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Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation

Lasonolide A (LSA), a potent antitumor polyketide from the marine sponge, Forcepia sp., induces rapid and reversible protein hyperphosphorylation and premature chromosome condensation (PCC) at nanomolar concentrations independent of cyclin-dependent kinases. To identify cellular targets of LSA, we s...

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Autores principales: Jossé, Rozenn, Zhang, Yong-Wei, Giroux, Valentin, Ghosh, Arun K., Luo, Ji, Pommier, Yves
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483648/
https://www.ncbi.nlm.nih.gov/pubmed/26058013
http://dx.doi.org/10.3390/md13063625
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author Jossé, Rozenn
Zhang, Yong-Wei
Giroux, Valentin
Ghosh, Arun K.
Luo, Ji
Pommier, Yves
author_facet Jossé, Rozenn
Zhang, Yong-Wei
Giroux, Valentin
Ghosh, Arun K.
Luo, Ji
Pommier, Yves
author_sort Jossé, Rozenn
collection PubMed
description Lasonolide A (LSA), a potent antitumor polyketide from the marine sponge, Forcepia sp., induces rapid and reversible protein hyperphosphorylation and premature chromosome condensation (PCC) at nanomolar concentrations independent of cyclin-dependent kinases. To identify cellular targets of LSA, we screened 2951 shRNAs targeting a pool of human kinases and phosphatases (1140 RefSeqs) to identify genes that modulate PCC in response to LSA. This led to the identification of RAF1 (C-RAF) as a mediator of LSA-induced PCC, as shRNAs against RAF1 conferred resistance to LSA. We found that LSA induced RAF1 phosphorylation on Serine 338 within minutes in human colorectal carcinoma HCT-116, ovarian carcinoma OVCAR-8, and Burkitt’s lymphoma CA46 cell lines. RAF1 depletion by siRNAs attenuated LSA-induced PCC in HCT-116 and OVCAR-8 cells. Furthermore, mouse embryonic fibroblasts (MEF) with homozygous deletion in Raf1, but not deletion in the related kinase Braf, were resistant to LSA-induced PCC. Complementation of Raf1(−/−) MEFs with wild-type human RAF1, but not with kinase-dead RAF1 mutant, restored LSA-induced PCC. Finally, the Raf inhibitor sorafenib, but not the MEK inhibitor AZD6244, effectively suppressed LSA-induced PCC. Our findings implicate a previously unknown, MAPK-independent role of RAF1 in chromatin condensation and potent activation of this pathway by LSA.
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spelling pubmed-44836482015-06-30 Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation Jossé, Rozenn Zhang, Yong-Wei Giroux, Valentin Ghosh, Arun K. Luo, Ji Pommier, Yves Mar Drugs Article Lasonolide A (LSA), a potent antitumor polyketide from the marine sponge, Forcepia sp., induces rapid and reversible protein hyperphosphorylation and premature chromosome condensation (PCC) at nanomolar concentrations independent of cyclin-dependent kinases. To identify cellular targets of LSA, we screened 2951 shRNAs targeting a pool of human kinases and phosphatases (1140 RefSeqs) to identify genes that modulate PCC in response to LSA. This led to the identification of RAF1 (C-RAF) as a mediator of LSA-induced PCC, as shRNAs against RAF1 conferred resistance to LSA. We found that LSA induced RAF1 phosphorylation on Serine 338 within minutes in human colorectal carcinoma HCT-116, ovarian carcinoma OVCAR-8, and Burkitt’s lymphoma CA46 cell lines. RAF1 depletion by siRNAs attenuated LSA-induced PCC in HCT-116 and OVCAR-8 cells. Furthermore, mouse embryonic fibroblasts (MEF) with homozygous deletion in Raf1, but not deletion in the related kinase Braf, were resistant to LSA-induced PCC. Complementation of Raf1(−/−) MEFs with wild-type human RAF1, but not with kinase-dead RAF1 mutant, restored LSA-induced PCC. Finally, the Raf inhibitor sorafenib, but not the MEK inhibitor AZD6244, effectively suppressed LSA-induced PCC. Our findings implicate a previously unknown, MAPK-independent role of RAF1 in chromatin condensation and potent activation of this pathway by LSA. MDPI 2015-06-05 /pmc/articles/PMC4483648/ /pubmed/26058013 http://dx.doi.org/10.3390/md13063625 Text en © 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jossé, Rozenn
Zhang, Yong-Wei
Giroux, Valentin
Ghosh, Arun K.
Luo, Ji
Pommier, Yves
Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation
title Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation
title_full Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation
title_fullStr Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation
title_full_unstemmed Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation
title_short Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation
title_sort activation of raf1 (c-raf) by the marine alkaloid lasonolide a induces rapid premature chromosome condensation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483648/
https://www.ncbi.nlm.nih.gov/pubmed/26058013
http://dx.doi.org/10.3390/md13063625
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