TO BE, OR NOT TO BE
THE QUESTION OF BREAST MILK’S BUG-KILLING POWER
We clear the stage for HAMLET. Not the play, but a substance that was recently discovered in human breast milk. Shambralyn Baker explains how this magic molecule could mean a novel cancer treatment and the end of the MRSA ‘super-bug’.
What do Shakespeare and MRSA have in common? Up until now, probably nothing at all. However, that could all be about to change with the discovery of ‘HAMLET’ – a substance found in human breast milk. This bug-killer may just be the end of antibiotic resistant bacteria.
From underwater steam vents to rainforests filled with exotic plants, the search for new and better drugs spans the globe. Now, scientists at the University at Buffalo, State University of New York, have found something that can help fight the ‘ superbug’ MRSA, and it’s produced not in a remote forest, but closer to home – in the human breast. HAMLET ( Human Alpha-lactalbumin Made LEthal to Tumor cells) is a substance made of protein and lipid (fat) found in human breast milk. Researchers at Lund University in Sweden have discovered that it can kill cancerous cells without harming healthy cells. Furthermore,
research published in May of this year shows that HAMLET also makes antibiotics more effective: when the researchers used a mix of HAMLET and methicillin (a particular type of antibiotic) against strains of ‘superbug’ MRSA (Methicillin-resistant Staphylococcus aureus) they found the number of bacteria present reduced significantly. Normally, Staphylococcus bacteria are harmless and sit on the surface of the skin, but they have the potential to cause a wide variety of problems, from minor skin infections to sepsis – and even death. But it is the multi-drug resistant MRSA that causes real trouble, not only because of the harm it can do to our bodies, but because it can be so difficult to treat.
Killing the unkillable
MRSA first became resistant to an antibiotic called methicillin before becoming immune to the effects of other antibiotics. Worryingly, even vancomycin, the ‘drug of last resort’ (so called because it remained effective against MRSA even when other antibiotics were beginning to fail) is losing its fight against MRSA. Such ‘last resort’ antibiotics normally work by preventing the bacteria from making the protective cell walls they need to survive. However, some MRSA strains have developed the power of antibiotic resistance: they can continue to make effective cell walls even when antibiotics are present. So how does HAMLET help these antibiotics regain their potency? It blocks special pumps that MRSA uses to remove those chemicals
that are toxic to it (in this case, the antibiotics). With their detox system out of commission, the antibiotics can start to accumulate inside the MRSA – and have their desired effect. One of the big challenges when it comes to fighting MRSA is that it can evolve to become immune to antibiotics. As a result, MRSA usually forces doctors to rotate through multiple antibiotics until they eventually find a drug-cocktail that works. And the more they use that particular cocktail, the faster MRSA gains resistance. The great thing about HAMLET is that MRSA cannot become immune to it. It’s the equivalent of forcibly overriding the firewall on a computer: HAMLET forces the bacteria to become susceptible to antibiotics by overriding their usual defense mechanism. The researchers also found that even after upping the dose of methicillin (something that would normally encourage the bacteria to become resistant) the bacteria remained susceptible to it – as long as HAMLET was also present. As the research into the HAMLET protein continues, how many more uses will we find for it? After all, MRSA is only one type of antibioticresistant bacteria. Hopefully HAMLET will prove effective on other troublesome bugs. And the fact that it was found in breast milk is just one more example of how amazing the human body is.
BELOW: An abscess caused by methicillinresistant Staphylococcus aureus (MRSA) bacteria.
ABOVE: Scanning electron micrograph of MRSA and a dead white blood