title: Common PIK3CA mutants and a novel 3' UTR mutation are associated with increased sensitivity to saracatinib.
abstract: OBJECTIVE
  Dysregulation of the phosphoinositide 3-kinase (PI3K) and Src signaling pathways commonly occur in colorectal cancer. Mutations in the PIK3CA gene are associated with an increase in severity of disease and worse clinical outcomes. Elevated levels of Src have been identified in premalignant lesions and are suggested to play a central role in tumor progression. Because these pathways appear to enhance tumor growth and metastasis, molecularly targeted agents for both pathways are currently being evaluated in early-phase clinical trials.
  
  
  METHODS
  We used colorectal cancer cell lines and a patient-derived explant model to investigate the efficacy of saracatinib. Mutations in the PIK3CA were evaluated to examine the association between mutations in the PIK3CA gene and sensitivity to saracatinib.
  
  
  RESULTS
  We have identified a subset of patients with a PIK3CA (exon 9 and 20) mutation with increased sensitivity to saracatinib. A novel 3' untranslated region (UTR) mutation was also shown to be associated with increased sensitivity to saracatinib and have a reduced affinity for miR-520a and miR-525a. Importantly, we show that Src inhibition reduces the interaction between Src and p85, subsequently decreasing Akt-dependent signaling.
  
  
  CONCLUSIONS
  These results indicate that a personalized approach in targeting Src in PIK3CA-mutant patients with colorectal cancers may prove effective in a subset of patients with this genetic alteration.
authors.affiliation: Division of Medical Oncology, University of Colorado Denver and University of Colorado Cancer Center, Denver, Colorado 80045, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Arcaroli
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Quackenbush
authors.forename: Rebecca W
authors.initials: RW
authors.lastname: Powell
authors.forename: Todd M
authors.initials: TM
authors.lastname: Pitts
authors.forename: Anna
authors.initials: A
authors.lastname: Spreafico
authors.forename: Marileila
authors.initials: M
authors.lastname: Varella-Garcia
authors.forename: Lynne
authors.initials: L
authors.lastname: Bemis
authors.forename: Aik Choon
authors.initials: AC
authors.lastname: Tan
authors.forename: Jaclyn M
authors.initials: JM
authors.lastname: Reinemann
authors.forename: Basel M
authors.initials: BM
authors.lastname: Touban
authors.forename: Arvind
authors.initials: A
authors.lastname: Dasari
authors.forename: S Gail
authors.initials: SG
authors.lastname: Eckhardt
authors.forename: Wells A
authors.initials: WA
authors.lastname: Messersmith
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics*; D000818:Animals; D052117:Benzodioxoles / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D058534:Class I Phosphatidylinositol 3-Kinases; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D018628:Gene Dosage; D020869:Gene Expression Profiling; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D051379:Mice; D035683:MicroRNAs / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics* / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D052117:Benzodioxoles; D014408:Biomarkers, Tumor; D035683:MicroRNAs; D011799:Quinazolines; C515233:saracatinib; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human; D019061:src-Family Kinases; D051059:PTEN Phosphohydrolase