Combinatory gene therapy with electrotransfer of midkine promoter-HSV-TK and interleukin-21.
We examined the effect of the combination of herpes simplex virus type1-thymidine kinase (HSV-TK)-suicide gene therapy and interleukin-21 (IL-21) immune gene therapy.


METHODS
To improve tumor specificity and the safety of gene therapy, we designed the suicide gene (HSV-TK) to be driven by midkine (MK) minimal promoter (MKp-TK). Plasmid DNA containing HSV-TK-suicide gene or IL-21 gene was injected into TE2 and Colon26 tumors developed in nude mice and electric pulses were then delivered.


RESULTS
Tumors transduced with the MKp-TK gene demonstrated increased sensitivity to ganciclovir (GCV) in vitro and in vivo. MK minimal promoter conferred efficient transcriptional activity to the HSV-TK-suicide gene and in vivo electroporation was an effective method for transducing the MKp-TK gene. IL-21-transduced tumors disappeared completely in syngeneic BALB/c mice. However, the tumors were not suppressed completely in T-cell-depleted nude mice, and antitumor effects were absent in NK-cell-depleted mice. These data suggest that IL-21 induces T- and NK-cell-dependent antitumor effects. Furthermore, the growth of IL-21-producing tumors subsequently transduced with MKp-TK by electroporation was significantly retarded compared with control groups.


CONCLUSIONS
Using the minimal promoter region of MK to drive the HSV-TK gene and in vivo electroporation to transduce IL-21 DNA into the tumors produced an efficient gene therapy with improved safety. To our knowledge, this is the first report of a combination gene therapy using HSV-TK/GCVand IL-21.
Hanari
Naoyuki
N
Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan.
Matsubara
Hisahiro
H
Hoshino
Isamu
I
Akutsu
Yasunori
Y
Nishimori
Takanori
T
Murakami
Kenataro
K
Sakata
Haruhito
H
Miyazawa
Yukimasa
Y
Ochiai
Takenori
T
D000230:Adenocarcinoma / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D000818:Animals; D003110:Colonic Neoplasms / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D003131:Combined Modality Therapy; D004247:DNA / Q000008:administration & dosage / Q000235:genetics; D018274:Electroporation / Q000379:methods; D004938:Esophageal Neoplasms / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D015774:Ganciclovir / Q000493:pharmacokinetics / Q000494:pharmacology; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007378:Interleukins / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011401:Promoter Regions, Genetic; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D014161:Transduction, Genetic / Q000379:methods; D000098546:Interleukin-21
D007378:Interleukins; D004247:DNA; D013937:Thymidine Kinase; D000098546:Interleukin-21; D015774:Ganciclovir