Molecular mechanisms of bortezomib resistant adenocarcinoma cells

Erika Suzuki, Susan Demo, Edgar Deu, Jonathan Keats, Shirin Arastu-Kapur, Peter Leif Bergsagel, Mark K. Bennett, Christopher J. Kirk

Research output: Contribution to journalArticle

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Abstract

Bortezomib (Velcade™) is a reversible proteasome inhibitor that is approved for the treatment of multiple myeloma (MM). Despite its demonstrated clinical success, some patients are deprived of treatment due to primary refractoriness or development of resistance during therapy. To investigate the role of the duration of proteasome inhibition in the anti-tumor response of bortezomib, we established clonal isolates of HT-29 adenocarcinoma cells adapted to continuous exposure of bortezomib. These cells were ~30-fold resistant to bortezomib. Two novel and distinct mutations in the β5 subunit, Cys63Phe, located distal to the binding site in a helix critical for drug binding, and Arg24Cys, found in the propeptide region were found in all resistant clones. The latter mutation is a natural variant found to be elevated in frequency in patients with MM. Proteasome activity and levels of both the constitutive and immunoproteasome were increased in resistant cells, which correlated to an increase in subunit gene expression. These changes correlated with a more rapid recovery of proteasome activity following brief exposure to bortezomib. Increased recovery rate was not due to increased proteasome turnover as similar findings were seen in cells co-treated with cycloheximide. When we exposed resistant cells to the irreversible proteasome inhibitor carfilzomib we noted a slower rate of recovery of proteasome activity as compared to bortezomib in both parental and resistant cells. Importantly, carfilzomib maintained its cytotoxic potential in the bortezomib resistant cell lines. Therefore, resistance to bortezomib, can be overcome with irreversible inhibitors, suggesting prolonged proteasome inhibition induces a more potent anti-tumor response.

Original languageEnglish (US)
Article numbere27996
JournalPLoS One
Volume6
Issue number12
DOIs
StatePublished - Dec 22 2011

Fingerprint

proteasome endopeptidase complex
adenocarcinoma
Adenocarcinoma
Proteasome Endopeptidase Complex
cells
myeloma
Proteasome Inhibitors
Multiple Myeloma
Recovery
Tumors
mutation
neoplasms
Bortezomib
HT29 Cells
Mutation
cycloheximide
Cycloheximide
Gene expression
binding sites
Neoplasms

ASJC Scopus subject areas

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

Cite this

Suzuki, E., Demo, S., Deu, E., Keats, J., Arastu-Kapur, S., Bergsagel, P. L., ... Kirk, C. J. (2011). Molecular mechanisms of bortezomib resistant adenocarcinoma cells. PLoS One, 6(12), [e27996]. https://doi.org/10.1371/journal.pone.0027996

Molecular mechanisms of bortezomib resistant adenocarcinoma cells. / Suzuki, Erika; Demo, Susan; Deu, Edgar; Keats, Jonathan; Arastu-Kapur, Shirin; Bergsagel, Peter Leif; Bennett, Mark K.; Kirk, Christopher J.

In: PLoS One, Vol. 6, No. 12, e27996, 22.12.2011.

Research output: Contribution to journalArticle

Suzuki, E, Demo, S, Deu, E, Keats, J, Arastu-Kapur, S, Bergsagel, PL, Bennett, MK & Kirk, CJ 2011, 'Molecular mechanisms of bortezomib resistant adenocarcinoma cells', PLoS One, vol. 6, no. 12, e27996. https://doi.org/10.1371/journal.pone.0027996
Suzuki, Erika ; Demo, Susan ; Deu, Edgar ; Keats, Jonathan ; Arastu-Kapur, Shirin ; Bergsagel, Peter Leif ; Bennett, Mark K. ; Kirk, Christopher J. / Molecular mechanisms of bortezomib resistant adenocarcinoma cells. In: PLoS One. 2011 ; Vol. 6, No. 12.
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