title: Suppression of MMP-2 attenuates TNF-α induced NF-κB activation and leads to JNK mediated cell death in glioma.
abstract: BACKGROUND
  Abrogation of apoptosis for prolonged cell survival is essential in cancer progression. In our previous studies, we showed the MMP-2 downregulation induced apoptosis in cancer cell lines. Here, we attempt to investigate the exact molecular mechanism of how MMP-2 depletion leads to apoptosis in glioma xenograft cell lines.
  
  
  RESULTS
  MMP-2 transcriptional suppression by MMP-2siRNA (pM) induces apoptosis associated with PARP, caspase-8 and -3 cleavage in human glioma xenograft cells 4910 and 5310. Western blotting and cytokine array showed significant decrease in the cellular and secreted levels of TNF-α with concomitant reduction in TNFR1, TRADD, TRAF2, RIP, IKKβ and pIκBα expression levels resulting in inhibition of p65 phosphorylation and nuclear translocation in pM-treated cells when compared to mock and pSV controls. In addition MMP-2 suppression led to elevated Fas-L, Fas and FADD expression levels along with increased p38 and JNK phosphorylation. The JNK-activity assay showed prolonged JNK activation in pM-transfected cells. Specific inhibition of p38 with SB203580 did not show any effect whereas inhibition of JNK phosphorylation with SP600125 notably reversed pM-induced cleavage of PARP, caspase-8 and -3, demonstrating a significant role of JNK in pM-induced cell death. Supplementation of rhMMP-2 counteracted the effect of pM by remarkably elevating TNF-α, TRADD, IKKβ and pIκBα expression and decreasing FADD, Fas-L, and phospho-JNK levels. The EMSA analysis indicated significant reversal of pM-inhibited NF-κB activity by rhMMP-2 treatment which rescued cells from pM-induced cell death. In vivo studies indicated that pM treatment diminished intracranial tumor growth and the immuno histochemical analysis showed decreased phospho-p65 and enhanced phospho-JNK levels that correlated with increased TUNEL-positive apoptotic cells in pM-treated tumor sections.
  
  
  CONCLUSIONS
  In summary, our study implies a role of MMP-2 in the regulation of TNF-α mediated constitutive NF-κB activation and Fas-mediated JNK mediated apoptosis in glioma xenograft cells in vitro and in vivo.
authors.affiliation: Departments of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America.
authors.forename: Divya
authors.initials: D
authors.lastname: Kesanakurti
authors.forename: Chandramu
authors.initials: C
authors.lastname: Chetty
authors.forename: Praveen
authors.initials: P
authors.lastname: Bhoopathi
authors.forename: Sajani S
authors.initials: SS
authors.lastname: Lakka
authors.forename: Bharathi
authors.initials: B
authors.lastname: Gorantla
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tsung
authors.forename: Jasti S
authors.initials: JS
authors.lastname: Rao
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D005910:Glioma / Q000235:genetics / Q000378:metabolism* / Q000628:therapy*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000873:Anthracenes; D004791:Enzyme Inhibitors; D007093:Imidazoles; D016328:NF-kappa B; D011725:Pyridines; D034741:RNA, Small Interfering; D019717:Tissue Inhibitor of Metalloproteinase-3; D014409:Tumor Necrosis Factor-alpha; C432165:pyrazolanthrone; D048031:JNK Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; C093642:SB 203580