Differential expression of Galectin-3 in pituitary tumors

Dominik Riss, Long Jin, Xiang Qian, Jill Bayliss, Bernd W. Scheithauer, William F. Young, Sergio Vidal, Kalman Kovacs, Avraham Raz, Ricardo V. Lloyd

Research output: Contribution to journalArticle

100 Scopus citations

Abstract

Galectin-3 (Gal-3), a β-galactoside-binding protein, has been implicated in a variety of biological functions, including cell proliferation and differentiation, tumor cell adhesion, angiogenesis, apoptosis, tumor progression, and metastasis. We investigated the role of Gal-3 in the development and progression of pituitary tumors. Immunohistochemical and Western blot analysis of normal and neoplastic human pituitaries showed that only lactotroph (PRL) and corticotroph (ACTH) hormone-producing cells and tumors expressed Gal-3. Gal-3 was present in 24 of 38 (63.2%) PRL adenomas, 5 of 6 (83.3%) PRL carcinomas, 19 of 41 (46.3) ACTH adenomas, and 7 of 8 (87.5%) ACTH carcinomas, but not in 112 other pituitary adenomas and carcinomas. Pituitary folliculo-stellate cells, which have macrophage-type functions in the anterior pituitary, also expressed Gal-3. Hyperplastic and neoplastic pituitaries from p27Kip1 (p27)-null mice, which produce mainly ACTH, showed increased Gal-3 expression levels compared with control mice. Treatment with transforming growth factor β1, which regulates pituitary cell proliferation, reduced Gal-3 as well as p27 expression levels in cultured HP75 pituitary cells and Gal-3 in cultured pituitary cells from p27-null mice, suggesting that p27 is not necessary for the inhibitory effects of transforming growth factor β1 on the cell cycle in the pituitary. The role of Gal-3 in pituitary cell function was examined by RNA interference experiments. Inhibition of Gal-3 gene expression by RNA interference decreased HP75 cell proliferation and increased apoptosis. These results indicate that Gal-3 has an important role in pituitary cell proliferation and tumor progression.

Original languageEnglish (US)
Pages (from-to)2251-2255
Number of pages5
JournalCancer research
Volume63
Issue number9
StatePublished - May 1 2003

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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