Iron in cosmic rays can trigger cancer in cells it never touches
Researchers found that cells hit by cosmic ray iron ions push their neighbours toward tumours, and they found a way to block it.
Galactic cosmic rays may do their worst damage to astronauts through the cells they miss, not the ones they hit. Researchers at Oklahoma State University and the University of Texas Health Science Center found that a cell struck by a heavy iron ion sends out chemical signals that push its unharmed neighbours toward cancer.
On a three year round trip to Mars, estimates based on Curiosity's flight data suggest only about 3 percent of an astronaut's cells would take a direct hit from an iron ion. The team bombarded human blood vessel lining cells with iron ion beams at the NASA Space Radiation Laboratory at Brookhaven. The struck cells triggered a long running inflammatory loop, releasing the signalling molecule TNF alpha for up to three days.
Lung lining cells that shared only liquid with the irradiated cells, without touching them, showed spikes in free radicals and double strand DNA breaks, and their normal safeguards against runaway growth were switched off. When those bystander cells were implanted in mice, they grew tumours.
Blocking the TNF alpha receptor broke the chain and spared the cells. The researchers suggest pairing drugs like that with shielding such as water walls and hydrogen rich plastics on deep space missions.
SourceUniverse TodayPhys.org