Bagaimana virus polio digunakan untuk lawan barah
A
technique developed several years ago at Duke University involving an
engineered hybrid of poliovirus and rhinovirus has shown great promise in
treating a lethal form of brain cancer. A new study released by the team has
described in detail how this modified virus both attacks tumor cells and
triggers the body's immune system to do the same, suggesting it could also
prove effective against other cancers.
Research
into recruiting viruses to become cancer-killing agents is booming at the
moment after recent genetic advances allowed scientists to effectively engineer
custom viruses. Recently, a team
discovered the Zika virus'remarkable ability to target and kill
glioblastomas, a form of brain cancer.
The
team at Duke University has pioneered development of a custom cancer-killing
virus, engineered as a hybrid of poliovirus and rhinovirus.
Back in
2014, researchers at Duke University published a breakthrough study showing how a
custom cancer-killing virus, called PVSRIPO, exhibits excitingly effective
results in killing cancer cells. This chimeric virus, engineered as a hybrid of
poliovirus and rhinovirus, was also shown to stimulate the immune system in
attacking tumors, thereby suppressing the cancer's nasty habit of remission.
Last
year, the FDA designated PVSRIPO as a "breakthrough therapy." This
designation, based on early clinical trial success, is designed to accelerate a
treatment's progress through the often time-consuming and laborious multi-phase
clinical approval process.
A new
study published by the researchers has, for the first time, elucidated how the
treatment works on a detailed level.
"We
have had a general understanding of how the modified poliovirus works, but not
the mechanistic details at this level," says Matthias Gromeier, the
study's co-senior author. "This is hugely important to us. Knowing the
steps that occur to generate an immune response will enable us to rationally
decide whether and what other therapies make sense in combination with
poliovirus to improve patient survival."
The
modified virus begins its attack by tracking down a protein called CD155, which
has been found in abundance on tumor cells. In this stage of the attack the
virus kills some, but not all, tumor cells. The virus also infects
antigen-presenting cells, including dendritic cells and macrophages. It is this
action that stimulates the body's immune system to attack, with cancer-killing
T-cells launching to knock out the poliovirus-infected tumor.
"Not
only is poliovirus killing tumor cells, it is also infecting the
antigen-presenting cells, which allows them to function in such a way that they
can now raise a T-cell response that can recognize and infiltrate a
tumor," says Smita Nair, co-senior author on the study with Grimier.
"This is an encouraging finding, because it means the poliovirus
stimulates an innate inflammatory response."
While
these initial studies are focusing on gliomas, a common type of brain tumor,
the technique should be transferrable to several other cancers across the human
body as the CD155 protein is a common marker across many cancer types.
"Because
PVSRIPO naturally targets and destroys cancer cells from most common cancer
types (pancreas, prostate, lung, colon, and many others), it can be directed
against these cancers as well," says Gromeier. "To establish this in
the clinic, we plan future clinical trials in patients with cancers other than
brain tumors."
The
team is continuing clinical trials examining the efficacy of the treatment and
undertaking further study looking into how the immune system responds to the
engineered virus.
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