Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

p14ARF is a tumor suppressor that controls a well-described p53/Mdm2-dependent checkpoint in response to oncogenic signals. Here, new insights into the tumor-suppressive function of p14ARF are provided. We previously showed that p14ARF can induce a p53-independent G2 cell cycle arrest. In this study, we demonstrate that the activation of ATM/ATR/CHK signaling pathways contributes to this G2 checkpoint and highlight the interrelated roles of p14ARF and the Tip60 protein in the initiation of this DNA damage-signaling cascade. We show that Tip60 is a new direct p14ARF binding partner and that its expression is upregulated and required for ATM/CHK2 activation in response to p14ARF. Strikingly, both p14ARF and Tip60 products accumulate following a cell treatment with alkylating agents and are absolutely required for ATM/CHK2 activation in this setting. Moreover, and consistent with p14ARF being a determinant of CHK2 phosphorylation in lung carcinogenesis, a strong correlation between p14ARF and phospho-CHK2 (Thr68) protein expression is observed in human lung tumors (P < 0.00006). Overall, these data point to a novel regulatory pathway that mediates the p53-independent negative-cell-growth control of p14ARF. Inactivation of this pathway is likely to contribute to lung carcinogenesis.
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PMID:p14ARF activates a Tip60-dependent and p53-independent ATM/ATR/CHK pathway in response to genotoxic stress. 1670 83

The aim of this study was to investigate the changes in expression pattern of the most important genes connected with apoptosis in proliferative apoptotic lesions (hyperplasia, adenoma), applying cDNA microarray technique, in order to promote the possible diagnostic or therapeutic utilisation of any difference in gene expression compared to the healthy (normal) parathyroid gland. Samples were taken from surgically removed 2 hyperplasias, 2 adenomas and 2 normal parathyroid glands. The Apoptosis Gene Array (Superarray) was used. This contains 112 genes, in tetraspot arrangement. The probes measured 250-600 base pairs. Streptavidin was bound to the array. CDP Star TM chemiluminescent substrate was used for detection. The samples deriving from hyperplasia or adenoma were compared to samples from normal parathyroid glands. The following genes were overexpressed in both hyperplasia and adenoma: CHEK1, ATM, BCL-XL, FAS, TNF, cIAP1, TRAIL, FADD, CASP 4,5,6,8, CD120b, CD137, LTA, TANK, TARF2, CAD, LIGHTR, DR3LG. CASP1,10, BFAR, BOD, BCL2L2, TRANCE were underexpressed in both hyperplasia and adenoma. Genes overexpressed only in hyperplasia were: MDM2, MCL1, BCL2A1, BLK, RIPK2, CD40LG, TRAF5, HUS1, BNIP3. Underexpressed only in hyperplasia: BOK, CIDEA, TRAF1, TRIP. Overexpressed only in adenoma: APOLLON, RIPK1, LTB, LTBR, CASP2,13, cIAP2, CIDEB. Underexpressed only in adenoma: TRAF4 and FASLG. Overexpresion or underexpression meant 1.5-fold difference from normal average values. As a result of this study, both pro-apoptotic and antiapoptotic genes were identified in hyperplasia and adenoma of the parathyroid gland. It seems that increased proliferation is connected also with increased apoptotic activity, but tumor cell candidates are able to survive, by activation of signal pathways resulting in overexpresion of anti-apoptotic genes.
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PMID:[Changes in gene expression in the course of proliferative processes in the parathyroid gland]. 1688 77

Basic transcription factor 3 (BTF3) acts as a transcription factor and modulator of apoptosis, and is differentially expressed in colorectal cancer and glioblastomas. In the present study, the expression of BTF3, as well as its role in apoptosis and gene transcription, was analyzed in pancreatic ductal adenocarcinoma (PDAC). QRT-PCR, immunohistochemistry, immunoblotting, and immunofluorescence analyses were carried out to investigate BTF3 mRNA/protein expression and localization. BTF3 silencing in pancreatic cancer cells was performed using specific siRNA molecules. Functional analyses were carried out using cell growth assays, apoptosis assays, and DNA array analysis. BTF3 and BTF3a exhibited 1.3-fold and 4.6-fold increased median mRNA levels in PDAC tissues, compared to normal pancreatic tissues. BTF3 localized mainly in the cytoplasm and nuclei of tubular complexes and pancreatic cancer cells. Pancreatic cancer cell lines expressed the mRNA and protein of BTF3a (27 kDa) and BTF3b (22 kDa) isoforms. BTF3 silencing using specific siRNA molecules did not influence apoptosis induced by chemotherapy or radiotherapy. In contrast, BTF3 silencing resulted in down-regulation of several cancer-associated genes, including EPHB2, ABL2, HPSE2 and ATM, and up-regulation of KRAG, RRAS2, NFkappa-B, MRVI1, MADCAM1 and others. In conclusion, BTF3 is overexpressed in PDAC, where it acts as a transcriptional regulator rather than a direct modulator of apoptosis.
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PMID:Basic transcription factor 3 (BTF3) regulates transcription of tumor-associated genes in pancreatic cancer cells. 1731 87

Ultraviolet (UV) radiation is a mutagen of major clinical importance in humans. UV-induced damage activates multiple signaling pathways, which initiate DNA repair, cell cycle arrest and apoptosis. To better understand these pathways, we studied the responses to UV-C light (254 nm) of germ cells in Caenorhabditis elegans. We found that UV activates the same cellular responses in worms as in mammalian cells. Both UV-induced apoptosis and cell cycle arrest were completely dependent on the p53 homolog CEP-1, the checkpoint proteins HUS-1 and CLK-2, and the checkpoint kinases CHK-2 and ATL-1 (the C. elegans homolog of ataxia telangiectasia and Rad3-related); ATM-1 (ataxia telangiectasia mutated-1) was also required, but only at low irradiation doses. Importantly, mutation of genes encoding nucleotide excision repair pathway components severely disrupted both apoptosis and cell cycle arrest, suggesting that these genes not only participate in repair, but also signal the presence of damage to downstream components of the UV response pathway that we delineate here. Our study suggests that whereas DNA damage response pathways are conserved in metazoans in their general outline, there is significant evolution in the relative importance of individual checkpoint genes in the response to specific types of DNA damage.
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PMID:The nucleotide excision repair pathway is required for UV-C-induced apoptosis in Caenorhabditis elegans. 1734 67

Nbs1, a member of the Mre11-RAD50-Nbs1 complex, is phosphorylated by ATM, the product of the ataxia-telangiectasia mutated gene and a member of the phosphatidylinositol 3-kinase-related family of serine-threonine kinases, in response to DNA double-strand breaks (DSBs) to regulate DNA damage checkpoints. Here we show that BCR/ABL stimulated Nbs1 expression by induction of c-Myc-dependent transactivation and protection from caspase-dependent degradation. BCR/ABL-related fusion tyrosine kinases (FTKs) such as TEL/JAK2, TEL/PDGFbetaR, TEL/ABL, TEL/TRKC, BCR/FGFR1, and NPM/ALK as well as interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and stem cell factor (SCF) also stimulated Nbs1 expression. Enhanced ATM kinase-dependent phosphorylation of Nbs1 on serine 343 (S343) in response to genotoxic treatment was detected in leukemia cells expressing BCR/ABL and other FTKs in comparison to normal counterparts stimulated with IL-3, GM-CSF, and SCF. Expression of Nbs1-S343A mutant disrupted the intra-S-phase checkpoint, decreased homologous recombinational repair (HRR) activity, down-regulated XIAP expression, and sensitized BCR/ABL-positive cells to cytotoxic drugs. Interestingly, inhibition of Nbs1 phosphorylation by S343A mutant enhanced the antileukemia effect of the combination of imatinib and genotoxic agent.
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PMID:Enhanced phosphorylation of Nbs1, a member of DNA repair/checkpoint complex Mre11-RAD50-Nbs1, can be targeted to increase the efficacy of imatinib mesylate against BCR/ABL-positive leukemia cells. 1743 Nov 32

The p53 protein is one of the major tumor suppressor proteins. In response to DNA damage, p53 is prevented from degradation and accumulates to high levels. Ionizing radiation leads to hypophosphorylation of the p53 ubiquitin ligase Mdm2 at sites where phosphorylation is critical for p53 degradation and to the phosphorylation and activation of Akt/PKB, a kinase that phosphorylates and inhibits GSK-3. GSK-3, which normally phosphorylates Mdm2, is inactivated in response to ionizing radiation. We show that p53 accumulates in lymphoblasts from patients with the hereditary disorder ataxia telangiectasia in response to ionizing radiation despite the absence of a functional ATM kinase. Also, knockdown of ATR did not prevent p53 accumulation in response to ionizing radiation. Instead, p53 stabilization in response to ionizing radiation depended on the inactivation of GSK-3 and the presence of Akt/PKB. Akt/PKB is a target of DNA-PK, a kinase that is activated after ionizing radiation. Correspondingly, down-regulation of DNA-PK prevented phosphorylation of Akt/PKB and GSK-3 after ionizing radiation and strongly reduced the accumulation of p53. We therefore propose a signaling cascade for the regulation of p53 in response to ionizing radiation that involves activation of DNA-PK and Akt/PKB and inactivation of GSK-3 and Mdm2.
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PMID:p53 stabilization in response to DNA damage requires Akt/PKB and DNA-PK. 1850 46

CLK-2/TEL2 is essential for viability from yeasts to vertebrates, but its essential functions remain ill defined. CLK-2/TEL2 was initially implicated in telomere length regulation in budding yeast, but work in Caenorhabditis elegans has uncovered a function in DNA damage response signalling. Subsequently, DNA damage signalling defects associated with CLK-2/TEL2 have been confirmed in yeast and human cells. The CLK-2/TEL2 interaction with the ATM and ATR DNA damage sensor kinases and its requirement for their stability led to the proposal that CLK-2/TEL2 mutants might phenocopy ATM and/or ATR depletion. We use C. elegans to dissect developmental and cell cycle related roles of CLK-2. Temperature sensitive (ts) clk-2 mutants accumulate genomic instability and show a delay of embryonic cell cycle timing. This delay partially depends on the worm p53 homolog CEP-1 and is rescued by co-depletion of the DNA replication checkpoint proteins ATL-1 (C. elegans ATR) and CHK-1. In addition, clk-2 ts mutants show a spindle orientation defect in the eight cell stages that lead to major cell fate transitions. clk-2 deletion worms progress through embryogenesis and larval development by maternal rescue but become sterile and halt germ cell cycle progression. Unlike ATL-1 depleted germ cells, clk-2-null germ cells do not accumulate DNA double-strand breaks. Rather, clk-2 mutant germ cells arrest with duplicated centrosomes but without mitotic spindles in an early prophase like stage. This germ cell cycle arrest does not depend on cep-1, the DNA replication, or the spindle checkpoint. Our analysis shows that CLK-2 depletion does not phenocopy PIKK kinase depletion. Rather, we implicate CLK-2 in multiple developmental and cell cycle related processes and show that CLK-2 and ATR have antagonising functions during early C. elegans embryonic development.
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PMID:Functional dissection of Caenorhabditis elegans CLK-2/TEL2 cell cycle defects during embryogenesis and germline development. 1936 Jan 21

Regulation of gene expression at the translational level is particularly essential during developmental periods, when transcription is impaired. According to the closed-loop model of translational initiation, we have analyzed components of the 5 -mRNA cap-binding complex eIF4F (eIF4E, eIF4G, eIF4A), the eIF4E repressor 4E-BP1, and 3 -mRNA poly-(A) tail-associated proteins (PABP1 and 3, PAIP1 and 2, CPEB1, Maskin) during in vitro maturation of bovine oocytes and early embryonic development up to the 16-cell stage. Furthermore, we have elucidated the activity of distinct kinases which are potentially involved in their phosphorylation. Major phosphorylation of specific target sequences of PKA, PKB, PKC, CDKs, ATM/ATR, and MAPK were observed in M II stage oocytes. Furthermore, main changes in the abundance and/or phosphorylation of distinct mRNA-binding factors occur at the transition from M II stage oocytes to 2-cell embryos. In conclusion, the results indicate that, at the transition from oocyte to embryonic development, translational initiation is regulated by striking differences in the abundance and/or phosphorylation of 5 -end and 3 -end mRNA associated factors, mainly the poly-(A) bindings proteins PABP1 and 3, their repressor PAIP2 and a Maskin-like protein with distinct eIF4E-binding properties which prevents eIF4E/cap binding and eIF4F formation in vitro. Nevertheless, from the M II stage to 16-cell embryos a substantial amount of eIF4E and, to a lesser extent, of eIF4G was precipitated by (7)m-GTP-Separose indicating eIF4F complex formation. Therefore, it is likely that in general the reduction in PABP1 and 3 abundance represses overall translation during early embryonic development.
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PMID:Analysis of mRNA associated factors during bovine oocyte maturation and early embryonic development. 1969 62

In this study, using an in vitro human tumor model, we show that non-small lung adenocarcinoma A549 cells after treatment with DNA damaging antitumor drugs become permanently growth-arrested as a result of so-called drug-induced premature senescence (pseudo-senescence). However, a small fraction of drug-treated cells escapes pseudo-senescence that leads to re-growth of tumor cell population after drug treatment. We show that this re-growth is associated with the presence of cancer stem cells (CSCs) in lung tumor cell population. We also document that re-growth of CSCs can be greatly delayed if lung tumor cells are treated with drug/caffeine combination that leads to the inhibition of the ATM/ATR pathway and decreased phosphorylation of PKB/Akt at Ser473. We show that in non-treated A549 cells caffeine by itself induces a reversible growth arrest that is associated with increased fraction of so-called side population cells, containing CSCs. These results point to the existence of an unknown, caffeine-sensitive mechanism that controls the number of CSCs in lung tumor cell population. Full characterization of this mechanism may lead to the development of innovative cancer therapies, which are based on small molecular weight inhibitors of CSC differentiation and self-renewal, which mimic caffeine action. Our results have also important implications for drug screening tumor models in vitro.
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PMID:Cancer stem cells and escape from drug-induced premature senescence in human lung tumor cells: implications for drug resistance and in vitro drug screening models. 1973 35

Our knowledge on immortalization and telomere biology is mainly based on genetically manipulated cells analyzed before and many population doublings post growth crisis. The general view is that growth crisis is telomere length (TL) dependent and that escape from crisis is coupled to increased expression of the telomerase reverse transcriptase (hTERT) gene, telomerase activity upregulation and TL stabilization. Here we have analyzed the process of spontaneous immortalization of human T cells, regarding pathways involved in senescence and telomerase regulation. Two Nijmegen breakage syndrome (NBS) T cell cultures (S3R and S4) showed gradual telomere attrition until a period of growth crisis followed by the outgrowth of immortalized cells. Whole genome expression analysis indicated differences between pre-, early post- and late postcrisis cells. Early postcrisis cells demonstrated a logarithmic growth curve, very short telomeres and, notably, no increase in hTERT or telomerase activity despite downregulation of several negative hTERT regulators (e.g. FOS, JUN D, SMAD3, RUNX2, TNF-a and TGFb-R2). Thereafter, cMYC mRNA increased in parallel with increased hTERT expression, telomerase activity and elongation of short telomeres, indicating a step-wise activation of hTERT transcription involving reduction of negative regulators followed by activation of positive regulator(s). Gene expression analysis indicated that cells escaped growth crisis by deregulated DNA damage response and senescence controlling genes, including downregulation of ATM, CDKN1B (p27), CDKN2D (p19) and ASF1A and upregulation of CDK4, TWIST1, TP73L (p63) and SYK. Telomerase upregulation was thus found to be uncoupled to escape of growth crisis but rather a later event in the immortalization process of NBS T cell cultures.
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PMID:Telomerase upregulation is a postcrisis event during senescence bypass and immortalization of two Nijmegen breakage syndrome T cell cultures. 2008 18


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