Development Of High-grade Gliomas Research Articles

Radiomics Features on Magnetic Resonance Images Can Predict C5aR1 Expression Levels and Prognosis in High-Grade Glioma.

The complement component C5a receptor 1 (C5aR1) regulates cancer immunity. This retrospective study aimed to assess its prognostic value in high-grade glioma (HGG) and predict C5aR1 expression using a radiomics approach. Among 298 patients with HGG, 182 with MRI data were randomly divided into training and test groups for radiomics analysis. We examined the association between C5aR1 expression and prognosis through Kaplan-Meier and Cox regression analyses. We used maximum relevance-minimum redundancy and recursive feature elimination algorithms for radiomics feature selection. We then built a support vector machine (SVM) and a logistic regression model, investigating their performances using receiver operating characteristic, calibration curves, and decision curves. C5aR1 expression was elevated in HGG and was an independent prognostic factor (hazard ratio = 3.984, 95% CI: 2.834-5.607). Both models presented with >0.8 area under the curve values in the training and test datasets, indicating efficient discriminatory ability, with SVM performing marginally better. The radiomics score calculated using the SVM model correlated significantly with overall survival (p < 0.01). Our results highlight C5aR1's role in HGG development and prognosis, supporting its potential as a prognostic biomarker. Our radiomics model can noninvasively and effectively predict C5aR1 expression and patient prognosis in HGG.

TMOD-18. DIRECT IN VIVO CRISPR SCREEN IDENTIFIES COOPERATING TUMOR SUPPRESSORS THAT DRIVE PROGRESSION OF IDH1-MUTANT LOW-GRADE GLIOMA TO AGGRESSIVE GLIOBLASTOMA

Abstract Low-grade glioma (LGG) are generally slowly growing brain cancers, that frequently undergo malignant progression to aggressive, secondary glioblastoma with a dismal prognosis. By combining genetically engineered Idh1-mutant mice with in vivo CRISPR gene editing we generated a mouse model faithfully recapitulating the founder mutations of LGG. Clonal activation of the neomorphic Idh1 R132H mutation cooperates with Trp53 and Atrx mutations to trigger development of brain tumors but only with ~30% penetrance and very long latency. To elucidate the molecular mechanisms underlying the malignant progression of IDH1-mutant LGG, we devised and deployed a direct in vivo CRISPR screen targeting genes commonly mutated in human IDH-mutant secondary glioblastoma. Stereotaxic delivery of a lentiviral sgRNA library targeting the mouse orthologs of these genes into the brain of Idh1 R132H ;Trp53;Atrx;Cas9 and control Idh1 wt ;Trp53;Atrx;Cas9 compound mutant mice resulted in rapid formation of tumors that recapitulate human Idh1-mutant glioblastoma. Deconvoluting the screen showed that PI3K pathway members Pten and Pik3ca as well as Notch1, Smarca4 and Fat1 are preferentially enriched in Idh1 R132H-tumors, while Rb1 and NF2 were enriched in Idh1 wt tumors. Co-mutation analysis further identified additional co-occurring driver combinations such as Bcor-Met, Olig2-Met, Olig2-Med12 or Bcor-Olig2. We validated the tumor suppressive function of Notch1 and Pten using conventional floxed knock-out alleles and found that Notch1 functions in a haploinsufficient manner. Interestingly, Idh1 R132H did not alter tumor latency or pathology in a high grade p53;Pten;Rb1 mutant background, indicating that the neomorphic IDH-mutations can drive low but not high grade glioma development. Our study provides a functional landscape of gliomagenesis suppressors in vivo.

Hormone exposure and its suppressive effect on risk of high-grade gliomas among patients with breast cancer

BackgroundPrior reports demonstrate the expression of estrogen and progesterone receptors in high-grade gliomas (HGGs), but the relationship between hormone receptor-positive disease and risk of HHGs in patients with breast cancer (BC) remains uncharacterized. MethodsUsing the SEER 18 registries (2000–2017), we examined the temporal trend of the incidence of HGGs and BC. The standardized incidence ratio was calculated to assess the risk of subsequent HGG in BC patients. ResultsDuring the study period, the incidence of BC and HGGs remained comparable for men and women. Among 976,134 patients with BC, we found a decreased incidence of HGGs in females, but not in males. Female BC patients with hormone receptor-positive disease were at a lower risk of developing glioblastoma and anaplastic astrocytoma. ConclusionOur study findings allude to the protective role of hormone exposure in the development of HGGs, which may lead to the development of therapies targeting hormonal pathways.

EPID-17. THE RELATIONSHIP OF HORMONE EXPOSURE IN BREAST CANCER AND SUBSEQUENT RISK OF HIGH GRADE GLIOMAS

Abstract BACKGROUND Women have a lower incidence of high grade gliomas (HGGs), which is thought to be related to sex differences and hormone exposure. The association between hormone dependent tumors in women and HGGs remains poorly investigated. METHODS The Surveillance, Epidemiology, and End Results (SEER) database of 18 Registries (2000–2017) was used to assess age-adjusted incidence rates and temporal trends of breast cancer (BC) and HGG. Female BC patients 18 years of age or older and with ductal or lobular BC were then assessed for the risk of subsequent HGG, calculated as the standardized incidence ratio (SIR). RESULTS A total of 976,134 patients diagnosed with BC between 2000–2017 were identified. The temporal trend of BC and HGG incidence rates remained comparable throughout the study, with a higher incidence of BC and lower incidence of HGGs in females. Female BC patients had a 22% lower risk of developing a HGG (SIR 0.78 [0.69–0.87], p&amp;lt; 0.05) compared to general population. HGG risk by age groups in BC females was significant, with a lower risk found in pre-menopausal women (Ages 18–50, SIR 0.66 [0.45–0.94] vs Ages 50+ SIR 0.79 [0.70–0.89], p&amp;lt; 0.05 for both). Among HGG tumors, a decreased risk of developing glioblastoma (SIR 0.83 [0.75–0.93], p&amp;lt; 0.05) and anaplastic astrocytoma (SIR 0.58 [0.35–90, p&amp;lt; 0.05), was found, but not for anaplastic oligodendrogliomas. CONCLUSIONS The findings of our study allude to the protective effect of hormone exposure in the development of HGGs, as shown by the lower risk in female patients with BC compared to the general population.

Abstract 43: HBEGF cooperates with Cdkn2a and Pten loss to form malignant gliomas

Abstract Malignant gliomas are aggressive brain tumors that carry a grim prognosis to over 10,000 patients a year in the United States. The highest grade tumor, glioblastoma, has an average survival of one year with the current standard of care, which includes surgical resection, radiotherapy, and temozolomide chemotherapy. Heparin-binding EGF-like growth factor (HBEGF), first discovered in macrophages as a mitogen for vascular smooth muscle cells, is a ligand for epidermal growth factor receptor, the most commonly amplified receptor-tyrosine kinase in glioblastoma. About 30% of glioblastomas express HBEGF, and it is also commonly upregulated in tumors that express the common EGFR mutant, EGFRvIII. To date, HBEGF has not been evaluated for its ability to promote the development of malignant gliomas in vivo. Using a method for somatic cell gene transfer, we show that HBEGF cooperates with loss of tumor suppressors Cdkn2a and Pten to form malignant gliomas in vivo. These tumors share many characteristics found in human glioblastoma such as necrosis and nuclear atypia. We also demonstrate using high-throughput sequencing that these tumors share a common gene signature to the human glioblastoma samples from The Cancer Genome Atlas study. No tumors were seen with loss of Cdkn2a and Pten alone, which are the two most common tumor suppressors altered in glioblastoma. Our findings demonstrate that HBEGF can drive the development of high grade gliomas in the context of Cdkn2a and Pten loss and that these tumors closely resemble the human disease. Citation Format: Clifford Shin, Sheri Holmen. HBEGF cooperates with Cdkn2a and Pten loss to form malignant gliomas. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Integrating Clinical Genomics and Cancer Therapy; Jun 13-16, 2015; Salt Lake City, UT. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(1_Suppl):Abstract nr 43.

Abstract 3454: LIN28 is expressed in glioblastomas and promotes KRAS-mediated transformation of human neural stem cells

Abstract The pluripotency factor LIN28 is activated in many cancers arising outside the central nervous system, but its role in brain tumors is poorly understood. LIN28 inhibits the maturation of let-7, which in turn represses KRAS, c-myc, HMGA2 and other oncogenic factors, many of which are known to be activated in glioblastoma (GBM). Because malignant gliomas are thought to arise from normal human neural stem cells (hNSC), we hypothesized that the stem cell factor LIN28 plays a role in the development of high grade gliomas. Using immunohistochemistry, we detected LIN28 protein in a subset of gliomas, with higher expression in GBMs than in lower grade tumors. To examine if LIN28 would facilitate transformation of hNSC, we infected these cells with lentivirus encoding LIN28 together with dominant negative R248W p53 (DN-p53), constitutively active KRAS (CA-KRAS) and hTERT (hNSC-LIN28/DN-p53/CA-KRAS/hTERT), which are all commonly dysregulated in GBM. As controls, hNSC were also infected with DN-p53/CA-KRAS/hTERT, LIN28/DN-p53/hTERT, DN-p53/hTERT, or with GFP. The lentivirus transduced hNSCs continued to express the stem cell markers CD133, SOX2, Nestin and OLIG2, and retained the potential to differentiate along neuronal and glial lineages. The LIN28/DN-p53/CA-KRAS/hTERT expressing cells showed increased proliferation by BrdU assay compared to normal hNSCs. To test their tumorigenecity in vivo, hNSC-LIN28/DN-p53/CA-KRAS/hTERT were injected into the brains of immunocompromised mice. Eight weeks after injection, 66.7% (12 of 18) of the mice developed invasive brain tumors resembling GBMs which were positive for Nestin and GFAP, and negative for synaptophysin. In contrast, control injections including hNSC-DN-p53/hTERT (5 mice), hNSC-LIN28/DN-p53/hTERT (5 mice) and hNSC-GFP (10 mice) did not generate tumors over 6 months. Interestingly, hNSC-DN-p53/CA-KRAS/hTERT cultures proliferated very poorly, suggesting that both LIN28 and activated KRAS may play key roles in transformation. In support of this possibility, we found using quantitative RT-PCR and western blotting that hNSC-LIN28/DN-p53/CA-KRAS/hTERT expressed higher levels of KRAS and phospho-MAPK than hNSC-DN-p53/CA-KRAS/hTERT lacking LIN28, suggesting this stem cell factor is required to facilitate MAPK activation and complete transformation of hNSCs. To further confirm the role of LIN28 in the tumorigenicity of GBMs, a tumor-derived neurosphere line (JHH-GBM14) was infected with LIN28 (GBM14-LIN28) or GFP control (GBM14-GFP) and injected as orthotopic xenografts into immunocompromised mice. In addition to forming brain tumors larger than GBM14-GFP controls, GBM14-LIN28 tumors significantly invaded into normal tissues including the corpus callosum and the contralateral brain. Our data show that LIN28 is expressed in human GBMs and that LIN28 can facilitate tumorigenicity in orthotopic GBM mouse models. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3454. doi:10.1158/1538-7445.AM2011-3454

Abstract 196: Functional role of death-associated protein 3 in high grade gliomas of childhood

Abstract Background: High grade gliomas (HGG) are highly invasive tumors and respond poorly to conventional treatments. Although significant progress has been made in understanding the molecular pathways that lead to the development of HGG in adults, comparatively few data is available for gliomas of childhood. The death-associated protein 3 (DAP3) is localized on the chromosomal region 1q21-22 that has been previously described as a region of frequent chromosomal gain associated with poor outcome in HGG. Moreover, DAP3 has been reported to be overexpressed and to play anti-apoptotic role in invasive glioblastoma cells. Methods: In the current study to investigate the functional role of DAP3 in pediatric versus adult HGG, we suppressed the endogenous DAP3 protein using DAP3-specific short hairpin RNA (shRNA) or chemical inhibitors of protein kinase C, and analyzed the phenotypic effect on glioma cell proliferation, migration, mitochondrial morphology and apoptosis. Results: We found that knockdown of DAP3 by shRNA induced mitochondrial fragmentation and apoptosis in pediatric glioma cell lines while in adult glioma cell lines it suppressed cell proliferation and reduced mitochondrial potential without inducing mitochondrial fragmentation. Specific chemical inhibition of the two classical PKC isoforms (PKCα and PKCβ) significantly reduced the expression of DAP3 protein in both pediatric and adult glioma cell lines. The inhibition of PKCα changed cell morphology, mitochondrial status and significantly suppressed proliferation and migration of both pediatric and adult glioma cell lines without associated caspase activation indicating that DAP3 may mediate nonapoptotic form of cell death in HGG. The suppression of PKCβ rendered pediatric glioma cells more sensitive to the apoptotic effect of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) through a caspase-dependent process as compared with adult glioma cells suggesting a possible implication of DAP3 in intrinsic and extrinsic pathways for apoptosis in pediatric HGG. Conclusion: Our findings confirmed the anti-apoptotic role of DAP3 in glioma cell biology suggesting that specific PKC isoforms mediated the DAP3 suppression of apoptosis in HGG and pointed out the specific functional role of this protein in mitochondrial maintenance. DAP3 may represent a novel target for the treatment of gliomas. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 196. doi:10.1158/1538-7445.AM2011-196

Inverse association of PPARγ agonists use and high grade glioma development

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have antineoplastic effects on gliomas in cell lines and animal models. In a retrospective chart review, we assessed the influence of PPARγ agonists on the odds of having a high grade glioma. We reviewed patients with a diagnosis of anaplastic astrocytoma and glioblastoma multiforme (GBM) between 1999 and 2008. Patients with hip fractures served as the control group. Multivariable unconditional logistic regression models were used to calculate the odds of diabetic hip fracture patients using a PPARγ agonist at time of diagnosis as compared to diabetic glioma patients. In addition, survival analysis was performed for all GBM patients. We identified 1602 hip fracture patients and 302 high grade glioma patients, 15 and 16% were diabetics, respectively. PPARγ agonists were used by 20% of diabetic hip fracture patients and by 6% of high grade glioma patients (chi-square P-value=0.02) with an odds ratio of 4.081 (95% CI: 1.119-14.881). In addition, there was no difference in survival for diabetic patients with GBM compared to non-diabetic patients with GBM. The prevalence of PPARγ agonist use was lower in the diabetic high grade glioma group when compared to diabetic hip fracture patients. These findings suggest that diabetic high grade glioma patients are not given PPARγ agonists as often as diabetic hip fracture patients even though these drugs are considered standard of care and should be equally distributed throughout both groups. This indicates a possible anti-neoplastic effect of PPARγ agonists in gliomas.

Abstract 5071: Defining the role of canonical MAPK signaling in glioma initiation and maintenance

Abstract Mutations in receptor tyrosine kinase (RTK) growth factor receptors e.g., EGFR, PDGFR, MET and ERBB2 which result in constitutive downstream signaling of the canonical mitogen activated protein kinase (MAPK) (e.g., RAS/RAF/MEK/ERK) and phosphatidylinositol 3-kinase (PI3K)/AKT pathways, are found in almost all World Health Organization (WHO) grade II, III, and IV astrocytomas. KRAS, BRAF and CRAF mutations occur in approximately 6%, 72% and 2% of low grade gliomas (WHO Grade I), respectively. A recent study also found a 5-fold increase in RAF serine/threonine kinase activity in a significant series of grade III and IV gliomas, coupled with a 12-fold increase in BRAF and a 2-fold increase in CRAF protein levels. By using an established glioma mouse model, it has been demonstrated that KRas, CRAF or BRAF expression in nestin expressing neural progenitor cells, combined with either Akt activation or Ink4a/Arf loss, leads to the development of high grade gliomas. Together, these data clearly demonstrate the importance of MAPK signaling in glioma development. However, KRAS, BRAF and CRAF are all differently regulated. To further validate a role for canonical MAPK signaling in glioma formation, we have evaluated the effect of constitutive MEK1 activity in glioma formation in vitro and in vivo. While expression of activated MEK1 alone is not sufficient for tumorigenesis, the combination of activated MEK1 and Akt, or MEK1 with Ink4a/Arf loss leads to glioma formation. To assess the efficacy of targeting MAPK signaling in gliomas, we treated a large panel human GBM cell lines with the MEK inhibitor PD0325901 alone and in combination with the PI3K/mTOR inhibitor BEZ235. Cell lines with the highest levels of ERK activation were the most sensitive to MEK inhibition while those with the highest levels of AKT activation were protected from apoptosis following MAPK inhibition. Treatment with BEZ235, in combination with PD0325901, caused significantly higher levels of apoptosis in the glioma cell lines. Importantly, neither treatment induced apoptosis in normal human astrocytes. Our studies demonstrate that activation and signaling through the MAPK pathway following Ink4a/Arf loss or Akt activation can give rise to high grade gliomas; moreover MAPK inhibition, when combined with PI3K/mTOR inhibition may prove to be an effective treatment for gliomas. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5071.

Abstract 4351: A mammalian mitochondrial ribosomal protein contributes to intrinsic and extrinsic pathways for apoptosis in high grade gliomas of childhood

Abstract Background: High grade gliomas (HGG) of childhood represent approximately 7% of pediatric brain tumors. They are highly invasive tumors and respond poorly to conventional treatments. Although significant progress has been made in understanding the molecular pathways that lead to the development of HGG in adults, comparatively few data is available for gliomas of childhood. The death-associated protein 3 (DAP3) is localized on the chromosomal region 1q21-22 that has been previously described as a region of frequent chromosomal gain in pediatric HGG. It encodes a 46 kDa mitochondrial ribosomal GTP-binding pro-apoptotic protein. DAP3 has been reported to be overexpressed in glioblastomas and to protect glioblastoma cells from camptothecin-induced apoptosis. Methods: In the current study, to investigate the functional role of DAP3 in pediatric HGG we suppressed the endogenous DAP3 using DAP3-specific short hairpin RNA (shRNA) and analyzed the mitochondrial morphology by immunofluorescence in vitro. Results: We found that repression of DAP3 by shRNA induced mitochondrial fragmentation and apoptosis in pediatric glioma cell lines while in adult glioma cell lines it reduced proliferation. Protein kinase C (PKC) has been implicated in the proliferation and apoptosis of glial tumors and has been suggested to phosphorylate DAP3 in mitochondria. Western blot analysis showed that adult glioma cells expressed higher levels of PKCα and lower levels of PKCβ as compared with pediatric glioma cell lines. Specific inhibition of the two PKC isoforms (PKCα and PKCβ) reduced the expression of DAP3 protein in both pediatric and adult glioma cell lines without affecting the mitochondrial morphology. The inhibition of PKCα in adult glioma cells significantly suppressed proliferation as compared with pediatric glioma cell lines. The suppression of PKCβ rendered pediatric glioma cells more sensitive to the apoptotic effect of TRAIL through a caspase-dependent process as compared with adult glioma cells suggesting a possible implication of DAP3 in intrinsic and extrinsic pathways for apoptosis in pediatric HGG. Our findings confirmed the anti-apoptotic role of DAP3 in glioma cell biology and pointed out the specific functional role of this protein in mitochondrial maintenance. Conclusion: The results suggest that the phosphorylation of DAP3 which may result from differential activation of specific PKC isoforms in glioma cells is required for functional suppression of apoptosis by DAP3 in HGG. DAP3 may represent a novel target for the treatment of gliomas. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4351.

Prior Hospitalization for Epilepsy, Diabetes, and Stroke and Subsequent Glioma and Meningioma Risk

We conducted a case-control study to evaluate the preclinical association between epilepsy, diabetes, and stroke and primary adult brain tumors. We first identified all 1,501 low-grade glioma, 4,587 high-grade glioma (HGG), and 4,193 meningioma cases reported to the Swedish Cancer Registry from 1987 to 1999. Next, controls (137,485) were randomly selected from the continuously updated Swedish Population Registry and matched to cases diagnosed that year on age and sex. Finally, cases and controls were linked to the Swedish Hospital Discharge Registry (1969-1999). We found that > or =8 years before HGG diagnosis (or control reference year) there was an elevated risk of HGG among people discharged with epilepsy [odds ratio (OR), 3.01; 95% confidence interval (95% CI), 1.73-5.22]. Two to 3 years before HGG diagnosis, this risk increased (OR, 5.33; 95% CI, 3.58-7.93) and was especially strong among people ages <55 years (OR, 13.49; 95% CI, 6.99-25.94). During this 2- to 3-year prediagnostic period, we also found an increased risk of HGG among people discharged with meningitis (OR, 3.02; 95% CI, 1.06-8.59) or viral encephalitis (OR, 12.64; 95% CI, 2.24-71.24). Results are similar for glioblastoma multiforme, low-grade glioma, and meningioma. In contrast, risk of HGG among people discharged with diabetes or stroke does not increase until year of brain tumor diagnosis. The occurrence of excess epilepsy > or =8 years before HGG diagnosis suggests a relatively long preclinical phase, but excess diabetes or stroke appear late in HGG development.

LGI1, a Putative Tumor Metastasis Suppressor Gene, Controls in Vitro Invasiveness and Expression of Matrix Metalloproteinases in Glioma Cells through the ERK1/2 Pathway

Gliomas take a number of different genetic routes in the progression to glioblastoma multiforme, a highly invasive variant that is mostly unresponsive to current therapies. Gliomas express elevated levels of matrix metalloproteinases (MMPs), which have been implicated in the control of proliferation and invasion as well as neovascularization. Progressive loss of LGI1 expression has been associated with the development of high grade gliomas. We have shown previously that the forced re-expression of LGI1 in different glioma cells inhibits proliferation, invasiveness, and anchorage-independent growth in cells null for its expression. Here, using Affymetrix gene chip analysis, we show that reexpression of LGI1 in T98G cells results in the down-regulation of several MMP genes, in particular MMP1 and MMP3. LGI1 expression also results in the inhibition of ERK1/2 phosphorylation but not p38 phosphorylation. Inhibition of the MAPK pathway using the pharmacological inhibitors PD98059, U0126, and SB203580 in T98G LGI1-null cells inhibits MMP1 and MMP3 production in an ERK1/2-dependent manner. Treatment of LGI1-expressing cells with phorbol myristate acetate prevents the inhibition of MMP1/3 and restores invasiveness and ERK1/2 phosphorylation, suggesting that LGI1 acts through the ERK/MAPK pathway. Furthermore, LGI1 expression promotes phosphorylation of AKT, which leads to phosphorylation of Raf1(Ser-259), an event shown previously to negatively regulate ERK1/2 signaling. These data suggest that LGI1 plays a major role in suppressing the production of MMP1/3 through the phosphatidylinositol 3-kinase/ERK pathway. Loss of LGI1 expression, therefore, may be an important event in the progression of gliomas that leads to a more invasive phenotype in these cells.