Development of cell and gene therapy for prostate cancer with dendritic cells engineered to produce interleukin-12

通过重组腺病毒载体体外感染，对骨髓源性DC进行基因工程改造，使其表达高水平的白介素-12 (IL-12)，无论是否含有共刺激分子B7-1。我们使用原位转移性前列腺癌小鼠临床前模型来比较原位和皮下DC递送的两种治疗方案。DC/IL-12或DC/IL-12/B7在体外产生高水平的生物活性IL-12。与DC/ β - gal对照相比，原位递送DC/IL-12或DC/IL-12/B7可显著抑制原发肿瘤生长，并减少自发性肺转移结节的数量。在存活实验中，原位注射DC/IL-12显示出显著的优势。与HBSS对照组相比，皮下肿瘤溶解液脉冲DC/IL-12显著降低肿瘤大小，提高生存率，但自发性肺转移数量的减少没有统计学意义。原位和皮下处理均能增强自然杀伤细胞（NK）和细胞毒性T淋巴细胞（CTL）的细胞溶解活性。在这个临床前模型中，基于基因修饰dc的肿瘤内免疫治疗被证明是一种有效的局部晚期前列腺癌的治疗策略，基于肿瘤生长抑制、转移抑制和生存改善。

Bone marrow-derived DC were genetically engineered to express high levels of interleukin-12 (IL-12) with or without the costimulatory molecule B7-1, by ex vivo infection with recombinant adenoviral vectors. We used an orthotopic metastatic mouse prostate cancer preclinical model to compare two therapeutic protocols for DC delivery, in situ and subcutaneous. In vitro DC/IL-12 or DC/IL-12/B7 produced high levels of biologically active IL-12. In situ delivery of DC/IL-12 or DC/IL-12/B7 induced a significant suppression of primary tumor growth compared to DC/beta gal controls, as well as reduced numbers of spontaneous lung metastatic nodules. In survival experiments, in situ DC/IL-12 injection demonstrated a significant advantage. Subcutaneous, tumor lysate pulsed DC/IL-12 significantly decreased tumor size and increased survival compared to HBSS controls but the decrease in the number of spontaneous lung metastases did not achieve statistical significance. Both in situ and subcutaneous treatments enhanced cytolytic activities of natural killer (NK) cells and cytotoxic T lymphocytes (CTL). In this preclinical model, gene-modified DC-based intratumoral immunotherapy was shown to be an effective therapeutic strategy for locally advanced prostate cancer based on tumor growth suppression, inhibition of metastasis and survival improvement.