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

Autor: Doller A; Pharmazentrum Frankfurt/ZAFES, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Badawi A; Pharmazentrum Frankfurt/ZAFES, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Schmid T; Institut für Biochemie I (Pathobiochemie), Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Brauss T; Institut für Biochemie I (Pathobiochemie), Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Pleli T; Medizinische Klinik 1, Schwerpunkt Gastroenterologie und Hepatologie, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., zu Heringdorf DM; Pharmazentrum Frankfurt/ZAFES, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Piiper A; Medizinische Klinik 1, Schwerpunkt Gastroenterologie und Hepatologie, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Pfeilschifter J; Pharmazentrum Frankfurt/ZAFES, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany., Eberhardt W; Pharmazentrum Frankfurt/ZAFES, Klinikum der Goethe-Universität Frankfurt, Frankfurt/Main, Germany. Electronic address: w.eberhardt@em.uni-frankfurt.de.
Jazyk: angličtina
Zdroj: Experimental cell research [Exp Cell Res] 2015 Jan 01; Vol. 330 (1), pp. 66-80. Date of Electronic Publication: 2014 Sep 21.
DOI: 10.1016/j.yexcr.2014.09.010
Abstrakt: 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 D1 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 E2 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.
(Copyright © 2014 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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