Studies have also revealed that bone acts as a reservoir for dormant cancer cells that, when awakened, cause new active growing cancers that are very difficult to cure, devastating fractures and dramatically worsen the prognosis of cancer patients.
‘Once a cancer spreads to bone, it becomes notoriously difficult to treat,’ said Professor Peter Croucher, Head, Bone Biology Division. ‘There are a great many dormant cells, yet only some of them are activated, and those that are, become activated at different times. So, it’s important to establish exactly what activates those cells in bone. Is it some signal within the cells themselves, or is it a change in their environment?
‘Our research has shown that the bone’s own dynamic process of building up and breaking down bone can send signals to cancer cells inside it, to stay dormant or become active. This has led us to think in a whole new way about treating bone metastasis – and there are two particularly promising treatment approaches.
‘The first is that we could inhibit the breakdown of bone, so as to keep cancer cells in long-term hibernation. In fact, there are already drugs that can do this, such as bisphosphonates (used to protect bone in individuals with osteoporosis), and there’s already evidence that these drugs do improve survival in breast cancer patients.
‘The other, more radical, option is to do the opposite – to wake the sleeping cells by activating the breakdown of bone. Most cancer treatments target active, dividing cells, so waking the sleeping cells should make them susceptible to those therapies – and, ultimately, could eradicate any residual disease.
‘We are now testing these ideas and hope to see them translated into the clinic in the near future. In addition, we have developed some new methods to work out the genes that control these rare dormant cells in bone. We are now looking to block the actions of these genes in order to stop them hibernating in the skeleton.’