trichostatin-a and Adenocarcinoma--Papillary

The purpose of this study was to investigate the effects of treating human thyroid cancer cell lines with demethylating agents and histone deacetylase (HDAC) inhibitors to see if they would downregulate expression and activity of the matrix metalloproteinases (MMP)-2 and MMP-9, resulting in inhibition of growth and invasion.. A total of 1 papillary cancer cell line (TPC-1) and 3 follicular thyroid cancer cell lines (FTC-133, FTC-236, and FTC-238) were treated with the demethylating agent 5-azacytidine (5-AZC) and the HDAC inhibitors trichostatin A (TSA) and valproic acid (VA). The activity of MMP proteins was determined using gelatin zymography, and commercially available assays were used to quantify growth inhibition and thyroid cancer cell invasion.. Treatment with TSA and VA resulted in decreased protein activity of MMP-2 and MMP-9 in all cell lines in a dose-dependent manner after 48 hours of treatment compared with untreated controls. In addition, 5-, TSA, and VA caused inhibition of growth in the range of 25-80% for all cell lines at 24, 48, and 72 hours. VA and TSA significantly decreased cell invasion in the FTC-133 and TPC-1 cell lines.. The HDAC inhibitors TSA and VA decreased the protein activity of MMP-2 and MMP-9 and, in combination with the demethylating agent 5-AZC, inhibited cellular growth in human papillary and follicular thyroid cancer cell lines. These results elucidate our understanding of the pathways affected by the demethylating agents and HDAC inhibitors, and provide further evidence that MMPs are a potentially useful target for molecular therapies in patients with aggressive or refractory thyroid cancers.

Topics: Adenocarcinoma, Follicular; Adenocarcinoma, Papillary; Antimetabolites, Antineoplastic; Azacitidine; Cell Line, Tumor; Drug Screening Assays, Antitumor; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Thyroid Neoplasms; Valproic Acid

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is an increasingly identified precursor to infiltrating ductal adenocarcinoma. Although our knowledge of the clinical and pathologic features of IPMNs is increasing, the molecular mechanisms underlying these neoplasms remain poorly understood.. To provide further insight into the molecular pathobiology of IPMNs, global expression profiling was done to determine genes that are inactivated/down-regulated in IPMNs using oligonucleotide microarrays (Affymetrix).. In total, 300 unique transcripts (217 known genes) were identified as highly underexpressed in 12 IPMNs (<10-fold lower and P < 0.05) compared with five normal pancreatic ductal epithelium samples obtained by laser capture microdissection. The differential expression of a selection of genes was confirmed using reverse-transcription PCR. One of the genes underexpressed at both the transcriptional and protein level in a significant proportion of IPMNs was the cyclin-dependent kinase inhibitor, CDKN1C/p57KIP2. CDKN1C expression was also decreased in many pancreatic cancer cell lines and was restored following treatment with a DNA methylation inhibitor (5-aza-2'-deoxycitidine) or, more potently, with a histone deacetylase inhibitor (trichostatin A). Partial methylation of the CDKN1C promoter CpG island was found in most, but not all, pancreatic cancer cell lines with reduced CDKN1C expression, and was also detectable in IPMNs. Furthermore, a subset of pancreatic cancers showed complete hypomethylation of LIT1, an imprinting control region important for the regulation of CDKN1C expression. Complete hypomethylation in these cancers was the result of deletion of the methylated LIT1 allele at 11p15.5 rather than loss of imprinting.. These findings suggest that CDKN1C is commonly down-regulated in pancreatic ductal neoplasms through a combination of promoter hypermethylation, histone deacetylation, and loss of the maternal allele expressing CDKN1C.

Topics: Adenocarcinoma, Mucinous; Adenocarcinoma, Papillary; Azacitidine; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cluster Analysis; Cyclin-Dependent Kinase Inhibitor p57; Decitabine; Down-Regulation; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Hydroxamic Acids; Immunohistochemistry; Oligonucleotide Array Sequence Analysis; Pancreatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction

We previously obtained gene expression profiles of 8 matched papillary thyroid carcinoma (PTC) and normal tissues using DNA microarrays. To identify novel tumor suppressor genes involved in thyroid carcinogenesis, we here analyze genes showing lower expression in PTC tumors than in normal thyroid tissues. A search for loss of heterozygosity (LOH) in 49 regions that harbor consistently down-regulated genes revealed LOH in only 4 regions and in just a very small number of tumors. To determine whether the underexpression might be due to promoter methylation, we used combined bisulfite restriction analysis and bisulfite sequencing to study 7 underexpressed genes. Loss of expression of MT1G and CRABP1 is accompanied by hypermethylation in the 5' regions of these genes, but methylation was not seen in other genes tested. Combined treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-Aza-dC) and the histone deacetylase inhibitor trichostatin A (TSA) resulted in demethylation and re-expression of the MT1G gene in the cell line K2. Treatment with 5-Aza-dC alone restored CRABP1 expression in a colorectal cancer cell line, SW48. In conclusion, LOH is a remarkably rare mechanism of loss of gene function in PTC. In contrast, hypermethylation of promoter CpG islands seems to occur at higher frequency. MT1G and CRABP1 are novel genes that are likely involved in the pathogenesis of sporadic PTC.

Topics: Adenocarcinoma, Papillary; Adult; Aged; Azacitidine; Base Sequence; CpG Islands; DNA Methylation; Enzyme Inhibitors; Female; Gene Expression Regulation, Neoplastic; Gene Silencing; Genes, Tumor Suppressor; Humans; Hydroxamic Acids; Loss of Heterozygosity; Male; Metallothionein; Microsatellite Repeats; Middle Aged; Molecular Sequence Data; O(6)-Methylguanine-DNA Methyltransferase; Polymerase Chain Reaction; Promoter Regions, Genetic; Receptors, Retinoic Acid; Thyroid Neoplasms; Tumor Cells, Cultured