trichostatin-a and Tongue-Neoplasms

The present in vitro study aims to investigate the potential use of epigenetic inhibitors as treatment modalities in tongue squamous cell carcinoma.. The human tongue squamous cell carcinoma cell line (CAL-27) was cultured and exposed to varying concentrations of 5-Azacitidine (5-Aza) or Trichostatin A (TSA) in the culture medium. The cell apoptosis was evaluated using Annexin V/PI by flow cytometry. To evaluate DNA damage response, γH2AX foci analysis was performed using immunofluorescence. Single cell gel electrophoresis (SCGE) was applied to measure DNA strand breaks. Gene expression was assessed by quantitative real-time PCR.. The results showed that 5-Aza and TSA had apoptotic effects on the SCC cell line at concentrations of 50-200 µM and 0.5-5 µM, respectively. Immunofluorescence analysis showed increased expression of γH2AX, the marker of DNA damage response after treatment of 5-Aza and TSA that was associated with increased DNA strand breaks. The expressions of urokinase plasminogen activator, its receptor and matrix metalloproteinase-2, were significantly reduced in TSA- and 5-Aza-treated cells.. Our results showed that 5-Aza and TSA increase apoptotic and DNA damage response in squamous cell carcinoma cell line while reducing the expression of tumor invasion genes that further indicating the potential therapeutic value of two epigenetic modifiers in squamous cell carcinoma.

Topics: Azacitidine; Carcinoma, Squamous Cell; Decitabine; DNA Damage; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Matrix Metalloproteinase 2; Tongue; Tongue Neoplasms

Trichostatin A (TSA), a histone deacetylase inhibitor, is used as an anti-carcinogenic and radiosensitizing agent in various cancers. However, the role and mechanism underlying its radiosensitization of tongue squamous cell carcinoma (TSCC) remains unclear. Thus, in this study we aimed to confirm the promotion of miR‑375 expression by TSA, and to investigate the effects of TSA and miR‑375 in the radiosensitivity of TSCC cells. The results showed that TSA had significant radiosensitizing effects on TSCC cells and miR‑375 overexpression had effects similar to TSA in sensitizing these cells to radiotherapy. By contrast, miR‑375 knockdown attenuated apoptosis induced by radiation combined with TSA. Mechanistically, the histone acetylation status of the miR‑375 promoter region was increased by TSA, resulting in the upregulation of miR‑375, which led to a decline of PDK1 and phosphorylated AKT. Taken together, our data suggest that TSA increases the radiosensitization and apoptosis in TSCC cells at least partially via miR‑375, and TSA or miR‑375 in combination with radiotherapy may provide a valuable approach for the treatment of TSCC.

Topics: Apoptosis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; MicroRNAs; Phosphorylation; Promoter Regions, Genetic; Proto-Oncogene Proteins c-akt; Radiation-Sensitizing Agents; Tongue Neoplasms

Hypoxia is an essential feature of the microenvironment of solid tumors, which regulates a variety of transcription factors including hypoxia-inducible factor-1α (HIF-1α). HIF-1α overexpression enhances tumor angiogenesis via upregulation of vascular endothelial growth factor (VEGF) and some other hypoxia-inducible angiogenic factors, which lead to a more aggressive tumor phenotype, tumor metastasis and resistance to radiation and chemotherapy. In this study, we found that a histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), inhibited cell proliferation and invasion, blocked the cell cycle, and induced cell apoptosis in a dose- and time-dependent manner in the human tongue squamous cell carcinoma (TSCC) SCC-6 cell line in vitro. Furthermore, TSA reduced both basal levels and hypoxia-induced HIF-1α protein accumulation but not HIF-1α mRNA levels, and both protein and mRNA levels of VEGF expression. These results showed that TSA had a potent anticancer activity on TSCC cells, suggesting that TSA could be a promising drug targeting tumor angiogenesis via inhibition of HIF-1α and VEGF expression in the development of an effective chemopreventive and anticancer agent on human TSCCs.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle Checkpoints; Cell Hypoxia; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Hypoxia-Inducible Factor 1, alpha Subunit; Tongue Neoplasms; Vascular Endothelial Growth Factor A

Histone deacetylases (HDACs) inhibitors induce cell growth arrest and apoptosis in a wide variety of tumor cells. The purpose of this study was to evaluate the effects of trichostatin A (TSA), one of the HDACs inhibitors, on proliferation and apoptosis of oral squamous cell carcinoma cells. Exposure of Tca83 cells (established from human tongue squamous cell carcinoma) to TSA resulted in cell growth inhibition and apoptosis in a dose-dependent manner as measured with MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay and DAPI (4'6'diamidino-2-phenylindole dihydrochloride) staining. Western blot showed that both total PTEN and membrane-bound PTEN were induced by TSA treatment, whereas phosphorylation level (Ser 473) of AKT was correspondingly down-regulated by TSA treatment. Knock-down of PTEN expression with PTEN siRNA could sufficiently block 0.25mug/ml TSA induced inhibition of cell growth, but failed to block 0.5mug/ml TSA induced inhibition of cell growth and apoptosis. Moreover, induction of apoptosis by TSA treatment was also demonstrated by cytochrome C releasing and induction of caspase-3. Conclusively, the results suggested that PTEN/AKT pathway was involved in TSA induced cell growth inhibition and apoptosis of oral squamous cell carcinoma cells. HDACs inhibitors could be potential anticancer drugs for chemotherapy of oral squamous cell carcinoma.

Topics: Apoptosis; Blotting, Western; Carcinoma, Squamous Cell; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Neoplasm Proteins; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Thiazoles; Tongue Neoplasms

The HDAC inhibitor Trichostatin A (TSA) exhibits antitumour activity in various tumour cells. However, little is known about the effect of TSA on growth of human tongue carcinoma cells. In this study, we observed that TSA concentration-dependently inhibited growth of human tongue carcinoma Tca8113 cells by inducing G2/M arrest, apoptosis, up-regulation of the pro-apoptotic protein Bax and down-regulation of the anti-apoptotic proteins Bcl-2 and Bcl-XL which are regulated by the transcription factor nuclear factor (NF)-kappaB. Coincident with this observation, TSA induced a concentration-dependent reduction of constitutive and tumour necrosis factor (TNF)-alpha-induced NF-kappaB activation in Tca8113 cells. This induction was correlated with decreased phosphorylation and increased expression of inhibitors of NF-kappaB (IkappaB)alpha induced by TSA. Overall, our results indicate inhibition of NF-kappaB activation contributes, at least partially, to the antitumour activity of TSA in human tongue carcinoma cells.

Topics: Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Benzimidazoles; Blotting, Western; Carcinoma; Cell Cycle; Cell Division; Cell Line, Tumor; Down-Regulation; Electrophoretic Mobility Shift Assay; Flow Cytometry; Fluorescent Dyes; G2 Phase; Genes, bcl-2; Humans; Hydroxamic Acids; NF-kappa B; Phosphorylation; Protein Synthesis Inhibitors; Signal Transduction; Tongue Neoplasms; Tumor Necrosis Factor-alpha