Role of 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside in the Growth Regulation of Anaplastic Thyroid Cancer Cells Lines / 대한내분비학회지

BACKGROUND: Anaplastic thyroid carcinoma is one of the most aggressive human cancers with a median survival of only 6 months. Local surgical tumor debulking combined with radio-chemotherapy is generally used to treat this malady, but the low success rate has prompted the search for new therapeutic targets. We used 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) as an AMP-activated protein kinase (AMPK) activator to induce growth suppression and apoptosis in the anaplastic thyroid carcinoma cells. METHODS: We investigated the effect of AICAR on the proliferation of thyroid cancer cell lines (ARO, WRO and FRO) by performing methyl-thiazoletetrazolium bromide assay. We wanted to see the effect of AICAR on the apoptosis and cell cycle of the thyroid cancer cells, and we wanted to determine the mechanism of these changes. RESULTS: The proliferation of all thyroid cancer cell lines was significantly inhibited by administration of AICAR. FRO was the most susceptible cell line to AICAR treatment and so further studies were then performed with this cell line. The suppressive effect of AICAR on cell proliferation was related with phosphorylation of AMPK and the increased apoptosis. Also, cell cycle analysis revealed that progression to the G2-M phase was arrested (S-phase arrest) by AICAR treatment. S-phase arrest was associated with the increased protein expression of p21. CONCLUSION: In the anaplastic thyroid cancer cell lines, AICAR inhibited proliferation due to the arrest in the S-phase; this was accompanied with the increased expression of p21. Overall, AMPK activation by AICAR or any other pharmacological agent could be a tempting potential target for thyroid cancer therapy.

Role of Pexoxisome Proliferator Activated Receptor Gamma in Growth Regulation of Thyroid Cancer Cells / 대한내분비학회지

BACKGROUND: There is currently no effective option for the treatment of poorly differentiated thyroid carcinomas, so further studies are needed to evaluate new therapeutics. Thiazolinedione, an agonist of peroxisome proliferator activated receptor gamma (PPAR ), is known to suppress the growth of various tumor cell lines. This study was conducted to see if PPAR is involved in growth regulation of poorly differentiated thyroid cancer cells. SUBJECT AND METHODS: Thyroid cancer cell lines with a low degree differentiation, such as ARO and FRO cells were used, and their expression of PPAR mRNA checked. The effects of known agonists (rosiglitazone and 15-deoxy-delta12,14-prostglandin (15d-PGJ2)) and antagonists for PPAR (bisphenol A diglycidyl ether (BADGE)) on the growth of thyroid cancer cell lines expressing PPAR were evaluated by various methods, such as the methylthiazoletetrazolium bromide (MTT) assay, cell counts, and [3H]thymidine uptake. RESULTS: The expressions of PPAR were higher in ARO and FRO cells than in those of normal thyroid. Form the results of the MTT assay, the survival of ARO and FRO cells were found to decrease after administration of rosiglitazone or 15d-PGJ2. However, no change was observed after administration of BADGE. When the effect of rosiglitazone was evaluated by cell counting, there was significant decrease in number of ARO and FRO cells, but no change was observed after administration of 15d-PGJ2. Similar results were obtained using [3H]thymidine uptake. Thus, rosiglitazone treatment significantly decreased the [3H]thymidine uptake, whereas 15d-PGJ2 showed no significant effect. CONCLUSION: PPAR agonists (rosiglitazone and 15dPG-J2) suppressed the survival of ARO and FRO cells, undifferentiated thyroid cancer cell lines, with increased expressions of PPAR . However, the cell count and [3H] thymidine uptake were affected by rosiglitazone, but not by 15dPG-J2. This might suggest the antiproliferative effects of rosiglitazone are independent of PPAR ; and therefore, mediated by another unknown mechanism

Effect of Estrogen on H2O2 Induced Apoptosis of FRTL-5 Cells / 대한내분비학회지

BACKGROUND: Understanding the pathways and controlling mechanisms of thyrocyte apoptosis is important for the elucidation of the pathogenesis of goiter or thyroid cancer. A system for evaluating apoptosis, in FRTL-5 cells, triggered by hydrogen peroxide (H2O2), a highly likely apoptogenic signal in physiologic condition, was be set up to see the effects of TSH and estrogen on H2O2-induced apoptosis. METHOD: DNA laddering was used in the optimization process or the conditions of the set-up of system for the evaluation of apoptosis in the FRTL-5 cells. To quantify the apoptosis under the optimized conditions, histone-bound DNA fragments in the cytoplasm were measured by ELISA. RESULTS: 1) The optimized conditions for induction of apoptosis in the FRTL-5 cells by H2O2 were; observation of DNA laddering 18~24 hrs after the addition of 0.3 mM H2O2 to cells maintained in TSH-free, low serum containing media (5H1 or 5H0 media) for 48 hrs. 2) Exposure of the FRTL-5 cells to TSH (1 mU/L) for more than 48 hrs (6H0 media). before the addition of H2O2 significantly decreased the degree of apoptosis, compared to cells maintained under TSH-free conditions (0.98+/-0.21 vs. 2.27 0.11 arbitrary unit, p<0.05), whereas exposure for 24 hrs. did not. 3) Exposure of the FRTL-5 cells to high dose 17- estradiol (1-100 M) significantly decreased the degree of H2O2-induced apoptosis in a dose dependent manner. The addition of serum (1%) blunted the effects of estrogen on H2O2-induced apoptosis, and TSH totally abrogated the estrogen effect.Physiologic doses of estrogen (10~100 nM) showed no suppressive effects on H2O2-induced apoptosis in FRTL-5 cells. CONCLUSION: A system for evaluating apoptosis in FRTL-5 cells triggered by hydrogen peroxide (H2O2), a highly likely apoptogenic signal in physiologic condition, was set up, and found for the first time that high dose estrogen suppressed the H2O2-induced apoptosis in FRTL-5 cells

Effect of Estrogen on H2O2 Induced Apoptosis of FRTL-5 Cells / 대한내분비학회지

BACKGROUND: Understanding the pathways and controlling mechanisms of thyrocyte apoptosis is important for the elucidation of the pathogenesis of goiter or thyroid cancer. A system for evaluating apoptosis, in FRTL-5 cells, triggered by hydrogen peroxide (H2O2), a highly likely apoptogenic signal in physiologic condition, was be set up to see the effects of TSH and estrogen on H2O2-induced apoptosis. METHOD: DNA laddering was used in the optimization process or the conditions of the set-up of system for the evaluation of apoptosis in the FRTL-5 cells. To quantify the apoptosis under the optimized conditions, histone-bound DNA fragments in the cytoplasm were measured by ELISA. RESULTS: 1) The optimized conditions for induction of apoptosis in the FRTL-5 cells by H2O2 were; observation of DNA laddering 18~24 hrs after the addition of 0.3 mM H2O2 to cells maintained in TSH-free, low serum containing media (5H1 or 5H0 media) for 48 hrs. 2) Exposure of the FRTL-5 cells to TSH (1 mU/L) for more than 48 hrs (6H0 media). before the addition of H2O2 significantly decreased the degree of apoptosis, compared to cells maintained under TSH-free conditions (0.98+/-0.21 vs. 2.27 0.11 arbitrary unit, p<0.05), whereas exposure for 24 hrs. did not. 3) Exposure of the FRTL-5 cells to high dose 17- estradiol (1-100 M) significantly decreased the degree of H2O2-induced apoptosis in a dose dependent manner. The addition of serum (1%) blunted the effects of estrogen on H2O2-induced apoptosis, and TSH totally abrogated the estrogen effect.Physiologic doses of estrogen (10~100 nM) showed no suppressive effects on H2O2-induced apoptosis in FRTL-5 cells. CONCLUSION: A system for evaluating apoptosis in FRTL-5 cells triggered by hydrogen peroxide (H2O2), a highly likely apoptogenic signal in physiologic condition, was set up, and found for the first time that high dose estrogen suppressed the H2O2-induced apoptosis in FRTL-5 cells

Effect of LiCl on Iodine Kinetics in Thyroid Cancer Cell Lines Transduced by Recombinant Adenovirus Containing Sodium Iodide Symporter(NIS) Gene / 대한내분비학회지

BACKGROUND: Lithium is known to increase the retention of iodide in the thyroid gland, or in well differentiated thyroid cancer tissue. The effects of lithium on the function of the sodium iodide symporter (NIS) protein, especially when the lithium is increased in the retention of iodide in NIS-producing cells, the effect of lithium, on the kinetics of undifferentiated thyroid cancer cells transduced by a recombinant adenovirus containing the NIS gene, were checked. METHOD: Human NIS cDNA was inserted into pAxCAwt, a recombinant adenoviral cosmid vector, where the E1 & E2 genes have been deleted, making Rad-hNIS, which was propagated in 293 cells. The iodide uptake was evaluated by the 125I uptake assay in the undifferentiated thyroid cancer cells, ARO, FRO and NPA, following the infection with Rad-hNIS (1 or 10 MOI) in the presence, or absence, of LiCl at optimized concentrations. The iodide efflux was evaluated by the 125I efflux assay, for 1 hour, in the same cells expressing the NIS in the presence, or absence, of LiCl. Similar experiments were performed in the normal thyroid cell line, FRTL-5, cultured in 6H5 media. RESULTS: LiCl, at concentrations over 1.0mM, caused a significant decrease in the cell viability, as evaluated by trypan blue dye exclusion, in a dose dependent manner. When infected with Rad-hNIS, the iodide uptake was not affected by the LiCl in the ARO or NPA cells. However, LiCl(0.1and 1.0mM) increased the iodide uptake by 50 to 100%(vs. control) in the Rad-hNIS transduced FRO cells. In the Rad-hNIS transduced FRO cells, the iodide was released rapidly from the cells, with only 20.7+/-4.8% of the iodide uptake remaining at 1 hour, which was no different in the presence of LiCl (24.5+/-7.9%). The iodide efflux was not affected by the LiCl in the FRTL-5 cells cultured in the presence of TSH. CONCLUSION: These results suggest that the lithium-induced iodide retention in the thyroid gland, or in well differentiated thyroid cancer tissue, is not caused by the effect of the lithium on the NIS function, or the function of proteins or channels, involved in iodide transport via cell membranes. Although the iodide uptake can be markedly increased by the expression of NIS, with the transduction of Rad-hNIS, in undifferentiated thyroid cancer cells, the iodide taken up is rapidly released from the cells. A method for inducing the iodide retention in the cell should be elucidated in order to render the NIS gene therapy effective.