Originally created 05/26/98

Experimental cancer drug administered with altered gene



WASHINGTON -- A protein that attacks cancer by blocking blood vessel formation can be administered using a modified gene contained in a non-infective virus, according to a French study involving laboratory mice.

In a study in the Proceedings of the National Academy of Sciences, French researchers report that they caused tumors in mice to shrink by injecting the animals with a gene for angiostatin, a protein that blocks formation of blood vessels. The study will be published on Tuesday.

The researchers reported that the gene, contained in a modified virus, "was shown to dramatically inhibit primary tumor growth" in laboratory mice that had been injected with both rat and human cancers.

Two drugs, angiostatin and endostatin, received wide publicity earlier this month when a researchers reported that injections of the compounds caused tumors in mice to shrink.

Instead of injecting the drug directly, the French researchers injected a virus that had been manipulated to include a gene for a key part of the angiostatin molecule. Inside the mice, the virus apparently infected the target tumors and then made the angiostatin. This blocked formation of blood vessels and caused the tumors to shrink, the researchers said.

However, the paper said that the experiment has been done only in laboratory mice. Such animal experiments often fail to have the same effect in humans.

The research was performed by scientists at the Gustave Roussy Institute in Villejuif, France, and the St. Louis Hospital in Paris.

Dr. Thomas N. Sato of the University of Texas, Southwestern Medical Center at Dallas, called the French study "a significant step toward specific and cost effective therapy to cure cancer," but he called for more research to improve the technique.