title: Measurement of conatumumab-induced apoptotic activity in tumors by fine needle aspirate sampling.
abstract: Conatumumab is a monoclonal antibody specific for death receptor 5 (DR5) that activates caspases leading to DNA fragmentation and tumor-cell death. Like other Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) receptor therapies, conatumumab is currently being evaluated in clinical trials across a variety of tumor types. However, molecular evidence of on-target drug activity in tumors is often an elusive goal for clinical investigation. Here we evaluated a translational approach using a relevant biopsy method, fine needle aspirates (FNAs), to study the on-target pharmacodynamics of conatumumab pre-clinically. As detected by laser scanning cytometry, drug-induced caspase-3 activation in FNA biopsies of Colo205 xenografts correlated well with activated caspase-3 in conventional section-based samples. Furthermore, in tumor-bearing mice, surrogate assays of serum caspase-3/7 activity and serum drug exposure correlated with in situ caspase-3 activation. We found that one advantage of FNA sampling over other sampling techniques was the ability to measure caspase activity on a per cell basis using DNA content information. To adapt the utility of FNAs for measuring pharmacodynamic markers in humans, detection of activated caspase-3 was multiplexed with EpCAM to characterize mock and clinical FNAs from colorectal and nonsmall cell lung cancer patients. These data suggest that FNA sampling is a practical method to cytometrically evaluate tumors for pharmacological impact in a clinical setting.
authors.affiliation: Department of Clinical Immunology, Amgen Inc., Thousand Oaks, California, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Zoog
authors.forename: Connie Y
authors.initials: CY
authors.lastname: Ma
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Kaplan-Lefko
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Hawkins
authors.forename: Jodi
authors.initials: J
authors.lastname: Moriguchi
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Yang
authors.initials: Y
authors.lastname: Pan
authors.forename: Cheng-Pang
authors.initials: CP
authors.lastname: Hsu
authors.forename: Greg
authors.initials: G
authors.lastname: Friberg
authors.forename: Roy
authors.initials: R
authors.lastname: Herbst
authors.forename: John
authors.initials: J
authors.lastname: Hill
authors.forename: Gloria
authors.initials: G
authors.lastname: Juan
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis; D044963:Biopsy, Fine-Needle; D053148:Caspase 3 / Q000032:analysis*; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D051379:Mice; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000037:antagonists & inhibitors*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; C554537:conatumumab; D053148:Caspase 3