Treatment of Jurkat acute T-lymphocytic leukemia cells by onconase (Ranpirnase) is accompanied by an altered nucleocytoplasmic distribution and reduced expression of transcription factor NF-κB

  • Authors:
    • Shwu Y. Tsai
    • Barbara Ardelt
    • Tze-Chen Hsieh
    • Zbigniew Darzynkiewicz
    • Kuslima Shogen
    • Joseph M. Wu
  • View Affiliations

  • Published online on: December 1, 2004     https://doi.org/10.3892/ijo.25.6.1745
  • Pages: 1745-1752
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

Onconase (Ranpirnase), a novel ribonuclease isolated from Rana pipiens oocytes, was reported to suppress cancer cell growth in vitro, reduce tumor size in animals, and augment cytotoxicity of several chemotherapeutic agents. Since onconase is currently in phase III clinical trials tested in treatment of mesothelioma, much emphasis has been placed on the mechanism of its anti-tumor activity. Previous studies have shown that onconase-responsive cells become arrested at the G1/S checkpoint of the cell cycle and also undergo apoptosis. A proposed mechanism for these effects is that the enzymatic activity of onconase targets cellular RNAs, in particular tRNA, with an accompanying inhibition of protein synthesis. In the present study, we have investigated the time- and dose-dependent effects of onconase on growth of Jurkat SN acute T-lymphocytic leukemia cells. Significant suppression of cell proliferation became evident after 72 and 96 h of treatment, and was most pronounced at the highest concentration (10 µg/ml; 8.3x10−7 M) of onconase. This reduction of cell proliferation, however, was not accompanied by measurable changes in distribution of cells at different phases of the cell cycle, but was paralleled by the induction of apoptosis, as assayed by flow cytometry, and with a modest decrease in the expression of a cell cycle regulatory retinoblastoma protein (Rb). Further biochemical analysis revealed that growth suppression was closely coordinated with a down-regulation in the steady state and subcellular distribution of NF-κB, a transcription factor known to be functionally associated with cell survival. The reduction in expression of NF-κB by onconase appeared to coincide or even precede growth suppression, suggesting a causal relationship. To further test the hypothesis that cellular localization and expression of NF-κB may be critical to cellular response to onconase, we also studied the growth effects of onconase in Jurkat-BαM cells, which, unlike the parent SN T cells, contain a stably transfected dominant-negative IκB gene. Growth suppression by onconase in BαM cells was more pronounced and occurred earlier compared to SN cells, although still did not affect changes in cell cycle phase distribution. Contrary to expectation, however, diminution in NF-κB expression by onconase was even more pronounced in BαM cells, suggesting that this transcription factor, while presumably prevented from dissociation from its inhibitory protein IκB in these cells, is even more efficiently targeted for degradation by onconase. These results implicate NF-κB and its turnover as important determinants in the anti-proliferative/apoptotic effects of onconase in acute T-lymphocytic leukemia cells.

Related Articles

Journal Cover

December 2004
Volume 25 Issue 6

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

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Tsai SY, Ardelt B, Hsieh T, Darzynkiewicz Z, Shogen K and Wu JM: Treatment of Jurkat acute T-lymphocytic leukemia cells by onconase (Ranpirnase) is accompanied by an altered nucleocytoplasmic distribution and reduced expression of transcription factor NF-κB. Int J Oncol 25: 1745-1752, 2004
APA
Tsai, S.Y., Ardelt, B., Hsieh, T., Darzynkiewicz, Z., Shogen, K., & Wu, J.M. (2004). Treatment of Jurkat acute T-lymphocytic leukemia cells by onconase (Ranpirnase) is accompanied by an altered nucleocytoplasmic distribution and reduced expression of transcription factor NF-κB. International Journal of Oncology, 25, 1745-1752. https://doi.org/10.3892/ijo.25.6.1745
MLA
Tsai, S. Y., Ardelt, B., Hsieh, T., Darzynkiewicz, Z., Shogen, K., Wu, J. M."Treatment of Jurkat acute T-lymphocytic leukemia cells by onconase (Ranpirnase) is accompanied by an altered nucleocytoplasmic distribution and reduced expression of transcription factor NF-κB". International Journal of Oncology 25.6 (2004): 1745-1752.
Chicago
Tsai, S. Y., Ardelt, B., Hsieh, T., Darzynkiewicz, Z., Shogen, K., Wu, J. M."Treatment of Jurkat acute T-lymphocytic leukemia cells by onconase (Ranpirnase) is accompanied by an altered nucleocytoplasmic distribution and reduced expression of transcription factor NF-κB". International Journal of Oncology 25, no. 6 (2004): 1745-1752. https://doi.org/10.3892/ijo.25.6.1745