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PubMed1996

Sodium butyrate induces tyrosine phosphorylation and activation of MAP kinase (ERK-1) in human K562 cells.

Butyrate is a naturally occurring 4-carbon fatty acid. Biologically, butyrate has been shown to affect the morphology and growth rate of mammalian cells, as well as induce gene expression. Moreover, butyrate has been proven to serve as an anticancer agent, which unlike others (methotrexate and hydroxyurea), is a nontoxic, safe alternative to cancer treatment. It also induces erythroid differentiation in K562 cells. However, its mechanism of action has yet to be determined. In this study we investigated the effects of sodium butyrate (NaB) on tyrosine phosphorylation in K562 erythroleukemic cells. We demonstrate that NaB induces both dose and time-dependent tyrosine phosphorylation of several proteins, the effects of which were blocked by the tyrosine kinase inhibitor genistein. Furthermore, NaB induces tyrosine phosphorylation and rapid activation of MAP kinase (ERK-1). These findings provide the first evidence that the signal transduction mechanism of NaB involves rapid tyrosine phosphorylation and activation of MAP kinase.

Butyrates↗
PubMed1996

Regulation of neutrophil apoptosis by sodium butyrate.

Neutrophils have a very short half life because they constitutively undergo apoptosis. Granulocyte-macrophage colony-stimulating factor (GM-CSF) can delay apoptosis, but this agent also primes functions such as the respiratory burst and receptor upregulation. Here, we show that sodium butyrate, which has been shown to increase gene expression and differentiation in a variety of cell types, is more effective than GM-CSF in delaying neutrophil apoptosis. Thus, sodium butyrate preserves cell morphology and function, and butyrate-treated cells express high levels of CD16 after overnight culture. However, neither GM-CSF nor sodium butyrate appear to affect mRNA levels for CD16.

Apoptosis↗
PubMed1996

Disruption of cell-cell adhesion in the presence of sodium butyrate activates expression of the 92 kDa type IV collagenase in MDCK cells.

We have investigated the effects of altered cell shape on the regulation of the 92 kDa type IV collagenase. In MDCK cells, anti-E-cadherin antibodies alter cell shape by disrupting normal cell-cell contacts, while sodium butyrate causes a marked flattening and spreading of cells. The disruption of cell-cell contacts led to a faint expression of the 92 kDa collagenase. This effect was enhanced by sodium butyrate, which by itself did not induce collagenase expression. In contrast, stromelysin expression was not regulated in these conditions. Although mRNA expression was enhanced, the secreted collagenase activity was not altered in these conditions in either cell line. Examination of cytoskeletal and extracellular matrix proteins and cell-cell and cell-matrix adhesion proteins by immunofluorescence and Western blot revealed a disruption of the actin network, tight junctions, and fibronectin deposition by anti E-cadherin antibodies, and alterations in actin, cytokeratin 8, cytokeratin 14, laminin and beta 1 integrin induced by sodium butyrate. Thus, the induction of collagenase expression in epithelial cells by disrupted cell-cell adhesion and sodium butyrate is associated with changes in cell shape and structure.

Animals↗
PubMed1993

Sodium butyrate treatment of cells latently infected with HIV-1 results in the expression of unspliced viral RNA.

To investigate potential mechanisms for HIV-1 proviral latency, we generated a set of chronically HIV-1 infected and stably long terminal repeat-chloramphenicol acetyl transferase (LTR-CAT)-transfected TE671/RD cells, and studied both their virus production and LTR-driven reporter gene expression. Established tissue culture models of retroviral latency in lymphoid and monocytoid cell lines have demonstrated that the induction of virus production is associated with a shift in HIV-1-specific mRNA from a predominance of singly and multiply spliced mRNA's to the production of full-length HIV-1 RNA. We found a similar pattern in TE671/RD cells, but in contrast to U1 and ACH2 cells, could not induce viral replication by exposure to phorbol myristate acetate (PMA) alone. We demonstrated instead that production of full-length viral RNA, viral replication, and LTR-driven CAT expression could be induced by exposure to sodium butyrate. The most proximate effect of sodium butyrate is inhibition of cellular histone deacetylase(s) which results in disruption of nucleosomes relieving one level of restriction to gene expression. Consistent with this mechanism of action, we further found that sodium butyrate's effects: (i) act synergistically with PMA and TNF-alpha; (ii) are independent of protein synthesis; (iii) do not affect the constitutively expressed creatine phosphokinase gene; (iv) do not map to a discrete sequence motif in the viral LTR; and (v) are not blocked by N-acetyl cysteine but (vi) are blocked by novobiocin, an inhibitor of cellular topoisomerase II. These data show that a similar pattern of restricted viral RNA expression exists in this nonlymphoid cellular model of HIV-1 latency. In contrast however, these results suggest that in these cells there is an additional block to viral gene expression, which is overcome with sodium butyrate. These results are discussed in the context of histone-mediated repression of HIV-1 gene expression.

Acetylcysteine↗
PubMed1984

Effects of n-butyrate and phorbol ester (TPA) on induction of Epstein-Barr virus antigens and cell differentiation.

N-Butyrate, an effective inducer of synthesis of Epstein-Barr virus (EBV) antigens in virus-producer P3HR-1 cells, has recently been shown (2) to induce morphological differentiation towards plasma cell in nonproducer Raji cells. The effects of n-butyrate and 12-O-tetradecanoylphorbol-13-acetate (TPA) on both EBV-antigen induction and cell differentiation in two virus-nonproducer lymphoblastoid cell lines, Raji and NC37, were now studied. The following observations were made (1). On its own either drug induced 1-2 per cent of cells to EBV-early-antigen positivity in both lines; their mixture induced 35 and 15 per cent positive cells in Raji and NC37 respectively (2). In Raji, n-butyrate induced about 80 per cent of cells to differentiate to plasmablast or plasma cell morphology, whereas TPA only induced the early stages of differentiation in 8 per cent of cells; a mixture of both inducers produced a similar effect as TPA alone. The addition of TPA alone or butyrate-TPA mixture led to some cellular alterations resembling virus-specific changes in virus-producer cell lines. In NC37, either drug alone or their mixture drove 13 per cent of cells to differentiate into plasmablasts or earlier stages of differentiation. In the presence of TPA protrusions and "loops" were seen on cell surfaces. Evidently, the stage of differentiation at which B-lymphoblastoid cell lines have been arrested can be changed in vitro. However, cell-line dependent and inducer-dependent differences in the differentiation response were apparent.

Antigens, Viral↗
PubMed1984

Effect of sodium butyrate on human breast carcinoma (MCF-7) cellular proliferation, morphology, and CEA production.

Sodium butyrate is a potent inducer of leukemic cell differentiation. This agent also affects epithelial cell proliferation and gene expression. The present study demonstrates that sodium butyrate slows proliferation and induces morphologic changes in human MCF-7 breast carcinoma cells. The results also demonstrate that butyrate-treated MCF-7 cells have enhanced expression of carcinoembryonic antigen. These effects are related to butyrate concentration and duration of exposure. The present findings may provide a model for studying maturation of human breast cancer cells.

Breast Neoplasms↗
PubMed1984

Associated effects of sodium butyrate on histone acetylation and estrogen receptor in the human breast cancer cell line MCF-7.

Sodium butyrate at a concentration of 5mM causes significant hyperacetylation of the core histones in the human breast cancer cell line MCF-7. Histone hyperacetylation was achieved in rapidly-growing cells at 40% confluency after 24 hours in 5mM sodium butyrate. More nearly confluent cells did not reach as high a level of histone hyperacetylation. Upon assaying the estrogen receptors, both cytosolic and KCl-extractable nuclear, we found that butyrate treatment had lowered the estrogen receptor levels in both compartments. To our knowledge this is the first report of an effect of sodium butyrate on estrogen receptor levels.

Acetylation↗
PubMed1984

Effect of sodium butyrate on induction of ornithine decarboxylase activity in phytohemagglutinin-stimulated lymphocytes.

Effect of sodium butyrate on DNA synthesis and the induction of ornithine decarboxylase (EC 4.1.1.17), a rate-limiting enzyme of polyamine biosynthesis, was studied in phytohemagglutinin (PHA)-stimulated bovine lymphocytes. Millimolar concentrations of butyrate completely inhibited the incorporation of [3H]thymidine into the acid-insoluble fraction and reversibly suppressed the induction of ornithine decarboxylase. Other short-chain fatty acids were much less active than butyrate. These results suggest that the suppression of ornithine decarboxylase activity may be one of the reasons for the inhibition of DNA synthesis with butyrate in bovine lymphocytes, because our previous experimental results have shown that the induction of ornithine decarboxylase closely correlates with the DNA synthesis in growth-stimulated cells.

Animals↗
PubMed1988

Butyrate effect on nuclear proteins of two Chinese hamster cell lines.

The effect of sodium butyrate on the nuclear proteins of two Chinese hamster cell lines (V79 and CHO) was studied. Butyrate treatment induces hyperacetylation of core histones in both cell lines, while H1 histone shows a different behavior. In CHO cells H1 is dephosphorylated following butyrate incubation; V79 do not show any change of H1 subtypes. It seems that H1 response to butyrate treatment is cell type dependent. Using silver staining a group of proteins that could be present in vivo in the nucleo-protein complex was also detected.

Acetylation↗
PubMed1991

Reversible effects of sodium butyrate on the differentiation of F9 embryonal carcinoma cells.

We have studied effects of sodium butyrate on embryonal carcinoma F9 cell differentiation. In the presence of sodium butyrate, F9 cells underwent rapid and drastic morphological changes and expressed marked increases in mRNA levels of various differentiation markers. When sodium butyrate was removed from the cultures, all the examined phenotypes of F9 cell differentiation rapidly reverted to the characteristics of undifferentiated stem cells. However, under the same conditions, when cycloheximide or actinomycin D was added to the cultures, such phenotypic reversion was not observed, but high mRNA levels of the differentiation markers as well as altered cell morphology were retained. These results indicated that the effects of sodium butyrate on induction of teratocarcinoma cell differentiation were reversible and that de novo syntheses of some mRNA(s) and protein(s) were necessary for the reversion of differentiated cells to stem cells.

Animals↗
PubMed1995

Sodium butyrate inhibits expression of urokinase and its receptor mRNAs at both transcription and post-transcription levels in colon cancer cells.

The effects of butyrate on the modulation of urokinase plasminogen activator (uPA) and its receptor (uPAR) mRNAs were studied. While both mRNA levels were increased after stimulation by tumor necrosis factor alpha (TNF alpha), phorbol ester (PMA) and cycloheximide, they were inhibited by butyrate at 2.5 to 25 mM. Nuclear run-on transcription assays indicated that uPA mRNA was modulated by butyrate at the transcriptional level but the uPAR gene was regulated at both transcriptional and post-transcriptional levels in the presence or absence of TNF alpha. In the presence of PMA, however, butyrate acts at the post-transcriptional level on both genes.

Butyrates↗
PubMed1993

Effects of short chain fatty acid, sodium butyrate, on osteoblastic cells and osteoclastic cells.

1. Sodium butyrate increased alkaline phosphatase (ALP) activity of cloned osteoblastic cell line MC3T3-E1 by the stimulation of de novo enzyme synthesis. 2. Sodium butyrate did not affect mature osteoblastic cells but affected preosteoblastic cells. 3. Sodium butyrate decreased tartrate resistant acid phosphatase (TRACP)-positive multinucleated cells (MNC) formation from bone marrow cells. This related to the cytotoxicity of sodium butyrate on bone marrow cells.

Acid Phosphatase↗
PubMed1986

Butyrate-induced reversal of herpes simplex virus restriction in neuroblastoma cells.

The synthesis of herpes simplex virus (HSV) in mouse neuroblastoma cells (NB, clone 41A3) is restricted. There was a disappearance of infectious virus upon serial passage of infected cells. NB cells treated with sodium-n-butyrate for 24 hr before infection synthesized 200-2000 times more HSV than untreated cells. Infectious center assays demonstrated that the number of cells capable of producing HSV was increased as a result of butyrate pretreatment. Although host protein synthesis was inhibited by HSV infection, viral-induced protein and DNA syntheses were not detected in the absence of butyrate. Cycloheximide blocked the induction of permissiveness by butyrate suggesting that a protein(s) was responsible for allowing HSV synthesis in NB cells. Regulatable host factors involved in HSV replication in neural cells can be studied in the system described.

Animals↗
PubMed1983

Modulation of in vitro myogenesis by submillimolar concentrations of sodium butyrate.

The effects of submillimolar concentrations of sodium butyrate on the differentiation of cultured chick myoblasts have been studied. The continuous presence of 0.5 mM butyrate inhibited myoblast fusion, creatine kinase (CK) isozyme transition, and synthesis of total RNA and protein until the 4th day of myogenesis, after which the fusion index reached control values and total CK activity was elevated. The latter continued to exhibit daily increases over control levels, largely reflecting activity of the MM-CK muscle-specific isozyme which increased to twice the control level by the 8th day. Similar but less striking patterns of early inhibition followed by stimulation were observed for total protein content and synthesis of total protein and RNA. On the other hand, DNA content was slightly but significantly depressed in treated cultures at all times. Butyrate treatment did not reverse 5'-bromodeoxyuridine (BUdR) inhibition of MM-CK differentiation. It was also noted that continuous treatment with 0.5 mM butyrate prevented the unexplained sporadic deterioration of myotubes sometimes observed at the 4th day.

Animals↗
PubMed1990

Dynamic histone acetylation in alfalfa cells. Butyrate interference with acetate labeling.

Dynamic histone acetylation of alfalfa (Medicago sativa) was studied in suspension cultures by short-term labeling with radioactive acetate. The relative labeling rates for the acetylated histones were in order of decreasing incorporation; H3.2 greater than H3.1 greater than H4 greater than H2B.1 greater than H2A.3. Histone H3 showed at least seven sites of acetylation, histone H2B.1 had six sites and histone H4 had five sites. Low numbers of acetylation sites were observed for histone H2B.2 and all histone H2A variants. The mass ratio, steady state acetylation and dynamic acetylation between major variant H3.1 and minor variant H3.2 were approx. 2:1, 1:2 and 2:5, respectively. Treatment of alfalfa cells with 50 mM n-butyrate did not lead to histone hyperacetylation, but instead interfered with histone acetylation labeling by acetate. The extent of apparent inhibition increased with time and concentration of butyrate. It is likely that the conversion of butyrate to acetylCoA results in dilution of the specific radioactivity of [3H]acetate in the acetylCoA pool thereby inhibiting the labeling reaction. This interpretation is supported by 14C-labeling of alfalfa acetylated histones by [1-14C]butyrate.

Acetates↗
PubMed1987

Induction of cellular transglutaminase biosynthesis by sodium butyrate.

Cellular transglutaminase activity was induced in simian virus-transformed human embryonic lung fibroblasts (WI-38 VA13A) by sodium butyrate. The level of enzyme activity approached a maximum by 6 days; 9-11-fold higher in the presence of sodium butyrate (1 mM) than in its absence. The observed increases in cellular transglutaminase activity could be entirely accounted for by equivalent increases in the levels of enzyme protein measured by inhibition enzyme-linked immunosorbent assay. Sodium butyrate also increased the rate of enzyme synthesis, but had no effect on the rate of cellular transglutaminase degradation. The increase in the rate of enzyme synthesis was matched by an increased level of translatable transglutaminase mRNA as measured in a cell-free translation system. Our results suggest that sodium butyrate regulates cellular transglutaminase at the pretranslational level.

Antibodies, Monoclonal↗
PubMed1984

Ultrastructural studies on human lymphoblastoid cells treated with n-butyrate and 12-O-tetradecanoylphorbol-13-acetate.

The effects of n-butyrate and/or 12-O-tetradecanoylphorbol-13-acetate (TPA) on Raji and P3HR-1 cells were examined using electron microscopy. n-Butyrate treatment caused a decrease in the number and elongation of surface microvilli. In addition, well-developed rough endoplasmic reticulum and a marked decrease in condensed chromatin clumps were observed in the nucleus. The filamentous structures and nuclear membrane-like structures, which were not reported previously, appeared occasionally in the nucleus. On the other hand, in the cells treated with TPA no marked morphological changes were observed except the higher cytoplasmic:nuclear ratio. n-Butyrate-induced morphological changes were not inhibited when combined with TPA or retinoic acid. Electron microscopic studies showed remarkable differences in morphological change in these cells treated with n-butyrate and/or TPA.

Antigens, Viral↗
PubMed1990

Effects of intravenous injection of butyrate, valerate and their isomers on endocrine pancreatic responses in conscious sheep (Ovis aries).

1. The effects of intravenous injection of n-butyrate, iso-butyrate, n-valerate and iso-valerate on insulin and glucagon secretion was examined in conscious sheep. 2. Each sodium salt of the short chain fatty acids increased plasma insulin and glucagon concentrations in a dose-dependent manner (312-1250 mumol/kg body wt). 3. Both butyrate and valerate isomers with branched carbon chains had larger insulin releasing activity than isomers with straight carbon chains. 4. The glucagon responses to butyrate or valerate did not differ between the isomers with straight carbon chains and those with branched carbon chains. 5. Our results suggest that the receptive mechanism to short chain fatty acids, which may involve the nervous system, differs between the A cell and the B cell in sheep in vivo.

Animals↗