This Article Full Text Full Text (PDF) All Versions of this Article: 1535-7163.MCT-07-0542v1 7/1/202    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Stephens, B. Articles by Von Hoff, D. D. Search for Related Content PubMed PubMed Citation Articles by Stephens, B. Articles by Von Hoff, D. D.

Research Articles: Therapeutics, Targets, and Development

Small interfering RNA-mediated knockdown of PRL phosphatases results in altered Akt phosphorylation and reduced clonogenicity of pancreatic cancer cells

Departments of ¹ Molecular and Cellular Biology and ² Surgery, University of Arizona, Tucson, Arizona; and Divisions of ³ Clinical Translational Research, and ⁴ Integrated Cancer Genomics, Translational Genomics Research Institute, Phoenix, Arizona

Requests for reprints: Bret Stephens, Division of Clinical Translational Research, Translational Genomics Research Institute, 445 North 5th Street, Phoenix, AZ 85004. Phone: 602-343-8743. E-mail: bstephens{at}tgen.org

Abstract

The PRL phosphatases have been implicated in cancer cell growth and metastasis in a variety of tumor types. Using cDNA microarray, we previously identified and reported PRL-1 as being highly up-regulated in pancreatic cancer cell lines. In this study, we sought to further evaluate the expression of all three PRL phosphatases in pancreatic cancer cell lines and extend our findings to in situ analysis of primary pancreatic tumors taken directly from patients. Additionally, we determine if small interfering RNA-mediated knockdown of relevant PRLs confers antitumor effects in pancreatic cancer cells. Using oligonucleotide expression arrays, mRNA levels of PRL-1 and PRL-2 but not PRL-3 were identified as up-regulated in pancreatic cancer cell lines and tumor samples taken directly from patients compared with those of normal pancreas. Focusing on PRL-1 and PRL-2, high levels of both proteins were detected in a subset of pancreatic cancer cell lines and tumor samples using Western blotting and immunohistochemistry, respectively. Small interfering RNA-mediated knockdown of PRL-1 and PRL-2 in combination resulted in a moderate reduction of cellular growth and migration in MIA PaCa-2 and PANC-1 cells. More importantly, knockdown of both PRL-1 and PRL-2 significantly inhibited colony formation of these cells in soft agar as well as serum-induced Akt phosphorylation. These data support the hypothesis that PRL phosphatases regulate key pathways involved in tumorigenesis and metastasis and that knockdown of both PRL-1 and PRL-2 is required to disrupt PRL phosphatase function in pancreatic cancer cells. [Mol Cancer Ther 2008;7(1):202–10]

Grant support: This research was funded in part by the National Foundation for Cancer Research.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

³ Supplementary data for this article are available at Molecular Cancer Therapeutics Online (http://mct.aacrjournals.org/).

Received 8/ 7/07; revised 10/ 1/07; accepted 11/29/07.