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Title: The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking

Abstract

The impact of the RNA-binding protein HuR for the post-transcriptional deregulation of tumor-relevant genes is well established. Despite of elevations in HuR expression levels, an increase in cytoplasmic HuR abundance in many cases correlates with a high grade of malignancy. Here, we demonstrated that administration of the actin-depolymerizing macrolide latrunculin A, or blebbistatin, an inhibitor of myosin II ATPase activity, caused a dose- and time-dependent reduction in the high cytoplasmic HuR content of HepG2 and Huh7 hepatocellular carcinoma (HCC) cells. Subcellular fractionation revealed that in addition, both inhibitors strongly attenuated cytoskeletal and membrane-bound HuR abundance and conversely increased the HuR amount in nuclear cell fractions. Concomitant with changes in intracellular HuR localization, both cytoskeletal inhibitors markedly decreased the half-lives of cyclooxygenase-2 (COX-2), cyclin A and cyclin D{sub 1} encoding mRNAs resulting in a significant reduction in their expression levels in HepG2 cells. Importantly, a similar reduction in the expression of these HuR targets was achieved by a RNA interference (RNAi)-mediated knockdown of either HuR or nonmuscle myoin IIA. Using polysomal fractionation, we further demonstrate that the decrease in cytoplasmic HuR by latrunculin A or blebbistatin is accompanied by a marked change in the allocation of HuR and its mRNA cargomore » from polysomes to ribonucleoprotein (RNP) particles. Functionally, the basal migration and prostaglandin E{sub 2} synthesis are similarly impaired in inhibitor-treated and stable HuR-knockdown HepG2 cells. Our data demonstrate that interfering with the actomyosin-dependent HuR trafficking may comprise a valid therapeutic option for antagonizing pathologic posttranscriptional gene expression by HuR and furthermore emphasize the potential benefit of HuR inhibitory strategies for treatment of HCC. - Highlights: • We tested the effects of latrunculin A and blebbistatin on different HuR activities. • Both cytoskeletal inhibitors disturbed the RNP-polysome HuR allocation in HepG2 cells. • Accordingly, both inhibitors reduced the stability and levels of HuR controlled mRNAs. • Functionally, important HuR-triggered cell functions were impaired by both compounds. • Targeting of HuR trafficking implies a useful approach for novel antitumor therapy.« less

Authors:
;  [1]; ;  [2];  [3];  [1];  [3];  [1];  [1]
  1. Pharmazentrum Frankfurt/ZAFES, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main (Germany)
  2. Institut für Biochemie I (Pathobiochemie), Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main (Germany)
  3. Medizinische Klinik 1, Schwerpunkt Gastroenterologie und Hepatologie, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main (Germany)
Publication Date:
OSTI Identifier:
22416965
Resource Type:
Journal Article
Journal Name:
Experimental Cell Research
Additional Journal Information:
Journal Volume: 330; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0014-4827
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ACTIN; HEPATOMAS; MESSENGER-RNA; MYOSIN; PROSTAGLANDINS; TIME DEPENDENCE

Citation Formats

Doller, Anke, Badawi, Amel, Schmid, Tobias, Brauß, Thilo, Pleli, Thomas, Meyer zu Heringdorf, Dagmar, Piiper, Albrecht, Pfeilschifter, Josef, and Eberhardt, Wolfgang. The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking. United States: N. p., 2015. Web. doi:10.1016/J.YEXCR.2014.09.010.
Doller, Anke, Badawi, Amel, Schmid, Tobias, Brauß, Thilo, Pleli, Thomas, Meyer zu Heringdorf, Dagmar, Piiper, Albrecht, Pfeilschifter, Josef, & Eberhardt, Wolfgang. The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking. United States. https://doi.org/10.1016/J.YEXCR.2014.09.010
Doller, Anke, Badawi, Amel, Schmid, Tobias, Brauß, Thilo, Pleli, Thomas, Meyer zu Heringdorf, Dagmar, Piiper, Albrecht, Pfeilschifter, Josef, and Eberhardt, Wolfgang. 2015. "The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking". United States. https://doi.org/10.1016/J.YEXCR.2014.09.010.
@article{osti_22416965,
title = {The cytoskeletal inhibitors latrunculin A and blebbistatin exert antitumorigenic properties in human hepatocellular carcinoma cells by interfering with intracellular HuR trafficking},
author = {Doller, Anke and Badawi, Amel and Schmid, Tobias and Brauß, Thilo and Pleli, Thomas and Meyer zu Heringdorf, Dagmar and Piiper, Albrecht and Pfeilschifter, Josef and Eberhardt, Wolfgang},
abstractNote = {The impact of the RNA-binding protein HuR for the post-transcriptional deregulation of tumor-relevant genes is well established. Despite of elevations in HuR expression levels, an increase in cytoplasmic HuR abundance in many cases correlates with a high grade of malignancy. Here, we demonstrated that administration of the actin-depolymerizing macrolide latrunculin A, or blebbistatin, an inhibitor of myosin II ATPase activity, caused a dose- and time-dependent reduction in the high cytoplasmic HuR content of HepG2 and Huh7 hepatocellular carcinoma (HCC) cells. Subcellular fractionation revealed that in addition, both inhibitors strongly attenuated cytoskeletal and membrane-bound HuR abundance and conversely increased the HuR amount in nuclear cell fractions. Concomitant with changes in intracellular HuR localization, both cytoskeletal inhibitors markedly decreased the half-lives of cyclooxygenase-2 (COX-2), cyclin A and cyclin D{sub 1} encoding mRNAs resulting in a significant reduction in their expression levels in HepG2 cells. Importantly, a similar reduction in the expression of these HuR targets was achieved by a RNA interference (RNAi)-mediated knockdown of either HuR or nonmuscle myoin IIA. Using polysomal fractionation, we further demonstrate that the decrease in cytoplasmic HuR by latrunculin A or blebbistatin is accompanied by a marked change in the allocation of HuR and its mRNA cargo from polysomes to ribonucleoprotein (RNP) particles. Functionally, the basal migration and prostaglandin E{sub 2} synthesis are similarly impaired in inhibitor-treated and stable HuR-knockdown HepG2 cells. Our data demonstrate that interfering with the actomyosin-dependent HuR trafficking may comprise a valid therapeutic option for antagonizing pathologic posttranscriptional gene expression by HuR and furthermore emphasize the potential benefit of HuR inhibitory strategies for treatment of HCC. - Highlights: • We tested the effects of latrunculin A and blebbistatin on different HuR activities. • Both cytoskeletal inhibitors disturbed the RNP-polysome HuR allocation in HepG2 cells. • Accordingly, both inhibitors reduced the stability and levels of HuR controlled mRNAs. • Functionally, important HuR-triggered cell functions were impaired by both compounds. • Targeting of HuR trafficking implies a useful approach for novel antitumor therapy.},
doi = {10.1016/J.YEXCR.2014.09.010},
url = {https://www.osti.gov/biblio/22416965}, journal = {Experimental Cell Research},
issn = {0014-4827},
number = 1,
volume = 330,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2015},
month = {Thu Jan 01 00:00:00 EST 2015}
}