In cancer gene therapy, restriction of antitumor transgene expression in a radiation field by use of ionizing radiation-inducible promoters is one of the promising approaches for tumor-specific gene delivery. Although tumor suppressor protein p53 is induced by low doses (<1 Gy) of radiation, there have been only a few reports indicating potential utilization of a p53-target gene promoter, such as that of the p21 gene. This is mainly because the transiently transfected promoter of p53-target genes is not much sensitive to radiation. We examined the response of the p21 gene promoter to low-dose radiation when transduced into a human breast cancer cell line MCF-7 by use of recombinant adeno-associated virus (rAAV) vectors. It was shown that the p21 gene promoter transduced by rAAV vectors was more highly radiation-responsive than that transiently transfected by electroporation. A significant induction of the p21 gene promoter by radiation of low doses down to 0.2 Gy was observed. When cells were transduced with the p21 gene promoter-driven HSVtk gene by rAAV vector, they were significantly sensitized to repetitive treatment with low dose radiation (1 Gy) in the presence of the prodrug ganciclovir. It was therefore considered that the p21 gene promoter in combination with a rAAV vector is potentially usable for the development of a low-dose radiation-inducible vector for cancer gene therapy.
X-Rays ; Tumor Cells, Cultured ; Transgenes/*radiation effects ; Transduction, Genetic ; Promoter Regions (Genetics)/*radiation effects ; Humans ; Genetic Vectors/*radiation effects ; Gene Therapy/methods ; Electroporation/methods ; Dose-Response Relationship, Radiation ; Cyclin-Dependent Kinase Inhibitor p21/*genetics ; Adenoviridae ; 3' Untranslated Regions/physiology

Light quality can regulate both psbA genes and vector promoter psbA of the engineered Synechococcus. Through light regulation, we tried to improve yield of the recombinant protein for vp28 gene-expressed Synechococcus sp. PCC7002. To drive photon-capturing efficiently, three limiting factors (irradiance, temperature and pH) were optimized by measuring net photosynthesis. High cell density cultures were performed with variant ratios of white, red and blue light in a 5-L photo-bioreactor. Yields of biomass, expressions of vp28 and transcription levels of psbA were compared. High ratio blue light-induced vp28 transcription had tripled and the relative accumulation of VP28 protein was doubled. The relative expressions of psbAII and psbAIII had positive correlations with higher ratio of blue light, not the red light. With high ratio red light inducing, dry biomass reached 1.5 g/L in three days. Therefore, we speculated that red light accelerated biomass accumulation of the transgenic strain and blue light promoted transcription for PpsbA and psbA. These results provided useful information for mass production of cyanobacteria and its secondary metabolites.
Gene Expression Regulation, Bacterial ; Light ; Photosystem II Protein Complex ; genetics ; Promoter Regions, Genetic ; Synechococcus ; genetics ; growth & development ; radiation effects

OBJECTIVETo observe the therapeutic effect of CDglyTK gene mediated by radiation-inducible promoters in the treatment of buccal carcinoma in Golden Hamster.

METHODSAnimal models of buccal carcinoma in golden hamster were established by painting 0.5% dimethyl-benzanthracene. The plasmids pcDNA (+) 3.1/E-CDglyTK were transfected into tumors by lipofectamine. 24 h later, the tumors were exposed to 3 Gy irradiation. Animals were monitored at regular intervals for volume of tumors. CDglyTK mRNA was assayed by RT-PCR. Apoptosis and proliferating cell nuclear antigen were detected respectively by in situ end-labeling and immunohistochemical methods.

RESULTSCompared with control groups, the tumor was suppressed obviously by CDglyTK gene therapy combined with 3 Gy induction radiation. The expression of CDglyTK gene could be detected by RT-PCR in the transfected tumor, and up-regulation of CDglyTK expression was found in tumor exposed to radiation (P < 0.05). There was significant difference in apoptosis index or proliferation index between tumor without irradiation and tumor with irradiation (P < 0.05).

CONCLUSIONSThe radiation-inducible promoter can be served as a molecular switch to regulate the expression of CDglyTK gene in buccal carcinoma in golden hamster, and low dose induction radiation can significantly improve the therapeutic effects.

Animals ; Carcinoma, Squamous Cell ; diagnostic imaging ; therapy ; Cheek ; diagnostic imaging ; Cricetinae ; Cytosine Deaminase ; genetics ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; methods ; Mesocricetus ; Mouth Neoplasms ; radiotherapy ; therapy ; Promoter Regions, Genetic ; radiation effects ; Radiography ; Simplexvirus ; enzymology ; Thymidine Kinase ; genetics

Animals ; Caenorhabditis elegans ; metabolism ; radiation effects ; Caenorhabditis elegans Proteins ; genetics ; metabolism ; Light ; Lysine ; analogs & derivatives ; genetics ; metabolism ; Promoter Regions, Genetic ; Protein Transport ; RNA, Transfer ; genetics ; metabolism ; Tumor Necrosis Factor Ligand Superfamily Member 14 ; metabolism

In recent years, large numbers of non-coding RNAs (ncRNAs) have been identified in C. elegans but their functions are still not well studied. In C. elegans, CEP-1 is the sole homolog of the p53 family of genes. In order to obtain transcription profiles of ncRNAs regulated by CEP-1 under normal and UV stressed conditions, we applied the 'not-so-random' hexamers priming strategy to RNA sequencing in C. elegans, This NSR-seq strategy efficiently depleted rRNA transcripts from the samples and showed high technical replicability. We identified more than 1,000 ncRNAs whose apparent expression was repressed by CEP-1, while around 200 were activated. Around 40% of the CEP-1 activated ncRNAs promoters contain a putative CEP-1-binding site. CEP-1 regulated ncRNAs were frequently clustered and concentrated on the X chromosome. These results indicate that numerous ncRNAs are involved in CEP-1 transcriptional network and that these are especially enriched on the X chromosome in C. elegans.
Animals ; Binding Sites ; Caenorhabditis elegans ; Caenorhabditis elegans Proteins ; genetics ; metabolism ; High-Throughput Nucleotide Sequencing ; Promoter Regions, Genetic ; RNA, Untranslated ; metabolism ; Sequence Analysis, RNA ; Transcriptome ; radiation effects ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; Ultraviolet Rays ; X Chromosome

OBJECTIVETo study the specific protection of myeloid cells from chemotherapeutic agents and radiation.

METHODSThe recombinant retroviral vectors containing MDR1 gene and MnSOD gene regulated by APN myeloid promoter were constructed and introduced into myeloblastic cell line KG1a and hepatoma cell line BEL7402. The resistance of the cells to antitumor drugs and radiation were analyzed by cell survival assay. In vivo, the murine bone marrow cells were isolated and infected by the retroviral particles, which were transplanted into recipient mouse treated with paclitaxel or X-ray. The murine white blood cell (WBC) was counted in order to assay the effects of MDR1 or MnSOD gene on hematopoiesis in the course of chemotherapy and radiotherapy.

RESULTSThe resistance to chemotherapeutic agents such as cochicine, Vp-16, vincristine, doxorubcin and paclitaxel were elevated markedly by 10.6, 10.4, 11.2, 4.2 and 14.2 folds in KG1a cell line transduced with MDR1 gene. The resistance to radiation increased 3.7 folds at the dose of 10 Gy compared with parental cells in KGla cell line transduced with MnSOD gene derived by APN promoter. In contrast, the chemosensitivity and the radiosensitivity showed no significant change in BEL 7402 cell line transduced with MDR1 gene and MnSOD gene. In vivo, the WBC counts in the mouse introduced with MDR1 gene or MnSOD gene were higher than those in the control mouse (P < 0.01).

CONCLUSIONThe expression of MDR1 gene and MnSOD gene regulated by APN myeloid promoter is effective on myelo-specific protection without enhancing the resistance of tumor cells in vitro. The hematopoiesis can be reconstituted in vivo during anticancer drug or radiation treatment. This study may provide experimental evidence and new clues for myeloprotection of cancer patients being treated with chemotherapy and/or radiotherapy.

ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; pharmacology ; Animals ; Antineoplastic Agents ; pharmacology ; Bone Marrow ; drug effects ; physiology ; CD13 Antigens ; genetics ; Cell Survival ; drug effects ; Drug Interactions ; Etoposide ; pharmacology ; Gene Expression Regulation ; Gene Transfer Techniques ; Genetic Vectors ; genetics ; Male ; Mice ; Mice, Inbred BALB C ; Promoter Regions, Genetic ; Protective Agents ; pharmacology ; Radiation-Protective Agents ; pharmacology ; Superoxide Dismutase ; genetics ; pharmacology ; Tumor Cells, Cultured ; Vincristine ; pharmacology

OBJECTIVETo explore the synergistic anti-tumor effect of radiotherapy and horseradish peroxidase/prodrug indole-3-acetic acid (HRP/IAA) gene therapy system using chimeric hTERT promoter responsive to ionizing radiation.

METHODSThe synthetic hTERT promoters containing four tandem-repeat copies of radio-inducible CArG elements, and the chimeric promoter containing cytomegalovirus (CMV) early promoter were both constructed. The activities of the chimeric promoters in cancer cell lines (HeLa, A549, and MHCC97) and normal cell line (MRC-5) were detected using luciferase reporter gene expression analysis after a (60)Co γ-irradiation treatment at a series of doses(a single dose of 0 to 10 Gy). The anti-tumor effect of combining irradiation with HRP/IAA gene-directed enzyme prodrug therapy system controlled by the chimeric promoter was tested by colony formation assay, cell counting and apoptosis analysis.

RESULTSThe chimeric promoters were ineffective in normal human cells, even after irradiation, but the expression of luciferase gene in tumor cells was significantly higher. The activity of the chimeric promoter in MRC-5 cells was 22.3%, 12.9% and 13.6% of that in HeLa, A549 and MHCC97 cells, respectively. After irradiation, the ratios were 11.7%, 8.7% and 8.8%, respectively. Furthermore, the chimeric promoters could successfully induce the expression of luciferase gene following different doses of radiation, with maximal inducible activity seen after 6 Gy irradiation. The chimeric promoter containing four tandem-repeat copies of radio-inducible CArG elements and CMV early promoter showed the highest activity with 6 Gy irradiation. The relative luciferase activities in HeLa, A549 and MHCC97 cells were 1.7 ± 0.2, 2.3 ± 0.2 and 2.3 ± 0.1, respectively. The chimeric promoter mediated suicide gene therapy system could increase radio-sensitivity in different cancer cells. Compared with the control system, it plus irradiation showed stronger cell proliferation inhibition, 67.3% vs. 26.1% in HeLa, 69.0% vs. 28.3% in A549, 64.6% vs. 20.8% in MHCC97 cells, and also higher apoptosis-inducing effect, 39.6% vs. 14.2% in HeLa, 33.0% vs. 12.4% in A549, and 33.2% vs. 14.2% in MHCC97 cells.

CONCLUSIONSChimeric promoter containing hTERT promoter, CArG elements and CMV promoter preserve the tumor-specificity in telomerase-positive tumor cells, and irradiation-responsive to low dose of radiation. The suicide gene therapy using this promoter plus radiotherapy show a strong anti-tumor effect in vitro. It is expected to have a good potential for future application in gene radiotherapy.

Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Combined Modality Therapy ; Cytomegalovirus ; genetics ; Genes, Transgenic, Suicide ; Genetic Therapy ; methods ; Genetic Vectors ; Horseradish Peroxidase ; genetics ; metabolism ; Humans ; Indoleacetic Acids ; metabolism ; Luciferases ; genetics ; metabolism ; Plasmids ; Prodrugs ; Promoter Regions, Genetic ; radiation effects ; Radiotherapy ; methods ; Recombinant Proteins ; genetics ; metabolism ; Telomerase ; genetics ; metabolism ; Transfection