title: Bcl-2 inhibitors induce apoptosis in chronic lymphocytic leukemia cells.
abstract: OBJECTIVE
  Antiapoptotic Bcl-2 is overexpressed in most cases of chronic lymphocytic leukemia (CLL). The inhibition of the antiapoptotic Bcl-2 proteins is an attractive strategy for either restoring normal apoptotic process in cancer cells or making these cells more susceptible to conventional chemotherapy. We studied the effect of Bcl-2 inhibitors on the viability of cells from CLL and other mature B-cell neoplasms.
  
  
  METHODS
  We studied the cytotoxic effects of four nonpeptidic cell-permeable Bcl-2 inhibitors (HA14-1, antimycin A, GX15-003, and GX15-070) on B cells from patients with CLL, mantle cell lymphoma (MCL), and splenic marginal zone lymphoma (SMZL). Moreover, we analyzed the effect of these inhibitors in combination with fludarabine or chlorambucil.
  
  
  RESULTS
  HA14-1 induced apoptosis with an EC50 lower than 50 microM in 26 of the 36 CLL samples analyzed. The mean EC50 for these sensitive patients was 23 +/- 2 microM. Antimycin A induced apoptosis in 13 of the 18 CLL samples analyzed. Both HA14-1 and antimycin A induced cytochrome c release from mitochondria and caspase-3 activation. Moreover, HA14-1 induced apoptosis in peripheral cells from MCL and SMZL. HA14-1 also induced apoptosis in CLL samples with alterations in p53 or ATM. Finally, GX compounds induced apoptosis in B cells from 9 of the 11 CLL samples tested. The combination of either HA14-1, antimycin A, or GX compounds with fludarabine or chlorambucil had additive cytotoxic effects on CLL cells.
  
  
  CONCLUSIONS
  Bcl-2 inhibitors induce apoptosis in CLL cells ex vivo and could be used in CLL as monotherapy or given in combination with current chemotherapy.
authors.affiliation: Departament de Ciències Fisiològiques II, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Campàs
authors.forename: Ana M
authors.initials: AM
authors.lastname: Cosialls
authors.forename: Montserrat
authors.initials: M
authors.lastname: Barragán
authors.forename: Daniel
authors.initials: D
authors.lastname: Iglesias-Serret
authors.forename: Antonio F
authors.initials: AF
authors.lastname: Santidrián
authors.forename: Llorenç
authors.initials: L
authors.lastname: Coll-Mulet
authors.forename: Mercè
authors.initials: M
authors.lastname: de Frias
authors.forename: Alicia
authors.initials: A
authors.lastname: Domingo
authors.forename: Gabriel
authors.initials: G
authors.lastname: Pons
authors.forename: Joan
authors.initials: J
authors.lastname: Gil
mesh_terms: D000968:Antimycin A / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001578:Benzopyrans / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D006801:Humans; D007211:Indoles; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000378:metabolism*; D020522:Lymphoma, Mantle-Cell / Q000188:drug therapy / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors; D011758:Pyrroles / Q000494:pharmacology*; D013160:Splenic Neoplasms / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D001578:Benzopyrans; D007211:Indoles; D009570:Nitriles; D019253:Proto-Oncogene Proteins c-bcl-2; D011758:Pyrroles; C456800:ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate; D000968:Antimycin A; C520962:obatoclax