In laboratory studies, Johns Hopkins researchers say they
have found that stem cells from a patient's own fat may have the potential to
deliver new treatments directly into the brain after the surgical removal of a
glioblastoma, the most common and aggressive form of brain tumour.
The investigators say so-called mesenchymal stem cells
(MSCs) have an unexplained ability to seek out damaged cells, such as those
involved in cancer, and may provide clinicians a new tool for accessing
difficult-to-reach parts of the brain where cancer cells can hide and proliferate
anew. The researchers say harvesting MSCs from fat is less invasive and less
expensive than getting them from bone marrow, a more commonly studied method.
Results of the Johns Hopkins proof-of-principle study are
described online in the journal PLOS ONE.
How the study was
"The biggest challenge in brain cancer is the migration
of cancer cells. Even when we remove the tumor, some of the cells have already
slipped away and are causing damage somewhere else," says study leader
Alfredo Quinones-Hinojosa, M.D., a professor of neurosurgery, oncology and
neuroscience at the Johns Hopkins University School of Medicine.
"Building off our findings, we may be able to find a
way to arm a patient's own healthy cells with the treatment needed to chase
down those cancer cells and destroy them. It's truly personalised
For their test-tube experiments, Quinones-Hinojosa and his
colleagues bought human MSCs derived from both fat and bone marrow, and also
isolated and grew their own stem cell lines from fat removed from two patients.
Comparing the three cell lines, they discovered that all proliferated,
migrated, stayed alive and kept their potential as stem cells equally well.
This was an important finding, Quinones-Hinojosa says,
because it suggests that a patient's own fat cells might work as well as any to
create cancer-fighting cells. The MSCs, with their ability to home in on cancer
cells, might be able to act as a delivery mechanism, bringing drugs,
nanoparticles or some other treatment directly to the cells. Quinones-Hinojosa cautions
that while further studies are under way, it will be years before human trials
of MSC delivery systems can begin.
Ideally, he says, if MSCs work, a patient with a
glioblastoma would have some adipose tissue (fat) removed — from any number of
locations in the body — a short time before surgery. The MSCs in the fat would
be drawn out and manipulated in the lab to carry drugs or other treatments.
Then, after surgeons removed the brain tumor, they could deposit these
treatment-armed cells into the brain in the hopes that they would seek out and
destroy the cancer cells.
Survival not good
with current treatments
Currently, standard treatments for glioblastoma are
chemotherapy, radiation and surgery, but even a combination of all three rarely
leads to more than 18 months of survival after diagnosis. Glioblastoma tumour
cells are particularly nimble, migrating across the entire brain and
establishing new tumours. This migratory capability is thought to be a key
reason for the low cure rate of this tumour type.
"Essentially these MSCs are like a 'smart' device that
can track cancer cells," Quinones-Hinojosa says.
Quinones-Hinojosa says it's unclear why MSCs are attracted
to glioblastoma cells, but they appear to have a natural affinity for sites of
damage in the body, such as a wound. MSCs, whether derived from bone marrow or
fat, have been studied in animal models to treat trauma, Parkinson's disease,
ALS and other diseases.