Effect of the proteasome inhibitor ALLnL on cisplatin sensitivity in human ovarian tumor cells

  • Authors:
    • Manasses K. Yunmbam
    • Qingdi Q. Li
    • Edward G. Mimnaugh
    • Ganesh L. Kayastha
    • Jing J. Yu
    • Lawana N. Jones
    • Len Neckers
    • Eddie Reed
  • View Affiliations

  • Published online on: October 1, 2001     https://doi.org/10.3892/ijo.19.4.741
  • Pages: 741-748
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Abstract

Small molecules suppressing proteasome function inhibit the post-translational ubiquitination of selected proteins. Ubiquitin H2A is an example of an abundant chromatin-associated protein that is known to be ubiquitinated, which is important for several proteins involved in the repair of DNA damage. We therefore studied the effect of the proteasome inhibitor, N-acetyl leucyl-leucyl norlucinal (ALLnL), on cisplatin sensitivity in three human ovarian tumor cell lines. The proteasome inhibitor ALLnL was administered for 4 h before cells were subsequently exposed to cisplatin for 1 h. Our results showed that ALLnL, at its respective IC20 concentration, increased cellular sensitivity to cisplatin in an additive manner in human ovarian cancer A2780, A2780/CP70, and OVCAR3 cells. We also demonstrated that ALLnL caused a 50% increase in total cellular accumulation of cisplatin, and reduced the rate of cisplatin efflux by about 50%. In addition, DNA damage levels were increased after ALLnL treatment. By contrast, DNA repair was inhibited 2 to 3-fold in ALLnL-pretreated cells, as compared to the controls. Furthermore, our study showed that ALLnL deubiquitinated nucleosomal histone H2A in these cells in a concentration-dependent fashion, as assessed by Western blot analysis. These data suggest that sublethal levels of exposure to agents that inhibit proteasome function may alter the subcellular pharmacology of platinum in human ovarian carcinoma cells.

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October 2001
Volume 19 Issue 4

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Spandidos Publications style
Yunmbam MK, Li QQ, Mimnaugh EG, Kayastha GL, Yu JJ, Jones LN, Neckers L and Reed E: Effect of the proteasome inhibitor ALLnL on cisplatin sensitivity in human ovarian tumor cells. Int J Oncol 19: 741-748, 2001
APA
Yunmbam, M.K., Li, Q.Q., Mimnaugh, E.G., Kayastha, G.L., Yu, J.J., Jones, L.N. ... Reed, E. (2001). Effect of the proteasome inhibitor ALLnL on cisplatin sensitivity in human ovarian tumor cells. International Journal of Oncology, 19, 741-748. https://doi.org/10.3892/ijo.19.4.741
MLA
Yunmbam, M. K., Li, Q. Q., Mimnaugh, E. G., Kayastha, G. L., Yu, J. J., Jones, L. N., Neckers, L., Reed, E."Effect of the proteasome inhibitor ALLnL on cisplatin sensitivity in human ovarian tumor cells". International Journal of Oncology 19.4 (2001): 741-748.
Chicago
Yunmbam, M. K., Li, Q. Q., Mimnaugh, E. G., Kayastha, G. L., Yu, J. J., Jones, L. N., Neckers, L., Reed, E."Effect of the proteasome inhibitor ALLnL on cisplatin sensitivity in human ovarian tumor cells". International Journal of Oncology 19, no. 4 (2001): 741-748. https://doi.org/10.3892/ijo.19.4.741