Anti-tumor effect of pEgr-IFNgamma gene-radiotherapy in B16 melanoma-bearing mice.
OBJECTIVE
To construct a pEgr-IFNgamma plasmid and to investigate its expression properties of interferon-gamma (INF-gamma) induced by irradiation and the effect of gene-radiotherapy on the growth of melanoma.


METHODS
A recombined plasmid, pEgr-IFNgamma, was constructed and transfected into B16 cell line with lipofectamine. The expression properties of pEgr-IFNgamma were investigated by ELISA. Then, a B16 melanoma-bearing model was established in mice, and the plasmid was injected into the tumor tissue. The tumor received 20 Gy X-ray irradiation 36 h after injection, and IFN-gamma expression was detected from the tumor tissue. A tumor growth curve at different time points was determined.


RESULTS
The eukaryotic expression vector, pEgr-IFNgamma, was successfully constructed and transfected into B16 cells. IFN-gamma expression was significantly increased in transfected cells after X-ray irradiation in comparison with 0 Gy group (77.73-94.60 pg/mL, P<0.05-0.001), and was significantly higher at 4 h and 6 h than that of control group after 2 Gy X-ray irradiation (78.90-90.00 pg/mL, P<0.01-0.001). When the transfected cells were given 2 Gy irradiation 5 times at an interval of 24 h, IFN-gamma expression decreased in a time-dependent manner. From d 3 to d 15 after IFNgamma gene-radiotherapy, the tumor growth was significantly slower than that after irradiation or gene therapy alone.


CONCLUSIONS
The anti-tumor effect of pEgr-IFNgamma gene-radiotherapy is better than that of genetherapy or radiotherapy alone for melanoma. These results may establish an important experimental basis for gene-radiotherapy of cancer.
Wu
Cong-Mei
CM
Research Center of Reproductive Medicine, Shantou University Medical College (SUMC), shantou 515041, Guangdong Province, China. cmwu@stu.edu.cn
Li
Xiu-Yi
XY
Huang
Tian-Hua
TH
D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D004268:DNA-Binding Proteins / Q000235:genetics; D051766:Early Growth Response Protein 1; D015316:Genetic Therapy; D017874:Immediate-Early Proteins / Q000235:genetics; D007371:Interferon-gamma / Q000627:therapeutic use*; D008546:Melanoma, Experimental / Q000276:immunology / Q000532:radiotherapy / Q000628:therapy*; D051379:Mice; D008815:Mice, Inbred Strains; D010957:Plasmids; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics
D000998:Antiviral Agents; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D007371:Interferon-gamma