| 研究実績の概要 |
Our mechanistic understanding of gastric cancer remains limited, hampering the development of more effective therapeutics. Using proprietary new mouse models and ex vivo culture assays, we will i) evaluate the contribution of Lgr5-expressing corpus stem cells to inflammation-driven cancer initiation ii) generate the first inflammation driven mouse models of metastatic gastric cancer to functionally evaluate Lgr5-expressing tumor cells as cancer stem cells iii) evaluate the contribution of TCGA derived driver mutations such as RhoA and RNF43 to in vivo gastric cancer formation. These research avenues will deliver invaluable mechanistic insight into gastric cancer progression and will reveal novel opportunities for therapeutic intervention.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
1. We activated Lgr5-driven lineage tracing in adult Gan/Lgr5-2A-CreERT2/RosatdTomato mice with established chronic gastric inflammation via IP injection of tamoxifen. The tdTomato expression in the corpus epithelium was subsequently analyzed via confocal imaging/IHC to determine the in vivo output of the Lgr5+ corpus cells within the inflamed stomach epithelium. In parallel, we isolated the Lgr5-EGFP+ corpus cells from inflamed stomachs via FacSorting and evaluated their ability by generating epithelial organoids ex vivo. Organoid forming capacity of Lgr5+ cells from healthy and inflamed stomach epithelia was directly compared using in vitro assay.
2. We tried to generate the first inflammation-driven mouse model of invasive, metastatic gastric cancer to facilitate the functional evaluation of Lgr5-expressing tumor cells as cancer stem cells. Although, we succeeded to established a new invasive, metastatic gastric cancer mouse model, we couldn’t incorporate the inflammation setting in that model by March 2018. Finally, we succeeded to establish the inflammation-driven mouse model by July 2018. Using this mouse model, the functional evaluation of the cancer stem cell identity of the tumor-resident Lgr5-expressing cells was achieved by administering diphtheria toxin to mice with established gastric cancer/metastases. This achieve the selective ablation of the tumor-resident Lgr5+ cells in vivo. Any resulting effect on tumor growth will be subsequently evaluated via histological/marker analysis of the corpus regions from treated mice over months.
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