ABSTRACT
Objective To investigate the effect of E1A gene on the radiosensitivity of human nasopharyngeal carcinoma cells and its possible mechanism. Methods The E1A gene was transfected into nasopharyngeal carcinoma CNE-2R cells by adenovirus vector. The expression of E1A gene was detected by RT-PCR. Untransfected CNE-2R cells(PBS group)and CNE-2R cells transfected with empty vector Ad-β-gal(Ad-β-gal group)and E1A(Ad-E1A group)were given 0 Gy,2 Gy,4 Gy,6 Gy,8 Gy 6 MV X-ray irradiation. The changes in radiosensitivity of CNE-2R cells were determined by colony-forming assay. Flow cytometry was used to analyze cell apoptosis in each group. The expression of NF-κB, CK2α, Bcl-2, and cleaved caspase-3 was measured by Western blot. Results RT-PCR confirmed that the E1A gene was transfected into CNE-2R cells and stably expressed. The Ad-E1A group had a significantly lower plating efficiency than the PBS group and the Ad-β-gal group(P<0.05). The Ad-E1A group had significantly lower cell survival rate at 2 Gy irradiation than the PBS group and the Ad-β-gal group(0.217 vs. 0.602, P<0.05;0.217 vs. 0.585, P<0.05). The Ad-E1A group had a significantly higher α/β value than the PBS group and the Ad-β-gal group(24.680 vs. 5.268, P<0.05;24.680 vs. 5.132, P<0.05). Flow cytometry results showed that irradiation alone could promote the apoptosis of CNE-2R cells,when combined with E1A gene,the apoptosis rate was significantly increased(P<0.05). Western blot results showed that E1A gene down-regulated the expression of NF-κB/p65,CK2α,and Bcl-2 and up-regulated the expression of cleaved caspase-3. Conclusions E1A gene can enhance the radiosensitivity of nasopharyngeal carcinoma cells by inhibiting the expression of CK2 to block the NF-κB signaling pathway and promoting cell apoptosis.
ABSTRACT
Objective To study the effect of E1A gene on the radiosensitivity of nasopharyngeal carcinoma (NPC) cells and its mechanism. Methods Ad-E1A gene was transfected into human NPC cells (CNE2), then the positive clones (CNE2-Ad-E1A) were identified by RT-PCR. CNE2 cells, CNE2 cells transfected with Ad-β-gal (CNE2-Ad-β-gal) and CNE2-Ad-E1A cells were irradiated with 0 Gy,2 Gy,4 Gy,6 Gy and 8 Gy respectively using 6 MV X-ray. Clone forming assays were carried out, cell survival curves were drawn and the sensitivity enhancing ratio (SER) was calculated. The redistributions of cell cy-cle were analyzed by flow cytometry. RT-PCR was used to detect the expression of wtp53. Results RT-PCR confirmed that E1A gene had been integTated into positively transfected cells and stably expressed. Cell survival curves showed that the SER of D0,Dq and SF_2 value was 1.37, 1.95 and 1.46 in CNE2-Ad-E1A cells. The D_0,D_q and SF_2 value was 1.57 Gy,1.82 Gy, 0.89 in CNE-2 cells and 1.53 Gy,1.78 Gy,0.82 in CNE2-Ad-β-gal cells, respectively. The G_2/M arrest was shown in CNE2-Ad-E1A cells. Moreover, the expression of wtp53 gene was markedly enhanced in Ad-E1A-CNE2 cells. Conclusions E1A gene can ef-fectively enhance the radiosensitivity of human NPC cells, which may be associated the enhancement of wt-p53 expression and G_2/M arrest.
ABSTRACT
Objective To construct a new conditionally replicative adenovirus (CRAds) targeting carcinoembryonic antigen (CEA) positive colorectal cancer cells. Methods The DNA fragment of the CEA gene promoter was amplified through PCR and cloned into the vector carrying fusion reporter gene EGFP-Luc to construct expression plasmid pCEA-EGFPLuc. The constructed plasmid pCEA-EGFPLuc was transfected into CEA positive and negative cells by liposome. The activity of CEA gene promoter was evaluated by detecting the expression of EGFP and luciferase activity. The conditionally replicative adenovirus Ad.CEA-E1A/CMV-TK carrying suicide gene HSVtk was constructed, in which the E1A gene was controlled under CEA promoter. CEA positive(Lovo and SW620)and negative tumor cells(HeLa) were infected with Ad.CEA-E1A/ CMV-TK. The selective cytotoxicity of Ad.CEA-E1A/CMV-TK and the synergistic effect of the virus with GCV in CEA positive tumor cells were evaluated by the expression of E1A, cytopathic effect and cell survival rate. Results CEA promoter possesses a good specificity as well as high activity. The expression of E1A only presented in CEA positive tumor cells. After infection with Ad. CEA-E1A/CMV-TK, the cell survival rates of Lovo and SW620 were (36.72±2.49)% and (39.82±4.76)%, respectively, significantly lower than that of Hela[(87.44±2.76)%1 (P<0.01). When combined with GCV, Ad.CEA-E1A/CMV-TK had better oncolytic effect on Lovo and SW620 cells, with cell survival rates of (17.26±3.65) % and (23.93±5.40) %, respectively, significantly lower than those without GCV[(36.72±2.49) % and (39.82±4.76) %, respectively] (P<0.01). Conclusion Ad. CEA-E1A/CMV-TK under the control of CEA promoter has selective cytotoxic effect on CEA positive colorectal cancer cells, and the effect can be enhanced when combined with GCV.
ABSTRACT
Objective:To study the inhibitory effect of E1A gene on the growth of tumors in nude mice implanted with nasopharygeal carcinoma CNE2 cells and its promotion effect on the racliosensitivity of CNE2-implanted tumors, and to investigate the related mechanism. Methods: E1A gene was transfected into CNE2 cells using adenovirus system, and sta-ble E1A positive clones were established. The inhibitory effect of E1A on tumor formation-ability of CNE2 cells was ob-served in nude mice. The efficacy of E1A gene therapy with or without radiotherapy against CNE2 cell-implanted tumors was evaluated. The effect of E1A gene therapy on the expression of P53 was detected by RT-PCR. Results: CNE2 cells stably transfected with E1A gene (CNE2-Ad-E1A) were successfully established. The tumor formation time was later and tumor size was smaller in CNE2-Ad-E1A cell-implanted mice compared with those in CNE2 cell- and CNE2-Ad-β-gal cell-implanted mice (CNE2 cells stably transfected with Ad-β-gal). Radiotherapy, E1A gene therapy and E1A gene + radio-therapy all suppressed the growth of implanted tumors, with the tumor suppression rates being (60.32±5.34) %, (70.53±6.12) %, and (97.15±4.87) % , respectively. E1A gene therapy significantly increased the expression of P53 gene in tumor tissues. Conclusion: E1A can inhibit the growth of tumors in mice implanted with nasopharygeal carcinoma cells, and enhance its sensitivity to radiotherapy, which may be related to the increased expression of P53 gene in tumor tissues.
ABSTRACT
Objective:To study the inhibitory effect of E1A gene on the growth of tumors in nude mice implanted with nasopharygeal carcinoma CNE2 cells and its promotion effect on the radiosensitivity of CNE2-implanted tumors,and to investigate the related mechanism.Methods: E1A gene was transfected into CNE2 cells using adenovirus system,and stable E1A positive clones were established.The inhibitory effect of E1A on tumor formation-ability of CNE2 cells was observed in nude mice.The efficacy of E1A gene therapy with or without radiotherapy against CNE2 cell-implanted tumors was evaluated.The effect of E1A gene therapy on the expression of P53 was detected by RT-PCR.Results: CNE2 cells stably transfected with E1A gene(CNE2-Ad-E1A)were successfully established.The tumor formation time was later and tumor size was smaller in CNE2-Ad-E1A cell-implanted mice compared with those in CNE2 cell-and CNE2-Ad-?-gal cell-implanted mice(CNE2 cells stably transfected with Ad-?-gal).Radiotherapy,E1A gene therapy and E1A gene+radiotherapy all suppressed the growth of implanted tumors,with the tumor suppression rates being(60.32?5.34)%,(70.53?6.12)%,and(97.15?4.87)%,respectively.E1A gene therapy significantly increased the expression of P53 gene in tumor tissues.Conclusion: E1A can inhibit the growth of tumors in mice implanted with nasopharygeal carcinoma cells,and enhance its sensitivity to radiotherapy,which may be related to the increased expression of P53 gene in tumor tissues.
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Objective:To explore the expression of intercellular adhesion molecule-1(ICAM-1 )induced by cigarette smoking extract(CSE) as well as the influence of the adenovirus E1A gene in pulmonary epithelial cells.Methods:A549 cells were transfected with a plasmid carrying the adenovirus E1A gene and stable trasfectants expressing E1A protein were selected. The cells were tested for the expression of ICAM-1 after stimulation with different concentrations of CSE.Results:ICAM-1expression was increased in A549 markedly with CSE stimulation,and the higher CSE concentration were,the more expression of ICMA-1 was observed. As compared with parental cells or cells transfected with control plasmid, ICAM-1 expression was markedly increased with stimulation of different concentrations of CSE in E1A-positive A549 cells.Conclusion:CSE exposure induces the surface expression of ICAM-1 and adenovirus E1A gene can markedly increase ICAM-1 expression induced by CSE in pulmonary epithelial cells, which suggest that latent adenovirus infection may amplify the inflammation process present in airways of smokers.