Treating metastatic solid tumors with bortezomib and a tumor necrosis factor-related apoptosis-inducing ligand receptor agonist antibody.

Abstract

BACKGROUND: Resistance of tumors to cell death signals poses a complex clinical problem. We explored the therapeutic potential and in vivo toxicity of a combination of bortezomib, a proteasome inhibitor, and MD5-1, a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor (DR5) agonist monoclonal antibody, in mouse carcinomas. METHODS; Mice bearing Renca-FLAG (renal) or 4T1 (mammary) tumors were treated with bortezomib and/or MD5-1 and examined for lung metastases (Renca-FLAG: n = 93; 4T1: n = 40) or monitored for survival (Renca-FLAG: n = 143). Toxicity was assessed by histopathology and hematology. Viability and apoptotic signaling in Renca-FLAG and 4T1 cells treated with bortezomib alone or in combination with TRAIL were analyzed using 3-[4,5-dimethyiazol-2-yl-5]-[3-carboxymethyloxyphenyl]-2-[4-sulfophenyl]-2H tetrazolium assay and by measuring mitochondrial membrane depolarization and caspase-8 and caspase-3 activation. All statistical tests were two-sided. RESULTS: Bortezomib (20 nM) sensitized Renca-FLAG and 4T1 cells to TRAIL-mediated apoptosis (mean percent decrease in numbers of viable cells, bortezomib + TRAIL vs TRAIL: Renca-FLAG, 95% vs 34%, difference = 61%, 95% confidence interval [CI] = 52% to 69%, P < .001; 4T1, 85% vs 20%, difference = 65%, 95% CI = 62% to 69%, P < .001). Sensitization involved activation of caspase-8 and caspase-3 but not mitochondrial membrane depolarization, suggesting an amplified signaling of the extrinsic cell death pathway. Treatment with bortezomib and MD5-1 reduced lung metastases in mice carrying Renca and 4T1 tumors (mean number of metastases, bortezomib + MD5-1 vs MD5-1: Renca-FLAG, 1 vs 8, difference = 7, 95% CI = 5 to 9, P < .001; 4T1, 1 vs 12, difference = 11, 95% CI = 9 to 12, P < .001) and increased median survival of mice bearing Renca-FLAG tumors (bortezomib + MD5-1 vs bortezomib + control isotype antibody: 22 of 30 [73%] were still alive at day 180 vs median survival of 42 days [95% CI = 41 to 44 days, P < .001]) in the absence of obvious toxicity. CONCLUSION: Bortezomib combined with DR5 agonist monoclonal antibody may be a useful treatment for metastatic solid tumors.

Authors

Shanker, Anil; Brooks, Alan David; Tristan, Carlos Alberto; Wine, John William; Elliott, Peter John; Yagita, Hideo; Takeda, Kazuyoshi; Smyth, Mark John; Murphy, William Joseph; Sayers, Thomas Joseph;

Keywords

  • Adenocarcinoma/ drug therapy
  • Adenocarcinoma/ secondary
  • Animals
  • Antibodies, Monoclonal/ pharmacology
  • Antineoplastic Agents/ administration & dosage
  • Antineoplastic Agents/ adverse effects
  • Antineoplastic Agents/ pharmacology
  • Apoptosis/ drug effects
  • Boronic Acids/ pharmacology
  • Bortezomib
  • Caspase 3/ metabolism
  • Caspase 8/ metabolism
  • Cell Line, Tumor
  • Cell Survival/ drug effects
  • Female
  • Flow Cytometry
  • Humans
  • Immunoblotting
  • Kidney Neoplasms/ drug therapy
  • Kidney Neoplasms/ pathology
  • Lung Neoplasms/ drug therapy
  • Lung Neoplasms/ secondary
  • Mammary Neoplasms, Animal/ drug therapy
  • Mammary Neoplasms, Animal/ secondary
  • Mice
  • Mice, Inbred BALB C
  • Mitochondrial Membranes/ metabolism
  • Protease Inhibitors/ pharmacology
  • Proto-Oncogene Proteins c-bcl-2/ metabolism
  • Pyrazines/ pharmacology
  • Receptors, TNF-Related Apoptosis-Inducing Ligand/ agonists
  • Signal Transduction/ drug effects
  • TNF-Related Apoptosis-Inducing Ligand/ metabolism

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