Autophagy and cancer

This is a new cellular mechanism I did not know about: autophagy. Nature's issue of April 12th (I am bit behind I know) has an interesting article in the section Q&A on autophagy and its role in cancer.

Autophagy is the process by which cells degrade faulty or redundant components. It is used by cells when they need to reuse molecules for other uses and also it plays an important role in complementing apoptosis. Both apoptosis and autophagy are connected to cell death but in the case of autophagy cell death is not always the outcome although it can be a substitute when the apoptotic mechanism is crippled. In that case the cell literally eats itself to death.

The image bellow comes from the article. Autophagy has the potential of being useful for cancer supression but also for cancer promotion. The balance is important, too little and you get cell death when the cell cannot produce things it needs by reusing parts of itself. Too much of it and you also get cell death since the cell can eat itself. Altering this balance in a tumour cell could be the source of a new therapy although as usual it is important to remember that cells might evolve mechanisms to avoid the trouble of autophagy, maybe by inactivating the atophagy mechanism all together. Even in that case the tumour cell would be less capable of surviving in situations of stress since it would not be able to recycle material.

Autophagy seems to be a mechanism whose precise role in cancer has not been fully studied yet but could be a promising extra target for a multi target therapy that could hinder cancer evolution and growth.

Genes and cancer

I start the week with a post about something really exciting that I read in Science. Unfortunately my institution does not have access to articles in Science published online before they have been printed on paper so I had to be satisfied for the time being with the reports pusblished by conventional media like the Washington Post.

It seems that researchers have screened for and found 189 genes that are altered in colon and breast cancers. Although we are talking about only two types of cancer, breast and colon cancer are two of the most diagnosed cancers in the western hemisphere. It is remarkable that both types of cancer share very few cancer-related genes and that most of the genes discovered to have a role in these cancers have not been known to be so before.

Tumour supressor gene and aging

Read at the NYT: Researchers at the universities of North Carolina, Michigan and Harvard have found that p16 gradually inhibits the proliferation capabilities of stem cells when they reach certain age. The mechanism is useful to prevent the proliferation of cells that, due to their age, have a significantly increased probability of creating tumours.

The paper reporting the research will be published in Nature. One interesting comment by one of the authors is that in his opinion aging is not random but an anticancer mechanism. I find this observation plausible but having an interest in evolution I cannot help thinking that the reason for aging could also be that once an organism has fulfilled its replication duties, its evolutionary-shaped genetic program does not care much for the long term survival of the individual. In other words, evolution does not favour individuals who are good at surviving for ever but that are good at surviving for long enough as to have lots of equally successful offspring.