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Linking the p53 tumour suppressor pathway to somatic cell reprogramming.

Kawamura T, Suzuki J, Wang YV, Menendez S, Morera LB, Raya A, Wahl GM, Izpisúa Belmonte JC - Nature (2009)

Bottom Line: We address both issues by investigating the mechanisms limiting reprogramming efficiency in somatic cells.Furthermore, silencing of p53 significantly increased the reprogramming efficiency of human somatic cells.These results provide insights into reprogramming mechanisms and suggest new routes to more efficient reprogramming while minimizing the use of oncogenes.

View Article: PubMed Central - PubMed

Affiliation: Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.

ABSTRACT
Reprogramming somatic cells to induced pluripotent stem (iPS) cells has been accomplished by expressing pluripotency factors and oncogenes, but the low frequency and tendency to induce malignant transformation compromise the clinical utility of this powerful approach. We address both issues by investigating the mechanisms limiting reprogramming efficiency in somatic cells. Here we show that reprogramming factors can activate the p53 (also known as Trp53 in mice, TP53 in humans) pathway. Reducing signalling to p53 by expressing a mutated version of one of its negative regulators, by deleting or knocking down p53 or its target gene, p21 (also known as Cdkn1a), or by antagonizing reprogramming-induced apoptosis in mouse fibroblasts increases reprogramming efficiency. Notably, decreasing p53 protein levels enabled fibroblasts to give rise to iPS cells capable of generating germline-transmitting chimaeric mice using only Oct4 (also known as Pou5f1) and Sox2. Furthermore, silencing of p53 significantly increased the reprogramming efficiency of human somatic cells. These results provide insights into reprogramming mechanisms and suggest new routes to more efficient reprogramming while minimizing the use of oncogenes.

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Related in: MedlinePlus

Modulation of p53 activity alters reprogramming efficiency(a) and (b) Fold change in the number of 3F induced Nanog-positive colonies by Arf shRNA or by Arf/Ink4a shRNA compared to control shRNA (n=3). Protein knockdown efficiency was examined by western blot. (c) 3F induced Nanog-positive colonies from wild type (+/+) and homozygous (3SA/3SA) MEFs (n=3).
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Figure 2: Modulation of p53 activity alters reprogramming efficiency(a) and (b) Fold change in the number of 3F induced Nanog-positive colonies by Arf shRNA or by Arf/Ink4a shRNA compared to control shRNA (n=3). Protein knockdown efficiency was examined by western blot. (c) 3F induced Nanog-positive colonies from wild type (+/+) and homozygous (3SA/3SA) MEFs (n=3).

Mentions: The ability of the 3F to increase p53 abundance suggests that controlling its stability might be crucial for p53-mediated reprogramming suppression. Thus we determined whether reducing Arf levels using Arf shRNA increases reprogramming efficiency, as lower Arf levels should decrease p53 stability16–18. Reducing Arf levels by 2–4 fold (Fig. 2a) engendered an approximately 2-fold increase in 3F reprogramming (Fig. 2a). Reducing Arf and p16Ink4a together increased iPS cell formation even more than Arf alone (4–5 fold, Fig. 2b), indicating that compromising retinoblastoma (Rb) tumor suppressor19 function by antagonizing p16Ink4a can collaborate with diminished p53 activity to improve reprogramming efficiency.


Linking the p53 tumour suppressor pathway to somatic cell reprogramming.

Kawamura T, Suzuki J, Wang YV, Menendez S, Morera LB, Raya A, Wahl GM, Izpisúa Belmonte JC - Nature (2009)

Modulation of p53 activity alters reprogramming efficiency(a) and (b) Fold change in the number of 3F induced Nanog-positive colonies by Arf shRNA or by Arf/Ink4a shRNA compared to control shRNA (n=3). Protein knockdown efficiency was examined by western blot. (c) 3F induced Nanog-positive colonies from wild type (+/+) and homozygous (3SA/3SA) MEFs (n=3).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2735889&req=5

Figure 2: Modulation of p53 activity alters reprogramming efficiency(a) and (b) Fold change in the number of 3F induced Nanog-positive colonies by Arf shRNA or by Arf/Ink4a shRNA compared to control shRNA (n=3). Protein knockdown efficiency was examined by western blot. (c) 3F induced Nanog-positive colonies from wild type (+/+) and homozygous (3SA/3SA) MEFs (n=3).
Mentions: The ability of the 3F to increase p53 abundance suggests that controlling its stability might be crucial for p53-mediated reprogramming suppression. Thus we determined whether reducing Arf levels using Arf shRNA increases reprogramming efficiency, as lower Arf levels should decrease p53 stability16–18. Reducing Arf levels by 2–4 fold (Fig. 2a) engendered an approximately 2-fold increase in 3F reprogramming (Fig. 2a). Reducing Arf and p16Ink4a together increased iPS cell formation even more than Arf alone (4–5 fold, Fig. 2b), indicating that compromising retinoblastoma (Rb) tumor suppressor19 function by antagonizing p16Ink4a can collaborate with diminished p53 activity to improve reprogramming efficiency.

Bottom Line: We address both issues by investigating the mechanisms limiting reprogramming efficiency in somatic cells.Furthermore, silencing of p53 significantly increased the reprogramming efficiency of human somatic cells.These results provide insights into reprogramming mechanisms and suggest new routes to more efficient reprogramming while minimizing the use of oncogenes.

View Article: PubMed Central - PubMed

Affiliation: Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.

ABSTRACT
Reprogramming somatic cells to induced pluripotent stem (iPS) cells has been accomplished by expressing pluripotency factors and oncogenes, but the low frequency and tendency to induce malignant transformation compromise the clinical utility of this powerful approach. We address both issues by investigating the mechanisms limiting reprogramming efficiency in somatic cells. Here we show that reprogramming factors can activate the p53 (also known as Trp53 in mice, TP53 in humans) pathway. Reducing signalling to p53 by expressing a mutated version of one of its negative regulators, by deleting or knocking down p53 or its target gene, p21 (also known as Cdkn1a), or by antagonizing reprogramming-induced apoptosis in mouse fibroblasts increases reprogramming efficiency. Notably, decreasing p53 protein levels enabled fibroblasts to give rise to iPS cells capable of generating germline-transmitting chimaeric mice using only Oct4 (also known as Pou5f1) and Sox2. Furthermore, silencing of p53 significantly increased the reprogramming efficiency of human somatic cells. These results provide insights into reprogramming mechanisms and suggest new routes to more efficient reprogramming while minimizing the use of oncogenes.

Show MeSH
Related in: MedlinePlus