Take the 2-minute tour ×
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It's 100% free, no registration required.

Has there ever been incidences of one or more cancerous cells having all it's cell-death pathways and apoptosis mechanisms intact and functional?

share|improve this question

2 Answers 2

up vote 4 down vote accepted

Usually the cell death mechanisms are overridden and therefore oncogenesis. The pathway components themselves are not mutated. One classical case I can cite is that of Ras-oncogene. See this article for details. Usually the survival/growth signals (MAP-kinase) are activated with simultaneous inactivation of apoptotic regulators (Akt-pathway). A mutation of MAP-kinase component ERK can also cause cancer but apoptosis is nonetheless supressed because of the interconnections of these tow pathways in the gene regulatory network.

Whereas in the case of tumor suppressors, the cause of cancer is genomic instability and failure to initiate apoptosis.

enter image description here

share|improve this answer

This is pretty unlikely, since one of the most important steps for cancer cells is to shut off apoptosis and proteins which control it (like p53, BCL2 and so on). Cancer cells (especially when they are genetically unstable) acquire so much mutations and misregulations, that these would otherwise trigger apoptosis which would result in the removal of the cell.

This can look like the following (figure taken from here), when you compare normal and cancer cell:

enter image description here

share|improve this answer
    
quite a complete figure.. i like it.. –  WYSIWYG Apr 30 at 10:52
    
Thanks. It is a slightly different perspective to your figure. –  Chris Apr 30 at 14:11
    
Does a pre-cancerous cell shut off apoptosis and the proteins that control it before it becomes a cancer cell or is it the case a cancer cell shuts off apoptosis mechanisms after it is already cancerous? –  user128932 May 1 at 2:00
    
Usually apoptosis is affected in a later stage of oncogenesis. However, in case of DNA damage induced oncogenesis, there is a failure to initiate apoptosis when the DNA is damaged and not repaired. In this case the signal has not yet reached the apoptotic pathway. This ensues genomic instability which may further lead to uncontrolled growth i.e cancer (as you can imagine, to grow and multiply maximally is the first instinct of any lifeform) –  WYSIWYG May 1 at 4:35

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.