title: Thin-layer chromatography/matrix-assisted laser desorption/ionisation mass spectrometry and matrix-assisted laser desorption/ionisation mass spectrometry imaging for the analysis of phospholipids in LS174T colorectal adenocarcinoma xenografts treated with the vascular disrupting agent DMXAA.
abstract: BACKGROUND
  5,6-Dimethylxanthenone-4-acetic acid (DMXAA) is a low molecular weight drug of the flavonoid group, which has an anti-vascular effect in tumours causing endothelial cell apoptosis and activation of cytokines. Flavonoid-based compounds have been reported to lead to an upregulation in the expression of lysophosphatidylcholines (LPC)-type lipids in solid tumours. A study employing TLC/MALDI-MS and MALDI-MS imaging to examine LS174T colorectal adenocarcinoma xenografts following administration of DMXAA has been conducted into this effect.
  
  
  METHODS
  LS174T colorectal adenocarcinoma xenografts grown in male immune-deficient mice were treated with 27.5 mg/kg DMXAA. The control (before treatment) and 4 h and 24 h post-treatment tumours were excised and divided into two. MALDI-MS imaging experiments were carried out on 12 µm cryosections sections taken from one half of the tumours and from the other half the lipids were extracted and analysed by TLC/MALDI-MS. These experiments were carried out in triplicate.
  
  
  RESULTS
  Statistical analysis of the MALDI-MS imaging data set indicated an increased amount of LPC in the 24 h post-treated sample and a decreased amount of PC in the 24 h post-treated sample, compared with the 4 h post-treated sample and the control. These effects were confirmed by the TLC/MALDI-MS data. The lipid extracts were separated into six spots on the TLC plate. These were identified as arising from different lipids classes, i.e. LPC, sphingomyelins (SM), phosphatidylcholines (PC) and phosphatidylethanolamines (PE). The TLC/MALDI-MS data indicated that LPC were highly expressed in the 4 h and 24 h post-treated tumour samples compared with the control. Examination of the mass spectrometric images confirms this increase and demonstrates additionally that the increase in the signals arising from LPC appears to be localised primarily within the central areas of the xenograft.
  
  
  CONCLUSIONS
  An increase in expression of LPC lipids in solid tumours treated with DMXAA has been demonstrated and shown to be localised in the central area of the tumour.
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK.
authors.forename: Afnan
authors.initials: A
authors.lastname: Batubara
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK.
authors.forename: Vikki A
authors.initials: VA
authors.lastname: Carolan
authors.affiliation: Institute of Cancer Therapeutics, University of Bradford, Bradford, BD7 1DP, UK.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Loadman
authors.affiliation: Institute of Cancer Therapeutics, University of Bradford, Bradford, BD7 1DP, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Sutton
authors.affiliation: Institute of Cancer Therapeutics, University of Bradford, Bradford, BD7 1DP, UK.
authors.forename: Steve D
authors.initials: SD
authors.lastname: Shnyder
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK.
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Clench
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002855:Chromatography, Thin Layer / Q000379:methods; D003106:Colon / Q000187:drug effects / Q000473:pathology; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D010743:Phospholipids / Q000032:analysis*; D012007:Rectum / Q000187:drug effects / Q000473:pathology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D044004:Xanthones / Q000627:therapeutic use*
chemical_list: D000970:Antineoplastic Agents; D010743:Phospholipids; D044004:Xanthones; C066668:vadimezan