title: The natural product honokiol induces caspase-dependent apoptosis in B-cell chronic lymphocytic leukemia (B-CLL) cells.
abstract: B-cell chronic lymphocytic leukemia (B-CLL) remains an incurable disease that requires innovative new approaches to improve therapeutic outcome. Honokiol is a natural product known to possess potent antineoplastic and antiangiogenic properties. We examined whether honokiol can overcome apoptotic resistance in primary tumor cells derived from B-CLL patients. Honokiol induced caspase-dependent cell death in all of the B-CLL cells examined and was more toxic toward B-CLL cells than to normal mononuclear cells, suggesting greater susceptibility of the malignant cells. Honokiol-induced apoptosis was characterized by the activation of caspase-3, -8, and -9 and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP). Exposure of B-CLL cells to honokiol resulted in up-regulation of Bcl2-associated protein (Bax) and down-regulation of the expression of the key survival protein myeloid-cell leukemia sequence 1 (Mcl-1), which is associated with response to treatment in B-CLL patients. In addition, B-CLL cells pretreated with interleukin-4 (IL-4), a cytokine known to support B-CLL survival, underwent apoptosis when subsequently incubated with honokiol, indicating that honokiol could also overcome the prosurvival effects of IL-4. Furthermore, honokiol enhanced cytotoxicity induced by fludarabine, cladribine, or chlorambucil. These data indicate that honokiol is a potent inducer of apoptosis in B-CLL cells and should be examined for further clinical application either as a single agent or in combination with other anticancer agents.
authors.affiliation: Department of Medical Oncology, Mayer 522B, Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115, USA.
authors.forename: Traci E
authors.initials: TE
authors.lastname: Battle
authors.forename: Jack
authors.initials: J
authors.lastname: Arbiser
authors.forename: David A
authors.initials: DA
authors.lastname: Frank
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001713:Biphenyl Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D002699:Chlorambucil / Q000008:administration & dosage; D017338:Cladribine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D015847:Interleukin-4 / Q000494:pharmacology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D017705:Lignans / Q000008:administration & dosage / Q000494:pharmacology*; D031566:Magnolia; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D008517:Phytotherapy; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014740:Vidarabine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000498:Allyl Compounds; D010636:Phenols
chemical_list: D000970:Antineoplastic Agents; D001713:Biphenyl Compounds; D020169:Caspases; D002699:Chlorambucil; D017338:Cladribine; D004365:Drugs, Chinese Herbal; D015847:Interleukin-4; D017705:Lignans; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D014740:Vidarabine; C579095:MCL1 protein, human; C005499:honokiol; D000498:Allyl Compounds; D010636:Phenols; C024352:fludarabine