title: Overcoming MDR-associated chemoresistance in HL-60 acute myeloid leukemia cells by targeting sphingosine kinase-1.
abstract: We examined the involvement of sphingosine kinase-1, a critical regulator of the sphingolipid balance, in susceptibility to antineoplastic agents of either sensitive or multidrug-resistant acute myeloid leukemia cells. Contrary to parental HL-60 cells, doxorubicin and etoposide failed to trigger apoptosis in chemoresistant HL-60/Doxo and HL-60NP16 cells overexpressing MRP1 and MDR1, respectively. Chemosensitive HL-60 cells displayed sphingosine kinase-1 inhibition coupled with ceramide generation. In contrast, chemoresistant HL-60/ Doxo and HL-60/VP16 had sustained sphingosine kinase-1 activity and did not produce ceramide during treatment. Enforced expression of sphingosine kinase-1 in chemosensitive HL-60 cells resulted in marked inhibition of apoptosis that was mediated by blockade of mitochondrial cytochrome c efflux hence suggesting a control of apoptosis at the pre-mitochondrial level. Incubation with cell-permeable ceramide of chemoresistant cells led to a sphingosine kinase-1 inhibition and apoptosis both prevented by sphingosine kinase-1 over-expression. Furthermore, F-12509a, a new sphingosine kinase inhibitor, led to ceramide accumulation, decrease in sphingosine 1-phosphate content and caused apoptosis equally in chemosensitive and chemoresistant cell lines that is inhibited by adding sphingosine 1-phosphate or overexpressing sphingosine kinase-1. F-12509a induced classical apoptosis hallmarks namely nuclear fragmentation, caspase-3 cleavage as well as downregulation of antiapoptotic XIAP, and release of cytochrome c and SMAC/Diablo.
authors.affiliation: Inserm, U466, Toulouse F-31432, France.
authors.forename: E
authors.initials: E
authors.lastname: Bonhoure
authors.forename: D
authors.initials: D
authors.lastname: Pchejetski
authors.forename: N
authors.initials: N
authors.lastname: Aouali
authors.forename: H
authors.initials: H
authors.lastname: Morjani
authors.forename: T
authors.initials: T
authors.lastname: Levade
authors.forename: T
authors.initials: T
authors.lastname: Kohama
authors.forename: O
authors.initials: O
authors.lastname: Cuvillier
mesh_terms: D000208:Acute Disease; D017209:Apoptosis / Q000187:drug effects; D016227:Benzoquinones / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002518:Ceramides / Q000096:biosynthesis; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D007951:Leukemia, Myeloid / Q000188:drug therapy / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology; D034622:RNA Interference / Q000502:physiology; D049349:Receptors, Lysosphingolipid / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D016227:Benzoquinones; D002518:Ceramides; D004317:Doxorubicin; D005047:Etoposide; D017853:Phosphotransferases (Alcohol Group Acceptor); D049349:Receptors, Lysosphingolipid; D000099157:Sphingosine Kinase; C411675:F 12509A