Image: Professor Nandita de Souza at the ICR's Cancer Research UK Cancer Imaging Centre.
A weight loss drug available over the counter in the UK could help women with treatment-resistant ovarian cancer respond to chemotherapy again, a new study suggests.
Researchers from The Institute of Cancer Research, London, treated chemotherapy-resistant ovarian cancer in mice with the obesity drug orlistat – the active ingredient in some slimming pills.
Orlistat helped the ovarian cancers become sensitive to the chemotherapy treatment cisplatin and delayed tumour growth, compared with using either treatment alone.
The study was published in the International Journal of Cancer, and was funded by the Cancer Research UK Cancer Imaging Centre at the ICR.
Chemotherapy is one of the main treatment options for ovarian cancer, but once resistance develops it can be very difficult to treat the disease.
Weight loss drug orlistat could treat cancer
Orlistat is the active ingredient of drugs available in the UK which can help people lose weight.
It works by blocking the enzymes in the stomach and intestines that break down fat from the diet, reducing the absorption of fat into the body. Orlistat has also been found to prevent the activity of another protein in cells called fatty acid synthase (FASN), which builds fatty acids.
Many types of cancer produce more fatty acids than normal to help cancer cells grow, a process which is regulated by FASN.
Increased FASN activity is linked to more aggressive cancers and drug resistance, so orlistat could potentially enhance cancer treatment by blocking the activity of FASN.
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Orlistat recovers sensitivity to chemotherapy
ICR researchers used combinations of orlistat and the chemotherapy drug cisplatin to treat chemotherapy resistant ovarian cancers grown in mice.
They found that orlistat together with the chemotherapy treatment cisplatin was much more effective than either treatment alone.
Mice treated with orlistat and cisplatin showed significant delays in tumour growth, compared with untreated mice.
Importantly, they saw this combination treatment did not cause weight loss in mice at the doses they used.
This suggests that in the future, patients might be able to benefit from the possible anti-cancer effects of orlistat without losing weight, which could be problematic for people with cancer.
Improving outcomes for ‘tried and tested’ cancer treatments
Study lead author Dr Yuen-Li Chung, senior staff scientist in the Cancer Research UK Cancer Imaging Centre at the ICR, said:
“Chemotherapy is a tried and tested way of treating cancer, so it’s important to find new drug combinations that keep them working in cancer as long as possible. Our research shows that the weight-loss drug orlistat, previously shown to have anti-tumour effects in a range of cancers, can recover ovarian cancer’s sensitivity to cisplatin in mice.
“Our research shows that combining orlistat with cisplatin could potentially be an effective way to treat women with advanced ovarian cancer that has stopped responding to chemotherapy.”