X-Message-Number: 14504
From: "George Smith" <>

Subject: News Release from UT Southwestern UT Southwestern researchers discover 
Date: Tue, 19 Sep 2000 15:37:42 -0700


UT Southwestern researchers discover protein that promotes cell death
Contact: Amy Shields
or e-mail: 

DALLAS - Sept. 11, 2000 - Researchers at UT Southwestern Medical Center at
Dallas have discovered that the protein SMAC may lead to the development of
drugs that eliminate cancerous cells. The protein, second
mitochondria-derived activator of caspases, promotes apoptosis, or cell

The results of the study appeared in the Aug. 24 issue of Nature.

Dr. Chunying Du, Howard Hughes Medical Institute fellow, Dr. Xiaodong Wang,
associate professor of biochemistry, and their colleagues previously
identified the protein by purifying it from large cultures of human cells.
The researchers noticed activity promoting the cell-death process and
discovered the protein located in the mitochondria of the cell. The findings
of this research appeared in the July 7 issue of Cell.

In their most recent study published in Nature, the researchers found that
SMAC appears to be the "master regulator" of apoptosis in mammals and is
ultimately responsible for cell death.

"It's a new protein that has never been found before," Wang said. "We know
how it works, its structure, and we know what part of the protein is doing
the job of apoptosis.

"The exciting part of this study is that out of the more than 200 amino
acids found in the protein, only seven are necessary to induce cell death.
It's very unusual to have such a very small part of the protein that can
carry out the function of apoptosis. This makes it possible for us to design
drugs based on the seven amino acids that will promote cell death in
cancerous cells."

A large presence of inhibitors of apoptosis (IAPs), a class of proteins, may
contribute to the resistance of cancer cells to chemotherapy, Du said. SMAC
may weaken the cancerous cells to chemotherapy, she said.

The long-term goal of the researchers is to replicate the protein and develo
p a drug that will kill cancerous cells.

Researchers at Princeton University assisted in identifying the actual
structure of the protein.

The Howard Hughes Medical Institute, the National Institutes of Health and
the Robert Welch Foundation funded the study.

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