title: Enhanced choline metabolism in a rodent rhabdomyosarcoma model: correlation between RT-PCR and translational 3 T H-MRS.
abstract: OBJECTIVE
  To investigate which transmembrane choline transporters and intracellular choline kinases play a prominent role at gene expression level in the rise of the total choline (tCho) peak at proton MR spectra in a rodent rhabdomyosarcoma model.
  
  
  METHODS
  Twenty-two rats bearing grafted bilateral syngenic rhabdomyosarcoma were examined on a clinical 3 T MR system. Total choline concentration was measured from proton MR spectra using cubic centimeter volumes of interest (VOIs) located contiguously along the greater axis of the tumour. After euthanasia, cubic centimetre tissue specimens corresponding to Proton magnetic resonance spectroscopy (H-MRS) VOIs were frozen in liquid nitrogen. Out of 89 H-MRS voxels, only 39 with a corresponding tissue specimen suitable for biochemical processing were included in the analysis. RNA was extracted from all the 39 samples and reverse-transcribed into cDNA. Choline kinase α and β gene expression as well as genes of the transmembrane transporters OCT1, OCT2, OCT3, CTL1, CTL3, CTL4 and CHT1 were studied using reverse transcriptase polymerase chain reaction. The expression level of each gene (ΔCt), was normalized referred to that of the RPL19 gene. The Spearman rank correlation coefficient was used to analyse variables.
  
  
  RESULTS
  There was no overexpression of genes coding for kinases; however, significant correlation was observed between kinase α sub-type and the tCho peak (P=.002; r=0.51). OCT1 was the most overexpressed transporter gene. Less overexpressed CTL1 gene was significantly correlated with the tCho peak (P=.02; r=0.38).
  
  
  CONCLUSIONS
  Choline transporters seem to play a predominant role in the increase in total choline concentration at the gene expression level in our model.
authors.affiliation: Department of Radiology and Medical Imaging, Université Catholique de Louvain, Cliniques Universitaires Saint-Luc Av. Hippocrate, 10, 1200 Brussels, Belgium. denis.rommel@uclouvain.be
authors.forename: Denis
authors.initials: D
authors.lastname: Rommel
authors.forename: Jorge
authors.initials: J
authors.lastname: Abarca-Quinones
authors.forename: Christine
authors.initials: C
authors.lastname: De Saeger
authors.forename: Frank
authors.initials: F
authors.lastname: Peeters
authors.forename: Isabelle
authors.initials: I
authors.lastname: Leclercq
authors.forename: Thierry
authors.initials: T
authors.lastname: Duprez
mesh_terms: D000818:Animals; D002794:Choline / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012208:Rhabdomyosarcoma / Q000378:metabolism* / Q000473:pathology*; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
chemical_list: D011522:Protons; D002794:Choline