Growth arrest, permanent

CHO cells, also show a lower sensitivity to bleomycin (Lopez-Larraza et al, 2006). The ATC-15 cells exhibit satisfactory growth at bleomycin doses that produce a permanent growth arrest of CHO cells, thereby suggesting that mosquito cells might have linker DNA shorter than that of mammalian cells. 

If dividing mammalian cells are exposed to higher concentrations of H2O2 than those that cause temporary growth-arrest and transient adaptation, they can be forced into a permanently growth-arrested state (Scheme 2). Thus, cells exposed to H2O2 concentrations of 250-400 pM,or 9-14 pmol 10 cells, will never divide again [15]. 

Saveli, J. et al.. Permanent growth arrest in irradiated human fibroblasts, 155,... 

Owing to the importance of these molecular switches, their misregulation often results in proteins that are permanently arrested in the GTP-bound state, and thus they are continuously sending proliferation signals that result in uncontrolled cell growth and ultimately in cancer. This is the case of Ras proteins, important oncogens found mutated in around 30% of all cancers and up to 90% in pancreatic, lung, or colorectal cancer. 

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