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Source: ONE News -
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US researchers have found a chemical that can kill breast cancer
stem cells - a kind of master cancer cell that resists conventional
treatment and may explain why many cancers grow back.
Finding ways to destroy these cells could make cancer far easier to
cure.
"There is a lot of evidence to suggest now that these cells are
responsible for many of the recurrences that are observed after
treatment has stopped," Piyush Gupta of the Massachusetts Institute
of Technology and the Broad Institute, whose study appears in the
journal Cell, said.
The problem is that cancer stem cells are rare and difficult to
study in the lab because they quickly change into other types of
cells.
And they are hard to kill.
"It wasn't clear it would be possible to find compounds that
selectively kill cancer stem cells," Gupta said in a statement.
"That's what we did."
To study the cells, Gupta's team first devised a method for
stabilizing cancer stem cells in the lab and getting them to
multiply.
They then tested them against 16,000 natural and commercial
chemical compounds to see which ones were able to kill the cancer
stem cells specifically.
That turned up 32 contenders.
They narrowed down this list to a handful of chemicals, and tested
these in the lab and in mice.
A chemical called salinomycin hit the target.
It was 100 times more potent at killing breast cancer stem cells
than the common chemotherapy drug called paclitaxel or Taxol.
Cancer stem cells treated with salinomycin were far less able to
start breast cancers when injected into mice than cancer stem cells
treated by paclitaxel.
And the treatment also appeared to slow the growth of tumours in
the mice.
Gupta said it is not clear if salinomycin will emerge as the best
drug compound for killing breast cancer stem cells - or that it
will be safe to use in people with cancer.
But the study offers a new roadmap for drug companies to isolate
and test compounds capable of killing the cells.
"We now have an approach that can be used very systematically to
find such compounds," he said.
Ultimately, he said it may be possible to treat cancers with dual
therapies that wipe out the bulk of tumour cells and the
tumour-cell making machinery many conventional treatments leave
behind.
Cancer is the No 2 killer of Americans, with about 560,000 deaths
annually, topped only by heart disease, according to the American
Cancer Society.
