Recent research by the University of Otago, Wellington has shown that giving brain cancer cells high dose vitamin C makes them much more susceptible to radiation therapy.
The study, carried out in association with Wellington’s Malaghan Institute was recently published in Free Radical Biology and Medicine.
Lead author Dr Patries Herst together with Dr Melanie McConnell investigated how combining high dose vitamin C with radiation affected survival of cancer cells isolated from glioblastoma multiforme (GBM) brain tumours, and compared this with the survival of normal cells.
They found that high dose vitamin C by itself caused DNA damage and cell death which was much more pronounced when high dose vitamin C was given just prior to radiation.
Herst says GBM patients have a poor prognosis because the aggressive GBM tumours are very resistant to radiation therapy. “We found that high dose vitamin C makes it easier to kill these GBM cells by radiation therapy”.
She says there has long been debate about the use of high dose vitamin C in the treatment of cancer. High dose vitamin C specifically kills a range of cancer cells in the laboratory and in animal models. It produces aggressive free radicals in the tumour environment but not in the environment of healthy cells. The free radicals damage DNA, which kills the cells, but the high concentration necessary to kill cancer cells can only be achieved by intravenous injection.
However, these promising findings have so far not been validated in clinical studies. “If carefully designed clinical trials show that combining high dose vitamin C with radiation therapy improves patient survival, there may be merit in combining both treatments for radiation-resistant cancers, such as glioblastoma multiforme,” says Dr Herst.
Herst PM, Broadley KWR, Harper JL, McConnell MJ. Pharmacological concentrations of ascorbate radiosensitize glioblastoma multiforme primary cells by increasing oxidative DNA damage and inhibiting G2/M arrest. Free Radical Biology and Medicine 2012; 52 (6). Available online 2 February 2012.