title: Comparative lipid analysis in the normal and cancerous organoids of MDCK cells.
abstract: Epithelial organs are made of a well-polarized monolayer of epithelial cells, and their morphology is maintained strictly for their proper functioning. The roles of lipids are not only to generate the membrane, but also to provide the specific domains for signal transduction, or to transmit signals as second messengers. By using a liquid chromatography-electrospray ionization mass spectrometry (LC-MS)/MS method, we here analyzed sphingolipids in MDCK cysts under various conditions. Our result showed that, compared to the three-dimensional cyst, the two-dimensional MDCK sheet is relatively enriched in sphingolipids. During cystogenesis, the contents of sphingomyelin (SM) and lactocylceramide (LacCer)-but, none those of ceramide, hexocylceramide, or GM3-are altered depending on their acyl chains. While the total SM is decreased more efficiently by SMS-1 knockdown than by SMS-2 knockdown, depletion of SMS-2, but not SMS-1, inhibits cyst growth. Finally upon the switching on of activated K-Ras expression which induces luminal cell filling, ceramide and LacCer are increased. Our parallel examinations of the microarray data for mRNA of sphingolipid metabolic enzymes failed to fully explain the remodelling of the sphingolipids of MDCK cysts. However, these results should be useful to investigate the cell-type- and structure-specific lipid metabolism.
authors.affiliation: Department of Oncologic Pathology; Department of Pediatric Surgery; and.
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Yoshizaki
authors.affiliation: Department of Hematology/Immunology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Ogiso
authors.affiliation: Department of Hematology/Immunology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Okazaki
authors.affiliation: Department of Oncologic Pathology; kiyokawa@kanazawa-med.ac.jp.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kiyokawa
mesh_terms: D000818:Animals; D004285:Dogs; D055785:Gene Knockdown Techniques; D061985:Madin Darby Canine Kidney Cells; D013058:Mass Spectrometry; D008563:Membrane Lipids / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009940:Organoids / Q000378:metabolism*
chemical_list: D008563:Membrane Lipids; D008565:Membrane Proteins
keywords: K-Ras; MDCK; mass spectrometry; organoid; sphingolipids