ABSTRACT
Dysplasia is considered a key transition state between pre-cancer and cancer in gastric carcinogenesis. However, the cellular or phenotypic heterogeneity and mechanisms of dysplasia progression have not been elucidated. We have established metaplastic and dysplastic organoid lines, derived from Mist1-Kras(G12D) mouse stomach corpus and studied distinct cellular behaviors and characteristics of metaplastic and dysplastic organoids. We also examined functional roles for Kras activation in dysplasia progression using Selumetinib, a MEK inhibitor, which is a downstream mediator of Kras signaling. Here, we report that dysplastic organoids die or show altered cellular behaviors and diminished aggressive behavior in response to MEK inhibition. However, the organoids surviving after MEK inhibition maintain cellular heterogeneity. Two dysplastic stem cell (DSC) populations are also identified in dysplastic cells, which exhibited different clonogenic potentials. Therefore, Kras activation controls cellular dynamics and progression to dysplasia, and DSCs might contribute to cellular heterogeneity in dysplastic cell lineages.
Subject(s)
Cell Lineage/genetics , Cell Transformation, Neoplastic/genetics , Gastric Mucosa/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Stomach Neoplasms/genetics , Animals , Benzimidazoles/pharmacology , Cell Lineage/drug effects , Cell Proliferation/genetics , Cell Transformation, Neoplastic/metabolism , Gastric Mucosa/pathology , Gene Expression Regulation, Neoplastic , Genetic Heterogeneity/drug effects , Humans , Kinetics , Mice, Inbred C57BL , Mice, Transgenic , Proto-Oncogene Proteins p21(ras)/metabolism , Signal Transduction/drug effects , Signal Transduction/genetics , Stomach/pathology , Stomach Neoplasms/metabolismABSTRACT
Microbiome-encoded ß-glucuronidase (GUS) enzymes play important roles in human health by metabolizing drugs in the gastrointestinal (GI) tract. The numbers, types, and diversity of these proteins in the human GI microbiome, however, remain undefined. We present an atlas of GUS enzymes comprehensive for the Human Microbiome Project GI database. We identify 3,013 total and 279 unique microbiome-encoded GUS proteins clustered into six unique structural categories. We assign their taxonomy, assess cellular localization, reveal the inter-individual variability within the 139 individuals sampled, and discover 112 novel microbial GUS enzymes. A representative in vitro panel of the most common GUS proteins by read abundances highlights structural and functional variabilities within the family, including their differential processing of smaller glucuronides and larger carbohydrates. These data provide a sequencing-to-molecular roadmap for examining microbiome-encoded enzymes essential to human health.
