The genome analyses identified driver genes for gastric and colorectal cancer. We have constructed novel mouse models and tumor-derived organoid transplantation models to examine the mechanisms of development and metastasis of gastrointestinal cancers.
In the concept of polyclonal metastasis, cell clusters are detached from the primary site and develops genetically heterogenous metastatic lesions. Using the mouse intestinal tumor-derived organoids, we found that malignant metastatic cells can generate fibrotic niche in the liver, which support survival and proliferation of non-metastatic cells within the same clusters and develop polyclonal metastasis (Kok SY, Oshima H, et al, Nat Commun, 2021).
Using the high speed (HS)-scanning ion conductance microscope (SICM), we have analyzed cell surface topography and physical properties including stiffness of intestinal tumor-derived organoids, and identified metastatic cell-specific mechanical characteristics (Wang D, et al, Biomaterials, 2022).
AKTP organoids carrying four driver mutations in Apc, Kras, Tgfbr2 and Trp53 were established from metastatic intestinal tumors. We found that about 30% of AKTP cells lost metastatic ability and eliminated from the tumor population by negative selection. Thus, it is possible that cancer evolution is promoted by both positive and negative selections (Morita A, et al, Cancer Sci, 202).
When metastatic AKTP and non-metastatic AP cells are co-disseminated to the liver, AKTP cells induce fibrotic niche generation, which support survival and proliferation of AP cells, leading to polyclonal metastasis.
(modified from Kok SY, Oshima H, Nat Commun, 2020)
In vivo imaging analysis indicated that approximately 30% of subclones of metastatic AKTP tumor cells lose metastatic ability. Such tumor cells are continuously eliminated by negative selection from the tumor tissues.
(modified from Morita A, Nakayama M, et al, Cancer Sci, 2020)