IL-12 Gene Therapy for Metastatic Osteosarcoma

描述(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壮年，此时长骨正在快速生长。在诊断时，患有骨肉瘤的儿童通常有胸部X光或CT无法发现的肺部微转移。尽管有积极的化疗和手术干预，30%-40%的患者仍会复发并出现肺转移。两年无瘤生存期在过去15年中无明显变化。需要新的药物和新的方法来提高这些儿童的存活率。在人骨肉瘤肺转移裸鼠模型上，表达白细胞介素12的腺病毒载体鼻腔治疗可显著减少小鼠肺转移瘤的数目和大小。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有两种主要的抗肿瘤活性，一种是免疫依赖的，另一种是非免疫依赖的。裸鼠模型可用于确定免疫非依赖性机制。最近建立了一种原位、同基因的小鼠骨肉瘤模型。小鼠肿瘤细胞骨内注射后，在注射部位的骨骼中形成肿瘤。这些小鼠继续自发地发展成肺转移瘤。该模型具有完整的免疫系统，可用于确定IL-12‘S抗肿瘤活性的免疫依赖机制。将追求四个具体目标：1)确定在给予Ad.mIL-12后渗透到肿瘤细胞的细胞的身份和时间。2)探讨IL-12是否能激活NK细胞以清除肺性骨肉瘤转移。3)确定IL-12(干扰素的主要诱导者)的作用。在刺激巨噬细胞和树突状细胞活性方面发挥作用。4)探讨T细胞在IL-12基因治疗抗肿瘤活性中的作用。这些研究的成功完成将有助于更好地理解免疫系统的作用(当被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).