Rejuvenation and Cancer
Rejuvenation and Cancer
It is obvious that any mechanism which has the power to rejuvenate or regenerate a system has also the power to destroy it: if the regeneration process goes wrong, and something different is generated instead of the original system, then the consequences are very severe.
Cancer itself is like uncontrolled "rejuvenation" in an organism: "rejuvenation" went awry. Like stem cells or embryonic cells, cancer cells do not age and can proliferate without limits. Cancer cells and small tumors influence their environment to increase local blood supply and they suppress the maternal immune system, just like embryos. Cancer cells act like embryonic cells, who proliferate vigorously, are capable of extensive migration, and secrete factors that increase the local supply of blood. In general one can find many similarities, tumor cells may grow and spread by exploiting the genetic programs normally active only during embryonic and fetal development :
- Tumor originating cells (cancer stem cells) are like stem cells
- Tumors themselves are like embryos
- Tumor development resembles embryonic and fetal development
If there is indeed a close link between rejuvenation and cancer, then the consequences would be severe: suppressing tumor promoting proteins would prevent them from doing needed repair work, i.e. suppressing cancer may increase aging processes, while rejuvenating drugs which replace and repair damaged or senescent tissues would increase the risk of cancer.
Self-renewal and Stem Cells
Self-renewal is the key property of stem cells. They are fundamental for organ development and tissue repair. Although they belong to the most beneficial cells and enable rejuvenation and regeneration of the body, they also seem to be at the heart of every tumor, as new research about cancer stem cells has found out. Cancer cells and stem cells are disturbingly similar . Is it possible that the same cells which are responsible for maintaining a tissue or an organ are also responsible for destroying it through the worst form of disease?
A link between self-renewal, self-rejuvenation and self-reproduction would perhaps explain why cancer is most common in the organs responsible for self-reproduction: breast cancer or endometrial cancer in women, and prostate cancer in men. It would also explain why “many of the body’s tissues that are most prone to cancer, like the blood, skin and lining of the gut” are self-regenerating tissues. These self-regenerating tissues are composed of short-lived cells, and contain a self-renewing population of stem cells that maintain them.
Cancer is a very complex disease. It can take years and decades until enough mutations and damages are accumulated to enable a tumor. One problem is that every tumor looks different. Future research will hopefully shed more light on this complicated topic. Recent research has found a close relationship between stem cells and tumor generating cancer cells. Tumors seem to be the price for high age. The reason is not only accumulated damage in form of progressive deterioration, gradual abraison and inevitable wear and tear damages. Old age is only possible through rejuvenation and repair. It looks like stem cells which are responsible for renewal, rejuvenation and regeneration have not only the ability to regenerate a system, but also the possibility to destroy a system.
The more specialized an organism or a cell is, the more it seems to loose its ability to replicate and regenerate itself. Stem cells are primal undifferentiated cells that retain the ability to produce an identical copy of themselves, whereas ordinary cells, specialized for a certain purpose, loose the ability to produce an identical copy of themselves. Intermediary cells are restricted by an internal counting mechanism to a finite number of cell divisions, which declines with increasing differentiation.
Has this something to do with the unique history of each organism or cell (are old, highly differentiated and specialized cells usually polluted or used up) ? Or is this hierarchy useful for avoiding chaos and confusing which could arise if every cell would be allowed to replicate itself? If no cells would be able to copy and replicate itself, then the body would not be able to rejuvenate and repair itself in order to replace damaged or old cells. If all cells would be able to do this, this would result in ”chaos” and every cell would be a potential cancer cell. It looks like Nature has invented a compromise in form of stem cells. Stem cells are a blessing, because they can replace damaged or old cells, but mutated or damaged stem cells are a curse. Stem cells have like tumor generating cancer cells the same potential to proliferate, they have an unlimited life span and the ability to generate a diverse range of other cell types.
New research gives strong evidence that cancer is the price for an evolvable system (subject to mutation) with the ability of self-replication, self-rejuvenation, self-regeneration and self-repair. It seems to be the price for the self-* properties which enable our existence and keep us alive. Perhaps this helps to explain why it is so difficult to find a cure for it. Recently, researchers have suggest again new strategies to fight cancer, for instance viruses (modified common cold viruses), chillies (spicy food) or sugars (a combination of sugar and short-chain fatty acid). So far, there is no miracle cure for cancer. And probably none of these new approaches will be a miracle cure, either. But hopefully one approach in the future - perhaps due to the new insight that the disease is related to self-rejuvenation - will lead to something useful in the ongoing battle against this terrible disease.
Cancer in CAS
This rises the urgent question if artificial systems can develop some form of cancer, too, if we try to build systems with these very desirable self-* properties. Is there a form of cancer in complex adaptive systems in general, not only in biological organisms, but also in ecological, economical, social or political systems ? This would perhaps be an element arising from the need for self-rejuvenation which proliferates, spreads and replicates itself until it has destroyed the whole system. Joseph Schumpeter introduced a similar idea of creative destruction in the context of capitalism. Creative destruction means one thing is replaced by another from within.
- Ecologies systems allow the self-rejuvenation by “granting the right” to create new species and to explore new ways to survive. In an ecological system, this freedom can lead to mass extinctions or epidemics caused by parasites or viruses with the capacity to damage or destroy the whole ecological system.
- Economies allow the self-rejuvenation by granting the right to found new companies and to explore new market forms. In an economical system, this freedom can lead to market monopolies, which destroy the market system. Or it can lead to disruptive innovations which destroy a large number of existing companies by creative destruction
- Democracies allow the self-rejuvenation by granting the rights to found new parties, to assemble, to demonstrate, and to educate. In a political system, this can lead to terrorism or an ideology like fascism. In a religious system, it can lead to schisms and sects.
- Science allows the self-rejuvenation by “granting the right” to create new theories and to explore new ways to explain nature. This freedom can lead to subsystems with the capacity to threaten the whole scientific system, for example in form of a paradigm shift.
In a 1995 essay "Eternal Fascism", Umberto Eco attempts to list general properties of fascist ideology. One could add "lack of differentiation", "uncontrolled growth" beyond the normal limits, invasion of adjacent systems, and generally "malignant, aggressive and egoistic behavior" to the list - the hallmarks of cancer. Fascism is a bit like cancer for politics. The political system allows the self-rejuvenation by granting the rights to demonstrate and to found new parties. This can lead to an ideology like fascism, which spreads and growths like cancer, and eventually destroys the old system completely. Cancer is the result of a self-renewal or self-rejuvenation which has gone wrong. It is a bit like the evolution of an ancient or alien life form inside of the own system which is normally prohibited, and cancer development is a remarkably similar to the process of embryonic development and evolution itself.
In general, if a complex adaptive system has a built-in self-rejuvenation ability, and it grants it’s agents the rights to create and to found new elements, these elements can severely damage or threaten the function of the whole system. Any system which is able to remould and reinvent itself can replace itself by something else.