Cancer cells can consume neighbouring cells to survive chemotherapy, new research shows.

Doxorubicin is a common chemotherapy drug that works by selectively damaging the DNA of cancer cells. However, multiple cancer cells have been observed to survive doxorubicin treatment to allow a relapse of the disease. These cancer cells can enter a form of dormancy, known as senescence, to survive the damaging effects of chemotherapy.

During senescence cancer cells can still maintain their metabolic activity and release signalling molecules to continue to promote tumour growth. In this study, researchers wanted to understand the behaviour of senescent cells to identify therapeutic targets.

Breast cancer cells genetically engineered to induce fluorescence were treated by doxorubicin in both tumours and cell cultures. Using 3D time lapse microscopy, it was observed that some senescent cells were cannibalising their neighbours after chemotherapy treatment.

The cannibal cancer cells were found to have a set of genes switched on that are normally only switched on in macrophages. Macrophages can engulf foreign cells in a process known as phagocytosis. The cannibalistic cancer cells were able to survive longer after chemotherapy treatment than cells that did not cannibalise.

More research is needed to understand both how cannibalism helps cells survive senescence and how this can lead to relapse.

At the World Metastasis Summit, taking place in Boston this November, Nir Ben Chetrit from Meyer Cancer Center will be discussing Modelling the Tumor-Innate Immunity: Organoid Modeling and a Drug Discovery Platform of Innate Immunity in the Breast Cancer Microenvironment. You can view the full agenda here.