RESUMO
Heterologous expression of the Drosophila melanogaster multi-substrate deoxyribonucleoside kinase (Dm-dNK) increases the sensitivity of cancer cells to several cytotoxic nucleoside analogs. Thus, it may be used as a suicide gene in combined gene/chemotherapy treatment of cancer. To further characterize this potential suicide gene, we constructed two retroviral vectors that enabled the expression of Dm-dNK in cancer cells. One vector harbored the wildtype enzyme that localized to the nucleus. The other vector harbored a mitochondrial localized mutant enzyme that was constructed by deleting the nuclear localization signal and fusing it to a mitochondrial import signal of cytochrome c oxidase. A thymidine kinase-deficient osteosarcoma cell line was transduced with the recombinant viruses. The sensitivity and bystander cell killing in the presence of pyrimidine nucleoside analogs (E)-5-(2-bromovinyl)2'deoxyuridine and 1-ß-D-arabinofuranosylthymine were investigated. Tanshinone IIA is a constituent of Danshen; a traditional Chinese medicine used in the treatment of cardiovascular diseases. This study also looked at the influence of Tanshinone IIA on the bystander effect and the underlying mechanisms. We showed that sensitivity of the osteosarcoma cell line to the nucleoside analogs and the efficiency of bystander cell killing were independent of the subcellular localization of Dm-dNK. The enhanced effect of tanshinone IIA on the bystander effect was related to the increased expression of Cx43 and Cx26.
Assuntos
Abietanos/administração & dosagem , Terapia Genética , Osteossarcoma/tratamento farmacológico , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Animais , Efeito Espectador , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Conexina 26 , Conexinas , Desoxiuridina/administração & dosagem , Desoxiuridina/análogos & derivados , Drosophila melanogaster/enzimologia , Drosophila melanogaster/genética , Galactose/administração & dosagem , Galactose/análogos & derivados , Vetores Genéticos , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Sinais de Localização Nuclear/genética , Osteossarcoma/genética , Osteossarcoma/patologia , Fosfotransferases (Aceptor do Grupo Álcool)/biossíntese , Retroviridae/genética , Timina/administração & dosagem , Timina/análogos & derivadosRESUMO
Survivin has been shown to be highly expressed in ovarian cancers, but not normal ovarian tissue, which makes it an attractive target for ovarian cancer treatment. Emodin is a traditional Chinese medicine that has been found to inhibit proliferation and induce apoptosis in ovarian cancer cells. Thus, in our study, we combined survivin-targeted shRNA (sur-shRNA) with emodin and tested the effects of this combination on ovarian cancer cells to identify more effective therapeutics against ovarian cancer. A sur-shRNA plasmid was constructed and transfected into the ovarian cancer cell lines SKOV3 and HO8910, and the cells were cultured for 24 h. The cells were then treated with emodin for specific time periods and assessed for viability and apoptosis using the MTT assay and flow cytometry, respectively. Cell invasion was also measured using a Matrigel invasion assay. The shRNA specific for survivin effectively reduced the expression of survivin at the mRNA and protein levels in SKOV3 and HO8910 cells. Both emodin and shRNA-mediated knockdown of survivin significantly inhibited cell proliferation, induced apoptosis, and suppressed invasion in SKOV3 and HO8910 cells (P<0.05). Moreover, the combination of the agents significantly enhanced these effects (P<0.05). We found that the combination of sur-shRNA and emodin could be effective in the treatment of ovarian cancer.