title: Differential effects of 2- and 3-series E-prostaglandins on in vitro expansion of Lgr5+ colonic stem cells.
abstract: Arachidonic acid (20:4(Δ5,8,11,14), AA)-derived prostaglandin E2 (PGE2) promotes colon cancer development. In contrast, chemoprotective n-3 polyunsaturated fatty acids supplant AA, thereby decreasing PGE2 biosynthesis in colonocytes, with eicosapentaenoic acid (20:5(Δ5,8,11,14,17), EPA) in particular being metabolized to a novel 3-series E-prostaglandin (PGE3), a putative anti-tumorigenic-cyclooxygenase metabolite. Because transformation of adult stem cells is an extremely important route toward initiating intestinal cancer, we utilized the leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5)-enhanced green fluorescent protein-internal ribosome entry site (IRES)-creER(T2) knock-in mouse model to isolate and culture colonic organoids, in order to document ex vivo responses to exogenous PGE2 and PGE3. Colonic crypts were isolated from transgenic mice and cultured in a Matrigel-based three-dimensional platform. Organoids were treated with exogenous PGE2, PGE3 or dimethyl sulfoxide (vehicle control) for 5 days and the number of viable organoids was recorded daily. Subsequently, samples were processed for immunohistochemistry, flow cytometry and real-time PCR analyses. PGE2 promoted optimal organoid growth and induced significantly higher levels of cell proliferation (P < 0.05) compared with PGE3 and control. In contrast, the Lgr5-green fluorescent protein-positive stem cell number was uniquely elevated by >2-fold in PGE2-treated cultures compared with PGE3 and control. This coincided with the upregulation of stem-cell-related Sox9, Axin2 and Cd44 messenger RNAs. Our results demonstrate that relative to AA-derived PGE2, a known promoter of colon tumorigenesis, EPA-derived PGE3 has diminished ability to support colonic stem cell expansion in mouse colonic organoids.
authors: Program in Integrative Nutrition and Complex Diseases.
authors: Yang-Yi
authors: YY
authors: Fan
authors: Laurie A
authors: LA
authors: Davidson
authors: Evelyn S
authors: ES
authors: Callaway
authors: Jennifer S
authors: JS
authors: Goldsby
authors: Robert S
authors: RS
authors: Chapkin
mesh_terms: D002455:Cell Division / Q000187:drug effects*; D003106:Colon / Q000166:cytology / Q000187:drug effects*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D011453:Prostaglandins / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects*
chemical_list: D011453:Prostaglandins; D049452:Green Fluorescent Proteins