Snake Venom
could fight breast tumors

BOSTON, Aug 26 (Reuters)

A protein found in snake venom might work to fight breast cancer and perhaps other kinds of tumors, U.S. researchers said on Wednesday. They said the protein halted tumor growth on two fronts -- preventing tumor cells from spreading throughout the body and stopping them from growing tiny blood vessels to nourish themselves. "It has sort of a dual simultaneous action," Francis Markland, a biochemistry professor at the University of Southern California, said in a telephone interview. "It doesn't hurt the cells but suspends aspects of physiology."

Markland's team worked with copperhead venom and with specially-bred mice that had been injected with cells from human breast cancer tumors. Scientists first homed in on the proteins after noting that the victims of some snake bites bleed to death. They disrupt the action of another protein -- integrin -- on the surface of cells that helps them stick together. This makes them perfect as heart drugs, as they stop blood from clotting. But Markland thought this action might stop tumors from growing and spreading, too, as the integrins on tumor cells are similar to the ones on platelets. "Our hypothesis was that since they interacted with proteins on the surface of platelets, we reasoned that they would therefore interact with proteins on the surface of breast cancer cells," Markland said.