A novel role of tissue factor pathway inhibitor-2 in apoptosis of malignant human gliomas.
Tissue factor pathway inhibitor-2 (TFPI-2) is a 32 kDa serine protease inhibitor found at high levels in extracellular matrix. Recombinant human TFPI-2 has recently been shown to be a strong inhibitor of trypsin, plasmin, plasma kallikrein, and factor XIa amidolytic activity. Earlier studies in our laboratory showed that the expression of TFPI-2 is lost during tumor progression in human gliomas. We stably transfected this protease inhibitor in multiform glioblastoma cell line (SNB-19) and in low-grade glioma cell line (Hs683) in sense and antisense orientation respectively. This confirmed that the upregulation/down-regulation of TFPI-2 plays a significant role in the invasive behavior of human gliomas both in vitro and in vivo models. Collectively, these results suggested an idea to determine whether TFPI-2 is necessary for cell survival and inhibition of tumor formation in nude mice, due to apoptosis of intracerebrally injected SNB-19 cells. In the present study we determined p-ERK levels and found that they are decreased in TFPI-2 over-expressed clones (SNB-19) and increased in TFPI-2 down-regulated clones (Hs683). We also checked the levels of BAX/BCl-2, caspases (for e.g., 9, 7, 3, 8), PARP, cytochrome-c and Apaf-1. Moreover, the increase of apoptosis in vitro is associated with increased and decreased expression of apoptotic protein BAX in sense clones (SNB-19) and antisense clones (Hs683) respectively, when compared to controls and vice versa with Bcl-2 the anti-apoptotic protein. Caspases (9, 7 and 3), cytochrome-c, Apaf-1 and PARP levels are increased in SNB-19 and decreased in Hs683. Caspase 8 was not expressed in either cell line. Caspases 9 and 3 activity assay revealed higher activity in sense clones (SNB-19) but lesser in antisense clones (Hs683) compared to controls. This is the first report of TFPI-2 playing a novel role in cell survival in human gliomas.
Tasiou
A
A
Department of Biomedical and Therapeutic Sciences, Division of Cancer Biology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL 61656, USA.
Konduri
S D
SD
Yanamandra
N
N
Dinh
D H
DH
Olivero
W C
WC
Gujrati
M
M
Obeyesekere
M
M
Rao
J S
JS
D017209:Apoptosis; D053477:Apoptotic Protease-Activating Factor 1; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D015536:Down-Regulation; D015942:Factor VIIa / Q000037:antagonists & inhibitors; D005822:Genetic Vectors; D005910:Glioma / Q000378:metabolism / Q000473:pathology*; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000473:pathology*; D051028:bcl-2-Associated X Protein
C506592:APAF1 protein, human; D053477:Apoptotic Protease-Activating Factor 1; C494826:BAX protein, human; D003574:Cytochrome c Group; D006023:Glycoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D015842:Serine Proteinase Inhibitors; D051028:bcl-2-Associated X Protein; C021240:tissue-factor-pathway inhibitor 2; D020928:Mitogen-Activated Protein Kinases; D015942:Factor VIIa; D020169:Caspases