Cell Growth Inhibition and Gene Expression Induced by the Histone Deacetylase Inhibitor, Trichostatin A, on Human Hepatoma Cells

Abstract

Objective: Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation in tumor cells. The effect of the HDAC inhibitor, trichostatin A (TSA), on hepatoma cells, however, has not been well studied. In this study, we examined cell viability and gene expression profile in hepatoma cell lines treated with TSA. Methods: To study cell growth inhibition and induction of apoptosis by TSA on human hepatoma cell lines including HuH7, Hep3B, HepG2, and PLC/PRF/5, cells were treated with TSA at various concentrations and analyzed by the 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively. Changes in gene expression profile after exposure to TSA were assessed using a cDNA microarray consisting of 557 distinct cDNA of cancer-related genes. The levels of acetylated histones were examined by the chromatin immunoprecipitation (ChIP) assay using anti-acetylated histone H3 or H4 antibody. Results: The MTT assay demonstrated that TSA showed cell growth inhibition not only in a concentration-dependent but also a time-dependent manner on all cell lines studied. The TUNEL assay also revealed the potential of TSA to induce apoptosis. The microarray analysis revealed that 8 genes including collagen type 1, α2 (COL1A2), insulin-like growth factor binding protein 2 (IGFBP2), integrin, α7 (ITGA7), basigin (BSG), quiescin Q6 (QSCN6), superoxide dismutase 3, extracellular (SOD3), nerve growth factor receptor (NGFR), and p53-induced protein (PIG11) exhibited substantial induction (ratio >2.0) after TSA treatment in multiple cell lines. ChIP assay, in general, showed a good correlation between the expression level of mRNA and levels of acetylated histones in these upregulated genes. Conclusions: This study showed cell growth inhibition and the gene expression profile in hepatoma cell lines exposed to TSA. The alteration in levels of acetylated histones was closely associated with expression of specific cancer-related genes in hepatoma cells.

Side population purified from hepatocellular carcinoma cells harbors cancer stem cell-like properties

“…In this study, we estimated whether SP cells purified from four HCC cell lines, showing different clinical characteristics, 27 than 1% of total cells could be detected in Huh7 and PLC/PRF/5 cells; however, HepG2 and Huh6 cells lacked the subpopulation. HepG2 and Huh6 cells scarcely showed changes in flow cytometry analysis patterns, even when stained with an increased dose of Hoechst dye.…”

Differential regulation of connective tissue growth factor in renal cells by histone deacetylase inhibitors

“…Gene expression profiling of HDI-treated cancer cells provided conflicting data. Most array data did not suggest CTGF to be regulated by HDACs, whereas variable up-regulation was observed in certain hepatoma cell lines [27]. Gray [28].…”

Histone deacetylase inhibitors and genomic instability

“…However, potential downstream targets of HDACIs include various aspects of the cell cycle, DNA recombination and repair, extrinsic and intrinsic apoptosis pathways, angiogenesis, autophagy and senescence, among others; and it is not clear whether transcription mediates HDACI action in these processes [32]. Only a relatively small proportion of genes are up-or down-regulated following treatment with the HDACIs TSA [33][34][35] …”