Scientists in the Brindle lab have developed a way to image how tumours use glucose, which could be used to monitor tumour response to treatment in the clinic.
The research was published on Sunday in Nature Medicine.
Tumour cells proliferate rapidly, and consume much more glucose than healthy tissues. According to researcher Tiago Rodrigues, “…a higher consumption of glucose by a given tumour is usually correlated with poor prognosis and with increased tumour aggressiveness and metastasis”. Therefore, being able to monitor the process by which tumour cells use glucose would allow researchers to monitor tumours’ response to treatment.
The team used a technique called hyperpolarisation to label the carbon atoms in glucose molecules, which produces a signal that can be recorded by the scanner. As glucose is broken down and made into new molecules, researchers can follow the labelled carbons as they are incorporated into new molecules, and therefore follow a cell’s glucose consumption and metabolism.
An example of images produced by the scanner and subsequent analysis. The 1H-MRI image shows the position of the tumour, outlined by a white line. The 13C-glucose image shows that glucose is being used both by the tumour and normal tissue, however the tumour is using more, as indicated by the white and yellow colours. Red shows lower levels of glucose consumption. The 13C-urea image is a control that the researchers use to check that they are picking up the signals correctly. The 13C-lactate image shows that lactate, a product of glucose breakdown, is being produced at higher levels in the tumour than in healthy tissue, indicated by the white, yellow and red areas. This is caused by higher consumption of glucose in the tumour. Rodrigues et al., Nat Med 2014; 20: 93.
The researchers found that they could monitor tumour response to a chemotherapy drug. “We were able to show that the drug etoposide was damaging the cancer cells (in a lymphoma model) at a very early stage of treatment, because the damaged cancer cells don’t convert the glucose to other products so efficiently” says Rodrigues.
The hyerpolarised MRI technique also has an advantage over other imaging techniques as you can see small differences in tumour metabolism, which might be missed by other imaging techniques. “This [technique] could be particularly important to detect and to assess early treatment response in those tumours where FDG-PET shows poor contrast, such as those in brain and prostate”, Rodrigues says, adding that another advantage of the method is that “it does not use ionising radiation, so repeated measurements can be made during treatment”.
11 Dec 2013