Technology Gives Glimpse Into Genetics of Heart Attacks, Cancer
April 28, 2000 -- When the Human Genome Project is completed, scientists
will have, for the first time, the complete set of instructions for how to make
a human being. But once they've collected all 3.2 billion bits of information,
give or take a few hundred thousand, what will they do with it?
One group of scientists in California is using new technology that can scan
up to 30,000 genes at the same time to figure out whether there are changes in
the way that heart tissues recover from damage caused by a heart attack or
caused by chronic high blood pressure. Investigators can then follow up on
promising leads with more specific laboratory techniques. The information could
one day help researchers design better heart drugs, develop new treatments for
high blood pressure, and find better ways to identify people who are at risk
for having heart attacks.
Other researchers in Florida are using the same technology, called DNA
microarray sequencing, to scan the thousands of genes that constitute a cancer
cell. They also hope to find information that will aid accurate diagnosis of
cancer and improve cancer treatments.
The microarray technology works "like a new kind of microscope,"
allowing researchers to view the specific set of genes that each cell expresses
according to its precisely controlled "genetic script," writes Patrick
O. Brown, PhD, MD, associate professor of biochemistry at Stanford University,
on his laboratory's web site. This script gives each cell its distinctive
design and functional capabilities.
David G. Lowe, PhD, and colleagues from the biotechnology firm Genenetch
Inc., in South San Francisco, report in the heart journal Circulation on
their use of DNA microarray sequencing to study heart tissue in animals.
They found evidence to suggest that following a heart attack or other type
of heart damage, genes that had been active when the heart was developing in
the growing fetus, but then shut down, become re-activated in the adult heart.
If this is true, it may explain why some people who suffer heart attacks or
have high blood pressure suffer from cardiac hypertrophy, a condition in which
the heart becomes enlarged in order to compensate for the extra work it is
called on to do.
Although cardiac hypertrophy is considered a way for the heart to adapt to
illness -- it also puts the heart at greatly increased risk for failure.
Lowe and colleagues got a glimpse of the changes that the heart undergoes,
both during fetal development and following a heart attack, by using the
microarray technology to take a snapshot of hundreds or thousands of genes at
the same time.
They found that 12 genes that are known to be associated with heart
development were active in the sample of growing heart tissue. But they also
found 10 unidentified sections of DNA that could be new genes and identified 36
genes that had not previously been associated with heart development.