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)

Glioblastoma is the most common astrocytic brain tumor in humans. Current therapies for this malignancy are mostly ineffective. Photodynamic therapy (PDT), an exciting treatment strategy based on activation of a photosensitizer, has not yet been extensively explored for treating glioblastoma. We used 5-aminolevulinic acid (5-ALA) as a photosensitizer for PDT to induce apoptosis in human malignant glioblastoma U87MG cells and to understand the underlying molecular mechanisms. Trypan blue dye exclusion test showed a decrease in cell viability after exposure to increasing doses of 5-ALA for 4h followed by PDT with a broad spectrum blue light (400-550 nm) at a dose of 18J/cm(2) for 1h and then incubation at 37 degrees C for 4h. Following 0.5 and 1mM 5-ALA-based PDT (5-ALA-PDT), Wright staining and ApopTag assay showed occurrence of apoptosis morphologically and biochemically, respectively. After 5-ALA-PDT, down regulation of nuclear factor kappa B (NFkappaB) and baculovirus inhibitor-of-apoptosis repeat containing-3 (BIRC-3) protein indicated inhibition of survival signals. Besides, 5-ALA-PDT caused increase in Bax:Bcl-2 ratio and mitochondrial release of cytochrome c and apoptosis-inducing factor (AIF). Activation of calpain, caspase-9, and caspase-3 occurred in course of apoptosis. Calpain and caspase-3 activities cleaved alpha-spectrin at specific sites generating 145kD spectrin breakdown product (SBDP) and 120kD SBDP, respectively. The results suggested that 5-ALA-PDT induced apoptosis in U87MG cells by suppression of survival signals and activation of proteolytic pathways. Thus, 5-ALA-PDT can be an effective strategy for inducing apoptosis in glioblastoma.
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PMID:5-Aminolevulinic acid-based photodynamic therapy suppressed survival factors and activated proteases for apoptosis in human glioblastoma U87MG cells. 1733 70

Glioblastoma is the most malignant human brain tumor that shows poor response to existing therapeutic agents. Search continues for an effective therapy for controlling this deadliest brain tumor. Curcumin (CCM), a polyphenolic compound from Curcuma longa, possesses anti-cancer properties in both in vitro and in vivo. In the present investigation, we evaluated the therapeutic efficacy of CCM against human malignant glioblastoma U87MG cells. Trypan blue dye exclusion test showed decreased viability of U87MG cells with increasing dose of CCM. Wright staining and ApopTag assay, respectively, showed the morphological and biochemical features of apoptosis in U87MG cells treated with 25 microM and 50 microM of CCM for 24 h. Western blotting showed activation of caspase-8, cleavage of Bid to tBid, increase in Bax:Bcl-2 ratio, and release of cytochrome c from mitochondria followed by activation of caspase-9 and caspase-3 for apoptosis. Also, CCM treatments increased cytosolic level of Smac/Diablo to suppress the inhibitor-of-apoptosis proteins and down regulated anti-apoptotic nuclear factor kappa B (NFkappaB), favoring the apoptosis. Increased activities of calpain and caspase-3 cleaved 270 kDa alpha-spectrin at specific sites generating 145 kDa spectrin break down product (SBDP) and 120 kDa SBDP, respectively, leading to apoptosis in U87MG cells. Results show that CCM is an effective therapeutic agent for suppression of anti-apoptotic factors and activation of calpain and caspase proteolytic cascades for apoptosis in human malignant glioblastoma cells.
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PMID:Curcumin suppressed anti-apoptotic signals and activated cysteine proteases for apoptosis in human malignant glioblastoma U87MG cells. 1756 68

Glioblastoma is the deadliest brain tumor in humans. Current therapies are mostly ineffective and new agents need to be explored for controlling this devastating disease. Inositol hexaphosphate (IP6) is a phytochemical that is widely found in corns, cereals, nuts, and high fiber-content foods. Previous studies demonstrated anti-cancer properties of IP6 in several in vitro and in vivo tumor models. However, therapeutic efficacy of IP6 has not yet been evaluated in glioblastoma. Here, we explored the molecular mechanism of action of IP6 in human malignant glioblastoma T98G cells. The viability of T98G cells decreased following treatment with increasing doses of IP6. T98G cells exposed to 0.25, 0.5, and 1 mM IP6 for 24 h showed morphological and biochemical features of apoptosis. Western blotting indicated changes in expression of Bax and Bcl-2 proteins resulting in an increase in Bax:Bcl-2 ratio and upregulation of cytosolic levels of cytochrome c and Smac/Diablo, suggesting involvement of mitochondria-dependent caspase cascade in apoptosis. IP6 downregulated cell survival factors such as baculovirus inhibitor-of-apoptosis repeat containing-2 (BIRC-2) protein and telomerase to promote apoptosis. Upregulation of calpain and caspase-9 occurred in course of apoptosis. Increased activities of calpain and caspase-3 cleaved 270 kD alpha-spectrin at specific sites generating 145 kD spectrin break down product (SBDP) and 120 kD SBDP, respectively. Increased caspase-3 activity also cleaved inhibitor of caspase-3-activated DNase and poly(ADP-ribose) polymerase. Collectively, our results demonstrated that IP6 down regulated the survival factors BIRC-2 and telomerase and upregulated calpain and caspase-3 activities for apoptosis in T98G cells.
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PMID:Molecular mechanism of inositol hexaphosphate-mediated apoptosis in human malignant glioblastoma T98G cells. 1761 15

Glioblastoma is the deadliest and most prevalent brain tumor, which is not yet amenable to any treatments. Therefore, new and innovative therapeutic strategies need to be developed for treating this deadly disease. We found that all-trans retinoic acid (ATRA) or 13-cis retinoic acid (13-CRA) induced astrocytic differentiation with down regulation of telomerase activity in rat glioblastoma C6 cells and enhanced sensitivity of the cells to interferon-gamma (IFN-gamma) or taxol (TXL) for apoptosis. Sensitivity of differentiated cells to IFN-gamma or TXL was greatly increased for apoptosis with increases in calcineurin expression, Bax:Bcl-2 ratio, mitochondrial release of cytochrome c, and expression and activity of calpain and caspases. Treatment with IFN-gamma activated caspase-8 indicating induction of apoptosis via the receptor-mediated pathway. Notably, IFN-gamma activated the signal transducer and activator of transcription-1 (STAT-1) for signaling via binding to gamma activator sequence (GAS), whereas TXL activated Raf-1 kinase for inactivation of Bcl-2 by its phosphorylation. We confirmed involvement of different proteolytic mechanisms in cell death by pretreating the cells with caspase-8 inhibitor II, calpeptin (calpain inhibitor), and caspase-9 inhibitor I, and caspase-3 inhibitor IV. Results demonstrated that retinoids induced astrocytic differentiation with down regulation of telomerase activity and worked synergistically to enhance sensitivity of cells to the cytotoxic agent IFN-gamma and the cytostatic agent TXL for apoptosis. This combination therapy for differentiation and apoptosis could be highly effective for controlling the malignant growth of glioblastoma.
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PMID:Differentiation decreased telomerase activity in rat glioblastoma C6 cells and increased sensitivity to IFN-gamma and taxol for apoptosis. 1769 33

Glioblastoma is the most prevalent and highly malignant brain tumor that continues to defy current treatment strategies. This investigation used all-trans retinoic acid (ATRA) and taxol (TXL) as a combination therapy for controlling the growth of human glioblastoma T98G xenografted in athymic nude mice. Histopathological examination revealed that ATRA induced differentiation and combination of ATRA and TXL caused more apoptosis than either treatment alone. Combination therapy decreased expression of telomerase, nuclear factor kappa B (NFkappacapital VE, Cyrillic), and inhibitor-of-apoptosis proteins (IAPs) indicating suppression of survival factors while upregulated Smac/Diablo. Combination therapy also changed expression of Bax and Bcl-2 proteins leading to increased Bax:Bcl-2 ratio, mitochondrial release of cytochrome c and apoptosis-inducing factor (AIF), and activation of caspase-9. Increased activities of calpain and caspase-3 degraded 270 kD alpha-spectrin at the specific sites to generate 145 kD spectrin breakdown product (SBDP) and 120 kD SBDP, respectively. Further, increased activity of caspase-3 cleaved inhibitor-of-caspase-activated DNase (ICAD). In situ double immunofluorescent labelings showed overexpression of calpain, caspase-12, caspase-3, and AIF during apoptosis, suggesting involvement of both caspase-dependent and caspase-independent pathways for apoptosis. Our investigation revealed that treatment of glioblastoma T98G xenografts with the combination of ATRA and TXL induced differentiation and multiple molecular mechanisms for apoptosis.
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PMID:Combination of all-trans retinoic acid and taxol regressed glioblastoma T98G xenografts in nude mice. 1770 58

We hypothesized that induction of differentiation with retinoid could increase sensitivity to microtubule-binding drug taxol (TXL) for apoptosis in human glioblastoma T98G and U87MG cells. Treatment of cells with 1 microM all-trans retinoic acid (ATRA) or 1 microM 13-cis retinoic acid (13-CRA) for 7 days induced astrocytic differentiation, overexpression of glial fibrillary acidic protein (GFAP), and also down regulated telomerase expression and activity, thereby increased sensitivity to TXL for apoptosis. Treatment of glioblastoma cells with TXL triggered production of reactive oxygen species (ROS), induced phosphorylation of p38 mitogen-activated protein kinase (MAPK), and activated the redox-sensitive c-Jun NH(2)-terminal kinase 1 (JNK1) pathway. Moreover, TXL activated Raf-1 kinase for phosphorylation and inactivation of anti-apoptotic Bcl-2 protein. The events of apoptosis included increase in expression of Bax, down regulation of Bcl-2 and baculoviral inhibitor-of-apoptosis protein (IAP) repeat containing (BIRC) proteins, mitochondrial release of cytochrome c and Smac into the cytosol, increase in intracellular free [Ca(2+)], and activation of calpain, caspase-9, and caspase-3. Increased activity of caspase-3 cleaved inhibitor of caspase-activated DNase (ICAD) to release and translocate CAD to the nucleus for DNA fragmentation. Involvement of stress signaling kinases and proteolytic activities of calpain and caspase-3 in apoptosis was confirmed by pretreating cells with specific inhibitors. Taken together, our results suggested that retinoid (ATRA or 13-CRA) induced astrocytic differentiation with down regulation of telomerase activity to increase sensitivity to TXL to enhance apoptosis in glioblastoma cells. Thus, combination of retinoid and TXL could be an effective therapeutic strategy for controlling the growth of glioblastoma.
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PMID:Retinoids induced astrocytic differentiation with down regulation of telomerase activity and enhanced sensitivity to taxol for apoptosis in human glioblastoma T98G and U87MG cells. 1798 64

Gambogic acid (GA) is the major active ingredient of gamboge, a brownish to orange resin exuded from Garcinia hanburryi tree in Southeast Asia. The present study aims to demonstrate that gambogic acid (GA) has potent anticancer activity for glioblastoma by in vitro and in vivo study. Rat brain microvascular endothelial cells (rBMEC) were used as an in vitro model of the blood-brain barrier (BBB). To reveal an involvement of the intrinsic mitochondrial pathway of apoptosis, the mitochondrial membrane potential and the western blot evaluation of Bax, Bcl-2, Caspase-3, caspase-9 and cytochrome c released from mitochondria were performed. Angiogenesis was detected by CD31 immunochemical study. The results showed that the uptake of GA by rBMEC was time-dependent, which indicated that it could pass BBB and represent a possible new target in glioma therapy. GA could cause apoptosis of rat C6 glioma cells in vitro in a concentration-dependent manner by triggering the intrinsic mitochondrial pathway of apoptosis. In vivo study also revealed that i.v. injection of GA once a day for two weeks could significantly reduce tumor volumes by antiangiogenesis and apoptotic induction of glioma cells. Collectively, the current data indicated that GA may be of potential use in treatment of glioblastoma by apoptotic induction and antiangiogenic effects.
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PMID:Inhibition of glioblastoma growth and angiogenesis by gambogic acid: an in vitro and in vivo study. 1807 Jun 17

Glioblastoma is the most malignant and prevalent brain tumor in humans. It is composed of heterogenic abnormal astroglial cells that avoid differentiation, maintain proliferation, and hardly commit apoptosis. N-(4-Hydroxyphenyl)retinamide (4-HPR) induced astrocytic differentiation and increased sensitivity to interferon-gamma (IFN-gamma) for apoptosis in human glioblastoma A172, LN18, and SNB19 cells. Combination of 4-HPR and IFN-gamma significantly inhibited human telomerase reverse transcriptase (hTERT), cyclin dependent kinase 2 (CDK2), and survivin to up-regulate caspase-8, caspase-9, and caspase-3 for increasing apoptosis in all glioblastoma cell lines. Hence, combination of 4-HPR and IFN-gamma should be considered for controlling growth of different human glioblastoma cells.
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PMID:N-(4-Hydroxyphenyl)retinamide induced differentiation with repression of telomerase and cell cycle to increase interferon-gamma sensitivity for apoptosis in human glioblastoma cells. 1816 43

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

Melanoma differentiation associated gene-7/interleukin 24 (mda-7/IL-24) is a cytokine displaying selective apoptosis-inducing activity in tumors, including glioblastoma (GBM), without damaging normal cells. The present studies focused on defining whether an adenovirus expressing MDA-7/IL-24, Ad.mda-7, infused into pre-formed invasive primary human GBM tumors growing in athymic mouse brains altered tumor cell growth and animal survival, and whether Ad.mda-7 radiosensitized GBM cells and enhanced the survival benefit of irradiation. Ad.mda-7 directly radiosensitized glioma cells in vitro in a JNK1-3- and caspase 9-dependent fashion and demonstrated bystander-effect killing and radiosensitization of GBM cells when primary human astrocytes were infected with Ad.mda-7. Infusion of Ad.mda-7 into pre-formed glioma tumors caused a rapid decrease in proliferation and blood vessel density and an increase in cell killing. Irradiation of Ad.mda-7 infected tumors enhanced cell death. Cell killing correlated with pro-caspase 3 cleavage, enhanced phosphorylation of JNK1-3 and reduced phosphorylation of ERK1/2. Ad.mda-7 enhanced the survival of animals implanted with GBM6 and GBM12 tumors, and significantly increased the survival benefit of irradiation in animals bearing GBM12 tumors. Ad.mda-7 toxicity was evident against CD133+ and CD133- GBM cells; upon tumor re-growth approximately 70-100 days after virus infusion, the relative CD133+ level within the tumor was profoundly reduced with lower Ki67 reactivity and increased beta-galactosidase staining. Infusion of Ad.mda-7 into an immune competent rat brain did not cause normal tissue toxicity 1-4 weeks after infusion using T1 and T2 weighted MRI and H&E staining. Our data demonstrate that Ad.mda-7 prolongs the survival of animals bearing GBM tumors and does so through multiple mechanisms including direct tumor cell killing and selection for surviving cells that are more differentiated and potentially displaying a putatively senescent phenotype.
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PMID:MDA-7/IL-24 plus radiation enhance survival in animals with intracranial primary human GBM tumors. 1837 44


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