trichostatin-a and Carcinoma--Papillary

Nucleophosmin (NPM) is a multifunctional nucleolar protein that, depending on the context, can act as oncogene or tumour suppressor. Mutations of the NPM1 gene induce delocalization of NPM in acute myeloid leukaemia. Differently, in solid tumours, only NPM overexpression, but not delocalization, has been so far reported. Here, NPM localization in thyroid tumours was investigated. By using immunohistochemistry, we show increase of NPM cytoplasmic localization in follicular adenomas and papillary carcinomas compared to normal thyroid tissue (p = 0.0125 and <0.0001, respectively). NPM1 mutations commonly found in human leukaemia are not present in thyroid tumours. Immunofluorescence in cultured cell lines was utilized to discriminate between nucleolar and nuclear localization. We show that in thyroid cancer cell lines NPM localizes both in the nucleolus and in nucleus, while in non-tumorigenic thyroid cell lines localizes only in nucleolus. Either presence of the histone deacetylase inhibitor trichostatin A or absence of thyroid-stimulating hormone induces NPM nuclear localization in non-tumorigenic thyroid cell lines.

Topics: Adenocarcinoma, Follicular; Adenoma; Biomarkers, Tumor; Carcinoma; Carcinoma, Papillary; Cell Line, Tumor; Cell Nucleolus; Cell Nucleus; DNA Mutational Analysis; DNA, Neoplasm; Humans; Hydroxamic Acids; Nuclear Proteins; Nucleophosmin; Thyroid Neoplasms; Thyrotropin

Increases in Rap activity have been associated with tumor progression. Although activating mutations in Rap have not been described, downregulation of Rap1GAP is frequent in human tumors including thyroid carcinomas. In this study, we explored whether endogenous Rap1GAP expression could be restored to thyroid tumor cells. The effects of deacetylase inhibitors and a demethylating agent, individually and in combination, were examined in four differentiated and six anaplastic thyroid carcinoma (ATC) cell lines. Treatment with the structurally distinct histone deacetylase (HDAC) inhibitors, sodium butyrate and trichostatin A, increased Rap1GAP expression in all the differentiated thyroid carcinoma cell lines and in four of the six ATC cell lines. The demethylating agent, 5-aza-deoxycytidine, restored Rap1GAP expression in one anaplastic cell line and enhanced the effects of HDAC inhibitors in a second anaplastic cell line. Western blotting indicated that Rap2 was highly expressed in human thyroid cancer cells. Importantly, treatment with HDAC inhibitors impaired Rap2 activity in both differentiated and anaplastic tumor cell lines. The mechanism through which Rap activity is repressed appears to entail effects on the expression of multiple Rap regulators, including RapGEFs and RapGAPs. These results suggest that HDAC inhibitors may provide a tractable approach to impair Rap activity in human tumor cells.

Topics: Adenocarcinoma, Follicular; Azacitidine; Butyrates; Carcinoma; Carcinoma, Papillary; Cell Line, Tumor; Decitabine; DNA Methylation; Drug Screening Assays, Antitumor; Drug Synergism; Gene Expression Regulation, Neoplastic; GTPase-Activating Proteins; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Neoplasm Proteins; rap GTP-Binding Proteins; rap1 GTP-Binding Proteins; RNA, Small Interfering; Thyroid Neoplasms; Up-Regulation

The effectiveness rate of all-trans-retinoic acid (RA) is only about 30% in the clinical application of inducing thyroid carcinoma differentiation. In addition, there are severe toxic side effects, which limit its clinical application. Phase I-III clinical studies have been conducted on the combined application of two or more kinds of inductors in tumors. Nevertheless, the combination of RA with histone deacetylase inhibitors is rarely reported. This article studied the effects of differentiation for papillary thyroid carcinoma and follicular thyroid carcinoma cell lines induced by RA combined with trichostatin A (TSA), enhancing the effect of induction, while reducing the toxic side effects of a single drug, to provide a theoretical basis for preclinical trials.. After incubation with RA combined with TSA, K1 and FTC-133 were grouped into Group 1 (RA 10(-4) mol/L plus TSA 1.65 x 10(-7) mol/L), Group 2 (RA 1 x 10(-4) mol/L plus TSA 3.31 x 10(-7) mol/L), Group 3 (RA 10(-5) mol/L plus TSA 1.65 x 10(-7) mol/L), Group 4 (RA 1 x10(-5) mol/L plus TSA 3.31 x 10(-7) mol/L) by four varied concentrations and three time points (12 h, 24 h, and 48 h). The cell proliferation, conformation, toxic effect, and induced differentiation on K1 and FTC-133 cell lines were studied microscopically with hematoxylin-eosin (HE) to observe cell quantity and morphology, methyl-thiazolyl-tetrazolium (MTT) to calculate cell survival rates, and electrochemiluminescence analysis measuring in vitro thyroglobulin (Tg) levels.. The research showed that K1 and FTC-133 cells had cell spacing increases, with an outer edge of smooth, nuclear chromatin condensation after RA combined TSA. Survival rate were assessed by an analysis of variance (ANOVA) by concentration and time point, F values of K1 and FTC-133 were 23.52 and 170.14, and 57.09 and 224.35, respectively. There were significant differences for both cells (P < 0.01). The SNK analysis indicated that survival rates were in the order of Group 2 < Group 1 < Group 4 < Group 3. Tg was also assessed by ANOVA, F values of K1 were 69.63 and 101.07, and F values of FTC-133 were 79.77 and 81.72 (P < 0.01). Group 1 was compared with Group 3 of K1 and FTC-133 by the least significant difference (LSD) method, and there was no statistical difference between the two group (P = 0.06, 0.2, respectively; P > 0.05), yet a significant difference was seen between the other Groups.. Lower concentrations of RA combined with lower concentrations of TSA have both inhibited cell proliferation, decreased toxicity of the drugs, and increased the effect of K1 and FTC-133 cell differentiation. The mechanism of action may be that TSA has pretranscription DNA regulation and that RA has posttranscriptional signal regulation to enhance the effects of inhibited proliferation and differentiation of cells by transcription systems.

Topics: Adenocarcinoma, Follicular; Antineoplastic Agents; Apoptosis; Carcinoma; Carcinoma, Papillary; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Synergism; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Thyroglobulin; Thyroid Cancer, Papillary; Thyroid Neoplasms; Tretinoin

Thyroid transcription factor-1 (TTF-1), also known as NKX2-1, is a homeodomain containing transcriptional factor identified in thyroid, lung and central nervous system. In the thyroid, TTF-1 is essential for thyroid organogenesis and governs thyroid functions by regulating various thyroid-specific genes. We previously demonstrated that most differentiated thyroid neoplasms, including follicular adenomas/carcinomas and papillary carcinomas, express TTF-1 at both protein and mRNA levels. However, certain subtypes of thyroid cancers have shown low or negative expression of TTF-1. The aim of our study was to investigate the function of epigenetic modification in dysregulation of TTF-1 in thyroid carcinoma cells. We evaluated the expression of TTF-1 in primary thyroid tissues (normal thyroid, papillary carcinoma and undifferentiated carcinoma) and in thyroid carcinoma cell lines using immunohistochemistry and RT-PCR. Methylation-specific PCR targeting CpG islands of TTF-1 and chromatin immunoprecipitation (ChIP) for histone H3 lysine 9 (H3-lys9) were applied to clarify the correlation of the TTF-1 expression profile and epigenetic status. We also explored whether epigenetic modifiers, including 5-aza-deoxycytidine, could restore TTF-1 expression in thyroid carcinoma cells. In our current study, immunohistochemistry and RT-PCR showed positive expression of TTF-1 in normal thyroids and papillary carcinomas. Meanwhile, most of the undifferentiated carcinomas and the cell lines lost TTF-1 expression. No methylation in the CpG of TTF-1 promoter was detected in normal thyroids or papillary carcinomas. In contrast, DNA methylation was identified in 60% of the undifferentiated carcinomas (6/10) and 50% of the cell lines (4/8). ChIP assay demonstrated that acetylation of H3-lys9 was positively correlated with TTF-1 expression in thyroid carcinoma cells. Finally, DNA demethylating agents could restore TTF-1 gene expression in the thyroid carcinoma cell lines. Our data suggest that epigenetics is involved with inactivation of TTF-1 in thyroid carcinomas, and provide a possible means of using TTF-1 as a target for differentiation-inducing therapy through epigenetic modification.

Topics: Azacitidine; Base Sequence; Carcinoma, Papillary; Cell Line, Tumor; Chromatin Immunoprecipitation; CpG Islands; Decitabine; DNA Methylation; DNA Primers; Epigenesis, Genetic; Gene Expression Profiling; Gene Silencing; Histones; Humans; Hydroxamic Acids; Nuclear Proteins; RNA, Messenger; RNA, Neoplasm; Thyroid Gland; Thyroid Neoplasms; Thyroid Nuclear Factor 1; Transcription Factors

Radioactive iodine is used to identify and treat recurrent and metastatic thyroid cancer of follicular cell origin. Between 30% and 40% of thyroid cancers are either resistant or become resistant to radioactive iodine. Increased sodium-iodide symporter (NIS) and decreased Pendrin (PDS) activity may be associated with increased radioactive iodine effectiveness. In this investigation the effects of Trichostatin A (TSA), a histone deacetylating inhibitor, on human thyroid NIS and PDS gene expression was investigated.. Cell lines from papillary, Hürthle, and follicular cell carcinomas were treated with TSA for 72 hours at concentrations up to 100 ng/mL. NIS and PDS gene expression was determined using quantitative RT-polymerase chain reaction.. . NIS messenger RNA expression in cell carcinomas was increased 107- (1.8-307) and 217- (5.7-408) fold in papillary, 39- (20-63) and 58- (37-80) fold in Hürthle, and 459- (178-810) and 781- (412-1229) fold in follicular after treatment with 50 and 100 ng/mL of TSA, respectively. PDS messenger RNA expression in cell carcinomas was decreased 0.22- (0.05-0.45) and 0.27- (0.09-0.47) fold in papillary, 0.53- (0.46-0.60) and 0.54- (0.44-0.64) fold in Hürthle, and 0.32- (0.26-0.39) and 0.56- (0.47-0.64) fold in follicular, after the same treatment.. In thyroid cancer cell lines, TSA dramatically increased NIS gene expression and reduced PDS expression. The increased NIS expression and reduced PDS expression may make radioiodine therapy more effective in patients with thyroid cancer, especially when the tumors have no or low uptake of radioiodine.

Topics: Carcinoma, Papillary; Carrier Proteins; Cell Survival; Colonic Neoplasms; Enzyme Inhibitors; Gene Expression; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; In Vitro Techniques; Iodine Radioisotopes; Membrane Transport Proteins; Radiopharmaceuticals; Sulfate Transporters; Symporters; Thyroid Neoplasms; Tumor Cells, Cultured