Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple myeloma (MM) is a currently incurable disease caused by the proliferation of malignant plasma cells. Although the pathogenesis of the disease still remains unclear, recent research in the biology of MM has produced new insights into the factors that control the growth and survival of myeloma cells. Among the growth factors, interleukin-6 (IL-6) has an essential role. Evidence suggests that IL-6 is not only a growth factor, but also a survival factor in MM, inhibiting apoptosis in myeloma cells. IL-6 interacts with several factors which are involved in the pathogenesis of MM, such as adhesion molecules, tumour suppressor genes and oncogenes. Considering the essential role of IL-6, it could serve as a target for new therapeutic interventions. Neutralizing the effect of IL-6 may result in a regression of tumour progression.
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PMID:Role of INTERLEUKIN-6 in the pathogenesis of multiple myeloma. 1081 21

The tumour suppressor activity of p53 in vivo can be subject to pressure from the physiological stress of hypoxia and we report on the development of a cell system to define the p53-dependent stages in the adaptation of cells to hypoxia. p53(+/+) cells exposed to hypoxia exhibited a transient arrest in G2/M, but escaped from this checkpoint and entered a long-term G(0)/G(1) arrest. By contrast, isogenic p53-null cells exposed to hypoxic conditions exhibited a 6-10-fold higher level of apoptosis, suggesting that p53 acts as a survival factor under limiting oxygen concentrations. Surprisingly, hypoxia-dependent growth arrest in p53(+/+) cells did not result in either p21(WAF1) or HIF-1 protein stabilization, but rather promoted a significant decrease in Ser(392)-site phosphorylation at the CK2/FACT site. However, chemically induced anoxia induced Ser(392)-site phosphorylation as well as stabilization of both p53 and HIF-1 proteins. In contrast to hypoxia, 5-flourouracil (5-FU)-induced p53-dependent cell death correlated with enhanced Ser(392) phosphorylation of p53 and elevated p21(WAF1) protein levels. Hypoxia inhibited 5-FU-induced p53-dependent cell death and attenuated p53 phosphorylation at the ATM and CK2/FACT phosphorylation sites. Although anoxia activates the p53 response, hypoxia silences the p53 transactivation pathway and identifies a physiological signalling model to study mechanisms of p53 inactivation under hypoxic conditions.
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PMID:Hypoxia attenuates the p53 response to cellular damage. 1277 95

Netrins are secreted proteins that play a crucial role in neuronal migration and in axon guidance during the development of the nervous system. Netrin-1 has been shown to interact with the transmembrane receptors DCC and UNC5H and these receptors appeared of key importance in mediating the chemotropic activity of netrin-1. Before the discovery of DCC as a netrin-1 receptor, the gene encoding DCC was proposed as a putative tumor suppressor gene because one DCC allele was deleted in roughly 70% of colorectal cancers and its expression was often reduced or absent in colorectal cancer tissues. A putative explanation for such dual roles has recently emerged with the observation that DCC belongs to the growing family of dependence receptors. Such receptors share the property of inducing apoptosis in the absence of ligand, hence creating a cellular state of dependence on the ligand. The other netrin-1 receptors UNC5H were also subsequently proposed to be dependence receptors, suggesting that netrin-1 may not only be a chemotropic factor for neurons but also a survival factor. We describe here netrin-1 and its receptors, together with the molecular signaling pathways initiated upon netrin-1 binding or upon netrin-1 withdrawal leading respectively to axonal/neuronal guidance or cell death induction. We then conclude to the possible roles of DCC and UNC5H pro-apoptotic activities in both nervous system development and tumorigenesis.
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PMID:The dependence receptors DCC and UNC5H as a link between neuronal guidance and survival. 1459 60

Netrin-1 is a chemotropic factor that plays an important role as a survival factor in the adult nervous system. To investigate whether netrin-1 is involved in autoimmune injury of the peripheral nervous system (PNS), the temporal expression of netrin-1 protein was analyzed in the sciatic nerves of Lewis rats with experimental autoimmune neuritis (EAN). Western blot analysis revealed a significant increase in the level of netrin-1 protein in the sciatic nerves of rats on days 11 to 24 post-immunization (p.i.) compared to controls; netrin-1 expression declined by day 30 p.i. Immunohistochemistry revealed that netrin-1 protein was expressed weakly in Schwann cells and vessels in the sciatic nerves of normal and CFA-immunized control rats. In the sciatic nerves of EAN-affected rats, netrin-1 immunoreactivity was increased mainly in the cell membrane and extracellular matrix of OX42-positive macrophages and S100-positive Schwann cells at the peak and recovery phases of EAN. Moreover, the putative netrin-1 receptor, deleted in colorectal cancer (DCC), was expressed mainly in axons, some macrophages, and Schwann cells in EAN-affected sciatic nerves, although the level of protein expression did not change significantly over the course of EAN. We suggest that a significant increase in netrin-1 expression contributes to host cell survival and axon regeneration to counter autoimmune injury and inflammation, which may play a role in recovery from EAN-induced paralysis.
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PMID:Enhanced expression of netrin-1 protein in the sciatic nerves of Lewis rats with experimental autoimmune neuritis: possible role of the netrin-1/DCC binding pathway in an autoimmune PNS disorder. 1633 79

The intersection between regulatory pathways responsive to metabolic fluctuation on one hand, and to cellular stress on the other, is a fascinating area within which NAD/NADH responsive proteins play a major role [1, 2]. A key player amongst these is SIRT1, a member of the mammalian sirtuin family (SIRT1-7). SIRT1 is an NAD-dependent deacetylase with critical functions in the maintenance of homeostasis and cell survival. In this review I shall focus upon (i) the cellular regulation of SIRT1 expression and (ii) the cellular regulation of SIRT1 activity. In addition the distinction between basal and stress-induced functions will be addressed: do they simply reflect a sliding scale of response, or are they mechanistically distinct? Elevated levels of SIRT1 are evident in cancer and SIRT1 can function as a cancer-specific survival factor in human cell lines. However, in a mouse model SIRT1 is reported to function as a tumour suppressor. Possible explanations for this apparent discrepancy will be considered. Given the high profile of SIRT1 as a potential therapeutic target it is clearly important to clarify its basal functioning in relation to differentiation, cell type, intercellular communication, and to age-related disease states including neurodegeneration and cancer.
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PMID:Cellular regulation of SIRT1. 1914 1

Tensins are large intracellular proteins believed to link the extracellular matrix to the cytoskeleton via integrins. Tensins are multidomain proteins consisting of homologous C1, PTPase, C2, SH2 and PTB domains. Full-length Tensin proteins can undergo cleavage inside cells, thus yielding domains in isolation that may have discrete subcellular localisations and downstream effects. We expressed different isoforms of Tensin2 and their individual domains as recombinant green fluorescent protein (GFP)-fusion constructs in DU145 human prostate cancer cells. Under fluorescence confocal microscopy, the isolated domains of Tensin2 all displayed discrete distributions throughout the cytoplasm and the nucleus. In particular, partial constructs containing the C1 domain localised preferentially to the nucleus, including the isolated C1 domain and the PTPase domain. In contrast, all three full-length isoforms of Tensin2 were present exclusively in discrete punctate bodies throughout the cytoplasm. This punctate staining showed colocalisation with the tumour suppressor protein DLC-1 as well as with actin (phalloidin). Furthermore, DU145 cells transiently expressing partial Tensin2 constructs containing the PTB domain showed an increased haptotactic migration. In addition, stimulation of renal carcinoma cells stably expressing Tensin2 by the survival factor Gas6 caused phosphorylation of its receptor Axl, but no effect on Tensin2, which was already maximally phosphorylated at time 0. In conclusion, our results indicate that differential proteolytic cleavage of Tensin2 can liberate domains with discrete localisations and functions, which has implications for the role of Tensins in cancer cell survival and motility.
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PMID:Individual domains of Tensin2 exhibit distinct subcellular localisations and migratory effects. 1974 64