Institute of Ultrasonic Engineering in Medicine, Chongqing Medical University, Chongqing 400016, China.
World J Gastroenterol. 2010 Jul 28;16(28):3584-91. doi: 10.3748/wjg.v16.i28.3584.
To investigate whether tumor debris created by high-intensity focused ultrasound (HIFU) could trigger antitumor immunity in a mouse hepatocellular carcinoma model.
Twenty C57BL/6J mice bearing H22 hepatocellular carcinoma were used to generate antitumor vaccines. Ten mice underwent HIFU ablation, and the remaining 10 mice received a sham-HIFU procedure with no ultrasound irradiation. Sixty normal mice were randomly divided into HIFU vaccine, tumor vaccine and control groups. These mice were immunized with HIFU-generated vaccine, tumor-generated vaccine, and saline, respectively. In addition, 20 mice bearing H22 tumors were successfully treated with HIFU ablation. The protective immunity of the vaccinated mice was investigated before and after a subsequent H22 tumor challenge. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the cytotoxicity of splenic lymphocytes co-cultured with H22 cells was determined in vitro before the tumor challenge, and tumor volume and survival were measured in vivo after the challenge in each group. The mechanism was also explored by loading the vaccines with bone marrow-derived dendritic cells (DCs).
Compared to the control, HIFU therapy, tumor-generated and HIFU-generated vaccines significantly increased cytolytic activity against H22 cells in the splenocytes of the vaccinated mice (P < 0.001). The tumor volume was significantly smaller in the HIFU vaccine group than in the tumor vaccine group (P < 0.05) and control group (P < 0.01). However, there was no tumor growth after H22 rechallenge in the HIFU therapy group. Forty-eight-day survival rate was 100% in mice in the HIFU therapy group, 30% in both the HIFU vaccine and tumor vaccine groups, and 20% in the control group, indicating that the HIFU-treated mice displayed significantly longer survival than the vaccinated mice in the remaining three groups (P < 0.001). After bone marrow-derived DCs were incubated with HIFU-generated and tumor-generated vaccines, the number of mature DCs expressing MHC-II(+), CD80(+) and CD86(+) molecules was significantly increased, and interleukin-12 and interferon-gamma levels were significantly higher in the supernatants when compared with immature DCs incubated with mouse serum (P < 0.001). However, no differences of the number of mature DCs and cytokine levels were observed between the HIFU-generated and tumor-generated vaccines (P > 0.05).
Tumor debris remaining after HIFU can improve tumor immunogenicity. This debris releases tumor antigens as an effective vaccine to develop host antitumor immune response after HIFU ablation.
探讨高强度聚焦超声（HIFU）治疗后产生的肿瘤碎片能否在小鼠肝癌模型中引发抗肿瘤免疫。
将 20 只荷 H22 肝癌的 C57BL/6J 小鼠用于生成抗肿瘤疫苗。其中 10 只接受 HIFU 消融治疗，其余 10 只接受假 HIFU 处理（无超声辐照）。60 只正常小鼠随机分为 HIFU 疫苗组、肿瘤疫苗组和对照组。这些小鼠分别接受 HIFU 生成疫苗、肿瘤生成疫苗和生理盐水免疫。此外，20 只荷 H22 肿瘤的小鼠成功接受 HIFU 消融治疗。在随后的 H22 肿瘤挑战之前和之后，通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）测定法检测接种疫苗小鼠脾淋巴细胞与 H22 细胞共培养的细胞毒性，然后在每组小鼠中通过体内测量肿瘤体积和生存情况来评估保护免疫效果。通过负载骨髓来源的树突状细胞（DC）来探索其机制。
与对照组相比，HIFU 治疗、肿瘤生成和 HIFU 生成疫苗均显著提高了接种疫苗小鼠脾淋巴细胞对 H22 细胞的细胞毒活性（P<0.001）。HIFU 疫苗组的肿瘤体积明显小于肿瘤疫苗组（P<0.05）和对照组（P<0.01）。然而，在 HIFU 治疗组中，H22 再次挑战后没有肿瘤生长。HIFU 治疗组的 48 天生存率为 100%，HIFU 疫苗组和肿瘤疫苗组的生存率分别为 30%和 20%，对照组的生存率为 20%，这表明与接种疫苗的小鼠相比，HIFU 治疗的小鼠具有显著更长的生存时间（P<0.001）。与不成熟的 DC 孵育的鼠血清相比，用 HIFU 生成疫苗和肿瘤生成疫苗孵育的骨髓来源的 DC 表达 MHC-II(+)、CD80(+)和 CD86(+)分子的成熟 DC 数量明显增加，上清液中的白细胞介素-12 和干扰素-γ水平也明显升高（P<0.001）。然而，HIFU 生成疫苗和肿瘤生成疫苗之间成熟 DC 数量和细胞因子水平无差异（P>0.05）。
HIFU 治疗后残留的肿瘤碎片可以提高肿瘤的免疫原性。这种碎片释放肿瘤抗原，作为一种有效的疫苗，在 HIFU 消融后可诱导宿主产生抗肿瘤免疫反应。
