Proteasome inhibitors alter levels of intracellular peptides in HEK293T and SH-SY5Y cells

Sayani Dasgupta, Leandro M. Castro, Russell Dulman, Ciyu Yang, Marion Schmidt, Emer S. Ferro, Lloyd D. Fricker

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The proteasome cleaves intracellular proteins into peptides. Earlier studies found that treatment of human embryonic kidney 293T (HEK293T) cells with epoxomicin (an irreversible proteasome inhibitor) generally caused a decrease in levels of intracellular peptides. However, bortezomib (an antitumor drug and proteasome inhibitor) caused an unexpected increase in the levels of most intracellular peptides in HEK293T and SH-SY5Y cells. To address this apparent paradox, quantitative peptidomics was used to study the effect of a variety of other proteasome inhibitors on peptide levels in HEK293T and SH-SY5Y cells. Inhibitors tested included carfilzomib, MG132, MG262, MLN2238, AM114, and clasto-Lactacystin β-lactone. Only MG262 caused a substantial elevation in peptide levels that was comparable to the effect of bortezomib, although carfilzomib and MLN2238 elevated the levels of some peptides. To explore off-target effects, the proteosome inhibitors were tested with various cellular peptidases. Bortezomib did not inhibit tripeptidyl peptidase 2 and only weakly inhibited cellular aminopeptidase activity, as did some of the other proteasome inhibitors. However, potent inhibitors of tripeptidyl peptidase 2 (butabindide) and cellular aminopeptidases (bestatin) did not substantially alter the peptidome, indicating that the increase in peptide levels due to proteasome inhibitors is not a result of peptidase inhibition. Although we cannot exclude other possibilities, we presume that the paradoxical increase in peptide levels upon treatment with bortezomib and other inhibitors is the result of allosteric effects of these compounds on the proteasome. Because intracellular peptides are likely to be functional, it is possible that some of the physiologic effects of bortezomib and carfilzomib arise from the perturbation of peptide levels inside the cell.

Original languageEnglish (US)
Article numbere103604
JournalPLoS One
Volume9
Issue number7
DOIs
StatePublished - Jul 31 2014

Fingerprint

Proteasome Inhibitors
proteasome endopeptidase complex
kidneys
peptides
Kidney
Peptides
peptidases
cells
Aminopeptidases
aminopeptidases
Proteasome Endopeptidase Complex
Peptide Hydrolases
HEK293 Cells
Lactones
kidney cells
lactones
Antineoplastic Agents
Bortezomib
drugs

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Dasgupta, S., Castro, L. M., Dulman, R., Yang, C., Schmidt, M., Ferro, E. S., & Fricker, L. D. (2014). Proteasome inhibitors alter levels of intracellular peptides in HEK293T and SH-SY5Y cells. PLoS One, 9(7), [e103604]. https://doi.org/10.1371/journal.pone.0103604

Proteasome inhibitors alter levels of intracellular peptides in HEK293T and SH-SY5Y cells. / Dasgupta, Sayani; Castro, Leandro M.; Dulman, Russell; Yang, Ciyu; Schmidt, Marion; Ferro, Emer S.; Fricker, Lloyd D.

In: PLoS One, Vol. 9, No. 7, e103604, 31.07.2014.

Research output: Contribution to journalArticle

Dasgupta S, Castro LM, Dulman R, Yang C, Schmidt M, Ferro ES et al. Proteasome inhibitors alter levels of intracellular peptides in HEK293T and SH-SY5Y cells. PLoS One. 2014 Jul 31;9(7). e103604. https://doi.org/10.1371/journal.pone.0103604
Dasgupta, Sayani ; Castro, Leandro M. ; Dulman, Russell ; Yang, Ciyu ; Schmidt, Marion ; Ferro, Emer S. ; Fricker, Lloyd D. / Proteasome inhibitors alter levels of intracellular peptides in HEK293T and SH-SY5Y cells. In: PLoS One. 2014 ; Vol. 9, No. 7.
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