title: WIN55,212-2 induces cytoplasmic vacuolation in apoptosis-resistant MCL cells.
abstract: Cannabinoid receptors 1 (CB1) and/or 2 (CB2) are overexpressed in many types of human malignancies including mantle cell lymphoma (MCL). Agonists to CB1 and CB2 promote ceramide de novo synthesis, p38-mitogen-activated protein kinase-dependent activation of caspase-3 and apoptotic cell death in most MCLs. However, in this report we describe that in some MCLs the response to treatment with cannabinoids decreased cell viability as assessed by metabolic activity but did not involve the caspase-3 cascade or loss of plasma membrane integrity. Both primary cells from one MCL patient and the MCL cell line Granta519 responded to treatment with cannabinoids by formation of cycloheximide-sensitive cytoplasmic vacuoles, but did not enter apoptosis. The persistent expression of mammalian homolog of Atg8 with microtubule-associated protein-1 light chain-3 II (LC3 II) and p62, as well as the lack of protection from chloroquine, indicates that lysosomal degradation is not involved in this cytoplasmic vacuolation process, distinguishing from classical autophagy. Transmission electron microscopy images and immunofluorescence staining of endoplasmic reticulum (ER) chaperone calreticulin showed that the vacuoles were of ER origin and that chromatin remained normal. These features resemble paraptosis-like cell death-a third type of a programmed cell death not previously described in response to cannabinoids.
authors: Division of Pathology, Department of Laboratory Medicine, F46, Karolinska Institutet, Karolinska University Hospital, Huddinge, SE 141 86 Stockholm, Sweden. agata.wasik@ki.se
authors: A M
authors: AM
authors: Wasik
authors: S
authors: S
authors: Almestrand
authors: X
authors: X
authors: Wang
authors: K
authors: K
authors: Hultenby
authors: Å-L
authors: ÅL
authors: Dackland
authors: P
authors: P
authors: Andersson
authors: E
authors: E
authors: Kimby
authors: B
authors: B
authors: Christensson
authors: B
authors: B
authors: Sander
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D048588:Benzoxazines / Q000494:pharmacology*; D002186:Cannabinoids / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020522:Lymphoma, Mantle-Cell / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D046529:Microscopy, Electron, Transmission; D009025:Morpholines / Q000494:pharmacology*; D009281:Naphthalenes / Q000494:pharmacology*; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D043885:Receptor, Cannabinoid, CB2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
chemical_list: D048588:Benzoxazines; D002186:Cannabinoids; D009025:Morpholines; D009281:Naphthalenes; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone