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Objective To evaluate the antitumor effects of interferon (IFN)γ-endostatin based gene radiotherapy in a metastatic breast tumor model of mice, and to elucidate the possible mechanisms involved. Methods Murine mammary adenocarcinoma 4T1 cells transfected with pEgr-IFN-γ and pEgrendostatin plasmids were irradiated with 2-20 Gy of X-rays. IFN-γ and endostatin levels in the culture supernatants were measured. Female BALB/c mice were inoculated with 1 × 105 of 4T1 cells by mammary fat pad injection, and divided randomly into control, empty vector, gene therapy (pEgr-IFN-γ and pEgrendostatin), radiotherapy, and combined gene-radiotherapy groups. Tumor/body weight ratio, lung metastases, and survival of the tumor-bearing mice were observed. Splenic cytotoxic T-lymphocyte (CTL)and natural killer (NK) cell activity and intratumor microvessel density were also assessed. Results Irradiation significantly enhanced the section of IFN-γ and endostatin from the transfected 4T1 cells.Compared with gene therapy or radiotherapy alone, combined gene-radiotherapy resulted in the maximal attenuation in tumor growth rate, lung metastases and increased survival. The activities of CTL and NK cells were significantly enhanced and intratumor microvessel density reduced ( t = 2. 120-22.140, P ＜ 0.05 ).Conclusions IFN-γ-endostatin-based gene-radiotherapy could provide a potential antitumor effect in a murine metastatic breast tumor model, which may be related to IFN-γ-stimulated CTL and NK cell activation, and endostatin-induced antiangiogenic activity. Gene-radiotherapy could serve as a neoadjuvant therapy for the locally advanced breast cancer.
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Objective To explore the anti-tumor effects of Egr-IFNγ gene therapy combined with 125I-UdR radionuclide therapy in mice bearing H22 hepatocarcinoma and its mechanism. Methods The recombinant plasmid pcDNAEgr-IFNγ mixed with liposome was injected into tumor. 48 h later, 370 kBq 125I-UdR was injected into tumor. The tumor growth rates at different times were observed. After 3 d gene-radionuclide therapy, the concentration of IFNγ in cytoplasm of H22 cells and cytotoxic activities of splenic CTL of the mice in different groups were examined. Results The tumor growth rates of pcDNAEgr-IFNγ +125 I-UdR group were obviously lower than those of control group, 125I-UdR group and pcDNAEgr-1 +125I-UdR group 6-15 d after gene-radionuclide therapy. IFNγ protein was found in cytoplasm of H22 cells in PcDNAEgr-1FNγ+125I-UdR group after 3 d gene-radionuclide therapy. Cytotoxic activity of splenic CTL in pcDNAEgr-IFN7 + 125I-UdR group was significantly higher than that in the other groups (P<0.01). Conclusions The anti-tumor effects in vivo of pcDNAEgr-IFNγ gene therapy combined with 125I-UdR radionuclide therapy are better than those of 125I-UdR therapy.
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Objective:Egr-1 promoter was amplificated and Egr-PGL plasmid was constructed to study the expression of luciferase in transfected NIH3T3 cells after different doses of X-ray irradiation.Methods:Egr-1p was amlificated by PCR and inserted into PGL3-E vector.The expression of luciferase induced by X-ray was studied by counting the light of luciferase and stubstrate.Results:Egr-1 cDNA was obtained by PCR and was sequenced.The results indicated the sequence was almost correct.The Egr-1p was connected with PGL3 vector and was detected by electrophoresis.The constructs were used to transfect mouse NIH3T3 cells to characterize the regulatory function of Egr-1p after exposure to X-ray irradiation.The results indicate that the expression of luciferase of all groups irradiated is highter than that of 0 Gy group.The expression of groups irradiated is about 5-7.5 times greater than that of 0 Gy group.Conclusion:Egr-1pobtained can induce the expression of its downstream gene after different doses of X-ray irradiation.Low dose irradiation also can do it and it is may be more important in tumor gene therapy.
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Objective:In present study we observed the effect of whole body irradiation (WBI) with 75 mGy X-rays on the immune function of tumor-bearing mice.Methods:Lewis lung carcinoma cells were implanted into the right thigh muscle of C57BL/6J mice.Ten days after tumor implantation,the tumor-bearing mice were administrated with 75 mGy X-rays WBI,then the mice were sacrificed 18 h after irradiation to detect the immune parameters including the spontaneous proliferation of thymocytes,the proliferative response of splenocytes to ConA and LPS,the cytotoxic activities of specific cytotoxic lymphocytes (CTL) and natural killer cells (NK),as well as lymphokine activated killer cells (LAK) in spleen.The methods we used were 3H-TdR incorporation or release assay.Results:The immune parameters of exposed tumor-bearing mice were much higher than those of sham-irradiated tumor-bearing mice (P<0.01).Conclusion:These results suggested that low dose radiation (LDR) could enhance the immune function of tumor-bearing mice,which might be of practical significance in the prevention and therapy of cancer.
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Objective: To investigate the anti-tumor efficiency of B16 melanoma HACs in vivo and in vitro.Methods: Tris-HCI extract and Sephacryl S-200 gel filtration were applied to prepare B16 HACs, and the cytolokicity of specific CTL induced by HACs was tested. Results: The 41, 47 and 53 tube HACs obtained by gel filtration could decrease the tumor incidences, delay the time of tumor development and decrease the mortalitites of mice.Conclusion:60 ~ 97 kD HACs from B16 melanoma cytosol have the activites of inhibiting tumor and could be used in effective anti-tumor therapy.