Asteroid that killed dinos could help fight cancer

London, Nov 3 (IANS)  A 10-km wide asteroid that wiped out dinosaurs when it crashed into earth over 65 million years ago contains a rare metal -- iridium - that could be used in the effective treatment of cancer, researchers have found.

Scientists from the UK and China have demonstrated that iridium - a rare metal delivered to Earth by the asteroid - can be used to kill cancer without harming healthy cells.

Laser-based techniques are emerging as viable treatments for cancer, targeting tumours far more precisely than the shotgun blast of radiation and chemotherapy. Researchers from the University of Warwick in the UK and Sun Yat-Sen University in China have found that laser light can turn iridium into an effective cancer killer, the newatlas.com reported.

The team created a compound of iridium and organic materials, and then introduced it into a lung cancer tumour grown in the lab. When red laser light is shone onto it through the skin, the compound is activated, converting the oxygen in the tumour into singlet oxygen, a poisonous form of the element that effectively kills the cancer cells from the inside. With cancer becoming resistant to certain treatments, it's crucial to find new methods such as this.

Further study found that the compound was effective as it managed to penetrate every layer of the tumour.

The team used ultra-high resolution mass spectrometry to highlight which proteins in the cancer cells were being targeted. They found that the compound had damaged proteins that manage heat shock stress and glucose metabolism, which are known to be crucial molecules for cancer's survival.

When the researchers tested the iridium compound on a clump of non-cancerous tissue they found it had no effect, meaning it seems to be a highly targeted treatment that doesn't attack healthy cells. The research was published in the journal Angewandte Chemie.

Iridium is relatively rare on Earth naturally, but scientists have found a spike in the Chicxulub crater, an impact crater buried underneath the Yucatán Peninsula in Mexico, which is often associated with the asteroid impact that wiped out the dinosaurs.

"The precious metal platinum is already used in more than 50 per cent of cancer chemotherapies," says Peter Sadler, lead author of the study. "The potential of other precious metals such as iridium to provide new targeted drugs which attack cancer cells in completely new ways and combat resistance, and which can be used safely with the minimum of side-effects, is now being explored. It's certainly now time to try to make good medical use of the iridium delivered to us by an asteroid 66 million years ago!"