Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor growth and metastasis are multifaceted processes that mainly involve cell adhesion, proteolytic degradation of the extracellular matrix, and cell migration. Syk is a member of a tyrosine kinase family that is expressed mostly in hematopoietic cells. Syk is expressed in cell lines of epithelial origin, but its function in these cells remains unknown. Here we report that Syk is expressed in MCF-7 cells but not in MDA-MB-231 cells. The overexpression of wild type Syk kinase but not kinase-negative Syk suppressed cell motility and inhibited the activation of phosphatidylinositol (PI) 3'-kinase in MDA-MB-231 cells. In contrast, when Syk-specific antisense S-oligonucleotide but not the sense S-oligonucleotide was transfected to MCF-7 cells the level of PI 3'-kinase activity as well as cell motility were increased. The MDA-MB-231 cells transfected with wild type Syk cDNA followed by treatment with piceatannol, a Syk inhibitor, enhanced cell motility and PI 3'-kinase activity. Pervanadate, a phosphotyrosine phosphatase inhibitor, induced PI 3'-kinase activity and stimulated the interaction between the inhibitor of nuclear factor kappa B alpha (I kappa B alpha) and the p85 alpha domain of PI 3'-kinase through tyrosine phosphorylation of the I kappa B alpha, which ultimately resulted in nuclear factor kappa B (NF kappa B) activation. Pervanadate had no effect on the activation of Syk in these cells. However, Syk suppressed the NF kappa B transcriptional activation and interaction between I kappa B alpha and PI 3'-kinase by inhibiting the tyrosine phosphorylation of I kappa B alpha. Syk, PI 3'-kinase inhibitors, and NF kappa B inhibitory peptide inhibited urokinase type plasminogen activator (uPA) secretion and cell motility in these cells. To our knowledge, this is the first report that Syk suppresses the cell motility and inhibits the PI 3'-kinase activity and uPA secretion by blocking NF kappa B activity through tyrosine phosphorylation of I kappa B alpha. These data further demonstrate a functional molecular link between Syk-regulated PI 3'-kinase activity and NF kappa B-mediated uPA secretion, and all of these ultimately control the motility of breast cancer cells.
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PMID:Syk, a protein-tyrosine kinase, suppresses the cell motility and nuclear factor kappa B-mediated secretion of urokinase type plasminogen activator by inhibiting the phosphatidylinositol 3'-kinase activity in breast cancer cells. 1247 28

We have recently reported that osteopontin (OPN) induces nuclear factor kappaB (NFkappaB)-mediated promatrix metalloproteinase-2 activation through IkappaBalpha/IKK signaling pathways and that curcumin (diferulolylmethane) down-regulates these pathways (Philip, S., and Kundu, G. C. (2003) J. Biol. Chem. 278, 14487-14497). However, the molecular mechanism by which upstream kinases regulate the OPN-induced NFkappaB activation and urokinase type plasminogen activator (uPA) secretion in human breast cancer cells is not well defined. Here we report that OPN induces the phosphatidylinositol 3'-kinase (PI 3'-kinase) activity and phosphorylation of Akt in highly invasive MDA-MB-231 and low invasive MCF-7 cells. The OPN-induced Akt phosphorylation was inhibited when cells were transfected with a dominant negative mutant of the p85 domain of PI 3-kinase (Deltap85) and enhanced when cells were transfected with an activated form of PI 3-kinase (p110CAAX), indicating that PI 3'-kinase is involved in Akt phosphorylation. OPN enhances the interaction between IkappaBalpha kinase (IKK) and phosphorylated Akt. OPN also induces NFkappaB activation through phosphorylation and degradation of IkappaBalpha by inducing the IKK activity. However, both pharmacological (wortmannin and LY294002) and genetic (Deltap85) inhibitors of PI 3'-kinase inhibited OPN-induced Akt phosphorylation, IKK activity, and NFkappaB activation through phosphorylation and degradation of IkappaBalpha. OPN also enhances uPA secretion, cell motility, and extracellular matrix invasion. Furthermore, cells transfected with Deltap85 or the super-repressor form of IkappaBalpha suppressed the OPN-induced uPA secretion and cell motility, whereas cells transfected with p110CAAX enhanced these effects. Pretreatment of cells with PI 3-kinase inhibitors or NFkappaB inhibitory peptide (SN-50) reduced the OPN-induced uPA secretion, cell motility, and invasion. To our knowledge, this is first report that OPN induces NFkappaB activity and uPA secretion by activating PI 3'-kinase/Akt/IKK-mediated signaling pathways and further demonstrates a functional molecular link between OPN-induced PI 3'-kinase-dependent Akt phosphorylation and NFkappaB-mediated uPA secretion, and all of these ultimately control the motility of breast cancer cells.
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PMID:Osteopontin stimulates cell motility and nuclear factor kappaB-mediated secretion of urokinase type plasminogen activator through phosphatidylinositol 3-kinase/Akt signaling pathways in breast cancer cells. 1277 Nov 44

Cancer progression depends on an accumulation of metastasis supporting cell signaling molecules that target signal transduction pathways and ultimately gene expression. Osteopontin (OPN) is one such chemokine like metastasis gene which plays a key signaling event in regulating the oncogenic potential of various cancers by controlling cell motility, invasiveness and tumor growth. We have reported that OPN stimulates tumor growth and nuclear factor kappaB (NFkappaB)-mediated promatrix metalloproteinase-2 (pro-MMP-2) activation through IkappaBalpha/IKK (IkappaBalpha kinase) signaling pathway in melanoma cells. Urokinase type plasminogen activator (uPA), a widely acting serine protease degrades the ECM components and plays a pivotal role in cancer progression. However, the molecular mechanism by which upstream kinases regulate the OPN-induced NFkappaB activation and uPA secretion in human breast cancer cells is not well defined. Here we report that OPN induces the phosphatidylinositol 3'-kinase (PI 3'-kinase) activity and phosphorylation of Akt/PKB (protein kinase B) in highly invasive (MDA-MB-231) and low invasive (MCF-7) breast cancer cells. The OPN-induced Akt phosphorylation was inhibited when cells were transfected with dominant negative mutant of p85 domain of PI 3'-kinase (Deltap85) indicating that PI 3'-kinase is involved in Akt phosphorylation. OPN enhances the interaction between IkappaBalpha kinase (IKK) and phosphorylated Akt. OPN also induces NFkappaB activation through phosphorylation and degradation of IkappaBalpha by inducing the IKK activity. OPN also enhances uPA secretion, cell motility and ECM-invasion. Furthermore, cells transfected with Deltap85 or super-repressor form of IkappaBalpha suppressed the OPN-induced uPA secretion and cell motility. Pretreatment of cells with PI 3'-kinase inhibitors or NFkappaB inhibitory peptide (SN50) reduced the OPN-induced uPA secretion, cell motility and ECM-invasion. Taken together, OPN induces NFkappaB activity and uPA secretion by activating PI 3'-kinase/Akt/IKK-mediated signaling pathways and further demonstrates a functional molecular link between OPN induced PI 3'-kinase dependent Akt phosphorylation and NFkappaB-mediated uPA secretion, and all of these ultimately control the motility and invasiveness of breast cancer cells.
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PMID:Osteopontin: it's role in regulation of cell motility and nuclear factor kappa B-mediated urokinase type plasminogen activator expression. 1601 53