The cure for cancer patients is tough. It’s really a case of killing parts of your own body, and that’s never going to be easy.

With radiation treatment this process hinges on damaging tissue with radiochemical reactions and oxidative stress. The oxidative stress works by producing very reactive chemicals such as hydroxyl radicals (OH) and superoxide (O₂^-), also a radical.

This therapy isn’t very discriminating though; healthy cells are killed off as well as cancerous ones. Scientists at the University of Pittsburgh have been looking into the possibility of giving the healthy cells a bit of protection during the treatment of lung cancer. The idea is that at least this would reduce the damage to healthy tissue, and even give the possibility of  increasing the radiation dosage.

So what problems does radiation therapy cause? For lung cancer patients the problems arise in the oesophagus (the food pipe down to the stomach). The oxidants produced by the effects of the radiation must be akin to having your gullet weep bleach. This leads to problems such as severe inflammation and sometimes leads to ulceration. This can cause patients so much pain when they swallow that they are given pain relief with narcotics, or they have to have a break from the therapy.

What patients need is something to clear up these oxidants so that the radiation treatment doesn’t cause so much damage to the healthy cells. And it just so happens that there is already a protein available that can do just that; maganese superoxide dismutase (MnSOD). The name says it all really! MnSOD catalyses the decomposition of superoxide and so removes this very toxic molecule from cells.

The thinking is that to help radiation therapy patients, the level of MnSOD needs to be increased. This can be done using gene therapy. The medication is given orally and is made up of a plasmid (DNA molecule) inside a ball of cell membrane material (a liposome). When this is ingested the liposome is able to travel through the membrane of the cells in the oesophagus. Once inside the cell the plasmid can start making MnSOD. This can then scavenge for reactive oxygen species, such as superoxide.

This work is still at an early stage. Firstly, scientists needed to make sure that manganese superoxide dismutase plasmid liposome (phew!) doesn’t do any harm. So far, trials on ten lung cancer patients have shown that the side-effects of MnSOD-plasmid liposome are minimal – mild heart burn, rashes etc. It seems that MnSOD-plasmid liposome doesn’t linger in normal cells, and it doesn’t seem to protect cancerous cells either. The next stage is to extend the trial to find out if MnSOD-plasmid liposome can actually do what the researchers are hoping for; protect healthy cells from the effects of the radiation.

If MnSOD-plasmid liposome does the job it could mean happier radiation therapy for other cancer patients too. There is a possibility that sufferers from prostate cancer could gain protection from damage to their rectum, and the bladders of ovarian cancer patients could also be protected . It may well be that destroying tumours never felt so good.

See the original article at Experimental Radioprotective Drug Safe for Lung Cancer Patients