This is unexpected. Everyone thought that an errant cell took of and
spread by multiplying. How about simply converting neighbors as well
if not mostly. The way cancer does spread is quick and this trick
makes that process possible as well as its rapid spread in the body.
The hard question is to actually stop the process itself to also
stall the growth and spreading behavior in its tracks. Not as
satisfactory as an outright cure but it would still work very well in
saving lives.
In the meantime we have a major new research avenue.
Canadian scientists discover how
cancer cells communicate with healthy cells in major breakthrough
Sheryl Ubelacker,
Canadian Press | Dec 21, 2012
TORONTO — Canadian
scientists have made a major discovery about how cancer spreads:
tumour cells appear to co-opt normal cells around them, in effect
“talking” them into helping the cancer set up shop in other parts
of the body.
The process, called
metastasis, is what often makes malignancies so challenging to treat
— and typically more deadly.
“People often think
of cancer as this separate tissue, sort of like a foreign invader, a
thing that’s sitting inside that’s separate from their normal
body,” said principal investigator Jeff Wrana, a molecular
biologist at the Samuel Lunenfeld Research Institute in Toronto.
“But, in fact, the
cancers are intimately communicating in a dialogue with the normal
cells around them,” he said. “So basically, the normal cells are
passing signals to the tumour cells and the tumour cells are passing
signals to the normal cells.”
Working with human
breast cancer cells in the lab, Wrana and colleagues found that
tumour cells get sets of instructions in the form of protein
“messages” passed between healthy and cancerous cells.
It’s been known for
a while that communication existed between these cell types, but it
was thought it was akin to “words” or incomplete “sentences.”
‘We discovered that
the normal cells were basically sending an entire paragraph of
instructions to the tumour cells’
“But what we
discovered was that the normal cells were basically sending an entire
paragraph of instructions to the tumour cells,” said Wrana.
“And these
instructions were actually telling the tumour cells how to use its
own machinery to invade and metastasize, to spread throughout the
body.”
The protein that does
the talking is part of tiny fragments of cells called exosomes. In
cancer, the tumour cell releases exosomes to influence neighbouring
cells — and those nearby normal cells secrete exosomes that help
tumour cells to spread.
‘The tumour
cells are kind of tweaking the normal cells and making them
misbehave’
“The tumour cells
are kind of tweaking the normal cells and making them misbehave,”
explained Wrana. “Then these normal cells start producing things
that actually help the tumour cell.”
The researchers, who
were at first surprised and skeptical of their finding, also looked
for the phenomenon in lab mice bred as a model for human breast
cancer.
They found the
communication between normal and tumour cells also occurred in the
animals. And Wrana said the same process would go on in people.
Handout/Mount Sinai
Hospital/Canadian PressJeff Wrana, a molecular biologist at the
Samuel Lunenfeld Research Institute in Toronto, says members of his
research team were at first surprised and skeptical of their finding,
but also looked for the phenomenon in lab mice bred as a model for
human breast cancer. They found the communication between normal and
tumour cells also occurred in the animals. And Wrana said the same
process would go on in people.
“And it’s that
spreading metastases, for instance to the lung, that is the cause of
death for a vast number of cancer patients.”
Metastases that
originate from a primary cancer site in other organs — for
instance, a prostate tumour that transfers its cells into bone
—likely are activated in a similar way, said Wrana, whose lab will
next look for this cell-to-cell dialogue in invasive bladder cancer.
He said the discovery
of the exosomes’ role is important because it gives researchers a
new treatment target: “If we can interfere with that, then we can
block the ability of the cancer cells to spread out of the primary
site.”
The research team is
looking to develop drugs known as biologics that would block this
signal pathway between cells.
“Instead of only
targeting the primary tumour, we can now pinpoint the cells in the
tumour’s environment that are responding to the tumour and target
those too,” said Valbona Luga, a co-author of the study published
Thursday in the journal Cell.
“We hope to use our
new knowledge of the tumour’s immediate surroundings to intercept
its signals to cancer cells, and by doing so, drastically impede
tumour spreading,” she said.
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