Combined effects of the proteasome inhibitor bortezomib and Hsp70 inhibitors on the B16F10 melanoma cell line

  • Authors:
    • Azmi Yerlikaya
    • Emrah Okur
    • Semih Şeker
    • Nuray Erin
  • View Affiliations

  • Published online on: March 1, 2010     https://doi.org/10.3892/mmr_00000262
  • Pages: 333-339
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Abstract

Studies have shown that the 26S proteasome is involved in cell cycle control, transcription, DNA repair, immune response and protein synthesis. In the present study, we investigated the antiproliferative effects of the proteasome inhibitor bortezomib and heat shock protein (Hsp)70 inhibitors on the B16F10 melanoma cell line. The IC50 value of bortezomib was found to be 2.46 nM, while that of the Hsp70 inhibitor quercetin was 45 µM in the B16F10 cells. This indicates that bortezomib is more effective than quercetin in inhibiting cell growth. In response to treatment with 10 nM bortezomib for 24 h, cells underwent rounding, shrinkage and detachment. Unexpectedly, such morphological changes were not observed in cells treated with 20 µM quercetin alone, nor in cells treated with bortezomib + quercetin, indicating that quercetin inhibited the cytotoxic effects of bortezomib. Quantitation of cell viability also indicated that quercetin interfered with the cytotoxic effects of bortezomib. However, the combination of quercetin with another proteasome inhibitor, MG132, caused significant cell death as compared to single-agent treatment. A DNA ladder assay also confirmed the inhibitory effect of quercetin on the apoptosis-inducing effect of bortezomib. However, quercetin did not prevent the induction of apoptosis by MG132; on the contrary, it potentiated the apoptosis-inducing effect of MG132. These results suggest that the combination of quercetin with clinically beneficial proteasome inhibitors (except bortezomib) may have increased efficacy in the treatment of cancer. We also tested the combination of two other Hsp70 inhibitors, KNK-437 and schisandrin-B, in combination with bortezomib. Neither of these combinations was more effective than single-agent treatment.

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March-April 2010
Volume 3 Issue 2

Print ISSN: 1791-2997
Online ISSN:1791-3004

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Spandidos Publications style
Yerlikaya A, Okur E, Şeker S and Erin N: Combined effects of the proteasome inhibitor bortezomib and Hsp70 inhibitors on the B16F10 melanoma cell line . Mol Med Rep 3: 333-339, 2010.
APA
Yerlikaya, A., Okur, E., Şeker, S., & Erin, N. (2010). Combined effects of the proteasome inhibitor bortezomib and Hsp70 inhibitors on the B16F10 melanoma cell line . Molecular Medicine Reports, 3, 333-339. https://doi.org/10.3892/mmr_00000262
MLA
Yerlikaya, A., Okur, E., Şeker, S., Erin, N."Combined effects of the proteasome inhibitor bortezomib and Hsp70 inhibitors on the B16F10 melanoma cell line ". Molecular Medicine Reports 3.2 (2010): 333-339.
Chicago
Yerlikaya, A., Okur, E., Şeker, S., Erin, N."Combined effects of the proteasome inhibitor bortezomib and Hsp70 inhibitors on the B16F10 melanoma cell line ". Molecular Medicine Reports 3, no. 2 (2010): 333-339. https://doi.org/10.3892/mmr_00000262