Anti-parasite drugs for river blindness could treat breast cancer
Scientists have discovered that cheap drugs used to treat parasitic worms and conditions such as river blindness could treat a type of breast cancer that often fails to respond to standard therapies.
Triple-negative breast cancer accounts for about 1 in 5 cases of breast cancer (15-20 per cent). It can be more difficult to treat than other breast cancer types, as it doesn’t respond to hormone therapy or targeted treatments like Herceptin or tamoxifen.
Triple-negative breast cancer is thought to be caused, in part, by epigenetic changes – where genes are not mutated but are switched on and off in cells. A key driver of these epigenetic changes is SIN3.
In this study, scientists analysed the molecular structures (shape) of 2,000 clinically approved drugs to identify chemical targets that could interact with SIN3 and stop it binding (sticking) to partner proteins, which would stop SIN3 from working. Surprisingly, they found that two drugs were able to block SIN3 activity. These drugs are part of a family of compounds that work as anti-parasite drugs, called avermectins.
In lab tests using breast cancer cells, the two drugs helped stop tumour growth and spread.
In addition, the drugs made the cells more sensitive to tamoxifen. This opens up the possibility that the avermectins could be used in combination with tamoxifen to treat triple-negative breast cancer.
Spurred on by these exciting findings, they investigated if the same was true in animal models. Using mice with triple-negative breast cancer, they found treatment with one of the drugs shrunk tumours and reduced the likelihood that they would spread to other areas, like the lungs.
Dr Chris Lord, Leader of the Gene Function Team at the Institute of Cancer Research, said: “Triple-negative breast cancers are often difficult to treat. Our results suggest that these cheap, readily available drugs could offer an exciting, cost-effective way to treat triple-negative breast cancer, either on their own or in combination with other treatments already in use.
We found that drugs called avermectins, which are used to treat parasitic diseases like river blindness, were able to bind to a protein implicated in the progression of triple-negative breast cancer. They silenced (turned off) genes important for breast tumours to grow and spread, while activating (turning on) genes that sensitise cancer cells to the common hormone therapy tamoxifen.”
He concluded “It would be very interesting to see whether these drugs work as well in patients as they do in mice.”
The study was funded by Leukaemia and Lymphoma Research, with additional funding from Worldwide Cancer Research. Read more here.
Find out more about our current research where Professor Vaux is testing a new drug for triple-negative breast cancer, or Professor del Pozo work trying to find new therapies for triple-negative breast cancer.
Worldwide Cancer Research have funded several projects that have found new uses for non-cancer drugs in treating cancer. Find out more about repurposing old drugs in our blog on the diabetes drug metformin and its potential use in cancer treatment.
Image courtesy of pixabay.com, CC0 1.0 Universal (CC0 1.0).