title: Dynamic modulation of phosphoprotein expression in ovarian cancer xenograft models.
abstract: BACKGROUND
  The dynamic changes that occur in protein expression after treatment of a cancer in vivo are poorly described. In this study we measure the effect of chemotherapy over time on the expression of a panel of proteins in ovarian cancer xenograft models. The objective was to identify phosphoprotein and other protein changes indicative of pathway activation that might link with drug response.
  
  
  METHODS
  Two xenograft models, platinum-responsive OV1002 and platinum-unresponsive HOX424, were used. Treatments were carboplatin and carboplatin-paclitaxel. Expression of 49 proteins over 14 days post treatment was measured by quantitative immunofluorescence and analysed by AQUA.
  
  
  RESULTS
  Carboplatin treatment in the platinum-sensitive OV1002 model triggered up-regulation of cell cycle, mTOR and DDR pathways, while at late time points WNT, invasion, EMT and MAPK pathways were modulated. Estrogen receptor-alpha (ESR1) and ERBB pathways were down-regulated early, within 24 h from treatment administration. Combined carboplatin-paclitaxel treatment triggered a more extensive response in the OV1002 model modulating expression of 23 of 49 proteins. Therefore the cell cycle and DDR pathways showed similar or more pronounced changes than with carboplatin alone. In addition to expression of pS6 and pERK increasing, components of the AKT pathway were modulated with pAKT increasing while its regulator PTEN was down-regulated early. WNT signaling, EMT and invasion markers were modulated at later time points. Additional pathways were also observed with the NFκB and JAK/STAT pathways being up-regulated. ESR1 was down-regulated as was HER4, while further protein members of the ERBB pathway were upregulated late. By contrast, in the carboplatin-unresponsive HOX 424 xenograft, carboplatin only modulated expression of MLH1 while carboplatin-paclitaxel treatment modulated ESR1 and pMET.
  
  
  CONCLUSIONS
  Thirteen proteins were modulated by carboplatin and a more robust set of changes by carboplatin-paclitaxel. Early changes included DDR and cell cycle regulatory proteins associating with tumor volume changes, as expected. Changes in ESR1 and ERBB signaling were also observed. Late changes included components of MAPK signaling, EMT and invasion markers and coincided in time with reversal in tumor volume reduction. These results suggest potential therapeutic roles for inhibitors of such pathways that may prolong chemotherapeutic effects.
authors.affiliation: School of Biology, Sir Harold Mitchell Building, University of St Andrews, St Andrews, Fife, KY16 9TH, UK.
authors.forename: Antonis
authors.initials: A
authors.lastname: Koussounadis
authors.affiliation: Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Langdon
authors.affiliation: Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.|School of Medicine, University of St Andrews, St Andrews, UK.
authors.forename: Inhwa
authors.initials: I
authors.lastname: Um
authors.affiliation: Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.
authors.forename: Charlene
authors.initials: C
authors.lastname: Kay
authors.affiliation: Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.
authors.forename: Kyle E
authors.initials: KE
authors.lastname: Francis
authors.affiliation: School of Medicine, University of St Andrews, St Andrews, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Harrison
authors.affiliation: School of Biology, Sir Harold Mitchell Building, University of St Andrews, St Andrews, Fife, KY16 9TH, UK. anne.smith@st-andrews.ac.uk.
authors.forename: V Anne
authors.initials: VA
authors.lastname: Smith
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols; D017209:Apoptosis / Q000187:drug effects; D016190:Carboplatin / Q000008:administration & dosage; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051379:Mice; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D017239:Paclitaxel / Q000008:administration & dosage; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics; D011379:Prognosis; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000096:biosynthesis; D023041:Xenograft Model Antitumor Assays
chemical_list: D009363:Neoplasm Proteins; D010750:Phosphoproteins; D016190:Carboplatin; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D017239:Paclitaxel
keywords: Carboplatin; Ovarian cancer; Paclitaxel; Phosphoproteins; Prognosis; Xenograft