Low-grade gliomas almost invariably progress into secondary glioblastoma (sGBM) with limited therapeutic option and poorly understood mechanism. By studying the mutational landscape of 188 sGBMs, we ...find significant enrichment of TP53 mutations, somatic hypermutation, MET-exon-14-skipping (METex14), PTPRZ1-MET (ZM) fusions, and MET amplification. Strikingly, METex14 frequently co-occurs with ZM fusion and is present in ∼14% of cases with significantly worse prognosis. Subsequent studies show that METex14 promotes glioma progression by prolonging MET activity. Furthermore, we describe a MET kinase inhibitor, PLB-1001, that demonstrates remarkable potency in selectively inhibiting MET-altered tumor cells in preclinical models. Importantly, this compound also shows blood-brain barrier permeability and is subsequently applied in a phase I clinical trial that enrolls MET-altered chemo-resistant glioma patients. Encouragingly, PLB-1001 achieves partial response in at least two advanced sGBM patients with rarely significant side effects, underscoring the clinical potential for precisely treating gliomas using this therapy.
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•Characterization of the mutational landscape of secondary glioblastoma•Clonal and subclonal METex14 promote glioma progression and mark worse prognosis•PLB-1001 is a highly selective, efficient, and BBB-permeable MET kinase inhibitor•PLB-1001 provides a safe and efficacious therapeutic approach for glioma treatment
A new MET inhibitor shows preliminary efficacy for treatment of patients with secondary glioblastoma.
Abstract
The prognostic and therapeutic relevance of molecular subtypes for the most aggressive isocitrate dehydrogenase 1/2 (
IDH
) wild-type glioblastoma (GBM) is currently limited due to high ...molecular heterogeneity of the tumors that impedes patient stratification. Here, we describe a distinct binary classification of
IDH
wild-type GBM tumors derived from a quantitative proteomic analysis of 39
IDH
wild-type GBMs as well as
IDH
mutant and low-grade glioma controls. Specifically, GBM proteomic cluster 1 (GPC1) tumors exhibit Warburg-like features, neural stem-cell markers, immune checkpoint ligands, and a poor prognostic biomarker, FKBP prolyl isomerase 9 (
FKBP9
). Meanwhile, GPC2 tumors show elevated oxidative phosphorylation-related proteins, differentiated oligodendrocyte and astrocyte markers, and a favorable prognostic biomarker, phosphoglycerate dehydrogenase (
PHGDH
). Integrating these proteomic features with the pharmacological profiles of matched patient-derived cells (PDCs) reveals that the mTORC1/2 dual inhibitor AZD2014 is cytotoxic to the poor prognostic PDCs. Our analyses will guide GBM prognosis and precision treatment strategies.
Glioblastoma (GBM) is a complex disease with extensive molecular and transcriptional heterogeneity. GBM can be subcategorized into four distinct subtypes; tumors that shift towards the mesenchymal ...phenotype upon recurrence are generally associated with treatment resistance, unfavorable prognosis, and the infiltration of pro-tumorigenic macrophages.
We explore the transcriptional regulatory networks of mesenchymal-associated tumor-associated macrophages (MA-TAMs), which drive the malignant phenotypic state of GBM, and identify macrophage receptor with collagenous structure (MARCO) as the most highly differentially expressed gene. MARCO
TAMs induce a phenotypic shift towards mesenchymal cellular state of glioma stem cells, promoting both invasive and proliferative activities, as well as therapeutic resistance to irradiation. MARCO
TAMs also significantly accelerate tumor engraftment and growth in vivo. Moreover, both MA-TAM master regulators and their target genes are significantly correlated with poor clinical outcomes and are often associated with genomic aberrations in neurofibromin 1 (NF1) and phosphoinositide 3-kinases/mammalian target of rapamycin/Akt pathway (PI3K-mTOR-AKT)-related genes. We further demonstrate the origination of MA-TAMs from peripheral blood, as well as their potential association with tumor-induced polarization states and immunosuppressive environments.
Collectively, our study characterizes the global transcriptional profile of TAMs driving mesenchymal GBM pathogenesis, providing potential therapeutic targets for improving the effectiveness of GBM immunotherapy.
The WNT (Wingless/Integrated) signaling pathway is implicated in various stages of glioblastoma, which is an aggressive brain tumor for which therapeutic options are limited. WNT has been recognized ...as a hallmark of therapeutic challenge due to its context-dependent role and critical function in healthy tissue homeostasis. In this review, we deeply scrutinize the WNT signaling pathway and its involvement in the genesis of glioblastoma as well as its acquired therapy resistance. We also provide an analysis of the WNT pathway in terms of its therapeutic importance in addition to an overview of the current targeted therapies under clinical investigation.
The Hsp90 family proteins Hsp90, Grp94, and TRAP1 are present in the cell cytoplasm, endoplasmic reticulum, and mitochondria, respectively; all play important roles in tumorigenesis by regulating ...protein homeostasis in response to stress. Thus, simultaneous inhibition of all Hsp90 paralogs is a reasonable strategy for cancer therapy. However, since the existing pan-Hsp90 inhibitor does not accumulate in mitochondria, the potential anticancer activity of pan-Hsp90 inhibition has not yet been fully examined in vivo. Analysis of The Cancer Genome Atlas database revealed that all Hsp90 paralogs were upregulated in prostate cancer. Inactivation of all Hsp90 paralogs induced mitochondrial dysfunction, increased cytosolic calcium, and activated calcineurin. Active calcineurin blocked prosurvival heat shock responses upon Hsp90 inhibition by preventing nuclear translocation of HSF1. The purine scaffold derivative DN401 inhibited all Hsp90 paralogs simultaneously and showed stronger anticancer activity than other Hsp90 inhibitors. Pan-Hsp90 inhibition increased cytotoxicity and suppressed mechanisms that protect cancer cells, suggesting that it is a feasible strategy for the development of potent anticancer drugs. The mitochondria-permeable drug DN401 is a newly identified in vivo pan-Hsp90 inhibitor with potent anticancer activity.
p97 has recently emerged as a therapeutic target for cancer due to its essential functions in protein homeostasis. CB-5083 is a first-in-class, potent and selective ATP-competitive p97 inhibitor that ...induces proteotoxic stress in cancer cells. Potential mechanisms regulating the sensitivity of cells to p97 inhibition remain poorly studied. Here, we demonstrate that Thrombospondin-1 (THBS1) is a CB-5083-upregulated gene that helps confer resistance of HCT116 cells to CB-5083. Our immunoblotting and immunofluorescence data showed that CB-5083 significantly increases the steady-state abundance of THBS1. Blockade of THBS1 induction sensitized cells to CB-5083-mediated growth inhibition. Suppression of THBS1 caused an increase of CB-5083-induced sub-G1 population and caspase 3/7 activity suggesting that its function is linked to the survival of cancer cells in response to p97 inhibition. Altogether our data provide new evidence that THBS1 is important for the susceptibility of cells to p97 inhibition.
Testing new ways to identify untapped opportunities for glioblastoma therapies remains highly significant. Amplification and overexpression of MDM2 gene is frequent in glioblastoma and disrupting the ...MDM2-p53 interaction is a promising strategy to treat the cancer. RG7112 is the first-in class inhibitor and recently discovered AMG232 is the most potent MDM2 inhibitor known to date. Here, we compared the effects of these two clinical MDM2 inhibitors in six glioblastoma cell lines and ten patient-derived glioblastoma stem cells. Targeted sequencing of the TP53, MDM2 genes and whole transcriptome analysis were conducted to verify genetic status associated with sensitivity and resistance to the drugs. Although TP53 wild-type glioblastoma cell lines are similarly sensitive to AMG232 and RG7112, we found that four TP53 wild-type out of ten patient-derived glioblastoma cells are much more sensitive to AMG232 than RG7112 (average IC
of 76 nM vs. 720 nM). Among these, 464T stem cells containing MDM2 gene amplification were most sensitive to AMG232 with IC
of 5.3 nM. Moreover, AMG232 exhibited higher selectivity against p53 wild-type cells over p53 mutant stem cells compared to RG7112 (average selectivity of 512-fold vs. 16.5-fold). Importantly, we also found that AMG232 is highly efficacious in three-dimensional (3D) tumor spheroids growth and effectively inhibits the stemness-related factors, Nestin and ZEB1. Our data provide new evidence that glioblastoma stem cells have high susceptibility to AMG232 suggesting the potential clinical implications of MDM2 inhibition for glioblastoma treatment. These will facilitate additional preclinical and clinical studies evaluating MDM2 inhibitors in glioblastoma and direct further efforts towards developing better MDM2-targeted therapeutics.
Objective
HLA association fine‐mapping studies have shown the effects of missense variants in HLA–DRB1 on rheumatoid arthritis (RA) susceptibility, prognosis, and autoantibody production. However, ...the phenotypic effects of expression changes in HLA–DRB1 remain poorly understood. Therefore, we investigated the allele‐specific expression of HLA–DRB1 and its effect on an HLA–DRβ1 structure–associated trait in RA.
Methods
We quantified the allele‐specific expression of each HLA–DRB1 3‐field classic allele in 48 Korean RA patients with anti–citrullinated protein antibodies (ACPAs) and 319 healthy European subjects by using both RNA sequencing and HLA–DRB1 genotype data to calculate the relative expression strength of multiple HLA–DRB1 alleles (n = 14 in Koreans and n = 25 in Europeans) in each population. The known association between ACPA level and alanine at position 74 of HLA–DRβ1 in ACPA‐positive RA was revisited to understand the phenotypic effect of allele‐specific expression of HLA–DRB1 by modeling multivariate logistic regression with the genomic dosage or relative expression dosage of Ala‐74 in 2 independent sets of 1,723 Korean RA patients with ACPA.
Results
The relative expression strength was highly allele‐specific, causing imbalanced allelic expression in HLA–DRB1 heterozygotes. The association between HLA‐DRβ1 Ala‐74 and ACPA level in RA was better explained by relative expression dosage of Ala‐74 than by the genomic dosage (change in Akaike's information criterion = −6.98). Moreover, the expression variance of Ala‐74 in Ala‐74 heterozygotes with no genomic variance of Ala‐74 was significantly associated with ACPA level (P = 2.26 × 10−3).
Conclusion
Our findings illustrate the advantage of integrating quantitative and qualitative changes in HLA–DRB1 into a single model for understanding HLA–DRB1 associations.
Glioblastoma is a highly aggressive and lethal brain tumor, with limited treatment options. Abnormal activation of the neddylation pathway is observed in glioblastoma, and the NEDD8-activating enzyme ...(NAE) inhibitor, MLN4924, was previously shown to be effective in glioblastoma cell line models. However, its effect has not been tested in patient-derived glioblastoma stem cells. We first analyzed public data to determine whether NEDD8 pathway proteins are important in glioblastoma development and patient survival. NAE1 and UBA3 levels increased in glioblastoma patients; high NEDD8 levels were associated with poor clinical outcomes. Immunohistochemistry results also supported this result. The effects of MLN4924 were evaluated in 4 glioblastoma cell lines and 15 patient-derived glioblastoma stem cells using high content analysis. Glioblastoma cell lines and patient-derived stem cells were highly susceptible to MLN4924, while normal human astrocytes were resistant. In addition, there were various responses in 15 patient-derived glioblastoma stem cells upon MLN4924 treatment. Genomic analyses indicated that MLN4924 sensitive cells exhibited enrichment of Extracellular Signal Regulated Kinase (ERK) and Protein kinase B (AKT, also known as PKB) signaling. We verified that MLN4924 inhibits ERK and AKT phosphorylation in MLN4924 sensitive cells. Our findings suggest that patient-derived glioblastoma stem cells in the context of ERK and AKT activation are sensitive and highly regulated by neddylation inhibition.
Abnormal regulation of β-catenin initiates an oncogenic program that serves as a main driver of many cancers. Albeit challenging, β-catenin is an attractive drug target due to its role in maintenance ...of cancer stem cells and potential to eliminate cancer relapse. We have identified C2, a novel β-catenin inhibitor, which is a small molecule that binds to a novel allosteric site on the surface of β-catenin. C2 selectively inhibits β-catenin, lowers its cellular load and significantly reduces viability of β-catenin-driven cancer cells. Through direct binding to β-catenin, C2 renders the target inactive that eventually activates proteasome system for its removal. Here we report a novel pharmacologic approach for selective inhibition of β-catenin via targeting a cryptic allosteric modulation site. Our findings may provide a new perspective for therapeutic targeting of β-catenin.
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