Scientists have found a way to pull down the protective wall that surrounds tumours, potentially re-exposing them to the killing power of the immune system and immunotherapy treatments, Cancer Research UK has announced.
A study published in EBioMedicine found that the approach could help to boost the effects of innovative cancer treatments, such as CAR-T therapy, which so far haven’t been used successfully to tackle solid tumours.
Drs Francis Mussai and Carmela De Santo, based at the University of Birmingham, studied immune cells called myeloid-derived suppressor cells or ‘MDSCs’, taken from the blood of 200 adults and children newly diagnosed with cancer before they had started treatment.
These cells send out a barrage of chemical signals that shield tumours cells from the immune system and the effects of treatment, and prevent the activation of T cells that can kill tumour cells.
When MDSCs are present in higher numbers, the outlook for patients is worse as their cancer can become resistant to treatment and is more likely to spread to other parts of the body.
Dr Francis Mussai, lead author of the study and Cancer Research UK Clinical Scientist Fellow at the University of Birmingham, explained that “treatments that work with the immune system to kill cancer often fail because it can be difficult for our body’s defences to get access to the tumour cells. Our research indicates that giving this antibody drug alongside immunotherapies could dramatically increase the number of patients benefitting from the latest innovations in treatment.”
Previously, researchers in another group had found a way to break the protective layer around tumours in mice by using antibodies that attach to the MDSC cell surface, marking it for destruction by the immune system. But translating this into clinical trials has been challenging because researchers have been unable to find a drug target that’s present on human MDSCs.
The team are now planning a clinical trial to test the safety and activity of the antibody drug in people with hemophagocytic lymphohistiocytosis and macrophage activation syndrome. The trial will also include people with solid tumours.