title: Changes in circulating microRNAs after radiochemotherapy in head and neck cancer patients.
abstract: BACKGROUND
  Circulating microRNAs (miRNAs) are easily accessible and have already proven to be useful as prognostic markers in cancer patients. However, their origin and function in the circulation is still under discussion. In the present study we analyzed changes in the miRNAs in blood plasma of head and neck squamous cell carcinoma (HNSCC) patients in response to radiochemotherapy and compared them to the changes in a cell culture model of primary HNSCC cells undergoing simulated anti-cancer therapy.
  
  
  METHODS
  MiRNA-profiles were analyzed by qRT-PCR arrays in paired blood plasma samples of HNSCC patients before therapy and after two days of treatment. Candidate miRNAs were validated by single qRT-PCR assays. An in vitro radiochemotherapy model using primary HNSCC cell cultures was established to test the possible tumor origin of the circulating miRNAs. Microarray analysis was performed on primary HNSCC cell cultures followed by validation of deregulated miRNAs via qRT-PCR.
  
  
  RESULTS
  Unsupervised clustering of the expression profiles using the six most regulated miRNAs (miR-425-5p, miR-21-5p, miR-106b-5p, miR-590-5p, miR-574-3p, miR-885-3p) significantly (p = 0.012) separated plasma samples collected prior to treatment from plasma samples collected after two days of radiochemotherapy. MiRNA profiling of primary HNSCC cell cultures treated in vitro with radiochemotherapy revealed differentially expressed miRNAs that were also observed to be therapy-responsive in blood plasma of the patients (miR-425-5p, miR-21-5p, miR-106b-5p, miR-93-5p) and are therefore likely to stem from the tumor. Of these candidate marker miRNAs we were able to validate by qRT-PCR a deregulation of eight plasma miRNAs as well as miR-425-5p and miR-93-5p in primary HNSCC cultures after radiochemotherapy.
  
  
  CONCLUSIONS
  Changes in the abundance of circulating miRNAs during radiochemotherapy reflect the therapy response of primary HNSCC cells after an in vitro treatment. Therefore, the responsive miRNAs (miR-425-5p, miR-93-5p) may represent novel biomarkers for therapy monitoring. The prognostic value of this exciting observation requires confirmation using an independent patient cohort that includes clinical follow-up data.
authors.forename: Isolde
authors.initials: I
authors.lastname: Summerer
authors.forename: Maximilian
authors.initials: M
authors.lastname: Niyazi
authors.forename: Kristian
authors.initials: K
authors.lastname: Unger
authors.forename: Adriana
authors.initials: A
authors.lastname: Pitea
authors.forename: Verena
authors.initials: V
authors.lastname: Zangen
authors.forename: Julia
authors.initials: J
authors.lastname: Hess
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Atkinson
authors.forename: Claus
authors.initials: C
authors.lastname: Belka
authors.forename: Simone
authors.initials: S
authors.lastname: Moertl
authors.affiliation: Research Unit Radiation Cytogenetics, Helmholtz Center Munich, Ingolstaedter Landstr 1, 85764, Neuherberg, Germany. zitzelsberger@helmholtz-muenchen.de.
authors.forename: Horst
authors.initials: H
authors.lastname: Zitzelsberger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood; D045744:Cell Line, Tumor; D002470:Cell Survival; D059248:Chemoradiotherapy / Q000379:methods*; D016000:Cluster Analysis; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000235:genetics / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000097:blood* / Q000378:metabolism; D046228:Microarray Analysis; D008875:Middle Aged; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D013234:Stem Cells; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D035683:MicroRNAs