In Vitro Effects of Boric Acid on Cell Cycle, Apoptosis, and miRNAs in Medullary Thyroid Cancer Cells.

Medullary thyroid cancer (MTC) is a highly aggressive and chemotherapy-resistant cancer originating from the thyroid's parafollicular C cells. Due to its resistance to conventional treatments, alternative therapies such as boric acid have been explored. Boric acid, a boron-based compound, has shown anticarcinogenic effects, positioning it as a potential treatment option for MTC. TT medullary thyroid carcinoma cell line (TT cells) and human thyroid fibroblast (HThF cells) were utilized for the cell culture experiments. Cell viability was assessed using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Total RNA was extracted using Trizol reagent for gene expression and microRNA (miRNA) analysis via reverse transcription-polymerase chain reaction (RT-PCR). The extent of apoptosis induced by boric acid was determined using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Colony formation assays were conducted to evaluate the impact of boric acid on the colony-forming ability of MTC cells. At 48 h, 50% inhibitory concentration (IC50) of boric acid was found to be 35 µM. Treatment with boric acid resulted in significant modulation of apoptosis-related genes and miRNAs, including increased expression of phorbol-12-myristate-13-acetate-induced protein 1(NOXA), apoptotic protease activating factor 1 (APAF-1), Bcl-2-associated X protein (Bax), caspase-3, and caspase-9. In contrast, the expression of B cell lymphoma 2 (Bcl2), B cell lymphoma- extra-large (Bcl-xl), and microRNA-21 (miR-21), which are linked to the aggressiveness of MTC, was significantly reduced. The TUNEL assay indicated a 14% apoptosis rate, and there was a 67.9% reduction in colony formation, as shown by the colony formation assay. Our study suggests that boric acid may have anticancer activity in MTC by modulating apoptotic pathways. These findings suggest that boric acid could be a potential therapeutic agent for MTC and possibly for other malignancies with similar pathogenic mechanisms.

TT-1, an analog of melittin, triggers apoptosis in human thyroid cancer TT cells via regulating caspase, Bcl-2 and Bax.

Melittin is a 26 amino acid residue antimicrobial peptide with known antitumor activity. In the present study, a novel peptide TT-1, derived from melittin and contained only 11 amino acids, was designed, and its antitumor effect was investigated. The present study is aimed to elucidate the effects and relative mechanisms of TT-1 on a human thyroid cancer cell line (TT) in vitro and in vivo. Cell viability assays, Annexin V/propidium iodide assays, western blotting and quantitative reverse transcription polymerase chain reaction were performed. Furthermore, a tumor-xenograft model was established to investigate the apoptotic mechanisms of TT-1 on TT cells. The results obtained indicated that TT-1 was able to suppress the proliferation of TT cells and exhibited low cytotoxicity to normal thyroid cells in vitro. The apoptotic rates of TT cells were also increased following TT-1 treatment. Additionally, TT-1 stimulated caspase-3, caspase-9 and Bax, and inhibited B-cell lymphoma 2 mRNA and protein expression. Finally, it was also demonstrated that TT-1 is able to markedly suppress tumor growth in a TT-bearing nude mouse model. In summary, TT-1 may inhibit the proliferation of TT cells by inducing apoptosis in vitro and in vivo, indicating that TT-1 may be a potential candidate for the treatment of thyroid cancer.

Anti-tumor effects of shikonin derivatives on human medullary thyroid carcinoma cells.

New treatment options are needed for medullary thyroid carcinoma (MTC), a highly metastasizing neuroendocrine tumor that is resistant to standard radiotherapy and chemotherapy. We show that the following shikonin derivatives inhibit cell proliferation and cell viability of the MTC cell line TT: acetylshikonin, ß,ß-dimethylacrylshikonin, shikonin and a petroleum ether extract of the roots of Onosma paniculata containing several shikonin derivatives. The unsubstituted shikonin derivative was found to be the most effective compound with an IC50 of 1.1 µM. The cell viability of normal human skin fibroblasts, however, was not affected by the tested substances, indicating that shikonin derivatives might be selectively toxic for cancer cells. We further report that migration and invasion of TT cells were inhibited at non-toxic concentrations. Finally, shikonin was tested in vivo using the chick chorioallantoic membrane assay, where it significantly reduced tumor growth by inhibiting cell proliferation and inducing apoptosis. In summary, our results suggest that shikonin derivatives have the potential for the treatment of medullary thyroid carcinomas.

Anti-proliferative and anti-invasive effects of ferulic acid in TT medullary thyroid cancer cells interacting with URG4/URGCP.

Ferulic acid (4-hydroxy-3-methoxycinnamic acid; FA), a common dietary plant phenolic compound, is abundant in fruits and vegetables. The aim of present study is to investigate the effects of FA on cell cycle, apoptosis, invasion, migration, and colony formation in the TT medullary thyroid cancer cell line. The effect of FA on cell viability was determined by using CellTiter-Glo assay. IC50 dose in the TT cells was detected as 150 µM. URG4/URGCP (upregulated gene-4/upregulator of cell proliferation) is a novel gene in full-length mRNA of 3.607 kb located on 7p13. It was determined that FA caused a decrease in the expression of novel gene URG4/URGCP, CCND1, CDK4, CDK6, BCL2, MMP2, and MMP9, a significant increase in the expression of p53, PARP, PUMA, NOXA, BAX, BID, CASP3, CASP9, and TIMP1 genes in TT human thyroid cancer cell line by using real-time PCR. It was found that FA in TT cells suppressed invasion, migration, and colony formation by using matrigel invasion chamber, wound healing, and colony formation assay, respectively. In conclusion, it is thought that FA indicates anticarcinogenesis activity by affecting cell cycle arrest, apoptosis, invasion, migration, and colony formation on TT cells.

Effect of BMAP-28 on human thyroid cancer TT cells is mediated by inducing apoptosis.

Thyroid cancer is the most common malignant endocrine tumor, with significant morbidity and mortality. Bovine myeloid antimicrobial peptide 28 (BMAP-28) is a cathelicidin that is found in bovine neutrophils. In the present study, the effect and relative mechanism of BMAP-28 on the human thyroid cancer TT cell line in vitro and in vivo were investigated. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and a TT-xenograft mouse model were used in this study. The data obtained indicated that BMAP-28 significantly inhibited the proliferation of the TT cells in vitro. In addition, the Annexin V-fluorescein isothiocyanate/propidium iodide assay detected that BMAP-28 induced apoptotic effects in the TT cells. Moreover, the expression of activated caspase-3 and -9 was upregulated at the transcriptional and translational levels. Simultaneously, the expression of matrix metalloproteinase (MMP)3 and MMP9 was downregulated following BMAP-28 treatment. Finally, BMAP-28 significantly prevented the tumor growth in the TT-xenograft mouse model. These results indicated that BMAP-28 could be a potential agent for the treatment of thyroid cancer.

Apoptosis induction by combination of drugs or a conjugated molecule associating non-steroidal anti-inflammatory and nitric oxide donor effects in medullary thyroid cancer models: implication of the tumor suppressor p73.

BACKGROUND: Medullary thyroid cancer (MTC) is a C-cell neoplasm. Surgery remains its main treatment. Promising therapies based on tyrosine kinase inhibitors demand careful patient selection. We previously observed that two non-steroidal anti-inflammatory drugs (NSAID), indomethacin, celecoxib, and nitric oxide (NO) prevented tumor growth in a model of human MTC cell line (TT) in nude mice. METHODS: In the present study, we tested the NO donor: glyceryl trinitrate (GTN), at pharmacological dose, alone and in combination with each of the two NSAIDs on TT cells. We also assessed the anti-proliferative potential of NO-indomethacin, an indomethacin molecule chemically conjugated with a NO moiety (NCX 530, Nicox SA) on TT cells and indomethacin/GTN association in rMTC 6-23 cells. The anti-tumoral action of the combined sc. injections of GTN with oral delivery of indomethacin was also studied on subcutaneous TT tumors in nude mice. Apoptosis mechanisms were assessed by expression of caspase-3, TAp73α, TAp73α inhibition by siRNA or Annexin V externalisation. RESULTS: The two NSAIDs and GTN reduced mitotic activity in TT cells versus control (cell number and PCNA protein expression). The combined treatments amplified the anti-tumor effect of single agents in the two tested cell lines and promoted cell death. Moreover, indomethacin/GTN association stopped the growth of established TT tumors in nude mice. We observed a significant cleavage of full length PARP, a caspase-3 substrate. The cell death appearance was correlated with a two-fold increase in TAp73α expression, with inhibition of apoptosis after TAp73α siRNA addition, demonstrating its crucial role in apoptosis. CONCLUSION: Association of NO with NSAID exhibited amplified anti-tumoral effects on in vitro and in vivo MTC models by inducing p73-dependent apoptotic cell death.

The expression of the truncated isoform of somatostatin receptor subtype 5 associates with aggressiveness in medullary thyroid carcinoma cells.

The truncated somatostatin receptor variant sst5TMD4 associates with increased invasiveness and aggressiveness in breast cancer. We previously found that sst5 activation may counteract sst2 selective agonist effects in a medullary thyroid carcinoma (MTC) cell line, the TT cells, and that sst5TMD4 is overexpressed in poorly differentiated thyroid cancers. The purpose of this study is to evaluate sst5TMD4 expression in a series of human MTC and to explore the functional role of sst5TMD4 in TT cells. We evaluated sst5TMD4 and sst5 expression in 36 MTC samples. Moreover, we investigated the role of sst5TMD4 in TT cells evaluating cell number, DNA synthesis, free cytosolic calcium concentration ([Ca(2+)]i), calcitonin and vascular endothelial growth factor levels, cell morphology, protein expression, and invasion. We found that in MTC the balance between sst5TMD4 and sst5 expression influences disease stage. sst5TMD4 overexpression in TT cells confers a greater growth capacity, blocks sst2 agonist-induced antiproliferative effects, modifies the cell phenotype, decreases E-cadherin and phosphorylated ß-catenin levels, increases vimentin, total ß-catenin and phosphorylated GSK3B levels (in keeping with the development of epithelial to mesenchymal transition), and confers a greater invasion capacity. This is the first evidence indicating that sst5TMD4 is expressed in human MTC cells, where it associates with more aggressive behavior, suggesting that sst5TMD4 might play a functionally relevant role.

Effects of small hairpin RNA-mediated S100A13 gene inhibition on the release of fibroblast growth factor-1 in human thyroid cancer cells / 中华内分泌代谢杂志

Objective To investigate whether the release of fibroblast growth factor-1 ( FGF-1 ) was changed after inhibition of S100A13 gene (small hairpin RNA, shRNA)and serum-deprivation in human thyroid cancer cells (TT cells ). Methods The S100A13-shRNA pENTRTM/U6 entry vector was transfected into TT cells. The expression of S100A13 mRNA and protein was detected by immunoflurescence, real-time RT-PCR, and Western blot. Then TT cells were treated with S100A13 gene inhibition and serum-deprivation. The changes in release of FGF-1 were detected by indirect immunoflurescence, RT-PCR, and ELISA. Results S100A13 shRNA transfected TT cells (S100A13 RNAi cells)had a reduction of S100A13 gene and protein expression by 80%.Indirect immunofluorescence indicated FGF-1 was mostly localized in the cytoplasm and nucleus of TT cells in primary culture. When serum-deprivation stress was given to TT cells, FGF-1 in cytoplasm almost disappeared in the cells at 6 h. RT-PCR indicated that when serum-deprivation stress was given to TT cells the mRNA of FGF-1 was reduced. ELISA showed that with inhibition of S100A13, the release of FGF-1 was reduced (P＜0.05).Conclusion S100A13-shRNA pENTRTM/U6 entry vector transfected TT cells may inhibit the expression of S100A13 and reduce the release of FGF-1.