Scientists have revealed that a key molecule in breast and lung
cancer cells can help switch off the cancers' ability to spread
around the body.
The findings by researchers at Imperial College London may help
scientists develop treatments that prevent cancer travelling around
the body - or produce some kind of test that allows doctors to
gauge how likely a cancer is to spread.
During tumour growth, cancer cells can break off and travel in
the bloodstream or lymph system to other parts of the body, in a
process called metastasis.
Patients whose cancers spread tend to have a worse prognosis,
explains Professor Justin Stebbing, from the Department of Surgery
and Cancer at Imperial: "The ability of a cancer to spread around
the body has a large impact on a
patient's survival. However, at the moment we are still in the
dark about why some cancers spread around the body - while others
stay in one place. This study has given important insights into
this process."
The researchers were looking at breast and lung cancer cells and
they found that a protein called MARK4 enables the cells to break
free and move around to other parts of the body, such as the brain
and liver. Although scientist are still unsure how it does this,
one theory is it affects the cell's internal scaffolding, enabling
it to move more easily around the body.
The team found that a molecule called miR-515-5p helps to
silence, or switch off, the gene that produces MARK4.
In the study, the team used human breast cancer and lung cancer
cells to show that the miR-515-5p molecule silences the gene MARK4.
They then confirmed this in mouse models, which showed that
increasing the amount of miR-515-5p prevents the spread of cancer
cells. The findings also revealed that the silencer molecule was
found in lower levels in human tumours that had spread around the
body.
The team then also established that patients with breast and
lung cancers whose tumours had low amounts of these silencer
molecules - or high amounts of MARK4 - had lower survival
rates.
Researchers are now investigating whether either the MARK4 gene
or the silencer molecule could be targeted with drugs. They are
also investigating whether these molecules could be used to develop
a test to indicate whether a patient's cancer is likely to
spread.
Professor Stebbing said: "In our work we have shown that this
silencer molecule is important in the spread of cancer. This is
very early stage research, so we now need
more studies to find out more about this molecule, and if it is
present in other types of cancer."
Dr Olivier Pardo, also from the Department of Surgery and Cancer
at Imperial, added: "Our work also identified that MARK4 enables
breast and lung cancer cells to both divide and invade other parts
of the body. These findings could have profound implications for
treating breast and lung cancers, two of the biggest cancer killers
worldwide." The paper, miR-515-5p controls cancer
cell migration through MARK4 regulation, is published inEMBO Reports.