How ‘unboiling an egg’ leads to better cancer treatments

 

 There is a famous adage in physics that says, “your theory may be beautiful, but if it isn’t absolutely hilarious, you are probably just wasting your time.” The most astonishing scientific discoveries are often those that surprise us enough to make us laugh before we even have time to think. When our thoughts finally do catch up with our eyes and ears, we have been changed — inevitably, we come to know a little bit less, because some of the explanations we once held dear can no longer be true.
On the other hand, we also become a little bit wiser as those explanations that survive grow stronger. One thing most of us “know” is that you can’t unscramble an egg. Even if you could, you couldn’t possibly unboil an egg. One need do no more than trot out simple thermodynamics to show that the heat applied to the egg irreversibly denatures its proteins. As the saying goes, Humpty Dumpty could never be be put back together again.
But eggs, particularly their proteins and DNA, are not really so simple. When swaddled with more sober amounts of heat, they become chickens. In fact, if you treat a boiled egg right, it is even possible to unboil it. The guy who discovered that just received the Ig Nobel Prize last month for the method he published earlier this year. Colin Raston, of Flinders University in Adelaide, didn’t set out to unboil eggs or win an Ig Nobel. He wanted to find a general way to unravel and untangle proteins. To do that, he built a vortex machine capable of mechanically separating long strands of proteins that had been pre-processed with urea.

Urea not only chews up and unfolds proteins, but it also coats and protects them against re-aggregating in the vortex drive. When an egg is cooked, one of the first proteins to begin to gel is lysozyme. This multifunctional bactericide is naturally abundant in egg whites, and is also found in places like tears, saliva, milk, and mucus. When proteins such as lysozyme are heat-denatured, electrical charges that were originally ensconced away on the protein’s interior are exposed when it unfolds. That makes them available to bond into larger conglomerates that, incidentally, will scatter light more effectively.
Raston and his colleagues first perfected their methods with lysozyme and then moved on to larger proteins. They were even able to get proteins to refold back into their native forms within a few minutes. This is a huge improvement over the standard dialysis techniques now used, which more likely will take all day to do that. Refolding crystallized clumps of proteins is a bit more complicated than, for example, re-ordering grain structure in heat-treated metals. But it may be a good analogy for us here at a basic level. When proteins useful to humans are made on an industrial scale by coaxing bacterial into synthesizing them in huge vats, the main difficulty is that it requires more than just controlling the temperature to prevent them from crystalizing out into sticky clumps.
The way that a healthy cell controls its protein factories is to bind the growing tapes of amino acids with little protector molecules as they are being translated on the ribosome. This prevents the protein from folding prematurely before the full strand is done. If a human protein is instead expressed in bacteria and synthesized in a big vat, many of the essential accessory molecules and templates needed for proper folding are likely missing. To fully replicate all those cozy eukaryotic intangibles that our proteins have become accustomed to and rely on for proper assembly, within in an amorphous primitive bacterial slurry, is still a difficult challenge. If these so-called ‘recombinant’ proteins being synthesized are actually drugs for treating cancer, processing inefficiencies end up costing a lot of time and money.
Recombinant forms of insulin, for example, can alleviate the need to use inferior or inconvenient ‘natural’ sources (like cows) to make them for us. But insulin is a fairly simple peptide whose secondary folded structure is fairly well understood. Newer drugs like the ZMapp used to treat Ebola contain several antibody proteins which are only just beginning to be understood. The best way to produce ZMapp has been to splice the genes for it into a tobacco plant where the products could be later harvested. At the height of the Ebola scare there was simply no way to produce quality ZMapp in the quantities that would be needed in the case of an epidemic.

As far as cancer, understanding folding has important implications beyond just making drugs. Misfolding is a double-edged sword in that it can be both a cause and an effect of tumerogenicity. For example, the energetic deficits commonly observed in cancer cells can result in an oversupply of misfolded proteins. On the other hand, it is sometimes misfolded proteins themselves that can be the cause of the cancer. Much the same conundrum has been seen in the role of mitochondria as compared to genetic mutations in cancer. Although mutations can clearly result in over-expression of the so-called ‘oncogenes’ that make cells multiply uncontrollably, researchers now appreciate that energetically compromised mitochondria may be the more fundamental driver of tumor progression.
When mutation is understood to occur as the result of the energetic failure of normal repair mechanisms, or secondary to metabolic adjustments to that failure, the spectrum of cancer causes and effects comes full circle. As mentioned above, treating cancer can now be an expensive proposition, particularly some of the eclectic antibody drugs typically recognized by a fancy name ending with the suffix ‘mab’ (for monoclonal antibody). Antibodies are basically the universal computers of the immune system, in the sense that can be made on demand to recognize just about any molecule one can imagine. Anything from large viral coat proteins, to small metals, and perhaps even to things no less slippery than teflon itself.
Tales of $1,000-per-dose regimens for tough-to-treat tumors are no exaggeration. One drug commonly used as part of a cocktail elixir given for certain white-cell cancers — B-cell tumors or Hodgkins for example — is Rituximab. This is an interesting one, because it comes off of patent protection this year and can theoretically be opened up to the beneficial effects of greater competition. B cells are the cells which are responsible for making our own antibodies to pathogenic invaders. What we potentially have here is the prospect of treating faulty antibody-producing cells, crippled by their own misfolded proteins, with separate antibody drugs manufactured by controlling proper folding to target those proteins.
When the Ig Nobel prize givers say that their goal is as much to make us laugh as it is to help us learn, they are absolutely serious. Lest anyone doubt their success so far, we might note they are gaining in popularity compared to the ‘real’ Nobel prize. For example, who knows the recipients that won the Nobel yesterday in chemistry for their work on the DNA toolbox for cell repair? Perhaps a few, but at least now, you all know the chemist that won the Ig Nobel for unboiling an egg.