This study investigated the inhibitory effects of curcumin on proliferation of hematological malignant cells in vitro and the anti-tumor mechanism at histone acetylation/histone deacetylation levels. The effects of curcumin and histone deacetylase inhibitor trichostatin A (TSA) on the growth of Raji cells were tested by MTT assay. The expression of acetylated histone-3 (H(3)) in Raji, HL60 and K562 cells, and peripheral blood mononuclear cells (PBMCs) treated with curcumin or TSA was detected by immunohistochemistry and FACS. The results showed curcumin inhibited proliferation of Raji cells significantly in a time- and dose-dependent fashion, while exhibited low toxicity in PBMCs. Curcumin induced up-regulation of the expression of acetylated H(3) dose-dependently in all malignant cell lines tested. In conclusion, curcumin inhibited proliferation of Raji cells selectively, enhanced the level of acetylated (H(3)) in Raji, HL60, and K562 cells, which acted as a histone deacetylase inhibitor like TSA. Furthermore, up-regulation of H(3) acetylation may play an important role in regulating the proliferation of Raji cells.
Acetylation/drug effects ; Antineoplastic Agents/*pharmacology ; Cell Proliferation/*drug effects ; Curcumin/*pharmacology ; HL-60 Cells ; Histone Deacetylase Inhibitors/pharmacology ; Histones/chemistry ; Histones/*drug effects ; K562 Cells ; Triclosan/pharmacology

OBJECTIVETo investigate the effects of PHI on histone acetylation and methylation in hepatocellular carcinoma line SMMC-7721 cells.

METHODSApoptosis was measured by TUNNEL assay. Histone methylation and acetylation were detected by Western blot.

RESULTSPHI inhibited cells growth and induced apoptosis. PHI treatment resulted in increased acetylation of histone H3 and H4 , elevated level of histone H3 lysine 4 methylation, and decreased level of histone H3 lysine 9 methylation.

CONCLUSIONSPHI can modulate both histone acetylation and methylation, which could remodel chromatin structure. PHI may be a novel anticancer drug.

Acetylation ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Histones ; metabolism ; Humans ; Isothiocyanates ; pharmacology ; Methylation

OBJECTIVETo investigate the effect of trichostatin A(TSA) on SGC- 7901 cells.

METHODSCytotoxicity and cell viability of gastric cancer cell line SGC- 7901 were assayed by MTT method. Morphologic assessment of apoptosis was performed with fluorescence microscope. Cell cycle and apoptosis rate were analyzed by flow cytometry. Histone H3 acetylation was detected by Western blot.

RESULTSTSA showed apparently cytotoxicity in SGC- 7901 cells. The growth curve showed the growth ratio decreased with the increase of TSA concentration. Apoptosis rate were significantly different between TSA treated group(75 ng/ml for 72 h)and control group (P < 0.05). Morphologic changes of apoptosis including nuclear chromatin condensation and fluorescence strength were observed with fluorescence microscope.TSA treatment (75 ng/ml for 72 h) sensitively induced apoptosis in the cell,which was demonstrated by the migration of many cells to the sub- G1 phase,the reduction of G1- phase cells and the increment of apoptosis rate (29.54%) in flow cytometric analysis. The expression of acetylated histone H3 was increased in TSA group(75 ng/ml) for 48 h compared with control group by Western blot.

CONCLUSIONSTSA can induce SGC- 7901 cell apoptosis. The expression of acetylated histone H3 may contribute to the apoptosis.

Acetylation ; drug effects ; Apoptosis ; drug effects ; Cell Line, Tumor ; Histones ; metabolism ; Humans ; Hydroxamic Acids ; pharmacology ; Stomach Neoplasms

This study was purposed to investigate the effects of phenylhexyl isothiocyanate (PHI) on Burkitt lymphoma Daudi cell line and regulation of histone acetylation and methylation in Daudi cells, and to explore the potential mechanism. The apoptotic rate of Daudi cells treated with PHI was measured by flow cytometry, the changes of histone H3 and H4 acetylation, histone H3K9 and H3K4 methylation in Daudi cells treated with PHI were detected by Western blot. The results showed that PHI could induce apoptosis of Daudi cells, increased the acetylation level of H3 and H4, enhanced the methylation of H3K4, but reduced the methylation of H3K9. It is concluded that the PHI can up-regulate the acetylation level of histone H3 associated with transcription stimulation and the methylation of histone H3K4, down-regulate the methylation on histone H3K9 associated with transcription inhibition, promotes the apoptosis of Daudi cells. PHI may be a potential agent for target therapy of lymphoma.
Acetylation ; Apoptosis ; drug effects ; Burkitt Lymphoma ; genetics ; metabolism ; Cell Line, Tumor ; Histones ; genetics ; metabolism ; Humans ; Isothiocyanates ; pharmacology ; Methylation

There are large knowledge gaps regarding how to control stem cells growth and differentiation. The limitations of currently available technologies, such as growth factors and/or gene therapies has led to the search of alternatives. We explore here how a cell's epigenome influences determination of cell type, and potential applications in tissue engineering. A prevalent epigenetic modification is the acetylation of DNA core histone proteins. Acetylation levels heavily influence gene transcription. Histone deacetylase (HDAC) enzymes can remove these acetyl groups, leading to the formation of a condensed and more transcriptionally silenced chromatin. Histone deacetylase inhibitors (HDACis) can inhibit these enzymes, resulting in the increased acetylation of histones, thereby affecting gene expression. There is strong evidence to suggest that HDACis can be utilised in stem cell therapies and tissue engineering, potentially providing novel tools to control stem cell fate. This review introduces the structure/function of HDAC enzymes and their links to different tissue types (specifically bone, cardiac, neural tissues), including the history, current status and future perspectives of using HDACis for stem cell research and tissue engineering, with particular attention paid to how different HDAC isoforms may be integral to this field.
Acetylation ; drug effects ; Histone Deacetylase Inhibitors ; pharmacology ; Histone Deacetylases ; metabolism ; Histones ; isolation & purification ; metabolism ; Humans ; Tissue Engineering

OBJECTIVETo investigate the effect of phenyl-hexyl isothiocyanate (PHI) on acetylation and methylation of histone in acute lymphoblastic leukemia cell line Molt4.

METHODSThe inhibition of cell proliferation was observed by MTT method and clone suppression test. Apoptosis and cell cycle arrest were measured by flow cytometry. The alterations in histone acetyltransferase and acetylation and methylation of histones were detected by Western blot.

RESULTSPHI could up-regulate the expression of acetyltransferase (P300/CBP), markedly induced the accumulation of acetylated histone H3, H4 and methylated histone H3 lysine 4 (H3K4), and inhibited methylation on lysine 9 of H3 (H3K9). The epigenetic regulation resulted in cell cycle arrest at G0/G1 phase, and induction of apoptosis.

CONCLUSIONSPHI can modulate both histone methylation and acetylation. It may serve as a histone deacetylase inhibitor, and might be a potential novel anti-leukemia agent.

Acetylation ; drug effects ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Epigenesis, Genetic ; Histone Deacetylases ; metabolism ; Histones ; metabolism ; Humans ; Isothiocyanates ; pharmacology ; Methylation ; drug effects

OBJECTIVETo characterize the DNA damage property represented by the distinct whole nucleus stain pattern of gammaH2AX induced by N-methyl-No-nitro-N-nitrosoguanidine (MNNG).

METHODSMNNG-induced gammaH2AX foci formation in human amnion FL cells was observed by immunofluorescent microscopy. DNA double-stranded breaks (DSBs) were detected by neutral comet assay. General DNA damages were detected by alkaline comet assay.

RESULTA distinct whole nucleus stain pattern of gammaH2AX was induced by high concentration MNNG (10 mg/L). 1 mg/L MNNG also induced this type of stain pattern in a small fraction of cells, although the effect was transient. Neutral comet assay did not detect any significant DSBs formation in this type of cells, while alkaline comet assay revealed the presence of DNA damage.

CONCLUSIONAlthough normal gammaH2AX foci were regarded as a biomarker for DSBs, the whole nucleus stain pattern might represent DNA damage other than DSBs.

Amnion ; cytology ; Cell Nucleus ; drug effects ; metabolism ; Comet Assay ; DNA Breaks, Double-Stranded ; drug effects ; DNA Damage ; Histones ; analysis ; Humans ; Methylnitronitrosoguanidine ; pharmacology ; Microscopy, Fluorescence ; Phosphoproteins ; analysis

OBJECTIVETo investigate the effects of curcumin on the acetylation of histone H3, P53 and the proliferation of NB4 cells.

METHODSThe total protein was extracted from NB4 cells treated without or with different concentrations of curcumin ( 50, 25, 12.5, 6.25 and 3.125 micromol/L) for different time (0, 4, 8, 12, 24 h). Western blot analysis was performed to determine the levels of acetylated histone H3, P53 and acetylated P53. MTT assay was performed to examine the growth inhibition effect of curcumin on NB4 cells.

RESULTSCurcumin could inhibit the proliferation of NB4 cells in a time- and dose- dependent manner, with the IC50 at 24 h and 36 h of 40 micromol/L and 25 micromol/L, respectively. The levels of histone H3 acetylation, P53 expression and P53 acetylation were increased obviously.

CONCLUSIONCurcumin functions as a deacetylase inhibitor,which could increase the level of acetylated histone H3, enhance the expression and activity of tumor suppressor P53, and inhibit the proliferation of NB4 cells.

Acetylation ; drug effects ; Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Curcumin ; pharmacology ; Histones ; metabolism ; Humans ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo study the role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) in silica-induced DNA double-strand break repair in human embryo lung fibroblasts (HELF).

METHODSTwo stable transfectants, HELF transfected with DNA-PKcs siRNA (HELF-PKcs) and with negative control siRNA (HELF-NC), were established. HELF cells were treated with 0, 25, 50, 100, 200, 300 and 400 microg/ml silica for 12 h and with 200 microg/ml silica for different times (0, 1, 2, 6, 12 and 24 h). HELF-PKcs and HELF-NC were treated with 200 microg/ml silica for 0, 12 and 24 h. The expression levels of DNA-PKcs and phosphor-H2AX (H2AX) were determined by Western blot. DNA double strand breaks were measured by neutral comet assay.

RESULTSAfter treatment with different doses of silica for 12 h, the levels of H2AX and the percentages of tail DNA increased in concentration-dependent manner. After treatment with 200 microg/ml silica for different times, the levels of H2AX increased in a time-dependent manner. The percentages of tail DNA increased significantly at 6 h, and reaching maximum at 12 h and then decreasing at 24 h. The expression level of DNA-PKcs was suppressed in HELF-PKcs. After treatment with silica at 12 h, the level of H2AX was lower in HELF-PKcs than in HELF-NC, and the percentages of tail DNA increased obviously in both HELF-PKcs and HELF-NC compared with non-treated cells, but no significant difference was found in the percentages of tail DNA between them. The percentages of tail DNA decreased markedly in silica-treated HELF-NC and was significantly lower than in HELF-PKcs at 24 h (P < 0.05).

CONCLUSIONSilica can induce DNA double strand breaks in human embryo lung fibroblasts. DNA-PKcs might play a major role in silica-induced DNA double strand break repair. Silica-induced histone H2AX phosphorylation was dependent on DNA-PKcs.

Cell Line ; DNA Breaks, Double-Stranded ; drug effects ; DNA Repair ; DNA-Activated Protein Kinase ; genetics ; metabolism ; Fibroblasts ; drug effects ; physiology ; Histones ; metabolism ; Humans ; Phosphorylation ; Silicon Dioxide ; pharmacology ; Transfection

Methylation events play a critical role in various cellular processes including regulation of gene transcription and proliferation. We observed that methyltransferase activity underwent time-dependent changes in the cytosol of the rat hepatocytes upon partial hepatectomy. However, any change in the methylation of nuclear proteins is not clear during hepatocyte proliferation. The nuclear fraction possesses basal level of methyltransferase to catalyze methylation of several proteins ranging from 7 to 70 kD prior to any hepatecmony. The specific p16 (16 kD) band was transiently and heavily methylated post 1 day hepatectomy, and then became non- detectable, but not in the control liver. Methylation of p16 band was completely inhibited by exogenously added histones, particularly 2AS, 1, 2A and 2B subtypes. The methylated p16 protein remains stable in either acid or alkali- induced demethylation conditions, indicating that methylation is not likely to occur on isoaspartyl or C-terminal cysteinyl residues. Exogenous addition of non-hydrolyzable GTP caused a dose- dependent suppression of a p16 methylation suggesting that G-proteins might play a role as an endogenous methylation inhibitor in vivo. Taken together, we have identified the proliferation event associated-methylation of the nuclear p16 protein in the hepatocytes undergoing liver regeneration.
Alkalies/pharmacology ; Animals ; Cell Proliferation ; Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology ; Hepatectomy ; Hepatocytes/drug effects/*metabolism ; Histones/pharmacology ; Liver Regeneration/drug effects/*physiology ; Methylation/drug effects ; Nuclear Proteins/*metabolism ; Rats ; Research Support, Non-U.S. Gov't ; Sodium Chloride/pharmacology