Could an osteoporosis drug turn off high-risk cells before they develop into cancer?
By Kemal Atlay
Australian scientists have discovered that an existing medication used to treat osteoporosis could be repurposed for cancer prevention and could spell hope for women at high risk of breast cancer, according to a new study.
Researchers from the Walter and Eliza Hall Institute of Medical Research found that the drug denosumab can target a group of breast tissue cells that are more prone to become cancerous in women who carry the faulty BRCA1 gene and prevent breast cancer development altogether. The study was published today in Nature Medicine.
“What our findings indicate or offer is a promising new strategy to prevent or delay breast cancers arising in women that carry a faulty BRCA1 gene,” Professor Jane Visvader, breast cancer expert and one of the lead researchers of the study, tells SBS.
“We’re very encouraged by these findings,” she says.
The researchers used breast tissue samples donated by women carrying the faulty BRCA1 gene to pinpoint a specific group of cells – they were highly proliferative, meaning they were dividing more than normal, and accumulated genetic errors - that were primed to become cancerous.
The also found these cells presented a protein marker called RANK and found that by blocking its actions with denosumab, they could delay or stop them from developing into cancerous cells.
“Now interestingly, we were able to target this molecule using an existing drug and we found that by targeting or blocking this molecule, we could switch off the proliferation of these rogue cells and even prevent or delay breast cancer development in pre-clinical laboratory models,” says Prof Visvader.
Although denosumab is not currently approved for breast cancer prevention, the researchers have described it as the ‘holy grail’ for their field as it presents the opportunity to ‘turn off’ these cells before they can even develop into cancer.
The study is significant because it means denosumab, which has a relatively low side effect profile compared to other cancer drugs, could be used as a non-surgical option to prevent aggressive breast cancer as a result of the faulty BRCA1.
Current prevention methods for women carriers of the BRCA1 gene mutation often involves the removal of breast tissue, or a prophylactic mastectomy, coupled with the removal of the ovaries.
Prof Sanchia Aranda, CEO of Cancer Council Australia, says the findings are exciting because the availability of a new non-invasive approach ultimately gives women another prevention option.
“This is an important study because it identifies a potential blockable mechanism for the way that cancer develops in women with BRCA1 mutation,” Prof Aranda tells SBS.
“The great thing about this study is that not only have they identified the potential mechanism, but because there’s a drug already existing it’s a very short timeline to potential clinical application as in the trials can start now.”
This means that researchers can skip the drug development stage altogether and focus on setting up clinical trials to monitor women with the BRCA1 mutation and the effects of denosumab over a number of years.
“What’s important about this is that it is linking a biological process with a readily available drug and hopefully that will shorten the pathway to having another treatment that women with BRCA1 mutations can consider in looking at reducing their cancer risk,” says Prof Aranda.
Prof Vidvader explains that although a small pilot study was already showing promising results, the next step would be to starts an international clinical trial and track the efficacy of denosumab in breast cancer prevention over a longer period.
“Even if it doesn’t totally prevent breast cancer, I hope that it will delay the decision for these younger women before they have to undergo a mastectomy and ovariectomy,” she says.