New research, led by cancer biologists from the University of Bristol, has shown that bone marrow cells can protect cancer cells from a plant derived anti-cancer agent called parthenolide.

Current therapies for children with an aggressive type of cancer found in the blood, called t-cell acute lymphoblastic leukaemia (T-ALL), have increased survival rates to above 85% in developed countries. Unfortunately some children fail to respond to therapy and many suffer from serious side effects, highlighting the need to investigate other agents to treat this disease.

Parthenolide (PTL) is a natural plant extract that has previously shown excellent anti-leukaemia activity with minimal effects on healthy blood cells. However, some populations of these cancerous cells unfortunately remain resistant to parthenolide.

The new study, published in Haematologica, explores the mechanisms for this resistance. The University of Bristol reports the study authors found that protection against parthenolide is provided by the release of antioxidants by normal support cells derived from the bone marrow. By blocking the release of antioxidants a significant reduction in leukaemia cell resistance to parthenolide was seen.

Ben Ede, from Dr Allison Blair’s cancer stem cell lab in the University of Bristol’s School of Cellular Molecular Medicine, and first author of the study, said “This research shines light onto a possible reason why T-ALL cells become resistant to therapy inside the body. By understanding the different ways cancer cells interact with normal healthy cells to survive this will help us to devise strategies to enhance new and in use therapies, for the benefit of children suffering from this terrible disease.”

These findings indicate that it may be possible to improve the efficacy of parthenolide, as well as other chemotherapy drugs, by starving childhood T-ALL cells of anti-oxidants. The next step is to fully evaluate if blocking antioxidant release enhances anti-leukaemia drug effects in vivo.