UCLA researchers might have overcome one of the major hurdles in
using gene therapy to treat cancer: the question of how to best
administer the treatment.
Gene therapies are currently administered to the body in a
variety of ways, such as intravenously ““ injecting genetic
material into the veins ““ or intralymphatically
““Â injecting it into the lymph nodes.
But getting the necessary material to the necessary location has
been a major obstacle.
Robert Suh, assistant clinical professor of radiology and
director of Thoracic Interventional Services at UCLA’s David
Geffen School of Medicine, devised a method to use computed
tomography imaging to pinpoint the exact location of the
cancer.
This will allow the genetic material to be directly introduced
into tumor cells.
CT imaging involves taking a 360 degree X-ray of the tissue or
organ in question.
“We’ve found a new way to deliver gene therapy
““ immune therapy ““ that can be done safely,” said
Suh.
Gene therapy is being used to treat cancer patients by altering
their DNA.
Under this approach, DNA is administered into the body along
with some type of transportation system, often a virus, which is
intended to bring the DNA into the cells.
Though there is a lot of promise in the use of Suh’s
CT-guided injection technique to administer gene therapy for
cancer, he does not expect it to be a magic bullet.
All cancers are different and respond differently to
treatments.
“Certain subsets of cancer may do very well with gene
therapy, but others might be treated more successfully with a
different approach,” Suh said.
Suh’s team studied a total of 29 patients and performed
284 CT-guided injections.
Although none of the patients had serious side effects, almost
15 percent experienced minor complications.
The use of gene therapy as a treatment has been considered for
many different types of cancer, but Suh’s research centered
on metastic kidney cancer, a type which is especially difficult to
treat.
Metastic cancer is cancer which spreads from its original
location.
Metastic kidney cancer is resistant to chemotherapy ““
which is intended to kill the cancer cells ““ and the one
treatment currently approved by the Food and Drug Administration
has a response rate of only 15 percent.
The FDA treatment involves intravenously injecting
interleukin-2, a particular protein which stimulates the immune
system. Suh’s approach involves interleukin-2 in a different
way.
Instead of injecting the protein directly, genetic material
coding for interleukin-2 is injected into the patients, hopefully
stimulating its production.
By injecting the genetic material directly into the most
problematic cells, rather than the entire body or even the general
vicinity of the tumor, the treatment is much more likely to
stimulate the necessary cells.
Though the genetic material must be developed individually for
different types of cancer, the administration technique can remain
uniform.
“If this type of delivery system, the injection technique,
is validated, you can come up with other genes for other tumors
that may be useful for treating cancer,” Suh said.
Vical, a biotechnology firm which funded the study, developed
the genetic material coding for interleukin-2.
Suh worked with other faculty members from the department of
radiology and the UCLA Jonsson Cancer Center.