title: Visceral obesity stimulates anaphase bridge formation and spindle assembly checkpoint dysregulation in radioresistant oesophageal adenocarcinoma.
abstract: OBJECTIVE
  Oesophageal adenocarcinoma is an exemplar model of obesity-associated cancer. Locally advanced disease is treated with neoadjuvant chemoradiotherapy, and survival rates are highest in patients demonstrating a pathological response following neoadjuvant therapy. Given that 55 % of oesophageal adenocarcinoma patients are obese, uncovering the effect of adipose tissue on radioresponse is clinically relevant. This study investigates if adipose tissue activates genomic instability events in radioresponsive (OE33P) and radioresistant (OE33R) oesophageal cancer cell lines and tumour samples.
  
  
  METHODS
  OE33R and OE33P were cultured with adipose-conditioned media derived from oesophageal adenocarcinoma patients (n = 10). Anaphase bridges, a marker of genomic instability, were enumerated in both cell lines following treatment with adipose media, and normalised to cell number. Genomic instability is regulated by the spindle assembly complex. Expression of two spindle assembly complex genes (MAD2L2, BUB1B) was assessed using qPCR, and validated in patient tumour specimens from viscerally obese (n = 46) and nonobese patients (n = 41).
  
  
  RESULTS
  Adipose-conditioned media increased anaphase bridging in OE33R (p < 0.0001), with a threefold increase in OE33R compared to OE33P (p < 0.01). Levels of anaphase bridges in OE33R cells correlated with visceral obesity status as measured by waist circumference (R = 0.709, p = 0.03) and visceral fat area (R = 0.794, p = 0.006). Adipose tissue altered expression of MAD2L2 in vitro. In vivo, MAD2L2 expression was higher in viscerally obese oesophageal adenocarcinoma patients compared with nonobese patients (p < 0.05).
  
  
  CONCLUSIONS
  Anaphase bridge levels are influenced by obesity and radiosensitivity status in oesophageal adenocarcinoma. Furthermore, visceral adipose-conditioned media stimulates dysregulation of the spindle assembly complex in oesophageal adenocarcinoma patients.
authors.affiliation: Department of Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
authors.forename: A M
authors.initials: AM
authors.lastname: Mongan
authors.affiliation: Department of Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: Lynam-Lennon
authors.affiliation: Department of Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
authors.forename: R
authors.initials: R
authors.lastname: Casey
authors.affiliation: Cancer Biology & Therapeutics Lab, School of Biological, Biomedical & Environmental Sciences, University of Hull, Cottingham road, Hull, HU6 76X, UK.
authors.forename: S
authors.initials: S
authors.lastname: Maher
authors.affiliation: Department of Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
authors.forename: G
authors.initials: G
authors.lastname: Pidgeon
authors.affiliation: Department of Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
authors.forename: J V
authors.initials: JV
authors.lastname: Reynolds
authors.affiliation: Department of Surgery, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland. osullij4@tcd.ie.
authors.forename: J
authors.initials: J
authors.lastname: O'Sullivan
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology*; D000368:Aged; D000705:Anaphase / Q000235:genetics; D018797:Cell Cycle Proteins / Q000032:analysis / Q000096:biosynthesis; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000473:pathology; D004938:Esophageal Neoplasms / Q000235:genetics / Q000473:pathology*; D042822:Genomic Instability; D006801:Humans; D059566:M Phase Cell Cycle Checkpoints / Q000235:genetics; D064246:Mad2 Proteins / Q000032:analysis / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000150:complications*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000096:biosynthesis; D011836:Radiation Tolerance / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: C584279:BUB1B protein, human; D018797:Cell Cycle Proteins; C120552:MAD2L2 protein, human; D064246:Mad2 Proteins; D017346:Protein Serine-Threonine Kinases
keywords: Genomic instability; Obesity; Oesophageal cancer; Radiotherapy