Abstract：
Oral bacteria naturally secrete extracellular vesicles (EVs), which have attracted attention for their promising biomedical applications including cancer therapeutics. However, our understanding of EV impact on tumor progression is hampered by limited in vivo models. In this study, we propose a facile in vivo platform for assessing the effect of EVs isolated from different bacterial strains on oral cancer growth and dissemination using the larval zebrafish model. EVs were isolated from: wild-type Aggregatibacter actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; and wild-type Porphyromonas gingivalis. Cancer cells pretreated with EVs were xenotransplanted into zebrafish larvae, wherein tumor growth and metastasis were screened. We further assessed the preferential sites for the metastatic foci development. Interestingly, EVs from the CDT-lacking A. actinomycetemcomitans resulted in an increased tumor growth, whereas EVs lacking the lipopolysaccharide O-antigen reduced the metastasis rate. P. gingivalis-derived EVs showed no significant effects. Cancer cells pretreated with EVs from the mutant A. actinomycetemcomitans strains tended to metastasize less often to the head and tail compared to the controls. In sum, the proposed approach provided cost- and labor-effective yet efficient model for studying bacterial EVs in oral carcinogenesis, which can be easily extended for other cancer types. Furthermore, our results support the notion that these nanosized particles may represent promising targets in cancer therapeutics.
摘要：
口腔细菌自然分泌细胞外囊泡（EV），这引起了人们的注意，他们有前途的生物医学应用，包括癌症治疗。然而,有限的体内模型阻碍了我们对EV对肿瘤进展影响的理解.在这项研究中,我们提出了一个简单的体内平台，用于使用幼虫斑马鱼模型评估从不同细菌菌株分离的EV对口腔癌生长和传播的影响。EV分离自：野生型Aggregatibacter放线菌及其突变菌株，缺乏细胞致死扩张毒素（CDT）或脂多糖（LPS）O抗原；和野生型牙龈卟啉单胞菌。用电动汽车预处理的癌细胞异种移植到斑马鱼幼虫中，其中筛选肿瘤生长和转移。我们进一步评估了转移灶发展的优先部位。有趣的是,来自CDT缺乏放线菌的EV导致肿瘤生长增加，而缺乏脂多糖O抗原的EV降低了转移率。牙龈卟啉单胞菌衍生的EV没有显着影响。与对照相比，用来自突变型放线菌群菌株的EV预处理的癌细胞倾向于较少转移到头部和尾部。总之,所提出的方法为研究口腔癌发生中的细菌EVs提供了成本和劳动力有效但有效的模型，可以很容易地扩展到其他癌症类型。此外，我们的研究结果支持这样的观点,即这些纳米颗粒可能代表癌症治疗中的有希望的靶点.
