Conformational changes and translocation of tissue-transglutaminase to the plasma membranes: role in cancer cell migration

Abstract

BackgroundTissue-transglutaminase (TG2), a dual function G-protein, plays key roles in cell differentiation and migration. In our previous studies we reported the mechanism of TG2-induced cell differentiation. In present study, we explored the mechanism of how TG2 may be involved in cell migration.MethodsTo study the mechanism of TG2-mediated cell migration, we used neuroblastoma cells (SH-SY5Y) which do not express TG2, neuroblastoma cells expressing exogenous TG2 (SHYTG2), and pancreatic cancer cells which express high levels of endogenous TG2. Resveratrol, a natural compound previously shown to inhibit neuroblastoma and pancreatic cancer in the animal models, was utilized to investigate the role of TG2 in cancer cell migration. Immunofluorescence assays were employed to detect expression and intracellular localization of TG2, and calcium levels in the migrating cells. Native gel electrophoresis was performed to analyze resveratrol-induced cellular distribution and conformational states of TG2 in migrating cells. Data are presented as the mean and standard deviation of at least 3 independent experiments. Comparisons were made among groups using one-way ANOVA followed by Tukey-Kramer ad hoc test.ResultsTG2 containing cells (SHYTG2 and pancreatic cancer cells) exhibit increased cell migration and invasion in collagen-coated and matrigel-coated transwell plate assays, respectively. Resveratrol (1 μM-10 μM) prevented migration of TG2-expressing cells. During the course of migration, resveratrol increased the immunoreactivity of TG2 without affecting the total TG2 protein level in migrating cells. In these cells, resveratrol increased calcium levels, and depletion of intracellular calcium by a calcium chelator, BAPTA, attenuated resveratrol-enhanced TG2 immunoreactivity. In native-polyacrylamide gels, we detected an additional TG2 protein band with slower migration in total cell lysates of resveratrol treated cells. This TG2 form is non-phosphorylated, exclusively present in plasma membrane fractions and sensitive to intracellular Ca2+ concentration suggesting a calcium requirement in TG2-regulated cell migration.ConclusionsTaken together, we conclude that resveratrol induces conformational changes in TG2, and that Ca2+-mediated TG2 association with the plasma membrane is responsible for the inhibitory effects of resveratrol on cell migration.

CD49f Acts as an Inflammation Sensor to Regulate Differentiation, Adhesion, and Migration of Human Mesenchymal Stem Cells

“…TG2 is ubiquitously expressed and is predominantly localized to the cytosol, nucleus, and the cell membrane compartments, and distinct interactions with other proteins in the local microenvironment jointly regulate specific physiological functions . A recent published report showed that the association of TG2 with the plasma membrane was responsible for the inhibitory effects of resveratrol on the migration of human neuroblastoma cells and pancreatic cell lines . For its ability to mediate the adhesion of monocytic cells to the ECM by forming complex with beta‐integrin (β1, −3, and −5), TG2 was also suggested to be involved in the extravasation and migration of monocytes during inflammation .…”

Corneal Stiffness and Collagen Cross-Linking Proteins in Glaucoma: Potential for Novel Therapeutic Strategy

“…TG2 has also been implicated in cancer, where it is associated with cancer cell migration and invasion. 90 In contrast to LOX and TG2, AGEs elicit synergism with oxidative stress. AGEs lead to the generation of reactive oxygen species (ROS) and AGE production is promoted by oxidative stress.…”

Transglutaminase is a tumor cell and cancer stem cell survival factor

“…Likewise, treatment of AsPC‐1 pancreatic cancer cells with high temperature results in apoptotic cell death associated with enhanced TG2‐dependent protein crosslinking . Treatment of pancreatic cancer cells with 1–10 μM resveratrol, a diet‐derived cancer prevention agent, is associated with accumulation of a slower mobility (open, crosslinking) form of TG2 which leads to reduced cell survival . Thus, folded/closed (signaling) TG2 is associated with enhanced cancer cell survival, while open/extended (crosslinking) TG2 is associated with cell death.…”