Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polo-like kinase 1 (Plk1) has an important role in the regulation of M phase of the cell cycle. In addition to its cell cycle-regulatory function, Plk1 has a potential role in tumorigenesis. Here we found for the first time that Plk1 physically binds to the tumor suppressor p53 in mammalian cultured cells, and inhibits its transactivation activity as well as its pro-apoptotic function. During the cisplatin-induced apoptosis in human neuroblastoma SH-SY5Y cells, the expression level of Plk1 was significantly decreased both at mRNA and protein levels, whereas cisplatin treatment caused a remarkable stabilization of p53. Systematic immunoprecipitation analyses using a series of deletion mutants of p53 revealed that a sequence-specific DNA-binding region of p53 is required and sufficient for the physical interaction with Plk1. The ectopically overexpressed Plk1 was co-localized with the endogenous p53 in mammalian cell nucleus, as shown by confocal laser microscopy. Expression of exogenous Plk1 and p53 in p53-deficient lung carcinoma H1299 cells greatly decreased the p53-mediated transcription from the p53-responsive p21(WAF1), MDM2, and BAX promoters, whereas the kinase-deficient mutant form of Plk1 failed to reduce the transcriptional activity of p53. Consistent with the luciferase reporter analysis, Plk1 had an ability to block the p53-dependent induction of the endogenous p21(WAF1). In addition, Plk1 inhibited the pro-apoptotic function of p53 in H1299 cells. Intriguingly, Plk1-mediated repression of p53 was attenuated with ATM. Thus, our present findings strongly suggest that p53 is a critical target of Plk1, and its function is abrogated through the physical interaction with Plk1.
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PMID:Polo-like kinase 1 (Plk1) inhibits p53 function by physical interaction and phosphorylation. 1502 21

Neuroblastoma is a childhood cancer arising from the sympathetic nervous system. Disseminated neuroblastoma has a poor prognosis despite intensive multimodality treatment. Histone deacetylases (HDACs) were recently discovered as a potential target for pharmacological gene therapy in cancer. HDACs have an important function in regulating DNA packaging in chromatin, thereby affecting the transcription of genes. In this paper, we tested the efficacy of a newly developed histone deacetylase inhibitor, BL1521, on neuroblastoma in vitro by investigating the changes in: acetylation of histone H3, in situ HDAC activity, p21(WAF1/CIP1) and MYCN expression, metabolic activity, proliferation, morphology and the amount of apoptosis present. BL1521 inhibited the in situ HDAC activity of a panel of neuroblastoma cell lines by at least 85%. Western analysis showed an increase of histone H3 acetylation in neuroblastoma cells after incubation with BL1521. Northern analysis showed an increase in the expression of p21(WAF1/CIP1) and a decrease in the expression of MYCN in neuroblastoma cells after incubation with BL1521. Proliferation as well as the metabolic activity of neuroblastoma cells decreased significantly in response to treatment with BL1521, regardless of the MYCN status of the cells. BL1521 induced poly-(ADP-ribose) polymerase cleavage in a time- and dose-dependent manner, indicating the induction of apoptosis. Furthermore, when compared to the HDAC inhibitors Trichostatin A and 4-phenylbutyrate, BL1521 has an intermediate efficacy. Our results show that BL1521 is a potent inhibitor of HDAC and that HDACs are an attractive target for selective chemotherapy in neuroblastoma.
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PMID:The novel histone deacetylase inhibitor BL1521 inhibits proliferation and induces apoptosis in neuroblastoma cells. 1534 17

One hallmark of Ewing's sarcoma/peripheral neuroectodermal tumors is the presence of the Ews/Fli-1 chimeric oncogene. Interestingly, infection of neuroblastoma tumor cell lines with Ews/Fli-1 switches the differentiation program of neuroblastomas to Ewing's sarcoma/peripheral neuroectodermal tumors. Here we examined the status of cytoplasmically sequestered wt-p53 in neuroblastomas after stable expression of Ews/Fli-1. Immunofluorescence revealed that in the neuroblastoma-Ews/Fli-1 infectant cell lines, p53 went from a punctate-pattern of cytoplasmic sequestration to increased nuclear localization. Western blot analysis revealed that PARC was down-regulated in one neuroblastoma cell line but not expressed in the second. Therefore, decreased PARC expression could not fully account for relieving p53 sequestration in the neuroblastoma tumor cells. Neuroblastoma-Ews/Fli-1 infectant cell lines showed marked increases in p53 protein expression without transcriptional up-regulation. Interestingly, p53 was primarily phosphorylated, without activation of its downstream target p21(WAF1). Western blot analysis revealed that whereas MDM2 gene expression does not change, p14(ARF), a negative protein regulator of MDM2, increases. These observations suggest that the downstream p53 pathway may be inactivated as a result of abnormal p53. We also found that p53 has an extended half-life in the neuroblastoma-Ews/Fli-1 infectants despite the retention of a wild-type sequence in neuroblastoma-Ews/Fli-1 infectant cell lines. We then tested the p53 response pathway and observed that the neuroblastoma parent cells responded to genotoxic stress, whereas the neuroblastoma-Ews/Fli-1 infectants did not. These results suggest that Ews/Fli-1 can directly abrogate the p53 pathway to promote tumorigenesis. These studies also provide additional insight into the relationship among the p53 pathway proteins.
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PMID:The Ews/Fli-1 fusion gene changes the status of p53 in neuroblastoma tumor cell lines. 1549 48

Histone deacetylase inhibitors (HDACi) have been discovered as potential drugs for cancer treatment. The effect of BL1521, a novel HDACi, on the cell cycle distribution and the induction of apoptosis was investigated in a panel of MYCN single copy and MYCN amplified neuroblastoma cell lines. BL1521 arrested neuroblastoma cells in the G1 phase and induced up to 30% apoptosis. Downregulation of CDK4, upregulation of p21(WAF1/CIP1) and an increase of hypophosphorylated retinoblastoma protein were observed, indicating a possible mechanism for the cell-cycle arrest. BL1521 also induced downregulation of p27, which may underlie the observed induction of apoptosis.
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PMID:Histone deacetylase inhibitor BL1521 induces a G1-phase arrest in neuroblastoma cells through altered expression of cell cycle proteins. 1573 67

Deregulation of the Rb/E2F pathway in human fibroblasts results in an E2F1-mediated apoptosis dependent on Atm, Nbs1, Chk2 and p53. Here, we show that E2F1 expression results in MRN foci formation, which is independent of the Nbs1 interacting region and the DNA-binding domain of E2F1. E2F1-induced MRN foci are similar to irradiation-induced foci (IRIF) that result from double-strand DNA breaks because they correlate with 53BP1 and gammaH2AX foci, do not form in NBS cells, do form in AT cells and do not correlate with cell cycle entry. In fact, we find that in human fibroblasts deregulated E2F1 causes a G1 arrest, blocking serum-induced cell cycle progression, in part through an Nbs1/53BP1/p53/p21(WAF1/CIP1) checkpoint pathway. This checkpoint protects against apoptosis because depletion of 53BP1 or p21(WAF1/CIP1) increases both the rate and extent of apoptosis. Nbs1 and p53 contribute to both checkpoint and apoptosis pathways. These results suggest that E2F1-induced foci generate a cell cycle checkpoint that, with sustained E2F1 activity, eventually yields to apoptosis. Uncontrolled proliferation due to Rb/E2F deregulation as well as inactivation of both checkpoint and apoptosis programs would then be required for transformation of normal cells to tumor cells.
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PMID:E2F1 induces MRN foci formation and a cell cycle checkpoint response in human fibroblasts. 1643 72

Neuroblastoma is a common solid tumor of children that arises from the sympathetic nervous system. Much work has consequently focused on the possibility of inducing marked cell death in neuroblastoma, and the new effective drugs are required. We have newly synthesized LB-18, closely related to lembehyne A (LB-A), a polyacetylene derived from a kind of marine sponge. LB-A has been shown to induce p21/WAF1 and causes G1 phase arrest in mouse neuroblastoma Neuro2A cells; however, we show here that LB-18 causes cell death in human neuroblastoma KP-N-TK cells in a dose-dependent manner. TUNEL assay and flow cytometric analysis showed that the cell death caused by LB-18 was associated with the DNA damage but the pan-caspase inhibitor, zVAD-fmk, could not prevent the cell death. Western blot analysis and cleavage of the caspase-3 or -7 substrate assay showed that LB-18 could not activate caspases 3, 7, 8 and 9. These results suggest that LB-18 causes caspase-independent cell death in human neuroblastoma cells. In the future, LB-18 may be useful for cancer therapeutics, especially for neuroblastoma.
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PMID:A novel synthetic drug, LB-18, closely related to lembehyne-A derived from a marine sponge, induces caspase-independent cell death to human neuroblastoma cells. 1677 97

Recently, we reported that GM-CSF showed therapeutic effects on the spinal cord injury (SCI) in rat model possibly via its anti-apoptotic activity in the nervous system. This study investigated the molecular mechanism of its anti-apoptotic and neuroprotective effects in N2a neuroblastoma cells and in rat SCI model. GM-CSF inhibited staurosporine-induced cytotoxicity and apoptosis of N2a cells. Single administration of GM-CSF either intraperitoneally or locally using a gelfoam, clearly reduced the apoptotic events in the surrounding region of the injury site in rat SCI model. Immunohistochemical analysis showed that apoptosis of cells occurred mainly in the neurons, but not significantly in the astrocytes in the surrounding regions. In both N2a cells and in rat SCI model, GM-CSF actually reduced the expression of pro-apoptotic proteins (p53, p21(WAF1/CIP1) and Bax), while further induced that of an anti-apoptotic protein (Bcl-2). In the Basso-Beattie-Bresnahan (BBB) locomotor test, the single GM-CSF administration showed better behavioral recovery than the untreated control only at early times within 1 week after injury. Overall, GM-CSF was shown to exert its neuroprotective effect on the neural injury by regulating the expression of apoptosis related genes, providing the molecular basis on its anti-apoptotic activity. Longer administration of GM-CSF appeared to be necessary for the sustained functional recovery from SCI.
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PMID:GM-CSF inhibits apoptosis of neural cells via regulating the expression of apoptosis-related proteins. 1733 4

Aberrant cytoplasmic sequestration has been reported as an alternative mechanism of p53 inactivation to mutation in neuroblastoma. We hypothesized that p53 localization and function in neuroblastoma is related to differentiation status. Eighty-two untreated and 24 paired pre and post-chemotherapy neuroblastomas were studied by immunocytochemistry for p53, p21(WAF1), BAX, Bcl2 and Ki67. Predominantly nuclear p53 was detected in undifferentiated neuroblastoma, and both nuclear and cytoplasmic p53 in differentiating neuroblastoma. The nuclear p53 labeling index (LI) correlated with the Ki67 LI (r = 0.51, p <0.001), and weakly with p21(WAF1) (r = 0.37), but not with BAX or Bcl2. There was a significant reduction in p53, p21(WAF1) and Ki67 LI after chemotherapy (p < 0.01), an increase in BAX (p <0.05), but no change in Bcl2. p53 localization and function were examined in two p53 wild-type undifferentiated and 9-cis retinoic acid differentiated neuroblastoma cell lines. Using immunocytochemistry, immunofluorescence and cell fractionation, p53 was found to be predominantly nuclear in both undifferentiated and differentiated cells. Following irradiation, there was upregulation of p53, p21(WAF1) and MDM2, but less induced PARP and caspase 3 cleavage in differentiated cells, suggesting intact p53 transcriptional function, but resistance to apoptosis. p53 function in undifferentiated and differentiated cells was confirmed by upregulation of p21(WAF1) and MDM2 following Nutlin-3 treatment. In conclusion, p53 is predominantly nuclear and functional in neuroblastoma regardless of differentiation status.
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PMID:p53 is nuclear and functional in both undifferentiated and differentiated neuroblastoma. 1791 39

The aim of the present study was to assess whether exposure to a sinusoidal extremely low frequency magnetic field (ELF-MF; 50 Hz, 1 mT) can affect proliferation and differentiation in the human neuroblastoma cell line BE(2)C, which is representative of high risk neuroblastomas. Cells were subjected to ELF-MF exposure in the presence or absence of a neuronal differentiating agent (all-trans-retinoic acid, ATRA) for 24-72 h. In each experiment, ELF-MF-exposed samples were compared to sham-exposed samples. Cells exposed to ELF-MF combined with retinoic treatment showed a decreased cellular proliferation and an increased proportion of G(0)/G(1) phase cells compared to cells exposed to either treatment alone. Moreover, ELF-MF- and ATRA-treated cells showed more differentiated morphological traits (a higher neurite number/cell, an increased neurite length), together with a significant increase of mRNA levels of p21(WAF1/CIP1) and cdk5 genes, both involved in neuronal differentiation. In addition, the expression of cyp19 gene, which is involved both in neuronal differentiation and stress response, was evaluated; cyp19 gene expression was enhanced by ATRA treatment and significantly enhanced further by ELF-MF exposure combined with ATRA. In conclusion, our data suggest that ELF-MF exposure can strengthen ATRA effects on neuroblastoma cells.
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PMID:Synergic effect of retinoic acid and extremely low frequency magnetic field exposure on human neuroblastoma cell line BE(2)C. 2056 73

Antitumor effects of erythromycin and the related mechanism were investigated in the present study. Neuroblastoma cells (SH-SY5Y) were exposed to erythromycin at different concentrations for different durations. Cell proliferation was measured by cell counting, and cell viability was examined by MTT assay. Cell cycle phase distribution and the cytosolic calcium level were detected by flow cytometry. Mitochondrial membrane potential was measured by the JC-1 probe staining and fluorescent microscopy. The expression of an oncogene (c-Myc) and a tumor suppressor [p21 (WAF1/Cip1)] proteins was analyzed by using Western blotting. Erythromycin could inhibit the proliferation of SH-SY5Y cells in a concentration- and time-dependent manner. The cell cycle was arrested at S phase. Mitochondrial membrane potential collapsed and the cytosolic calcium was overloaded in SH-SY5Y cells when treated with erythromycin. The expression of c-Myc protein was down-regulated, while that of p21 (WAF1/Cip1) protein was up-regulated. It was concluded that erythromycin could restrain the proliferation of SH-SY5Y cells. The antitumor mechanism of erythromycin might involve regulating the expression of c-Myc and p21 (WAF1/Cip1) proteins.
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PMID:Antitumor activity of erythromycin on human neuroblastoma cell line (SH-SY5Y). 2133 20


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