-kinases, which add phosphate groups to these same proteins. The result is an excess of what are called tyrosine phosphorylated proteins, which trigger a variety of activities within cells. They exert anti-cancer effects by inducing the shutdown and subsequent death of a cell, commonly referred to as programmed cell death.
Liver cancer is thought to be one of the three commonest cancers worldwide.
The disease caused about 15,000 U.S. deaths in 1997 alone. Major causes of this cancer include infection with either hepatitis B or C or chronic alcohol consumption. In the United States and other developed countries, liver cancer may be treated by taking out the area of the liver containing a tumor or by surgically removing the diseased organ and transplanting a new one. However, liver transplantation is costly and often unavailable due to the scarcity of donated organs, or due to the advanced nature of the cancer at diagnosis. By providing this modified vitamin K to individuals at known risk of developing liver cancer, we might be able to reduce the incidence of this devastating illness.