Expression of P-glycoprotein in HeLa cells confers resistance to ceramide cytotoxicity

  • Authors:
    • Jacqueline V. Chapman
    • Valérie Gouazé-Andersson
    • Myles C. Cabot
  • View Affiliations

  • Published online on: December 1, 2010     https://doi.org/10.3892/ijo_00000813
  • Pages: 1591-1597
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Abstract

The role of glucosylceramide synthase (GCS) in regulating ceramide-induced apoptosis has been widely studied. The purpose of this investigation was to evaluate the role of P-glycoprotein (P-gp) in regulating ceramide cytotoxicity by using C6-ceramide. To accomplish this, we employed HeLa cells with conditional expression of the multidrug resistance gene 1/P-gp. HeLa cells expressing P-gp (P-gp/on cells) challenged with [14C]C6-ceramide (6 µM), synthesized 4.5-fold the amount of C6-glucosylceramide (GC) compared to HeLa cells with suppressed expression of P-gp (P-gp/off cells), whereas the generated levels of C6-sphingomyelin were almost equal (33 and 29% of intracellular 14C, respectively). Tamoxifen, a P-gp antagonist, decreased the C6-GC levels from 3.5-1.0% in the P-gp/off and from 17-2.8% of the total lipid 14C levels in the P-gp/on cells. Tamoxifen did not inhibit cell-free C6-GC synthesis in the P-gp/off or P-gp/on homogenates. However, a specific GCS inhibitor, ethylenedioxy-1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol (ethylenedioxy-P4), blocked synthesis by 90%. In the cytotoxicity assays, the P-gp/off cells were sensitive to C6-ceramide and the P-gp/on cells were resistant. Resistance to C6-ceramide in the P-gp/on cells was reversed by tamoxifen but not by ethylenedioxy-P4. Experiments in another cervical cancer model showed that multidrug-resistant P-gp-rich KB-V1 cells synthesized 3-fold more C6-GC from C6-ceramide than the parental, P-gp-poor KB-3-1 cells, and whereas tamoxifen had no effect on the C6-GC synthesis in the KB-3-1 cells, it inhibited synthesis by 70% in the KB-V1 cells. This study demonstrates that P-gp potentiates C6-ceramide glycosylation and if antagonized augments C6-ceramide sensitivity, both features previously ascribed to GCS. We propose that P-gp can be an effective target for enhancing short-chain ceramide cytotoxicity in the treatment of drug-resistant cancer.

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December 2010
Volume 37 Issue 6

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

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Spandidos Publications style
Chapman JV, Gouazé-Andersson V and Cabot MC: Expression of P-glycoprotein in HeLa cells confers resistance to ceramide cytotoxicity. Int J Oncol 37: 1591-1597, 2010
APA
Chapman, J.V., Gouazé-Andersson, V., & Cabot, M.C. (2010). Expression of P-glycoprotein in HeLa cells confers resistance to ceramide cytotoxicity. International Journal of Oncology, 37, 1591-1597. https://doi.org/10.3892/ijo_00000813
MLA
Chapman, J. V., Gouazé-Andersson, V., Cabot, M. C."Expression of P-glycoprotein in HeLa cells confers resistance to ceramide cytotoxicity". International Journal of Oncology 37.6 (2010): 1591-1597.
Chicago
Chapman, J. V., Gouazé-Andersson, V., Cabot, M. C."Expression of P-glycoprotein in HeLa cells confers resistance to ceramide cytotoxicity". International Journal of Oncology 37, no. 6 (2010): 1591-1597. https://doi.org/10.3892/ijo_00000813