Cho Yang Je, Ahn Bo Young, Lee Na Gyong, Lee Dong Hyeon, Kim Doo-Sik
Department of Biochemistry, College of Science, Yonsei University, Seoul 120-749, Korea.
Vaccine. 2006 Jul 26;24(31-32):5862-71. doi: 10.1016/j.vaccine.2006.04.048. Epub 2006 May 6.
The use of Escherichia coli DNA or lipopolysaccharide (LPS) as an immunotherapy is often associated with unacceptable toxicity and insufficient therapeutic effects. In this study, we investigated the efficacy of using a combination of bacterial DNA fragments and LPS as an anticancer agent. LPS was isolated from an E. coli strain expressing short-carbohydrate-chain-containing LPS and subjected to alkaline hydrolysis to remove lipid A. The ability to induce tumor necrosis factor-alpha (TNF-alpha) release in human whole blood cells was significantly lower for the LPS devoid of lipid A than for its parent form. The immunostimulating activity of E. coli DNA fragments of various sizes were tested. Those of 0.2-0.5 kb in size exhibited the highest activity in whole blood assays, whereas those of size 0.5-2.0 kb exhibited the highest adjuvant activity in mice. A combination of 0.5-2.0-kb DNA fragments and modified LPS at a ratio of 100:1, designated CIA07, exhibited higher immunostimulating activity than each substance alone, and its antitumor activity was significantly higher than that of Bacillus Calmette-Guerin in a mouse bladder cancer model. An intraperitoneal injection of CIA07 at a dose of 25mg/kg body weight caused no apparent adverse effects in mice and guinea pigs. Taken together, these data demonstrate that CIA07 exhibits potent immunostimulating activity with no apparent toxicity, and therefore warrant the further development of CIA07 as an immunotherapy for cancer treatment.
将大肠杆菌DNA或脂多糖（LPS）用作免疫疗法常常伴随着不可接受的毒性以及治疗效果不足的问题。在本研究中，我们调查了使用细菌DNA片段和LPS的组合作为抗癌剂的疗效。LPS是从表达含短碳水化合物链的LPS的大肠杆菌菌株中分离出来的，并进行碱水解以去除脂质A。不含脂质A的LPS在人全血细胞中诱导肿瘤坏死因子-α（TNF-α）释放的能力明显低于其亲本形式。测试了各种大小的大肠杆菌DNA片段的免疫刺激活性。大小为0.2 - 0.5 kb的片段在全血试验中表现出最高活性，而大小为0.5 - 2.0 kb的片段在小鼠中表现出最高的佐剂活性。以100:1的比例组合0.5 - 2.0 kb的DNA片段和修饰的LPS，命名为CIA07，其免疫刺激活性高于单独的每种物质，并且在小鼠膀胱癌模型中其抗肿瘤活性明显高于卡介苗。以25mg/kg体重的剂量腹腔注射CIA07在小鼠和豚鼠中未引起明显的不良反应。综上所述，这些数据表明CIA07具有强大的免疫刺激活性且无明显毒性，因此有必要进一步开发CIA07作为癌症治疗的免疫疗法。
