By shining a red laser beam through the skin, scientists discover how an Iridium compound can selectively target cancer.
The rare earth metal is yellow, hard brittle and stems from the same elemental family as platinum, the most valuable metal on Earth. Iridium is rare on our home planet, yet plentiful in asteroid matter. The largest deposit of Iridium ore discovered on Earth dates back 66 million years ago to when the dinosaurs went extinct. So they believe that most if not all the Iridium on Earth was brought here by small meteoroids and larger colliding asteroids such as the one that destroyed the dinosaurs.
Researchers discovered the life-saving ability after they combined Iridium with an organic material, creating what is called a metal organic framework. This new compound is capable of infiltrating cancer cells and energizing the oxygen (O2) inside until it breaks apart in to a poisonous single atomic derivative that can destroy the cell.
“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,” says study coauthor Cookson Chiu, a postgraduate researcher in the chemistry department at the University of Warwick.
In order to trigger the process, scientists shine a visible red laser light through the skin and over the tumor, stimulating organic iridium compounds to begin oxygen deconstruction. In this experiment they were able to demonstrate the efficacy of organic iridium compounds in treating lung cancer by destroying cancerous cells while leaving ordinary cells alone.
“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,” says Pingyu Zhang, a fellow in the chemistry department at the University of Warwick.
In order to confirm their findings, scientists peered through a brand new ultra-high resolution mass spectrometer, closely observing the individual response of different proteins to the iridium compound.
“Remarkable advances in modern mass spectrometry now allow us to analyze complex mixtures of proteins in cancer cells and pinpoint drug targets, on instruments that are sensitive enough to weigh even a single electron!” says Peter O’Connor, professor of analytical chemistry.
They learned that the iridium compound works by targeting proteins responsible for regulating heat shock stress and glucose metabolism, which are molecules that contribute to the growth of cancer.
“The precious metal platinum is already used in more than 50 percent 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,” says Peter Sadler, whose lab is in the department of chemistry at the University of Warwick.
Sadler adds: “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!”