Abstract
Whole brain radiation therapy (WBRT) to primary central nervous system lymphoma (PCNSL) correlate with brain atrophy and leukoencephalopathy on serial computed tomography or MRI scans, ...negatively impacting cognitive function and quality of life. We retrospectively evaluated 53 patients with histologically proven PCNSL who underwent cerebrospinal fluid (CSF) examination including β2-MG, sIL2R, CXCL13, and IL-10 preoperatively. All patients were newly diagnosed and followed up every 3 months from the day they were discharged from the hospital. Follow up period is at least 1 year from last day of chemotherapy. Clinical data included patient demographics, radiological and characteristics; whole brain volume (mm2) calculated from BainLabTM automatically, Global Cortical Atrophy (GCA) for global brain atrophy, Medial Temporal Atrophy (MTA) for temporal atrophy, and Fazekas scale for white matter lesions. The unpaired t test and multivariable liner regression were used to examine the clinical, CSF and radiological characteristics of patients. The mean age at symptom onset was 65.2 years (47-85 years). Thirty three of 53 (62%) patients underwent WBRT with chemotherapy (WBRT group). In all patients, multivariable analysis revealed WBRT correlate with brain volume reduction (p=0.0005) and progression of temporal lobe atrophy (p=0.0056). In addition, Age correlated with increasing white matter lesions at 1 year after chemotherapy (p=0.0422). In WBRT group, multivariable analysis indicated that high CSF IL-10 level accelerated brain volume reduction (p=0.0122) and temporal lobe atrophy (p=0.0343) at 6 months after chemotherapy. However, there were no significant factor for influencing brain atrophy at 1 year. Higher IL-10 ( > 100mg/ml) level demonstrated higher brain atrophy rate (p=0.0366) and severe temporal atrophy at 1 year (p=0.0214). In elderly patients with high preoperative CSF IL-10 levels, cerebral atrophy and toxic leukoencephalopathy may progress in short period of time after WBRT. We should consider treatment strategy that avoid WBRT, such as R-MPV chemotherapy, for PCNSL patients.
Abstract
Cranial irradiation (IR) is a cornerstone in the treatment of high-grade pediatric brain tumors. While lifesaving, it is associated with severe sequalae in 50-90 % of the survivors, as they ...often show disabling cognitive dysfunction, declined IQ, impaired processing speed, anxiety and posttraumatic stress symptoms, resulting in poorer academic accomplishments and social isolation. Memantine (Mem) is a non-competitive NMDA receptor antagonist and a potent enhancer of neural plasticity. While an improvement in cognition in post-IR cancer survivors and in synaptic plasticity in association to hippocampal neurogenesis have been documented, the exact mechanisms underlying Mem’s actions are poorly understood. The goal of this project is to further dissect the actions of Mem and identify factors that contribute to hippocampal neurogenesis. To this end, 20-day-old C57BL6/J mice were subjected to a single dose of 7 Gy whole brain irradiation and then supplied with Mem in the drinking water (10 mg/kg/day) to obtain a steady-state plasma concentration of the drug. Two weeks after IR, Sholl analysis of the morphology of the newborn neurons of Mem treated animals showed a statistically significant increase in coverage area (500 µm2 vs. 250 µm2, p < 0,0001) and number of dendrites (15 vs. 5, p < 0,0001) compared to non-treated individuals. Bulk-RNA sequencing analysis revealed 9 differentially expressed genes (alpha=0.1) between the hippocampal cell populations of Mem and vehicle-treated IR mice, which are related to protein folding and the programmed cell death machinery. At six weeks after IR, Mem treatment maintains the gamma oscillatory dynamics in the hippocampal CA3 region (~2x10-9 V2 in non-IR, ~1x109 V2 in IR), but with no apparent recovery to the sham levels. These results emphasize the strong neurogenic effect that Mem exerts on the surviving newborn neurons, while also highlighting Mem’s low toxicity and impact on the normal function of the brain.
Abstract
Most advanced-stage non-small cell lung cancer (NSCLC) patients have brain metastases that render a dismal prognosis. Treatment of metastatic brain lesions from NSCLC and other tumor types ...include radiation as part of a multimodal treatment regimen. Challenges in the application of radiotherapy include overcoming radiation resistance and reducing associated co-morbidities. Non-toxic therapeutics capable of sensitizing tumors to radiation are needed to improve survival and mitigate radiation side-effects. Many CNS and solid systemic tumors express ligand-gated ion channels, which may contribute to tumor growth. Leveraging ion channels is therefore a potential way of diminishing the spread of cancer. We find that NSCLC and its brain metastases express subunits of the type-A GABA-gated chloride channel or GABAA receptor. Importantly, patient-derived NSCLC cells have functional GABAA receptors. We identified a brain penetrant, small molecule activator of GABAA receptors (AMLAL-101), which alone impairs the viability of both primary NSCLC cells and brain metastatic cells. In addition, AMLAL-101 combined with radiation is a highly potent inducer of NSCLC cell death and clonogenic arrest. Using a human ex vivo model of NSCLC-on-chip, we assessed the efficacy and toxicity of AMLAL-101 relative to Docetaxel, an antimicrotubular agent used in treating advanced NSCLC. AMLAL-101 is as potent as Docetaxel but does not exhibit its toxic side effects. AMLAL-101 also potentiates radiation in vivo, significantly reducing lung adenocarcinoma xenograft tumor growth in mice, equivalent to docetaxel plus radiation. Mechanistically, AMLAL-101 activates GABAA receptors in NSCLC and synergizes with radiation by inducing an autophagic response that includes: (i) stabilization of Beclin-1, BNIP3L/NIX, and GABARAP; (ii) ATG7 upregulation; and (iii) utilization of ubiquitin-binding protein p62. Activating GABAA receptors in NSCLC and other tumor types may improve radiation efficacy and mitigate its toxic side effects in treating brain metastases.
Abstract
INTRODUCTION
Fractionated radiotherapy is a first-line treatment for glioblastoma, but daily ionizing radiation prevents durable immune infiltration of the tumor microenvironment. ...Hypofractionated radiotherapy is used to treat glioblastomas at recurrence, but the impact of hypofractionated radiotherapy on the glioblastoma immune microenvironment is incompletely understood. Here we define immune microenvironment changes across multiple immunocompetent intracranial mouse models of glioblastoma after treatment with ionizing radiation mimicking stereotactic radiosurgery (SRS) in humans.
METHODS
Syngeneic GL261 (3x105 cells/mouse) or SB28 glioblastoma cells (3x104 cells/mouse) were implanted into the frontal lobe of immunocompetent C57BL/6J mice (18 mice/arm x 4 arms). Intracranial bioluminescence was used to assess glioblastoma growth. After tumor engraftment, glioblastomas were treated with conformal SRS (18Gy/1Fx) or sham. Glioblastomas were collected for histologic, single-cell, or molecular analyses 5 days after treatment (6 mice/arm) or at the time of euthanasia after monitoring for survival (12 mice/arm). Glioblastoma immune microenvironment responses were assessed using (1) H&E, (2) single cell mass cytometry (CyTOF) or IHC to define or validate immune cell changes, respectively, or (3) multiplexed cytokine assays to elucidate molecular mechanisms reprograming the glioblastoma immune microenvironment in response to SRS.
RESULTS
SRS attenuated glioblastoma growth and prolonged survival compared to sham treatment in both immunocompetent intracranial mouse models (GL261: 14 days versus 27 days, p< 0.001, SB28: 19 days versus 22 days, p=0.001). CyTOF showed SRS decreased immunosuppressive macrophage infiltration and increased microglia or CD8+ T cell infiltration of the glioblastoma immune microenvironment. Histologic analyses validated T cell and microglia infiltration after SRS. Glioblastoma cytokine analysis revealed inhibition of pro-tumor/anti-inflammatory cytokines (IL6, LIF) after SRS.
CONCLUSIONS
Single-fraction SRS durably reprograms glioblastoma macrophage, microglia, and CD8+ T cell populations in preclinical models, suggesting SRS or inhibition of pro-tumor/anti-inflammatory mechanisms underlying the immunosuppressive glioblastoma microenvironment represent immunogenic therapies that may offer a benefit to patients with glioblastoma.
Abstract
BACKGROUND
Aside from surgery, radiotherapy (RT) remains the only standard of care treatment for meningiomas. However, few studies have identified clinical/molecular biomarkers associated ...with responsiveness to RT and the optimal timing of RT after surgery remains controversial. We aimed to assess outcomes in a large multi-institutional cohort of RT-treated meningiomas to identify clinical factors and DNA methylation and RNA expression markers associated with progression-free survival (PFS) post-RT.
METHODS
Patients with intracranial meningiomas who underwent treatment with fractionated RT between 1997-2018 were included. DNA-methylation using the Illumina 850K EPICArray and RNA-sequencing were performed on tumours with sufficient tissue. Primary endpoints were radiographic recurrence of progression and time to progression from the time of RT completion.
RESULTS
404 meningiomas were included for analysis. Of these, 167 (41.3%) recurred post-RT, usually within 5-years of RT. Previous RT to the meningioma, having a WHO grade 3 meningioma, and older age at diagnosis were independently associated with poorer PFS post-RT. Following propensity score matching, patients that received adjuvant RT had significantly better PFS post-RT compared to those that received salvage RT after recurrence (p=0.04). DNA methylation on 220 of these meningiomas segregated tumours into two distinct methylation groups (RT-resistant and RT-sensitive) based on unsupervised consensus clustering. DNA methylation were able to independently predict PFS post-RT better than all clinical factors. Differential RNA-expression analysis of these groups showed up-regulation of pathways involved in chromosome segregation and mitotic cell cycle and down-regulation of fatty acid metabolism pathways in RT-resistant meningiomas.
CONCLUSION
While there are a paucity of clinical factors that can reliably predict a meningioma’s response to RT, DNA methylation and RNA expression biomarkers may aid in differentiating RT-resistant meningiomas from RT-sensitive tumours. Patients that receive adjuvant RT may have prolonged PFS post-RT compared to those that receive salvage RT only after recurrence has already occurred.
Abstract
Glioblastoma (GBM) is the most malignant tumor that occurs within the brain and shows the dismal prognosis. The phosphoinositide 3-kinase (PI3K)-AKT signaling pathway plays a principal role ...in GBM. Also, Activated PI3K-AKT signaling by irradiation induces radioresistance. But, the pan-PI3K inhibitors cause side-effects in clinical trial. Different PI3K isoforms play non-redundant roles in brain tumor growth and regulating radioresistance. So it is expected that selective inhibition of PI3K isoforms decrease side effects. We demonstrated whether combining radiotherapy with the PI3K isoform inhibitor reduces radioresistance and tumor growth in GBM. Glioma261 expressed luciferase (GL261-luc) cell lines were used to investigate the synergistic effects of combining radiotherapy with the PI3K isoform inhibitors. GL261-luc were irradiated 1Gy with or without PI3K isoform inhibitors. GL261-luc irradiated by 1Gy was suppressed cell proliferation about 70% compared to control (p< 0.001). When irradiated with PI3K-isform inhibitor, each growth rate was about 18% (PI3K-pan, p< 0.00001), 25% (PI3K-alpha, p< 0.00001), 30% (PI3K-delta, p< 0.00001), 45% (PI3K-gamma/delta, p< 0.00001). Significant increase of DNA DSB and decrease of the migration ability were shown by combination radiotherapy with PI3K- isoform inhibitor. Especially, combining radiotherapy, PI3K-alpha inhibitor showed the effect similar to PI3K-pan inhibitor (In vitro). So, we analyzed combination therapy effects using PI3K-alphs inhibitor and radiotherapy in vivo. We demonstrated that combining radiotherapy with the PI3K-alpha isoform inhibitor markedly delayed tumor growth than radiotherapy only (p< 0.0001). Also, we confirmed that survival rate of intracranial GBM mouse was increased by combination therapy (p< 0.01). In addition, the expression of PD1, regulator of cancer immune system, in spleenocyte was increased by combination therapy (p< 0.001) (In vivo). Our results demonstrate that combining radiotherapy with the PI3K-alpha isoform improve radiosensitivity, which result in significant tumor growth delay and improved survival.
Abstract
Tumor-treating fields (TTFields) are the fourth modality of glioblastoma (GBM) treatment and in conjunction with chemotherapy can increase overall survival of GBM patients up to 60 months. ...However, in vitro and in animal models TTFields show 100% efficacy on a variety of tumor cell types including GBM cells when field strength is 4 V/cm, versus ~2 V/cm that is the clinical delivery target, TTFields are delivered transcranially. TTFields finite element modeling studies, supported by similar transcranial electric stimulation studies, show that the principal obstacle to delivering 4 V/cm is the electrically resistive skull. Our modeling shows the biophysics is more complicated than these findings. For instance, electrically-conductive cerebrospinal fluid regions surrounding the grey matter and in ventricles shunt electric current from anode to cathode, hindering delivery of the current required to produce 4 V/cm at the tumor/peritumor target. Thus, we consider two new delivery methods for TTFields. First, the transcranial array can be made more focal and directional, following modeling and development of electrode arrays used in spinal cord and deep brain stimulation. Our finite element modeling shows that similarly-designed TTFields electrode arrays can deliver field strength focally to a tumor target approaching 4 V/cm. Second, pre- or post-resection, TTFields can be delivered via electrode arrays surgically placed in the tumor or tumor resection cavity (intra-tumoral delivery), circumventing the resistive skull and CSF shunting effects. Such intra-tumoral arrays can deliver 4 V/cm to the tumor/peritumor region, opening up the potential to replicate clinically the 100% efficacy of TTFields in vitro and in animal models. Thus, new TTFields delivery may lead to unlimited survival of GMB patients via a side-effect free treatment modality.
Abstract
Their location and highly aggressive nature renders glioblastoma (GBM) among the most deadly and devastating of human malignancies. Despite extensive treatment involving surgery and adjuvant ...chemo-radiotherapy, the prognosis is still dismal and novel treatment strategies are urgently needed. Of all existing adjuvant therapies, radiotherapy contributes the most to extending the median overall survival. Increasing the efficacy of existing radiotherapeutic regimens is therefore a logical avenue to improve the survival of GBM patients. We have developed a novel radiosensitization strategy called ‘induction of mitotic enrichment’. It has long been known that the radiosensitivity of a cell depends on the phase of the cell cycle and that especially mitotic cells are especially vulnerable. Enriching the tumor for mitotic cells by arresting them during division prior to each radiotherapy fraction should therefore render the tumor population more sensitive to irradiation. Ideally, induction of mitotic enrichment should be reversible and non-cytotoxic to prevent healthy tissue toxicity and be compatible with clinically applied hyperfractionated radiotherapy regimens. We have now identified an orally available targeted tubulin polymerization inhibitor that can achieve repeated and reversible mitotic enrichment for up to 10 hours prior to radiotherapy, without causing cytotoxicity in vitro or healthy tissue toxicity in vivo. Most importantly, this tubulin inhibitor efficiently radiosensitizes a range of preclinical GBM models in vitro and in vivo, including GSC models, and significantly improves survival, but only in a mitotic enrichment setup when given 6-8 hours prior to radiotherapy to allow accumulation in mitosis. We are currently expanding our preclinical development of mitotic enrichment as a radiosensitization strategy to other mitotic targets and different intra- and extracranial cancer models representing several diseases for which radiotherapy is a mainstay treatment. In parallel, we are preparing a phase 0 trial to demonstrate induction of mitotic enrichment in human GBM.
Abstract
Treatment-related sequelae following cranial irradiation have life changing impacts for patients and their caregivers. Characterization of the basic response of human brain tissue to ...irradiation has been difficult due to a lack of preclinical models. The direct study of human brain tissue in vitro is becoming possible due to advances in stem cell biology, neuroscience, and tissue engineering with the development of organoids as novel model systems which enable experimentation with human tissue models. We sought to establish a cerebral organoid (CO) model to study the radioresponse of normal human brain tissue. COs were grown using human induced pluripotent stem cells and a modified Lancaster protocol. Compositional analysis during development of the COs showed expected populations of neurons and glia. We confirmed a population of microglia-like cells within the model positive for the makers Iba1 and CD68. After 2-months of maturation, COs were irradiated to 0, 10, and 20 Gy using a Shepard Mark-II Cs-137 irradiator and returned to culture. Subsets of COs were prepared for immunostaining at 30- and 70-days post-irradiation. To examine the effect of irradiation on the neural stem cell (NSC) population, sections were stained for SOX2 and Ki-67 expression denoting NSCs and proliferation respectively. Slides were imaged and scored using the CellProfiler software package. The percentage of proliferating NSCs 30-days post-irradiation was found to be significantly reduced for irradiated COs (5.7% (P=0.007) and 3.4% (P=0.001) for 10 and 20 Gy respectively) compared to control (12.7%). The reduction in the proliferating NSC population subsequently translated to a reduced population of NeuN-labeled mature neurons 70 days post-irradiation. The loss of proliferating NSCs and subsequent reduction in mature neurons demonstrates the long-term effects of radiation. Our initial results indicate COs will be a valuable model to study the effects of radiation therapy on normal and diseased human tissue.
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