GBM response to Smo and PI3K inhibitors
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Rosalind Segal
PROVIDER: E-GEOD-49416 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Combination therapy with Smo and PI3K inhibitors results in a synergistic effect in reducing tumor growth in PTEN-deficient Glioblastoma. To identify consequences of combination therapy with an Smo inhibitor and a PI3K inhibitor on a genome-wide scale, we performed Affymetrix microarrays with two different PTEN-deficient GBMs treated with single drugs or combination therapy. A small set of genes was significantly affected by combination therapy in hBT70 and/or hBT112, including several genes implicated in GBM prognosis, or identified as targets of Shh, PI3K or S6 pathways 29-33 .
2013-09-01 | GSE49416 | GEO
Project description:Activation of the PI3K pathway in estrogen receptor α (ER)-positive (+) breast cancer is associated with reduced ER expression and activity, luminal B subtype, and poor outcome. PTEN is a negative regulator of the PI3K pathway typically lost in ER-negative (-) breast cancer. To clarify the effect of PTEN down-regulation on the response of ER+/HER2- breast cancer to endocrine therapy, we established reduced PTEN cell models using inducible knockdown. We found that only moderate PTEN reduction is sufficient to enhance PI3K signaling, generate a gene signature associated with luminal B subtype, and cause endocrine resistance. Combining endocrine therapy with mTOR, AKT, or MEK inhibitors improves antitumor activity, but the efficacy varies by type of endocrine therapy and the specific inhibitor. Fulvestrant plus an AKT inhibitor is the most potent combination when PTEN is reduced, inducing apoptosis and tumor regression. This combination deserves further study in patients with PI3K pathway activation.
2014-06-30 | GSE53300 | GEO
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma. mRNA profiling: RNA was prepared from tumours from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Affymetrix Mouse Genome 430 2.0 RNA expression array. The dosage terminology (BID & QD) reflects the dosing schedule, where BID = twice a day, QD = once a day. aCGH: DNA was prepared from tumors from vehicle or NVP-LDE225 treated nude mice allografted with medulloblastoma tumors derived from Ptch+/-p53-/- transgenic mouse and hybridized on Agilent mouse CGH 244K Array.
2010-09-29 | E-GEOD-19657 | biostudies-arrayexpress
Project description:Purpose: PTEN loss-of-function occurs in ~50% of metastatic, castrate-resistant prostate cancer (mCRPC) patients, and associated with poor prognosis and responsiveness to standard-of-care therapies and immune checkpoint inhibitors. While PTEN loss-of-function hyperactivates PI3K signaling, combinatorial PI3K/AKT pathway and androgen deprivation therapy (ADT) has demonstrated limited anti-cancer efficacy in clinical trials. Here, we aimed to elucidate mechanism(s) of resistance to ADT/PI3K-AKT axis blockade, and to develop rational combinatorial strategies to effectively treat this molecular subset of mCRPC. Experimental design: Prostate-specific PTEN/p53-deficient genetically engineered mice (GEM) with established 150-200 mm3 tumors, as assessed by ultrasound, were treated with either ADT (degarelix), PI3K inhibitor (copanlisib), or anti-PD-1 antibody (aPD-1), as single agents or their combinations, and tumors were monitored by MRI and harvested for immune, transcriptomic and proteomic profiling, or ex vivo co-culture studies. Single-cell RNAseq on human mCRPC samples was performed using 10X Genomics platform. Results: Co-clinical trials in PTEN/p53-deficient GEM revealed that recruitment of PD-1-expressing tumor-associated macrophages (TAM) thwarts ADT/PI3Ki combination-induced tumor control. The addition of aPD-1 to ADT/PI3Ki combination led to TAM-dependent ~3-fold increase in anti-cancer responses. Mechanistically, decreased lactate production from PI3Ki-treated tumor cells suppressed histone lactylation within TAM, resulting in their anti-cancer phagocytic activation, which was augmented by ADT/aPD-1 treatment and abrogated by feedback activation of Wnt/β-catenin pathway. Single-cell RNA-sequencing analysis in mCRPC patient biopsy samples revealed a direct correlation between high glycolytic activity and TAM phagocytosis suppression. Conclusions: Immunometabolic strategies that reverse lactate and PD-1-mediated TAM immunosuppression, in combination with ADT, warrant further investigation in PTEN-deficient mCRPC patients.
2023-02-21 | GSE225074 | GEO
Project description:Glioblastoma (GBM) is the most lethal brain tumour that occurs in adults and treatment for GBM has been largely unsuccessful. Ionizing radiation (IR) and chemotherapeutic agents are employed as standard of care treatment for GBM patients and both result in DNA damage. Previous data identified phosphorylation of PTEN at tyrosine 240 (pY240) in samples from patients with recurrent GBM receiving standard of care treatment and was associated with decreased overall survival. Here we demonstrate that pY240 PTEN that was triggered by FGFR2 signaling, enhanced DNA repair by facilitating the loading of PTEN onto chromatin through its interaction with KI-67 and subsequent recruitment of the DNA repair protein, RAD51, to sites of DNA damage. Thus, tumour cells with pY240 PTEN are efficient at repairing DNA damage which would be predicted to result in resistance to therapy. These findings suggest the FGFR-pY240 PTEN-DNA repair mechanism as a therapeutic target for enhancing GBM therapy.
2017-08-07 | MSV000081423 | MassIVE
Project description:Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma.
2010-09-29 | GSE19657 | GEO
Project description:Dysregulation of pre-mRNA alternative splicing (AS) is closely associated with cancers. However, the relationships between the AS and classic oncogenes/tumor suppressors are largely unknown. Here we show that the deletion of tumor suppressor PTEN alters pre-mRNA splicing in its phosphatase-independent manner, and identify262 PTEN-regulated AS events in 293T cells by RNA sequencing, which are associated with significant worse outcome of cancer patients. Based on these findings, we report that nuclear PTEN interacts with the splicing machinery, spliceosome, to regulate its assembly and pre-mRNA splicing. Especially, the exon-2b exclusion of GOLGA2 contributes to PTEN knockdown-induced tumorigenesis by promoting dramatic Golgi extension and secretion, and PTEN depletion significantly sensitizes cancer cells to secretion inhibitors, Brefeldin A and Golgicide A. Given that many cancers lack PTEN expression, our results suggest that Golgi secretion inhibitors alone or in combination with PI3K/Akt kinase inhibitors may be therapeutically useful for PTEN-deficient cancers.
2018-10-18 | PXD009681 | Pride
Project description:Glioblastoma (GBM) is the most common primary brain tumor in adults with a median survival of approximately 15 months, therefore, more effective treatment options for GBM are required. To identify new drugs targeting glioblastomas, we performed a high throughput drug screen using patient-derived neurospheres cultured to preferentially retain their glioblastoma stem cell (GSC) phenotype.
High throughput drug screening was performed on GSCs followed by a second dose response assay of the 5 identified original hits. A PI3K/mTOR dependency to a proteasome inhibitor (carfilzomib), was confirmed by gain of function and loss of function experiments. Proteasome inhibition response signatures were derived from proteomic and bioinformatic analysis. Molecular mechanism of action was determined using in vitro 3-dimensional (3D) GBM organoid models and in vivo preclinical orthotopic GBM models.
We found that GSCs were highly sensitive to proteasome inhibition due to an underlying dependency on an increased protein synthesis rate, and loss of autophagy, associated with PTEN loss and activation of the PI3K/mTOR pathway. In contrast, combinatory inhibition of autophagy and the proteasome, resulted in enhanced cytotoxicity specifically in GSCs that did express PTEN. Finally, proteasome inhibition specifically increased cell death markers in 3D glioblastoma organoids, suppressed tumor growth, and increased survival of mice orthotopically engrafted with GSCs. As perturbations of the PTEN/ PI3K axis occur in nearly 50% of GBMs, these findings suggest that a significant fraction of these tumors could be vulnerable to proteasome inhibition.
2020-12-04 | MSV000086560 | MassIVE
Project description:Abstract BACKGROUND: The basal-like breast cancer (BLBC) subtype is characterized by positive staining for basal mammary epithelial cytokeratin markers, lack of hormone receptor and HER2 expression, and poor prognosis with currently no approved molecularly-targeted therapies. The oncogenic signaling pathways driving basal-like tumorigenesis are not fully elucidated. METHODS: One hundred sixteen unselected breast tumors were subjected to integrated analysis of phosphoinositide 3-kinase (PI3K) pathway related molecular aberrations by immunohistochemistry, mutation analysis, and gene expression profiling. Incidence and relationships between molecular biomarkers were characterized. Findings for select biomarkers were validated in an independent series. Synergistic cell killing in vitro and in vivo tumor therapy was investigated in breast cancer cell lines and mouse xenograft models, respectively. RESULTS: Sixty-four % of cases had an oncogenic alteration to PIK3CA, PTEN, or INPP4B; when including upstream kinases HER2 and EGFR, 75 % of cases had one or more aberration including 97 % of estrogen receptor (ER)-negative tumors. PTEN-loss was significantly associated to stathmin and EGFR overexpression, positivity for the BLBC markers cytokeratin 5/14, and the BLBC molecular subtype by gene expression profiling, informing a potential therapeutic combination targeting these pathways in BLBC. Combination treatment of BLBC cell lines with the EGFR-inhibitor gefitinib plus the PI3K pathway inhibitor LY294002 was synergistic, and correspondingly, in an in vivo BLBC xenograft mouse model, gefitinib plus PI3K-inhibitor PWT-458 was more effective than either monotherapy and caused tumor regression. CONCLUSIONS: Our study emphasizes the importance of PI3K/PTEN pathway activity in ER-negative and basal-like breast cancer and supports the future clinical evaluation of combining EGFR and PI3K pathway inhibitors for the treatment of BLBC. Gene expression profiles were generated for 95 breast tumors using Agilent Human 44K v5 microarrays following the manufacturer protocol. Stratagene Universal Human Reference RNA was used as the common control sample.
2016-08-21 | E-GEOD-74667 | biostudies-arrayexpress