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The RNA-binding protein Sam68 contributes to proliferation and survival of human prostate cancer cells

Oncogene volume 26, pages 4372–4382 (2007)Cite this article

Abstract

The tyrosine kinase Src is frequently activated in advanced human prostate carcinomas and its activation correlates with tyrosine phosphorylation of the RNA-binding protein Sam68. Herein, we have investigated the expression and function of Sam68 in human prostate cancer cells. Analysis of specimens obtained from 20 patients revealed that Sam68 is upregulated at the protein level in 35% of the samples. Real-time polymerase chain reaction confirmed the results at the mRNA level in most patients. Downregulation of Sam68 by RNAi in LNCaP prostate cancer cells delayed cell cycle progression and reduced the proliferation rate. Moreover, depletion of Sam68 sensitized cells to apoptosis induced by DNA-damaging agents. Similarly, stable cell lines expressing a truncated GFP-Sam68GSG protein displayed reduced growth rates and higher sensitivity to cisplatin-induced apoptosis. Microarray analyses revealed that a subset of genes involved in proliferation and apoptosis were altered when Sam68 was knocked down in LNCaP cells. Our results indicate that Sam68 expression supports prostate cancer cells proliferation and survival to cytotoxic agents.

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Abbreviations

PCa:

prostate carcinoma

STAR:

signal transduction and activation of RNA metabolism

cdk:

cyclin dependent kinase

EDTA:

ethilenediaminetetraacetic acid

DMSO:

dimethyl-sulfoxide

BSA:

bovine serum albumin

SDS:

sodium dodecyl sulfate

BrdU:

5-bromo-2-deoxyuridine

MTS:

[3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt]

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Acknowledgements

We wish to thank Professor S Di Stasi for help with patients recruitment, Professor R Geremia for helpful discussion; Dr Andrea Bianchini for microarray data analysis; Drs Ezio Giorda and Rita Carsetti for help with FACS analysis. This work was supported by grants from the Associazione Italiana Ricerca sul Cancro (AIRC) and the Italian Ministry of Education (PRIN 2004) to CS MP Paronetto is supported by a Post-doctoral scholarship from the IRCCS Fondazione Santa Lucia.

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Authors and Affiliations

  1. Department of Public Health and Cell Biology, University of Rome Tor Vergata, Rome, Italy

    R Busà, M P Paronetto, D Farini, E Pierantozzi, F Botti & C Sette

  2. Department of Urology, University of Rome Tor Vergata, Rome, Italy

    F Attisani & G Vespasiani

  3. Institute for Neuroscience IRCSS Fondazione Santa Lucia, Rome, Italy

    R Busà, M P Paronetto, D F Angelini & C Sette

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  1. R Busà
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  2. M P Paronetto
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  3. D Farini
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  4. E Pierantozzi
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  6. D F Angelini
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  7. F Attisani
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  8. G Vespasiani
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  9. C Sette
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Correspondence to C Sette.

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Supplementary Information accompanies the paper on the Oncogene website (http://www.nature.com/onc).

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Busà, R., Paronetto, M., Farini, D. et al. The RNA-binding protein Sam68 contributes to proliferation and survival of human prostate cancer cells. Oncogene 26, 4372–4382 (2007). https://doi.org/10.1038/sj.onc.1210224

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