Decreased expression of retinoid X receptor isoforms in human thyroid carcinomas

Yumi Takiyama, Naoyuki Miyokawa, Akira Sugawara, Shizuo Kato, Koichi Ito, Keisuke Sato, Kensuke Oikawa, Hiroya Kobayashi, Shoji Kimura, Masatoshi Tateno

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)

Abstract

Retinoid X receptors (RXRs) are ligand-inducible transcription factors that belong to the superfamily of nuclear hormone receptors. Because RXRs heterodimerize with thyroid hormone receptor, retinoic acid receptor, vitamin D3 receptor, and peroxisome proliferator-activated receptor, they play central roles in regulating a number of signaling pathways. To understand the roles of RXRs in human thyroid carcinogenesis, we have investigated the immunohistochemical expression of RXRs in normal and neoplastic thyroid tissues. Whereas nontumorous human thyroid cells exhibited distinct nuclear staining for the RXRs, thyroid carcinomas showed decreased nuclear expression of all three RXR isoforms. In particular, some thyroid carcinoma cells showed intense RXR-α cytoplasmic staining accompanied by decreased immunoreactivity in their nuclei. This subcellular localization of RXR-α was confirmed by Western blot analysis, which showed both lower nuclear expression levels of RXR-α and a cytosolic presence of RXR-related protein in neoplastic regions. We present here, for the first time, the histological distribution of each RXR protein (α, β, and γ) in human thyroid follicular cells. In addition, we found that the nuclear expression of RXRs was lower in thyroid carcinomas than in normal tissue. The differential expressions of these RXRs in thyroid carcinomas might be implicated in the pathogenesis of thyroid cancers.

Original languageEnglish
Pages (from-to)5851-5861
Number of pages11
JournalJournal of Clinical Endocrinology and Metabolism
Volume89
Issue number11
DOIs
Publication statusPublished - 2004 Nov

ASJC Scopus subject areas

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

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