trichostatin-a and Thyroid-Carcinoma--Anaplastic

The influence of the heat shock protein 90 (hsp90) inhibitor SNX5422 alone or in combination with the histone deacetylase (HDAC) inhibitors PXD101, suberoylanilide hydroxamic acid (SAHA), and trichostatin A (TSA) on survival of anaplastic thyroid carcinoma (ATC) cells was investigated. In 8505C and CAL62 cells, SNX5422 caused cell death with concomitant changes in the expression of hsp90 client proteins. After treatment of both SNX5422 and PXD101, SAHA and TSA, compared with treatment of SNX5422 alone, cell viability was diminished, whereas inhibition rate and cytotoxic activity were enhanced. All of the combination index values were lower than 1.0, suggesting the synergism between SNX5422 and PXD101, SAHA and TSA in induction of cell death. In cells treated with both SNX5422 and PXD101, SAHA and TSA, compared with cells treated with SNX5422 alone, the protein levels of Akt, phospho-4EBP1, phospho-S6 K, and survivin were diminished, while those of γH2AX, acetyl. histone H3, acetyl. histone H4, cleaved PARP, and cleaved caspase-3 were enhanced. In conclusion, these results demonstrate that SNX5422 has a cytotoxic activity in conjunction with alterations in the expression of hsp90 client proteins in ATC cells. Moreover, SNX5422 synergizes with HDAC inhibitors in induction of cytotoxicity accompanied by the suppression of PI3K/Akt/mTOR signaling and survivin, and the overexpression of DNA damage-related proteins in ATC cells.

Topics: Antineoplastic Agents; Apoptosis; Benzamides; Caspase 3; Cell Line, Tumor; Cell Survival; Drug Synergism; Glycine; Histone Deacetylase Inhibitors; HSP90 Heat-Shock Proteins; Humans; Hydroxamic Acids; Indazoles; Phosphorylation; Proto-Oncogene Proteins c-akt; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Vorinostat

Anaplastic thyroid cancer cells are characterized by a mesenchymal phenotype, as revealed by spindle-shaped cells and absent or reduced levels of E-cadherin. Epigenetic silencing is considered one of the leading mechanisms of E-cadherin impairment, which causes the acquisition of the invasive and metastatic phenotype of anaplastic thyroid cancer.. In this study we investigated the effects of histone deacetylase inhibition on E-cadherin expression, cell motility, and invasion in anaplastic thyroid cancer cell cultures.. Three stabilized cell lines and primary cultures of anaplastic thyroid cancer were treated with various histone deacetylase inhibitors. After treatment, we evaluated histone acetylation by Western blotting and E-cadherin expression by RT-real time PCR. The proper localization of E-cadherin/β-catenin complex was assessed by immunofluorescence and Western blot. Transcription activity of β-catenin was measured by luciferase reporter gene and cyclin D1 expression. The effect on cell motility and invasion was studied both in vitro using scratch-wound and transwell invasion assays and in anaplastic thyroid carcinomas tumor xenografts in mice in vivo.. Histone deacetylase inhibition induced the E-cadherin expression and the proper membrane localization of the E-cadherin/β-catenin complex, leading to reduced cancer cell migration and invasion.. We here demonstrate an additional molecular mechanism for the anticancer effect of histone deacetylase inhibition. The antiinvasive effect in addition to the cytotoxic activity of histone deacetylase inhibitors opens up therapeutic perspectives for the anaplastic thyroid tumor that does not respond to conventional therapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Benzamides; beta Catenin; Cadherins; Cell Movement; Down-Regulation; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Mice; Mice, SCID; Neoplasm Invasiveness; Panobinostat; Protein Transport; Pyridines; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Prohibitin (PHB) is a ubiquitous protein with a number of different molecular functions. PHB is involved in tumorigenesis by exerting either a permissive or blocking action on tumor growth, depending on the cell context. In the present study, we investigated the effects of the histone deacetylase inhibitors (HDACis), trichostatin A (TSA) and sodium butyrate (NaB), on PHB expression in the thyroid tumor cell lines, TPC-1 and FRO. Both TSA and NaB increased PHB mRNA levels. Transfection experiments showed that the overexpression of HDAC1 or 2, but not 3, inhibited PHB promoter activity. The effects of TSA and NaB on the two major PHB mRNA splicing isoforms, were also investigated. Both TSA and NaB decreased the mRNA levels of the shorter isoform, but increased those of the longer isoform. Only the latter isoform contains a 3'UTR, which has been reported to exert a growth suppressive action. Thus, our data demonstrate that HDACis control both PHB transcription and alternative splicing. The effect of HDACis on PHB alternative splicing was not due to the modification of the expression of the ASF/SF2 splicing factor.

Topics: Alternative Splicing; Carcinoma, Papillary, Follicular; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Models, Biological; Prohibitins; Promoter Regions, Genetic; Repressor Proteins; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Transcription, Genetic; Transfection