[Anti-tumor effect of pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in tumor-bearing nude mice].
OBJECTIVE
To investigate the optimal doses of X-ray irradiation and plasmid injection in the anti-tumor effect of the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in vivo.


METHODS
We observed the anti-tumor effect of the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy with different doses of X-ray irradiation (2, 10, 20 Gy) and plasmid injection (10, 20, 30 microg) in nude mice with JF-305 pancreatic carcinoma, and detected the expression of p16 in tumor by RT-PCR.


RESULTS
The tumor growth rate of the nude mice irradiated locally with 20 Gy X-rays after the plasmid injection was significantly lower (P < 0.05 ) than that of the nude mice irradiated locally with 2 Gy or 10 Gy X-ray 3 days after the irradiation. The tumor growth rate of the nude mice injected locally with 20 microg or 30 microg plasmid was significantly lower (P <0.05 ) than that of the nude mice injected locally with 10 microg plasmid. Both pcDNA3. 1-Egr. 1p-p16 group and pcDNA3. 1-Egr. 1p-p16 +20 Gy group had p16 mRNA expression, but the mRNA level of pcDNA3. 1-Egr. 1p-p16 +20 Gy group was higher than that of pcD- NA3. 1-Egr. 1p-p16 group.


CONCLUSIONS
In the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in vivo the optimal dose of X-ray irradiation was 20 Gy and the optimal dose of plasmid injection was 20 microg. The anti-tumor effect of pcDNA3. 1-Egr. 1p-p16 combined with radiotherapy is better than that of radiotherapy or gene therapy alone, which may be related with the enhanced p16 expression in tumor after the irradiation.
Ma
Hong-bing
HB
Department of Oncology, Second Hospital of Xian Jiaotong University, Xian 710004.
Wang
Xi-jing
XJ
Hu
Hai-tao
HT
Di
Zheng-li
ZL
Xia
Hui
H
Wang
Zheng
Z
Li
Cheng
C
Han
Zhi-kai
ZK
Ma
Jie
J
Wu
Cong-mei
CM
D000818:Animals; D003131:Combined Modality Therapy; D004247:DNA / Q000235:genetics*; D051766:Early Growth Response Protein 1 / Q000235:genetics*; D005260:Female; D019942:Genes, p16; D015316:Genetic Therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000532:radiotherapy* / Q000628:therapy; D011994:Recombinant Proteins / Q000378:metabolism
D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D011994:Recombinant Proteins; D004247:DNA