TK gene combined with mIL-2 and mGM-CSF genes in treatment of gastric cancer.
OBJECTIVE
Cancer gene therapy has received more and more attentions in the recent decade. Various systems of gene therapy for cancer have been developed. One of the most promising choices is the suicide gene. The product of thymidine kinase (TK) gene can convert ganciclovir (GCV) to phosphorylated GCV, which inhibits the synthesis of cell DNA, and then induces the cells to death. Cytokines play an important role in anti-tumor immunity. This experiment was designed to combine the TK gene and mIL-2/mGM-CSF genes to treat gastric cancer, and was expected to produce a marked anti-tumor effect.


METHODS
TK gene was constructed into the retroviral vector pLxSN, and the mIL-2 and mGM-CSF genes were inserted into the eukaryotic expressing vector pIRES. The gastric cancer cells were transfected by retroviral serum that was harvested from the package cells. In vitro study, the transfected gastric cancer cells were maintained in the GCV- contained medium, to assay the cell killing effect and bystander effect. In vivo experiment, retroviral serum and cytokines plasmid were transfected into tumor-bearing mice, to observe the changes of tumor volumes and survival of the mice.


RESULTS
In vitro experiment, 20 % TK gene transduced cells could cause 70-80 % of total cells to death. In vivo results showed that there was no treatment effect in control group and TK/GCV could inhibit the tumor growth. The strongest anti-tumor effect was shown in TK+mIL-2+mGM-CSF group. The pathologic examination showed necrosis of the cancer in the treated groups.


CONCLUSIONS
TK/GCV can kill tumor cells and inhibit the tumor growth in vivo. IL-2 and GM-CSF strongly enhance the anti-tumor effect. Through the retrovirus and liposome methods, the suicide gene and cytokine genes are all expressed in the tissues.
Guo
Shan-Yu
SY
Department of Surgery, the Affiliated Shanghai Ninth People's Hospital, Shanghai Second Medical University, Shanghai 200011, China. doc.g@163.com
Gu
Qin-Long
QL
Zhu
Zheng-Gang
ZG
Hong
He-Qun
HQ
Lin
Yan-Zhen
YZ
D000818:Animals; D015316:Genetic Therapy; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics*; D007376:Interleukin-2 / Q000235:genetics*; D051379:Mice; D013274:Stomach Neoplasms / Q000628:therapy*; D013937:Thymidine Kinase / Q000235:genetics*; D014407:Tumor Cells, Cultured
D007376:Interleukin-2; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013937:Thymidine Kinase