MnSOD-PL Irradiation Protection of the Oral Cavity

描述(申请人提供)：该项目旨在明确锰超氧化物歧化酶-质粒/脂质体(MnSOD-PL)基因治疗肿瘤放射增敏的机制，并优化保护口腔和口咽免受放射(RT)诱导的粘膜炎的条件。我们已经在小鼠模型中证明，经食道、气管或口腔内给予MnSOD-PL可保护正常组织免受单一或分次照射所致的损伤。最近的数据表明，在鳞癌中，MnSOD的过度表达通过耗尽抗氧化剂，特别是谷胱甘肽(GSH)而发挥抗肿瘤作用。第一个具体目的是明确MnSOD介导的肿瘤放射增敏的机制，在体外细胞系或细胞颗粒，在体内的原位肿瘤。我们将确定在MnSOD-PL中加入抗肿瘤药物表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKI)ZD1839(易瑞沙)是否有积极或消极的影响。与正常组织相比，新的实时原位测量照射(和/或易瑞沙治疗)原位肿瘤中过氧亚硝酸盐和过氧化氢的产生将被用来直接定量MnSOD-PL肿瘤放射增敏过程中的氧化还原变化。在第二个特定目标中，我们将利用单次或分次RT(和/或Iressa)治疗的正常小鼠，确定口腔内注射MnSOD-PL的最佳时间和剂量，并对RT所致损伤的几个客观参数进行定量，包括粘膜炎、舌头溃疡、唾液输出、骨放射性坏死和纤维化。第三个具体目标是确定静脉注射的时间和剂量。和/或口腔内注射MnSOD-PL，分别在C3H/HeNHsd和裸鼠原位肿瘤的两种啮齿动物鳞状细胞癌模型上，观察其对放射粘膜炎的保护作用，并确定其对抗肿瘤反应的影响。使用血凝素(HA)标记的MnSOD转基因表位，将定量转基因表达在原位肿瘤细胞中相对于口腔细胞的渗透深度，包括口底、下咽、口咽、舌根和舌根，以及主要和次要唾液腺。我们将确定静脉注射MnSOD-PL是否能增强照射加易瑞沙对原位肿瘤的杀伤作用，并将其与正常组织和肿瘤抗氧化剂水平定量联系起来。该项目应该验证放射防护基因疗法在改善头颈部癌症患者生活质量方面的使用，并可能通过调节副作用来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.