TORONTO, Canada--Oncologists may someday have a powerful new gene
delivery tool to help in the war against cancer--a "gene
gun" that blasts pure DNA right inside tumor cells. The gun
was described at a media conference held in conjunction with the
American Association for Cancer Research meeting.
The size and shape of an ordinary pistol, the hand-held device
is pressed against the body. When fired, a burst of helium, compressed
at pressures up to 800 pounds per square inch, shoots millions
of microscopic DNA-coated gold pellets through the skin into the
tumor and surrounding cells. Traveling at near-supersonic speeds,
the particles can penetrate as many as 50 cell layers.
Because the gene-loaded particles pierce through cell walls, immune-stimulating
genes such as interleukin-2, interleukin-6, and gamma interferon
can be introduced into the cells. Once inside, they instruct the
cancer cells to produce and exude cytokine proteins, which, in
turn, attract white blood cells to the area to attack the rogue
In trials on mice with tumors transplanted under their skin, treatment
with the gene gun was found to slow down or even stop tumor growth,
said Dr. Ning-Sun Yang, PhD, of Agracetus Inc, the Wisconsin biotech
company that is developing the gun, known as Accell.
One quarter of the test mice became tumor-free, surviving more
than 60 days. "In the control group, all the untreated mice
were dead in 4 weeks," he said.
Dr. Yang believes that the gun may prove superior to the traditional
ways of administering gene therapy. "The device can insert
genes into the target cells in seconds," he said.
Because the gene gun uses brute force to deliver the material,
the genes can bypass the receptors that guard the target cells
and often block other gene delivery methods, Dr. Yang said.