Collins Sara A, Buhles Alexandra, Scallan Martina F, Harrison Patrick T, O'Hanlon Deirdre M, O'Sullivan Gerald C, Tangney Mark
Cork Cancer Research Centre, Mercy University Hospital and Leslie C, Quick Jnr, Laboratory, University College Cork, Cork, Ireland.
Genet Vaccines Ther. 2010 Dec 20;8:8. doi: 10.1186/1479-0556-8-8.
Many strategies have been adopted to unleash the potential of gene therapy for cancer, involving a wide range of therapeutic genes delivered by various methods. Immune therapy has become one of the major strategies adopted for cancer gene therapy and seeks to stimulate the immune system to target tumour antigens. In this study, the feasibility of AAV2 mediated immunotherapy of growing tumours was examined, in isolation and combined with anti-angiogenic therapy.
Immune-competent Balb/C or C57 mice bearing subcutaneous JBS fibrosarcoma or Lewis Lung Carcinoma (LLC) tumour xenografts respectively were treated by intra-tumoural administration of AAV2 vector encoding the immune up-regulating cytokine granulocyte macrophage-colony stimulating factor (GM-CSF) and the co-stimulatory molecule B7-1 to subcutaneous tumours, either alone or in combination with intra-muscular (IM) delivery of AAV2 vector encoding Nk4 14 days prior to tumour induction. Tumour growth and survival was monitored for all animals. Cured animals were re-challenged with tumourigenic doses of the original tumour type. In vivo cytotoxicity assays were used to investigate establishment of cell-mediated responses in treated animals.
AAV2-mediated GM-CSF, B7-1 treatment resulted in a significant reduction in tumour growth and an increase in survival in both tumour models. Cured animals were resistant to re-challenge, and induction of T cell mediated anti-tumour responses were demonstrated. Adoptive transfer of splenocytes to naïve animals prevented tumour establishment. Systemic production of Nk4 induced by intra-muscular (IM) delivery of Nk4 significantly reduced subcutaneous tumour growth. However, combination of Nk4 treatment with GM-CSF, B7-1 therapy reduced the efficacy of the immune therapy.
Overall, this study demonstrates the potential for in vivo AAV2 mediated immune gene therapy, and provides data on the inter-relationship between tumour vasculature and immune cell recruitment.
人们已采用多种策略来释放基因疗法治疗癌症的潜力，涉及通过各种方法递送的多种治疗性基因。免疫疗法已成为癌症基因治疗采用的主要策略之一，旨在刺激免疫系统靶向肿瘤抗原。在本研究中，研究了AAV2介导的对生长中肿瘤进行免疫治疗的可行性，包括单独使用以及与抗血管生成疗法联合使用的情况。
分别对携带皮下JBS纤维肉瘤或Lewis肺癌（LLC）肿瘤异种移植的免疫活性Balb/C或C57小鼠，通过向皮下肿瘤瘤内注射编码免疫上调细胞因子粒细胞巨噬细胞集落刺激因子（GM-CSF）和共刺激分子B7-1的AAV2载体进行治疗，单独使用或在肿瘤诱导前14天与肌肉内（IM）注射编码Nk4的AAV2载体联合使用。监测所有动物的肿瘤生长和存活情况。对治愈的动物用致瘤剂量的原始肿瘤类型进行再次攻击。采用体内细胞毒性试验来研究治疗动物中细胞介导反应的建立情况。
AAV2介导的GM-CSF、B7-1治疗导致两种肿瘤模型中的肿瘤生长显著减少且存活率增加。治愈的动物对再次攻击具有抗性，并证明诱导了T细胞介导的抗肿瘤反应。将脾细胞过继转移至未致敏动物可防止肿瘤形成。肌肉内（IM）注射Nk4诱导的Nk4全身产生显著减少了皮下肿瘤生长。然而，Nk4治疗与GM-CSF、B7-1疗法联合使用降低了免疫疗法的疗效。
总体而言，本研究证明了体内AAV2介导的免疫基因治疗的潜力，并提供了关于肿瘤脉管系统与免疫细胞募集之间相互关系的数据。
