Tissue transglutaminase is not increased during apoptosis of HT-1080 human fibrosarcoma cells

• Published in: Experimental and toxicologic pathology : official journal of the Gesellschaft für Toxikologische Pathologie 1998-03, Vol.50 (1), p.79-82
• Main Authors: Lim, S.D., Bae, S.I., Kim, I.G., Park, S.C., Chung, S.I., Nomizu, M., Kleinman, H.K., Kim, W.H.
• Format: Article
• Language: English
• Subjects: Ageing, cell death; Apoptosis; Apoptosis - physiology; Biological and medical sciences; Cell Adhesion; Cell physiology; Dose-Response Relationship, Drug; extracellular; Extracellular matrix; Fibrosarcoma - enzymology; Fibrosarcoma cells, HT-1080; Fundamental and applied biological sciences. Psychology; Humans; In Vitro Techniques; Laminin; Matrix; Molecular and cellular biology; Peptide Fragments - pharmacology; Transglutaminase; Transglutaminases - metabolism; Tumor Cells, Cultured
• ISSN: 0940-2993; 1618-1433
• DOI: 10.1016/S0940-2993(98)80076-6

Tissue transglutaminase (tTGase), a cytosolic enzyme which catalyzes the covalent cross-linking of proteins, is thought to be involved in the apoptosis. Here, we tested whether tTGase is involved during HT-1080 fibrosarcoma cell apoptosis induced by the YIGSR (Tyr-Ile-Gly-Ser-Arg) peptide. This sequence is derived from the laminin α1 chain, and its potency is increased by the formation of a 16mer polymerization using a lysine tree structure. Cells were treated with several different concentrations of Ac-Y16 for 16 hours, and apoptosis was increased in dose-dependent manner. When assayed by incorporation of [ 14C] putrescine into succinylated casein, total transglutaminase activity was decreased in parallel with the change in the number of attached cells. Western blot analysis using polyclonal antibody against tTGase showed that the tTGase protein level had not been significantly changed when equal amounts of the protein were applied. To confirm this result, we induced apoptosis of these cells by coating the tissue culture plates with non-adhesive poly-hydroxyethyl methacrylate (HEMA). Western blot analysis showed that the tTGase protein level did not change during this process of apoptosis. Although it has been suggested that tTGase is involved in the process of apoptosis of various cells in vitro and in vivo, our data demonstrate that tTGase is not involved in the process of apoptosis of HT-1080 human fibrosarcoma cell induced by either Ac-Y16 or a non-adhesive culture surface.