IL-12 Gene Therapy for Metastatic Osteosarcoma

描述（由申请人提供）： 骨肉瘤是最常见的原发性骨恶性肿瘤，通常出现在青春期和青年期，此时长骨正在快速生长。 在诊断骨肉瘤的儿童经常有肺部微转移，而胸部X线或CT无法发现。 尽管有积极的化疗和手术干预，30-40%的患者会复发肺转移。 2年无病生存率在过去15年中没有显著变化。 需要新的药物和新的方法来提高这些儿童的存活率。 使用人骨肉瘤肺转移的裸鼠模型，用表达白细胞介素-12的腺病毒载体鼻内治疗导致小鼠肺转移的数量和大小急剧减少。 该疗法诱导的抗肿瘤免疫主要由自然杀伤细胞和抗血管生成机制介导。 IL-12具有两种主要的抗肿瘤活性，即免疫依赖性和免疫非依赖性。 裸鼠模型可用于确定免疫非依赖性机制。 最近，原位，同基因小鼠骨肉瘤模型的开发。 骨内注射鼠肿瘤细胞后，在注射部位的骨中形成肿瘤。 这些小鼠继续自发地发生肺转移。 该模型具有完整的免疫系统，将允许确定IL-12的抗肿瘤活性的免疫依赖性机制。 将追求四个具体目标：1）确定施用Ad.mIL-12后浸润肿瘤细胞的细胞的身份和时间。 2)确定IL-12是否激活NK细胞以根除肺骨肉瘤转移。 3)为了确定IL-12（干扰素的主要诱导剂？）在刺激巨噬细胞和树突活性中起作用。 4)确定T细胞在IL-12基因治疗的抗肿瘤活性中的作用。 这些研究的成功完成将导致更好地理解免疫系统的作用（当用IL-12和T细胞受体激动剂激活时）。

DESCRIPTION (provided by applicant): Osteosarcoma is the most common primary bone malignancy that usually presents during the adolescent and young adult years when the long bones are undergoing rapid growth. At diagnosis children with osteosarcoma frequently have pulmonary micrometastases that are not detected by chest X ray or CT. Despite aggressive chemotherapy and surgical intervention, 30-40% of patients will relapse with pulmonary metastases. The 2-year disease-free survival has not changed significantly in the past 15 years. New agents and novel approaches are needed to increase the survival rate in these children. Using a nude mouse model with human osteosarcoma lung metastases, intranasal therapy with an adenoviral vector expressing interleukin-12 resulted in a dramatic decrease in the number and size of pulmonary metastases in mice. The antitumor immunity induced by this therapy is mediated primary by natural killer cells and antiangiogenic mechanisms. IL-12 has two main anti-tumor activities that are immune-dependent and immune-independent. The nude mouse model is useful for determining the immune-independent mechanisms. Recently an orthotopic, syngenic murine osteosarcoma model was developed. After the intraosseous injection of murine tumor cells, a tumor forms in bone at the site of injection. These mice go on to spontaneously develop pulmonary metastases. This model, with an intact immune system, will allow the immune-dependent mechanisms of IL-12's antitumor activity to be determined. Four specific aims will be pursued: 1) To determine the identity and timing of cells that infiltrate tumor cells after the administration of Ad.mIL-12. 2) To determine if IL-12 activates NK cells to eradicate pulmonary osteosarcoma metastases. 3) To determine the role IL-12 (the primary inducer of interferon-?) plays in stimulating macrophage and dendritic activity. 4) To determine the role T cells play in the anti-tumor activity of gene therapy with IL-12. Successful completion of these studies will result in a better understanding of the role the immune system (when activated with IL-12 and T cells receptor agonists).