Down-regulation of Wee1 kinase by a specific subset of microRNA in human sporadic pituitary adenomas

Henriett Butz, István Likó, Sándor Czirják, Péter Igaz, Mohammed Munayem Khan, Vladimir Zivkovic, Katalin Bálint, Márta Korbonits, Károly Rácz, Attila Patócs

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Abstract

Context: The tumorigenic mechanisms involved in pituitary adenomas, especially of nonfunctional pituitary adenomas (NFAs), remains unclear. Various cell cycle inhibitors have been found to be underexpressedinpituitarytumors; however, Wee1 kinase, a nuclear protein that delays mitosis and was recently recognized as a tumor suppressor gene, has not been previously investigated in pituitary tumors. Objective: Our objective was to examine the expression of Wee1 in pituitary tumors and to identify microRNAs (miRs) that can regulate its expression. Design: Expression of Wee1 was examined by immunohistochemistry and quantitative real-time PCR (qRT-PCR). Identification of miRs targeting the Wee1 3́-untranslated region was performed bymiRarray followed by expression analysis of identified miRs using qRT-PCR. Dual-luciferase assay and transient transfection of miRs into Hela cells followed by immunoblot analysis of Wee1 protein and cell proliferation analysis were carried out. Patients: A total of 57 pituitary tissue samples including 27 NFAs, 15 GH-producing adenomas with or without prolactin overproduction, and 15 normal pituitary glands were analyzed. Results: Wee1 protein expression was decreased in NFAs and GH-producing tumors with or without prolactin production, but no change in mRNA expression was observed with qRT-PCR. A specific subset of five miRNAs revealed by in silico target prediction was significantly overexpressed in NFA samples; three miRs (miR-128a, miR-155, and miR-516a-3p) targeted the 3′-untranslated region of the Wee1 transcript, and exogenous overexpression of these miRs inhibited Wee1 protein expression and HeLa cell proliferation. Conclusions: To our knowledge, this is the first report suggesting that regulation of Wee1 kinase by miRs may be linked to pituitary tumorigenesis.

Original languageEnglish
Pages (from-to)E181-E191
JournalJournal of Clinical Endocrinology and Metabolism
Volume95
Issue number10
DOIs
Publication statusPublished - Oct 2010

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ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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