Simply shining light on dinosaur metal compound kills cancer cells

February 4, 2019, University of Warwick
Simply shining light on dinosaur metal compound kills cancer cells
Iridium with its organic coat which is hooked up to the protein albumin (HSA). Together that enter cancer cells and deliver the iridium photosensitizer to the nucleus. On irradiation with blue light, the iridium not only glows green, but converts oxygen in the cell to a toxic form called triplet oxygen, which kills the cell. Credit: University of Warwick

A new compound based on Iridium, a rare metal which landed in the Gulf of Mexico 66 M years ago, hooked onto albumin, a protein in blood, can attack the nucleus of cancerous cells when switched on by light, University of Warwick researchers have found.

The using light, called Photodynamic therapy, is based on called photosensitizers, which can be switched on by light to produce oxidising species, able to kill cancer . Clinicians can activate these compounds selectively where the tumour is (using optical fibres) thus killing cancer cells and leaving intact.

Thanks to the special chemical coating they used, the Warwick group was able to hook up Iridium to the blood protein Albumin, which then glowed very brightly so they could track its passage into cancer cells, where it converted the cells' own oxygen to a lethal form which killed them.

Not only is the newly formed molecule an excellent photosensitiser, but Albumin is able to deliver it into the nucleus inside cancer cells. The dormant compound can then be switched on by light irradiation and destroy the cancer cells from their very centre.

The bright luminescence of the iridium photosensitiser allowed its accumulation in the nucleus of tumour cells and its activation leading to the cancer cell death to be followed in using a microscope.

Simply shining light on dinosaur metal compound kills cancer cells
The purple stain for cancer cell nuclei overlaps perfectly with the emission of green light from the iridium-albumin conjugate, showing the protein has delivered the photosensitizer to the nucleus of cancer cells. Credit: University of Warwick

Professor Peter Sadler, from the Department of Chemistry at the University of Warwick comments:

"It is amazing that this large protein can penetrate into and deliver iridium which can kill them selectively on activation with visible light. If this technology can be translated into the clinic, it might be effective against resistant cancers and reduce the side effects of chemotherapy"

Dr. Cinzia Imberti, from the University of Warwick comments:

"It is fascinating how albumin can deliver our photosensitiser so specifically to the nucleus. We are at a very early stage, but we are looking forward to see where the preclinical development of this new compound can lead."

Simply shining light on dinosaur metal compound kills cancer cells
The purple stain for cancer cell nuclei overlaps perfectly with the emission of green light from the iridium-albumin conjugate, showing the protein has delivered the photosensitiser to the nucleus of cancer cells. Credit: University of Warwick
"Our team is not only extremely multidisciplinary, including biologists, chemists and pharmacists, but also highly international, including young researchers from China, India and Italy supported by Royal Society Newton and Sir Henry Wellcome Fellowships."

The paper 'Nucleus Targeted Organoiridium-Albumin Conjugate for Photodynamic Cancer Therapy' has been published in Angewandte Chemie International Edition.

Explore further: Cancer cells destroyed with metal from the asteroid that killed the dinosaurs

More information: Pingyu Zhang et al, Nucleus-Targeted Organoiridium-Albumin Conjugate for Photodynamic Cancer Therapy, Angewandte Chemie International Edition (2018). DOI: 10.1002/anie.201813002

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Display comments: newest first

1 / 5 (4) Feb 04, 2019
which landed in the Gulf of Mexico 66 M years ago
Notice that if you remove this phrase from the text, the text remains untouched in meaning.
This is a simple illustration that the evolutionary mythical tale is totally irrelevant to progress in real medical and other biological research.
As for this research - I'm very happy that highly intelligent people are working so hard to bring relief to the millions that are suffering from cancer, which is itself a consequence of the fall.

Disease, pain, suffering and death - these are all a direct result of the sin that Adam committed at the beginning. If you think this is a myth - which most people do - ask yourself why there is suffering in the world and why we are trying so hard to reduce it and avoid death. If death was the growth engine for life, why don't many more people and animals not simply commit suicide so that life can flourish without them-or why don't we give them a helping hand in that direction?Think Euthanasia?
Da Schneib
3 / 5 (4) Feb 04, 2019
@FreddyJoe thinks the Babble about the super magic sky daddy by the drunken stone age sheep herders talks about iridium.

Nutjob detected.

Go sit by the oil drum fire and tell the other inhabitants of the trailer park how you cured cancer, @FreddyJoe.
5 / 5 (1) Feb 04, 2019
The 'dinosaur' reference in the title and the reference to the arrival of iridium have nothing to do with the research, and the paper itself makes no mention of them.

Usually it is some reporter who puts in 'clickbait', but in this case it appears that some silly public relations person at the university did a search on 'iridium' and regurgitated the irrelevant material from the search.
Da Schneib
3 / 5 (2) Feb 04, 2019
Yeah, @Real, that was my impression too.

The abundance of iridium in the Earth's crust is very low, whereas it's much higher in asteroids and meteorites, so it's quite noticeable in the geological record when an asteroid impact occurs and spreads it far and wide. Current geological theories are that it's more common in the mantle and core.

In the amounts likely to be used in cancer therapy it's not limited.
not rated yet Feb 06, 2019
@DS - the Iridium-rich layer marking the end of the cretaceous is 5 mm to 10 mm thick (UCMP Berekely), and has 100X the iridium concentration (wikepedia), so its total iridium is only the same as a meter of normal sediment.

So as noticeable as that layer is, its total iridium is a very small fraction of our crust's total iridium (<<1%), and only a PR hack would call it 'dinosaur metal'. Now the TOTAL iridium from all late impacts may be a very significant fraction of the iridium in circulation, so while calling it a 'meteor metal' would still be irrelevant to the article, at least it would not be as absurd as calling it 'dinosaur metal'.

But the article is already interesting without some PR department adding irrelevant fluff, so I'd prefer the the PR department stop trying to 'enhance' it.

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