Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Compelling experimental and epidemiological evidence involves oxygen radicals in carcinogenesis, acting reactive oxygen species both as endogenous genotoxins during cell initiation and as messenger molecules in mitogenesis and in tumor promotion. Moreover, oxidants stimulate neoangiogenesis, which is a prerequisite for tumor growth. However, while several natural as well as synthetic antioxidant compounds appear to be chemopreventive in mutagenicity assays, antioxidant-based treatments for the prevention or cure of cancer have led to non-conclusive if not disappointing results. This is likely due to the fact that oxygen radicals have also a major role in the natural defences against the propagation of cancer cells, i.e. tumor cell apoptosis and immune surveillance, and mediate the beneficial cytotoxic effect of both the chemo-and radio-therapy. In recent years, the mitochondrial antioxidant enzyme, Manganous Superoxide Dismutase (MnSOD), has received a growing attention as a negative modulator of cellular apoptosis and as a survival factor for cancer cells. In fact, while overexpression of this enzyme in cancer cells decreases proliferation and tumor incidence in transgenic models, it is clear that even small amounts of this enzyme are crucial for cell resistance to inflammatory stimuli and anticancer drugs, and prevent oncogene-induced apoptosis triggered by the tumor suppressor protein p53. A previously unexpected oncogenic potential of MnSOD is also suggested by the elevated levels of this enzyme in several classes of human neoplasms, in a fashion which often correlates with the degree of their malignancy. This review focuses on the debated issue of the pro- and/or anti-tumoral effect of MnSOD, with special emphasis on recent observations suggesting that pharmacological inhibition of MnSOD may represent an effective strategy to selectively kill cancer cells and to circumvent their resistance to the commonly used anticancer treatments.
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PMID:Mitochondrial superoxide dismutase: a promising target for new anticancer therapies. 1513 21

Caveolin-1 is an essential structural constituent of caveolae that has been implicated in mitogenic signaling and oncogenesis. Utilizing MCF-7 human breast cancer cells, stably transfected with caveolin-1 (MCF-7/Cav1), we previously demonstrated that caveolin-1 expression decreases MCF-7 cell proliferation and colony formation in soft agar. However, the loss of anchorage-independent growth is associated with inhibition of anoikis, as MCF-7/Cav1 cells exhibit increased survival after detachment. Herein we show that this phenotype is associated with suppression of detachment-induced activation of p53 and of the consequent induction of cyclin-dependent kinase inhibitor p21(WAF1/Cip1). In contrast, activation of p53 and p21(WAF1/Cip1) induced by doxorubicin in MCF-7/Cav1 cells remains largely unaffected. The phenotypic changes observed in MCF-7/Cav1 cells are not accompanied by changes in caspase-6, -7, -8 and -9 and cannot be explained by changes in Bid and Bcl-2 expression. However, MCF-7/Cav1 cells exhibit a constitutively phosphorylated Akt kinase and at least one phosphorylated high molecular weight putative Akt substrate which we designated pp340. In addition, MCF-7/Cav1 cells exhibit elevated expression of insulin-like growth factor-I (IGF-I) receptor expression and increased IGF-I signaling to Erk1/2 and to Akt, as well as IGF-I-induced stimulation of pp340 phosphorylation. The addition of IGF-I to the medium rescues the parental MCF-7 cells from anoikis, indicating that IGF-1 can act as a survival factor for suspended MCF-7 cells. Finally, the levels of caveolin-1 are dramatically elevated in a time-dependent manner upon detachment of anoikis-resistant MCF-7/Cav1 cells and HT-29-MDR human multidrug resistant colon cancer cells. We conclude that expression of caveolin-1 in human breast cancer cells enhances matrix-independent cell survival that is mediated by upregulation of IGF-I receptor expression and signaling.
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PMID:Caveolin-1 inhibits cell detachment-induced p53 activation and anoikis by upregulation of insulin-like growth factor-I receptors and signaling. 1559 98

VEGF is a specific mitogen and survival factor for endothelial cells and a key promoter of angiogenesis in physiological and pathological conditions. Nevertheless, VEGF tissue evaluation in cancer patients as a prognostic factor compared to the conventional histological and biological parameters is still controversial. In this case-control study, tissue VEGF was retrospectively determined by immunohistochemistry and related to T, N, ER, PgR, c-erbB-2, p53, MIB-1 and cyclin D1 in 129 breast cancer patients. Seventy-four of these patients had developed distant metastases postoperatively. The remaining 55 patients had remained disease-free >10 years after surgery. In 17 (13%) of the 129 patients (six with distant metastases and eleven disease-free) tissue and plasma VEGF were concomitantly evaluated. In univariate analysis no significant differences in VEGF and tumor size were found between metastatic and disease-free patients, whereas there were significant differences in N, ER, PgR, c-erbB-2, p53, MIB-1 and cyclin D1 (p ranging from 0.001 to 0.0001). In multivariate analysis VEGF showed less significance than N, ER, c-erbB-2, MIB-1 and cyclin D1 (p = 0.012, p = 0.007, p = 0.005, p = 0.005, p = 0.002 and p = 0.001, respectively). VEGF was a significant unfavorable prognostic indicator only in the N+ subset (p = 0.015), while ER (p = 0.05 and p = 0.021) and MIB-1 (p = 0.031 and p = 0.022) were significant in both the N+ and N- subgroups. In multivariate analysis in the 74 metastatic cases VEGF did not show any significance in relation to disease-free interval and overall survival from the time of mastectomy and from the time of relapse, whereas N and PgR did (p ranging from 0.018 to 0.001). In conclusion, tissue VEGF does not seem a suitable candidate to replace conventional histological and other common biological prognostic factors in breast cancer.
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PMID:Vascular endothelial growth factor (VEGF) and other common tissue prognostic indicators in breast cancer: a case-control study. 1564 33

The physical and functional interaction between the transcription factor p53 and its negative regulatory partner protein Hdm2 (Mdm2 in mouse) is a key point of convergence of multiple signaling pathways that regulates cell proliferation and survival. hdm2 mRNA transcription is induced by p53, forming the basis of an auto-regulatory feedback loop. Growth and survival factor-activated Ras-Raf-MEK-ERK signaling can also regulate Hdm2 expression independently of p53, contributing to the pro-survival effect of these factors. In murine fibroblasts, this occurs through the regulation of mdm2 mRNA transcription. Here we show that, in human breast cancer epithelial cells, MEK-dependent regulation of Hdm2 expression also occurs at a post-transcriptional level. Pharmacological blockade of MEK activity in T47D cells inhibits Hdm2 protein synthesis by 80-90%. This occurs in the absence of changes in the expression of the major hdm2-P1 mRNA transcript and only an approximately 40% reduction in hdm2-P2 transcript levels. The amounts of both transcripts that are associated with polyribosomes and are, hence, being actively translated are reduced by >80% by the MEK inhibitor, U0126. We show here that this is due to the inhibition of hdm2 mRNA export from the nucleus when MEK activity is inhibited. In MCF-7 breast cancer cells that express wild-type p53, Hdm2 is required to suppress p53-dependent transcription when MEK kinase is active. Regulation of the nuclear export of hdm2 mRNA provides, therefore, a mechanism whereby mitogen-stimulated cells avoid p53-dependent cell cycle arrest or apoptosis by maintaining the dynamic equilibrium of the Hdm2-p53 feedback loop.
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PMID:MEK-ERK signaling controls Hdm2 oncoprotein expression by regulating hdm2 mRNA export to the cytoplasm. 1572 37

Angiopoietin-1 (Ang-1) is essential for the maturation of blood vessels during vasculogenesis. Besides angiogenesis, recent publications indicate that Ang-1 is also a potent survival factor for endothelial cells; however, the mechanisms by which pathways remain elusive. Doxorubicin (DOX) is a powerful anticancer drug, but its use is severely restricted by its cardiotoxicity. The authors report here that Ang-1 inhibits DOX-induced cell death in human umbilical vein endothelial cells (HUVECs). Interestingly, the DOX-induced up-regulation in Fas (CD95/APO-1) and Fas ligand expression could be blocked by Ang-1, indicating a pivotal role of Ang-1 in DOX-induced Fas and Fas ligand expression. In addition, the prevention of cell death in this model system seems to be dependent on the activation of phosphatidylinositol 3-kinase (PI3K)/Akt, as Ang-1 fails to inhibit DOX-induced cell death while PI3K/Akt pathway was blocked by the PI3K inhibitor LY294002. Moreover, Ang-1 inhibits DOX-induced up-regulation of p53 through PI3K/Akt. Therefore, Ang-1 is a potent inhibitor for DOX-induced cell death through Fas and PI3K/Akt-mediated pathways.
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PMID:Angiopoietin-1 inhibits doxorubicin-induced human umbilical vein endothelial cell death by modulating fas expression and via the PI3K/Akt pathway. 1576 44

YKL-40 is a 40 kDa secreted glycoprotein belonging to the family of 'mammalian chitinase-like proteins', but without chitinase activity. YKL-40 has a proliferative effect on fibroblasts, chondrocytes and synoviocytes, and chemotactic effect on endothelium and vascular smooth muscle cells. Elevated YKL-40 levels are found in serum of patients with diseases characterized by inflammation, fibrosis and tissue remodeling. Several studies have reported that high serum YKL-40 levels in patients with cancer are associated with poor prognosis. YKL-40 expression is strongly elevated in serum and biopsy material from glioblastomas patients. We investigated the expression of YKL-40 in three human malignant glioma cell lines exposed to different types of stress. Whereas a polymerase chain reaction transcript was detectable in all three cell lines, only U87 produced measurable amounts of YKL-40 protein. In U87, hypoxia and ionizing radiation induced a significant increase in YKL-40 after 24-48 h. The hypoxic induction of YKL-40 was independent of HIF1. Etoposide, ceramide, serum depletion and confluence all led to elevated YKL-40. Inhibition of p53 augmented the YKL-40 expression indicating that YKL-40 is attenuated by p53. In contrast, both basic fibroblast growth factor and tumor necrosing factor-alpha repressed YKL-40. These are the first data on regulation of YKL-40 in cancer cells. Diverse types of stress resulted in YKL-40 elevation, which strongly supports an involvement of YKL-40 in the malignant phenotype as a cellular survival factor in an adverse microenvironment.
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PMID:Regulation of YKL-40 expression during genotoxic or microenvironmental stress in human glioblastoma cells. 1577 22

Classical Hodgkin lymphomas (cHL) have now been recognized as B-cell lymphomas with some exceptional cases of T-cell origin. In recent years, there has been accumulating evidence that Hodgkin and Reed-Sternberg (H/RS) cells, the presumed neoplastic-cell population in cHL, are characterized by a profound disturbance of the cell cycle and apoptosis regulation. The constitutive activation of the nuclear factor (NF)-kappaB pathway, which is considered to be involved in the proliferation and survival of H/RS cells. Moreover, substantial evidence that H/RS cells have defective cell cycle and apoptosis regulation has been provided by studies showing that these cells are characterized, in a large proportion of cases, by alterations of the p53, Rb and p27 tumor suppressor pathways, overexpression of cyclins involved in the G1/S and G2/M transition such as cyclins E, D2, D3, A and B1, overexpression of cyclin-dependent kinases such as CDK1, 2 and 6 and overexpression of anti-apoptotic proteins such as c-FLIP, bcl-xl, c-IAP2, X-linked I4P and survivin. Recent studies suggest that interleukin 13 (IL-13) is an important growth and survival factor in H/RS cells. Furthermore, the Epstein-Barr Virus (EBV), which is present in H/RS cells in about 30-50% of cHL, has been shown to affect the cell cycle and apoptosis regulation in cHL. The present review summarizes data with respect to the cell cycle and apoptosis deregulation in cHL.
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PMID:Cell cycle and apoptosis deregulation in classical Hodgkin lymphomas. 1579 9

IL-6 is a growth and survival factor for myeloma cells, although the mechanism by which it induces myeloma cell proliferation through gene expression is largely unknown. Microarray analysis showed that some B-cell lymphoma-associated oncogenes such as Bcl6, which is absent in normal plasma cells, were upregulated by IL-6 in IL-6-dependent myeloma cell lines. We found that Bcl6 variant 2 was upregulated by STAT3. ChIP assay and EMSA showed that STAT3 bound to the upstream region of variant 2 DNA. Expression of p53, a direct target gene of Bcl6, was downregulated in the IL-6-stimulated cells, and this process was impaired by an HDAC inhibitor. Bcl6 was knocked down by introducing small hairpin RNA, resulting in decreased proliferation and increased sensitivity to a DNA damaging agent. Thus, STAT3-inducible Bcl6 variant 2 appears to generate an important IL-6 signal that supports proliferation and survival of IL-6-dependent myeloma cells.
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PMID:IL-6-induced Bcl6 variant 2 supports IL-6-dependent myeloma cell proliferation and survival through STAT3. 1618 30

The role of insulin-like growth factor (IGF-1) as neural survival factor for the treatment of Alzheimer's disease has recently gained attention. The present study shows that IGF-1 protects lymphocytes from (10, 30 microM) Abeta[(25-35)] and (25, 50, 100 microM) H(2)O(2)-induced apoptosis through NF-kappaB activation and p53 down regulation involving the phosphoinositide 3-kinase (PI-3K)-dependent pathway as demonstrated by using either (25 microM) LY294002 (PI-3K inhibitor), (10 nM) ammonium pyrrolidinedithiocarbamate (PDTC; NF-kappaB inhibitor), 50 nM pifithrin-alpha (PFT; p53 inhibitor) or by using immunocytochemistry detection of NF-kappaB and p53 transcription factors activation. Importantly, IGF-1, PDTC and PFT were able to protect and rescue lymphocytes pre-exposed to 10 muM Abeta[(25-35)], even when the three compounds were added up-to 12 h post- Abeta[(25-35)] exposure. Altogether these results suggest that survival/rescue of lymphocytes from Abeta[(25-35)] toxicity is determined by p53 inactivation via IGF-1/ PI-3K pathway.
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PMID:Insulin-like growth factor-1 prevents Abeta[25-35]/(H2O2)- induced apoptosis in lymphocytes by reciprocal NF-kappaB activation and p53 inhibition via PI3K-dependent pathway. 1639 95

We demonstrate that deltaNp63alpha is an essential survival factor in head and neck squamous cell carcinoma (HNSCC) through its ability to suppress p73-dependent apoptosis. Inhibition of endogenous p63 expression by RNAi induces apoptosis selectively in HNSCC cells that overexpress deltaNp63alpha. Knockdown of p63 induces the proapoptotic bcl-2 family members Puma and Noxa, and both their induction and subsequent cell death are p53 independent but require transactivating isoforms of p73. Inhibition of p73-dependent transcription by deltaNp63alpha involves both direct promoter binding and physical interaction with p73. In HNSCC cells lacking endogenous deltaNp63alpha expression, bcl-2 is instead upregulated and can suppress p73-mediated death. Together, these data define a pathway whereby deltaNp63alpha promotes survival in squamous epithelial malignancy by repressing a p73-dependent proapoptotic transcriptional program.
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PMID:p63 mediates survival in squamous cell carcinoma by suppression of p73-dependent apoptosis. 1641 63


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