A growing body of evidence suggests that p300 histone acetyltransferase plays important roles in cancer cell differentiation and proliferation. Here, we employed structure-based hierarchical virtual screening method to identify novel lead compounds of p300 histone acetyltransferase. From a screening library containing approximate 100 000 diverse druglike compounds, 33 compounds were chosen for experimental testing and one compound, 4-acetyl-2-methyl-N-morpholino-3,4-dihydro-2H-benzo[b][1, 4]thiazine-7-sulfonamide (17), showed as micromolar inhibitor. Based on its predicted binding pose, we investigated its binding characteristics by designing two series of structural modifications. The obtained structure-activity relationship results are consistent with the predicted binding model. We expect that the identified novel p300 histone acetyltransferase inhibitors will serve as starting points for further development of more potent and specific histone acetyltransferase inhibitors.
Drug Design ; Enzyme Inhibitors ; chemical synthesis ; chemistry ; Molecular Structure ; Morpholines ; chemical synthesis ; chemistry ; Structure-Activity Relationship ; Sulfonamides ; chemical synthesis ; chemistry ; p300-CBP Transcription Factors ; antagonists & inhibitors ; chemistry

Bacterial Proteins ; genetics ; CRISPR-Cas Systems ; genetics ; Endonucleases ; genetics ; Gene Editing ; HEK293 Cells ; Humans ; Transcriptional Activation ; genetics ; p300-CBP Transcription Factors ; genetics

OBJECTIVETo construct the Gcn5 shRNA plasmids and to explore the Gcn5 shRNA role in histone acetylation modification with the differentiation of stem cells.

METHODSSeven shRNA fragments were recombined into pGenesil-1 vector to form 7. Gcn5 shRNA constructions. The mesenchymal stem cells (MSCs) induced for two weeks with 5-aza were transfected by the plasmids with lipofectamine2000. Polyclonal antibodies labeled with TRITC were used to identify the acetylation in MSCs with or without Gcn5 shRNA constructions. The efficiencies of transfection and RNAi were calculated based on the ratio of GFP (green fluorescence)/DAPI (blue fluorescence) and TRITC (red fluorescence)/DAPI, respectively.

RESULTSSeven Gcn5 shRNA plasmids or constructions were identified by restriction endonucleases Pst I/Sal I and DNA sequencing. Acetylation block was observed after Gcn5 shRNA plasmids transfected into cells. Fluorescent intensity of TRITC in nucleuses were decreased remarkably, or even disappeared in MSCs. The efficiencies of transfection and RNAi were 93.7% and 46.6%, respectively.

CONCLUSIONThe Gcn5 shRNA plasmids constructed in the present study can decrease the histone acetylation during cell differentiation. It sets the basis for further exploring the role of acetylation in the regulation of cell differentiation.

Acetylation ; Animals ; Cell Cycle Proteins ; genetics ; Cell Differentiation ; drug effects ; physiology ; Histone Acetyltransferases ; genetics ; Histones ; metabolism ; Plasmids ; genetics ; RNA Interference ; RNA, Small Interfering ; pharmacology ; Rats ; Rats, Wistar ; Stem Cells ; cytology ; drug effects ; Transcription Factors ; genetics ; p300-CBP Transcription Factors

OBJECTIVETo observe the effects of moxibustion on factors related with apoptosis of myocardial cells after sports fatigue in mice as well as the relationship among histone acetyltransferases p300 (p300), CREB binding protein (CBP) and cell apoptosis to discuss the role of p300 and CBP in moxibustion against apoptosis of myocardial cells.

METHODSSixty clean-grade male Kunming mice were randomly divided into a control group, a sport group and a moxibustion group, 20 cases in each one. Mice in all group received identical feeding environment. Mice in the control group did not received sport nor moxibustion; mice in the sport group and moxibustion group received non-weight swimming training which lasted from 30 min per day to 90 min per day gradually for 21 days; 1 h after swimming training, mice in the moxibustion group received moxibustion with seed-sized moxa cone at "Zusanli" (ST 36) and "Guanyuan" (CV 4), 5 cones at each acupoint, once a day for 21 days. 24 h after the final swimming training, cardiac muscle tissue was collected to test factor associated suicide (Fas), B cell lymphoma/lewkmia-2 (Bcl-2) by immunohistochemical method and expression of p300 and CBP.

RESULTSCompared with the control group, the apoptosis rate of myocardial cells in the sport group was significantly increased (P<0.01), and apoptosis body with dense distribution and deep coloring can be seen in the field of microscope; the expression of Fas protein was significantly increased (P<0.01), and expression of Bcl-2, p300 and CBP was reduced (all P<0.01). The equally distributed apoptosis body with slight coloring was seen in the moxibustion group. Compared with the sport group, the apoptosis rate of myocardial cells in the moxibustion group was significantly reduced (P<0.05); the expression of Fas protein was significantly reduced (P<0.05), and expression of Bcl-2, p300 and CBP was increased (all P<0.05).

CONCLUSIONMoxibustion could promote the expression of p300 and CBP in myocardial cells after sports fatigue in mice to inhibit the starting of apoptotic process, therefore reducing the apoptosis of myocardial cells after heavy exercise and protecting heart function.

Acupuncture Points ; Animals ; Apoptosis ; Exercise ; Fatigue ; etiology ; metabolism ; physiopathology ; therapy ; Humans ; Male ; Mice ; Moxibustion ; Myocardium ; cytology ; metabolism ; Myocytes, Cardiac ; cytology ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; p300-CBP Transcription Factors ; metabolism

OBJECTIVETo study the effect of binding activities of the NH(2) terminus of E1A to the proteins regulating cell growth on ras-induced cell senescence and explore the mechanism of E1A-mediated escape from ras-induced senescence by E1A in human fibroblast.

METHODSIn primary human fibroblasts, the proteins regulating cell growth in association with E1A NH(2) terminus, including the Rb family proteins, p300/CBP, and p400, were inactivated or interfered. The effect of alterations in the binding activities of these proteins on cell senescence bypass mediated by E1A was evaluated by cell growth curve.

RESULTSThe Inactivation of Rb family proteins alone was not sufficient to rescue ras-induced cell senescence, whereas inactivation of both the Rb proteins and p300/CBP blocked ras-induced senescence of human fibroblasts.

CONCLUSIONRb and p300/CBP binding activities are both required for E1A to bypass ras-induced senescence in human fibroblasts.

Adenovirus E1A Proteins ; pharmacology ; Cellular Senescence ; drug effects ; Fibroblasts ; cytology ; Humans ; Primary Cell Culture ; Retinoblastoma Protein ; metabolism ; Skin ; cytology ; p300-CBP Transcription Factors ; metabolism ; ras Proteins ; antagonists & inhibitors ; pharmacology

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

OBJECTIVETo observe the inhibitory effect of cyclin-dependent kinase inhibitor p21 on regulation of survivin transcription in human liver cancer HepG cells, and explore the related mechanisms.

METHODSDoxorubicin (DOX) was used to treat HepG cells. Eukaryotic vector pEGFP-C2-p21 was transfected into HepG cells by lipofectamine and positive clones were screened out by G418. The mRNA expression of p21, p53 and survivin were detected by real-time fluorescent quantitative polymerase chain reaction (RQ-PCR). Flow cytometry was used to determine the cell cycle phases, and reverse transcription polymerase chain reaction (RT-PCR) was used to measure the levels of E2F-1 or p300.

RESULTSAfter treatment with DOX, the expression of p53 and p21 was increased, whereas that of survivin was reduced during 24 hours of the treatment. After transfection the p21 level was 2100.1-fold or 980.9-fold enhanced in comparison with that in HepG2 cells or HepG2-pEGFP cells. Survivin level was markedly down-regulated to 0.5% or 0.6% relative to that in the other two groups, nevertheless, significant p53 changes were not observed. Overexpression of p21 resulted in G1/G0 phase arrest (F = 31.59, P < 0.01), meanwhile, E2F-1 mRNA or p300 mRNA were less expressed compared with that in the other controls (F(E2F-1) = 125.28, P < 0.05; Fp300 = 46.01, P < 0.01).

CONCLUSIONp21 could be a potential mediator of survivin suppression at transcription level in HepG2 cells, which might be through the block at G1/G0 phase and down-regulation of transcription factors E2F-1 and p300.

Antibiotics, Antineoplastic ; pharmacology ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; physiology ; Doxorubicin ; pharmacology ; E2F1 Transcription Factor ; genetics ; metabolism ; G1 Phase ; Gene Expression Regulation, Neoplastic ; Hep G2 Cells ; Humans ; Inhibitor of Apoptosis Proteins ; Microtubule-Associated Proteins ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Resting Phase, Cell Cycle ; Transfection ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; p300-CBP Transcription Factors ; genetics ; metabolism

OBJECTIVETo investigate the therapeutic effects and mechanisms of using artemisinin (Art) combined with glucocorticoid (GC) to treat lupus nephritis (LN) mice.

METHODSForty hybrid female mice were randomly and equally divided into four groups with the method of random number table: control group, model group, prednisone group administrated with 6.45 mg/(kg·d) prednisone suspension, and Art+prednisone group administrated with 150 mg/(kg·d) Art suspension and 3.225 mg/(kg·d) prednisone suspension. A mice model of LN was established by injection with living lymph cell suspension. The changes of urine protein/24h, the expressions of GC receptor α (GRα) mRNA, GC receptor β (GRβ) mRNA in peripheral blood mononuclear cells (PBMCs), and transcriptional coactivator P300/CBP protein in renal tissue were measured.

RESULTSCompared with the model group, the treatment groups had significant decrease in urine protein/24 h, and renal pathological lesion (P<0.01). In the same groups, the expression of transcriptional coactivator P300/CBP protein in renal tissue and GRα mRNA were significantly increased, and GRβ mRNA expression was significantly decreased (P<0.01). And the Art+prednisone group has a better therapeutic effect than the prednisone group (P<0.01).

CONCLUSIONSArt has therapeutic sensitization effects on GC in the LN mice. The underlying mechanism could be correlated with the effect of Art on the increase of the expressions of GRα mRNA and transcriptional coactivator P300 300/CBP protein in renal tissue and on the decrease of the expression of GRβ mRNA in PBMC.

Animals ; Artemisinins ; administration & dosage ; pharmacology ; Base Sequence ; DNA Primers ; Disease Models, Animal ; Electrophoresis, Agar Gel ; Female ; Lupus Nephritis ; genetics ; metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Inbred DBA ; Prednisone ; administration & dosage ; pharmacology ; RNA, Messenger ; genetics ; Receptors, Glucocorticoid ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; p300-CBP Transcription Factors ; metabolism

OBJECTIVE: To explore the clinical characteristics and genetic etiology of a child with Rubinstein-Taybi syndrome (RSTS). METHODS: A child who was admitted to the Children's Hospital of Soochow University on October 3, 2021 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples of the child and his parents were collected. The child was subjected to whole exome sequencing (WES), and candidate variant was verified by Sanger sequencing of his family members and bioinformatic analysis. RESULTS: The patient, a 9-year-and-４-month-old boy, had manifested unique facies, microcephaly, broad toes, growth retardation, and intellectual impairment. WES revealed that he has harbored a heterozygous c.3604G>T (p.E1202*) variant in exon 20 of the EP300 gene. Sanger sequencing confirmed that neither of his parents has carried the same variant. The variant was not found in the Shenzhou Genome data Cloud, ExAC, 1000 Genomes and gnomAD databases．Analysis with SIFT, PolyPhen-2 and CADD online software has predicted the variant to be harmful. Based on the guidelines formulated by the American College of Medical Genetics and Genomics, the variant was rated as pathogenic (PVS1＋PS2＋PM2_Supporting) . CONCLUSION The heterozygous c.3604G>T variant of the EP300 gene probably underlay the RSTS type 2 in this child. Above finding has also expanded the variation spectrum of the EP300 gene.
Child ; Humans ; Male ; Computational Biology ; E1A-Associated p300 Protein/genetics* ; Exons ; Face ; Facies ; Rubinstein-Taybi Syndrome/genetics*

Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.
Cell Hypoxia ; Disulfides ; pharmacology ; Drug Screening Assays, Antitumor ; E1A-Associated p300 Protein ; antagonists & inhibitors ; HEK293 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; antagonists & inhibitors ; Indole Alkaloids ; pharmacology ; Two-Hybrid System Techniques