Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ardipusilloside III is a saponin newly isolated from Ardisia pusilla A.DC. Since saponins have exhibited broad anti-cancer and pro-apoptotic activity, we investigated the ability of ardipusilloside III to induce apoptosis in human glioblastoma U251MG cells, as well as the involvement of apoptotic signaling pathways. Ardipusilloside III markedly suppressed proliferation of U251MG cells in a time- and dose-dependent manner (P < 0.05, IC50 = 8.2 microg/ml), but did not affect the growth of primary cultures of human astrocytes. Ardipusilloside III-treated U251MG cells underwent typical apoptotic changes. Exposure to a low dose of ardipusilloside III provoked G2/M-phase cell cycle arrest, which preceded apoptosis characterized by the appearance of cells with sub-G1 DNA content. However, a higher dose of ardipusilloside III induced apoptosis without first causing cell cycle arrest. In addition, ardipusilloside III exposure resulted in time-dependent BAD dephosphorylation and cleavage as well as activation of caspase-8 and caspase-3. Therefore, both the intrinsic pathway of apoptosis, mediated by BAD dephosphorylation and cleavage, and the extrinisic pathway of apoptosis, mediated by caspase-8 and caspase-3 activation, were involved in ardipusilloside III-induced apoptosis. These data suggest that ardipusilloside III is a reliable candidate for chemotherapeutic treatment of human glioblastomas, and should be investigated further.
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PMID:Apoptosis induced by ardipusilloside III through BAD dephosphorylation and cleavage in human glioblastoma U251MG cells. 1818 Oct 22

Glioblastoma is the deadliest brain tumor that remains incurable. We examined efficacy of combination of retinoid and interferon-gamma (IFN-gamma) in human glioblastoma T98G and U87MG cells. We conjectured that retinoid could induce differentiation with down regulation of telomerase activity to increase sensitivity to IFN-gamma for apoptosis in glioblastoma cells. Indeed, treatment of cells with 1 muM all-trans retinoic acid (ATRA) or 1 muM 13-cis retinoic acid (13-CRA) for 7 days induced astrocytic differentiation with upregulation of glial fibrillary acidic protein (GFAP) and down regulation of telomerase activity. Wright staining and ApopTag assay showed, respectively, morphological and biochemical features of apoptosis in glioblastoma cells following exposure to 200 units/ml IFN-gamma for 48 h. Induction of differentiation was associated with decreases in levels of nuclear factor kappa B (NFkappaB), inducible nitric oxide synthase (iNOS), and production of nitric oxide (NO) so as to increase sensitivity to IFN-gamma for apoptosis. Notably, IFN-gamma induced signal transducer and activator of transcription-1 (STAT-1) to bind to gamma-activated sequence (GAS) of the target gene. Also, IFN-gamma activated caspase-8 and cleaved Bid to truncated Bid (tBid) for translocation to mitochondria. Fura-2 assay showed increases in intracellular free [Ca2+] and activation of calpain in apoptotic cells. Besides, increases in Bax:Bcl-2 ratio and mitochondrial release of cytochrome c and Smac into the cytosol activated caspase-9 and caspase-3 for apoptosis. Taken together, our results showed that retinoid induced astrocytic differentiation with down regulation of telomerase activity and enhanced sensitivity to IFN-gamma for increasing apoptosis in human glioblastoma cells.
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PMID:Molecular mechanisms of the combination of retinoid and interferon-gamma for inducing differentiation and increasing apoptosis in human glioblastoma T98G and U87MG cells. 1836 85

Tetrazolium violet (TV), a tetrazolium salt, has been applied in several fields, including estimating respiration rate, as a redox indicator of microbial growth, and for estimating the number of viable animal cells. It has recently been found that TV is capable of inducing apoptosis in rat glioblastoma cells by way of an elusive mechanism. In this study, we demonstrated that TV also induced apoptosis in mouse breast tumor C127 cells as evidenced by nucleus condensation and nucleus fragmentation. Our data showed that TV caused activation of caspase-3 and caspase-8, but not caspase-9. An enhancement in Fas and its two ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), might be responsible for the apoptotic effect induced by TV. Also, the results first reported that TV not only inhibited C127 cells proliferation but also blocked cell cycle progression in the G1 and G2 phase, determined by MTT assay and flow cytometry analysis. Immunofluorescence assay demonstrated that TV significantly increased the expression of p53 protein, which caused cell cycle arrest. Taken together, p53, Fas/FasL, and the caspase apoptotic system may participate in the antiproliferative activity of TV in C127 cells.
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PMID:Tetrazolium violet inhibits cell growth and induces cell death in C127 mouse breast tumor cells. 1854 55

N-(4-Hydroxyphenyl) retinamide (4-HPR) is a synthetic retinoid that has shown biological activity against several malignant tumors and minimal side effects in humans. To explore the mechanisms underlying the chemotherapeutic effects of 4-HPR in glioblastoma, we used two human glioblastoma T98G and U87MG cell lines. In situ methylene blue staining showed the morphological features of astrocytic differentiation in glioblastoma cells following exposure to 1 microM and 2 microM 4-HPR for a short duration (24 h). Astrocytic differentiation was associated with an increase in expression of glial fibrillary acidic protein (GFAP) and downregulation of telomerase. Wright staining and ApopTag assay indicated appearance of apoptotic features in glioblastoma cells following exposure to 1 microM and 2 microM 4-HPR for a long duration (72 h). We found that 4-HPR caused apoptosis with activation of caspase-8 and cleavage of Bid to truncated Bid (tBid). Besides, apoptosis was associated with alterations in expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins resulting in an increase in Bax:Bcl-2 ratio, mitochondrial release of cytochrome c and Smac, downregulation of selective baculoviral inhibitor-of-apoptosis repeat containing (BIRC) molecules, an increase in intracellular free [Ca2+], and activation of calpain and caspase-3. Taken together, these results strongly suggested that 4-HPR could be used at low doses for induction of both differentiation and apoptosis in human glioblastoma cells.
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PMID:N-(4-Hydroxyphenyl) retinamide induced both differentiation and apoptosis in human glioblastoma T98G and U87MG cells. 1860 1

Resistance to tumor necrosis factor (TNFalpha)-induced apoptosis in various cancer cells has been attributed to the activation of the transcription factor NF-kappaB. Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]one)-a selenoorganic compound is known to prevent TNFalpha-mediated NF-kappaB activity. As glioblastoma are resistant to the cytotoxic effect of TNFalpha, we investigated the potential of Ebselen in sensitizing glioma cells to TNFalpha-induced apoptosis. Although treatment with Ebselen reduced viability of glioma cells, cotreatment with TNFalpha enhanced apoptosis further through alteration of TNFalpha-mediated signaling pathways. Sensitization of TNFalpha activated glioma cells to apoptosis by Ebselen involved 2 pathways: (i) abrogation of TNFalpha induced NF-kappaB activation and (ii) induction of Fas-associated death inducing signaling complex (DISC) formation. Ebselen inhibited the prosurvival pathway mediated by NF-kappaB by altering the association of TNF receptor associated factor 2 (TRAF2) with TNFalpha receptor associated death domain (TRADD) in the TNFR1-TRADD-TRAF2 complex -an interaction crucial for mediating NF-kappaB activity. Ebselen also induced the formation of DISC involving Fas, Fas-associated death domain (FADD) and active caspase 8 to transduce apoptotic signals in situations where NF-kappaB function was inhibited. Cotreatment with Ebselen and TNFalpha induced G2/M phase arrest in cell cycle and modulated the expression of molecules involved in cell cycle progression. These results raise the possibility of overcoming resistance to TNFalpha-induced apoptosis by cotreatment with organoselenium Ebselen as a strategy to kill glioma cells.
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PMID:Ebselen sensitizes glioblastoma cells to Tumor Necrosis Factor (TNFalpha)-induced apoptosis through two distinct pathways involving NF-kappaB downregulation and Fas-mediated formation of death inducing signaling complex. 1870 44

The cytotoxic activity of sodium 5,6-benzylidene-L-ascorbate (SBA) against eight human cancer cell lines and three human normal cells was investigated, SBA showed slightly higher cytotoxicity against human tumor cell lines, as compared with normal cells, with a tumor-specificity index of 2.0. The human myelogenous leukemia cell lines (HL-60, ML-1, KG-1) were the most sensitive to SBA, followed by human oral squamous cell carcinoma (HSC-2, HSC-3, HSC-4) and human glioblastoma (T98G, U87MG). Human oral normal cells (gingival fibroblast, pulp cell, periodontal ligament fibroblast) were the most resistant. In contrast to actinomycin D, SBA induced little or no activation of caspase-3, caspase-8 and caspase-9 in the HSC-2, HSC-4, T98G and HL-60 cells, regardless of incubation time (either 6 or 24 h). SBA induced little or no internucleosomal DNA fragmentation after 6 h in all of these cells. However, prolonged treatment with SBA (24 h) induced a smear pattern of DNA fragmentation in the HSC-2, HSC-4 and T98G cells and a low level of internucleosomal DNA fragmentation in the HL-60 cells. Electron microscopy demonstrated the destruction of mitochondrial structure and autophagocytosis of broken organelles by SBA in the HSC-2, HSC-4 and HL-60 cells. At higher concentrations of SBA, necrotic cell death was observed in the HSC-2 cells, but not in the T98G cells, where the production of acidic organelles (detected by acridine orange staining) was much lower than that attained by nutritional starvation, a well-defined method of inducing autophagy. The present study suggests that SBA induces various degrees of autophagic cell death, followed by either necrosis or apoptosis at laters stage, depending on the cell type.
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PMID:Tumor-specific cytotoxicity and type of cell death induced by sodium 5,6-benzylidene-L-ascorbate. 1903 81

Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/Apo2L) is a promising cancer drug. However, many tumours are resistant to TRAIL-based therapies. Glioma cells with stem cell features (SCG), such as CD133 expression and neurosphere formation, have been recently identified to be more resistant to cytotoxic drugs than glioma cells lacking stem-cell-like features (NSCGs). Here we report that SCGs are completely resistant to 100-2,000 ng/ml TRAIL, whereas NSCGs revealed a moderate sensitivity to TRAIL. We found that SCGs exhibited only low levels of caspase-8 mRNA and protein, known to be indispensable for TRAIL-induced apoptosis. In addition, we detected hypermethylation of CASP8 promoter in SCGs, whereas NSCGs exhibited a non-methylated CASP8 promoter. Reexpression of caspase-8 by 5-Aza-2'-deoxycytidine was not sufficient to restore TRAIL sensitivity in SCGs cells, suggesting that additional factors cause TRAIL resistance in SCGs. Our data suggest that therapy with TRAIL, either as monotherapy or in combination with demethylating agents, is not effective in treating glioblastoma because SCGs are not targeted by such treatment.
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PMID:Stem-cell-like glioma cells are resistant to TRAIL/Apo2L and exhibit down-regulation of caspase-8 by promoter methylation. 1921 42

Glioblastoma grows aggressively due to its ability to maintain abnormally high potentials for cell proliferation. The present study examines the synergistic actions of N-(4-hydroxyphenyl) retinamide (4-HPR) and paclitaxel (PTX) to control the growth of rat glioblastoma C6 and RG2 cell lines. 4-HPR induced astrocytic differentiation that was accompanied by increased expression of the tight junction protein e-cadherin and sustained down regulation of Id2 (member of inhibitor of differentiation family), catalytic subunit of rat telomerase reverse transcriptase (rTERT), and proliferating cell nuclear antigen (PCNA). Flow cytometric analysis showed that the microtubule stabilizer PTX caused cell cycle deregulation due to G2/M arrest. This in turn could alter the fate of kinetochore-spindle tube dynamics thereby halting cell cycle progression. An interesting observation was the induction of G1/S arrest by a combination of 4-HPR and PTX, altering the G2/M arrest induced by PTX alone. This was further ratified by the upregulation of tumor suppressor protein retinoblastoma, which repressed the expression of the key signaling moieties to induce G1/S arrest. Collectively, the combination of 4-HPR and PTX diminished the survival factors (e.g., rTERT, PCNA, and Bcl-2) to make glioblastoma cells highly prone to apoptosis with activation of cysteine proteases (e.g., calpain, cathepsins, caspase-8, caspase-3). Hence, the combination of 4-HPR and PTX can be considered as an effective therapeutic strategy for controlling the growth of heterogeneous glioblastoma cell populations.
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PMID:N-(4-Hydroxyphenyl) retinamide potentiated paclitaxel for cell cycle arrest and apoptosis in glioblastoma C6 and RG2 cells. 1928 47

To explore the molecular mechanisms by which glioblastomas are resistant to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), we examined TRAIL signalling pathways in the tumours. TRAIL has four membrane-anchored receptors, death receptor 4/5 (DR4/5) and decoy receptor 1/2 (DcR1/2). Of these receptors, only DR5 was expressed consistently in glioblastoma cell lines and tumour tissues, ruling out the role of DcR1/2 in TRAIL resistance. Upon TRAIL binding, DR5 was homotrimerized and recruited Fas-associated death domain (FADD) and caspase-8 for the assembly of death-inducing signalling complex (DISC) in the lipid rafts of the plasma membrane. In the DISC, caspase-8 was cleaved and initiated apoptosis by cleaving downstream caspases in TRAIL-sensitive glioblastoma cells. In TRAIL-resistant cells, however, DR5-mediated DISC was modified by receptor-interacting protein (RIP), cellular FADD-like interleukin-1beta-converting enzyme inhibitory protein (c-FLIP) and phosphoprotein enriched in diabetes or in astrocyte-15 (PED/PEA-15). This DISC modification occurred in the non-raft fractions of the plasma membrane and resulted in the inhibition of caspase-8 cleavage and activation of nuclear factor-kappaB (NF-kappaB). Treatment of resistant cells with parthenolide, an inhibitor of inhibitor of kappaB (I-kappaB), eliminated TRAIL-induced NF-kappaB activity but not TRAIL resistance. In contrast, however, targeting of RIP, c-FLIP or PED/PEA-15 with small interfering RNA (siRNA) led to the redistribution of the DISC from non-rafts to lipid rafts and eliminated the inhibition of caspase-8 cleavage and thereby TRAIL resistance. Taken together, this study indicates that the DISC modification by RIP, c-FLIP and PED/PEA-15 is the most upstream event in TRAIL resistance in glioblastomas.
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PMID:DR5-mediated DISC controls caspase-8 cleavage and initiation of apoptosis in human glioblastomas. 1943 16

NF-kappaB activity is tightly regulated by IkappaB class of proteins. IkappaB proteins possess ankyrin repeats for binding to and inhibiting NF-kappaB. The regulatory protein, NPR1 from Brassica juncea possesses ankyrin repeats with sequence similarity to IkappaBalpha subgroup. Therefore, we examined whether stably expressed BjNPR1 could function as IkappaB in inhibiting NF-kappaB in human glioblastoma cell lines. We observed that BjNPR1 bound to NF-kappaB and inhibited its nuclear translocation. Further, BjNPR1 expression down-regulated the NF-kappaB target genes iNOS, Cox-2, c-Myc and cyclin D1 and reduced the proliferation rate of U373 cells. Finally, BjNPR1 decreased the levels of pERK, pJNK and PKCalpha and increased the Caspase-3 and Caspase-8 activities. These results suggested that inhibition of NF-kappaB activation by BjNPR1 can be a promising therapy in NF-kappaB dependent pathologies.
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PMID:Mustard NPR1, a mammalian IkappaB homologue inhibits NF-kappaB activation in human GBM cell lines. 1976 95


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