Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51812 (mitogen-activated protein)
 10,636 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin K2 (VK2) has been shown to have a potent anti-tumor effect against several cancer types including hepatocellular carcinoma (HCC), but the mechanisms remain to be elucidated. Matrix metalloproteinase (MMP) plays an important role in the invasion and metastasis of cancer cells, but it is not known whether VK2 regulates the expression of MMPs. Human HCC cell lines were treated with VK2 combined with 12-O-tetradecanoyl phorbol-13 acetate (TPA) and the expression of MMPs was examined by reporter gene assay, RT-PCR and Western blotting. VK2 inhibited the basal and TPA-induced expression of MMP-1, -3 and -7 at the transcriptional, mRNA and protein levels in a dose-dependent manner. VK2 also inhibited the TPA-induced activation of NF-kappaB and AP-1 activity. The inhibitors against NF-kappaB and mitogen-activated protein kinases (MAP kinase) including ERK and JNK pathways suppressed TPA-induced luciferase activity of MMP-1, -3 and -7 promoters. These data suggest that VK2 inhibits MMP expression by suppressing NF-kappaB and MAP kinase activity and might be potentially useful in the treatment of HCC.
 ...
PMID:Inhibition of matrix metalloproteinase expression by menatetrenone, a vitamin K2 analogue. 1963 10

Apoptosis is a mechanism that regulates hepatic tissue homeostasis and contributes to both acute and chronic injury in liver disease. The apoptotic signaling cascade involves activation of the death-inducing signaling complex (DISC) and subsequent recruitment of proteins containing death effector domains (DED), which regulate downstream effector molecules. Prominent among these are the Fas-associated death domain (FADD) and the cellular caspase 8-like inhibitory protein (cFLIP), and alterations in these proteins can lead to severe disruption of physiological processes, including acute liver failure or hepatocellular carcinoma. Their role in cell signaling events independent of the DISC remains undetermined. Oxidative stress can cause cell injury from direct effects on molecules or by activating intracellular signaling pathways including the mitogen-activated protein kinases (MAPKs). In this context, prolonged activation of the cJun N-terminal kinase (JNK)/AP-1/cJun signaling pathway promotes hepatocellular apoptosis, whereas activation of the extracellular signal-regulated kinase (Erk) exerts protection. We investigated the roles of FADD and cFLIP in acute oxidant stress induced by the superoxide generator menadione in hepatocytes. Menadione resulted in dose-dependent predominantly necrotic cell death. Hepatocytes expressing a truncated, dominant-negative FADD protein were partially protected, whereas cFLIP-deficient hepatocytes displayed increased cell death from menadione. In parallel, Erk phosphorylation was enhanced in hepatocytes expressing dnFADD and decreased in cFLIP-deficient hepatocytes. Hepatocyte injury was accompanied by increased release of proapoptotic factors and increased JNK/cJun activation. Thus, FADD and cFLIP contribute to the regulation of cell death from acute oxidant stress in hepatocytes involving MAPK signaling. This implies that DED-containing proteins are involved in the regulation of cellular survival beyond their role in cell death receptor-ligand-mediated apoptosis.
 ...
PMID:The role of death effector domain-containing proteins in acute oxidative cell injury in hepatocytes. 2240 16

Gap junction-mediated cell-cell interactions are highly conserved and play essential roles in cell survival, proliferation, differentiation and patterning. We report that Connexin 32 (Cx32)-mediated gap junctional intercellular communication (GJIC) is necessary for human embryonic stem cell-derived hepatocytes (hESC-Heps) during step-wise hepatic lineage restriction and maturation. Vitamin K2, previously shown to promote Cx32 expression in mature hepatocytes, up-regulated Cx32 expression and GJIC activation during hepatic differentiation and maturation, resulting in significant increases of hepatic markers expression and hepatocyte functions. In contrast, negative Cx32 regulator 2-aminoethoxydiphenyl borate blocked hESC-to-hepatocyte maturation and muted hepatocyte functions through disruption of GJIC activities. Dynamic gap junction organization and internalization are phosphorylation-dependent and the p38 mitogen-activated protein kinases pathway (MAPK) can negatively regulate Cxs through phosphorylation-dependent degradation of Cxs. We found that p38 MAPK inhibitor SB203580 improved maturation of hESC-Heps correlating with up-regulation of Cx32; by contrast, the p38 MAPK activator, anisomycin, blocked hESC-Heps maturation correlating with down-regulation of Cx32. These results suggested that Cx32 is essential for cell-cell interactions that facilitate driving hESCs through hepatic-lineage maturation. Regulators of both Cx32 and other members of its pathways maybe used as a promising approach on regulating hepatic lineage restriction of pluripotent stem cells and optimizing their functional maturation.
 ...
PMID:Connexin 32-mediated cell-cell communication is essential for hepatic differentiation from human embryonic stem cells. 3224 99