Abstract 1471: A novel mouse model of upper tract urothelial carcinoma influenced by gut microbiota
Authors: Yamamoto Akinaru , Kawashima Atsunari , Jingushi Kentaro , Nesrine Sassi , Horibe Yuki , Yoshimura Akihiro , Tani Masaru , Yutong Liu , Oka toshiki , Okuda Yohei , Uemura toshihiro , Yamamichi Gaku , Ishizuya Yu , Yamamoto Yoshiyuki , Kato Taigo , Hatano Koji , Nonomura Norio 
Published: March 2024

Introduction & Objective: Recently, it has been revealed that bladder cancer (BC) and upper tract urothelial carcinoma (UTUC) are biologically distinct diseases. Mouse models of BC carcinogenesis have been established using N-butyl-N-(4-hydro-oxybutyl) nitorosamine (BBN) for a long time, but there are few reports of UTUC carcinogenesis with high incidence. Therefore, the UTUC carcinogenesis mouse model is expected. The aim of this study is to establish a novel mouse model of UTUC carcinogenesis and to identify the characteristics of this model.

Methods: We used two strains (C57BL/6 and BALB/c) of male and female mice and fed 0.05% BBN from 6 weeks old to the harvest day. Both sides of upper urinary tract from mice drinking BBN or tap water were subjected to whole exome sequencing and whole transcriptome sequencing (WTS) to assess its genetic similarity to human UTUC. Microbiome in gut were assessed by 16S ribosomal RNA gene sequencing (16S rRNA-seq). Metabolic differences in feces, serum and liver between UTUC mice and healthy mice were evaluated by comprehensive metabolomic analysis. Inflammatory mediators were assessed by quantitative polymerase chain reaction (qPCR).

Results: Only BALB/c female showed higher incidence of UTUC than BC, while the other strains rarely had UTUC. This model showed SBS5-like mutational pattern. The frequent mutated gene list showed similarity to human UTUC. In terms of gene expression, this model belonged basal subtype. We detected 593 differentially expressed genes between cancerous side and non-cancerous side of upper urinary tract in this model, which could also classify human UTUC and adjacent normal samples. The cancerous side of upper urinary tract enriched several inflammation related pathways such as Nfkb and Tnf pathway. We validated the upregulation of inflammatory gene expression in upper urinary tract (Il6, Il1b, Tnfa, Relb) by qPCR (all: p &lt; 0.05). 16S rRNA-seq revealed that Firmicutes was enriched in feces. Metabolomic analysis revealed that some amino acids in feces and FAD in serum were upregulated. Feeding with amino acid mediated diet changed gut environment. Firmicutes in feces and FAD in both feces and serum were downregulated consistently. This diet suppressed inflammatory gene expression in upper urinary tract (Il6, Il1b, Tnfa, Relb, Cd38, Tnfrsf1b and Kdm1a; all: p &lt; 0.05). Finally, UTUC was disappeared but not BC in this model treated by BBN with amino acid mediated diet.

Conclusion: We have established a novel mouse model developing UTUC with high incidence that genetically mimics human UTUC. In addition, amino acid mediated diet can change both microbiome and metabolome in gut of this model, downregulate host’s inflammatory reaction to BBN in upper urinary trat and suppress the UTUC carcinogenesis.

Citation Format: Akinaru Yamamoto, Atsunari Kawashima, Kentaro Jingushi, Sassi Nesrine, Yuki Horibe, Akihiro Yoshimura, Masaru Tani, Liu Yutong, toshiki Oka, Yohei Okuda, toshihiro Uemura, Gaku Yamamichi, Yu Ishizuya, Yoshiyuki Yamamoto, Taigo Kato, Koji Hatano, Norio Nonomura. A novel mouse model of upper tract urothelial carcinoma influenced by gut microbiota [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1471.