title: Regulation of HIF1α under Hypoxia by APE1/Ref-1 Impacts CA9 Expression: Dual Targeting in Patient-Derived 3D Pancreatic Cancer Models.
abstract: Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related mortality in the United States. Aggressive treatment regimens have not changed the disease course, and the median survival has just recently reached a year. Several mechanisms are proposed to play a role in PDAC therapeutic resistance, including hypoxia, which creates a more aggressive phenotype with increased metastatic potential and impaired therapeutic efficacy. AP Endonuclease-1/Redox Effector Factor 1 (APE1/Ref-1) is a multifunctional protein possessing a DNA repair function in base excision repair and the ability to reduce oxidized transcription factors, enabling them to bind to their DNA target sequences. APE1/Ref-1 regulates several transcription factors involved in survival mechanisms, tumor growth, and hypoxia signaling. Here, we explore the mechanisms underlying PDAC cell responses to hypoxia and modulation of APE1/Ref-1 redox signaling activity, which regulates the transcriptional activation of hypoxia-inducible factor 1 alpha (HIF1α). Carbonic anhydrase IX (CA9) is regulated by HIF1α and functions as a part of the cellular response to hypoxia to regulate intracellular pH, thereby promoting cell survival. We hypothesized that modulating APE1/Ref-1 function will block activation of downstream transcription factors, STAT3 and HIF1α, interfering with the hypoxia-induced gene expression. We demonstrate APE1/Ref-1 inhibition in patient-derived and established PDAC cells results in decreased HIF1α-mediated induction of CA9. Furthermore, an ex vivo three-dimensional tumor coculture model demonstrates dramatic enhancement of APE1/Ref-1-induced cell killing upon dual targeting of APE1/Ref-1 and CA9. Both APE1/Ref-1 and CA9 are under clinical development; therefore, these studies have the potential to direct novel PDAC therapeutic treatment. Mol Cancer Ther; 15(11); 2722-32. ©2016 AACR.
authors.affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Derek P
authors.initials: DP
authors.lastname: Logsdon
authors.affiliation: Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Michelle
authors.initials: M
authors.lastname: Grimard
authors.affiliation: Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Meihua
authors.initials: M
authors.lastname: Luo
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.|Pancreatic Cancer Signature Center, Indianapolis, Indiana.
authors.forename: Safi
authors.initials: S
authors.lastname: Shahda
authors.affiliation: Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Yan
authors.initials: Y
authors.lastname: Tong
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Zhangsheng
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Pancreatic Cancer Signature Center, Indianapolis, Indiana.|Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Zyromski
authors.affiliation: Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan.
authors.forename: Ernestina
authors.initials: E
authors.lastname: Schipani
authors.affiliation: Neurofarba Department, Section of Medicinal Chemistry, University of Florence, Florence, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Carta
authors.affiliation: Neurofarba Department, Section of Medicinal Chemistry, University of Florence, Florence, Italy.
authors.forename: Claudiu T
authors.initials: CT
authors.lastname: Supuran
authors.affiliation: Pancreatic Cancer Signature Center, Indianapolis, Indiana.|Division of Endocrinology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.|Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Murray
authors.initials: M
authors.lastname: Korc
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.|Pancreatic Cancer Signature Center, Indianapolis, Indiana.|Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Mircea
authors.initials: M
authors.lastname: Ivan
authors.affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana.|Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.|Pancreatic Cancer Signature Center, Indianapolis, Indiana.|Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Kelley
authors.affiliation: Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana. mfishel@iu.edu.|Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.|Pancreatic Cancer Signature Center, Indianapolis, Indiana.
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Fishel
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D000071231:Carbonic Anhydrase IX / Q000235:genetics*; D021441:Carcinoma, Pancreatic Ductal / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D000860:Hypoxia / Q000235:genetics / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D011485:Protein Binding; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D018874:Spheroids, Cellular; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D050796:STAT3 Transcription Factor; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase