Hope for treating triple negative breast cancer: New drug ‘starves’ tumor cells by killing off the protein that fuels their growth
- About a fifth of all breast cancers are triple negative, the hardest form to treat
- Scientists at Mt Sinai in New York found a protein that fuels the tumors’ growth
- They developed a drug that can ‘degrade’ the protein to slow tumor growth in petri dish and animal studies
A drug that stops the the deadliest form of breast cancer in its tracks has been developed.
The experimental therapy on triple negative breast cancer worked on human tumor cells grown in the lab and living mice.
It prevented the disease spreading – a process called metastasis. Scientists are hopeful of similar success in humans.
Triple negative breast cancer has few effective treatment options, migrates further than other types and is more likely to recur and prove fatal. Younger women are most prone.
The medication called MS1943 destroys a protein known as EZH2 that fuels its growth – while leaving healthy cells alone.
A newly-developed drug may prevent hard-to-treat triple negative breast cancers from growing by killing off the proteins that fuel tumor growth, animal studies suggest
Dr Jian Jin, director of the Mount Sinai Center for Therapeutics Discovery in New York, said: ‘Our findings suggest EZH2 selective degraders such as MS1943 may provide an emerging therapeutic approach for the treatment of triple-negative breast cancer.’
Breast cancer is the most common cancer in the US. Around 271,000 women are diagnosed each year – up to a fifth being struck down with the most aggressive.
In tests of miniature triple negative breast cancer tumors in petri dishes and in mice, blocking EZH2 completely prevented them from metastasizing.
There’s not yet a drug that can be used in women that manages the same thing, said Dr Jin.
He said: ‘Triple-negative breast cancer represents 12 to 20 percent of all breast cancers.
‘It has poor prognosis, high recurrence, a low survival rate and has higher incidence in African-American and Hispanic women.
‘Currently, there are no effective therapies for treating a substantial portion of patients.’
They believe the new drug, described in Nature Chemical Biology, could also treat prostate cancer – the most common in men.
Dr Jin said: ‘The EZH2 selective degrader reported in this study is also an invaluable tool to test therapeutic hypotheses in other cancers.’
The protein is over-expressed in many tumors – including breast and prostate
He said: ‘In breast cancer, EZH2 has been identified as a major driver for disease development and progression, and high levels correlate with poor prognosis.’
Several clinical trials of EZH2 inhibitors have already shown promise in treating sarcomas and lymphomas – tumors that start in soft tissue and immune cells respectively.
Dr Jin said: ‘MS1943 contains chemicals that are very toxic to triple negative breast cancer cells – while sparing normal cells.
‘It’s effective in living animals – suggesting pharmacologic degradation of EZH2 can be advantageous for treating the cancers that are dependent on EZH2.’
His team also found MS1943 reduced EZH2 levels in lab tests on lymphoma cells and non-cancerous prostate cells.
Dr Jin said: ‘Our results suggest pharmacological degradation of EZH2 may offer a potential therapeutic strategy for triple negative breast cancer.
‘Furthermore, based on the oncogenic role of EZH2 in other cancers including prostate cancer, we hypothesise degraders could be effective in treating these tumours.
‘MS1943 is a valuable tool to test this therapeutic hypothesis.’
An estimated 268,600 new cases of breast cancer are expected to be diagnosed in 2019 in the US – with as many as one-in-five being the dreaded triple negative.
Chemotherapy is considered effective but the cancer often comes back – with a vengeance.
Triple negative breast cancer is a form of the disease that does not have receptors for the hormones oestrogen or progesterone, or the protein HER2.
This makes it trickier to treat due to the tumour not responding to these hormonal or protein therapies.
The condition is more common in those under 40 and black women. It is diagnosed via a sample of the cancerous cells.