ARNTL Transcription Factors ; deficiency ; metabolism ; Animals ; Cyclic AMP ; metabolism ; Gluconeogenesis ; Glucose ; biosynthesis ; HEK293 Cells ; Histone Deacetylases ; metabolism ; Humans ; Liver ; metabolism ; Mice ; Mice, Knockout

Animals ; Embryonic Stem Cells ; virology ; Gene Expression Regulation, Enzymologic ; Histone Deacetylase 6 ; Histone Deacetylases ; biosynthesis ; genetics ; Infection ; genetics ; pathology ; virology ; Mice ; Mice, Knockout

Viruses initiate a number of cellular stress responses and modulate gene regulation and compartmentalization of RNA upon infection to be successful parasites. Virus infections may induce or impair stress granule (SG) formation to maximize replication efficiency. SGs and processing bodies (PBs) are the RNA granules, which contain translationally inactive pool of transcripts as the mRNA silencing foci. PBs and SGs, the highly conserved macromolecular aggregates, can release mRNAs to allow their translations. Unlike constitutively existing PBs that can respond to stimuli and affect mRNA translation and decay, SGs are specifically induced upon cellular stress and can triggers a global translational silencing by several pathways, including phosphorylation of the key translation initiation factor eIF2alpha, tRNA cleavage, and sequestration of cellular components and so on. The dynamics of PBs and SGs are regulated by several signaling pathways, including histone deacetylase 6, and depend on microfilaments and microtubules, and the cognate molecular motors myosin, dynein, and kinesin. SGs share features with aggresomes and related aggregates of unfolded proteins and may play a role in the pathology. The recent advances in understanding the relationship between viruses and mRNA stress granules are summarized.
Actin Cytoskeleton ; Dyneins ; Histone Deacetylases ; Kinesin ; Microtubules ; Myosins ; Parasites ; Peptide Initiation Factors ; Phosphorylation ; Protein Biosynthesis ; Proteins ; RNA ; RNA, Messenger ; RNA, Transfer ; Translations ; Viruses

OBJECTIVETo express and purify the fusion proteins of glutathione S-transferase (GST)-N-terminal of histone deacetylase4 (HDAC4-N') (1-1952 bp) and GST- C-terminal of HDAC4 (HDAC4-C') (1708-3255 bp) in E.coli.

METHODSThe DNA fragments (HDAC4-N' and HDAC4-C') amplified by PCR were ligated into GST fusion vector (pGEX-6P-1) to construct the recombinant plasmids. After identification with restriction digestion and DNA sequencing, the recombinant plasmids were transformed into E.coli BL21 and induced by IPTG for their expression. After identification by SDS-PAGE and Western blotting, the target proteins were purified by glutathione sepharose 4B.

RESULTSThe results of restriction digestion and DNA sequencing confirmed successful construction of the recombinant plasmids. The relative molecular masses of the fusion proteins were approximately 110500 and 93080 as shown by SDS-PAGE. Western blotting demonstrated that the fusion proteins could be recognized by the specific anti-HDAC4 antibody.

CONCLUSIONWe have successfully constructed the recombinant expression vectors of pGEX-6P-1/HDAC4-N' and pGEX-6P-1/HDAC4-C' and induced the expression of the fusion proteins, which may facilitate functional studies of HDAC4 with other proteins.

Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Glutathione Transferase ; biosynthesis ; genetics ; Histone Deacetylases ; biosynthesis ; genetics ; Humans ; Peptide Fragments ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; isolation & purification ; Repressor Proteins ; biosynthesis ; genetics

We previously reported that trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, induced DLC-1 mRNA expression and accumulated acetylated histones H3 and H4 associated with the DLC-1 promoter in DLC-1 non-expressing gastric cancer cells. In this study, we demonstrated the molecular mechanisms by which TSA induced the DLC-1 gene expression. Treatment of the gastric cancer cells with TSA activates the DLC-1 promoter activity through Sp1 sites located at -219 and -174 relative to the transcription start site. Electrophoretic mobility-shift assay (EMSA) revealed that Sp1 and Sp3 specifically interact with these Sp1 sites and showed that TSA did not change their binding activities. The ectopic expression of Sp1, but not Sp3, enhances the DLC-1 promoter responsiveness by TSA. Furthermore, the TSA-induced DLC-1 promoter activity was increased by p300 expression and reduced by knockdown of p300. These results demonstrated the requirement of specific Sp1 sites and dependence of Sp1 and p300 for TSA-mediated activation of DLC-1 promoter.
Cell Line, Tumor ; Electrophoretic Mobility Shift Assay ; Histone Deacetylases/*antagonists & inhibitors/metabolism ; Humans ; Hydroxamic Acids/*pharmacology ; Promoter Regions, Genetic ; Sp1 Transcription Factor/genetics/*metabolism ; Sp3 Transcription Factor/genetics/metabolism ; Stomach Neoplasms/*metabolism ; Transcription, Genetic ; Tumor Suppressor Proteins/*biosynthesis/genetics ; p300-CBP Transcription Factors/genetics/metabolism

AMP-activated protein kinase, AMPK, is responsible for regulation of exercise-induced GLUT4 gene expression in skeletal muscle. But the molecular mechanisms for this regulation and key protein in this signaling pathway are obscure. There has been growing recognition that histone acetylation probably represents a central mechanism for regulation of gene transcription, and recent studies showed that numerous gene expressions are regulated by nucleosomal histone acetylation, which is modulated through histone acetyltransferases (HATs) and histone deacetylases (HDACs). So we have a hypothesis that the AMPK regulates GLUT4 gene through recruiting HDACs. Skeletal muscle cells cultured with normal (5 mmol/L) and high (20 mmol/L) glucose concentration were incubated with AICAR, and then total and nuclear AMPKalpha2, HDAC5 protein and GLUT4 mRNA were measured. The results show that the AICAR activated AMPKalpha2, reduced nuclear HDAC5,and increased GLUT4 mRNA in skeletal muscle cells; in contrast, the effect evoked by AICAR was blunted in cultured skeletal muscle cells with high glucose. Therefore, the changes of GLUT4 gene expression under different glucose concentration are closely related to the changes of AMPKalpha2 and HDAC5 protein in skeletal muscle cells. This result demonstrates that HDAC5 plays an important role in regulating GLUT4 gene transcription by AMPK signaling pathway skeletal muscle cells.
AMP-Activated Protein Kinases ; metabolism ; Cells, Cultured ; Glucose Transporter Type 4 ; biosynthesis ; genetics ; Histone Deacetylases ; metabolism ; Humans ; Muscle, Skeletal ; cytology ; enzymology ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Signal Transduction ; Transcription, Genetic

OBJECTIVETo construct an expression vector of siRNA targeting human MTA1 gene and observe its gene-silencing effect in esophageal carcinoma cells.

METHODSThe siRNA sequences targeting MTA1 gene were designed and synthesized with two complementary oligonucleotide strands. The oligonucleotide strands were annealed and recombined into pRNAT-U6.2 vector, which was identified by sequencing following transformation and amplification. The siRNA expression vector pRNAT-U6.2-MTA1 was transfected into human esophageal carcinoma EC9706 cells via liposome. RT-PCR and Western blotting were used to detect expression levels of MTA1 mRNA and protein in the transfected EC9706 cells, respectively.

RESULTSThe double-stranded oligonucleotide fragments of the siRNA targeting MTA1 gene were cloned into pRNAT-U6.2 vector, which was validated by sequence analysis. RT-PCR and Western blotting indicated that MTA1 mRNA and protein expressions were significantly decreased in the transfected cells, especially in those transfected with the siRNA targeting the sequence of GACCCTGCTGGCAGATAAA (481-499), which induced almost complete silencing of MTA1 protein expression.

CONCLUSIONThe siRNA expression vector pRNAT-U6.2-MTA1 for silencing MTA1 gene expression in the esophageal carcinoma cells has been successfully constructed, which may facilitate further study for decreasing the invasive and metastatic potentials of malignant tumors by MTA1 gene silencing.

Base Sequence ; Blotting, Western ; Cell Line, Tumor ; Cloning, Molecular ; Esophageal Neoplasms ; genetics ; metabolism ; pathology ; Genetic Vectors ; genetics ; Histone Deacetylases ; biosynthesis ; genetics ; Humans ; Molecular Sequence Data ; RNA Interference ; RNA, Messenger ; biosynthesis ; genetics ; RNA, Small Interfering ; genetics ; Repressor Proteins ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

OBJECTIVETo investigate the effect of curcumin (Cur) on histone deacetylase (HDAC1) and P21(WAF1/CIP1), a cyclin dependent kinase inhibitor, in HepG2 cells for exploring the mechanism of Cur in anti-cancer.

METHODThe HDAC1, P21(WAF1/CIP1) proteins and P21(WAF1/CIP1) mRNA were extracted from human hepatoma cells treated with or without Cur of different concentrations at different time points. Western blot analysis was performed to determine the levels of HDAC1 and P21(WAF1/CIP1) proteins, respectively. RT-PCR was performed to detect the level of P21(WAF1/CIP1) mRNA.

RESULTThe IC50 of concentration treated by Cur was 25 micromol x L(1) on HepG2 cell. The level of HDAC1 was obviously inhibited by Cur, and decreased at 4 hours at IC, and lasted for 48 h in a time-dependent manner. The inhibition of HDAC1 was significant at the Cur concentration of 12.5 micromol x L(-1) but there was no difference between 50 and 100 micromol x L(-1). The levels of P21(WAF1/CIP1) mRNA and protein were up-regulated by Cur in dose and time-dependent manner, and the change of mRNA and protein was detected at 8 hours and lasted for 48 hours.

CONCLUSIONCur can inhibit the level of HDAC1 and enhance the expression of P21(WAF1/CIP1) protein and mRNA, and the results suggest that inhibiting HDAC1 and increasing P21(WAF1/CIP1) may be one of the possible mechanisms of anti-cancer by Cur.

Blotting, Western ; Carcinoma, Hepatocellular ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Curcuma ; chemistry ; Curcumin ; administration & dosage ; isolation & purification ; pharmacology ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Neoplastic ; drug effects ; Histone Deacetylase Inhibitors ; Histone Deacetylases ; metabolism ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; Plants, Medicinal ; chemistry ; RNA, Messenger ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors

The purpose of this study was to investigate the effect of curcumin on proliferation of B-NHL Raji cell line and explore the relationship between this effect and regulatory expression of p300 and HDAC1 transcription. The in vitro cultured Raji cells were treated with curcumin at various concentrations (6.25-50 micromol/L) and at different time points (0, 6, 12, 24 and 48 hours), the inhibitory ratio of cell growth was measured by MTT assay, the cell apoptosis rate was detected by flow cytometry with Annexin V-FITC/PI double staining, the changes of p300 and HDAC1 mRNA expression and protein level in Raji cells were determined by RT-PCR and Western blot. The results showed that the curcumin could inhibit Raji cell proliferation in significant time-and concentration-dependent manners, IC50 at 24 hours was 25 micromol/L; the curcumin could induce apoptosis of Raji cells in concentration-dependent manner, apoptosis rate was 14.38%-61.18%. The curcumin significantly inhibited activity and expression of p300 and HDAC1. At IC50 concentration, expression of p300 and HDAC1 mRNA and protein level decreased with time-dependent manner, difference between tested and control groups was significant (P < 0.05). It is concluded that the curcumin can inhibit proliferation of B-NHL Raji cells and promote apoptosis of those cells. Curcumin can inhibit the activity and expression of the transcriptional co-activator p300 and HDAC1, which may be involved in its pharmacological mechanisms on B lymphoma cells.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Curcumin ; pharmacology ; Dose-Response Relationship, Drug ; E1A-Associated p300 Protein ; biosynthesis ; genetics ; Histone Deacetylase 1 ; Histone Deacetylases ; biosynthesis ; genetics ; Humans ; Lymphoma, B-Cell ; metabolism ; pathology ; RNA, Messenger ; biosynthesis ; genetics ; Tumor Cells, Cultured

To compare the expression level of metastasis associated-1 (MTA1) gene in high and low metastatic human osteosarcoma cell lines and examine the relationship of MTA1 expression and the metastasis potentiality of osteosarcoma cells, the expression of MTA1 in MG-63 osteosarcoma cell lines with high and low metastasis potential was detected by semiquantitative TR-PCR. Boyden chamber invasion assay was used to evaluate the invasive capacity in vitro in two osteosarcoma cell lines. The low metastasis MG-63 cells were transfected with MTA1 full-length cDNA expression plasmid by lipofectamine and the changes of MTA1 expression and in vitro invasion potential were examined after the transfection. Our results showed that MG63 cell line with high metastasis potential expressed significantly higher MTA1 than that of MG63 cells with low metastasis as reavealed by RT-PCR. The invasion potential of low metastasis MG63 cell line was increased after MTA1 gene transfection. It is concluded that there may be a relationship between MTA 1 and invasive potentiality of human osteosarcoma cells, and the mechanism of MTA1 in osteosarcoma metastasis and its possible role in associated gene therapy deserve further study.
Bone Neoplasms/*metabolism ; Bone Neoplasms/pathology ; Gene Expression Regulation, Neoplastic ; Histone Deacetylases/*biosynthesis ; Histone Deacetylases/genetics ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Osteosarcoma/*metabolism ; Osteosarcoma/pathology ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Repressor Proteins/*biosynthesis ; Repressor Proteins/genetics ; Tumor Cells, Cultured