Metal hope for cancer therapy

A new method of destroying cancer cells is being investigated by researchers at Warwick University, UK, in collaboration with a team from China.

Professor Peter O’Connor and his team looked at the possibility of using the dense metal iridium to fill cancer cells with a destructive version of oxygen, in a process that spares healthy tissue. The destructive oxygen particles are activated by laser light, the team explains.

The work builds on the team’s knowledge of the specific areas of cancer cells that are affected by treatment, which they discovered by analysing thousands of cell proteins with mass spectrometry.

Professor O’Connor said: "Remarkable advances in modern mass spectrometry now allow us to analyse complex mixtures of proteins in cancer cells and pinpoint drug targets, on instruments that are sensitive enough to weigh even a single electron.

"The precious metal platinum is already used in more than 50% of cancer chemotherapies. 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.

"International collaborations can greatly hasten progress. 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!"

Co-author Dr Cookson Chiu, also at Warwick, added: "This project is a leap forward in understanding how these new iridium-based anti-cancer compounds are attacking cancer cells, introducing different mechanisms of action, to get around the resistance issue and tackle cancer from a different angle."

First author, Dr Pingyu Zhang, commented: "Our innovative approach to tackle cancer involving targeting important cellular proteins can lead to novel drugs with new mechanisms of action. These are urgently needed."

Details appeared recently in the journal Angewandte Chemie.

Zhang, P. et al. Organo-iridium photosensitizers can induce specific oxidative attack on proteins in cancer cells. Angewandte Chemie 19 October 2017; doi: 10.1002/anie.201709082 [abstract]