Anti-CD20 therapeutic antibody rituximab modifies the functional organization of rafts/microdomains of B lymphoma cells

Semac, Isabelle; Palomba, Carmen; Kulangara, Karina; Klages, Natacha; van Echten-Deckert, Gerhild; Borisch, Bettina; Hoessli, Daniel

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Title		Anti-CD20 therapeutic antibody rituximab modifies the functional organization of rafts/microdomains of B lymphoma cells
Authors		Semac, Isabelle Palomba, Carmen Kulangara, Karina Klages, Natacha van Echten-Deckert, Gerhild Borisch, Bettina Hoessli, Daniel
Published in		Cancer research. 2003, vol. 63, no. 2, p. 534-540
Abstract		Incubation of Burkitt lymphoma-derived Raji cells at physiological temperature with submicromolar concentrations of humanized anti-CD20 antibody rituximab (RTX) redistributes CD20 to liquid-ordered, plasma membrane rafts. This accumulation of the CD20 tetraspan protein in rafts does not change the existing lipid and phosphoprotein composition but makes sphingolipids and the Src regulator Cbp/PAG (Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomain) transmembrane phosphoprotein more resistant to n-octyl-beta-pyranoside, a detergent that dissociates sphingolipid clusters. On the contrary, sphingolipids and Cbp/PAG are not protected by the presence of CD20 against the disruptive effects of methyl-beta-cyclodextrin, a cyclic carbohydrate that removes membrane cholesterol. After accumulation of CD20, the activity of the raft-associated Lyn kinase is down-regulated without apparent alteration of its relationship to substrates. Moreover, in rafts of lymphoblastoid cells that express lower amounts of Cbp/PAG, RTX redistributes CD20 to rafts but does not modulate the raft-associated protein tyrosine kinase activity, suggesting that the presence of Cbp/PAG protein in rafts is necessary for RTX to exert its transmembrane "signaling effects." Lastly, redistribution of CD20 in rafts renders the glycosylphosphatidyl inositol (GPI)-linked CD55 C'-defense protein hypersensitive to glycosylphosphatidyl inositol-specific phospholipases. By redistributing CD20 to rafts, RTX modifies their stability and organization and modulates the associated signaling pathways and C' defense capacity.
Keywords		Antibodies, Monoclonal/ pharmacology — Antigens, CD20/ metabolism — Antigens, CD55/metabolism — Antineoplastic Agents/ pharmacology — Cyclodextrins/chemistry — Glucosides/chemistry — Humans — Lymphoma, B-Cell/drug therapy/ metabolism — Membrane Lipids/metabolism — Membrane Microdomains/drug effects/ metabolism — Membrane Proteins/metabolism — Phospholipase D/metabolism — Phosphoproteins/metabolism — Type C Phospholipases/metabolism — beta-Cyclodextrins — src-Family Kinases/metabolism
Identifiers		PMID: 12543813
Full text		Article - Limited access to UNIGE Other version: http://cancerres.aacrjournals.org/content/63/2/534.full.pdf
Citation (ISO format)		SEMAC, Isabelle et al. Anti-CD20 therapeutic antibody rituximab modifies the functional organization of rafts/microdomains of B lymphoma cells. In: Cancer research, 2003, vol. 63, n° 2, p. 534-540. https://archive-ouverte.unige.ch/unige:11579