2 proteins found, may curb tumors

Human Genome, UCLA announce discovery of blood vessel inhibitors

`We are very excited'

Aim is to produce drug that cuts off cancer's blood supply

August 06, 1999|By Mark Guidera | Mark Guidera,SUN STAFF

Researchers at Human Genome Sciences Inc. and the University of California at Los Angeles said yesterday that they have discovered two human proteins that might be used to block tumor growth.

The scientists warned, though, that the research on the proteins is still at a very early stage.

"We are very excited about this, but it's important to temper that with a realization that there is a lot more research that must be done," said Luisa Iruela-Arispe, a molecular biologist and assistant professor at UCLA. She headed a group of scientists that made the discovery.

"We are not announcing a cure for cancer by any means," she said.

The proteins inhibit what is known as angiogenesis, or blood vessel growth. Tumors grow blood vessels for nutrition so they can grow and spread.

Research into that field has blossomed in the past several years, and a number of biotechnology and pharmaceutical companies are pursuing drugs that may kill or inhibit cancers by blocking the blood flow that enables them to grow.

About a dozen experimental angiogenesis inhibitors are in development. ImmClone Therapeutics Inc. of New York, for example, has one in early human testing.

Craig Rosen, senior vice president for research and development at Human Genome, said the company plans to further study the two proteins before making a decision on whether it will attempt to develop a cancer treatment based on them.

Human Genome, based in Rockville, holds the commercial rights to both proteins, said Kate De Santis, a company spokeswoman.

The company has clinical trials under way on two protein-based drugs, one that helps heal wounds and the other that helps protect blood cells during chemotherapy.

A third Human Genome drug in clinical trials is based on a gene that stimulates new blood vessel growth for the treatment of heart disease. The drug is being co-developed by privately held Vascular Genetics Inc. Shares in Human Genome rose $1.6875 yesterday to close at $56.5625.

The UCLA/Human Genome team will disclose details of the two proteins today on the Web site of the Journal of Biological Chemistry, www.jbc.org. It will also publish a paper on the research in the Aug. 13 issue of the journal.

Iruela-Arispe said the two proteins, METH-1 and METH-2, were better at suppressing tumor growth in laboratory studies than endostatin, a widely studied family of naturally occurring proteins that block tumors by inhibiting blood vessel growth.

Another Rockville firm, EntreMed Inc., has developed an anti-cancer drug from an endostatin protein that was discovered by angiogenesis pioneer M. Judah Folkman of Children's Hospital in Boston. The company plans to begin much anticipated clinical trials of the experimental anti-tumor drug in September.

Iruela-Arispe, who has conducted angiogenesis research for a decade, said METH-1 and METH-2 were discovered using Human Genome's library of active proteins in human tissues. Genes trigger the production of proteins, which perform a wide range of important tasks in the body.

The researchers found that METH-1 and METH-2 blocked vascular growth in two commonly used laboratory tests that gauge blood vessel development.

"It's a big leap right now to say that the same thing will happen in animals or humans with tumors, but we are pretty sure it is likely that will happen," said Iruela-Arispe.

The scientist foresees tumor suppressors being used in combination with traditional cancer therapies, such as chemotherapy and radiation, rather than being used alone.

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