Role of the Oral Microbiome in Oral Squamous Cell Carcinoma Progression

项目摘要 头颈癌是世界上第六大最常见的恶性肿瘤，口腔鳞状细胞癌是世界上第三大最常见的恶性肿瘤。 口腔癌（OSCC）是口腔中最常见的恶性肿瘤。尽管预后有所改善 对于许多其他人类癌症，OSCC的存活率几十年来几乎保持不变， 强调迫切需要新的治疗方式。越来越多的证据表明， 微生物组在促进各种癌症，包括胃癌，结肠癌和胆囊癌， 各种机制。与下胃肠道相反，口腔粘膜的作用和机制， 微生物组可能导致OSCC仍然不清楚。这个项目的推动力是， 模型，加上功能转录组学，提供了强大的新方法来阐明机制 这是OSCC中口腔微生物组致瘤作用的基础。在初步研究中，我们发现， 无菌小鼠定植微生物组，并与致癌物4-NQO的挑战，发展了许多 比保持无菌状态的小鼠有更多更大的肿瘤。转录过度活跃的候选病原体 表达了许多毒力特征，与以前在人类OSCC中的发现相似。 肿瘤浸润性白细胞（TIL）似乎被调节为免疫抑制性与保护性 表型在微生物组定殖的小鼠中。这些发现引出了我们的核心假设，即关键致病因素 口腔微生物组中的微生物促进OSCC进展，至少部分是通过诱导免疫抑制， 保护性免疫这将通过确定转录过度活跃的物种来测试， 强烈促进同基因小鼠口腔癌（MOC）细胞系移植物的生长和转移， 小鼠体内舌头。细菌代谢途径将通过元转录组学来表征， 微生物群调节的免疫以及通过RNASeq的肿瘤细胞应答。诱导的免疫应答 致瘤病原体将在局部和引流淋巴结中表征。Treg的功能和 骨髓来源的抑制细胞将通过在体内用免疫抑制抗体消除来评价。 将确定致瘤病原体对肿瘤细胞生长和侵袭的直接影响。目标是 确定关键的口腔致瘤细菌及其分子机制， OSCC进展。该项目的成功完成将提出新的以微生物组为重点的干预措施， 减少OSCC的发生和复发，并有助于开发下一代治疗方法， 这是一种致命的疾病。

Project Abstract Head and neck cancer represents the sixth most common malignancy worldwide, and oral squamous cell carcinomas (OSCC) are the most frequent malignancies in the oral cavity. Despite improvements in prognosis for many other human cancers, survival rates for OSCC have remained nearly unchanged for decades, emphasizing the urgent need for new treatment modalities. Mounting evidence indicates that the human microbiome plays a key role in promoting a variety of cancers, including stomach, colon and gall bladder, via various mechanisms. In contrast to the lower GI tract, the role of, and mechanisms by which, the oral microbiome may contribute to OSCC remain obscure. The impetus for this project is that gnotobiotic mouse models, coupled with functional transcriptomics, offer powerful new approaches to elucidate the mechanisms that underlie the tumorigenic effects of the oral microbiome in OSCC. In preliminary studies we found that germfree mice colonized with microbiomes, and challenged with the carcinogen 4-NQO, developed many more, and larger tumors than mice that remained germfree. Transcriptionally-hyperactive candidate pathogens were identified, which expressed numerous virulence signatures, paralleling previous findings in human OSCC. Tumor-infiltrating leukocytes (TIL) appeared to be modulated to an immunosuppressive vs protective phenotype in microbiome-colonized mice. These findings lead to our central hypothesis, that key pathogenic species in the oral microbiome promote OSCC progression, at least in part by inducing immunosuppression vs protective immunity. This will be tested by determining the transcriptionally-hyperactive species that most strongly promote the growth and metastasis of syngeneic mouse oral cancer (MOC) cell line orthografts in mouse tongues in vivo. Bacterial metabolic pathways will be characterized by metatranscriptomics, and the microbiome-modulated immune as well as tumor cell responses by RNASeq. Immune responses induced by tumorigenic pathogens will be characterized locally and in draining lymph nodes. The function of Treg and myeloid-derived suppressor cells will be evaluated by abrogation with immunotherapeutic antibodies in vivo. Direct effects of tumorigenic pathogens on tumor cell growth and invasion will be determined. The goal is to identify key oral tumorigenic bacteria and their molecular mechanisms that are responsible for promoting OSCC progression. Successful completion of this project will suggest new microbiome-focused interventions to reduce OSCC initiation and recurrence, and contribute to the development of next generation therapeutics for this recalcitrant and devastating disease.