Heat Induced Suicide Gene Therapy for H and N Surgery

描述（由申请人提供）：2004年将诊断约28，200例头颈部鳞状细胞癌（HNSCC）新发病例，估计发生7，200例死亡。显然，额外的局部治疗是必要的，以改善结果。为了确定额外的局部治疗的有效性，提出了一种使用修饰的病毒载体用于诊断和治疗目的的分子成像方法。该提案将使用分子成像来评估病毒载体给药后携带HNSCC异种移植物的小鼠中的转基因表达。热疗可增强体外电离辐射（IR）的细胞毒性作用。HNSCC因其解剖上的可及性而成为基因治疗和热疗策略的靶点。已在体外和体内证明，单纯疱疹病毒1型胸苷激酶（HSV 1-TK）与更昔洛韦（GCV）联合使用在TK基因转移后发挥细胞毒性作用。已经构建了一种突变型TK（mTK），其增强GCV的细胞毒性作用，并且可以使用正电子发射核苷类似物通过正电子发射断层扫描（PET）成像。因此，改善HNSCC的成像和治疗应该通过mTK的基因转移来实现。然而，与基因转移方法相关的问题之一是转基因的非靶向表达。在这方面，我们已经构建了一个腺病毒（AdHSmTK）的诱导型热休克70 b（HS）启动子控制下编码mTK。该载体仅允许在暴露于热后表达mTK。使用超声技术，我们可以提供集中的热量异种移植，平行于临床交付。具体目标是：（1）。表征AdHSmTK感染后HNSCC细胞中mTK表达的时间过程和水平，并确定暴露于GCV和IR后的细胞毒性; 2.）在暴露于热后，用microPET成像表征AdHSmTK感染后携带HNSCC异种移植物的裸鼠中mTK表达的时程和水平。我们假设，基因治疗与热疗和IR的组合将有一个更大的影响，无论是单独或组合的两种方式在体外，并使用分子成像优化系统在体内将导致一个合理的治疗方案结合这些方式在未来。

DESCRIPTION (provided by applicant): Approximately 28,200 new cases of head and neck squamous cell carcinoma (HNSCC) will be diagnosed in 2004 with an estimated 7,200 deaths occurring. Clearly, additional local therapy is warranted to improve outcome. To determine the effectiveness of additional local treatment, a molecular imaging approach is proposed using a modified viral vector for both diagnostic and treatment purposes. This proposal will use molecular imaging to evaluate transgene expression in mice bearing HNSCC xenografts following administration of the viral vector. It is well established that hyperthermia enhances the cytotoxic effects of external beam ionizing radiation (IR). HNSCC has become a target of gene therapy and hyperthermic intervention strategies due to its anatomic accessibility. The enzyme herpes simplex virus type 1 thymidine kinase (HSV1-TK) in combination with ganciclovir (GCV) has been shown in vitro and in vivo to exert a cytotoxic effect after gene transfer of TK. A mutant version of TK (mTK) that enhances the cytotoxic effects of GCV and can be imaged by positron-emission tomography (PET) using positron-emitting nuclesoside analogs has been constructed. Therefore, improved imaging and therapy of HNSCC should be accomplished by gene transfer of mTK. However, one of the problems associated with gene transfer approaches has been the non-target expression of transgene. In this regard, we have constructed an adenovirus (AdHSmTK) encoding mTK under control of the inducible heat shock 70b (HS) promoter. This vector will only allow expression of mTK after exposure to heat. Using ultrasound technology we can deliver focused heat to xenografts that parallels clinical delivery. The specific aims are: 1.) Characterize the time course and level of expression of mTK in HNSCC cells after infection with AdHSmTK and determine the cytotoxicity after exposure to GCV and IR; 2.) Characterize the time course and level of expression of mTK in nude mice bearing HNSCC xenografts after infection with AdHSmTK with microPET imaging following exposure to heat. We hypothesize that the combination of gene therapy with hyperthermia and IR will have a greater impact than either alone or combination of two of the modalities in vitro and that the use of molecular imaging to optimize the system in vivo will lead to a rational treatment protocol combining these modalities in the future.