So this is almost entirely based on a comment in the "it's all converging together" thread, and an insight I had yesterday after talking to a post-doc in my lab about a seminar I missed by the noted cancer researcher Craig Thompson from UPenn.
Thompson and others have been influential in promoting the "it's all about the economy, stupid" theory of cancer cell survival, namely that in order to divide, a cell needs to first double its mass, and that takes ENERGY and raw materials. Lots of 'em. And isn't it intersting that instead of focusing on the efficient pathways that all normal cells use for energy extraction, cancer cells instead focus on short-term, easily extracted gains to fuel their massive expansion. Sound familiar?
More below the fold...
The geopolitics of the American empire (or I guess really the global empire, including China Japan and India) fit the progression of cancer almost to a T. It's spooky. Craig Thompson's talk was on cancer cell bioenergetics, that is how rapidly dividing cells (which aren't meant to divide so rapidly for the benefit of the organism) extract enough cheap energy to sustain their growth. Because in order for a cell to divide, it's gotta double its mass and macromolecular content.
Here's where it gets interesting. Eukaryotic cells (i.e. every organism except bacteria) have developed a neat trick whereby they can extract virtually the entire energy from a molecule of glucose (a sugar), the preferred energy source for most every cell. It's a complicated process, and it takes about 25-30 different steps, but in the end, a glucose molecule is completely oxidized to 6 carbon dioxides and 6 waters, consuming 6 oxygens in the process.
This development was absolutely crucial for the early eukaryotes (think yeast and fungi) to survive in environments with unpredictable energy supplies. That it has been maintained throughout evolution is a testament to how important it has been for life to extract every last bit of energy it can from its source. What's more, is that non-plant life has found a mutual friend and symbiotic partner in plants as they are able to do the reverse reaction by fixing carbon dioxide and water and creating glucose using the sun's energy, and provide the necessary oxygen for us consumers to use. Thus the notion that ultimately, on earth all energy came initially from the sun (except for nuclear energy, which we're not going into right now).
Ok, anyway back to the analogy. It turns out that in order to sustain a complex multicellular organism such as a mammal, it's obviously important to put some restrictions on cellular growth, because now, energy isn't limiting anymore in the extracellular milieu! As long as the organism has a reliable food source, all of its cells will just be bathed in cheap energy, ripe for the taking! Thus endocrine systems and layers upon layers of metabolic control have evolved in multicellular organisms to keep unrestrained cellular growth in check, lest cancer continuously break out. This allows for complex patterning and organ formation and super-specialization of cells, further dividing the labors of life and increasing the overall efficiency of the organism.
As such, humans can survive on remarkably little energy and other mammalian critters on even less. We can go an ENTIRE MONTH without food and still be viable. That's absolutely remarkable and it wouldn't be possible without these complex metabolic controls. And to boot, we have an incredibly long lifespan, as most biologists are coming to find that the price you pay for dealing with oxygen is cellular damage and senescence (aging).
So that's all great, except guess what, cancer cells, as you might have surmised, don't play by these rules. What Thompson and others have found is that they deliberately upregulate the early pathways in glucose metabolism (the only ones that primitive bacteria share with us), at the expense of the later pathways. In other words they suck down the glucose, extract a teeny bit of its energy extremely quickly, then dump their waste (lactic acid) in the extracellular milieu for someone else to deal with. This works great for them, cause they're mooching off all the cheap energy the body can provide (the concentration of glucose is tightly regulated by insulin), and they're really not contributing anything in return. It also allows them to quickly make more of the factories that make cellular proteins (ribosomes), which seems to be the rate limiting step in how quickly a cell can divide. What is worse, is that they continuously are dumping out a waste product that the liver eventually has to deal with to maintain the proper pH of the blood. And of course, that requires, you guessed it, more energy.
So, in the metastatic setting, you can see this quickly becomes an untenable relationship. The cancerous parasite is consuming an ever-larger share of the total energy supplies available to the body, what is worse, its unrestrained growth and invasive properties destroy the tightly patterned cellular architechture of vital organs (e.g. liver) that is absolutely critical to these organ's function. By compromising their ability to "clean up after the cancer's mess", more and more waste products build up, and less and less energy is available to sustain the vital organs of the body (e.g. the heart and the brain, of which the brain is absolutely dependent on glucose). You can see where this is going, an ever increasing, inexorable spiral to total organ failure and ultimately the demise of both the organism and of course the cancer as well.
If one believes in the scalability of biolgoical systems (ecosystems recapitulate the workings of organisms which recapitulate the workings of tissues and cells,etc.) and that they are fractal in nature, you would be very right in saying that the Earth's global organism is sensing that there's a cancer growing out of control, and maybe the recent natural disasters are manifestations of its "immune" system trying somewhat vainly to restrain it. Because we cancer resarchers also believe to some extent the human immune system eventually recognizes the cancer as foreign and also tries to attack it, it's just that the cells grow far too rapidly and are very resilient to attack. Plus they're genetically unstable and eventually through a combination of mutations may select for a new clone that is totally immune to the immune system. I don't know what the capabilities of the Earth's "immune system" are, but if human cancer is any guide, it's probably not enough.
On a phliosophical note, I also find it interesting how this is also playing out on an economic level, whereby the ultra-rich represent the cancerous tissue, consuming (or at least hoarding) more and more resources, and "mutating" the laws to make it legal to grab an ever bigger piece of the pie. The end result, of course, will be the same, total economic collapse, as the body politic will no longer be able to clean up after their mess, buy their products, or contribute to their labors, since they'll be totally devoid of resources.
Ah... well, it's all interconnected, isn't it?
FWIW, Thompson and others (such as my mentor's lab) believe that this reliance on easily-extracted energy and quick macromolecular synthesis may be the Achilles' heel of cancer. It certainly makes the cells very vulnerable to strategies that either downregulate these pathways or upregulate other regulatory pathways that put checks on these processes (my lab happens to study a protein that may just do that in relation to the ability of the cell to make new ribosomes). In fact, Thompson presented data that pretty convincingly shows that the reason some cheomtherapy agents are very effective is not that they damage DNA, per se, but rather that they trigger a cascade from the damaged DNA that ends up choking off the quick-energy pathway and forcing the cell to cannibalize itself. Normal cells aren't as reliant on the quick energy, so they're more than able to repair the DNA damage and get back to the status quo.
Of course the mutability of cancer cells will always be a problem, but if you simultaneously combine conventional chemo with newer agents that attack these pathways, you may see startling results. Just as combination antimicrobial(-viral) therapy has proven to be incredibly useful for drug-resistant TB and HIV (both of which have high mutation rates), perhaps someday we may be able to attack cancer with combination therapies that may at the least turn deadly cancers into managable diseases, and at the best, completely cure.
Now, if we could only get committments from the current administration to continue to fund the NIH, we'd all be set... :)