title: APR-246 potently inhibits tumour growth and overcomes chemoresistance in preclinical models of oesophageal adenocarcinoma.
abstract: OBJECTIVE
  p53 is a critical tumour suppressor and is mutated in 70% of oesophageal adenocarcinomas (OACs), resulting in chemoresistance and poor survival. APR-246 is a first-in-class reactivator of mutant p53 and is currently in clinical trials. In this study, we characterised the activity of APR-246 and its effect on p53 signalling in a large panel of cell line xenograft (CLX) and patient-derived xenograft (PDX) models of OAC.
  
  
  METHODS
  In vitro response to APR-246 was assessed using clonogenic survival, cell cycle and apoptosis assays. Ectopic expression, gene knockdown and CRISPR/Cas9-mediated knockout studies of mutant p53 were performed to investigate p53-dependent drug effects. p53 signalling was examined using quantitative RT-PCR and western blot. Synergistic interactions between APR-246 and conventional chemotherapies were evaluated in vitro and in vivo using CLX and PDX models.
  
  
  RESULTS
  APR-246 upregulated p53 target genes, inhibited clonogenic survival and induced cell cycle arrest as well as apoptosis in OAC cells harbouring p53 mutations. Sensitivity to APR-246 correlated with cellular levels of mutant p53 protein. Ectopic expression of mutant p53 sensitised p53-null cells to APR-246, while p53 gene knockdown and knockout diminished drug activity. Importantly, APR-246 synergistically enhanced the inhibitory effects of cisplatin and 5-fluorouracil through p53 accumulation. Finally, APR-246 demonstrated potent antitumour activity in CLX and PDX models, and restored chemosensitivity to a cisplatin/5-fluorouracil-resistant xenograft model.
  
  
  CONCLUSIONS
  APR-246 has significant antitumour activity in OAC. Given that APR-246 is safe at therapeutic levels our study strongly suggests that APR-246 can be translated into improving the clinical outcomes for OAC patients.
authors.affiliation: Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: David S H
authors.initials: DS
authors.lastname: Liu
authors.affiliation: Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Read
authors.affiliation: Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Carleen
authors.initials: C
authors.lastname: Cullinane
authors.affiliation: Cancer Genetics and Genomics Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Walid J
authors.initials: WJ
authors.lastname: Azar
authors.affiliation: Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Fennell
authors.affiliation: Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Karen G
authors.initials: KG
authors.lastname: Montgomery
authors.affiliation: Tumour Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Sue
authors.initials: S
authors.lastname: Haupt
authors.affiliation: Tumour Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Ygal
authors.initials: Y
authors.lastname: Haupt
authors.affiliation: Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Klas G
authors.initials: KG
authors.lastname: Wiman
authors.affiliation: Division of Cancer Surgery, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Cuong P
authors.initials: CP
authors.lastname: Duong
authors.affiliation: Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Clemons
authors.affiliation: Surgical Oncology Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia Division of Cancer Surgery, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia University of Melbourne Department of Surgery, St. Vincent's Hospital, Melbourne, Victoria, Australia.
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Phillips
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D009374:Neoplasms, Experimental; D011812:Quinuclidines / Q000627:therapeutic use*; D012334:RNA, Neoplasm / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism
chemical_list: D011812:Quinuclidines; D012334:RNA, Neoplasm; D016159:Tumor Suppressor Protein p53; C533410:eprenetapopt
keywords: DRUG DEVELOPMENT; OESOPHAGEAL CANCER; ONCOGENES