Resistant gonococci are very prevalent in many countries, particularly in Asia. This study was conducted to determine the trend of resistance, the effect of decreasing the ciprofloxacin susceptibilities of gonococci on the prevalence of penicillinase-producing N. gonorrhoeae (PPNG), and to compare the epidemiology of strains with the previous studies. A total of 602 strains of gonococci were isolated from prostitutes in 1997-1999. Antimicrobial susceptibility was tested by NCCLS disk diffusion and agar dilution methods. For epidemiologic analysis, vplasmid analysis and pulsed-field gel electrophoresis (PFGE) were performed. The proportion of PPNG remained high (79%), and the strains with decreased susceptibility to ciprofloxacin increased significantly from 67% in 1997 to 84% in 1999. Compared to our previous study, the PFGE patterns were similar, while the proportion of strain with the 3.2-MDa plasmid markedly decreased. In conclusion, a rapid increase in ciprofloxacin-nonsusceptible strains may suggest difficulties in the treatment of gonococcal infections in the near future with the drug. The recent decrease of PPNG with the 3.2-MDa plasmid may suggest that there is an epidemiological change in gonococcal infections, and the prevalence of related PFGE patterns suggests the dissemination of a few clones among the high risk populations.
DNA/genetics* ; DNA/drug effects ; Drug Resistance, Microbial/genetics* ; Electrophoresis, Gel, Pulsed-Field ; Endonucleases/pharmacology ; Female ; Human ; Neisseria gonorrhoeae/genetics* ; Plasmids/genetics*

OBJECTIVETo investigate the effect of ERCC1 gene on the repair capability of damaged DNA in lung cancer A549 cells induced by benzo[a]pyrene.

METHODSRecombinant plasmid expressing ERCC1 antisense RNA was constructed and transfected into A549 cells by Lipofectin reagent. The stable-transfected cell colonies were selected by hygromycin. Cell viability was determined by the MTT assay. The level of ERCC1 mRNA was measured by Northern Blot analysis. Single cell gel electrophoresis assay was applied to determine the cellular DNA damage and fifty cells for each group were counted.

RESULTSSeven positive colonies expressing ERCC1 antisense RNA were screened. There was no growth rate difference between the antisense-transfected cells and the parental cells. The endogenous mRNA level in transfected colonies decreased in varied degrees, i.e. 12% approximately 86% of that of the parental cells in Northern Blot assay. After 24 h treatment of 10 micro mol/l benzo[a]pyrene, the repair capability for DNA damage in transfected colonies was reduced to 29% approximately 71% of that of the parental cells. Also, a statistically significant correlation was observed between expression of ERCC1 mRNA and repair capability (r = 0.84).

CONCLUSIONAntisense ERCC1 RNA decreased the repair capability for damaged DNA in lung cancer cells induced by benzo[a]pyrene.

Benzo(a)pyrene ; toxicity ; Cell Line, Tumor ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; DNA-Binding Proteins ; genetics ; metabolism ; pharmacology ; Endonucleases ; genetics ; metabolism ; pharmacology ; Humans ; Lung Neoplasms ; pathology ; Plasmids ; RNA, Antisense ; pharmacology ; RNA, Messenger ; metabolism ; Repressor Proteins ; Transfection

OBJECTIVETo explore the effect of peimine on excision repair cross-complementation 1 (ERCC1) mRNA and lung resistant protein (LRP) expressions in A549/cisplatin (DDP) multidrug resistance (MDR) cell line.

METHODSLung cancer A549/DDP cells were cultured in vitro.Cells at logarithmic growth phase were divided into 4 groups, i.e., the blank control group, the DDP group, the ligustrazine group (DDP+ligustrazine), the peimine group (DDP + peimine). After 48-h drug action, ERCC1 mRNA expression was detected by RT-PCR and LRP expression detected by cell immunofluorescence.

RESULTSThere was no statistical difference in expression levels of ERCC1 mRNA and LRP between the DDP group and the blank control group (P > 0.05). Compared with the DDP group, expression levels of ERCC1 mRNA and LRP obviously decreased in the ligustrazine group and the peimine group (P < 0.05). They were obviously lower in the peimine group than in the ligustrazine group (P < 0.05).

CONCLUSIONSPeimine could reverse MDR of A549/DDP cell line. Its mechanism might be associated with down-regulating ERCC1 mRNA and LRP expression levels.

Cell Line, Tumor ; Cevanes ; pharmacology ; Cisplatin ; DNA-Binding Proteins ; genetics ; Down-Regulation ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; drug effects ; Endonucleases ; genetics ; Humans ; Low Density Lipoprotein Receptor-Related Protein-1 ; genetics ; Lung Neoplasms ; RNA, Messenger ; metabolism

Adult ; Aged ; Antineoplastic Agents ; pharmacology ; therapeutic use ; DNA-Binding Proteins ; genetics ; metabolism ; Drug Therapy, Combination ; Endonucleases ; genetics ; metabolism ; Female ; Fluorouracil ; pharmacology ; therapeutic use ; Humans ; Male ; Middle Aged ; Organoplatinum Compounds ; pharmacology ; therapeutic use ; RNA, Messenger ; drug effects ; metabolism ; Statistics as Topic ; Stomach Neoplasms ; drug therapy ; genetics ; metabolism ; Survival Analysis ; Treatment Outcome

OBJECTIVETo study the relationship between nucleotide excision repair gene ERCC1 and resistance to cisplatin in ovarian cancer.

METHODSThe expression of gene ERCC1 in 58 ovarian cancer tissues and 4 cell lines were examined and its relationship with resistance to cisplatin were analyzed, the changes of sensitivity to cisplatin were observed after interference of ERCC1 gene with small interfering RNA (siRNA) in ovarian cancer cell lines.

RESULTSIn 58 ovarian cancer tissues, the positive rate of ERCC1 protein in chemoresistant cases (57.89%) was higher than that in chemo-sensitive cases (28.21%, P = 0.029). The mRNA levels of ERCC1 gene in ovarian cancer cell lines ES-2, SKOV3, COC1, COC1/DDP were related to cisplatin IC50 values (r = 0.932, P <0.05). The sensitivity of cell lines ES-2, SKOV3, COC1/DDP cells to cisplatin was increased by 53.88, 5.07, and 3.75 times, respectively, after RNA interfering ERCC1 gene.

CONCLUSIONERCC1 gene is associated with the resistance to cisplatin and the sensitivity to cisplatin can be enhanced by RNA interfering ERCC1 in ovarian cancer.

Adult ; Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cisplatin ; pharmacology ; DNA Repair ; DNA-Binding Proteins ; genetics ; metabolism ; Drug Resistance, Neoplasm ; Endonucleases ; genetics ; metabolism ; Female ; Humans ; Inhibitory Concentration 50 ; Middle Aged ; Ovarian Neoplasms ; genetics ; metabolism ; pathology ; RNA Interference ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; genetics ; Transfection ; Young Adult

OBJECTIVETo investigate the correlations between the resistant degree of Tca8113 agaist carboplatin and the expression of excision repair cross-complementation 1 (ERCC-1).

METHODSTca8113 cells were exposed in the carboplatin solutions of gradually increasing concentration. Cancer cells were divided into six experimental groups and a control group. In the course of culture, the half inhibitory concentration (IC(50)) of each groups were detected by methyl thiazolyl tetrazolium (MTT). The expressions of ERCC-1 at mRNA and protein level were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting.

RESULTSWith the increase of drug resistance, the expression of ERCC-1 increased gradually at mRNA level (control group: 0.84 ± 0.06, group 1: 0.96 ± 0.06, group 2: 1.07 ± 0.11, group 3: 1.13 ± 0.09, group 4: 1.19 ± 0.08, group 5: 1.29 ± 0.07, group 6: 1.47 ± 0.08), values between neighboring or interval groups have significant differences (P < 0.05); the expression of ERCC-1 increased gradually at protein level (control group: 0.69 ± 0.05, group 1: 0.86 ± 0.04, group 2: 1.01 ± 0.04, group 3: 1.24 ± 0.09, group 4: 1.44 ± 0.14, group 5: 1.56 ± 0.19, group 6: 1.88 ± 0.22), values between neighboring or interval groups have significant differences (P < 0.05). The gradually increasing RT-PCR gray values were related to the gradually increasing IC(50) in all groups (r = 0.91, P < 0.01), and the gradually increasing western blotting gray values were also related to the gradually increasing IC(50) in all groups (r = 0.88, P < 0.01).

CONCLUSIONSThe high expression of ERCC-1 may become an indicator of Tca8113 resisting carboplatin. This might provide a potential target to reverse tongue squamous cell cancer (Tca8113) that has resistance to carboplatin.

Antineoplastic Agents ; pharmacology ; Blotting, Western ; Carboplatin ; pharmacology ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Cell Line, Tumor ; DNA-Binding Proteins ; genetics ; metabolism ; Drug Resistance, Neoplasm ; Endonucleases ; genetics ; metabolism ; Humans ; Inhibitory Concentration 50 ; RNA, Messenger ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tongue Neoplasms ; metabolism ; pathology

OBJECTIVETo assay the expression of cytidine deaminase (CDA), ribonucleotide reductase subunit 1 (RRM1), phosphatase and tensin homologue deleted from chromosome 10 (PTEN), excision repair cross-complementation group 1 (ERCC1), deoxycytidine kinase (dCK) and RRM1(-)37A/C polymorphism, which have been shown relevant to gemcitabine resistance in two human gemcitabine-resistant non-small cell lung cancer cell lines A549/Gem and NCI-H460/Gem, so as to make clear how do they vary during the course of acquiring resistance to gemcitabine.

METHODSThe human gemcitabine-resistant non-small cell lung cancer cell lines A549/Gem and NCI-H460/Gem were established in our Department by repeated clinical serum peak concentration and gradually increasing doses. Real-time fluorescent quantitative PCR was used to examine the expression of CDA, RRM1, PTEN, ERCC1, dCK and RRM1(-)37A/C polymorphism in those cell lines at different time points during their induction process.

RESULTSThe resistance indexes of A549/Gem and NCI-H460/Gem cells reached 163.228 and 181.684, and then remained stable at 115.297 and 129.783, respectively. The expression of CDA, RRM1, PTEN and ERCC1 varied along with the changing gemcitabine resistance indexes, but expression of dCK did not change apparently. The wild type promoter was able to amplify the genomic DNA in different induction stages of A549/Gem and NCI-H460/Gem cells, but allelotype did not, indicating that the gene type of A549/Gem, NCI-H460/Gem and their parental cells remaining still wild type.

CONCLUSIONCompared with their parental cells, the expressions of CDA, RRM1, PTEN and ERCC1 in human gemcitabine-resistant non-small cell lung cancer cell lines A549/Gem and NCI-H460/Gem rise, the expression of dCK changes inapparently, therefore, their gene type are remaining wild type.

Antimetabolites, Antineoplastic ; pharmacology ; Carcinoma, Large Cell ; genetics ; metabolism ; pathology ; Carcinoma, Non-Small-Cell Lung ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Cytidine Deaminase ; genetics ; metabolism ; DNA-Binding Proteins ; genetics ; metabolism ; Deoxycytidine ; analogs & derivatives ; pharmacology ; Deoxycytidine Kinase ; genetics ; metabolism ; Drug Resistance, Neoplasm ; Endonucleases ; genetics ; metabolism ; Humans ; Lung Neoplasms ; genetics ; metabolism ; pathology ; PTEN Phosphohydrolase ; genetics ; metabolism ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic ; RNA, Messenger ; metabolism ; Tumor Suppressor Proteins ; genetics ; metabolism