title: N-(4-hydroxyphenyl)retinamide increases ceramide and is cytotoxic to acute lymphoblastic leukemia cell lines, but not to non-malignant lymphocytes.
abstract: The retinoid, N-(4-hydroxyphenyl)retinamide (4-HPR), mediates p53-independent cytotoxicity and can increase reactive oxygen species and ceramide in solid tumor cell lines. We determined changes in ceramide and cytotoxicity upon treatment with 4-HPR (3-12 microM) in six human acute lymphoblastic leukemia (ALL) cell lines: T cell (MOLT-3, MOLT-4, CEM), pre-B-cell (NALM-6, SMS-SB), and null cell (NALL-1). Exposure to 4-HPR (12 microM) for 96 h caused 4.7 (MOLT-3), 3.5 (MOLT-4), 3.9 (CEM), 2.9 (NALM-6), 4.7 (SMS-SB), AND 4.5 (NALL-1) logs of cell kill. The average 4-HPR concentration that killed 99% of cells (LC(99)) for all six lines was 4.8 microM (range: 1.5-8.9 microM). Treatment with 4-HPR (9 microM) for 24 h resulted in an 8.9 +/- 1.0-fold (range: 4.9-15.7-fold) increase of ceramide. Ceramide increase was time- and dose-dependent and abrogated by inhibitors of de novo ceramide synthesis. Concurrent inhibition of ceramide glycosylation/acylation by d,l-threo-(1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol) (PPMP) further increased ceramide levels, and synergistically increased 4-HPR cytotoxicity in four of six ALL cell lines. 4-HPR was minimally cytotoxic to peripheral blood mononuclear cells and a lymphoblastoid cell line, and increased ceramide <2-fold. Thus, 4-HPR was cytotoxic and increased ceramide in ALL cell lines, but not in non-malignant lymphoid cell types.
authors: Division of Hematology-Oncology, Childrens Hospital Los Angeles, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA.
authors: P H
authors: PH
authors: O'Donnell
authors: W-X
authors: WX
authors: Guo
authors: C P
authors: CP
authors: Reynolds
authors: B J
authors: BJ
authors: Maurer
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002518:Ceramides / Q000096:biosynthesis* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D017313:Fenretinide / Q000494:pharmacology*; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology*; D013107:Sphingolipids / Q000494:pharmacology; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: C095823:1-phenyl-2-palmitoylamino-3-morpholino-1-propanol; D000970:Antineoplastic Agents; D002518:Ceramides; D009025:Morpholines; D013107:Sphingolipids; D017313:Fenretinide