title: SLC1A5 mediates glutamine transport required for lung cancer cell growth and survival.
abstract: OBJECTIVE
  We have previously identified solute-linked carrier family A1 member 5 (SLC1A5) as an overexpressed protein in a shotgun proteomic analysis of stage I non-small cell lung cancer (NSCLC) when compared with matched controls. We hypothesized that overexpression of SLC1A5 occurs to meet the metabolic demand for lung cancer cell growth and survival.
  
  
  METHODS
  To test our hypothesis, we first analyzed the protein expression of SLC1A5 in archival lung cancer tissues by immunohistochemistry and immunoblotting (N = 98) and in cell lines (N = 36). To examine SLC1A5 involvement in amino acid transportation, we conducted kinetic analysis of l-glutamine (Gln) uptake in lung cancer cell lines in the presence and absence of a pharmacologic inhibitor of SLC1A5, gamma-l-Glutamyl-p-Nitroanilide (GPNA). Finally, we examined the effect of Gln deprivation and uptake inhibition on cell growth, cell-cycle progression, and growth signaling pathways of five lung cancer cell lines.
  
  
  RESULTS
  Our results show that (i) SLC1A5 protein is expressed in 95% of squamous cell carcinomas (SCC), 74% of adenocarcinomas (ADC), and 50% of neuroendocrine tumors; (ii) SLC1A5 is located at the cytoplasmic membrane and is significantly associated with SCC histology and male gender; (iii) 68% of Gln is transported in a Na(+)-dependent manner, 50% of which is attributed to SLC1A5 activity; and (iv) pharmacologic and genetic targeting of SLC1A5 decreased cell growth and viability in lung cancer cells, an effect mediated in part by mTOR signaling.
  
  
  CONCLUSIONS
  These results suggest that SLC1A5 plays a key role in Gln transport controlling lung cancer cells' metabolism, growth, and survival.
authors.affiliation: Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Jim Ayers Institute of Precancer Detection and Diagnosis, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hassanein
authors.forename: Megan D
authors.initials: MD
authors.lastname: Hoeksema
authors.forename: Masakazu
authors.initials: M
authors.lastname: Shiota
authors.forename: Jun
authors.initials: J
authors.lastname: Qian
authors.forename: Bradford K
authors.initials: BK
authors.lastname: Harris
authors.forename: Heidi
authors.initials: H
authors.lastname: Chen
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Clark
authors.forename: William E
authors.initials: WE
authors.lastname: Alborn
authors.forename: Rosana
authors.initials: R
authors.lastname: Eisenberg
authors.forename: Pierre P
authors.initials: PP
authors.lastname: Massion
mesh_terms: D000328:Adult; D000368:Aged; D026962:Amino Acid Transport System ASC / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D005260:Female; D059585:G1 Phase Cell Cycle Checkpoints; D015870:Gene Expression; D005973:Glutamine / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015778:Minor Histocompatibility Antigens; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D012737:Sex Factors; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D026962:Amino Acid Transport System ASC; D015778:Minor Histocompatibility Antigens; D017382:Reactive Oxygen Species; C420506:SLC1A5 protein, human; D005973:Glutamine; D058570:TOR Serine-Threonine Kinases