OBJECTIVETo investigate the function of POLH(polymerase eta) through establishment of the POLH gene-blocked cell line FL-POLH(-).

METHODSA mammalian expression vector expressing antisense POLH gene fragment pMAMneo-amp-POLHA (-) was constructed by cloning the 1473 - 2131 fragment of POLH gene into the mammalian expression vector pMAMneo-amp(-) in antisense orientation. The FL cells were transfected with this antisense RNA expressing vector and selected by G418. The mutation assay was conducted using the shuttle plasmid pZ189.

RESULTThe spontaneous mutation frequency of SupF tRNA gene in the plasmid replicated in the FL-POLH(-) was 13.5 x 10(-4), while it was 4.9x10(-4) and 3.7x10(-4) in the control cells FL and FL-M, respectively. The nontargeted mutation frequency of SupF tRNA gene decreased in the plasmid replicated in these cell lines pretreated with MNNG.

CONCLUSIONPOLH plays an important role in maintenance of genetic stability and genesis of nontargeted mutation.

Antisense Elements (Genetics) ; pharmacology ; Cell Line ; DNA-Directed DNA Polymerase ; genetics ; physiology ; Methylnitronitrosoguanidine ; toxicity ; Mutagenesis

DNA, Viral ; genetics ; Hep G2 Cells ; Hepatitis B virus ; drug effects ; Humans ; Oligonucleotides, Antisense ; pharmacology

OBJECTIVETo construct a recombinant adenovirus vector carrying antisense heat shock protein 70 (HSP70) cDNA and observe its effect on inhibiting the growth of laryngeal carcinoma Hep-2 cells.

METHODSThe HSP70 gene fragment encoding the 5' region was cloned reversely into the shuttle plasmid PAdTrack-CMV, and the resultant plasmid was recombined with the backbone plasmid PadEasy-1 in the E.coli Bj5183 cells to generate the recombinant adenovirus vector. The adenovirus were then packaged and amplified in 293 cells, and the viral titer was determined using GFP.

RESULTSThe recombinant adenovirus vector carrying antisense HSP70 cDNA was constructed successfully with a viral titer of 8 x 10(9). HSP70 expression of Hep-2 cells was obviously blocked by antisense HSP70 RNA, and Western blotting and immuohistochemistry demonstrated that cells transfected with antisense HSP70 did not express or express HSP70 at low levels. Flow cytometry presented apoptotic peak in the antisense HSP70-transfected cells, but not in the control cells.

CONCLUSIONThe recombinant adenovirus vector containing antisense HSP70 cDNA can effectively deliver antisense HSP70 gene into Hep-2 cells, suggesting the great potential of this gene therapy strategy in management of human laryngeal carcinoma.

Adenoviridae ; genetics ; Cell Line, Tumor ; DNA, Antisense ; pharmacology ; DNA, Complementary ; genetics ; Genetic Therapy ; Genetic Vectors ; biosynthesis ; HSP70 Heat-Shock Proteins ; genetics ; Humans ; Laryngeal Neoplasms ; therapy ; RNA, Antisense ; pharmacology ; Transfection

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

To explore the effect of human telomerase reverse transcriptase (hTERT) gene antisense oligodeoxynucleotide (ASODN) on telomerase activity in primary acute myeloid leukemia (AML) cells and chronic myeloid leukemia (CML) cells, polymerase chain reaction enzyme-linked immunosorbent assay (PCR-ELISA) was used to determine telomerase activity. The expression levels of hTERT protein were assayed by flow cytometry using immunofluorescence labeling. Immunofluorescence assay showed that the expression levels of hTERT protein in AML and CML cells decreased with time after hTERT ASODN treatment. There was no difference in hTERT protein levels between control and sense oligodeoxynucleotide (SODN)-treated cells. Telomerase activity decreased when AML and CML cells were treated with ASODN for 48 h. Telomerase activity of AML and CML cells was significantly inhibited when the cells treated with ASODN for 72 h. There was no difference in telomerase activity levels between control and hTERT SODN-treated cells. It was concluded that hTERT ASODN could inhibit hTERT protein expression level, thus decreasing the telomerase activity in primary AML and CML cells.
Adolescent ; Adult ; DNA-Binding Proteins ; Female ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; enzymology ; Leukemia, Myeloid, Acute ; enzymology ; Male ; Middle Aged ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; Telomerase ; antagonists & inhibitors ; metabolism

To explore the effect of antisense phosphorothioate oligodeoxynucleotide (ASODN) of human telomerase reverse transcriptase (hTERT) gene on telomerase activity in CEM cells, PCR enzyme-linked immunoassay was used to determine telomerase activity. The expression levels of hTERT mRNA and protein were assayed by RT-PCR and immunofluorescence assay using fluoresce isothiocyanate label respectively. The results showed that the expression levels of hTERT mRNA and protein in CEM cells decreased with time after hTERT ASODN treatment. There was no difference in hTERT mRNA and protein levels between control and sense oligodeoxynucleotide-treated cells. Telomerase activity decreased when CEM cells were treated with ASODN for 48 hours. Telomerase activity of CEM cells was significantly inhibited when treated with ASODN for 72 hours. There was no difference in telomerase activity levels between control and hTERT sense oligodeoxynucleotide-treated cells. These results suggested that hTERT ASODN inhibited telomerase activity of CEM cells.
Cell Division ; drug effects ; Cell Line ; DNA-Binding Proteins ; Flow Cytometry ; Humans ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; RNA, Messenger ; analysis ; Telomerase ; analysis ; genetics ; metabolism

BACKGROUNDCyclin B1 (CLB1) is necessary for mitotic initiation in mammalian cells and plays important roles in cancer development. Therefore, a potential strategy in cancer therapy is to suppress the activity of CLB1 by delivering antisense constructs of CLB1 into tumor cells. In previous CLB1 studies, antisense constructs with a short half life were often used and these constructs might not persistently inhibit CLB1.

METHODSWe successfully created a recombinant plasmid encoding the full-length antisense cDNA of mouse cyclin B1 (AS-mCLB1) and transfected this construct to the murine Lewis lung carcinoma (LL/2) and CT-26 colon carcinoma (CT-26) cells. We isolated clones of LL/2 and CT-26 transfectants with stable expression of AS-mCLB1. Reverse transcriptional polymerase chain reaction (RT-PCR) and Western blot were applied to detect the expression of the mRNA and protein levels of CLB1. To further test the efficacy of this strategy in vivo, AS-mCLB1-expressing LL/2 and CT-26 transfectants were implanted into mice.

RESULTSWe found the expression of the mRNA and protein levels of CLB1 decrease in these transfectants. The inhibition of CLB1 caused prominent G1 arrest, abnormal morphology, retarded cell growth and an increase in apoptosis. In AS-mCLB1-expressing LL/2 and CT-26 transfectants implanted mice, tumorigenicity was effectively suppressed compared with the controls. In addition, the expression of AS-mCLB1 also significantly increases the survival duration of implanted animals.

CONCLUSIONAS-mCLB1 is likely to be useful in future cancer therapy, which may be associated with its ability to down-regulate the expression of CLB1 and then induce G1arrest and apoptosis in tumor cells.

Animals ; Apoptosis ; Cell Proliferation ; Cell Survival ; Cyclin B ; antagonists & inhibitors ; genetics ; Cyclin B1 ; DNA, Antisense ; pharmacology ; DNA, Complementary ; pharmacology ; G1 Phase ; Mice ; Mice, Inbred C57BL ; Neoplasm Transplantation ; Neoplasms, Experimental ; pathology ; therapy

OBJECTIVETo investigate the effect of overexpression of S3 ribosomal protein (S3rp) gene on the resistance of leukemia cell to antitumor drugs.

METHODSBoth sense and antisense cDNA recombinants of S3rp gene were constructed with pcDNA3.1 expression vector. Subsequently, the sense S3rp cDNA recombinant was transfected into K562 cells while the antisense one into K562/DOX cells (a multidrug resistant cell line). In addition, empty pcDNA3.1 vector was transfected into the corresponding cells as negative controls. The chemosensitivity of cells was evaluated by MTT assay.

RESULTSSense S3rp cDNA transfected K562 cells were 5.8 times more resistant to doxorubicin than control cells did, whereas antisense S3rp cDNA transfected K562/DOX cells were 3.2 times less resistant to doxorubicin than control cells did.

CONCLUSIONOverexpression of S3rp gene plays an important role in the development of drug resistance in K562/DOX cells.

Antibiotics, Antineoplastic ; pharmacology ; DNA, Antisense ; genetics ; DNA, Complementary ; genetics ; Doxorubicin ; pharmacology ; Drug Resistance, Neoplasm ; genetics ; Gene Expression ; Humans ; K562 Cells ; Leukemia ; genetics ; pathology ; Plasmids ; genetics ; Ribosomal Proteins ; biosynthesis ; genetics ; Transfection

BACKGROUNDTo determine the feasibility of inhibition of duck hepatitis B virus (DHBV) DNA replication by antisense phosphorothioate oligodeoxynucleotides corresponding to DHBV transcription region.

METHODSThe authors designed three antisense phosphorothioate oligodeoxynucleotides which correspond to DHBV PreS1,PreS2 and S antigen gene promotors respectively. The DNA replication level was detected with Southern blot method and cpm calculation.

RESULTSPrimary duck hepatocyte culture was treated with 1.5 micromol/L antisense oligodeoxynucleotides in vitro, all the antisense fragments caused a firm inhibition of viral DNA replication and the inhibition rates were 61.5%, 69.3% and 62.4%, respectively. In vivo, the animals were treated with 10 microgram/g PreS1 antigen gene promotor antisense oligodeoxynucleotides per day for 6 days and a very strong inhibition rate of 87.9% was obtained.

CONCLUSIONSThe results demonstrated the potential clinical application of antisense phosphorothioate oligodeoxynucleotides in clinics.

Animals ; DNA Replication ; drug effects ; DNA, Viral ; drug effects ; Ducks ; Hepadnaviridae Infections ; virology ; Hepatitis B Surface Antigens ; blood ; Hepatitis B Virus, Duck ; genetics ; physiology ; Hepatitis, Viral, Animal ; virology ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; Protein Precursors ; blood ; Virus Replication ; drug effects

BACKGROUNDTransforming growth factor-beta1 (TGF-beta1) exerts strong fibrogenic potential in culture-activated HSCs. Smad4 is a key intracellular mediator for the transforming growth factor-beta (TGF-beta) superfamily of growth factors. The aim of this study was to assess the effects of the antisense Smad4 gene on Ito cell line, LI90.

METHODSThe recombinant retroviral vector pLXSN-Smad4 was constructed by cloning the rat antisense Smad4 cDNA into the retroviral vector pLXSN. Retroviruses with or without the antisense gene were obtained by transfecting pLXSN-Smad4 and pLXSN vectors into PA317 cells. Human hepatic stellate cells (HSCs) LI90 were infected with these retroviruses followed by selection with G418. The expression of Smad4 was detected by Northern and Western blots. Cell biological characteristics, including cell growth curve, 3H-TdR and 3H-proline uptake by HSCs and the production of extracellular matrix were assessed.

RESULTSmRNA and protein expressions of Smad4 in LI90 cells transfected with retrovirus containing the antisense Smad4 gene were much lower than those in LI90 cells transfected with empty vector or parental LI90 cells. Cells hypoexpressing the Smad4 gene exhibited a slower rate of growth, a lower uptake of 3H-TdR and 3H-proline (P < 0.01), and smaller production of th extracellular matrix, compared with parental LI90 cells and cells transfected with empty retrovirus.

CONCLUSIONSThe antisense Smad4 gene can suppress the expression of the Smad4 gene, reduce endogenous production of Smad4 mRNA and protein, block TGF-beta1 signaling pathway, inhibit activation of Ito cells, obstruct the growth of Ito cells, decrease the production of the extracellular matrix (ECM). Our results may provide a basis for the development of antifibrotic gene therapy.

Cell Line ; DNA, Antisense ; pharmacology ; DNA-Binding Proteins ; antagonists & inhibitors ; genetics ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; Liver Cirrhosis ; therapy ; Retroviridae ; genetics ; Smad4 Protein ; Trans-Activators ; antagonists & inhibitors ; genetics ; Transfection ; Transforming Growth Factor beta ; physiology ; Transforming Growth Factor beta1