title: Small molecule XIAP inhibitors enhance TRAIL-induced apoptosis and antitumor activity in preclinical models of pancreatic carcinoma.
abstract: Evasion of apoptosis is a characteristic feature of pancreatic cancer, a prototypic cancer that is refractory to current treatment approaches. Hence, there is an urgent need to design rational strategies that counter apoptosis resistance. To explore X-linked inhibitor of apoptosis (XIAP) as a therapeutic target in pancreatic cancer, we analyzed the expression of XIAP in pancreatic tumor samples and evaluated the effect of small molecule XIAP inhibitors alone and in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) against pancreatic carcinoma in vitro and in vivo. Here, we report that XIAP is highly expressed in pancreatic adenocarcinoma samples compared with normal pancreatic ducts. Small molecule XIAP inhibitors synergize with TRAIL to induce apoptosis and to inhibit long-term clonogenic survival of pancreatic carcinoma cells. In contrast, they do not reverse the lack of toxicity of TRAIL on nonmalignant cells in vitro or normal tissues in vivo, pointing to a therapeutic index. Most importantly, XIAP inhibitors cooperate with TRAIL to trigger apoptosis and suppress pancreatic carcinoma growth in vivo in two preclinical models, i.e., the chorioallantoic membrane model and a mouse xenograft model. Parallel immunohistochemical analysis of tumor tissue under therapy reveals that the XIAP inhibitor acts in concert with TRAIL to cause caspase-3 activation and apoptosis. In conclusion, our findings provide, for the first time, evidence in vivo that XIAP inhibitors prime pancreatic carcinoma cells for TRAIL-induced apoptosis and potentiate the antitumor activity of TRAIL against established pancreatic carcinoma. These findings build the rationale for further (pre)clinical development of XIAP inhibitors and TRAIL against pancreatic cancer.
authors.affiliation: University Children's Hospital, Ulm University, Ulm, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Vogler
authors.forename: Henning
authors.initials: H
authors.lastname: Walczak
authors.forename: Dominic
authors.initials: D
authors.lastname: Stadel
authors.forename: Tobias L
authors.initials: TL
authors.lastname: Haas
authors.forename: Felicitas
authors.initials: F
authors.lastname: Genze
authors.forename: Marjana
authors.initials: M
authors.lastname: Jovanovic
authors.forename: Umesh
authors.initials: U
authors.lastname: Bhanot
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hasel
authors.forename: Peter
authors.initials: P
authors.lastname: Möller
authors.forename: Jürgen E
authors.initials: JE
authors.lastname: Gschwend
authors.forename: Thomas
authors.initials: T
authors.lastname: Simmet
authors.forename: Klaus-Michael
authors.initials: KM
authors.lastname: Debatin
authors.forename: Simone
authors.initials: S
authors.lastname: Fulda
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D021441:Carcinoma, Pancreatic Ductal / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D004357:Drug Synergism; D004789:Enzyme Activation; D005260:Female; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000008:administration & dosage / Q000494:pharmacology*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D023041:Xenograft Model Antitumor Assays
chemical_list: D053221:TNF-Related Apoptosis-Inducing Ligand; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D053148:Caspase 3