title: IL-27 inhibits epithelial-mesenchymal transition and angiogenic factor production in a STAT1-dominant pathway in human non-small cell lung cancer.
abstract: BACKGROUND
  Interleukin-27 signaling is mediated by the JAK-STAT pathway via activation of STAT1 and STAT3, which have tumor suppressive and oncogenic activities, respectively. Epithelial-mesenchymal transition (EMT) and angiogenesis are key processes in carcinogenesis. Although IL-27 has been shown to have potent anti-tumor activity in various cancer models, the role of IL-27 in EMT and angiogenesis is poorly understood. In this study, we investigated the role of IL-27 in regulating EMT and angiogenesis through modulation of the STAT pathways in human non-small cell lung carcinoma (NSCLC) cells.
  
  
  METHODS
  STAT activation following IL-27 exposure was measured in human NSCLC cell lines. Expression of epithelial (E-cadherin, γ-catenin) and mesenchymal (N-cadherin, vimentin) markers were assessed by Western blot analysis. Production of pro-angiogenic factors (VEGF, IL-8/CXCL8, CXCL5) were examined by ELISA. Cell motility was examined by an in vitro scratch and transwell migration assays. Selective inhibitors of STAT1 (STAT1 siRNAs) and STAT3 (Stattic) were used to determine whether both STAT1 and STAT3 are required for IL-27 mediated inhibition of EMT and secretion of angiogenic factors.
  
  
  RESULTS
  Our results demonstrate that IL-27 stimulation in NSCLC resulted in 1) STAT1 and STAT3 activation in a JAK-dependent manner, 2) development of epithelial phenotypes, including a decrease in the expression of a transcriptional repressor for E-cadherin (SNAIL), and mesenchymal marker (vimentin) with a reciprocal increase in the expression of epithelial markers, 3) inhibition of cell migration, and 4) reduced production of pro-angiogenic factors. STAT1 inhibition in IL-27-treated cells reversed the IL-27 effect with resultant increased expression of Snail, vimentin and the pro-angiogenic factors. The inhibition of STAT3 activation had no effect on the development of the epithelial phenotype.
  
  
  CONCLUSIONS
  IL-27 induces mesenchymal to epithelial transition and inhibits the production of pro-angiogenic factors in a STAT1-dominant pathway. These findings highlight the importance of STAT1 in repressing lung carcinogenesis and describe a new anti-tumor mechanism of IL-27.
authors.affiliation: Lung Cancer Research Program, Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA. jaymoonlee@mednet.ucla.edu.
authors.forename: Puja
authors.initials: P
authors.lastname: Kachroo
authors.forename: Mi-Heon
authors.initials: MH
authors.lastname: Lee
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Felicita
authors.initials: F
authors.lastname: Baratelli
authors.forename: Gina
authors.initials: G
authors.lastname: Lee
authors.forename: Minu K
authors.initials: MK
authors.lastname: Srivastava
authors.forename: Gerald
authors.initials: G
authors.lastname: Wang
authors.forename: Tonya C
authors.initials: TC
authors.lastname: Walser
authors.forename: Kostyantyn
authors.initials: K
authors.lastname: Krysan
authors.forename: Sherven
authors.initials: S
authors.lastname: Sharma
authors.forename: Steven M
authors.initials: SM
authors.lastname: Dubinett
authors.forename: Jay M
authors.initials: JM
authors.lastname: Lee
mesh_terms: D042501:Angiogenic Proteins / Q000096:biosynthesis*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002465:Cell Movement / Q000502:physiology; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D006801:Humans; D064094:Interleukin-27 / Q000378:metabolism / Q000494:pharmacology*; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection
chemical_list: D042501:Angiogenic Proteins; D064094:Interleukin-27; D034741:RNA, Small Interfering; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human