title: Molecular imaging of aurora kinase A (AURKA) expression: Synthesis and preclinical evaluation of radiolabeled alisertib (MLN8237).
abstract: BACKGROUND
  Survival of patients after resection of colorectal cancer liver metastasis (CRCLM) is 36%-58%. Positron emission tomography (PET) tracers, imaging the expression of prognostic biomarkers, may contribute to assign appropriate management to individual patients. Aurora kinase A (AURKA) expression is associated with survival of patients after CRCLM resection.
  
  
  METHODS
  We synthesized [(3)H]alisertib and [(11)C]alisertib, starting from [(3)H]methyl nosylate and [(11)C]methyl iodide, respectively. We measured in vitro uptake of [(3)H]alisertib in cancer cells with high (Caco2), moderate (A431, HCT116, SW480) and low (MKN45) AURKA expression, before and after siRNA-mediated AURKA downmodulation, as well as after inhibition of P-glycoprotein (P-gp) activity. We measured in vivo uptake and biodistribution of [(11)C]alisertib in nude mice, xenografted with A431, HCT116 or MKN45 cells, or P-gp knockout mice.
  
  
  RESULTS
  [(3)H]Alisertib was synthesized with an overall yield of 42% and [(11)C]alisertib with an overall yield of 23%±9% (radiochemical purity ≥99%). Uptake of [(3)H]alisertib in Caco2 cells was higher than in A431 cells (P=.02) and higher than in SW480, HCT116 and MKN45 cells (P<.01). Uptake in A431 cells was higher than in SW480, HCT116 and MKN45 cells (P<.01). Downmodulation of AURKA expression reduced [(3)H]alisertib uptake in Caco2 cells (P<.01). P-gp inhibition increased [(3)H]alisertib uptake in Caco2 (P<.01) and MKN45 (P<.01) cells. In vivo stability of [(11)C]alisertib 90min post-injection was 94.7%±1.3% and tumor-to-background ratios were 2.3±0.8 (A431), 1.6±0.5 (HCT116) and 1.9±0.5 (MKN45). In brains of P-gp knockout mice [(11)C]alisertib uptake was increased compared to uptake in wild-type mice (P<.01) CONCLUSIONS: Radiolabeled alisertib can be synthesized and may have potential for the imaging of AURKA, particularly when AURKA expression is high. However, the exact mechanisms underlying alisertib accumulation need further investigation.
  
  
  CONCLUSIONS
  Radiolabeled alisertib may be used for non-invasively measuring AURKA protein expression and to stratify patients for treatment accordingly.
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands. Electronic address: ja.goos@vumc.nl.
authors.forename: Jeroen A C M
authors.initials: JACM
authors.lastname: Goos
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Joost
authors.initials: J
authors.lastname: Verbeek
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Albert A
authors.initials: AA
authors.lastname: Geldof
authors.affiliation: Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Annemieke C
authors.initials: AC
authors.lastname: Hiemstra
authors.affiliation: Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Mark A
authors.initials: MA
authors.lastname: van de Wiel
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Adamzek
authors.affiliation: Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Pien M
authors.initials: PM
authors.lastname: Delis-Van Diemen
authors.affiliation: Takeda Pharmaceuticals International Co., Boston, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Stroud
authors.affiliation: Takeda Pharmaceuticals International Co., Boston, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Bradley
authors.affiliation: Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands; Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Gerrit A
authors.initials: GA
authors.lastname: Meijer
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Otto S
authors.initials: OS
authors.lastname: Hoekstra
authors.affiliation: Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands; Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Remond J A
authors.initials: RJA
authors.lastname: Fijneman
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Albert D
authors.initials: AD
authors.lastname: Windhorst
mesh_terms: D000818:Animals; D064096:Aurora Kinase A / Q000378:metabolism*; D001381:Azepines / Q000138:chemical synthesis* / Q000378:metabolism / Q000493:pharmacokinetics; D001692:Biological Transport; D045744:Cell Line, Tumor; D060326:Chemistry Techniques, Synthetic; D015179:Colorectal Neoplasms / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007553:Isotope Labeling; D008113:Liver Neoplasms / Q000556:secondary; D051379:Mice; D049268:Positron-Emission Tomography / Q000379:methods*; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000378:metabolism / Q000493:pharmacokinetics; D014018:Tissue Distribution
chemical_list: D001381:Azepines; C550258:MLN 8237; D011743:Pyrimidines; D064096:Aurora Kinase A
keywords: AURKA; Alisertib; Carbon-11; PET; Tritium