[Show abstract][Hide abstract] ABSTRACT: Glioblastoma (GBM) is the most aggressive human brain tumor. Although several molecular subtypes of GBM are recognized, a robust molecular prognostic marker has yet to be identified. Here,wereport that the stemness regulator Sox2 is a new, clinically important target of microRNA-21 (miR-21) in GBM, with implications for prognosis. Using the MiR-21-Sox2 regulatory axis, approximately half of all GBM tumors present in the Cancer Genome Atlas (TCGA) and in-house patient databases can be mathematically classified into high miR-21/low Sox2 (Class A) or low miR-21/high Sox2 (Class B) subtypes. This classification reflects phenotypically and molecularly distinct characteristics and is not captured by existing classifications. Supporting the distinct nature of the subtypes, gene set enrichment analysis of the TCGA dataset predicted that Class A and Class B tumors were significantly involved in immune/inflammatory response and in chromosome organization and nervous system development, respectively. Patients with ClassBtumors had longer overall survival than those with Class A tumors. Analysis of both databases indicated that the Class A/Class B classification is a better predictor of patient survival than currently used parameters. Further, manipulation of MiR-21-Sox2 levels in orthotopic mouse models supported the longer survival of the Class B subtype. The MiR-21-Sox2 association was also found in mouse neural stem cells and in the mouse brain at different developmental stages, suggesting a role in normal development. Therefore, this mechanism-based classification suggests the presence of two distinct populations of GBM patients with distinguishable phenotypic characteristics and clinical outcomes.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 11/2015; 35(45):15097-15112. DOI:10.1523/JNEUROSCI.1265-15.2015 · 6.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gliosarcoma is classified by the World Health Organization as a variant of glioblastoma. These tumors exhibit biphasic histologic and immunophenotypic features, reflecting both glial and mesenchymal differentiation. Gliosarcomas can be further classified into primary (de novo) tumors, and secondary gliosarcomas, which are diagnosed at recurrence after a diagnosis of glioblastoma. Using a retrospective review, patients seen at MD Anderson Cancer Center between 2004 and 2014 with a pathology-confirmed diagnosis of gliosarcoma were identified. 34 patients with a diagnosis of gliosarcoma seen at the time of initial diagnosis or at recurrence were identified (24 primary gliosarcomas (PGS), 10 secondary gliosarcomas (SGS)). Molecular analysis performed on fourteen patients revealed a high incidence of TP53 mutations and, rarely, EGFR and IDH mutations. Median overall survival (OS) for all patients was 17.5 months from the diagnosis of gliosarcoma, with a progression free survival (PFS) of 6.4 months. Comparing PGS with SGS, the median OS was 24.7 and 8.95 months, respectively (from the time of sarcomatous transformation in the case of SGS). The median OS in SGS patients from the initial diagnosis of GB was 25 months, with a PFS of 10.7 months. Molecular analysis revealed a higher than expected rate of TP53 mutations in GS patients and, typical of primary glioblastoma, IDH mutations were uncommon. Though our data shows improved outcomes for both PGS and SGS when compared to the literature, this is most likely a reflection of selection bias of patients treated on clinical trials at a quaternary center.
Journal of Neuro-Oncology 09/2015; 125(2). DOI:10.1007/s11060-015-1930-y · 3.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ten to twenty percent of newly diagnosed glioblastoma (GBM) patients initially present with multiple lesions, termed multifocal or multicentric GBM (M-GBM). The prognosis of these patients is poorer than that of solitary GBM (S-GBM) patients. However, it is unknown whether multifocality has a genetic, epigenetic, or molecular basis. Here, we identified the genetic and epigenetic characteristics of M-GBM by performing a comprehensive analysis of multidimensional data, including imaging, genetic, epigenetic, and gene expression profiles, from 30 M-GBM cases in The Cancer Genome Atlas database and comparing the results with those of 173 S-GBM cases. We found that M-GBMs had no IDH1, ATRX, or PDGFRA mutations and were significantly associated with the mesenchymal subtype. We also identified the CYB5R2 gene to be hypo-methylated and overexpressed in M-GBMs. The expression level of CYB5R2 was significantly associated with patient survival in two major independent GBM cohorts, totaling 758 cases. The IDH1 mutation was markedly associated with CYB5R2 promoter methylation, but the survival influence of CYB5R2 was independent of IDH1 mutation status. CYB5R2 expression was significantly associated with collagen maturation and the catabolic process and immunoregulation pathways. These results reveal that M-GBMs have some underlying genetic and epigenetic characteristics that are associated with poor prognosis and that CYB5R2 is a new epigenetic marker for GBM prognosis.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND
Diffuse low-grade and intermediate-grade gliomas (which together make up the lower-grade gliomas, World Health Organization grades II and III) have highly variable clinical behavior that is not adequately predicted on the basis of histologic class. Some are indolent; others quickly progress to glioblastoma. The uncertainty is compounded by interobserver variability in histologic diagnosis. Mutations in IDH, TP53, and ATRX and codeletion of chromosome arms 1p and 19q (1p/19q codeletion) have been implicated as clinically relevant markers of lower-grade gliomas.
We performed genomewide analyses of 293 lower-grade gliomas from adults, incorporating exome sequence, DNA copy number, DNA methylation, messenger RNA expression, microRNA expression, and targeted protein expression. These data were integrated and tested for correlation with clinical outcomes.
Unsupervised clustering of mutations and data from RNA, DNA-copy-number, and DNA-methylation platforms uncovered concordant classification of three robust, nonoverlapping, prognostically significant subtypes of lower-grade glioma that were captured more accurately by IDH, 1p/19q, and TP53 status than by histologic class. Patients who had lower-grade gliomas with an IDH mutation and 1p/19q codeletion had the most favorable clinical outcomes. Their gliomas harbored mutations in CIC, FUBP1, NOTCH1, and the TERT promoter. Nearly all lower-grade gliomas with IDH mutations and no 1p/19q codeletion had mutations in TP53 (94%) and ATRX inactivation (86%). The large majority of lower-grade gliomas without an IDH mutation had genomic aberrations and clinical behavior strikingly similar to those found in primary glioblastoma.
The integration of genomewide data from multiple platforms delineated three molecular classes of lower-grade gliomas that were more concordant with IDH, 1p/19q, and TP53 status than with histologic class. Lower-grade gliomas with an IDH mutation either had 1p/19q codeletion or carried a TP53 mutation. Most lower-grade gliomas without an IDH mutation were molecularly and clinically similar to glioblastoma.
(Funded by the National Institutes of Health)
New England Journal of Medicine 06/2015; 372(26):2481-2498. DOI:10.1056/NEJMoa1402121 · 55.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Insulin-like growth factor binding protein 2 (IGFBP2) is a pleiotropic oncogenic protein that has both extracellular and intracellular functions. Despite a clear causal role in cancer development, the tumor-promoting mechanisms of IGFBP2 are poorly understood. The contributions of intracellular IGFBP2 to tumor development and progression are also unclear. Here we present evidence that both exogenous IGFBP2 treatment and cellular IGFBP2 overexpression lead to aberrant activation of epidermal growth factor receptor (EGFR), which subsequently activates signal transducer and activator of transcription factor 3 (STAT3) signaling. Furthermore, we demonstrate that IGFBP2 augments the nuclear accumulation of EGFR to potentiate STAT3 transactivation activities, via activation of the nuclear EGFR signaling pathway. Nuclear IGFBP2 directly influences the invasive and migratory capacities of human glioblastoma cells, providing a direct link between intracellular (and particularly nuclear) IGFBP2 and cancer hallmarks. These activities are also consistent with the strong association between IGFBP2 and STAT3-activated genes derived from The Cancer Genome Atlas database for human glioma. A high level of all three proteins (IGFBP2, EGFR and STAT3) was strongly correlated with poorer survival in an independent patient data set. These results identify a novel tumor-promoting function for IGFBP2 of activating EGFR/STAT3 signaling and facilitating EGFR accumulation in the nucleus, thereby deregulating EGFR signaling by two distinct mechanisms. As targeting EGFR in glioma has been relatively unsuccessful, this study suggests that IGFBP2 may be a novel therapeutic target.Oncogene advance online publication, 20 April 2015; doi:10.1038/onc.2015.131.
[Show abstract][Hide abstract] ABSTRACT: Akt is a robust oncogene that plays key roles in the development and progression of many cancers, including glioma. We evaluated the differential propensities of the Akt isoforms toward progression in the well-characterized RCAS/Ntv-a mouse model of PDGFB-driven low grade glioma. A constitutively active myristoylated form of Akt1 did not induce high-grade glioma (HGG). In stark contrast, Akt2 and Akt3 showed strong progression potential with 78% and 97% of tumors diagnosed as HGG, respectively. We further revealed that significant variations in polarity and hydropathy values among the Akt isoforms in both the pleckstrin homology domain (P domain) and regulatory domain (R domain) were critical in mediating glioma progression. Gene expression profiles from representative Akt-derived tumors indicated dominant and distinct roles for Akt3, consisting primarily of DNA repair pathways. TCGA data from human GBM closely reflected the DNA repair function, as Akt3 was significantly correlated with a 76-gene signature DNA repair panel. Consistently, compared with Akt1 and Akt2 overexpression models, Akt3-expressing human GBM cells had enhanced activation of DNA repair proteins, leading to increased DNA repair and subsequent resistance to radiation and temozolomide. Given the wide range of Akt3-amplified cancers, Akt3 may represent a key resistance factor.
Proceedings of the National Academy of Sciences 03/2015; 112(11). DOI:10.1073/pnas.1414573112 · 9.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
The immune therapeutic potential of microRNAs (miRNAs) in the context of tumor-mediated immune suppression has not been previously described for monocyte-derived glioma-associated macrophages, which are the largest infiltrating immune cell population in glioblastomas and facilitate gliomagenesis.
An miRNA microarray was used to compare expression profiles between human glioblastoma-infiltrating macrophages and matched peripheral monocytes. The effects of miR-142-3p on phenotype and function of proinflammatory M1 and immunosuppressive M2 macrophages were determined. The therapeutic effect of miR-142-3p was ascertained in immune-competent C57BL/6J mice harboring intracerebral GL261 gliomas and in genetically engineered Ntv-a mice bearing high-grade gliomas. Student t test was used to evaluate the differences between ex vivo datasets. Survival was analyzed with the log-rank test and tumor sizes with linear mixed models and F test. All statistical tests were two-sided.
miR-142-3p was the most downregulated miRNA (approximately 4.95-fold) in glioblastoma-infiltrating macrophages. M2 macrophages had lower miR-142-3p expression relative to M1 macrophages (P = .03). Overexpression of miR-142-3p in M2 macrophages induced selective modulation of transforming growth factor beta receptor 1, which led to subsequent preferential apoptosis in the M2 subset (P = .01). In vivo miR-142-3p administration resulted in glioma growth inhibition (P = .03, n = 5) and extended median survival (miR-142-3p-treated C57BL/6J mice vs scramble control: 31 days vs 23.5 days, P = .03, n = 10; miR-142-3p treated Ntv-a mice vs scramble control: 32 days vs 24 days, P = .03, n = 9), with an associated decrease in infiltrating macrophages (R (2) = .303).
These data indicate a unique role of miR-142-3p in glioma immunity by modulating M2 macrophages through the transforming growth factor beta signaling pathway.
JNCI Journal of the National Cancer Institute 08/2014; 106(8). DOI:10.1093/jnci/dju162 · 12.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Rosette-forming glioneuronal tumor (WHO grade I) is a rare neoplasm primarily arising in young adults that is characterized by distinctive neurocytic rosette formation, a spindled glial component resembling pilocytic astrocytoma, and a high incidence of PIK3CA mutation. Low-grade diffuse astrocytoma (WHO grade II), on the other hand, is far more common and is characterized by a high incidence of IDH mutation. Here we report a patient with simultaneous presentation of a midbrain-cerebellar rosetteforming glioneuronal tumor and a cerebral diffuse astrocytoma. Molecular characterization of both tumors confirmed characteristic, mutually exclusive, distinct signatures, with the rosette-forming glioneuronal tumor exhibiting a previously unreported novel PIK3CA gene mutation.
[Show abstract][Hide abstract] ABSTRACT: While World Health Organization (WHO) grading of meningioma stratifies patients according to recurrence risk overall, there is substantial within-grade heterogeneity with respect to recurrence-free survival (RFS). Most meningiomas are graded according to mitotic counts per unit area on H&E sections, a method potentially confounded by tumor cellularity, as well as potential limitations of accurate mitotic figure detection on routine histology. To refine mitotic figure assessment we evaluated 363 meningiomas with phospho-histoneH3(Ser10), and determined the mitotic index (number of mitoses per 1000 tumor cells). The median mitotic indices among WHO grades I (n=268), II (n=84), and III (n=11) tumors were 1, 4, and 12, Classification and regression tree analysis to categorize cutoffs identified 3 subgroups defined by mitotic indices of 0-2, 3-4, and ≥5, which on univariate analysis were associated with RFS (p<0.01). In multivariate analysis, mitotic index subgrouped in this manner was significantly associated with RFS (p<0.01) after adjustment for Simpson grade, WHO grade, and MIB-1 index. Mitotic index was then examined within individual WHO grade, showing that for grade I and II meningiomas, mitotic index can add additional information to RFS risk. The results suggest that the use of a robust mitotic marker in meningioma could refine risk stratification.
[Show abstract][Hide abstract] ABSTRACT: Major discoveries in the biology of nervous system tumors have raised the question of how non-histological data such as molecular information can be incorporated into the next World Health Organization (WHO) classification of central nervous system tumors. To address this question, a meeting of neuropathologists with expertise in molecular diagnosis was held in Haarlem, The Netherlands, under the sponsorship of the International Society for Neuropathology (ISN). Prior to the meeting, participants solicited input from clinical colleagues in diverse neuro-oncological specialties. The present “white paper” catalogues the recommendations of the meeting, at which a consensus was reached that incorporation of molecular information into the next WHO classification should follow a set of provided “ISN-Haarlem” guidelines. Salient recommendations include that: 1) diagnostic entities should be defined as narrowly as possible to optimize interobserver reproducibility, clinicopathological predictions and therapeutic planning; 2) diagnoses should be “layered” with histologic classification, WHO grade, and molecular information listed below an “integrated diagnosis”; 3) determinations should be made for each tumor entity as to whether molecular information is required, suggested or not needed for its definition; 4) some pediatric entities should be separated from their adult counterparts; 5) input for guiding decisions regarding tumor classification should be solicited from experts in complementary disciplines of neuro-oncology and 6) entity-specific molecular testing and reporting formats should be followed in diagnostic reports. It is hoped that these guidelines will facilitate the forthcoming update of the 4th Edition of the WHO classification of central nervous system tumors.
[Show abstract][Hide abstract] ABSTRACT: The addition of anti-angiogenic therapy to the few treatments that are available to patients with malignant gliomas was based on the fact that these tumors are highly vascularized and on findings from initial preclinical and clinical studies which showed encouraging results. However, tumors that initially respond to this therapy invariably recur with the acquisition of highly aggressive and invasive phenotype. Although several myeloid populations have been associated to the recurrence of these tumors, a specific targetable population has not been yet identified as responsible for the heightened invasion observed upon antiangiogenesis therapies.
[Show abstract][Hide abstract] ABSTRACT: Delta-24-RGD is a novel replication-competent, tumor-selective, oncolytic adenovirus with enhanced infectivity. Based on promising
preclinical studies, we undertook a first-in-human Phase I clinical trial with biological endpoints in order to assess the
capacity of Delta-24-RGD to replicate in human gliomas, and to determine safety and initial efficacy. Patients with recurrent
high-grade gliomas were enrolled in one of two arms. Group A (clinical assessment group) received a single intratumoral injection
of Delta-24-RGD into biopsy-proven recurrent glioma. Group B (biological endpoint group) received an initial intratumoral
injection through an implanted catheter followed 14 days later by en bloc tumor/catheter resection (to obtain post-treatment
specimens) and subsequent injection of Delta-24-RGD into the post-resection cavity. Dose was escalated in 8 cohorts (1x107-3x1010vp). Histological analysis of post-treatment en bloc surgical specimens proved for the first time that Delta-24-RGD is capable
of infecting, replicating in, and killing/lysing glioma tumor cells (Group B; N = 12). Delta-24-RGD resulted in no toxicity
and the MTD was 3 × 1010vp (Group A; N = 25). Outcome analyses show an overall median survival of 11 months. Remarkably, complete responses were seen
in 3 patients (12%) all of whom are still alive with no evidence of disease 3.2, 2 and 1.75 years after treatment. Serial
MRIs revealed increased enhancement before tumor regression, consistent with inflammatory-mediated responses. Histological
analysis of resected tumor from a symptomatic patient in Arm A during the period of increased MRI-enhancement identified macrophages
and CD8 T-cells with only rare tumor cells. Compared with all other patients, the 3-responders had 10-fold to 1000-fold increases
in Interleukin-12p70 (which induces Th1-responses and cell-mediated immunity). In conclusion, Delta-24-RGD is a new oncolytic virus with a favorable toxicity-profile
that is capable of cycles of infection-replication-lysis in human glioma cells, and that can produce durable complete-responses
in subsets of patients. Viral-induced anti-tumor-immunity likely plays a role in the anti-glioma effect.