Expression of tumour necrosis factor-alpha (TNF-α) mRNA and protein in pathological thyroid tissue and carcinoma cell lines

Abstract

There has been much controversy about the presence of TNF‐α within thyroid tissue. We therefore conducted a study to determine if TNF‐α mRNA is present in thyroid tissue and thyroid‐derived cells. Semiquantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) was employed with a heterologous competitor fragment. Significantly lower levels of TNF‐α mRNA were found in the autonomous nodules from patients with thyroid autonomy (TA; n = 4; 5.7 ± 1.3 arbitrary units (AU) (mean ± s.e.m.); P < 0.03) and in normal thyroid tissue (n = 2, 7.0 ± 3.1 AU) compared with tissue from patients with Graves’ disease (GD; n = 13; 27.9 ± 10.3 AU), non‐toxic multinodular goitre (NTG; n = 5; 20.9 ± 5.8 AU) and perinodular tissue from TA patients (20.3 ± 4.0 AU). Higher levels were detected in tissues from patients with Hashimoto’s thyroiditis (HT; n = 2; 51.3 ± 10.3 AU). Cultures of pure thyroid‐derived fibroblasts (46 ± 18 AU), thyrocytes (33 ± 8 AU), and the anaplastic thyroid carcinoma cell lines 8505 C (39 ± 11 AU), SW 1736 (214 ± 16 AU) and C 643 (3 ± 1 AU) showed significantly lower TNF‐α mRNA levels than thyroid‐derived lymphocytes (1650 ± 32 AU). TNF‐α was detected in the supernatants of unstimulated lymphocytes (22.1 ± 1.1 pg/ml) and SW 1736 cells (3.5 ± 0.9 pg/ml), but not in unstimulated fibroblasts and thyrocytes. Using an intracellular labelling technique in flow cytometry, the immunophenotype of stimulated TNF‐α‐positive lymphocytes was determined as predominantly CD3+CD45RO+. Our results suggest that TNF‐α is present in the thyroid tissue of different thyroid disorders. Thyroid‐derived lymphocytes are potential TNF‐α producers and may thus locally influence thyroid function.

Autoinduction of tumor necrosis factor-α in FRTL-5 rat thyroid cells

“…This cytokine is detectable in thyroid tissues obtained from patients with Hashimoto's thyroiditis (Ajjan et al 1996, Aust et al 1996. In accordance, we and others have demonstrated enhanced TNF gene expression in the inflamed thyroid of BioBreeding/Worcester (BB/W) rats (Mori et al 1998, Bluher et al 1999.…”

“…While the majority of TNF detected in inflamed thyroid tissues is produced by infiltrating inflammatory cells (Aust et al 1996), studies demonstrate the production of TNF by thyroid epithelial cells (Zheng et al 1992, Mori et al 1998. It may be possible that TNF produced by infiltrating inflammatory cells induces its own expression in thyrocytes in the area of infiltration, since autoinduction of TNF has been demonstrated in HL-60 human promyelocytic leukemia cells and in rat tracheal epithelial cells (Spriggs et al 1990, Bader & Nettesheim 1996.…”

Inflammatory mediators, tumor necrosis factor-α and interferon-γ, induce EMT in human PTC cell lines

“…The oncogenes activated in thyroid carcinomas, including RET/PTC, RAS and BRAF, which trigger the MAPK cascade, can induce a cell-autonomous proinflammatory transcriptional program in thyrocytes, which includes expression of cytokines, chemokines and their receptors (7). Proinflammatory cytokines, such as tumor necrosis factor (TNF)-α and interferon (IFN)-γ, are important inflammatory mediators of these processes (8,9). TNF-α and IFN-γ are pleiotropic cytokines expressed in various types of tumor cells and cells in the tumor microenvironment, exerting a variety of pro-tumoral activities in solid tumors (10,11).…”

Tyrosine kinase oncoprotein, RET/PTC3, induces the secretion of myeloid growth and chemotactic factors

“…Specifically, tumor tissue or tumor-derived cell lines from differentiated carcinomas secrete G-CSF, GM-CSF, IL-1a, IL-6, IL-8, MCP-1 and/or TNF-a (Tohyama et al, 1992;Kayser et al, 1995Kayser et al, , 1996Nakada et al, 1996;Basolo et al, 1998;Kurebayashi et al, 2000;Scarpino et al, 2000), whereas undifferentiated thyroid carcinomas have been shown to produce the cytokines GROa, G-CSF, GM-CSF and IL-1a, IL-6, IL-8 and/or TNF-a (Enomoto et al, 1990;Yoshida et al, 1992Yoshida et al, , 1994Aust et al, 1996Aust et al, , 2001Basolo et al, 1998;Asakawa and Kobayashi, 1999). Moreover, the cell lines known to express an activated form of c-RET express the cytokines IL-6 and IL-8, suggesting that c-RET activation may directly signal cytokine expression (Basolo et al, 2002;Iwahashi et al, 2002).…”