Gamma-rays enhance rAAV-mediated transgene expression and cytocidal effect of AAV-HSVtk/ganciclovir on cancer cells.
Adeno-associated virus (AAV) vector has several unique properties suited for gene therapy applications. However, relatively low efficiency of transgene expression, which is mainly due to a limited second-strand synthesis from the single-stranded AAV genome, can be a problem in some applications that require potent gene expression such as antitumor applications. Recently, gamma-ray irradiation has been reported to enhance the second-strand synthesis of the AAV genome, and consequently transgene expression. We demonstrate here that an AAV vector harboring the herpes simplex virus type-1 thymidine kinase (HSVtk) is able to kill cancer cells more efficiently when used in combination with gamma-ray irradiation. A human maxillary sinus cancer cell line, NKO-1, was efficiently killed in combination with HSVtk transduction and ganciclovir (GCV), as expected. More importantly, gamma-ray irradiation of practical dosages augmented the cytocidal effect of the HSVtk/GCV system. Southern analysis indicated that gamma-rays enhanced the double-strand synthesis of the rAAV genome in NKO-1 cells. These findings suggest that the combination of rAAVtk/GCV suicide gene therapy with radiotherapy has synergistic effects in the treatment of cancers and may lead to a reduction of the potential toxicity of both rAAVtk/GCV and gamma-ray irradiation.
Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan.
T
T
Kanazawa
M
M
Urabe
H
H
Mizukami
T
T
Okada
A
A
Kume
H
H
Nishino
J
J
Monahan
K
K
Kitamura
K
K
Ichimura
K
K
Ozawa
D000998:Antiviral Agents / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000628:therapy* / Q000821:virology; D004277:DNA, Single-Stranded / Q000378:metabolism; D000229:Dependovirus / Q000235:genetics*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D015774:Ganciclovir / Q000494:pharmacology*; D015870:Gene Expression / Q000528:radiation effects; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D018259:Herpesvirus 1, Human / Q000201:enzymology*; D006801:Humans; D007763:Lac Operon; D008444:Maxillary Sinus Neoplasms / Q000628:therapy* / Q000821:virology; D011829:Radiation Dosage; D015996:Survival Rate; D013937:Thymidine Kinase / Q000008:administration & dosage / Q000235:genetics*; D019076:Transgenes; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000998:Antiviral Agents; D004277:DNA, Single-Stranded; D013937:Thymidine Kinase; D015774:Ganciclovir