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Cordycepin inhibits protein synthesis and cell adhesion through effects on signal transduction.

Wong YY, Moon A, Duffin R, Barthet-Barateig A, Meijer HA, Clemens MJ, de Moor CH - J. Biol. Chem. (2009)

Bottom Line: In 4EBP knock-out cells, the effect of cordycepin on translation is strongly reduced, confirming the role of this modification.Inhibition of AMPK prevented translation repression by cordycepin and abolished 4EBP1 dephosphorylation, indicating that the effect of cordycepin on mTOR signaling and protein synthesis is mediated by AMPK activation.We conclude that many of the reported biological effects of cordycepin are likely to be due to its effects on mTOR and AMPK signaling.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.

ABSTRACT
3'-Deoxyadenosine, also known as cordycepin, is a known polyadenylation inhibitor with a large spectrum of biological activities, including anti-proliferative, pro-apoptotic and anti-inflammatory effects. In this study we confirm that cordycepin reduces the length of poly(A) tails, with some mRNAs being much more sensitive than others. The low doses of cordycepin that cause poly(A) changes also reduce the proliferation of NIH3T3 fibroblasts. At higher doses of the drug we observed inhibition of cell attachment and a reduction of focal adhesions. Furthermore, we observed a strong inhibition of total protein synthesis that correlates with an inhibition of mammalian target of rapamycin (mTOR) signaling, as observed by reductions in Akt kinase and 4E-binding protein (4EBP) phosphorylation. In 4EBP knock-out cells, the effect of cordycepin on translation is strongly reduced, confirming the role of this modification. In addition, the AMP-activated kinase (AMPK) was shown to be activated. Inhibition of AMPK prevented translation repression by cordycepin and abolished 4EBP1 dephosphorylation, indicating that the effect of cordycepin on mTOR signaling and protein synthesis is mediated by AMPK activation. We conclude that many of the reported biological effects of cordycepin are likely to be due to its effects on mTOR and AMPK signaling.

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Protein synthesis in murine embryonic fibroblasts lacking 4EBP expression or containing non-phosphorylatable eIF2α is resistant to cordycepin. Protein synthesis in MEFs from animals lacking expression of 4EBP1 and 4EBP2 (double knock-out, DKO) (A) and MEFs from animals with the S51A mutation in eIF2α (B), and their corresponding wild-type controls, was measured by [35S]methionine incorporation into protein. The cells were pre-treated with 0, 50, and 200 μm cordycepin for 1.5 h and then labeled for 1 h. The data are corrected for total protein concentration and are shown as the means ± S.E. of three replicates for each treatment.
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Figure 6: Protein synthesis in murine embryonic fibroblasts lacking 4EBP expression or containing non-phosphorylatable eIF2α is resistant to cordycepin. Protein synthesis in MEFs from animals lacking expression of 4EBP1 and 4EBP2 (double knock-out, DKO) (A) and MEFs from animals with the S51A mutation in eIF2α (B), and their corresponding wild-type controls, was measured by [35S]methionine incorporation into protein. The cells were pre-treated with 0, 50, and 200 μm cordycepin for 1.5 h and then labeled for 1 h. The data are corrected for total protein concentration and are shown as the means ± S.E. of three replicates for each treatment.

Mentions: To determine the relative importance of 4EBP dephosphorylation and eIF2α phosphorylation for the inhibition of protein synthesis by cordycepin, we employed mutant mouse embryo fibroblasts in which either Ser51 of eIF2α was replaced by Ala (S51A cells) (23) or in which the genes for 4EBP1 and 4EBP2 were disrupted (24). As can be seen in Fig. 6, both mutant cell lines showed some resistance to cordycepin, compared with their corresponding wild-type controls. The reduced sensitivity to the inhibitor was particularly marked in the 4EBP double knock-out cells, suggesting that 4EBP dephosphorylation is an important mechanism by which cordycepin inhibits translation.


Cordycepin inhibits protein synthesis and cell adhesion through effects on signal transduction.

Wong YY, Moon A, Duffin R, Barthet-Barateig A, Meijer HA, Clemens MJ, de Moor CH - J. Biol. Chem. (2009)

Protein synthesis in murine embryonic fibroblasts lacking 4EBP expression or containing non-phosphorylatable eIF2α is resistant to cordycepin. Protein synthesis in MEFs from animals lacking expression of 4EBP1 and 4EBP2 (double knock-out, DKO) (A) and MEFs from animals with the S51A mutation in eIF2α (B), and their corresponding wild-type controls, was measured by [35S]methionine incorporation into protein. The cells were pre-treated with 0, 50, and 200 μm cordycepin for 1.5 h and then labeled for 1 h. The data are corrected for total protein concentration and are shown as the means ± S.E. of three replicates for each treatment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807318&req=5

Figure 6: Protein synthesis in murine embryonic fibroblasts lacking 4EBP expression or containing non-phosphorylatable eIF2α is resistant to cordycepin. Protein synthesis in MEFs from animals lacking expression of 4EBP1 and 4EBP2 (double knock-out, DKO) (A) and MEFs from animals with the S51A mutation in eIF2α (B), and their corresponding wild-type controls, was measured by [35S]methionine incorporation into protein. The cells were pre-treated with 0, 50, and 200 μm cordycepin for 1.5 h and then labeled for 1 h. The data are corrected for total protein concentration and are shown as the means ± S.E. of three replicates for each treatment.
Mentions: To determine the relative importance of 4EBP dephosphorylation and eIF2α phosphorylation for the inhibition of protein synthesis by cordycepin, we employed mutant mouse embryo fibroblasts in which either Ser51 of eIF2α was replaced by Ala (S51A cells) (23) or in which the genes for 4EBP1 and 4EBP2 were disrupted (24). As can be seen in Fig. 6, both mutant cell lines showed some resistance to cordycepin, compared with their corresponding wild-type controls. The reduced sensitivity to the inhibitor was particularly marked in the 4EBP double knock-out cells, suggesting that 4EBP dephosphorylation is an important mechanism by which cordycepin inhibits translation.

Bottom Line: In 4EBP knock-out cells, the effect of cordycepin on translation is strongly reduced, confirming the role of this modification.Inhibition of AMPK prevented translation repression by cordycepin and abolished 4EBP1 dephosphorylation, indicating that the effect of cordycepin on mTOR signaling and protein synthesis is mediated by AMPK activation.We conclude that many of the reported biological effects of cordycepin are likely to be due to its effects on mTOR and AMPK signaling.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.

ABSTRACT
3'-Deoxyadenosine, also known as cordycepin, is a known polyadenylation inhibitor with a large spectrum of biological activities, including anti-proliferative, pro-apoptotic and anti-inflammatory effects. In this study we confirm that cordycepin reduces the length of poly(A) tails, with some mRNAs being much more sensitive than others. The low doses of cordycepin that cause poly(A) changes also reduce the proliferation of NIH3T3 fibroblasts. At higher doses of the drug we observed inhibition of cell attachment and a reduction of focal adhesions. Furthermore, we observed a strong inhibition of total protein synthesis that correlates with an inhibition of mammalian target of rapamycin (mTOR) signaling, as observed by reductions in Akt kinase and 4E-binding protein (4EBP) phosphorylation. In 4EBP knock-out cells, the effect of cordycepin on translation is strongly reduced, confirming the role of this modification. In addition, the AMP-activated kinase (AMPK) was shown to be activated. Inhibition of AMPK prevented translation repression by cordycepin and abolished 4EBP1 dephosphorylation, indicating that the effect of cordycepin on mTOR signaling and protein synthesis is mediated by AMPK activation. We conclude that many of the reported biological effects of cordycepin are likely to be due to its effects on mTOR and AMPK signaling.

Show MeSH
Related in: MedlinePlus