Kenji Okumura1, Shengbing Huang, Frank A Sinicrope. 1. Miles and Shirley Fiterman Center for Digestive Diseases and Division of Oncology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Abstract
PURPOSE: The intrinsic drug resistance of colorectal cancers is related in part to overexpression of prosurvival Bcl-2 family proteins. We determined the effects of ABT-737, a small-molecule inhibitor of Bcl-2/Bcl-xL but not Mcl-1, on apoptosis induction alone and in combination with CPT-11 and explored mechanisms underlying their cooperativity. EXPERIMENTAL DESIGN: Human colorectal carcinoma cell lines (HCT116 wild-type and Bax(-/-), HT-29, and RKO) were incubated with ABT-737 alone and combined with CPT-11 or bortezomib, and cell viability, caspase cleavage, and Annexin V labeling were measured. In drug-treated cell lines, protein-protein interactions were analyzed by immunoprecipitation. Lentiviral short hairpin RNA was used to knockdown Noxa expression. RESULTS: ABT-737 induced apoptosis in a dose-dependent manner and its coadministration with the topoisomerase I inhibitor, CPT-11, resulted in a synergistic cytotoxic effect. Apoptosis induction by the drug combination was associated with enhanced caspase-8, caspase-9, and caspase-3 activation and poly(ADP-ribose) polymerase cleavage that were completely abrogated in Bax knockout cells. ABT-737 unsequestered the BH3-only protein Bim from its complex with Bcl-xL or Bcl-2 and disrupted the interaction of Bcl-xL with Bak. CPT-11 treatment up-regulated Noxa expression, as did bortezomib, and enhanced Noxa/Mcl-1 complexes. CPT-11 also disrupted the Mcl-1/Bak interaction. Knockdown of Noxa using short hairpin RNA lentiviral constructs was shown to significantly attenuate the cytotoxic effect of CPT-11 or bortezomib combined with ABT-737 and inhibited caspase-3 cleavage. CONCLUSIONS: Induction of Noxa by CPT-11 or bortezomib can sensitize colorectal cancer cells expressing Mcl-1 to ABT-737. Up-regulation of Noxa may therefore represent an important strategy to enhance the therapeutic efficacy of ABT-737 against colorectal cancer and other solid tumors.
PURPOSE: The intrinsic drug resistance of colorectal cancers is related in part to overexpression of prosurvival Bcl-2 family proteins. We determined the effects of ABT-737, a small-molecule inhibitor of Bcl-2/Bcl-xL but not Mcl-1, on apoptosis induction alone and in combination with CPT-11 and explored mechanisms underlying their cooperativity. EXPERIMENTAL DESIGN:Humancolorectal carcinoma cell lines (HCT116 wild-type and Bax(-/-), HT-29, and RKO) were incubated with ABT-737 alone and combined with CPT-11 or bortezomib, and cell viability, caspase cleavage, and Annexin V labeling were measured. In drug-treated cell lines, protein-protein interactions were analyzed by immunoprecipitation. Lentiviral short hairpin RNA was used to knockdown Noxa expression. RESULTS:ABT-737 induced apoptosis in a dose-dependent manner and its coadministration with the topoisomerase I inhibitor, CPT-11, resulted in a synergistic cytotoxic effect. Apoptosis induction by the drug combination was associated with enhanced caspase-8, caspase-9, and caspase-3 activation and poly(ADP-ribose) polymerase cleavage that were completely abrogated in Bax knockout cells. ABT-737 unsequestered the BH3-only protein Bim from its complex with Bcl-xL or Bcl-2 and disrupted the interaction of Bcl-xL with Bak. CPT-11 treatment up-regulated Noxa expression, as did bortezomib, and enhanced Noxa/Mcl-1 complexes. CPT-11 also disrupted the Mcl-1/Bak interaction. Knockdown of Noxa using short hairpin RNA lentiviral constructs was shown to significantly attenuate the cytotoxic effect of CPT-11 or bortezomib combined with ABT-737 and inhibited caspase-3 cleavage. CONCLUSIONS: Induction of Noxa by CPT-11 or bortezomib can sensitize colorectal cancer cells expressing Mcl-1 to ABT-737. Up-regulation of Noxa may therefore represent an important strategy to enhance the therapeutic efficacy of ABT-737 against colorectal cancer and other solid tumors.
Authors: Richard L Hayward; Janet S Macpherson; Jeff Cummings; Brett P Monia; John F Smyth; Duncan I Jodrell Journal: Clin Cancer Res Date: 2003-07 Impact factor: 12.531
Authors: Andreas Villunger; Ewa M Michalak; Leigh Coultas; Franziska Müllauer; Gunther Böck; Michael J Ausserlechner; Jerry M Adams; Andreas Strasser Journal: Science Date: 2003-09-18 Impact factor: 47.728
Authors: John Boyer; Estelle G McLean; Somaiah Aroori; Peter Wilson; Andrea McCulla; P Declan Carey; Daniel B Longley; Patrick G Johnston Journal: Clin Cancer Res Date: 2004-03-15 Impact factor: 12.531
Authors: Rozenn Jossé; Scott E Martin; Rajarshi Guha; Pinar Ormanoglu; Thomas D Pfister; Philip M Reaper; Christopher S Barnes; Julie Jones; Peter Charlton; John R Pollard; Joel Morris; James H Doroshow; Yves Pommier Journal: Cancer Res Date: 2014-09-30 Impact factor: 12.701
Authors: Kristen E Olberding; Xiaoli Wang; Yanglong Zhu; Jianmin Pan; Shesh N Rai; Chi Li Journal: Cancer Biol Ther Date: 2010-11-01 Impact factor: 4.742
Authors: Samantha R Oakes; François Vaillant; Elgene Lim; Lily Lee; Kelsey Breslin; Frank Feleppa; Siddhartha Deb; Matthew E Ritchie; Elena Takano; Teresa Ward; Stephen B Fox; Daniele Generali; Gordon K Smyth; Andreas Strasser; David C S Huang; Jane E Visvader; Geoffrey J Lindeman Journal: Proc Natl Acad Sci U S A Date: 2011-07-18 Impact factor: 11.205
Authors: Alejo A Morales; Metin Kurtoglu; Shannon M Matulis; Jiangxia Liu; David Siefker; Delia M Gutman; Jonathan L Kaufman; Kelvin P Lee; Sagar Lonial; Lawrence H Boise Journal: Blood Date: 2011-06-09 Impact factor: 22.113
Authors: M T de Bruijn; D A E Raats; F J H Hoogwater; W J van Houdt; K Cameron; J P Medema; I H M Borel Rinkes; O Kranenburg Journal: Br J Cancer Date: 2010-03-30 Impact factor: 7.640