Non-steroidal anti-inflammatory drug (NSAID), sulindac has chemopreventive and anti-tumorigenic properties, however, the molecular mechanism of this inhibitory action has not been clearly defined. The Akt/protein kinase B, serine/threonine kinase is well known as an important mediator of many cell survival signaling pathways. In the present study, we demonstrate that down-regulation of Akt is a major effect of anti-invasiveness property of sulindac and its metabolites in glioblastoma cells. Myristoylated Akt (MyrAkt) transfected U87MG glioblastoma cells showed increase invasiveness, whereas DN-Akt transfected cells showed decrease invasiveness indicating that Akt potently promoted glioblastoma cell invasion. MMP-2 promoter and enzyme activity were up-regulated in Akt kinase activity dependent manner. Sulindac and its metabolites down-regulated Akt phosphorylation, inhibited MMP-2 production, and significantly inhibited invasiveness of human glioblastoma cells. In addition, sulindac and LY294002, a selective inhibitor of phosphoinositide 3-kinase (PI3K), synergistically inhibited the invasion of glioblastoma cells. Furthermore, only celecoxib showed Akt phosphorylation reduction and an anti-invasivness in glioblastoma cells, whereas aspirin, ketoprofen, ketorolac, and naproxen did not. In conclusion, our results provide evidence that down-regulation of Akt pathway and MMP-2 may be one of the mechanisms by which sulindac and its metabolites inhibit glioblastoma cell invasion.

In order to define the role of As2O3 in regulating the tumor cell invasiveness, the effects of As2O3 on secretion of matrix metalloproteinases (MMPs) and urokinase plasminogen activator (uPA), and in vitro invasion of HT1080 human fibrosarcoma cells were examined. As2O3 inhibited cell adhesion to the collagen matrix in a concentration dependent manner, whereas the same treatment enhanced cell to cell interaction. In addition, As2O3 inhibited migration and invasion of HT1080 cells stimulated with phorbol 12-myristate 13-aceate (PMA), and suppressed the expression of MMP-2, -9, membrane type-1 MMP, uPA, and uPA receptor (uPAR). In contrast, As2O3 increased the expression of tissue inhibitor of metalloproteinase (TIMP)-1 and PA inhibitor (PAI)-1, and reduced the MMP-2, -9, and uPA promoter activity in the presence and absence of PMA. Furthermore, the promoter stimulating and DNA binding activity of nuclear factor-kappaB (NF-kappaB) was blocked by As2O3, whereas the activator protein-1 activity was unchanged. Pretreatment of the cells with N-acetyl-L-cysteine (NAC) significantly prevented suppression of MMPs and uPA secretion, DNA binding activity of NF-kappaB, and in vitro invasion of HT1080 cells by As2O3, suggesting a role of reactive oxygen species (ROS) in this process. These results suggest that As2O3 inhibits tumor cell invasion by modulating the MMPs/TIMPs and uPA/uPAR/PAI systems of extracellular matrix (ECM) degradation. In addition, the generation of ROS and subsequent suppression of NF-kappaB activity by As2O3 might partly be responsible for the phenomena. Overall, As2O3 shows potent activity controlling tumor cell invasiveness in vitro.