title: Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) promotes glioma cell invasion through induction of NF-κB-inducing kinase (NIK) and noncanonical NF-κB signaling.
abstract: BACKGROUND
  High-grade gliomas are one of the most invasive and therapy-resistant cancers. We have recently shown that noncanonical NF-κB/RelB signaling is a potent driver of tumorigenesis and invasion in the aggressive, mesenchymal subtype of glioma. However, the relevant signals that induce activation of noncanonical NF-κB signaling in glioma and its function relative to the canonical NF-κB pathway remain elusive.
  
  
  METHODS
  The ability of tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) to regulate NF-κB signaling and promote tumor progression was investigated in both established and primary high-grade glioma tumor lines using a three-dimensional (3-D) collagen invasion assay. The roles of specific NF-κB proteins in regulating glioma cell invasion and expression of Matrix Metalloproteinase 9 (MMP9) in response to TWEAK were evaluated using shRNA-mediated loss-of-function studies. The ability of NF-κB-inducing kinase (NIK) to promote glioma growth in vivo was investigated using an orthotopic xenograft mouse model.
  
  
  RESULTS
  In glioma cells that display elevated noncanonical NF-κB signaling, loss of RelB attenuates invasion without affecting RelA expression or phosphorylation and RelB is sufficient to promote invasion in the absence of RelA. The cytokine TWEAK preferentially activates the noncanonical NF-κB pathway through induction of p100 processing to p52 and nuclear accumulation of both RelB and p52 without activating the canonical NF-κB pathway. Moreover, TWEAK, but not TNFα, significantly increases NIK mRNA levels. TWEAK also promotes noncanonical NFκB-dependent MMP9 expression and glioma cell invasion. Finally, expression of NIK is sufficient to increase gliomagenesis in vivo.
  
  
  CONCLUSIONS
  Our data establish a key role for NIK and noncanonical NF-κB in mediating TWEAK-induced, MMP-dependent glioma cell invasion. The findings also demonstrate that TWEAK induces noncanonical NF-κB signaling and signal-specific regulation of NIK mRNA expression. Together, these studies reveal the important role of noncanonical NF-κB signaling in regulating glioma invasiveness and highlight the therapeutic potential of targeting activation of NIK in this deadly disease.
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA. cherry@medicine.tamhsc.edu.|Medical Science Graduate 588 Program, Texas A&M University College of Medicine, College Station, TX, USA. cherry@medicine.tamhsc.edu.
authors.forename: Evan M
authors.initials: EM
authors.lastname: Cherry
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA. dwl@medicine.tamhsc.edu.
authors.forename: Dong W
authors.initials: DW
authors.lastname: Lee
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA. jjung@medicine.tamhsc.edu.|Medical Science Graduate 588 Program, Texas A&M University College of Medicine, College Station, TX, USA. jjung@medicine.tamhsc.edu.
authors.forename: Ji-Ung
authors.initials: JU
authors.lastname: Jung
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA. sitcheran@medicine.tamhsc.edu.|The Texas Brain and Spine Institute, Bryan, TX, USA. sitcheran@medicine.tamhsc.edu.
authors.forename: Raquel
authors.initials: R
authors.lastname: Sitcheran
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D000074049:Cytokine TWEAK; D005910:Glioma / Q000235:genetics* / Q000473:pathology*; D057809:HEK293 Cells; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000235:genetics*; D009361:Neoplasm Invasiveness / Q000235:genetics* / Q000473:pathology; D010766:Phosphorylation / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D048069:Tumor Necrosis Factors / Q000235:genetics*; D000097782:NF-kappaB-Inducing Kinase
chemical_list: D000074049:Cytokine TWEAK; D020780:Matrix Metalloproteinase 9; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D048069:Tumor Necrosis Factors; D000097782:NF-kappaB-Inducing Kinase; C109743:TNFSF12 protein, human; C579270:MMP9 protein, human