Study of the suicide gene therapy using HSVtk gene and GCV for oral cancer

基因治疗为癌症治疗提供了新的途径。本研究的目的是验证单纯疱疹病毒胸苷激酶（HSVtk）基因联合更昔洛韦（GCV）自杀基因治疗口腔癌的可行性。使用了4个人类口腔鳞状细胞癌细胞系。为了评估转导效率，每个细胞系在体外用含有β-半乳糖苷酶基因的腺病毒载体（Ad）或腺相关病毒载体（AAV）转导。转导24小时后，几乎100%的细胞在感染多重数（multiplicity of infection， MOI）为10的情况下被转导，而在Ad中，MOI为1的情况下，转导率从10%提高到30%。在MOI为10000时，AAV的转导效率接近100%，在MOI为1000时，转导效率为40% ~ 50%。接下来，用含有HSVtk基因的Ad或AAV转导每个细胞系，随后给药GCV以评估自杀基因治疗的效果。随后给药GCV导致肿瘤细胞完全死亡。含HSVtk基因的Ad或AAV注射后，经胃内注射GCV可显著抑制口腔鳞状细胞癌SAS移植裸鼠的肿瘤生长。这些结果表明，用HSVtk和GCV进行自杀基因治疗是治疗口腔癌的有效策略。

Gene therapy offers the possibility of new approach to cancer treatment. The purpose of this study was to test the feasibility of suicide gene therapy using herpes simplex virus thymidine kinase (HSVtk) gene and ganciclovir (GCV) for oral cancer. Four human oral squamous cell carcinoma sell lines were used. To evaluate transduction efficiency, each cell line was transduced in vitro with an adenovirus vector (Ad) or adeno-associated virus vector (AAV) containing the β-galactosidase gene. By 24 hours after transduction, nearly 100% of the cells were transduced at a multiplicity of infection (MOI) of 10, and from 10 to 30% at a MOI of 1 in Ad. Transduction efficiency in AAV was nearly 100% at a MOI of 10000, and from 40 to 50% at a MOI of 1000. Next, each cell line was transduced with an Ad or AAV containing the HSVtk gene, and subsequent administration of GCV for the assessment of suicide gene therapy. Subsequent administration of GCV resulted in complete tumor cell death. Ad or AAV containing the HSVtk gene injection followed by intraperiotoneal GCV administration inhibited remarkably tumor growth in the nude mice to which oral squamous cell carcinoma cell SAS was transplanted SCID mouse. These results suggest that suicide gene therapy with HSVtk and GCV has revealed an effective treatment strategy for the oral cancer.