MnSOD-PL Irradiation Protection of the Oral Cavity

描述（由申请人提供）：本项目旨在确定锰超氧化物歧化酶-质粒/脂质体（MnSOD-PL）基因治疗的肿瘤放射增敏机制，并优化保护口腔和口咽免受放射治疗（RT）诱导的粘膜炎的条件。 我们已经在小鼠模型中证明了MnSOD-PL的食管内、小肠内或口内给药保护正常组织免受单次或分次辐射诱导的损伤。 最近的数据表明，在鳞状细胞癌中MnSOD过表达通过消耗抗氧化剂，特别是谷胱甘肽（GSH），具有抗肿瘤作用。 第一个具体的目标是确定MnSOD介导的肿瘤放射增敏的机制，在细胞系或细胞团在体外，并在原位肿瘤在体内。 我们将确定向MnSOD-PL中加入抗肿瘤剂表皮生长因子受体酪氨酸激酶抑制剂（EGFR-TKI）ZD 1839（易瑞沙）是否有积极或消极的影响。 与正常组织相比，辐照（和/或易瑞沙处理）原位肿瘤中过氧亚硝酸盐和H2 O2产生的新真实的实时原位测量将用于直接定量MnSOD-PL肿瘤放射增敏期间的氧化还原变化。 在第二个具体目标中，使用用单一部分或部分RT（和/或易瑞沙）处理的正常小鼠，我们将确定MnSOD-PL的口内递送的最佳时间表和剂量，并定量RT诱导的损伤的几个客观参数，包括粘膜炎、舌溃疡、唾液排出、放射性骨坏死和纤维化。 第三个具体目标是确定静脉注射（I.五.）和/或口内MnSOD-PL分别在C3 H/HeNHsd和裸鼠的原位肿瘤的两种啮齿动物鳞状细胞癌模型中保护免受辐射粘膜炎所需的剂量，并确定对抗肿瘤反应的影响。 使用表位血凝素（HA）标记的MnSOD转基因，与口腔细胞相比，将定量原位肿瘤细胞中转基因表达的渗透深度，口腔细胞包括口底、下咽、口咽、移动的和舌根以及大唾液腺和小唾液腺。 我们将确定静脉注射MnSOD-PL是否通过照射加易瑞沙增强原位肿瘤杀伤，并将其与正常组织和肿瘤抗氧化剂水平定量相关。 该项目应验证使用辐射防护基因疗法来改善头颈癌患者的生活质量，并可能通过调节副作用促进辐射剂量的增加。

DESCRIPTION (provided by applicant): This project seeks to define the mechanism of tumor radiosensitization by manganese superoxide dismutase-plasmid/liposome (MnSOD-PL) gene therapy and optimize conditions for protection of the oral cavity and oropharynx from radiotherapy (RT)-induced mucositis. We have demonstrated in a murine model that intraesophageal, intratracheal or intraoral administration of MnSOD-PL protects normal tissues from single fraction or fractionated irradiation-induced injury. Recent data suggest that there is an antitumor effect of MnSOD overexpression in squamous cancers through depletion of antioxidants, specifically glutathione (GSH). The first specific aim seeks to define the mechanism of MnSOD mediated tumor radiosensitization in cell lines or cell pellets in vitro, and in orthotopic tumors in vivo. We will determine whether there is a positive or negative effect of adding the antitumor agent, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) ZD1839 (Iressa), to MnSOD-PL. Novel real time in situ measurement of peroxynitrite and H2O2production in irradiated (and/or Iressa-treated) orthotopic tumors compared to normal tissue will be used to quantitate directly redox changes during MnSOD-PL tumor radiosensitization. In the second specific aim, using normal mice treated with single fraction or fractionated RT (and/or Iressa), we will determine the optimal schedule and dose of intraoral delivery of MnSOD-PL and quantitate several objective parameters of RT-induced damage including mucositis, ulceration of the tongue, saliva output, osteoradionecrosis, and fibrosis. The third specific aim seeks to determine the schedule and dose of intravenous (I. V.) and/or intraoral MnSOD-PL required for protection from irradiation mucositis in two rodent squamous cell carcinoma models of orthotopic tumors in C3H/HeNHsd and nude mice, respectively, and determine effect on the antitumor response. Using an epitope hemagglutinin (HA)-tagged MnSOD transgene, the depth of penetration of transgene expression in cells of an orthotopic tumor compared to cells of the oral cavity, including the floor of the mouth, hypopharynx, oropharynx, mobile and base of the tongue, as well as major and minor salivary glands, will be quantitated. We will determine whether I.V. MnSOD-PL enhances orthotopic tumor killing by irradiation plus Iressa and relate this quantitatively to normal tissue and tumor antioxidant levels. This project should validate the use of radioprotective gene therapy for improving the quality of life in head and neck cancer patients, and may also facilitate irradiation dose escalation by modulating side effects.