title: Contributions of KRAS and RAL in non-small-cell lung cancer growth and progression.
abstract: BACKGROUND
  KRAS mutations are poor prognostic markers for patients with non-small-cell lung cancer (NSCLC). RALA and RALB GTPases lie downstream of RAS and are implicated in RAS-mediated tumorigenesis. However, their biological or prognostic role in the context of KRAS mutation in NSCLC is unclear.
  
  
  METHODS
  Using expression analysis of human tumors and a panel of cell lines coupled with functional in vivo and in vitro experiments, we evaluated the prognostic and functional importance of RAL in NSCLC and their relationship to KRAS expression and mutation.
  
  
  RESULTS
  Immunohistochemical (N = 189) and transcriptomic (N = 337) analyses of NSCLC patients revealed high RALA and RALB expression was associated with poor survival. In a panel of 14 human NSCLC cell lines, RALA and RALB had higher expression in KRAS mutant cell lines whereas RALA but not RALB activity was higher in KRAS mutant cell lines. Depletion of RAL paralogs identified cell lines that are dependent on RAL expression for proliferation and anchorage independent growth. Overall, growth of NSCLC cell lines that carry a glycine to cystine KRAS mutation were more sensitive to RAL depletion than those with wild-type KRAS. The use of gene expression and outcome data from 337 human tumors in RAL-KRAS interaction analysis revealed that KRAS and RAL paralog expression jointly impact patient prognosis.
  
  
  CONCLUSIONS
  RAL GTPase expression carries important additional prognostic information to KRAS status in NSCLC patients. Simultaneously targeting RAL may provide a novel therapeutic approach in NSCLC patients harboring glycine to cystine KRAS mutations.
authors.affiliation: Departments of *Surgery, †Pharmacology, ‖Biostatistics and Informatics, #Pathology, and ‡Division of Medical Oncology, University of Colorado, Aurora, Colorado; ¶University of Colorado Comprehensive Cancer Center, Aurora, Colorado; and §Department of Medicine, National Jewish Health, Denver, Colorado.
authors.forename: Sunny
authors.initials: S
authors.lastname: Guin
authors.forename: Yuanbin
authors.initials: Y
authors.lastname: Ru
authors.forename: Murry W
authors.initials: MW
authors.lastname: Wynes
authors.forename: Rangnath
authors.initials: R
authors.lastname: Mishra
authors.forename: Xian
authors.initials: X
authors.lastname: Lu
authors.forename: Charles
authors.initials: C
authors.lastname: Owens
authors.forename: Anna E
authors.initials: AE
authors.lastname: Barn
authors.forename: Vihas T
authors.initials: VT
authors.lastname: Vasu
authors.forename: Fred R
authors.initials: FR
authors.lastname: Hirsch
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kern
authors.forename: Dan
authors.initials: D
authors.lastname: Theodorescu
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D009367:Neoplasm Staging; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras); D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D020725:ral GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C483163:Ralb protein, human; C492198:RALA protein, human; D016283:Proto-Oncogene Proteins p21(ras); D020725:ral GTP-Binding Proteins; D018631:ras Proteins