Undifferentiated Thyroid Cancer Cell Research Articles

Androgen receptor activation decreases proliferation in thyroid cancer cells.

The American Cancer Society predicted more than 52 000 new cases of thyroid cancer in 2020, making it the most prevalent endocrine malignancy. Due to the approximately threefold higher incidence of thyroid cancer in women, we hypothesize that androgens and/or androgen receptorsplay a protective role and that thyroid cancer in men represents anescape from androgen-mediated cell regulation. The analysis of androgen receptor (AR) expression in patient tissue samples identified a 2.7-fold reduction in AR expression (p < 0.005) in papillary thyroid cancer compared with matched, normal tissue. An in vitro cell model was developed by stably transfecting AR into 8505C undifferentiated thyroid cancer cells (resulting in clone 84E7). The addition of DHT to the clone 84E7 resulted in AR translocation into the nucleus and a 70% reduction in proliferation, with a shift in the cell cycle toward G1 arrest. RNASeq analysis revealed significant changes in mRNA levels associated with proliferation, cell cycle, and cell cycle regulation. Furthermore, androgen significantly decreased the levels of the G1-associated cell cycle progression proteins cdc25a CDK6 CDK4 and CDK2 as well as increased the levels of the cell cycle inhibitors, p27 and p21. The data strongly suggest that DHT induces a G1 arrest in androgen-responsive thyroid cancer cells. Together, these data support our hypothesis that AR/androgen may play a protective, antiproliferative role and are consistent with younger men having a lower incidence of thyroid cancer than women.

Signal transducer and activator of transcription 3 inhibition alleviates resistance to BRAF inhibition in anaplastic thyroid cancer.

Anaplastic thyroid cancer (ATC) is a rare type of thyroid cancer (TC) with no effective therapeutic strategy. Although surgery, chemotherapy and radiation are all available for ATC treatment, the median survival for ATC patients is less than 6months. In this study, we aimed to study on resistant mechanisms to B-Raf proto-oncogene serine/threonine kinase (BRAF) inhibitor and identify effective combinational therapy for ATC patients. TC cells were treated with Vemurafenib and cell apoptosis and viability were analyzed by flow cytometry and MTT assay. Monolayer and sphere cells were isolated from ATC cells to detect the mRNA level of stem cell markers and differentiation markers by RT-PCR. Phosphor-STAT3 level in sphere and monolayer cells was tested by Western blotting. The xenotransplantation animal model has established to analyze the anti-tumor effect of Vemurafenib and Stattic combinational therapy. Undifferentiated TC cells were resistant to Vemurafenib treatment. Sphere cells isolated from ATC showed no significant change in cell viability and apoptosis upon Vemurafenib treatment, and expressed a high level of stem cell marker and phosphor-STAT3. STAT3 inhibition enhanced the tumorigenic capacity and increased Vemurafenib sensitivity in ATC cell lines. Stattic significantly enhanced anti-tumor effect of Vemurafenib in mouse model. Our findings demonstrate that the combinational therapy of Vemurafenib and Stattic is an effective therapeutic treatment for ATC patients.

Targeted study of thyroid-stimulating hormone antibody coupled with PLGA-COOH nanoparticles for thyroid cancer

In this study, we aimed to evaluate the effect of all-trans-retinoic acid (PLGA-COOH nanoparticles) on the induction of dedifferentiation of thyroid cancer and the enhancement of iodine uptake. Patients (32 cases) with pathologically confirmed thyroid cancer (24 differentiated and 8 undifferentiated) received all trans-retinoic acid (1.0–1.5 mg/kg) for six weeks. Whole-body imaging was performed after 72 h. Using the American phogamma camera, the radioactivity counts of each pixel in the metastasis was measured by the semi-quantitative method of region of interest (ROI). Changes in uptake radioactivity of the metastases were compared before and after PLGA-COOH nanoparticle induction. The size of the metastasis was determined by ultrasound, X-ray, or computed tomography (CT), and the serum thyroglobulin (TG) was determined by radioimmunoassay. After radioiodine treatment, the average measurable iodine uptake of different sites of metastasis was significantly lower than that before treatment. After 32 patients were treated with PLGA-COOH nanoparticles, the uptake of a single lesion was increased in 14 cases (43.8%), no significant change was found in 7 cases (20.8%), and the uptake of one lesion was decreased in 6 cases (25%). In 827 cases, the metastasis decreased, 12 cases remained unchanged, and 7 cases increased. There was no correlation between the pathological type and the change of a lesion. After induction, serum TG decreased in 12 cases (40%), increased in 11 cases (36.7%), and remained unchanged in 7 cases (23.3%). Serum TG level was not related to a change in iodine uptake ability. In 12 cases (37.5%), two indexes were changed (e.g., increased iodine uptake, reduced ROI, or decreased serum TG). Thyroid-stimulating hormone nano interventional therapy breaks through the single and limitation of traditional treatment of thyroid diseases. PLGA-COOH nanoparticles can play an important role in the differentiation of differentiated thyroid cancer cells and the transformation of undifferentiated thyroid cancer cells. PLGA-COOH nanoparticles provide an effective method to induce the treatment of undifferentiated thyroid cancer.

Investigating the theragnostic potential of 131I-caerin peptide in thyroid cancer.

Caerin is a new peptide with tumour toxicity and its uptake by tumour cells is independent of the sodium iodide symporter (NIS). Thyroid cancer is the most common cancers of endocrine malignancy. Radioiodine (131I)-refractory thyroid cancer is the most lethal subtype of the thyroid cancers and remains a clinical challenge. In the current study, we investigated the 131I radiolabeling efficiency of Caerin and the effects of Caerin, 131I-Caerin and free 131I on differentiated and undifferentiated human thyroid cancer cell lines (B-CPAP and CAL-62) in vitro. Cell Counting Kit-8 was used to assess the cytotoxic effect of Caerin, 131I-Caerin and free 131I on B-CPAP and CAL-62 cells. Laser scanning confocal microscope was exploited to evaluate the uptake and internalization of Caerin by thyroid cancer cells. The Chloramine-T method was used to label the peptide with 131I. And the stability and water partition coefficient (Log P) of 131I-Caerin were studied. Our results demonstrated that Caerin and 131I-Caerin could be accumulated by B-CPAP and CAL-62 cells, resulting in killing of the thyroid cancer cells in vitro. The efficacy of 131I-Caerin is much higher than 131I, especially to undifferentiated CAL-62 cells. The results prove the feasibility of radioiodination of the 131I-Caerin via the Chloramine-T method. Moreover, the result indicate the hydrophobic 131I-Caerin was stable in 72 hours. Iodine-131-Caerin can inhibit the cell viability of thyroid cancer and hold certain promise as a theragnostic tool for human thyroid cancers.

L-GILZ binds and inhibits nuclear factor κB nuclear translocation in undifferentiated thyroid cancer cells

Proto-oncogene mutations and abnormal activation of mitogen-activated protein kinase (MAPK) signalling are recurrently found in thyroid cancers. Some thyroid neoplasms respond to drugs that inhibit MAPK pathway activation. Previously, we showed that pharmacological inhibition of MAPK in thyroid cancer cells inhibits cell proliferation and upregulates L-GILZ (long glucocorticoid-induced leucine zipper), a protein with anti-oncogenic and antiproliferative activity, and that L-GILZ is partially responsible for the antiproliferative activity of MAPK inhibitors. Here, we demonstrate that pharmacological inhibition of MAPK in the anaplastic thyroid cancer cell line CAL-62 upregulated L-GILZ, which bound nuclear factor κB (NF-κB) and inhibited its nuclear translocation. These data demonstrate a unique L-GILZ–mediated molecular mechanism that, by trapping NF-κB in the cytoplasm, contributes to the inhibition of proliferation induced by drugs targeting the MAPK transduction cascade. Enhanced knowledge of the mechanism of action of MAPK pathway–inhibiting drugs may improve their clinical use.

The cholesterol-derived metabolite dendrogenin A functionally reprograms breast adenocarcinoma and undifferentiated thyroid cancer cells

Dendrogenin A (DDA) is a tumor suppressor mammalian cholesterol-derived metabolite and a new class of ligand of the Liver X receptor (LXR), which displays tumor cell differentiation. In human MCF7 breast adenocarcinoma cells, DDA-induced cell differentiation was associated with an increased accumulation of neutral lipids and proteins found in milk indicating that DDA re-activates some functions of lactating cells. Active iodide transport occurs in the normal lactating mammary cells through the sodium/iodide symporter (NIS) and iodide (I) is secreted into milk to be used by the nursing newborn for thyroid hormones biosynthesis. In the present study, we assessed whether DDA may induce other characteristic of lactating cells such as NIS expression and iodine uptake in MCF7 breast cancer cells and extended this study to the papillary B-CPAP and undifferentiated anaplastic 8505c thyroid cancer cells. Moreover, we evaluated DDA impact on the expression of thyroid specific proteins involved in thyroid hormone biogenesis. We report here that DDA induces NIS expression in MCF7 cells and significantly increases the uptake of 131-I by acting through the LXR. In addition, DDA induces phenotypic, molecular and functional characteristics of redifferentiation in the two human thyroid carcinoma cell lines and the uptake of 131-I in the undifferentiated 8505c cells was associated with a strong expression of all the specific proteins involved in thyroid hormone biosynthesis, TSH receptor, thyroperoxidase and thyroglobulin. 131-I incorporation in the 8505c cells was stimulated by DDA as well as by the synthetic LXR ligand, GW3965. Together these data show that the re-differentiation of breast and thyroid cancer cells by DDA, is associated with the recovery of functional NIS expression and involves an LXR-dependent mechanism. These results open new avenues of research for the diagnosis of thyroid cancers as well as the development of new therapeutic approaches for radioiodine refractory thyroid cancers.

DDR1 regulates thyroid cancer cell differentiation via IGF-2/IR-A autocrine signaling loop.

Patients with thyroid cancers refractory to radioiodine (RAI) treatment show a limited response to various therapeutic options and a low survival rate. The recent use of multikinase inhibitors has also met limited success. An alternative approach relies on drugs that induce cell differentiation, as the ensuing increased expression of the cotransporter for sodium and iodine (NIS) may partially restore sensitivity to radioiodine. The inhibition of the ERK1/2 pathway has shown some efficacy in this context. Aggressive thyroid tumors overexpress the isoform-A of the insulin receptor (IR-A) and its ligand IGF-2; this IGF-2/IR-A loop is associated with de-differentiation and stem-like phenotype, resembling RAI-refractory tumors. Importantly, IR-A has been shown to be positively modulated by the non-integrin collagen receptor DDR1 in human breast cancer. Using undifferentiated human thyroid cancer cells, we now evaluated the effects of DDR1 on IGF-2/IR-A loop and on markers of cell differentiation and stemness. DDR1 silencing or downregulation caused significant reduction of IR-A and IGF-2 expression, and concomitant increased levels of differentiation markers (NIS, Tg, TSH, TPO). Conversely, markers of epithelial-to-mesenchymal transition (Vimentin, Snail-2, Zeb1, Zeb2 and N-Cadherin) and stemness (OCT-4, SOX-2, ABCG2 and Nanog) decreased. These effects were collagen independent. In contrast, overexpression of either DDR1 or its kinase-inactive variant K618A DDR1-induced changes suggestive of less differentiated and stem-like phenotype. Collagen stimulation was uneffective. In conclusion, in poorly differentiated thyroid cancer, DDR1 silencing or downregulation blocks the IGF-2/IR-A autocrine loop and induces cellular differentiation. These results may open novel therapeutic approaches for thyroid cancer.

Effect of Combined Epigenetic Treatments and Ectopic NIS Expression on Undifferentiated Thyroid Cancer Cells.

Poorly differentiated (PDTC) and anaplastic thyroid (ATC) cancer cells are characterized by the acquisition of epigenetic abnormalities, leading to the silencing of both the sodium iodide co-transporter and the Coxsackie adenovirus receptor. As aberrant histone acetylation and DNA methylation represent epigenetic mechanisms involved in neoplastic transformation, our study investigated the anticancer properties of epigenetic modifiers in thyroid carcinoma. The cytotoxicity and gene expression modulation of histone deacetylase and DNA methyltransferase inhibitors were evaluated in both PDTC and ATC. Epigenetic treatments were cytotoxic to tumor thyrocytes and restored sodium iodide co-transporter and Coxsackie adenovirus receptor, expression as well as radioiodine uptake, in PDTC but not in ATC. However, ectopic expression sodium iodide co-transporter re-activated radioiodine incorporation in ATC. The ability of epigenetic treatments to interfere with tumor proliferation and induce Coxsackie adenovirus receptor expression, coupled with the ability of ectopic sodium iodide co-transporter to restore radioiodine uptake, raise the possibility that these therapeutic approaches may provide clinical benefit to patients with thyroid carcinoma refractory to radioiodine treatment.

Abstract 5575: Androgen receptor stimulation with 5α-dihydrotestosterone (DHT) decreases PD-L1 expression in androgen-responsive thyroid cancer cells

Abstract Thyroid cancer is the most rapidly increasing cancer in the US with 64,300 new cases expected in 2016. However, there is a disparity in the incidence of thyroid cancer between females and males, with women (49,350 expected cases) developing thyroid cancer three times more often than men (14,950 expected cases). Immune elimination of nascent tumor cells may explain the difference in disease incidence between men and women. To address this hypothesis, the effect of androgen on the expression of immune checkpoint molecules in an androgen responsive-thyroid cancer cell line was examined. The undifferentiated thyroid cancer cell line, 8505C, does not express a functional androgen receptor (AR). 84E7 is a clone of 8505C that was transfected with an AR containing plasmid resulting in constitutively expressed AR. Transcriptome analysis via RNASeq was performed on 8505C and 84E7, with and without 5α-dihydrotestosterone (DHT) treatment. Raw sequencing reads were aligned to the UCSC hg19 human reference genome with Tophat, and Cufflinks was used to measure transcript abundances in Reads Per Kilobase of exon model per Million mapped reads (RPKM) as well as to find genes with statistically significant changes in expression. DHT treatment of 84E7 resulted in &amp;gt;2 fold expression changes in 1,552 genes. We examined the immune checkpoint ligands expressed on 84E7 such as CD80, CD86, PD-L1, PD-L2, ICOSL, B7-H3, B7-H4, HVEM, 4-1BBL, OX40L, CD70, CD40, and GAL9. PD-L1 was the sole immune checkpoint molecule that exhibited a significant expression change in DHT-treated 84E7 cells with a 1.8 log2 fold decrease (p=0, q=0), or 72% reduction in mRNA content. Additional studies confirmed the RNASeq results and provide evidence of both qualitative (immunofluorescence) and quantitative (flow cytometry and western blotting) decreases in PD-L1 expression with DHT treatment. These results are significant in that PD-L1 is produced by tumor cells as a strategy for subverting and evading the immune response, specifically T cells, allowing for continued tumor growth and metastases. In the thyroid, the presence of activated androgen receptors could lead to an environment that is more favorable for immune system activation and may help eliminate nascent thyroid cancer cells. Thus, men may experience a decreased incidence of thyroid cancer due to an enhanced and less inhibited anti-tumor environment. Citation Format: Timmy J. O'Connell, Melanie Jones, Anvita Gupta, Tali Lando, Deya Jourdy, Edward Shin, Augustine Moscatello, Raj Tiwari, Jan Geliebter. Androgen receptor stimulation with 5α-dihydrotestosterone (DHT) decreases PD-L1 expression in androgen-responsive thyroid cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5575. doi:10.1158/1538-7445.AM2017-5575

The expression and significance of epithelial cellular adhesion molecule and Claudin-7 in thyroid cancer

Objective To investigate the expression and significance of epithelial cellular adhesion molecule (EpCAM) and Claudin-7 in thyroid cancer cells and tissues. Methods Papillary thyroid carcinoma cell line TPC-1, follicular thyroid carcinoma cell line FTC-133, and undifferentiated thyroid cancer cell lines FRO and ACT-1 were inoculated and incubated for 24 h. The mRNA levels of EpCAM and Claudin-7 in thyroid cancer cell lines were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Western blotting was used to investigate the protein levels of EpCAM and Claudin-7 in the thyroid cancer cells. The expressions of EpCAM and Claudin-7 in thyroid cancer cells were examined by fluorescence microscope. The expression levels of EpCAM and Claudin-7 in thyroid cancer tissues were tested by immunohistochemistry. Results The mRNA and protein expression levels of EpCAM and Claudin-7 were up-regulated in FRO and ACT-1 cells (Respectively, 18.7%, 29.6% and 81.5%, 70.0%), but there were few expression in TPC-1 and FTC-133 cells. Immunohistochemstry showed the results from fluorescence microscope was in accordance with those from RT-PCR and Western blotting. The postive expression rates of EpCAM and Claudin-7 in the other thyroid cancer cells were 2.6% and 5.2% sperately, and were 64.9% and 81.8% in undifferential thyroid cancer tissue. Conclusion EpCAM and Claudin-7 are highly expressed in undifferentiated thyroid carcinoma, which promotes the occurrence and development of thyroid carcinoma. Key words: Epithelial cellular adhesion molecule; Claudin-7; Thyroid cancer

8-Cl-cAMP and PKA I-selective cAMP analogs effectively inhibit undifferentiated thyroid cancer cell growth.

The main purpose of our work was to evaluate the effects of different cyclic adenosine monophosphate analogs on thyroid cancer-derived cell lines. In particular we studied 8-chloroadenosine-3',5'-cyclic monophosphate, the most powerful cyclic adenosine monophosphate analog, and the protein kinase A I-selective combination of 8-hexylaminoadenosine-3',5'cyclic monophosphate and 8-piperidinoadenosine-3',5'-cyclic monophosphate. The cyclic adenosine monophosphate/protein kinase A pathway plays a fundamental role in the regulation of thyroid cells growth. Site-selective cyclic adenosine monophosphate analogs are a class of cyclic adenosine monophosphate-derivate molecules that has been synthesized to modulate protein kinase A activity. Although the cyclic adenosine monophosphate/protein kinase A pathway plays a fundamental role in the regulation of thyroid cells proliferation, there are currently no studies exploring the role of cyclic adenosine monophosphate analogs in thyroid cancer. We evaluated the effects on cell proliferation, apoptosis activation and alterations of different intracellular pathways using 3-(4,5-dimetylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytofluorimetry, western blotting, and kinase inhibitors. Our results show that both compounds have antiproliferative potential. Both treatments were able to modify protein kinase A RI/RII ratio, thus negatively influencing cancer cells growth. Moreover, the two treatments differentially modulated various signaling pathways that regulate cell proliferation and apoptosis. Both treatments demonstrated interesting characteristics that prompt further studies aiming to understand the intimate interaction between different intracellular pathways and possibly develop novel anticancer therapies for undifferentiated thyroid cancer.

Abstract 3223: Androgen receptor stimulation decreases PD-L1 expression in androgen-responsive thyroid cancer cells

Abstract Women develop thyroid cancer more often than men; however, when men develop thyroid cancer, the disease course is more lethal, with a mortality rate that is two to three fold higher than in females. Immune elimination of nascent tumor cells may explain the differences in disease occurrence/course between men and women. To address this possibility, we examined the effect of androgen on the expression of immune checkpoint molecules in an androgen responsive-thyroid cancer cell line. The undifferentiated thyroid cancer cell line, 8505C, does not express a functional androgen receptor (AR). 84E7 is a clone of 8505C that was transfected with an AR containing plasmid resulting in constitutively expressed AR. Transcriptome analysis was performed on 8505C and 84E7, with and without 5α-dihydrotestosterone (DHT) treatment. Raw sequencing reads were aligned to the UCSC hg19 human reference genome with Tophat, and Cufflinks was used to measure transcript abundances in Reads Per Kilobase of exon model per Million mapped reads (RPKM) as well as to find genes with statistically significant changes in expression as per Trapnell et al (2012). RNASeq data indicated that DHT treatment of 8505C cells does not result in a significant change in gene expression (only 14 of 23,285 genes), consistent with the lack of a functional androgen receptor. In contrast, DHT treatment of 84E7 resulted in &amp;gt;2 fold expression changes in 1,552 genes. Examination of the immune checkpoint molecules CD28, CD80, CD86, CTLA-4, PD-1, PD-L1, PD-L2, TIM-3, TIM-3L, 4-1BB, 4-1BBL, OX40, and OX40L revealed that in DHT-treated 84E7 cells, PD-L1 was the sole immune checkpoint molecule that exhibited a significant expression change with a 1.8 log2 fold decrease (p = 0, q = 0), or 72% reduction in mRNA content. This is potentially significant as PD-L1 is produced by tumor cells as a strategy for subverting and evading the immune response, specifically T cells, allowing for continued tumor growth and metastases. In the thyroid, the presence of androgen-activated androgen receptors could perhaps lead to an environment that is more favorable for the immune system and may help eliminate nascent thyroid cancer cells. Thus, men may experience a decreased incidence of thyroid cancer due to an enhanced (less inhibited) anti-tumor environment. However, failure of this system and a subsequent increase in PD-L1 expression may help to explain the onset and severity of thyroid cancer in males. This finding opens the possibility for the use of immune checkpoint inhibitors in the treatment of thyroid cancer. Citation Format: Timmy O’Connell, Melanie Jones, Anvita Gupta, Augustine Moscatello, Raj K. Tiwari, Jan Geliebter. Androgen receptor stimulation decreases PD-L1 expression in androgen-responsive thyroid cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3223.

All-trans retinoic acid improves iodine uptake of thyroid cancer cells via repressing transcriptional activity of β-catenin

To determine whether all-trans retinoic acid (ATRA) could improve iodine uptake via repressing transcriptional activity of β-catenin in thyroid cancer cells. Three kinds of treatment models were firstly established with alcohol, ATRA, and transfection of β-catenin shRNA in undifferentiated human thyroid cancer cell line-SW1736.Then the expressions of sodium iodide symporter (NIS), β-catenin and its regulating factors, epithelial-mensechymal transition (EMT)-phenotype, invasion and metastasis associated proteins were further measured in above three cell models.After that, the influence of ATRA on the functional expression of NIS, iodine uptake potency, tumor growth curve and treatment effect inducing by radioactive iodine was comparatively analyzed in vitro and in vivo trials. After treated with ATRA, transcriptional activity of β-catenin decreased by downregulating phosphorylation of β-catenin Ser45, Y654 and GSK-3β Ser9. Additionally, ATRA effectively upregulated the protein level of NIS, and reversed EMT phenotype in alcohol treated cells, with absence in epithelial expression of E-cadherin and cytokeratin 18, as well as abnormal expression of Vimentin, urinary plasminogen activator (uPA), uPAR and Fibronectin.Compared with alcohol-treated group, both in vitro proliferation and invasion potential of ATRA treated cells markedly decreased (all P<0.05), and iodine uptake in vitro increased about 3.5-folds (P=0.007). In ATRA-treated animal model, tumor growth potential and tumor mass were significantly inhibited by radio-iodine ((131)I) treatment (all P<0.05). ATRA can increase functional expression of NIS via downregulating transcriptional activity of β-catenin and promote isotope sensitivity to radio-iodine in human undifferentiated thyroid cancer.

SP600125 has a remarkable anticancer potential against undifferentiated thyroid cancer through selective action on ROCK and p53 pathways.

Thyroid cancer is the most common endocrine malignancy with increasing incidence worldwide.The majority of thyroid cancer cases are well differentiated with favorable outcome. However, undifferentiated thyroid cancers are one of the most lethal human malignancies because of their invasiveness, metastatization and refractoriness even to the most recently developed therapies.In this study we show for the first time a significant hyperactivation of ROCK/HDAC6 pathway in thyroid cancer tissues, and its negative correlation with p53 DNA binding ability.We demonstrate that a small compound, SP600125 (SP), is able to induce cell death selectively in undifferentiated thyroid cancer cell lines by specifically acting on the pathogenic pathways of cancer development. In detail, SP acts on the ROCK/HDAC6 pathway involved in dedifferentiation and invasiveness of undifferentiated human cancers, by restoring its physiological activity level. As main consequence, cancer cell migration is inhibited and, at the same time, cell death is induced through the mitotic catastrophe. Moreover, SP exerts a preferential action on the mutant p53 by increasing its DNA binding ability. In TP53-mutant cells that survive mitotic catastrophe this process results in p21 induction and eventually lead to premature senescence. In conclusion, SP has been proved to be able to simultaneously block cell replication and migration, the two main processes involved in cancer development and dissemination, making it an ideal candidate for developing new drugs against anaplastic thyroid cancer.

Research progresses of CD133 in thyroid carcinoma

CD133 has been confirmed as a stem cell surface marker in a variety of tumors.Specific markers of cancer stem cells in the thyroid cancer are not yet clear.Results of some studies showed that expression of CD133 was found in undifferentiated thyroid cancer cells which had the characteristics of stem cells.Those cells had the ability to self-renewal,multi-directional differentiation,potential development to cancer,and radio-and chemotherapy resistance.This article mainly views the progresses of CD133 in thyroid cancer research. Key words: Thyroid neoplasms ; AC133 antigen; Trends

Biochemical effects of combined action of ?-irradiation and paclitaxel on anaplastic thyroid cancer cells

The aim of the paper was to describe the biochemical effects of Paclitaxel (Ptx), gamma-irradiation (IR) and their combination in undifferentiated thyroid cancer cells (ATC). IR activated common DNA damage-induced signaling and manifested certain mitogenic effect by inactivation of retinoblastoma protein (pRb). There was clear antagonism between Ptx and IR relative to cell cycle regulators--tumor suppressor p53, pRb, CHK2 and c-Abl as well as proapoptotic Bax expression, but combined action of both agents enhanced caspase-3 and, especially, caspase-8 activation. The Ptx at low (1-25 nM) concentrations caused noticeable radioprotective effect. Thus, in ATC cells the ionizing radiation and Ptx exhibited competitive effects upon phosphorylation of cell cycle controllers: p53, pRb, CHK2, cAbl and expression of Bax. At the same time, the combined effect of radiation and Ptx enhanced antiapoptotic Bcl-2 phosphorylation, caspases activation and survivin expression. The net effect of these events during the first 48-72 h of cells incubation can be considered as antiapoptotic--Ptx attenuated cytotoxic effect of IR.

The Effect of the Combined Action of Roscovitine and Paclitaxel on the Apoptotic and Cell Cycle Regulatory Mechanisms in Colon and Anaplastic Thyroid Cancer Cells

Aim. To study the significance of cyclin-dependent kinases (Cdks) in paclitaxel-dependent apoptosis in colon and undifferentiated thyroid cancer cells. Materials and Methods. Experiments were performed on undifferentiated thyroid carcinoma (KTC-2) and colon carcinoma (ARO) cell lines. Cells were treated with paclitaxel (Ptx) and inhibitor of Cdk, roscovitine. Cell survival test and Western blotting were used for characterization of the effects of paclitaxel and roscovitine on cancer cells. Results. It was shown that not c-Jun N-terminal kinase, but cyclin-dependent kinases are responsible for antiapoptotic Bcl-2 phosphorylation. Cdk inhibition enhanced the cytotoxic effects of Ptx at low drug concentrations. There was antagonism between Ptx and roscovitine at higher (25 nM) paclitaxel concentrations. Conclusion. Using of paclitaxel at low (2.5 to 5 nM) concentrations and roscovitine is a promising combination for further preclinical trials for the development of new therapeutic approaches to the treatment of colon and anaplastic thyroid cancer.

The effect of the combined action of roscovitine and Paclitaxel on the apoptotic and cell cycle regulatory mechanisms in colon and anaplastic thyroid cancer cells.

Aim. To study the significance of cyclin-dependent kinases (Cdks) in paclitaxel-dependent apoptosis in colon and undifferentiated thyroid cancer cells. Materials and Methods. Experiments were performed on undifferentiated thyroid carcinoma (KTC-2) and colon carcinoma (ARO) cell lines. Cells were treated with paclitaxel (Ptx) and inhibitor of Cdk, roscovitine. Cell survival test and Western blotting were used for characterization of the effects of paclitaxel and roscovitine on cancer cells. Results. It was shown that not c-Jun N-terminal kinase, but cyclin-dependent kinases are responsible for antiapoptotic Bcl-2 phosphorylation. Cdk inhibition enhanced the cytotoxic effects of Ptx at low drug concentrations. There was antagonism between Ptx and roscovitine at higher (25 nM) paclitaxel concentrations. Conclusion. Using of paclitaxel at low (2.5 to 5 nM) concentrations and roscovitine is a promising combination for further preclinical trials for the development of new therapeutic approaches to the treatment of colon and anaplastic thyroid cancer.

Reversine, a 2,6-disubstituted Purine, as an Anti-cancer Agent in Differentiated and Undifferentiated Thyroid Cancer Cells

A novel and effective treatment is urgently needed to deal with the current treatment dilemma in incurable differentiated thyroid cancer (DTC), poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC). Reversine, a small synthetic purine analogue (2,6-disubstituted purine), has been shown to be effective in tumor suppression. We performed in vitro evaluation of anti-tumor effects of reversine on proliferation, cell cycle, and apoptosis in human PDTC, ATC, and follicular thyroid cancer cell lines, respectively. Treatment of these three lines with reversine inhibited proliferation in a time- and dose-dependent manner. G2/M accumulation was demonstrated in cell cycle analysis. Reversine induced apoptosis in PDTC cells with caspase-3 and caspase-8 activation, but not caspase-9. Use of a pan-caspase inhibitor before treatment with reversine attenuated cell death. Reversine also showed in vivo growth inhibitory effects on ATC cells in a xenograft nude mice model. Data demonstrated that reversine is effective in inhibiting the growth of thyroid cancer cells by cell cycle arrest or apoptosis, especially with the more aggressive ATC and PDTC. Apoptosis was induced by the mitochondria-independent pathway. Reversine is therefore worthy of further investigation in clinical therapeutics.

Anti‐Proliferative Effects of Evodiamine on Human Thyroid Cancer Cell Line ARO

The incidence of thyroid cancer increases with age, and it is twice in women as common as in men. The undifferentiated thyroid cancer (UTC) is the most aggressive of all thyroid cancers. Unfortunately, there are almost no efficacious therapeutic modalities. It is important to develop some new effective therapies. Evodiamine is a chemical extracted from a kind of Chinese herb named Wu-Chu-Yu and has been demonstrated to be effective in preventing the growth of a variety of cancer cells. In the present study, the mechanism by which evodiamine inhibited the undifferentiated thyroid cancer cell line ARO was examined. Based on 3-(4,5-dimethylthiazol -2-yle)2,5-diphenyltetrazolium bromide (MTT) assay, cell proliferation rate was reduced dose-dependently by evodiamine, but not by rutaecarpine. According to the flow cytometric analysis, evodiamine treatment resulted in G2/M arrest and DNA fragmentation in ARO cells. The G2/M arrest was accompanied with an increase of the expression of cdc25C, cyclin B1, and cdc2-p161 protein, and it was also with a decrease of the expression of cdc2-p15. Furthermore, by using the TUNEL assay, evodiamine-induced apoptosis was observed at 48 h and extended to 72 h. Western blotting demonstrated that evodiamine treatment induced the activation of caspase-8, caspase-9, caspase-3, and the cleavage of poly ADP-ribose polymerase (PARP). These results suggested that evodiamine inhibited the growth of the ARO cells, arrested them at M phase, and induced apoptosis through caspases signaling.