title: BH3 response profiles from neuroblastoma mitochondria predict activity of small molecule Bcl-2 family antagonists.
abstract: Bcl-2 family proteins regulate mitochondrial apoptosis downstream of diverse stressors. Cancer cells frequently deregulate Bcl-2 proteins leading to chemoresistance. We have optimized a platform for solid tumors in which Bcl-2 family resistance patterns are inferred. Functional mitochondria were isolated from neuroblastoma (NB) cell lines, exposed to distinct BH3-domain peptides, and assayed for cytochrome c release. Such BH3 profiles revealed three patterns of cytochrome c response. A subset had a dominant NoxaBH3 response implying Mcl1 dependence. These cells were more sensitive to small molecules that antagonize Mcl1 (AT-101) than those that antagonize Bcl-2, Bcl-xL and Bcl-w (ABT-737). A second subset had a dominant BikBH3 response, implying a Bcl-xL/-w dependence, and was exquisitely sensitive to ABT-737 (IC(50) <200 nM). Finally, most NB cell lines derived at relapse were relatively resistant to pro-death BH3 peptides and Bcl-2 antagonists. Our findings define heterogeneity for apoptosis resistance in NB, help triage emerging Bcl-2 antagonists for clinical use, and provide a platform for studies to characterize post-therapy resistance mechanisms for NB and other solid tumors.
authors.affiliation: The Children's Hospital of Philadelphia, Philadelphia, 19104-4318, USA.
authors.forename: K C
authors.initials: KC
authors.lastname: Goldsmith
authors.forename: B J
authors.initials: BJ
authors.lastname: Lestini
authors.forename: M
authors.initials: M
authors.lastname: Gross
authors.forename: L
authors.initials: L
authors.lastname: Ip
authors.forename: A
authors.initials: A
authors.lastname: Bhumbla
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: H
authors.initials: H
authors.lastname: Zhao
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: M D
authors.initials: MD
authors.lastname: Hogarty
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001713:Biphenyl Compounds / Q000494:pharmacology; D002460:Cell Line; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D006072:Gossypol / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D008928:Mitochondria / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D009596:Nitrophenols / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors*; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: C501332:ABT-737; C474007:Bax protein (53-86); D001713:Biphenyl Compounds; D009596:Nitrophenols; D010446:Peptide Fragments; D010879:Piperazines; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D013449:Sulfonamides; D045304:Cytochromes c; D006072:Gossypol; C028178:gossypol acetic acid