Heat Induced Suicide Gene Therapy for H and N Cancer

描述(申请人提供)：2004年将诊断出大约28,200例新的头颈部鳞状细胞癌(HNSCC)，估计有7,200例死亡。显然，额外的局部治疗是有必要的，以改善结果。为了确定额外局部治疗的有效性，提出了一种分子成像方法，使用修改后的病毒载体进行诊断和治疗。这项建议将使用分子成像来评估在注射病毒载体后携带HNSCC异种移植瘤的小鼠的转基因表达。众所周知，热疗可增强外束电离辐射(IR)的细胞毒性效应。由于其解剖可及性，HNSCC已成为基因治疗和热疗干预策略的靶点。单纯疱疹病毒1型胸苷激酶(HSV1-TK)与更昔洛韦(GCV)联合应用，在体内外均能发挥TK基因转移后的细胞毒作用。TK(MTK)的突变版本已被构建，它增强了GCV的细胞毒性效应，并可通过正电子发射核苷类似物的正电子发射断层扫描(PET)进行成像。因此，改善HNSCC的影像和治疗应通过MTK的基因转移来完成。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，我们构建了在可诱导热休克70b(HS)启动子控制下编码MTK的腺病毒(AdHSmTK)。该载体只允许MTK在受热后表达。使用超声波技术，我们可以向异种移植物输送与临床输送平行的聚焦热能。具体目标是：1.方法：1.鉴定AdHSmTK感染HNSCC细胞后MTK表达的时程和水平，并检测GCV和IR对HNSCC细胞的细胞毒作用。)用热暴露后的microPET成像技术研究携带HNSCC裸鼠移植瘤感染AdHSmTK后MTK表达的时程和水平。我们假设，在体外，基因治疗与热疗和IR的结合将比单独或两种模式的组合产生更大的影响，使用分子成像来优化体内的系统将导致未来结合这些模式的合理治疗方案。

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.