Glioblastoma is refractory to conventional therapies. The bromodomain and extraterminal domain (BET) proteins are epigenetic readers that selectively bind to acetylated lysine residues on histone ...tails. These proteins recently emerged as important therapeutic targets in NUT midline carcinoma and several types of hematopoietic cancers. In this study, the therapeutic potential of a novel BET bromodomain inhibitor, JQ1, was assessed in a panel of genetically heterogeneous glioblastoma samples.
The antineoplastic effects of JQ1 were shown using ex vivo cultures derived from primary glioblastoma xenograft lines and surgical specimens of different genetic background. The in vivo efficacy was assessed in orthotopic glioblastoma tumors.
We showed that JQ1 induced marked G1 cell-cycle arrest and apoptosis, which was phenocopied by knockdown of individual BET family members. JQ1 treatment resulted in significant changes in expression of genes that play important roles in glioblastoma such as c-Myc, p21(CIP1/WAF1), hTERT, Bcl-2, and Bcl-xL. Unlike the observations in some hematopoietic cancer cell lines, exogenous c-Myc did not significantly protect glioblastoma cells against JQ1. In contrast, ectopically expressed Bcl-xL partially rescued cells from JQ1-induced apoptosis, and knockdown of p21(CIP1/WAF1) attenuated JQ1-induced cell-cycle arrest. Cells genetically engineered for Akt hyperactivation or p53/Rb inactivation did not compromise JQ1 efficacy, suggesting that these frequently mutated signaling pathways may not confer resistance to JQ1. Furthermore, JQ1 significantly repressed growth of orthotopic glioblastoma tumors.
Our results suggest potentially broad therapeutic use of BET bromodomain inhibitors for treating genetically diverse glioblastoma tumors.
Aberrant activation of EGFR is a hallmark of glioblastoma. However, EGFR inhibitors exhibit at best modest efficacy in glioblastoma. This is in sharp contrast with the observations in EGFR-mutant ...lung cancer. We examined whether activation of functionally redundant receptor tyrosine kinases (RTKs) conferred resistance to EGFR inhibitors in glioblastoma.
We collected a panel of patient-derived glioblastoma xenograft (PDX) lines that maintained expression of wild-type or mutant EGFR in serial xenotransplantation and tissue cultures. Using this physiologically relevant platform, we tested the abilities of several RTK ligands to protect glioblastoma cells against an EGFR inhibitor, gefitinib. Based on the screening results, we further developed a combination therapy cotargeting EGFR and insulin receptor (InsR)/insulin-like growth factor 1 receptor (IGF1R).
Insulin and IGF1 induced significant protection against gefitinib in the majority of EGFR-dependent PDX lines with one exception that did not express InsR or IGF1R. Blockade of the InsR/IGF1R pathway synergistically improved sensitivity to gefitinib or dacomitinib. Gefitinib alone effectively attenuated EGFR activities and the downstream MEK/ERK pathway. However, repression of AKT and induction of apoptosis required concurrent inhibition of both EGFR and InsR/IGF1R. A combination of gefitinib and OSI-906, a dual InsR/IGF1R inhibitor, was more effective than either agent alone to treat subcutaneous glioblastoma xenograft tumors.
Our results suggest that activation of the InsR/IGF1R pathway confers resistance to EGFR inhibitors in EGFR-dependent glioblastoma through AKT regulation. Concurrent blockade of these two pathways holds promise to treat EGFR-dependent glioblastoma.
Abstract
BACKGROUND
Ventricular entry during glioblastoma resection and tumor contact with the subventricular zone (SVZ) have both been shown to associate with development of hydrocephalus, ...leptomeningeal dissemination, distant parenchymal recurrence, and decreased survival. However, prior studies did not analyze these variables together in a single-patient population; therefore, it is unknown which is an independent predictor of these outcomes.
OBJECTIVE
To conduct a comparative outcome analysis of surgical ventricular entry and SVZ contact by glioblastoma in a retrospective cohort of 232 patients.
METHODS
Outcomes studied included hydrocephalus, leptomeningeal dissemination, distant tumor recurrences, and progression-free (PFS) and overall (OS) survival. The Cox proportional regression analyses were adjusted for age at diagnosis, preoperative Karnofsky performance status score, extent of resection, temozolomide and radiation treatments, and tumor molecular status (specifically, IDH1/2 mutation and MGMT promoter methylation).
RESULTS
Surgical ventricular entry, SVZ-contacting glioblastoma, hydrocephalus, leptomeningeal dissemination, and distant recurrences were observed in 85 (36.6%), 114 (49.1%), 19 (8.2%), 78 (33.6%), and 59 (25.4%) patients, respectively. Multivariate, adjusted analysis revealed SVZ tumor contact—but not ventricular entry—associated with hydrocephalus (hazard ratio, HR, 4.20 1.13-15.7, P = .03), leptomeningeal dissemination (HR 1.93 1.14-3.28, P = .01), PFS (HR 2.10 1.53-2.88, P < .001), and OS (HR 1.90 1.35-2.67, P < .001). Distant recurrences were not associated with either. No interaction between the 2 variables was statistically noted.
CONCLUSION
SVZ contact by glioblastoma was independently associated with the development of hydrocephalus, leptomeningeal dissemination, and decreased survival. SVZ tumor contact was associated with ventricular entry during surgical resections, which did not independently correlate with these outcomes.
OBJECTIVE Antiepileptic drugs (AEDs) are often administered prophylactically following brain tumor resection. With conflicting evidence and unestablished guidelines, however, the nature of this ...practice among tumor surgeons is unknown. METHODS On November 24, 2015, a REDCap (Research Electronic Database Capture) survey was sent to members of the AANS/CNS Section on Tumors to query practice patterns. RESULTS Responses were received from 144 individuals, including 18.8% of board-certified neurosurgeons surveyed (across 86 institutions, 16 countries, and 5 continents). The majority reported practicing in an academic setting (85%) as a tumor specialist (71%). Sixty-three percent reported always or almost always prescribing AED prophylaxis postoperatively in patients with a supratentorial brain tumor without a prior seizure history. Meanwhile, 9% prescribed occasionally and 28% rarely prescribed AED prophylaxis. The most common agent was levetiracetam (85%). The duration of seizure prophylaxis varied widely: 25% of surgeons administered prophylaxis for 7 days, 16% for 2 weeks, 21% for 2 to 6 weeks, and 13% for longer than 6 weeks. Most surgeons (61%) believed that tumor pathology influences epileptogenicity, with high-grade glioma (39%), low-grade glioma (31%), and metastases (24%) carrying the greatest seizure risk. While the majority used prophylaxis, 62% did not believe or were unsure if prophylactic AEDs reduced seizures postoperatively. The vast majority (82%) stated that a well-designed randomized trial would help guide their future clinical decision making. CONCLUSIONS Wide knowledge and practice gaps exist regarding the frequency, duration, and setting of AED prophylaxis for seizure-naive patients undergoing brain tumor resection. Acceptance of universal practice guidelines on this topic is unlikely until higher-level evidence supporting or refuting the value of modern seizure prophylaxis is demonstrated.
Purpose
The need to detect and quantify brain lactate accurately by MRS has stimulated the development of editing sequences based on J coupling effects. In J‐difference editing of lactate, threonine ...can be co‐edited and it contaminates lactate estimates due to the spectral proximity of the coupling partners of their methyl protons. We therefore implemented narrow‐band editing 180° pulses (E180) in MEGA‐PRESS acquisitions to resolve separately the 1.3‐ppm resonances of lactate and threonine.
Methods
Two 45.3‐ms rectangular E180 pulses, which had negligible effects 0.15‐ppm away from the carrier frequency, were implemented in a MEGA‐PRESS sequence with TE 139 ms. Three acquisitions were designed to selectively edit lactate and threonine, in which the E180 pulses were tuned to 4.1 ppm, 4.25 ppm, and a frequency far off resonance. Editing performance was validated with numerical analyses and acquisitions from phantoms. The narrow‐band E180 MEGA and another MEGA‐PRESS sequence with broad‐band E180 pulses were evaluated in six healthy subjects.
Results
The 45.3‐ms E180 MEGA offered a difference‐edited lactate signal with lower intensity and reduced contamination from threonine compared to the broad‐band E180 MEGA. The 45.3 ms E180 pulse had MEGA editing effects over a frequency range larger than seen in the singlet‐resonance inversion profile. Lactate and threonine in healthy brain were both estimated to be 0.4 ± 0.1 mM, with reference to N‐acetylaspartate at 12 mM.
Conclusion
Narrow‐band E180 MEGA editing minimizes threonine contamination of lactate spectra and may improve the ability to detect modest changes in lactate levels.
We studied 571 patients with intracranial meningioma for clinical characteristics and tumor location associated with high grade meningioma (WHO II/III).
Patients were participants in a multicentre ...epidemiologic study of risk factors for primary brain tumors including meningioma recruited from September 2005 to November 2019. We included patients 18 or older with a recent diagnosis of a primary intracranial meningioma of any subtype (ICD9/10: 9530-0, 9531-0, 9532-0, 9537-0, 9533-0, 9534-0, 9530-0, 9538-1, 9538-3) who were enrolled at neuro-oncology and neuro-surgery clinics in the southeastern U.S.
The median patient age was 58 years (IQR: 48-68) and the majority of patients were female (n = 415; 72.7%) and Caucasian (n = 516; 90.4%). Most patients were symptomatic (n = 460; 80.6%) and their tumours more commonly occurred in a non-skull base location (n = 298; 52.2%). A total of 86 patients (15.0%) had a WHO grade II/III meningioma. Compared to patients with WHO grade I tumours, patients with WHO II/III meningiomas were over 3-times more likely to be male (odds ratio (OR): 3.25; 95% confidence interval (CI): 1.98, 5.35) adjusting for age, race, symptomatic presentation, and skull-based location. Moreover, a WHO grade II/III meningioma was substantially less likely to be observed in asymptomatic patients (OR: 0.15, 95% CI: 0.04, 0.42), and in patients with a skull-based tumour (OR: 0.40, 95% CI: 0.24, 0.66), adjusting for other factors. Male gender, symptomatic tumour, and a non-skull base location were independently associated with WHO grade II/III meningioma.
These findings may shed additional light on the underlying pathogenesis of meningioma.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The ventricular-subventricular zone (V-SVZ), which lies in the walls of the lateral ventricles (LV), is the largest neurogenic niche within the adult brain. Whether radiographic contact with the LV ...influences survival in glioblastoma (GBM) patients remains unclear. We assimilated and analyzed published data comparing survival in GBM patients with (LV+GBM) and without (LV-GBM) radiographic LV contact. PubMed, EMBASE, and Cochrane electronic databases were searched. Fifteen studies with survival data on LV+GBM and LV-GBM patients were identified. Their Kaplan–Meier survival curves were digitized and pooled for generation of median overall (OS) and progression free (PFS) survivals and log-rank hazard ratios (HRs). The log-rank and reported multivariate HRs after accounting for the common predictors of GBM survival were analyzed separately by meta-analyses. The calculated median survivals (months) from pooled data were 12.95 and 16.58 (OS), and 4.54 and 6.25 (PFS) for LV+GBMs and LV-GBMs, respectively, with an overall log-rank HRs of 1.335 1.204–1.513 (OS) and 1.387 1.225–1.602 (PFS). Meta-analysis of log-rank HRs resulted in summary HRs of 1.58 1.35–1.85 (OS, 10 studies) and 1.41 1.22–1.64 (PFS, 5 studies). Meta-analysis of multivariate HRs resulted in summary HRs of 1.35 1.14–1.58 (OS, 6 studies) and 1.64 0.88–3.05 (PFS, 3 studies). Patients with GBM contacting the LV have lower survival. This effect may be independent of the common predictors of GBM survival, suggesting a clinical influence of V-SVZ contact on GBM biology.
To compare living wages and salaries at US residency programs.
It is unknown how resident salary compares to living wages across the United States (US).
Cross-sectional analysis of publicly available ...resident salary affordability from training centers with post-graduate-year (PGY)-1 through PGY-7 resident compensation for 2022-2023 was compared with the Massachusetts Institute of Technology (MIT) Living-Wage Calculator. Resident salary to living wage ratios were calculated using PGY-4 salary for each family composition. Univariate and multivariable analysis of PGY-4 salary affordability was performed, accounting for proportion of expected living wages to taxes, transportation, housing, healthcare, childcare, and food, as well as unionization and state income-tax.
118 residency programs, representing over 60% of US trainees, were included, 20 (17%) of which were unionized. Single-parent families were unable to earn a living wage until PGY-7. Residents with 1 child in 2-adult (single-income) and 2-adult (dual-income) families earn below living wages until PGY-5 and PGY-3, respectively. Residents with more than 1 child never earn a living wage. Multivariable regression analysis using PGY-4 salary: living wage ratios in single-child, 2-parent homes showed food expense and unionization status were consistent predictors of affordability. Unionization was associated with lower affordability pre-stipend, almost equivalent affordability post-stipend, and lower affordability post-stipend and union dues.
Resident salaries often preclude residents with children from earning a living wage. Unionization is not associated with increased resident affordability in this cross-sectional analysis. All annual reimbursement data should be centrally compiled, and additional stipends should be considered for residents with children.
Abstract Increasing evidence points to a fundamental role for cancer stem cells (CSC) in the initiation and propagation of many tumors. As such, in the context of glioblastoma multiforme (GBM), the ...development of treatment strategies specifically targeted towards CSC-like populations may hold significant therapeutic promise. To this end, we now report that the cell surface chemokine receptor, CXCR4, a known mediator of cancer cell proliferation and invasion, is overexpressed in primary glioblastoma progenitor cells versus corresponding differentiated tumor cells. Furthermore, administration of CXCL12, the only known ligand for CXCR4, stimulates a specific and significant proliferative response in progenitors but not differentiated tumor cells. Taken together, these results implicate an important role for the CXCR4 signaling mechanism in glioma CSC biology and point to the therapeutic potential of targeting this pathway in patients with GBM.
The goals of this study were to report the clinical presentation, radiographic findings, operative strategy, and outcomes among patients with temporal bone encephaloceles and cerebrospinal fluid ...fistulas (CSFFs) and to identify clinical variables associated with surgical outcome.
A retrospective case series including all patients who underwent a middle fossa craniotomy or combined mastoid-middle cranial fossa repair of encephalocele and/or CSFF between 2000 and 2012 was accrued from 2 tertiary academic referral centers.
Eighty-nine consecutive surgeries (86 patients, 59.3% women) were included. The mean age at time of surgery was 52.3 years, and the left side was affected in 53.9% of cases. The mean delay between symptom onset and diagnosis was 35.4 months, and the most common presenting symptoms were hearing loss (92.1%) and persistent ipsilateral otorrhea (73.0%). Few reported a history of intracranial infection (6.7%) or seizures (2.2%). Thirteen (14.6%) of 89 cases had a history of major head trauma, 23 (25.8%) were associated with chronic ear disease without prior operation, 17 (19.1%) occurred following tympanomastoidectomy, and 1 (1.1%) developed in a patient with a cerebral aqueduct cyst resulting in obstructive hydrocephalus. The remaining 35 cases (39.3%) were considered spontaneous. Among all patients, the mean body mass index (BMI) was 35.3 kg/m(2), and 46.4% exhibited empty sella syndrome. Patients with spontaneous lesions were statistically significantly older (p = 0.007) and were more commonly female (p = 0.048) compared with those with nonspontaneous pathology. Additionally, those with spontaneous lesions had a greater BMI than those with nonspontaneous disease (p = 0.102), although this difference did not achieve statistical significance. Thirty-two surgeries (36.0%) involved a middle fossa craniotomy alone, whereas 57 (64.0%) involved a combined mastoid-middle fossa repair. There were 7 recurrences (7.9%); 2 patients with recurrence developed meningitis. The use of artificial titanium mesh was statistically associated with the development of recurrent CSFF (p = 0.004), postoperative wound infection (p = 0.039), and meningitis (p = 0.014). Also notable, 6 of the 7 cases with recurrence had evidence of intracranial hypertension. When the 11 cases that involved using titanium mesh were excluded, 96.2% of patients whose lesions were reconstructed with an autologous multilayer repair had neither recurrent CSFF nor meningitis at the last follow-up.
Patients with temporal bone encephalocele and CSFF commonly present with persistent otorrhea and conductive hearing loss mimicking chronic middle ear disease, which likely contributes to a delay in diagnosis. There is a high prevalence of obesity among this patient population, which may play a role in the pathogenesis of primary and recurrent disease. A middle fossa craniotomy or a combined mastoid-middle fossa approach incorporating a multilayer autologous tissue technique is a safe and reliable method of repair that may be particularly useful for large or multifocal defects. Defect reconstruction using artificial titanium mesh should generally be avoided given increased risks of recurrence and postoperative meningitis.
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