No abstract available.
Child, Preschool ; Cryptococcosis/drug therapy* ; Cytosine/analogs & derivatives* ; Female ; Flucytosine/therapeutic use* ; Human

Cytosine-substituted mildiomycin analogue (MIL-C) was produced effectively by supplementing cytosine into the culture of Streptoverticillium rimofaciens. In order to improve the yield of MIL-C, statistically-based experimental designs were applied to optimize the fermentation medium for S. rimofaciens ZJU 5119. Fifteen culture conditions were examined for their significances on MIL-C production using Plackett-Burman design. The Plackett-Burman design and one-variable-at-a-time design indicated that glucose and rice meal as the complex carbon sources, and peanut cake meal and NH4NO3 as the complex nitrogen sources were beneficial for MIL-C production in S. rimofaciens ZJU 5119. The results of further central composition design (CCD) showed that the optimal concentration of glucose, rice meal and peanut cake meal were 18.7 g/L, 64.8 g/L and 65.1 g/L, respectively. By using this optimal fermentation medium, the MIL-C concentration was increased up to 1336.5 mg/L, an approximate 3.8-fold improvement over the previous concentration (350.0 mg/L) with un-optimized medium. This work will be very helpful to the large-scale production of MIL-C in the future.
Anti-Bacterial Agents ; biosynthesis ; Culture Media ; Cytosine ; analogs & derivatives ; biosynthesis ; Fermentation ; Streptomycetaceae ; metabolism

The purpose of this study was to explore the effect of epigallocatechin-3-galate (EGCG) on acute monocytic leukemia cell line U937 and its relevant mechanism. The viability of U937 cells were assayed by SRB method. The cell cycle of U937 cells was analyzed by flow cytometry. The mRNA and protein expression of p16 gene were detected by RT-PCR and Western blot, respectively. Methylation level of U937 cells was analyzed by n-MSP. The mRNA expression of DNA methyltransferase 1 (DNMT1), DNMT3A and DNMT3B genes were analyzed by RT-PCR. The results showed that EGCG could inhibit the growth of U937 cells significantly in dose-and time-dependent manners (r=0.71), and induce the G0/G1 arrest of U937 cells in dose-dependent manner. EGCG could up-regulate the mRNA and protein expression of P16 gene in U937 cells in dose-dependent manner. EGCG could down-regulate the methylation level of p16 gene in U937 cells in dose-dependent manner. EGCG could down-regulate the mRNA expression of DNMT3A, DNMT3B genes, while did not influence the mRNA expression of DNMT1 gene. It is concluded that EGCG can up-regulate the mRNA and protein expression of p16 gene by demethylation or/and by inhibiting DNMT3A and DNMT3B genes, leading, in turn, to G0/G1 arrest and growth inhibition of U937 cells.
Catechin ; analogs & derivatives ; pharmacology ; Cell Proliferation ; drug effects ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases ; metabolism ; DNA Methylation ; Gene Expression Regulation, Leukemic ; Genes, p16 ; Humans ; Leukemia, Monocytic, Acute ; genetics ; U937 Cells

The study was purposed to investigate the possible mechanism of epigallocatechin-3-gallate (EGCG) induced p16 gene demethylation and transcription regulation in the malignant lymphoma cell line-CA46. The induced growth inhibition of CA46 cells was assayed by growth curve and MTT; the DNA content of CA46 cells was analyzed by flow cytometry after being exposed to EGCG; the methylation status of the p16 gene in CA46 cell line before and after treatment with EGCG was detected by the nested-methylation specific PCR and DNA sequencing; the mRNA of p16 and DNA methyltransferases (DNMT3A and DNMT3B) gene were determined by RT-PCR. The results showed that in comparison with the control, all the 3 different concentration of EGCG were able to inhibit the growth of malignancy cell lines and increase the cell number in G(0)/G(1) phase. After treatment with EGCG for 48 hours, the methylation level was apparently attenuated in a concentration-dependent manner. Expression of p16 gene in untreated group was mild while in the treated groups it had been greatly strengthened, as compared with untreated group, the gray scale ratio of p16 to beta-actin 1 treated with EGCG (6, 12, 24) microg/ml was increased from (0.05 +/- 0. 01) to (0.19 +/- 0.03), (0.39 +/- 0.10), (0.85 +/- 0.09) respectively, exhibiting a significant difference (p < 0.05); as compared with the untreated group, after treatment with EGCG for 48 hours, the expressions of DNMT3A and DNMT3B were obviously down-regulated. It is concluded that EGCG can activate and up-regulate the expression of p16 gene mRNA which inhibits the proliferation of CA46 cell through inducing the G(0)/G(1) arrest by demethylation and/or by inhibiting DNMT3A and DNMT3B gene.
Catechin ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; DNA (Cytosine-5-)-Methyltransferases ; metabolism ; DNA Methylation ; Gene Expression Regulation, Neoplastic ; Genes, p16 ; Humans ; Lymphoma ; genetics ; Transcription, Genetic

Adenine ; analogs & derivatives ; chemistry ; pharmacology ; Animals ; Anti-HIV Agents ; chemistry ; pharmacology ; Antiviral Agents ; chemistry ; pharmacology ; Arabinofuranosyluracil ; analogs & derivatives ; chemistry ; pharmacology ; Cytosine ; analogs & derivatives ; chemistry ; pharmacology ; Dioxolanes ; chemistry ; pharmacology ; Humans ; Molecular Structure ; Nucleosides ; chemistry ; pharmacology ; Organophosphonates ; chemistry ; pharmacology ; Purine Nucleosides ; chemistry ; pharmacology ; Tenofovir

Sapacitabine is an orally bioavailable prodrug of the nucleoside analog 2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofuranosylcytosine (CNDAC). Both the prodrug and active metabolite are in clinical trials for hematologic malignancies and/or solid tumors. CNDAC has a unique mechanism of action: after incorporation into DNA, it induces single-strand breaks (SSBs) that are converted into double-strand breaks (DSBs) when cells go through a second S phase. In our previous studies, we demonstrated that CNDAC-induced SSBs can be repaired by the transcription-coupled nucleotide excision repair pathway, whereas lethal DSBs are mainly repaired through homologous recombination. In the current work, we used clonogenic assays to compare the DNA damage repair mechanism of CNDAC with two other deoxycytidine analogs: cytarabine, which is used in hematologic malignacies, and gemcitabine, which shows activity in solid tumors. Deficiency in two Rad51 paralogs, Rad51D and XRCC3, greatly sensitized cells to CNDAC, but not to cytarabine or gemcitabine, indicating that homologous recombination is not a major mechanism for repairing damage caused by the latter two analogs. This study further suggests clinical activity and application of sapacitabine that is distinct from that of cytarabine or gemcitabine.
Animals ; Antimetabolites, Antineoplastic ; pharmacology ; Arabinonucleosides ; pharmacology ; CHO Cells ; Cricetinae ; Cricetulus ; Cytarabine ; analogs & derivatives ; pharmacology ; Cytosine ; analogs & derivatives ; pharmacology ; DNA Breaks, Double-Stranded ; drug effects ; DNA Repair ; drug effects ; DNA-Binding Proteins ; deficiency ; Deoxycytidine ; analogs & derivatives ; pharmacology ; Homologous Recombination ; genetics ; Inhibitory Concentration 50 ; Prodrugs

Although methyltransferase has been recognized as a major element that governs the epigenetic regulation of the genome during temozolomide (TMZ) chemotherapy in glioblastoma multiforme (GBM) patients, its regulatory effect on glioblastoma chemoresistance has not been well defined. This study investigated whether DNA methyltransferase (DNMT) expression was associated with TMZ sensitivity in glioma cells and elucidated the underlying mechanism. DNMT expression was analyzed by western blotting. miR-20a promoter methylation was evaluated by methylation-specific PCR. Cell viability and apoptosis were assessed using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and TdT-mediated dUTP-biotin nick end labeling assays, respectively. The results showed that compared with parental U251 cells, DNMT1 expression was downregulated, miR-20a promoter methylation was attenuated and miR-20a levels were elevated in TMZ-resistant U251 cells. Methyltransferase inhibition by 5-aza-2\'-deoxycytidine treatment reduced TMZ sensitivity in U251 cells. In U251/TM cells, DNMT1 expression was negatively correlated with miR-20a expression and positively correlated with TMZ sensitivity and leucine-rich repeats and immunoglobulin-like domains 1 expression; these effects were reversed by changes in miR-20a expression. DNMT1 overexpression induced an increase in U251/TM cell apoptosis that was inhibited by the miR-20a mimic, whereas DNMT1 silencing attenuated U251/TM cell apoptosis in a manner that was abrogated by miR-20a inhibitor treatment. Tumor growth of the U251/TM xenograft was inhibited by pcDNA-DNMT1 pretreatment and boosted by DNMT1-small hairpin RNA pretreatment. In summary, DNMT1 mediated chemosensitivity by reducing methylation of the microRNA-20a promoter in glioma cells.
Animals ; Antineoplastic Agents, Alkylating/*pharmacology/therapeutic use ; Apoptosis/drug effects ; Brain/drug effects/metabolism/pathology ; Brain Neoplasms/drug therapy/*genetics/pathology ; DNA (Cytosine-5-)-Methyltransferase/antagonists & inhibitors/*genetics/metabolism ; DNA Methylation ; Dacarbazine/*analogs & derivatives/pharmacology/therapeutic use ; Drug Resistance, Neoplasm ; Female ; Gene Expression Regulation, Neoplastic ; Glioma/drug therapy/*genetics/pathology ; Humans ; Mice, Inbred C57BL ; MicroRNAs/*genetics ; Promoter Regions, Genetic

OBJECTIVETo study clinical characteristics of refractory or relapsed DNMT3A⁺ cytogenetically normal acute myeloid leukemia（CN-AML）patients, and to explore the overall response rate（ORR）and side effects of these patients followed the therapy including decitabine with CAG or CAGlike regimen.

METHODSIn this study we retrospectively analyzed 53 refractory or relapsed CN- AML patients receiving the therapy including decitabine combined with CAG and CAG- like regimen in our center from April 2011 to October 2014. The clinical characteristics and ORR were further analyzed. Based on gene mutations, these patients could be divided into 2 groups: DNMT3A⁺ AML patients（n=24）and DNMT3A- AML patients（n=29）.

RESULTSThe median age of DNMT3A⁺AML patients was 46 years old, higher white blood cells and bone marrow blasts were observed in DNMT3A+ AML group. The ORR and complete response（CR）rate of DNMT3A+ group were 62.50% and 54.17%, respectively. No differences were observed in ORR and CR rates（P>0.05）between these two groups. DNMT3A⁺/FLT3-ITD⁺ CN-AML patients（n=14）had higher ORR and CR rates than DNMT3A-/FLT3-ITD⁺CN- AML patients（n=15）（P= 0.040 and 0.042, respectively）. The one- year overall survival （OS） of DNMT3A⁺ AML group and DNMT3A- AML group were 59.58% , 54.09% , no differences were observed （P=0.438）. 25 patients received further therapy of allo-HSCT, the one-year OS of DNMT3A⁺ CN-AML was 87.50% and one-year disease free survival（DFS）was 72.73%, while the one- year OS was 61.54% and one- year DFS was 58.02% in DNMT3A⁻ group. No differences were observed between 2 groups （P=0.456, 0.217）.

CONCLUSIONDecitabine combined with CAG or CAG-like regimen was an effective and safe treatment for refractory or relapsed CN- AML patients. Compared to DNMT3A⁻/FLT3- ITD⁺ CN- AML patients, DNMT3A⁺/ FLT3-ITD⁺ CN-AML patients had higher ORR and CR rates. Decitabine bridged hematopoietic stem cells transplant could likely improve the survival of refractory or relapsed CN-AML patients.

Aclarubicin ; therapeutic use ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Azacitidine ; analogs & derivatives ; therapeutic use ; Cytarabine ; therapeutic use ; DNA (Cytosine-5-)-Methyltransferases ; genetics ; Disease-Free Survival ; Granulocyte Colony-Stimulating Factor ; therapeutic use ; Humans ; Leukemia, Myeloid, Acute ; genetics ; therapy ; Mutation ; Remission Induction ; Retrospective Studies

OBJECTIVE: To analyze the effect of DNA hypermethylation on NOR1 promoter activity and expression. METHODS: NOR1 promoter plasmids were treated with SssI methyltransferase. The plasmids were modified by sodium bisulfite and purified. Sodium bisulfite-modified plasmids were subjected to PCR with primers designed to analyze the methylation status of 26 CpG sites in a 311-bp region of the NOR1 promoter. Cells were transfected by methylated or mock-methylated promoter plasmids. The promoter activities were assessed by the luciferase levels of cell lysates or by directly observing GFP expression under fluorescence microscope. HL60 cells were treated with different concentrations of 5-aza-dC. Total RNA was isolated from harvested cells. Real-time RT-PCR was used to measure the expression level of NOR1 mRNA. RESULTS: Bisulfite sequencing confirmed that SssI methyltransferase treatment successfully resulted in intensive hypermethylation of the NOR1 promoter plasmids. The promoter activity of NOR1 promoter plasmids was totally blocked by SssI methyltransferase treatment. NOR1 expression levels in HL60 cells were restored by 5-aza-dC treatment. CONCLUSION NOR1 promoter plasmids are intensively hypermethylated by SssI methyltransferase treatment. The promoter activity of NOR1 promoter plasmids are totally blocked by SssI methyltransferase treatment. The 5-aza-dC treatment may restore the endogenous NOR1 mRNA level in HL60 cells.
Azacitidine ; analogs & derivatives ; pharmacology ; Base Sequence ; Cell Line, Tumor ; CpG Islands ; DNA Methylation ; DNA Modification Methylases ; antagonists & inhibitors ; DNA-Cytosine Methylases ; pharmacology ; Decitabine ; Epigenesis, Genetic ; Gene Silencing ; HL-60 Cells ; Humans ; Membrane Transport Proteins ; genetics ; metabolism ; Molecular Sequence Data ; Nasopharyngeal Neoplasms ; pathology ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; genetics ; metabolism

ObjectiveTo explore the inhibitory effect of polyphyllin Ⅰ (PPⅠ) on the proliferation of castration-resistant prostate cancer PC3 cells and its molecular mechanism.

METHODSWe cultured human prostate cancer PC3 cells in vitro and treated them with PPⅠ at the concentrations of 0 (blank group), 0.4, 0.8, 1.2, 1.6, 2.0, and 2.4 μmol/L for 24, 48, and 72 hours, respectively. Then we detected the proliferation of the cells by MTT assay, measured their apoptosis by flow cytometry, and determined the expressions of p-ERK1/2, ERK1/2, NF-κB/p65 and DNMT1 proteins as well as the level of NF-κB/p65 in the cells additionally treated with the ERK1/2 inhibitor SP600125 by Western blot.

RESULTSCompared with the blank control group, the PPⅠ-treated PC3 cells showed a concentration- and time-dependent reduction of the survival rate (1.00 ± 0.00 vs 0.85 ± 0.05, P < 0.01) at 0.4 μmol/L after 48 hours of intervention, concentration-dependent early apoptosis at 0.8 μmol/L (4.83 ± 0.95 vs 13.83 ± 2.97, P < 0.01), time-dependent increase of the expressions of p-ERK1/2 (1.00 ± 0.00 vs 1.73 ± 0.17, P < 0.01) and ERK1/2 (1.00 ± 0.00 vs 1.36 ± 0.12, P < 0.01) at 2 hours, and concentration-dependent decrease of the expressions of NF-κB/p65 and DNMT1 at 1.2 μmol/L (1.00 ± 0.00 vs 0.78 ± 0.10 and 0.63 ± 0.06, P < 0.01) and 1.6 μmol/L (1.00 ± 0.00 vs 0.67 ± 0.11 and 0.52 ± 0.09, P<0.01). Inhibition of ERK1/2 phosphorylation with PD98059 markedly reversed PPⅠ-induced decrease of the NF-κB/p65 expression as compared with that in the PPⅠ group (0.86 ± 0.18 vs 0.43 ± 0.09, P < 0.05).

CONCLUSIONSPPⅠ induces the early apoptosis and suppresses the proliferation of PC3 cells, probably by activating the ERK1/2 pathway and inhibiting the expressions of the NF-κB/p65 and DNMT1 proteins.

Apoptosis ; Cell Proliferation ; drug effects ; DNA (Cytosine-5-)-Methyltransferase 1 ; metabolism ; Diosgenin ; analogs & derivatives ; pharmacology ; Flavonoids ; metabolism ; Humans ; MAP Kinase Signaling System ; Male ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; NF-kappa B ; metabolism ; PC-3 Cells ; Phosphorylation ; Prostatic Neoplasms, Castration-Resistant ; drug therapy ; metabolism ; pathology ; Signal Transduction ; Transcription Factor RelA ; metabolism