Targeting of mitochondrial Hsp90 with Gamitrinib, G-TPP, in U251 glioblastoma cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Siegelin Markus
PROVIDER: S-ECPF-GEOD-26313 | biostudies-other |
REPOSITORIES: biostudies-other
Similar Datasets
Project description:U251 gliolbastoma cells were treated with vehicle (DMSO) or G-TPP, a mitochondrial targeted version of 17-AAG. 6 hours after treatment RNA was harvested and subjected to microarray analysis on Human Gene 1.0 ST Array. We sought to determine a mitochdondrial gene response after targeting inhibition of mitochondrial chaperones, Hsp90.
2010-12-28 | E-GEOD-26313 | biostudies-arrayexpress
Project description:U251 gliolbastoma cells were treated with vehicle (DMSO) or G-TPP, a mitochondrial targeted version of 17-AAG. 6 hours after treatment RNA was harvested and subjected to microarray analysis on Human Gene 1.0 ST Array.
2010-12-28 | GSE26313 | GEO
Project description:Temozolomide (TMZ) is one of the most commonly used drugs for the clinical treatment of glioblastomas. However, it has been reported that treatment with TMZ can induce autophagy, which leads to tumor resistance and increases the survival of tumor cells. MicroRNA-30a (miR-30a) has been found to have inhibitory effects on autophagy by directly targeting beclin 1. However, the exact role of miR-30a in TMZ-treated glioblastoma cells has not been studied previously. The present study aimed to investigate whether miR-30a increased the cytotoxicity of TMZ to glioblastoma U251 cells, as well as the underlying mechanism. MTT and flow cytometry assay results showed that treatment with TMZ inhibited the proliferation of U251 cells while inducing cell apoptosis in a dose-dependent manner. Western blotting data showed that the expression levels of LC3-II and beclin 1 as well as the ratio of LC3-II to LC3-I were markedly increased in TMZ-treated U251 cells compared with the untreated control cells, indicating that treatment with TMZ induced autophagy. Moreover, reverse transcription-quantitative polymerase chain reaction data showed that treatment with TMZ led to a significant reduction in miR-30a levels in a dose-dependent manner in U251 cells. Elevation of the miR-30a level significantly inhibited TMZ-induced autophagy, demonstrated by the decreased LC3-II and beclin 1 levels and ratio of LC3-II to LC3-I, accompanied by the reduced proliferation and increased apoptosis in TMZ-treated U251 cells. Furthermore, luciferase reporter assay data indicated that beclin 1 was a direct target of miR-30a in U251 cells. In summary, this study demonstrated that miR-30a increases the chemosensitivity of glioblastoma U251 cells to temozolomide by directly targeting beclin 1 and inhibiting autophagy. Therefore, autophagy may be a promising target for the treatment of TMZ-resistant tumors.
| S-EPMC5952084 | biostudies-literature
Project description:A signalling pathway involving PLEKHG5 (guanine exchange factor) for the Ras superfamily member RAB26 to transcription factor NF-?B was discovered in autophagy. PLEKHG5 was reported in glioblastoma multiforme (GBM) and correlates with patient survival. Thus, the generation of a cellular model for understanding PLEKHG5 signalling is the study purpose. We generated a CRISPR/Cas9-mediated knockout of PLEKHG5 in U251-MG glioblastoma cells and analysed resulting changes. Next, we used a mRFP-GFP-LC3+ reporter for visualisation of autophagic defects and rescued the phenotype of PLEKHG5 wildtype via transduction of a constitutively active RAB26QL-plasmid. Effects of overexpressing RAB26 were investigated and correlated with the O6-methylguanine-DNA methyltransferase (MGMT) and cellular survival. PLEKHG5 knockout showed changes in morphology, loss of filopodia and higher population doubling times. Accumulation of autolysosomes was resulted by decreased LAMP-1 in PLEKHG5-deficient cells. Rescue of PLEKHG5-/- restored the downregulation of RhoA activity, showed faster response to tumour necrosis factor and better cellular fitness. MGMT expression was activated after RAB26 overexpression compared to non-transduced cells. Survival of PLEKHG5 knockout was rescued together with sensitivity to temozolomide by RAB26QL. This study provides new insights in the PLEKHG5/RAB26 signalling within U251-MG cells, which suggests potential therapeutic strategies in other glioma cells and further in primary GBM.
| S-EPMC7736842 | biostudies-literature
Project description:Proprotein convertase subtilisin/kexin type 9 (PCSK9), belongs to a family of proprotein convertases (PCs), encodes a neural apoptosis-regulated convertase 1. However, the precise role of PCSK9 during glioma cells apoptosis has not been reported. Therefore, we examined the effects of knockdown and overexpression of PCSK9 on apoptosis of human neuroglioma U251 cells, and investigated the underlying mechanisms of apoptosis. We found that PCSK9 regulated cells proliferation as determined by CCK-8 and Hoechst staining analysis. In addition, western blot results showed that PCSK9 siRNA promote apoptosis via activation of caspase-3 and down-regulation of the anti-apoptotic proteins, XIAP and p-Akt, while PCSK9 overexpression inhibited apoptosis. Moreover, PCSK9 siRNA improved the ratio of Bax/Bcl-2 which leads to the release of cytochrome c, while PCSK9 overexpression decreased it. Taken together, these data demonstrate that PCSK9 may regulate apoptosis through mitochondrial pathway and is expected to be a promising therapeutic strategy for the malignant glioma.
| S-EPMC4440094 | biostudies-literature
Project description:The molecular chaperone heat shock protein 90 (HSP90) facilitates the appropriate folding of various oncogenic proteins and is necessary for the survival of some cancer cells. HSP90 is therefore an attractive drug target, but the efficacy of HSP90 inhibitor may be limited by HSP90 inhibition induced feedback mechanisms. Through pooled RNA interference screens, we identified that heat shock factor 1(HSF1) is a sensitizer of HSP90 inhibitor. A striking combinational effect was observed when HSF1 knockdown plus with HSP90 inhibitors treatment in various cancer cell lines and tumor mouse models. Interestingly, HSF1 is highly expressed in hepatocellular carcinoma (HCC) patient samples and HCC is sensitive to combinational treatment, indicating a potential indication for the combinational treatment. To understand the mechanism of the combinational effect, we identified that a HSF1-target gene DEDD2 is involved in attenuating the effect of HSP90 inhibitors. Thus, the transcriptional activities of HSF1 induced by HSP90 inhibitors provide a feedback mechanism of limiting the HSP90 inhibitor's activity, and targeting HSF1 may provide a new avenue to enhance HSP90 inhibitors activity in human cancers.
| S-EPMC3757240 | biostudies-literature
Project description:The human TP53 gene is frequently mutated in tumors and cell lines. Unlike other tumor suppressors that are commonly inactivated by deletions or nonsense mutations, the majority of p53-mutations are missense point mutations that result in the expression of a full-length protein with an altered amino acid that has lost sequence specific DNA-binding. Expression of mutant p53 (mutp53) confers advantages to tumor cells and transcriptional regulation of several genes mediating the beneficial effects has been shown to play a role. However, molecular mechanisms of transcriptional regulation by mutp53 are still poorly understood. We used the glioblastoma-derived U-251 MG human cell line endogenously expressing mutp53 protein (R273H mutation) to analyze gene expression profiles on Agilent Whole Human Genome Microarray after transient and stable depletion of mutp53 expression. Gene expression data was correlated with a ChIP study on a custom tiling array to understand the contribution of endogenously expressed mutp53 to transcriptional regulation. This series of microarray experiments contains the gene expression profiles of glioblastoma-derived U-251 MG human cell lines engineered to constitutively express a p53-specific shRNA or scrambled control shRNA. To reverse the effect of mutp53 depletion, stable clones were modified by stable integration of a mutp53-R273H expression construct or empty pCDNA3 vector as a control. In addition, we performed gene expression analysis of U-251 MG cells transiently transfected with p53-specific siRNA or control siRNA (3 biological replicates each).
| S-ECPF-GEOD-35454 | biostudies-other
Project description:Although therapeutically targeting a single signaling pathway that drives tumor development and/or progression has been effective for a number of cancers, in many cases this approach has not been successful. Targeting networks of signaling pathways, instead of isolated pathways, may overcome this problem, which is probably due to the extreme heterogeneity of human tumors. However, the possibility that such networks may be spatially arranged in specialized subcellular compartments is not often considered in pathway-oriented drug discovery and may influence the design of new agents. Hsp90 is a chaperone protein that controls the folding of proteins in multiple signaling networks that drive tumor development and progression. Here, we report the synthesis and properties of Gamitrinibs, a class of small molecules designed to selectively target Hsp90 in human tumor mitochondria. Gamitrinibs were shown to accumulate in the mitochondria of human tumor cell lines and to inhibit Hsp90 activity by acting as ATPase antagonists. Unlike Hsp90 antagonists not targeted to mitochondria, Gamitrinibs exhibited a "mitochondriotoxic" mechanism of action, causing rapid tumor cell death and inhibiting the growth of xenografted human tumor cell lines in mice. Importantly, Gamitrinibs were not toxic to normal cells or tissues and did not affect Hsp90 homeostasis in cellular compartments other than mitochondria. Therefore, combinatorial drug design, whereby inhibitors of signaling networks are targeted to specific subcellular compartments, may generate effective anticancer drugs with novel mechanisms of action.
| S-EPMC2648691 | biostudies-literature
Project description:Glioblastoma is a highly aggressive brain tumor characterized by high recurrence and poor prognosis. Vitexin has shown activities against esophageal, liver, lung, colorectal, and ovarian cancers; however, there is little knowledge on the activity of vitexin against glioblastoma. This study was therefore designed with aims to examine the effects of vitexin on proliferation, invasion, and apoptosis of human U251 glioblastoma cells and explore the underlying molecular mechanisms using mRNA sequencing and molecular docking. Vitexin was found to inhibit cell proliferation, colony formation, and invasion and promote apoptosis in U251 cells. mRNA sequencing identified 499 differentially expressed genes in vitexin-treated U251 cells relative to controls, including 154 upregulated genes and 345 downregulated genes. Gene ontology (GO) term enrichment analysis revealed that the upregulated genes were most significantly enriched in intrinsic apoptotic signaling pathway and the downregulated genes were most significantly enriched in positive regulation of cell development and positive regulation of locomotion relating to biological processes, endoplasmic reticulum lumen and side of membrane relating to cellular components, and receptor ligand activity and receptor regulator activity relating to molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the upregulated genes were involved in the pathways of transcriptional misregulation in cancer and the downregulated genes were involved in FoxO and JAK/STAT signaling pathways. Western blotting assay revealed that vitexin treatment resulted in reduced p-JAK1, p-JAK3, and p-STAT3 protein expression in U251 cells relative to untreated controls, and molecular docking predicted that vitexin had docking scores of -8.8, -10.8, and -10.5 kJ/mol with STAT3, JAK1, and JAK2, respectively. The results of the present study demonstrate that vitexin inhibits the proliferation and invasion and induces the apoptosis of glioblastoma U251 cells through suppressing the JAK/STAT3 signaling pathway, and vitexin may be a promising potential agent for the chemotherapy of glioblastoma.
| S-EPMC8906934 | biostudies-literature
Project description:Glioblastoma is one of the most aggressive brain tumors, characterized by a pronounced redox imbalance, expressed in a high oxidative capacity of cancer cells due to their elevated glycolytic and mitochondrial oxidative metabolism. The assessment and modulation of the redox state of glioblastoma are crucial factors that can provide highly specific targeting and treatment. Our study describes a pharmacological strategy for targeting glioblastoma using a redox-active combination drug. The experiments were conducted in vivo on glioblastoma mice (intracranial model) and in vitro on cell lines (cancer and normal) treated with the redox cycling pair menadione/ascorbate (M/A). The following parameters were analyzed in vivo using MRI or ex vivo on tissue and blood specimens: tumor growth, survival, cerebral perfusion, cellular density, tissue redox state, expression of tumor-associated NADH oxidase (tNOX) and transforming growth factor-beta 1 (TGF-β1). Dose-dependent effects of M/A on cell viability, mitochondrial functionality, and redox homeostasis were evaluated in vitro. M/A treatment suppressed tumor growth and significantly increased survival without adverse side effects. This was accompanied by increased oxidative stress, decreased reducing capacity, and decreased cellular density in the tumor only, as well as increased cerebral perfusion and down-regulation of tNOX and TGF-β1. M/A induced selective cytotoxicity and overproduction of mitochondrial superoxide in isolated glioblastoma cells, but not in normal microglial cells. This was accompanied by a significant decrease in the over-reduced state of cancer cells and impairment of their "pro-oncogenic" functionality, assessed by dose-dependent decreases in: NADH, NAD+, succinate, glutathione, cellular reducing capacity, mitochondrial potential, steady-state ATP, and tNOX expression. The safety of M/A on normal cells was compromised by treatment with cerivastatin, a non-specific prenyltransferase inhibitor. In conclusion, M/A differentiates glioblastoma cells and tissues from normal cells and tissues by redox targeting, causing severe oxidative stress only in the tumor. The mechanism is complex and most likely involves prenylation of menadione in normal cells, but not in cancer cells, modulation of the immune response, a decrease in drug resistance, and a potential role in sensitizing glioblastoma to conventional chemotherapy.
| S-EPMC8833725 | biostudies-literature