| Autor: |
Hsu LJ; Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, PA, USA.; Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Hong Q; Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, PA, USA., Chen ST; Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, PA, USA.; Department of Cell Biology and Anatomy, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Kuo HL; Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Schultz L; Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, PA, USA., Heath J; Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, PA, USA., Lin SR; Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Lee MH; Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Li DZ; Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Li ZL; Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Cheng HC; Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC., Armand G; Glycomed Research Inc., Hastings on Hudson, New York, NY, USA., Chang NS; Guthrie Research Institute, Laboratory of Molecular Immunology, Sayre, PA, USA.; Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, ROC.; Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan, ROC.; Graduate Institute of Biomedical Sciences, College of Medicine, China Medical University, Taichung, Taiwan, ROC. |
| Abstrakt: |
Malignant cancer cells frequently secrete significant amounts of transforming growth factor beta (TGF-β), hyaluronan (HA) and hyaluronidases to facilitate metastasizing to target organs. In a non-canonical signaling, TGF-β binds membrane hyaluronidase Hyal-2 for recruiting tumor suppressors WWOX and Smad4, and the resulting Hyal-2/WWOX/Smad4 complex is accumulated in the nucleus to enhance SMAD-promoter dependent transcriptional activity. Yeast two-hybrid analysis showed that WWOX acts as a bridge to bind both Hyal-2 and Smad4. When WWOX-expressing cells were stimulated with high molecular weight HA, an increased formation of endogenous Hyal-2/WWOX/Smad4 complex occurred rapidly, followed by relocating to the nuclei in 20-40 min. In WWOX-deficient cells, HA failed to induce Smad2/3/4 relocation to the nucleus. To prove the signaling event, we designed a real time tri-molecular FRET analysis and revealed that HA induces the signaling pathway from ectopic Smad4 to WWOX and finally to p53, as well as from Smad4 to Hyal-2 and then to WWOX. An increased binding of the Smad4/Hyal-2/WWOX complex occurs with time in the nucleus that leads to bubbling cell death. In contrast, HA increases the binding of Smad4/WWOX/p53, which causes membrane blebbing but without cell death. In traumatic brain injury-induced neuronal death, the Hyal-2/WWOX complex was accumulated in the apoptotic nuclei of neurons in the rat brains in 24 hr post injury, as determined by immunoelectron microscopy. Together, HA activates the Hyal-2/WWOX/Smad4 signaling and causes bubbling cell death when the signaling complex is overexpressed. |
