2017 Fiscal Year Annual Research Report
Developing mouse models of inflammation-driven invasive gastric cancer to reveal novel therapeutic targets
| Project/Area Number |
17H01399
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| Research Institution | Kanazawa University |
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Principal Investigator |
NICHOLAS BARKER 金沢大学, その他部局等, リサーチ・プロフェッサー (30787651)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | gastric cancer / mouse model / inflammation / Lgr5 / organoid |
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| Outline of Annual Research Achievements |
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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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
1. We have been trying to establish the Gan/Lgr5-DTR-EGFP mouse model. In the Gan/Lgr5-2A-CreERT2/RosatdTomato mouse model, Tamoxifen administration activates tdTomato reporter gene expression in the Lgr5+ corpus cells, facilitating an evaluation of Lgr5+ stem cell activity in an inflammatory setting via in vivo lineage tracing.
2. Using our new Cldn18-ires-CreERT2 mouse strain, we have generated invasive mouse models of gastric cancer. Now we are trying to incorporate chronic inflammation in those models.
3. To evaluate the role of active RhoA and loss-of-function RNF43 mutations in gastric cancer progression, we have been generating the corresponding conditional mouse mutants. We will then incorporate these mutations into our Cldn18-CreERT2 driven conditional cancer models.
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| Strategy for Future Research Activity |
1. To evaluate inflammation-induced changes to Lgr5+ corpus stem cells, we will isolate the stomachs from the Gan/Lgr5-DTR-EGFP mice and perform immunohistochemical co-staining of EGFP and markers of proliferation, apoptosis and adult gastric cell lineages. Also, we will try a direct evaluation of Lgr5+ gastric stem cell behaviour in a chronic Wnt-driven inflammation setting via in vivo lineage tracing or ex vivo culture assay.
2. We will generate the first inflammation-driven mouse models of invasive, metastatic gastric cancer to facilitate a functional evaluation of Lgr5-expressing tumor cells as cancer stem cells. In vivo cancer formation will be initiated by administering Tamoxifen to adult mice with established gastric inflammation (aged 12-14 weeks). A functional evaluation of the cancer stem cell identity of the tumor-resident Lgr5-expressing cells will be achieved by administering diphtheria toxin to mice with established gastric cancer/metastases on consecutive days.
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