A novel fusion suicide gene yeast CDglyTK plays a role in radio-gene therapy of nasopharyngeal carcinoma.
To investigate a novel suicide gene for nasopharyngeal carcinoma (NPC) therapy, the yCDglyTK gene was constructed by fusing yeast cytosine deaminase (CD) and herpes simplex type 1 thymidine kinase. The expression of the yCDglyTK gene was detected by RT-PCR and Western blotting, and its bioactivity was demonstrated by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. An animal study was carried out in which BALB/C nude mice bearing yCDglyTK gene-modified tumors were treated with prodrugs and radiation. Our results revealed that the yCDglyTK gene could be expressed in CNE-2 cells in vitro. In MTT analysis, at the transfection rate of 10%, 66% cells were killed. The synergistic effect of CD and TK showed 91% of yCDglyTK-transfected cells were killed with the treatment of 5-fluorocytosine (5-FC) alone, 60% killed with ganciclovir (GCV) alone, and 75% killed with 5-FC and GCV together. In vivo, the tumor volume in all of the four prodrugs and/or radiation-treated groups were significantly different from that in the PBS-controlled group (P<.01); also yCDglyTK+prodrug+radiation group was different from the other three groups (P<.05). Our findings suggested there was a synergistic antitumor effect when combining suicide gene therapy and radiation, and yCDglyTK has potent antitumor efficacy and may be a candidate suicide gene for cancer therapy.
Xia
Kun
K
National Lab. of Medical Genetics of China, Central South University, Changsha, Hunan, People's Republic of China.
Liang
Desheng
D
Tang
Aifa
A
Feng
Yong
Y
Zhang
Junyi
J
Pan
Qian
Q
Long
Zhigao
Z
Dai
Heping
H
Cai
Fang
F
Wu
Lingqian
L
Zhao
Suping
S
Chen
Zhuchu
Z
Xia
Jiahui
J
D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002277:Carcinoma / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D003131:Combined Modality Therapy / Q000379:methods; D043525:Cytosine Deaminase / Q000235:genetics; D005437:Flucytosine / Q000627:therapeutic use; D015774:Ganciclovir / Q000627:therapeutic use; D005800:Genes, Fungal / Q000235:genetics*; D041722:Genes, Transgenic, Suicide / Q000235:genetics*; D015316:Genetic Therapy; D018259:Herpesvirus 1, Human / Q000235:genetics; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy / Q000532:radiotherapy / Q000628:therapy*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D013937:Thymidine Kinase / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D015003:Yeasts
D013778:Tetrazolium Salts; D013844:Thiazoles; D005437:Flucytosine; D013937:Thymidine Kinase; D043525:Cytosine Deaminase; C022616:thiazolyl blue; D015774:Ganciclovir