Involvement of wild-type p53 in radiation-induced c-Jun N-terminal kinase activation in human thyroid cells.

c-jun-N-terminal kinases (JNKs) play an important role in defense against external stresses including ionizing radiation (IR). We have previously shown that sensitivity to IR is influenced by p53 status in human thyroid cells. In this study, we investigated the effect of p53 status on IR-induced JNK activation in human thyroid cells. Our results showed high basal JNK activity in the p53-null thyroid cancer cell line, FRO. In contrast, primary cultured thyroid cells (PT), which harbor wild-type p53, had low basal JNK activity. IR increased JNK activity in PT, however, no such increase was noted in FRO cells. Introduction of the wild-type p53 into FRO cells reduced JNK activity to a low basal level and rendered it responsive to IR. There was no difference in IR-induced ceramide production between PT and FRO cells. Our results provide clear evidence that p53 status influences, directly or indirectly, radiation-induced JNK activation in human thyroid cells, suggesting that a feedback or interaction pathway between p53 and JNK regulates radiation-induced cell fate.

Prostaglandin E2 up-regulates macrophage-derived chemokine production but suppresses IFN-inducible protein-10 production by APC.

PGE(2) has been known to suppress Th1 responses. We studied the role of PGE(2) in two representative chemokines, macrophage-derived chemokine (MDC) and IFN-inducible protein-10, production by LPS- or CD40-stimulated spleen cells. The production of MDC, one of the ligands for CCR4 preferentially expressed on Th2, was enhanced in nonstimulated, LPS-, CD40-, or CD3-stimulated spleen cells by the pretreatment with PGE(2), while the production of IFN-inducible protein-10, a representative ligand for CXC chemokine receptor 3 expressed on Th1, was suppressed. MDC production was also enhanced by IL-4, IL-5, and intracellular cAMP-elevating agents such as dibutyryl cAMP and 3-isobutyl-1-methylxanthine, and the effect of IL-4, IL-5, and PGE(2) was additive. However, the pretreatment with IL-6, IL-10, or TGF-beta, or the neutralization of IFN-gamma or IL-12 had no effect on MDC production. B cells, macrophages, and dendritic cells were main producers of MDC, while T cells produced only a small amount of MDC. MDC production by B cells was equally stimulated by LPS and anti-CD40 Ab, while that by macrophages and dendritic cells was more markedly stimulated by anti-CD40 Ab, and PGE(2) further enhanced MDC production by these stimulated cells. These results indicate that PGE(2) regulates Th1/Th2-related chemokine production by B cells, macrophages, and dendritic cells, and that this is a new function of PGE(2) for the regulation of Th2 immune responses at the induction and activation stages.

Macrophage-colony stimulating factor inhibits the growth of human ovarian cancer cells in vitro.

The effect of macrophage-colony stimulating factor (M-CSF), which regulates the growth and differentiation of haematopoietic progenitor cells on the growth of ovarian cancer cells was investigated in three ovarian cancer cell lines in vitro. The spontaneous growth of these cells was significantly inhibited by the addition of M-CSF in a concentration-dependent manner over 96 h of culturing. The maximum response was obtained with 10 ng/ml (3857 U/ml) of M-CSF by counting the viable cell number using the trypan blue exclusion assay. [(3)H]-thymidine incorporation by these cells was also suppressed following a 96-h incubation with M-CSF. The inhibitory effect of M-CSF was reversed by the addition of anti-M-CSF monoclonal antibody. Flow cytometric analysis revealed that the treated ovarian cancer cells arrested at the G0/G1 phase of the cell cycle. These cells expressed M-CSF receptors on their surface as detected by Scatchard plot analysis using (125)I-labelled M-CSF. These results indicate that M-CSF has an antitumour activity for ovarian cancer cells and suggest that it can be applied for the treatment of this disease.

Inhibition of angiogenesis and tumorigenesis, and induction of dormancy by p53 in a p53-null thyroid carcinoma cell line in vivo.

Our recent in vitro findings for suppression of thrombospondin-1 (TSP1; an antiangiogenic factor) expression by wild-type (wt) p53 in a p53-null thyroid carcinoma cell line, FRO, prompted us to investigate the in vivo effect of exogenous wt-p53 and TSP1 expression on tumor growth and angiogenesis of FRO xenografts in nude mice. Overexpression of TSP1, which did not affect the in vitro cell growth, significantly inhibited the in vivo tumor growth and neovascularization but not tumorigenesis; all the mice inoculated with FRO cells expressing TSP1 developed tumors, which were smaller and less vascularized than those derived from FRO cells. In contrast, restoration of wt-p53 expression, which reduced the in vitro cell growth rate, inhibited tumorigenesis and induced a state of "dormancy". Thus, approximately 40% of mice inoculated with FRO cells expressing wt-p53 (FRO-p53) were tumor free and the remaining mice developed hypovascular tumors which remained small (< or = 5 mm in size) for up to 60 days. Of interest, the phenotype of FRO-p53 tumors reverted to a well vascularized, progressively expanding tumor by exogenous expression of vascular endothelial growth factor (a proangiogenic factor). Our data demonstrated wt-p53 inhibition of tumorigenesis and induction of dormancy by suppression of neovascularization in FRO cells. The results suggest that p53 gene therapy for thyroid carcinoma harboring p53 mutation may be more efficacious than we had expected from previous in vitro data.

Chinese medicinal herb, Acanthopanax gracilistylus, extract induces cell cycle arrest of human tumor cells in vitro.

We investigated the effect of a Chinese medicinal herb, Acanthopanax gracilistylus (AG), extract (E) on the growth of human tumor cell lines in vitro. AGE markedly inhibited the proliferation of several tumor cell lines such as MT-2, Raji, HL-60, TMK-1 and HSC-2. The activity was associated with a protein of 60 kDa, which was purified by gel-filtration chromatography. Cell viability analyses indicated that the treatment with AGE inhibits cell proliferation, but does not induce cell death. The mechanism of AGE-induced inhibition of tumor cell growth involves arrest of the cell cycle at the G(0) / G(1) stage without a direct cytotoxic effect. The cell cycle arrest induced by AGE was accompanied by a decrease of phosphorylated retinoblastoma (Rb) protein. Furthermore, cyclin-dependent kinases 2 and 4 (Cdk2 and Cdk4), which are involved in the phosphorylation of Rb, were also decreased. These results suggest that AGE inhibits tumor cell growth by affecting phosphorylated Rb proteins and Cdks.

Sensitivity difference to the suppressive effect of prostaglandin E2 among mouse strains: a possible mechanism to polarize Th2 type response in BALB/c mice.

PGE2 has been shown to play a prominent role in regulating Th1 and Th2 type responses. We studied the role of PGE2 in IFN-gamma production by Staphylococcus aureus Cowan I-stimulated spleen cells from several mouse strains such as BALB/c, C3H/HeN, and C57BL/6. When spleen cells were pretreated with indomethacin (cyclooxygenase (COX)-1 and COX-2 inhibitor) or NS-398 (COX-2-specific inhibitor), S. aureus Cowan I -induced IFN-gamma production was increased more markedly in spleen cells from BALB/c mice than from C3H/HeN and C57BL/6 mouse. However, PGE2 production was not significantly different among spleen cells from three mouse strains. When various concentrations of PGE2 were exogeneously added to spleen cells, PGE2 showed a stronger suppressive effect on IFN-gamma production in spleen cells from BALB/c mice than from other strains of mice. This suppressive effect of PGE2 in BALB/c mice mainly depended on IL-12p70 production by APCs. More PGE2 binding sites were found in BALB/c spleen cells than in C3H/HeN spleen cells, indicating that the sensitivity difference to the suppressive effect of PGE2 was due to the difference of the number of PGE2 receptors. The administration of NS-398 into BALB/c mice enhanced Ag-specific IFN-gamma production, but not IL-4 production. This effect is the same as IL-12 administration in vivo. From these results, we propose that the modulation of PGE2 is important for Th1 activation via IFN-gamma and IL-12p70 production in vitro and in vivo and that PGE2 is one of the pivotal factors in the Th2-dominant immune response in BALB/c mice.

Thyrocyte proliferation by cellular adhesion to infiltrating lymphocytes through the intercellular adhesion molecule-1/lymphocyte function-associated antigen-1 pathway in Graves' disease.

Graves' disease (GD) is an autoimmune thyroid disease characterized by infiltration of lymphocytes into the thyroid, and intrathyroid lymphocytes are known to play an important role in the pathogenesis of GD. However, it remains to be understood how lymphocytes adhere to thyrocytes and regulate the thyrocyte function through cellular adhesion. We studied the mechanisms of T cell adhesion to thyrocytes using intrathyroid mononuclear cells (ITMC) and thyrocytes purified from the thyroids of patients with GD. The following novel features of cellular adhesion of ITMC to thyrocytes in the regulation of the thyrocyte function in GD were observed: 1) GD-ITMC expressed lymphocyte function-associated antigen (LFA)-1, which became an active adhesive configuration much higher than peripheral blood mononuclear cells (PBMC) from normal volunteers and GD patients; 2) GD-thyrocytes expressed a high quantity of intercellular adhesion molecule (ICAM)-1; 3) GD-ITMC adhered to GD-thyrocytes, whereas normal PBMC required activation stimuli by phorbol myriacetate, a pharmacological integrin-trigger, to adhere to GD- thyrocytes; 4) monoclonal antibody-blocking studies showed that the adhesion of the activated PBMC and ITMC to thyrocytes was mainly mediated by the LFA-1/ICAM-1 pathway; 5) the adhesion of GD-thyrocytes to the activated-PBMC or ITMC induced the proliferation of the thyrocytes, which was blocked by the addition of ICAM-1 and/or LFA-1 monoclonal antibodies; and 6) in GD thyrocytes of early cultures, ICAM-1 expression on GD-thyrocytes and its adhesion to LFA-1 on phorbol myriacetate-activated PBMC or ITMC were not modulated by the addition of interleukin-1beta or interferon-gamma, and proliferation of thyrocytes by the cellular adhesion via the ICAM-1/LFA-1 pathway was independent of the proliferative response of these cytokines. Taken together, these results suggest that lymphocytes infiltrating GD thyroid induce proliferation of GD-thyrocyte by the cellular adhesion to thyrocytes via ICAM-1/LFA-1, which may lead to the development of a goiter.

[Autoantibody against Na+/I- symporter (NaIS)].

Na+/I- symporter (NaIS) cDNA was first cloned in 1996. Endo et al. reported that autoantibody against NaIS was found in 84% sera from patients with Graves' disease and 12% sera from patients with Hashimoto's thyroiditis. These IgGs, purified from sera from patients with Hashimoto's thyroiditis, caused 14 to 62% inhibition of iodide uptake. Furthermore, Ajjan et al. reported that 30.7% sera from patients with Graves' disease inhibited 7 to 44% of iodide uptake. In addition, Morris et al. suggested that NaIS represents an important autoantigen in autoimmune thyroid disease. In conclusion, it is suggested that the incidence of the antibodies against NaIS is higher in Graves' disease than Hashimoto's thyroiditis, and these antibodies inhibit iodide uptake.

Interleukin-1alpha regulates G1 cell cycle progression and arrest in thyroid carcinoma cell lines NIM1 and NPA.

This study provides the first report that the same cytokine (interleukin-1 (IL-1)) can induce opposite effects on cyclin-dependent kinases (Cdks) and Cdk inhibitors (Cdkis) in the G1 phase even in the same type of cancer cells (papillary thyroid carcinoma cells). Cell cycle analysis revealed an increase in NIM1 cells and a decrease in NPA cells in the S and G2+M phases after treatment with IL-1alpha. The addition of IL-1alpha to NIM1 cells reduced the expression of p16 and p21 protein and induced the expression of Cdk2 and Cdk4 protein, which leads to the phosphorylation of retinoblastoma protein. The addition of IL-1alpha to NPA cells induced the expression of p27 protein and reduced the expression of Cdk2 protein, which leads to induction of p107 protein expression. It is of interest that p21 protein expression was not observed in NPA cells. These results suggest that several Cdks and Cdkis play a regulatory role in the G1 cell cycle progression and arrest induced by IL-1alpha in thyroid carcinoma cell lines.

Induction of expression of MHC-class-II antigen on human thyroid carcinoma by wild-type p53.

Mutation of the tumor-suppressor gene p53 is involved in carcinogenetics. We investigated the role of p53 in the induction of anti-tumor immune responses by establishing a thyroid carcinoma cell line (1F3) prepared by transfection of wild-type human p53 gene into a p53-deficient cell line (FRO). Our results showed for the first time the involvement of p53 in the induction of anti-tumor immune responses, as demonstrated by: (i) expression of the major-histocompatibility-complex(MHC)-class-II antigen on 1F3, but not FRO; (ii) mRNA of class-II gene was expressed both in 1F3 and in FRO, but was stable at post-transcriptional level in FRO, which restrained protein synthesis; (iii) 1F3 induced MHC-class-II-specific CD4+ cytotoxic-T-cell activity through allo-antigen presentation and co-stimulation. Although our novel results are limited to the wild-type-p53-expressing clone from a p53-deficient cell line, we suggest that the absence of p53 in carcinoma cells may reduce the induction of CD4+ cytotoxic-T-cell activity against carcinoma cells by diminishing the expression of class-II antigen.

Centrally administered parathyroid hormone (PTH)-related protein(1-34) but not PTH(1-34) stimulates arginine-vasopressin secretion and its messenger ribonucleic acid expression in supraoptic nucleus of the conscious rats.

It has been suggested that PTH-related protein (PTHrP) is an endogenous modulator of cardiovascular systems. We have reported that PTHrP(1-34), but not PTH(1-34), causes the release of arginine-vasopressin (AVP) from the supraoptic nucleus (SON) of the hypothalamus in vitro through a novel receptor distinct from the PTH/PTHrP receptors (type I or type II) described previously. In this study, we have investigated the in vivo effects of PTHrP(1-34) on AVP secretion and its, messenger RNA (mRNA) expression in the SON in conscious rats. Intracerebroventricular (i.c.v.) administration of PTHrP(1-34) resulted in an increase in plasma AVP concentration in a dose-dependent manner (0-400 pmol/rat). The maximal effect was obtained at 15 min after i.c.v. administration of PTHrP(1-34). Neither PTHrP(7-34) nor PTH(1-34) had any effect on plasma AVP levels. PTHrP(1-34)-induced AVP secretion was antagonized by pretreatment with PTHrP(7-34) but not by that with PTH(1-34). In addition, in situ hybridization study revealed that AVP mRNA expression in the SON and paraventricular nucleus was significantly increased 30 min after i.c.v. administration of PTHrP(1-34) and reached a maximum at 180 min. Furthermore, in Northern blot analyses, AVP mRNA expression in the SON was increased to approximately a 2-fold of basal level by PTHrP(1-34). On the other hand, neither PTHrP(7-34) or PTH(1-34) had any effect on the mRNA expression. The PTHrP(1-34)-stimulated AVP mRNA expression was eliminated by pretreatment with PTHrP(7-34) but not with PTH(1-34). These results suggest that, in the central nervous system, PTHrP(1-34) is involved in AVP secretion through a novel receptor distinct from the PTH/PTHrP receptors reported previously, playing a role in the body water and electrolyte homeostasis.

Expression of the neoplastic phenotype by human thyroid carcinoma cell lines requires NFkappaB p65 protein expression.

We have investigated the role of the NFkappaB complex in the process of thyroid carcinogenesis by analysing thyroid carcinoma cell lines. A significant increase in p65 NFkappaB mRNA and protein expression, compared to normal thyroid cultures or tissue, was found in all of the cancer cell lines. Conversely, only a modest increase in the p50 NFkappaB mRNA and protein was found in most, but not all carcinoma cell lines. The block of p65 protein synthesis with specific antisense oligonucleotides greatly reduced the ability of two undifferentiated carcinoma cell lines to form colonies in agar and reduced their growth rate. On the other hand, no effect was observed in the same cell lines when treated with p50 specific antisense oligonucleotides. These inhibitory effects seem to be mediated by the suppression of c-myc gene expression, since treatment with antisense oligonucleotides for p65 gene interfered negatively with c-myc gene expression. Our results indicate that activation of the NFkappaB complex by overexpression of p65 plays a critical role in the process of thyroid cell transformation.

Parathyroid hormone-related peptide-(1-34) [PTHrP-(1-34)] induces vasopressin release from the rat supraoptic nucleus in vitro through a novel receptor distinct from a type I or type II PTH/PTHrP receptor.

PTH and PTH-related peptide (PTHrP) bind to a type I PTH/PTHrP receptor expressed in bone and kidney or a type II receptor in nonclassical target tissue with equal affinity and similar bioactivities. PTHrP is abundant in the central nervous system, but its physiological role remains unknown. Herein, we examined the role of PTHrP-(1-34) on arginine vasopressin (AVP) release from the rat supraoptic nucleus (SON). Application of PTHrP-(1-34) to SON slices caused an increase in AVP release in a concentration-dependent manner. Neither PTHrP-(7-34) nor PTH-(1-34) had any effect on AVP release from the SON. PTHrP-(1-34)-induced AVP release was antagonized by a large excess of PTHrP-(7-34) and by H89, an inhibitor of cAMP-dependent protein kinase (A kinase), but not by PTH-(1-34) or PTH-(13-34). PTHrP-(1-34), but not PTH-(1-34), also dose-dependently increased the levels of cAMP in the SON. 125I-Labeled PTHrP-(1-34) bound specifically to crude membranes isolated from the SON. Scatchard analysis showed a single class of binding sites for PTHrP-(1-34) with a Kd of 36.4 nM and a maximum binding capacity of 3.94 pmol/mg protein. No specific binding for 125I-labeled PTH-(1-34) was noted. The binding of 125I-labeled PTHrP-(1-34) was displaced by unlabeled PTHrP-(1-34) and unlabeled PTHrP-(7-34), but not by unlabeled PTH-(1-34). These findings suggest that PTHrP-(1-34), but not PTH-(1-34), causes the release of AVP from the SON through a novel receptor distinct from type I or II PTH/PTHrP receptors.

Reexpression of thyroid peroxidase in a derivative of an undifferentiated thyroid carcinoma cell line by introduction of wild-type p53.

Loss of function of p53 is believed to result in transformation through impairment of its properties as a transcription factor, which interferes with the regulation of the cell cycle and under certain conditions, with programmed cell death. We report that stable transfection of clonal undifferentiated thyroid carcinoma cell lines harboring endogenous p53 mutations with a wild-type p53 expression vector only rarely yields transfectants expressing authentic wild-type p53. Among these, most exhibited an increase in doubling time and an impairment of colony formation in soft agar. Only one clonal wild-type p53-overexpressing derivative of the NPA papillary carcinoma cell line was obtained, and these cells were found to reexpress thyroid peroxidase (TPO). This clone also demonstrated reexpression of the paired box domain transcription factor Pax-8, which specifically activates transcription of TPO. Wild-type p53 did not directly stimulate transcriptional activity of a TPO promoter construct. Although the low frequency of authentic wild-type p53 stable transfectants limits the power of this analysis, these data suggest that in addition to its role in malignant transformation, p53 may be significant in the determination or maintenance of cell differentiation in thyroid neoplasms.

Stimulatory effect of interleukin-1 alpha on proliferation through a Ca2+/calmodulin-dependent pathway of a human thyroid carcinoma cell line, NIM 1.

NIM 1 cells, a human thyroid cell line established from a patient with thyroid papillary adenocarcinoma, produce cytokines such as interleukin-1 alpha (IL-1 alpha) and granulocyte-colony stimulating factor. In the present study, we investigated the signal transduction pathway in the proliferation of NIM 1 cells evoked by IL-1 alpha. Incubation of NIM 1 cells with IL-1 alpha for 48 h increased the incorporation of 3H-thymidine (3H-TdR). The stimulatory effect of IL-1 alpha was evident at 0.01 ng/ml and the maximal effect was seen at 10 ng/ml. IL-1 alpha evoked an influx of 45Ca into NIM 1 cells within 3 min in a concentration-dependent manner (0.01-1 ng/ml). These stimulatory effects of IL-1 alpha on both 3H-TdR incorporation and 45Ca influx were similarly inhibited by nicardipine, an inhibitor of voltage-dependent Ca2+ channels, in a concentration-dependent manner (10-1000 nM). The stimulatory effect of IL-1 alpha on 3H-TdR incorporation was inhibited by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), an antagonist of calmodulin, but not by 1-(5-isoquinoline sulfonyl)-2-methylpiperazine (H-7), an inhibitor of protein kinase C. While the culture medium initially contained 0.75 mM Ca2+, inhibition of 3H-TdR incorporation by nicardipine and W-7 under these baseline conditions was also recognized. These results suggest that IL-1 alpha stimulates cell proliferation through a Ca2+/calmodulin-dependent pathway in NIM 1 cells.

Germ line mutation in the RET proto-oncogene associated with familial multiple endocrine neoplasia type 2B: a case report.

Multiple endocrine neoplasia type 2 (MEN 2) is a dominantly inherited cancer syndrome. MEN 2B is characterized by the combined occurrence of medullary thyroid carcinoma (MTC), pheochromocytoma, mucosal neuroma and Marfanoid habitus. Recently, a missense mutation in codon 918 of the proto-RET has been reported in the germ line of apparently distinct families with MEN 2B. In the present paper we first show a familial case of MEN 2B in Japan also to be associated with a germ line mutation in codon 918 of the proto-RET. The mutation was the substitution of a threonine for a methionine in the tyrosine kinase domain of the protein. The germ-like mutations of the proto-RET in MEN 2A and MEN 2B are the first examples of a dominantly acting oncogenic point mutation initiating human hereditary neoplasia.

Mutations of the adenomatous polyposis coli gene in sporadic thyroid neoplasms.

Several epidemiological studies have demonstrated an association between familial adenomatous polyposis coli (FAP) and thyroid neoplasms. Predisposition to FAP is conferred by mutations in the APC gene, located on chromosome 5q21. Somatic mutations of APC are also observed in about 60% of sporadic colorectal adenomas and carcinomas, suggesting that disruption of this putative tumor suppressor gene may play a role in both familial as well as acquired colorectal tumorigenesis. The APC gene is expressed in normal human thyroid, thyroid adenomas, and differentiated carcinoma tissues as well as in four clonal human thyroid carcinoma cell lines, as demonstrated by reverse transcriptase-polymerase chain reaction of a 388-base APC messenger ribonucleic acid fragment spanning exons 14 and 15, followed by hybridization to an exon 15-specific complementary DNA probe. Eighty human thyroid neoplasms were examined for loss of heterozygosity of the APC locus, using primers flanking a hypervariable dinucleotide (CA) repeat (CB26) immediately adjacent to the APC gene. Of 71% informative samples, 2 showed allelic loss: a follicular adenoma (FA) and a nodule from a multinodular goiter (MNG). The DNA of 83 benign and malignant thyroid neoplasms and 4 thyroid carcinoma cell lines was examined for mutations within a 1200-basepair stretch of exon 15 by single strand conformation polymorphism. Five sets of overlapping primers were used for PCR. The anaplastic thyroid carcinoma cell line (ARO) had 1 APC allele with an adenine insertion at codon 1556 (ACTA to AACTA), leading to a premature stop codon at 1558. An anaplastic carcinoma had a mutation of codon 1346 (TCA-CCA; Ser to Pro). In summary, the APC gene is expressed in normal and neoplastic human thyroid tissue and is a target for inactivating mutations in some thyroid tumors.

Aberrant deoxyribonucleic acid methylation in human thyroid tumors.

DNA methylation is a covalent modification of cytosine residues that occurs at the dinucleotide sequence CpG in vertebrates. Abnormal patterns of DNA methylation are observed consistently in human tumors, including widespread areas of genomic hypomethylation as well as regional sites of hypermethylation. We examined the DNA of benign and malignant human thyroid tumors for changes in the methylation state of the genes for human GH, platelet-derived growth factor B-chain, and H-ras. The human GH gene was aberrantly methylated in 6 of 22 (27%) nodules from multinodular goiters (MNG), 21 of 33 (64%) follicular adenomas (FA), and 10 of 16 (63%) papillary carcinomas (PC). Platelet-derived growth factor B-chain was also abnormally methylated in 4 of 13 (31%) MNG, 17 of 24 (71%) FA, and 9 of 13 (69%) PC. The H-ras gene, located within a region on chromosome 11p known to be a hot spot for hypermethylation in other tumors types, showed complex patterns of methylation (mainly hypermethylation) in 6 of 22 (27%) MNG, 22 of 35 (63%) FA, and 10 of 16 (63%) PC. Those tumors with methylation abnormalities tended to be affected at multiple loci (i.e. aberrant patterns with all 3 probes), whereas those that were negative were usually normal at all sites. Benign and malignant thyroid neoplasms show a high prevalence of aberrant methylation patterns of selected genes. Adenomatous nodules from multinodular goiters, consisting largely of hyperplastic tissue, have a lower frequency of these events. Aberrant DNA methylation may contribute to subsequent cell transformation through changes in DNA conformation, transcriptional activity, and/or increased fragile site instability. This suggests that widespread changes in DNA methylation may occur as a relatively early step in thyroid tumor formation.

Autocrine stimulation of interleukin-1 in the growth of human thyroid carcinoma cell line NIM 1.

We reported first in this study that human thyroid cell line NIM 1 established from a patient with papillary adenocarcinoma of the thyroid associated with hypercalcemia and peripheral neutrocytosis produced interleukin (IL)-1 alpha and IL-1 beta in the culture supernatant and cell lysate as detected by murine thymocyte proliferative response and enzyme-linked immunosorbent assay. Production of IL-1 alpha and IL-1 beta was further confirmed by the demonstration of IL-1 alpha and IL-1 beta messenger ribonucleic acid expression with Northern blot hybridization analysis. The in vitro growth of NIM 1 cells was inhibited by the addition of anti-IL-1 alpha and IL-1 beta antibody. The growth of NIM 1 cells was further enhanced by the addition of recombinant human IL-1 alpha and IL-1 beta, whereas this enhancement was also inhibited by the addition of anti-IL-1 antibody. IL-1 receptors were expressed on NIM 1 cells. These results suggest that IL-1 plays a regulatory role in the growth of NIM 1 cells by an autocrine mechanism.