Jiang Yu, Li Xiyuan, Qian Fenghui, Sun Bingbing, Wang Xiyuan, Zhang Yan, Zhang Deqiang, Geng Meiyu, Xie Zuoquan, Yang Sheng
Shanghai Research and Development Center of Industrial Biotechnology, Shanghai, China.
Huzhou Research Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Huzhou, China.
Research (Wash D C). 2023;6:0102. doi: 10.34133/research.0102. Epub 2023 Mar 30.
The stimulator of interferon genes (STING) protein is an important and promising innate immune target for tumor therapy. However, the instability of the agonists of STING and their tendency to cause systemic immune activation is a hurdle. The STING activator, cyclic di-adenosine monophosphate (CDA), produced by the modified Nissle 1917, shows high antitumor activity and effectively reduces the systemic effects of the "off-target" caused by the activation of the STING pathway. In this study, we used synthetic biological approaches to optimize the translation levels of the diadenylate cyclase that catalyzes CDA synthesis in vitro. We developed 2 engineered strains, CIBT4523 and CIBT4712, for producing high levels of CDA while keeping their concentrations within a range that did not compromise the growth. Although CIBT4712 exhibited stronger induction of the STING pathway corresponding to in vitro CDA levels, it had lower antitumor activity than CIBT4523 in an allograft tumor model, which might be related to the stability of the surviving bacteria in the tumor tissue. CIBT4523 exhibited complete tumor regression, prolonged survival of mice, and rejection of rechallenged tumors, thus, offering new possibilities for more effective tumor therapy. We showed that the appropriate production of CDA in engineered bacterial strains is essential for balancing antitumor efficacy and self-toxicity.
干扰素基因刺激蛋白（STING）是肿瘤治疗中一个重要且有前景的固有免疫靶点。然而，STING激动剂的不稳定性及其引发全身免疫激活的倾向是一个障碍。由改良的1917年大肠杆菌Nissle菌株产生的STING激活剂环二磷酸腺苷（CDA）具有高抗肿瘤活性，并有效降低了STING途径激活所导致的“脱靶”全身效应。在本研究中，我们采用合成生物学方法优化了体外催化CDA合成的二腺苷酸环化酶的翻译水平。我们构建了2株工程菌CIBT4523和CIBT4712，用于高水平生产CDA，同时将其浓度控制在不影响生长的范围内。尽管CIBT4712在体外对应CDA水平时对STING途径的诱导更强，但在同种异体移植肿瘤模型中，其抗肿瘤活性低于CIBT4523，这可能与肿瘤组织中存活细菌的稳定性有关。CIBT4523表现出肿瘤完全消退、小鼠生存期延长以及对再次接种肿瘤的排斥反应，因此为更有效的肿瘤治疗提供了新的可能性。我们表明，工程菌株中适当的CDA产量对于平衡抗肿瘤疗效和自身毒性至关重要。
