Targeting lipid metabolism by the lipoprotein lipase inhibitor orlistat results in apoptosis of B-cell chronic lymphocytic leukemia cells.
Constitutively activated pathways contribute to apoptosis resistance in chronic lymphocytic leukemia (CLL). Little is known about the metabolism of lipids and function of lipases in CLL cells. Performing gene expression profiling including B-cell receptor (BCR) stimulation of CLL cells in comparison to healthy donor CD5+ B cells, we found significant overexpression of lipases and phospholipases in CLL cells. In addition, we observed that the recently defined prognostic factor lipoprotein lipase (LPL) is induced by stimulation of BCR in CLL cells but not in CD5+ normal B cells. CLL cellular lysates exhibited significantly higher lipase activity compared to healthy donor controls. Incubation of primary CLL cells (n=26) with the lipase inhibitor orlistat resulted in induction of apoptosis, with a half-maximal dose (IC(50)) of 2.35 microM. In healthy B cells a significantly higher mean IC(50) of 148.5 microM of orlistat was observed, while no apoptosis was induced in healthy peripheral blood mononuclear cells (PBMCs; P<0.001). Orlistat-mediated cytotoxicity was decreased by BCR stimulation. Finally, the cytotoxic effects of orlistat on primary CLL cells were enhanced by the simultaneous incubation with fludarabine (P=0.003). In summary, alterations of lipid metabolism are involved in CLL pathogenesis and might represent a novel therapeutic target in CLL.
Pallasch
C P
CP
Laboratory of Cellular Immunotherapy, Clinic I of Internal Medicine, University of Cologne, Cologne, Germany.
Schwamb
J
J
Königs
S
S
Schulz
A
A
Debey
S
S
Kofler
D
D
Schultze
J L
JL
Hallek
M
M
Ultsch
A
A
Wendtner
C-M
CM
D017209:Apoptosis / Q000187:drug effects*; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D020128:Inhibitory Concentration 50; D007783:Lactones / Q000494:pharmacology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects; D050356:Lipid Metabolism / Q000187:drug effects*; D008071:Lipoprotein Lipase / Q000037:antagonists & inhibitors*; D005810:Multigene Family / Q000187:drug effects; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D000077403:Orlistat; D010740:Phospholipases / Q000096:biosynthesis / Q000235:genetics; D051562:Proto-Oncogene Proteins c-bcr / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000201:enzymology; D014740:Vidarabine / Q000031:analogs & derivatives / Q000494:pharmacology
D005230:Fatty Acids, Nonesterified; D007783:Lactones; D009363:Neoplasm Proteins; D000077403:Orlistat; C496613:BCR protein, human; D051562:Proto-Oncogene Proteins c-bcr; D010740:Phospholipases; D008071:Lipoprotein Lipase; D014740:Vidarabine; C024352:fludarabine