A Division of Biochange, Unlimited
From the LA Times Sunday,
July 25, 1999
CUTTING EDGE / FRONTIERS: Four Fields That Have Been Shaped by, and Are Shaping Southern CA
BIOTECHNOLOGY
Developments in Genetic Engineering Continue at a Blistering Pace.
Some Cheer Researchers On; Others Would Slam on the Brakes.
By PAUL JACOBS
We're almost 50 years into the biotechnology age
and scientists still can't keep a lid on their
enthusiasm. Why should they? Why should
anyone? The newfound ability to decipher and
manipulate genes, spurred by the promise of profits,
has already resulted in developments that startle:
Bacteria produce human insulin and other hormones;
soybeans grow antibodies to the herpes virus; sheep
produce milk rich in blood-clotting proteins; crops
contain their own pesticides.
There are 79 biotech drugs on the market, and
hundreds more in various stages of testing--a fleet of
battleships being readied to head off forces already
beginning to kill and maim an aging baby boom
generation: cancer, heart disease, and brain disorders
such as Alzheimer's and Parkinson's. In the blooming
field of agricultural biotech, researchers are working on
a second wave of genetically engineered crops,
enriched with vitamins, proteins and heart-friendly fats.
Moreover, it no longer seems farfetched to suggest that
we'll soon test routinely for hundreds of genetic defects
and then fix the problem with the genetic equivalent of
duct tape: gene splicing. Researchers are injecting raw
genes into damaged heart muscle to reverse the effects of heart attacks
and
transplanting rejuvenated brain cells to replace defective circuitry. There
is even
talk of attacking aging itself, with enzymes to turn back that ever-ticking
biological clock.
So why, as we tip over the edge of the next millennium, do some practitioners
of the new science apologize--cooling their zeal with a breath of caution?
Why
do environmentalists talk of Frankencrops and Frankenfoods, and ethicists
fret
over efforts to smooth away human variability?
* * *
Don't talk to Bryon Vouga, 30, about the importance of the biotech revolution.
The Anaheim Hills high school teacher found out that his kidneys were failing
at
age 16, when he flunked a high school sports physical. Soon he was one
of
200,000 Americans who keep themselves alive by using dialysis to remove
impurities from their blood. Like most dialysis patients, Vouga also was
anemic
because his kidneys did not produce enough of a hormone called
erythropoietin, which stimulates the growth of red blood cells. He was
so
anemic, he recalls, that he'd drive his truck to Fullerton Community College,
then snooze under the camper shell and miss all of his classes.
His life changed in 1989, when Amgen, the Thousand Oaks biotech
company, began mass-producing a genetically engineered hormone under the
brand name Epogen. Vouga's still on dialysis, after two unsuccessful kidney
transplants and while waiting for a third. But he's now also an avid bicyclist.
Last
month he took off from Huntington Beach, heading for Jacksonville, Fla.,
on a
2,700-mile journey sponsored by the National Kidney Foundation, with the
backing of Amgen. If all goes well, he'll be finishing about now, after
stopping
three times a week for his regular dialysis.
* * *
The age of biotech was not born like the nuclear era, in a flash of light
followed by a mushroom cloud over a shaking desert. It began with a pair
of
junior researchers working in a lab in England in the early 1950s. There,
in a
brilliant flash of intellectual light, Englishman Francis Crick and American
James Watson figured out the structure of DNA, a long, thread-like molecule
already shown to be the chemical of heredity, the instruction manual for
most
living things.
"There's no question that the discovery set the stage for everything that
has
happened over the next 50 years," says Caltech President David Baltimore,
whose own biotech research won a Nobel Prize. "That discovery came out
of the
blue. It wasn't one of those things where there was lots of incremental
progress."
Watson and Crick discovered not just the architecture of a pretty
molecule--the spiraling staircase of the renowned double-helix--but that
the
structure explained how heredity worked on a molecular level, how the DNA
copies itself over and over as cells multiply.
It took from 1961 to 1965 to crack the genetic code, recalls Marshall
Nirenberg, chief of the laboratory of biochemical genetics at the National
Heart,
Lung and Blood Institute, and one of dozens of scientists who owe their
Nobel
prizes to work on genes. He and others figured out that the chemical building
blocks in DNA (adenosine, thymine, guanine and cytosine--identified as
the
letters A, T, G and C) were arranged in three-letter "words" along the
length of
the molecule, and that each word identified an amino acid to be moved into
place to form proteins, like adding so many beads to a string. "It became
really
obvious to me that you could program cells," said Nirenberg. Place fragments
of
DNA into them, "and the cells will follow the instructions," he says.
Over the next decade, scientists at Stanford University and UC San Francisco
found ways of doing just that: genetic engineering. It allowed production
of
human hormones like Epogen in fast-growing animal or bacterial cells.
Deciphering the DNA of disease-causing microbes led to the discovery of
new
targets for antibiotics and new sorts of vaccines. Decoding the DNA of
tumor
cells revealed defective genes responsible for the uncontrolled growth
that is
cancer. At least in theory, it seemed, damaged and mutated genes could
be
replaced with healthy ones, a process called gene therapy.
It sounded easy. USC's Dr. W. French Anderson knows better. He's spent
a
distinguished career preparing for the day when he can pluck a healthy
gene
from one individual and then slip millions of copies into the cells of
someone
suffering from a hereditary disease. In 1990, while at the National Institutes
of
Health in Maryland, Anderson was part of a team that made the first serious
attempt to do just that. The patients were girls, age 4 and 9, suffering
from a
rare genetic disorder that left them helpless to fight off infection. The
researchers removed white cells from the children, then treated the cells
with a
healthy gene that makes their missing enzyme, ADA.
Nine years later both are still alive and living normal lives. But Anderson
cannot say to what extent that is due to the gene therapy or to drug treatments
to
supply the enzyme.
A year ago, in a thoughtful review of 300 gene therapy experiments in 3,000
patients, Anderson concluded: "Except for anecdotal reports of individual
patients being helped, there is still no conclusive evidence that a gene-therapy
protocol has been successful in the treatment of a human disease." Talk
to
him, though, and he flashes the passionate certitude of a scientific evangelist:
"There's no doubt that gene therapy will revolutionize medicine over the
next
quarter century."
* * *
About one in every 2,500 caucasian children will be born with cystic fibrosis,
making it one of the most common inherited diseases. Researchers
discovered the gene responsible for this disease just a decade ago. Those
who carry a single copy of it have no symptoms. It's only when each parent
is a
carrier that there's a chance--one out of four--that a baby will be born
with the
disorder. Dr. Wayne Grody, professor of medical genetics at UCLA, conducted
one of the first mass screenings to identify carriers. He and a colleague
gently
brushed cells from the inside of the cheeks of 3,000 pregnant volunteers
at
UCLA and Kaiser Permanente clinics. Using techniques for multiplying and
checking the women's DNA, the team identified 55 carriers among the women,
but only one case in which both expectant parents carried the genetic defect.
For
reasons not yet understood, not all children born with defective cystic
fibrosis
genes develop the full-blown symptoms. Yet when the couple learned that
their
fetus had two defective genes, the woman terminated her pregnancy. Grody
believes that test and that option will soon be available to all women.
Dr. Leroy Hood talks about the day when doctors will check their patients'
genetic makeup as routinely as they reach for a thermometer. The University
of
Washington researcher's work is at the core of biotech's transformation
of
medicine. In the 1980s, while at Caltech, he and colleagues developed a
high-speed method for determining the order of the letters that represent
the
chemical building blocks of DNA. To read out the 3 billion letters contained
in a
normal set of human chromosomes, even scanning at 10 letters a second,
would take 10 years. But machines developed by Applied Biosystems, a
company that Hood helped establish, zip through the job.
By the year 2003, the federally sponsored Human Genome Project expects
to
finish a careful reading out of human DNA, with information on up to 100,000
genes--all but a few totally unknown today. Private companies say they
will do it
even sooner. "In 10, 15, 20 years, we'll know between 100 and 200 genes
that
cause many of the common diseases," Hood says. DNA "fingerprints" will
be
used to project a person's health.
organic farmers for decades have sprayed their fields with a bacterium,
Bacillus thuringiensis, or Bt, a microbe that produces natural pesticides.
After
identifying the genes that produce the toxins, scientists began splicing
them
into the crops, giving the genetically engineered plants an internal pesticide
supply. Quietly, these and other genetically modified plants have displaced
conventional ones, accounting for 50% of all soybeans in the United States
this
year and 30% of corn.
One of the first companies to put Bt into a crop and market the seeds was
Mycogen, a San Diego firm now part of Dow Chemical. The former CEO and
chairman of Mycogen, Jerry Caulder, remembers reading environmentalist
Rachel Carson's classic warning on the hazards of pesticide pollution.
He says
his company's early use of the Bt genes was an alternative to that scourge.
Such efforts were crude compared to a second wave of biotech plants under
development. "We want to use the plant's own natural defenses rather than
an
exotic gene like Bt," says Caulder, who heads Akkadix, a new, privately
held
biotech company.
Soon, he and others say, there will be crops that thrive on less fertilizer
and
water. And plants that produce oils with more of the good lipids that promote
a
healthy heart. And plants engineered to produce industrial chemicals, fibers
and pharmaceuticals. "Why not produce silk in soybeans?" asks Caulder.
* * *
Some worry about the accelerating pace of biotech discovery. Bacteria that
produce human insulin are fermented in carefully contained factories. But
the
Sierra Club's executive director, Carl Pope, is among those who have sounded
alarms about genetically modified plants, which take root wherever their
seeds
happen to land. Will they spread unchecked like weeds across the landscape,
or worse still, transfer pesticide resistance to create new breeds of superweeds
that will choke out desirable plants? And what about eating foods that
contain
their own engineered pesticides? So far, U.S. consumers seem unperturbed,
but many Europeans are wary of eating genetically modified foods, and several
large supermarket chains have raced to get them off grocery shelves.
Ethicists are repulsed by other possibilities for genetic manipulation.
Two
years ago, Scottish scientists revealed they had cloned the first
mammal--taking the DNA from an adult sheep and creating "Dolly." Suddenly,
human cloning--picture those Hitler clones in "The Boys From Brazil"--seemed
entirely feasible. Also troublesome is the recent work using "stem cells"
generated from human embryos and fetuses to refurbish damaged hearts and
brains.
More modest applications of the new technology have ethical implications
as
well. Human growth hormone is useful in treating children whose own bodies
don't produce enough. But what do you say to parents who see an advantage
to
their child's being two or three inches taller? Epogen has already been
used--misused, many say--to boost the red blood cell count, and thus the
energy, of competitive cyclists. And what about new drugs that might help
someone think more clearly? Says Alexander M. Capron, co-director of USC's
Pacific Center for Health Policy and Ethics: "One person's correction is
another
person's enhancement."
And the biotech revolution isn't giving us much time to weigh these issues.
- - -
Paul Jacobs Is a Times Staff Writer Who Covers Biotechnology