2016 Report to Our Donors
It’s not a new idea that our immune system can kill cancer
cells. From 60 Minutes to CNN, the popular press is abuzz
with stories. Immunotherapy is quickly emerging as
the ‘fourth pillar’ of cancer treatment alongside surgery,
radiation and chemotherapy.
Researchers in the laboratories at Princess Margaret
Cancer Centre have been studying how to harness
the immune system for this purpose for many years.
Drs. Tak Mak and Pamela Ohashi are world leaders
in understanding the individual components of the
immune system and how they interact to generate an
immune response against something foreign to our body.
Today, under the leadership of Dr. Lillian Siu,
immunotherapy research is also being conducted in
our patient clinics. We have four Phase I/II clinical trials
underway, and will soon be recruiting patients for four
more trials. Our team is working on multiple strategies to
train, boost and engineer the immune system to be more
effective in recognizing and eradicating cancer. Multiple
strategies are required because each person’s cancer and
each person’s immune system are different.
Pumping up and
Two years ago, Dr. Ohashi and her team initiated a clinical
trial that harvests T-cells found within a patient’s tumor.
A specially-trained cell production team ‘manufactures’
more of these cells that are then transferred back to
the patient. By starting with T-cells that have already
recognized and infiltrated the tumor, Dr. Ohashi’s research
indicates this approach will generate a stronger and more
robust immune system attack against their cancer.
Another approach involves the natural ‘accelerators’ or ‘gas
pedals’ that can be activated to stimulate the immune
system to attack cancer cells.
At The Princess Margaret, several drugs are being tested
to take advantage of these ‘gas pedals’ and boost the
Making cancer cells look
One of the reasons the immune system doesn’t mount
an attack is because cancer cells look too much like the
healthy cells of our body. So some of the strategies our
researchers are pursuing involve making cancer appear
more foreign so the immune system will go into attack
mode. Infecting cancer cells with viruses or substances
that can mimic viruses helps the immune system
recognize and hone in on cancer cells.
Making the immune
system work harder
Our clinical researchers are testing new drugs that are
able to ‘take the brakes off’ the immune system. The
points at which the immune system applies ‘brakes’ to
slow down or stop the immune response are called the
‘checkpoints’, so this immunotherapy approach is referred
to as checkpoint inhibitor.
Our team is working on several different ways to engineer
or genetically modify T-cells so that they can more
effectively recognize, target and kill cancer cells.
Drs. Naoto Hirano and Marcus Butler have developed a
cell called an artificial antigen-presenting cell that will be
used in the laboratory to grow T-cells that can hone in on
cancer cells and kill them.
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