FTY720 analogues as sphingosine kinase 1 inhibitors: enzyme inhibition kinetics, allosterism, proteasomal degradation and actin rearrangement in MCF-7 breast cancer cells

Keng Lim, Francesca Romana Tonelli, Z. Li, X. Lu, R. Bittman, Susan Pyne, Nigel Pyne

Research output: Contribution to journalArticle

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Abstract

Sphingosine kinase 1 (SK1) catalyzes the conversion of sphingosine to the bioactive lipid sphingosine 1-phosphate. We have previously demonstrated that FTY720 and (S)-FTY720 vinylphosphonate are novel inhibitors of SK1 activity. Here, we show that (S)-FTY720 vinylphosphonate binds to a putative allosteric site in SK1 contingent on formation of the enzyme-sphingosine complex. We report that SK1 is an oligomeric protein (minimally a dimer) containing noncooperative catalytic sites and that the allosteric site exerts an autoinhibition of the catalytic site. A model is proposed in which (S)-FTY720 vinylphosphonate binding to and stabilization of the allosteric site might enhance the autoinhibitory effect on SK1 activity. Further evidence for the existence of allosteric site(s) in SK1 was demonstrated by data showing that two new FTY720 analogues (a conjugate of sphingosine with a fluorophore and (S)-FTY720 regioisomer) increased SK1 activity, suggesting relief of autoinhibition of SK1 activity. Comparisons with the SK1 inhibitor, SKi or siRNA knockdown of SK1 indicated that (S)-FTY720 vinylphosphonate and FTY720 behave as typical SK1 inhibitors in preventing sphingosine 1-phosphate-stimulated rearrangement of actin in MCF-7 cells. These findings are discussed in relation to the anticancer properties of SK1 inhibitors.

LanguageEnglish
Pages18633-18640
Number of pages8
JournalJournal of Biological Chemistry
Volume286
Issue number21
DOIs
Publication statusPublished - 27 May 2011

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Enzyme inhibition
Enzyme kinetics
Enzyme Inhibitors
Actins
Cells
Breast Neoplasms
Degradation
Allosteric Site
Sphingosine
Fingolimod Hydrochloride
sphingosine kinase
Catalytic Domain
Fluorophores
MCF-7 Cells
Dimers
Small Interfering RNA

Keywords

  • apoptosis
  • cytoskeleton
  • enzyme inhibitors
  • enzyme kinetics
  • sphingolipid

Cite this

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abstract = "Sphingosine kinase 1 (SK1) catalyzes the conversion of sphingosine to the bioactive lipid sphingosine 1-phosphate. We have previously demonstrated that FTY720 and (S)-FTY720 vinylphosphonate are novel inhibitors of SK1 activity. Here, we show that (S)-FTY720 vinylphosphonate binds to a putative allosteric site in SK1 contingent on formation of the enzyme-sphingosine complex. We report that SK1 is an oligomeric protein (minimally a dimer) containing noncooperative catalytic sites and that the allosteric site exerts an autoinhibition of the catalytic site. A model is proposed in which (S)-FTY720 vinylphosphonate binding to and stabilization of the allosteric site might enhance the autoinhibitory effect on SK1 activity. Further evidence for the existence of allosteric site(s) in SK1 was demonstrated by data showing that two new FTY720 analogues (a conjugate of sphingosine with a fluorophore and (S)-FTY720 regioisomer) increased SK1 activity, suggesting relief of autoinhibition of SK1 activity. Comparisons with the SK1 inhibitor, SKi or siRNA knockdown of SK1 indicated that (S)-FTY720 vinylphosphonate and FTY720 behave as typical SK1 inhibitors in preventing sphingosine 1-phosphate-stimulated rearrangement of actin in MCF-7 cells. These findings are discussed in relation to the anticancer properties of SK1 inhibitors.",
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FTY720 analogues as sphingosine kinase 1 inhibitors : enzyme inhibition kinetics, allosterism, proteasomal degradation and actin rearrangement in MCF-7 breast cancer cells. / Lim, Keng; Tonelli, Francesca Romana; Li, Z.; Lu, X.; Bittman, R.; Pyne, Susan; Pyne, Nigel.

In: Journal of Biological Chemistry, Vol. 286, No. 21, 27.05.2011, p. 18633-18640.

Research output: Contribution to journalArticle

TY - JOUR

T1 - FTY720 analogues as sphingosine kinase 1 inhibitors

T2 - Journal of Biological Chemistry

AU - Lim, Keng

AU - Tonelli, Francesca Romana

AU - Li, Z.

AU - Lu, X.

AU - Bittman, R.

AU - Pyne, Susan

AU - Pyne, Nigel

PY - 2011/5/27

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AB - Sphingosine kinase 1 (SK1) catalyzes the conversion of sphingosine to the bioactive lipid sphingosine 1-phosphate. We have previously demonstrated that FTY720 and (S)-FTY720 vinylphosphonate are novel inhibitors of SK1 activity. Here, we show that (S)-FTY720 vinylphosphonate binds to a putative allosteric site in SK1 contingent on formation of the enzyme-sphingosine complex. We report that SK1 is an oligomeric protein (minimally a dimer) containing noncooperative catalytic sites and that the allosteric site exerts an autoinhibition of the catalytic site. A model is proposed in which (S)-FTY720 vinylphosphonate binding to and stabilization of the allosteric site might enhance the autoinhibitory effect on SK1 activity. Further evidence for the existence of allosteric site(s) in SK1 was demonstrated by data showing that two new FTY720 analogues (a conjugate of sphingosine with a fluorophore and (S)-FTY720 regioisomer) increased SK1 activity, suggesting relief of autoinhibition of SK1 activity. Comparisons with the SK1 inhibitor, SKi or siRNA knockdown of SK1 indicated that (S)-FTY720 vinylphosphonate and FTY720 behave as typical SK1 inhibitors in preventing sphingosine 1-phosphate-stimulated rearrangement of actin in MCF-7 cells. These findings are discussed in relation to the anticancer properties of SK1 inhibitors.

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