trichostatin-a and Carcinoma--Large-Cell

Lung cancer is the leading cause of cancer-related mortality and requires more effective molecular markers of prognosis and therapeutic responsiveness. Special AT-rich binding protein 1 (SATB1) is a global genome organizer that recruits chromatin remodeling proteins to epigenetically regulate hundreds of genes in a tissue-specific manner. Initial studies suggest that SATB1 overexpression is a predictor of poor prognosis in breast cancer, but the prognostic significance of SATB1 expression has not been evaluated in lung cancer.. A cohort of 257 lung cancers was evaluated by immunohistochemistry. Epigenetic silencing of SATB1 was examined in cell lines by 5-Aza 2-deoxycytidine and trichostatin A treatment, and chromatin immunoprecipitation.. Significant loss of SATB1 expression was found in squamous preinvasive lesions (p < 0.04) and in non-small cell lung cancers (p < 0.001) compared with matched normal bronchial epithelium. Loss of SATB1 independently predicted poor cancer-specific survival in squamous cell carcinomas (SCCs; hazard ratio: 2.06, 95% confidence interval: 1.2-3.7, p = 0.016). Treatment of lung cancer cell lines with the histone deacetylase inhibitor trichostatin A resulted in up-regulation of SATB1. SATB1 was associated with a decrease in the active chromatin mark acetylated histone H3K9 and an increase in the repressive polycomb mark trimethylated H3K27 in a SCC cell line relative to a normal bronchial epithelial cell line.. This is the first study showing that SATB1 expression is lost in early preinvasive squamous lesions and that loss of SATB1 is associated with poor prognosis in lung SCC. We hypothesize that the SATB1 gene is epigenetically silenced through histone modifications.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Antimetabolites, Antineoplastic; Azacitidine; Blotting, Western; Carcinoma, Large Cell; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Line, Tumor; Chromatin Immunoprecipitation; Cohort Studies; Decitabine; DNA Methylation; Epigenesis, Genetic; Female; Follow-Up Studies; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Immunoenzyme Techniques; Lung Neoplasms; Male; Matrix Attachment Region Binding Proteins; Middle Aged; Neoplasm Staging; Prognosis; Tissue Array Analysis

Lung cancer is the leading cause of cancer-related deaths in the United States due, in large part, to the lack of early detection methods. Lung cancer arises from a complex series of genetic and epigenetic changes leading to uncontrolled cell growth and metastasis. Unlike genetic changes, epigenetic changes, such as DNA methylation and histone acetylation, are reversible with currently available pharmaceuticals and are early events in lung tumorigenesis detectable by non-invasive methods. In order to better understand how epigenetic changes contribute to lung cancer, and to identify new disease biomarkers, we combined pharmacologic inhibition of DNA methylation and histone deacetylation in non-small cell lung cancer (NSCLC) cell lines, with genome-wide expression profiling. Of the more than 200 genes upregulated by these treatments, three of these, neuronatin, metallothionein 3 and cystatin E/M, were frequently hypermethylated and transcriptionally downregulated in NSCLC cell lines and tumors. Interestingly, four other genes, cylindromatosis, CD9, activating transcription factor 3 and oxytocin receptor, were dominantly regulated by histone deacetylation and were also frequently downregulated in lung tumors. The majority of these genes also suppressed NSCLC growth in culture when ectopically expressed. This study therefore reveals new putative NSCLC growth regulatory genes and epigenetic disease biomarkers that may enhance early detection strategies and serve as therapeutic targets.

Topics: Acetylation; Adenocarcinoma; Azacitidine; Biomarkers, Tumor; Carcinoma, Large Cell; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Chromatin Immunoprecipitation; Colony-Forming Units Assay; DNA Methylation; Enzyme Inhibitors; Epigenesis, Genetic; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Lung Neoplasms; Oligonucleotide Array Sequence Analysis; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured

The FEZ1/LZTS1 (FEZ1) gene, located on chromosome 8p22 (8p22), was identified recently as a candidate tumor suppressor gene. Because loss of heterozygosity at 8p21-22 is a frequent event in lung cancers, we studied FEZ1 alteration in short-term cultures of resected lung cancer tumors and cell lines.. We examined FEZ1 expression in 17 non-small cell lung cancer (NSCLC), 19 small cell lung cancer (SCLC) cell lines, and 6 pairs of short-term cultures of resected NSCLCs and accompanying nonmalignant bronchial cells (NBECs) by reverse transcription-PCR and Western blotting. To investigate the mechanism for silencing, cells were cultured with 5-aza-2'-deoxycytidine or trichostatin A. We screened for genomic mutations by PCR-single-strand conformational polymorphism.. Thirteen of 17 NSCLC (76%) and 3 of 19 SCLC (16%) of cell lines showed absent expression (P = 0.001). Of the paired NSCLC-NBEC cultures, 3 of 6 showed loss of expression in tumor cell cultures. In the cell lines retaining expression, the amplicon products in SCLCs were more intense than those of NSCLCs and NBECs. Expression of FEZ1 was not restored by 5-aza-2'-deoxycytidine and trichostatin A. Although FEZ1 expression was moderately correlated with loss of heterozygosity of specific microsatellite makers at 8p21-22 in NSCLC cell lines, it was strongly correlated to D8S261 and LPL loci in SCLC cell lines. No mutation was found within cording region of FEZ1 by PCR-single-strand conformational polymorphism.. We found differential FEZ1 expression in NSCLC and SCLC cell lines, and the absent expression in 3 of 6 short-term cultures of NSCLC tumors. FEZ1 may be related to tumorigenesis of lung cancer.

Topics: Adaptor Proteins, Signal Transducing; Adenocarcinoma; Azacitidine; Blotting, Western; Carcinoma, Large Cell; Carcinoma, Squamous Cell; Chromosomes, Human, Pair 8; CpG Islands; Decitabine; DNA Modification Methylases; DNA-Binding Proteins; DNA, Neoplasm; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Loss of Heterozygosity; Lung Neoplasms; Nerve Tissue Proteins; Polymorphism, Single-Stranded Conformational; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Cells, Cultured; Tumor Suppressor Proteins