The genus Sphingobacterium, whose members are Gram-negative non-fermentative rods, possesses ceramides and related sphingophospholipids (SPLs) with isoheptadecasphinganine and 2-hydroxy or non-hydroxy isopentadecanoic acid. This paper reports evidence that ceramides isolated from Sphingobacterium spiritivorum ATCC 33861 induce endonucleolytic DNA cleavage in @entity1 @entity1778 HL-60 cells in vitro, which is the primary characteristic biochemical marker for apoptosis or programmed cell death. Ceramides and SPLs also induced DNA fragmentation and @entity522 activation, followed by changes in morphology, such as alterations in the size of nuclei and cells, and cell cycle shortening. Apoptotic activity correlated with the ceramide structure. Ceramide with a 2-hydroxy fatty acid showed stronger apoptotic activity than ceramide with a non-hydroxy fatty acid. Furthermore, the major five SPLs (ceramide phosphorylethanolamine-1 and -2, ceramide phosphorylinositol-1 and -2, and ceramide phosphorylmannose-1) showed apoptosis-inducing activity in HL-60 cells, indicating that the ceramide moiety of the SPLs plays a crucial role as the intracellular second messenger but that their hydrophilicity is less important in this regard. The hydrophilic part of SPLs may play a role in other cellular response systems. The involvement of @entity1197 was implicated in the apoptotic event since @entity1197 expression was observed after 3 or 4 h stimulation of HL-60 cells with bacterial ceramides. However, a time-course study for @entity522 activation indicated maximal activity at 1 h after stimulation with bacterial ceramides, suggesting that two (or possibly more) mechanisms of signal transduction, Fas-dependent and Fas-independent, may be involved. @entity1197 expression and @entity522 activation by five kinds of SPLs were observed after 3 or 4 h. These results indicate that there is a difference in the response of HL-60 cells to bacterial ceramides and SPLs.

Bacterial ceramides and sphingophospholipids induce apoptosis of XXXX leukaemic cells.

@entity1 :: ('9606', 'Species') :: ['human'] @entity1197 :: ('355', 'Gene') :: ['Fas antigen'] @entity1778 :: ('MESH:D007938', 'Disease') :: ['myeloid leukaemia'] @entity522 :: ('836', 'Gene') :: ['caspase-3']
@entity1 :: (9606,Species) :: ['human']
