Researchers Think Cancer's Own Byproducts Could Help Kill If Off

In the UK, about 400,000 new cancer cases are diagnosed each year.

Though there are over 100 different forms of the disease, they all follow the same rough pattern: cells begin to grow uncontrollably and start to appear in parts of the body where they don’t belong.

This multiplication of cells can sometimes lead to a tumour, or a mass, which may spread. 

Researchers have long sought a way to stop this process. And in a new paper published in Nature, some suggest that a chemical byproduct of cancerous cells themselves could help to do so from within tumours. 

Carbon monoxide could play a role here

You’ve probably heard carbon monoxide (an odourless, invisible gas) described as a “silent killer” because it can poison people without them realising. That’s why carbon monoxide alarms are so important.

But our bodies also produce their own tiny stores of carbon monoxide, too. This isn’t enough to harm our health, but cancer cells contain an excess of the gas (it’s a metabolic byproduct for some of them). 

You might think this would kill off some of the cancer cells. But the problem is that carbon monoxide has “intrinsically low reactivity”, meaning it’d need some interventions (including the metal palladium) to actually have an effect on them. 

So, to help kill off cancer cells, researchers tried treating them with palladacycles, which are natural palladium-containing compounds.

Palladacycles react with carbon monoxide to create phenanthridinone, which is toxic to cells – phenanthridinone is already used in some cancer treatments.

But natural cleaning systems in our cells, like glutathione, break these palladacycles down before they can help to activate the carbon monoxide.

Still, researchers found that encasing the palladium-containing compound in albumin – a protein found on our blood – “shielded” it from these attacks via a “coumarin anchor”. 

This “anchor” essentially gave the palladacycles a place to hide, helping them to enter cells without being detected. And once they got in, poisonous phenanthridinone seemed to build.

What would stop this from harming healthy tissue?

After testing several palladacycles, scientists found what seemed to be the most promising candidate and tested it on human liver, breast, and lung cells, as well as a cancer-free set. 

After 48 hours, phenanthridinone had been formed in the cancerous cells, but not in the healthy ones. 

That may be because, as we mentioned before, cancerous cells carry a lot more carbon monoxide than do “normal” cells. 

After that, the scientists tweaked palladacycles to make them especially poisonous to cancer cells. In liver cancer cells, this seemed to have the intended effect of poisoning troublesome cells.

Researchers wanted to see whether existing carbon monoxide already present in healthy blood might kick this reaction off before palladacycles reached tumours. But blood tests suggested they didn’t – this might be because when the gas is in our blood, it binds to oxygen-transporting haemoglobin. 

Still, we’ll need more research to work out whether this treatment could be appropriate for humans.

The next step for researchers is to test this process in animal models, which might help to work out factors like dosage and how the proposed approach actually affects systems in real life.