Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0684249 (lung carcinoma)
 23,830 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidermal growth factor (EGF) plays a major role in non-small cell lung cancer cell autocrine growth and has been reported to activate the JUN kinase/stress-activated protein kinase (JNK/SAPK) pathway in model cells. Activation of JNK/SAPK leads to the phosphorylation of c-JUN protooncogene on serines 63 and 73. This mechanism is required for and cooperates in the transformation of rat embryo fibroblasts by Ha-RAS. However, the function of JNK/SAPK in human tumor growth is unknown. We have tested several lung carcinoma cell lines. All exhibited UV-C-inducible JNK/SAPK activity; two exhibited constitutive activity in low serum, and two (M103 and A549) exhibited EGF-inducible JNK/SAPK activity. In A549 cells, EGF induced a rapid and prolonged (up to 24 h) activation of the JNK/SAPK pathway that correlated with a 150-190% growth stimulation. Stably transfected clones of A549 cells expressing c-JUN(S63A,S73A), a transdominant inhibitor of c-JUN, completely blocked the EGF-stimulated proliferation effect but did not alter the basal proliferation rate. Consistent with these results JNK antisense oligonucleotides targeted to JNK1 and JNK2 entirely eliminated the EGF-stimulated JNK/SAPK activity and blocked EGF-stimulated growth but not basal growth. In contrast, specific inhibition of the RAF/ERK pathway by PD98059 (MEK1 inhibitor) completely blocked ERK activation by EGF and basal cell growth but not EGF-stimulated growth, thereby dissociating the growth-promoting roles of each pathway. Our observations indicate, for the first time, that JNK/SAPK may be a preferential effector pathway for the growth properties of EGF in A549 cells.
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PMID:The JUN kinase/stress-activated protein kinase pathway is required for epidermal growth factor stimulation of growth of human A549 lung carcinoma cells. 940 38

In this study we have explored the involvement of oxidative stress in Cr(VI)-induced JNK, p38 and ERK signaling pathways and their effects on Cr(VI) cytotoxicity in human non-small cell lung carcinoma CL3 cells. Exposure to K(2)Cr(2)O(7) markedly activated JNK and p38 and moderately activated ERK in a dose- (10-80 microM) and time-dependent (1-12 h) manner. The activated p38 decreased markedly and rapidly and the activated JNK decreased gradually when Cr(VI) was removed from the medium. Post-incubation of Cr(VI)-treated cells with H(2)O(2) increased the activities of JNK and p38, but not ERK. Co-administering Cr(VI) with 3-amino-1,2, 4-triazole (3AT), a catalase inhibitor, enhanced p38 activation, but did not influence JNK and ERK activation by Cr(VI). Conversely, co-administering Cr(VI) with mannitol, a hydroxyl radical scavenger and a Cr(V) chelator, reduced p38 activation and increased JNK and ERK activation by Cr(VI). These results indicate that p38 activation by Cr(VI) is positively correlated with oxidative stress, while JNK activity can be enhanced by either a quencher (mannitol) or activator (H(2)O(2)) of redox reactions in Cr(VI)-exposed CL3 cells. However, both 3AT and mannitol reduced the cytotoxicity of Cr(VI), but H(2)O(2) did not. The JNK activated by Cr(VI) was decreased (approximately 50%) by expression of a kinase-defective form of MKK7 (MKK7A) but not that of MKK4 (MKK4KR), suggesting that activation of JNK by Cr(VI) is mediated through MKK7. SB202190, a specific inhibitor of p38, markedly decreased JNK but did not change ERK activation by Cr(VI). PD98059, a specific inhibitor of ERK kinases MKK1/2, blocked ERK and p38 but did not alter JNK activation by Cr(VI). Neither the specific kinase inhibitors nor expression of MKK7A altered Cr(VI)-induced cytotoxicity. Together, these results suggest that activation of the JNK, p38 and ERK pathways by Cr(VI) is mediated through diverse redox mechanisms, yet their activation does not correlate with Cr(VI) cytotoxicity.
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PMID:Activation of JNK, p38 and ERK mitogen-activated protein kinases by chromium(VI) is mediated through oxidative stress but does not affect cytotoxicity. 1091 Sep 49

Cellular response to oxidative stress is a complex process that is often connected to cell cycle regulation. The present study examines the effect of H(2)O(2) on cell cycle regulation and involvement of reactive oxygen species (ROS) in these H(2)O(2)-induced responses in a p53-deficient human lung carcinoma cell line, H1299. Treatment of the cells with H(2)O(2) caused a G2/M phase arrest. Among the redox-sensitive transcription factors, NF-kappaB and AP-1, we found that only AP-1 was activated by 200 microM H(2)O(2) in human lung cells. Furthermore, electrophoretic mobility shift assays revealed that H(2)O(2) enhanced the DNA binding of AP-1 to a putative AP-1 binding element (TGAGGAA) in the p21(WAF1/CIP1) promoter region (between -2203 and -2197 nucleotides upstream of the transcription initiation site). An increase in c-Jun phosphorylation by ERK was also found to accompany the increased AP-1 activity as detected by Western blot. PD98059, a specific inhibitor of MEK, diminished H(2)O(2)-induced phosphorylation of c-Jun and DNA binding activity of AP-1, decreased expression of p21(WAF1/CIP1), and released the cells from G2/M arrest. Taken together, these results revealed a novel AP-1 binding site in the promoter region of p21(WAF1/CIP1) and a possible cell cycle regulation mechanism mediated by activation of a redox-dependent ERK signaling pathway.
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PMID:H(2)O(2)-induced AP-1 activation and its effect on p21(WAF1/CIP1)-mediated G2/M arrest in a p53-deficient human lung cancer cell. 1205 10

Nanomolar concentrations of Taxol, and other antimitotic agents that interact with microtubules, mediate serine phosphorylation of the 66-kDa Shc isoform (p66shc) in A549 human lung carcinoma cells, 9-18 h after drug treatment. This event coincides with the release of PARP cleavage fragments that are early indicators of apoptosis. Taxol-induced serine phosphorylation of p66shc results from a MEK-independent signaling pathway that is activated in A549 cells that have a prolonged or abnormal mitotic phase of the cell cycle [Cancer Res. 60 (2000) 5171]. In contrast, in murine macrophage RAW 264.7 cells, micromolar concentrations of Taxol but not other microtubule-interacting agents induced serine phosphorylation of p66shc that correlated with the phosphorylation of Raf-1 and extracellular signal-regulated kinase (ERK1/2), within 15-30 min after Taxol treatment. This event also was induced by lipopolysaccharide (LPS). The MEK-inhibitor, U0126, that specifically inhibits the activation of ERK also blocked the phosphorylation of p66shc and Raf-1, suggesting that these processes were MEK-dependent, quite different from that which was observed in A549 cells. Taxol also induced phosphorylation of p38 and JNK MAP kinases within 8-15 min after drug treatment. It is known that Taxol, but not other microtubule-interacting agents, induces the production of cytokines, such as tumor necrosis factor alpha (TNF-alpha) in mouse macrophages. The time course of Taxol-induced TNF-alpha expression coincides with that of Taxol-induced p66shc phosphorylation, and U0126 inhibits significantly Taxol-induced TNF-alpha expression in RAW 264.7 cells. Our data indicate that the Taxol-induced serine phosphorylation of p66shc in RAW 264.7 cells is microtubule-independent and may be related to increased TNF-alpha expression after Taxol and LPS treatment. It is concluded that the mechanisms involved in Taxol-induced p66shc phosphorylation are distinct in A549 and RAW 264.7 cells.
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PMID:Distinct mechanisms of taxol-induced serine phosphorylation of the 66-kDa Shc isoform in A549 and RAW 264.7 cells. 1206 70

Human tissue factor pathway inhibitor-2 (hTFPI-2) is a 32-kDa serine protease inhibitor that is associated with the extracellular matrix. hTFPI-2 inhibits several extracellular matrix-degrading serine proteases and may play a role in tumor invasion and metastasis. To study the signal transduction pathway that leads to the activation of the hTFPI-2, we cloned the potential promoter region of this gene adjacent to a heterologous luciferase reporter gene. Phorbol 12-myristate 13-acetate (PMA) induced the luciferase reporter gene in HEK293 cells and other epithelial cell lines, such as the human lung carcinoma A549 cells, the breast carcinoma MCF7 cells, and the cervical HeLa cells. This PMA induction was blocked with the MEK inhibitor UO126, suggesting that the PMA-induced activation of the hTFPI-2 promoter is mediated through MEK. Furthermore, epidermal growth factor induced the luciferase reporter gene in HeLa cells. Cotransfection of the luciferase construct with constitutively active components of the Ras/Raf/MEK/ERK pathway in EcR-293 cells lead to a 7- to 92-fold induction of the luciferase reporter gene, indicating that regulation of hTFPI-2 is mediated through this pathway. A series of luciferase reporter gene constructs with progressive deletions of the 5'-flanking region suggested that the minimal basal promoter activity is located between nucleotide positions -89 and -384, whereas the minimal inducible promoter activity is between -89 and -222. We have used the computer program TFSEARCH and mutagenesis to analyze potential transcription factor binding sites. We identified an AP-1 binding site at nucleotide position -156 (inducible activity) and a Sp1 site at position -134 (basal activity) as potential cis-acting elements in the promoter region of the hTFPI-2.
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PMID:The ERK/MAPK pathway regulates the activity of the human tissue factor pathway inhibitor-2 promoter. 1244 83

The molecular events associated with apoptosis induced by two distinct triggers (1) serum withdrawal and (2) etoposide treatment were investigated in the human lung carcinoma cell line A549. Although both serum withdrawal and etoposide treatment resulted in internucleosomal DNA fragmentation, the morphologic features were distinct. Serum deprived apoptotic cells appeared small, round and refractile, with little evidence of nuclear fragmentation; etoposide-induced apoptotic cells appeared enlarged and flattened and displayed prominent nuclear fragmentation. p53 and p21/waf1 protein levels were elevated in etoposide-treated cells, but not in cells subjected to serum with-drawal. Apoptosis induced by both treatments was accompanied by a significant reduction in Rb protein levels. However, etoposide treatment led to hypo-phosphorylation of Rb, while serum withdrawal did not alter the Rb phosphorylation pattern. Serum withdrawal-induced apoptosis was correlated with activation of JNK and suppression of ERK activities, while both JNK and ERK activities were slightly elevated during etoposid- induced apoptosis. Together, these results support the hypothesis that apoptosis induced by serum withdrawal and etoposide treatment occurs through different pathways and involves distinct mediators.
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PMID:Serum withdrawal and etoposide induce apoptosis in human lung carcinoma cell line A549 via distinct pathways. 1464 55

The matrix metalloproteinase (MMP)-2 has been recognized as a major mediator of basement membrane degradation, angiogenesis, tumor invasion, and metastasis. The factors that regulate its expression have not, however, been fully elucidated. We previously identified the type I insulin-like growth factor (IGF-I) receptor as a regulator of MMP-2 synthesis. The objective of the present study was to investigate the signal transduction pathway(s) mediating this regulation. We show here that in Lewis lung carcinoma subline H-59 cells treated with IGF-I (10 ng/ml), the PI 3-kinase (phosphatidylinositol 3'-kinase) /protein kinase B (Akt) and C-Raf/ERK pathways were activated, and MMP-2 promoter activity, mRNA, and protein synthesis were induced. MMP-2 induction was blocked by the PI 3-kinase inhibitors LY294002 and wortmannin, by overexpression of a dominant-negative Akt or wild-type PTEN (phosphatase and tensin homologue deleted on chromosome 10), and by rapamycin. In contrast, a MEK inhibitor PD98059 failed to reduce MMP-2 promoter activation and actually increased MMP-2 mRNA and protein synthesis by up to 30%. Interestingly, suppression of PI 3-kinase signaling by a dominant-negative Akt enhanced ERK activity in cells stimulated with 10 ng/ml but not with 100 ng/ml IGF-I. Furthermore, at the higher (100 ng/ml) IGF-I concentration, C-Raf and ERK, but not PI 3-kinase activation, was enhanced, and this resulted in down-regulation of MMP-2 synthesis. This effect was reversed in cells expressing a dominant-negative ERK mutant. The results suggest that IGF-I can up-regulate MMP-2 synthesis via PI 3-kinase/Akt/mTOR (the mammalian target of rapamycin) signaling while concomitantly transmitting a negative regulatory signal via the Raf/ERK pathway. The outcome of IGF-IR (the receptor for IGF-I) activation may ultimately depend on factors, such as ligand bioavailability, that can shift the balance preferentially toward one pathway or the other.
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PMID:Dual regulation of MMP-2 expression by the type 1 insulin-like growth factor receptor: the phosphatidylinositol 3-kinase/Akt and Raf/ERK pathways transmit opposing signals. 1499 22

Non-small cell lung carcinoma (NSCLC) is characterized by resistance to drug-induced apoptosis, which might explain the survival of lung cancer cells following treatment. Recently we have shown that the broad-range kinase inhibitor staurosporine (STS) reactivates the apoptotic machinery in U1810 NSCLC cells [Joseph et al., Oncogene 21 (2002) 65]. Lately, several STS analogs that are more specific in kinase inhibition have been suggested for tumor treatment. In this study the apoptosis-inducing ability of the STS analogs PKC 412 and Ro 31-8220 used alone or in combination with DNA-damaging agents in U1810 cells was investigated. In these cells Ro 31-8220 neither induced apoptosis when used alone, nor sensitized cells to etoposide treatment. PKC 412 as a single agent induced death of a small number of U1810 cells, whereas it efficiently triggered a dose- and time-dependent apoptosis in U1285 small cell lung carcinoma cells. In both cell types PKC 412 triggered release of mitochondrial proteins followed by caspase activation. However, concomitant activation of a caspase-independent pathway was essential to kill NSCLC cells. Importantly, PKC 412 was able to sensitize etoposide- and radiation-induced death of U1810 cells. The best sensitization was achieved when PKC 412 was administered 24 h after treatments. In U1810 cells, Ro 31-8220 decreased PMA-induced ERK phosphorylation as efficiently as PKC 412, indicating that the failure of Ro 31-8220 to induce apoptosis was not due to weaker inhibition of conventional and novel PKC isoforms. However, Ro 31-8220 increased the basal level of ERK and Akt phosphorylation in both cell lines, whereas Akt phosphorylation was suppressed in the U1810 cells, which might influence apoptosis. These results suggest that PKC 412 could be a useful tool in increasing the efficiency of therapy of NSCLC.
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PMID:PKC 412 sensitizes U1810 non-small cell lung cancer cells to DNA damage. 1577

The Ras-Raf-MAPK pathway has been implicated in lung carcinogenesis and, potentially, the maintenance of the malignant phenotype in these tumors. Mutations in ras and B-raf genes have been described in lung cancer, representing one of the few examples of tandem mutations in a signaling cascade. As a result, numerous approaches to inhibiting this pathway in lung cancer have been explored in the past decade. The most promising approach to date appears to be the inhibition of mitogen-activated ERK kinase or MEK. In this review, the potential utility of MEK inhibitors in the therapy of lung cancer is discussed.
Clin Lung Cancer 2005 Nov
PMID:The role of mitogen-activated ERK-kinase inhibitors in lung cancer therapy. 1635 19

COX-2 has been implicated in the control of human non-small cell lung carcinoma (NSCLC) cell growth. The mechanisms by which COX-2 exerts its mitogenic effects have not been entirely elucidated, but stimulation of prostaglandin E2 production and alterations in the expression of the cyclin-dependent kinase inhibitor p21(WAF-1/CIP1/MDA-6)(p2i) have been suggested. Here, we demonstrate that two COX-2 inhibitors (NS398 and Nimesulide) inhibit proliferation and induce apoptosis in NSCLC cells, and these effects were associated with induction of p21 mRNA and protein expression. However, the anti-growth effect of the COX-2 inhibitors and their ability to induce p21 were not affected by COX-2 siRNA suggesting that their actions were COX-2 independent. Instead, activation of the MEK-1/Erk pathway was necessary since COX-2 inhibitors stimulated the phosphorylation of ERKs, and their effects were blocked by PD98095, an inhibitor of this pathway. Furthermore, we show that both NS398 and Nimesulide induced p21 gene promoter activity and this was prevented by PD98095. COX-2 inhibitors increased nuclear protein binding to the Spl site in the promoter region of the p21 gene. Consistent with a role for p21, we found that p21 antisense oligonucleotides prevented the effects of COX-2 inhibitors on cell growth. In summary, our results suggest that COX-2 inhibitors suppress NSCLC cell growth by inducing the expression of the p21 gene through MEK-1/ERK signaling and DNA-protein interactions involving Spl. These observations unveil a mechanism for p21 gene regulation by COX-2 inhibitors in lung carcinoma cell growth and this pathway represents a potential target for therapy.
Lung Cancer 2006 Mar
PMID:COX-2 inhibitors suppress lung cancer cell growth by inducing p21 via COX-2 independent signals. 1637 53


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