Dexamethasone alleviates tumor-associated brain damage and angiogenesis

Daily glucocorticoids promote glioblastoma growth and circadian synchrony to the host

Glioblastoma (GBM) is the most common primary brain tumor in adults with a poor prognosis despite aggressive therapy. A recent, retrospective clinical study found that administering Temozolomide in the morning increased patient overall survival by 6 months compared to evening. Here, we tested the hypothesis that daily host signaling regulates tumor growth and synchronizes circadian rhythms in GBM. We found daily Dexamethasone promoted or suppressed GBM growth depending on time of day of administration and on the clock gene, Bmal1. Blocking circadian signals, like VIP or glucocorticoids, dramatically slowed GBM growth and disease progression. Finally, mouse and human GBM models have intrinsic circadian rhythms in clock gene expression in vitro and in vivo that entrain to the host through glucocorticoid signaling, regardless of tumor type or host immune status. We conclude that GBM entrains to the circadian circuit of the brain, which modulates its growth through clockcontrolled cues, like glucocorticoids.

The efficacy and safety of novel antiepileptic drugs in treatment of epilepsy of patients with brain tumors

Objective

This meta-analysis aimed to assess the effectiveness and safety of novel antiepileptic drugs (AEDs) in treating epilepsy in patients with brain tumors (BTRE).

Methods

A search was conducted on PubMed, EMBASE, Web of Science, and the Cochrane Library from inception to February 2023, with English language restriction.

Results

In this meta-analysis, 18 clinical trials involving 755 BTRE patients were included to assess the efficacy and safety of novel AEDs in BTRE treatment. At the last follow-up, a ≥50% reduction in seizure frequency was experienced by 72% of patients (random-effects model, 95% CI = 0.64-0.78) using novel AEDs. At the last follow-up, seizure freedom was experienced by 34% of patients (random-effects model, 95% CI = 0.28-0.41) using novel AEDs. The pooled incidence of AEs was found to be 19% (95% CI: 13%-26%), with a withdrawal rate due to adverse effects of only 3%. Comparable efficacy and incidence of adverse effects were observed between lacosamide and perampanel.

Conclusion

This meta-analysis suggests that novel antiepileptic drugs are deemed effective for seizure control in brain tumor patients, particularly when used as adjunctive therapy. Although lacosamide and perampanel received more focus in studies, no significant difference was observed in the efficacy and adverse reactions of these two drugs in seizure control. Further randomized controlled trials are deemed necessary to validate our findings.

Dexamethasone and overall survival and progression free survival in patients with newly diagnosed glioblastoma: a meta-analysis

PURPOSE

Glioblastomas, the most common primary malignant brain tumors in adults, still hold poor prognosis. Corticosteroids, such as dexamethasone, are usually prescribed to reduce peritumoral edema and limit neurological symptoms, although potential detrimental effects of these drugs have been described. The present meta-analysis aimed to explore the association of dexamethasone with overall survival (OS) and progression free survival (PFS) in patients with newly diagnosed glioblastoma.

METHODS

PubMed, Cochrane Library, Embase, and ClinicalTrials.gov were searched for pertinent studies following the Preferred Reporting Items of Systematic Review and Meta-Analysis checklist. Pooled multivariable-adjusted hazard ratios (HR) for OS and PFS and their associated 95% confidence intervals (CIs) were calculated using the random-effects model and the heterogeneity among studies was assessed using I2. The quality of evidence was assessed using the GRADE criteria.

RESULTS

Seven studies were included, pooling data of 1,257 patients, with age varying from 11 to 81 years. Glioblastoma patients on pre- or peri-operative dexamethasone were associated with a significantly poorer overall survival (HR: 1.33, 95% CI: 1.15, 1.55; 7 studies; I2: 59.9%) and progression free survival (HR: 1.77, 95% CI: 1.05, 2.97; 3 studies; I2: 71.1%) compared to patients not on dexamethasone. The quality of evidence was moderate for overall survival and low for progression free survival.

CONCLUSION

Dexamethasone appeared to be associated with poor survival outcomes of glioblastoma patients.

Dexamethasone Suppresses IL-33-exacerbated Malignant Phenotype of U87MG Glioblastoma Cells via NF-κB and MAPK Signaling Pathways

BACKGROUND

Interleukin (IL)-33 is highly expressed in glioblastoma (GBM) and promotes tumor progression. Targeting IL-33 may be an effective strategy for the treatment of GBM. Dexamethasone (DEX) is a controversial drug routinely used clinically in GBM therapy. Whether DEX has an effect on IL-33 is unknown. This study aimed to investigate the effect of DEX on IL-33 and the molecular mechanisms involved.

METHODS

U87MG cells were induced by tumor necrosis factor (TNF)-α to express IL-33 and then treated with DEX. The mRNA levels of IL-33, NF-κB p65, ERK1/2, and p38 were determined by real-time quantitative PCR. The expression of IL-33, IkBα (a specific inhibitor of NF-κB) and MKP-1 (a negative regulator of MAPK), as well as the phosphorylation of NF-κB, ERK1/2 and p38 MAPK, were detected by Western blotting. The secretion of IL-33 was measured by ELISA. The proliferation, migration and invasion of U87MG cells were detected by CCK8 and transwell assays, respectively.

RESULTS

DEX significantly reduced TNF-α-induced production of IL-33 in U87MG cells, which was dependent on inhibiting the activation of the NF-κB, ERK1/2 and p38 MAPK signaling pathways, and was accompanied by the increased expression of IkBα but not MKP-1. Furthermore, the proliferation, migration and invasion of U87MG cells exacerbated by IL-33 were suppressed by DEX.

CONCLUSION

DEX inhibited the production and tumor-promoting function of IL-33. Whether DEX can benefit GBM patients remains controversial. Our results suggest that GBM patients with high IL-33 expression may benefit from DEX treatment and deserve further investigation.

Perioperative dexamethasone in high-grade gliomas: the short-term benefits and long-term harms

Dexamethasone has been commonly given to patients with a presumed new GBM in relatively large doses (6-16 mg daily for 1-2 weeks) since the 1960s without any rigorous evidence. This treatment with dexamethasone before the diagnosis and adjuvant therapy makes GBM patients unique compared to other newly diagnosed cancer patients. While dexamethasone may be beneficial, recent studies suggest that this potent immunosuppressant with pleiotropic effects is harmful in the long term. This perspective article summarizes the disadvantages of perioperative dexamethasone from multiple facets. It concludes that these growing data mandate rigorously testing the benefits of using perioperative dexamethasone.

Ferroptosis and PPAR-gamma in the limelight of brain tumors and edema

Human malignant brain tumors such as gliomas are devastating due to the induction of cerebral edema and neurodegeneration. A major contributor to glioma-induced neurodegeneration has been identified as glutamate. Glutamate promotes cell growth and proliferation in variety of tumor types. Intriguently, glutamate is also an excitatory neurotransmitter and evokes neuronal cell death at high concentrations. Even though glutamate signaling at the receptor and its downstream effectors has been extensively investigated at the molecular level, there has been little insight into how glutamate enters the tumor microenvironment and impacts on metabolic equilibration until recently. Surprisingly, the 12 transmembrane spanning tranporter xCT (SLC7A11) appeared to be a major player in this process, mediating glutamate secretion and ferroptosis. Also, PPARγ is associated with ferroptosis in neurodegeneration, thereby destroying neurons and causing brain swelling. Although these data are intriguing, tumor-associated edema has so far been quoted as of vasogenic origin. Hence, glutamate and PPARγ biology in the process of glioma-induced brain swelling is conceptually challenging. By inhibiting xCT transporter or AMPA receptors in vivo, brain swelling and peritumoral alterations can be mitigated. This review sheds light on the role of glutamate in brain tumors presenting the conceptual challenge that xCT disruption causes ferroptosis activation in malignant brain tumors. Thus, interfering with glutamate takes center stage in forming the basis of a metabolic equilibration approach.

Imaging characterization of an adult H3 K27M-altered diffuse midline glioma of the medulla oblongata with a confounding steroid response

We report an uncommon, infratentorial localization of adult H3 K27M-altered diffuse midline glioma arising in a particularly rare site (medulla oblongata). In addition to this unusual presentation, the lesion exhibited a substantial contrast enhancement and size decrease after dexamethasone, generating diagnostic dilemmas. Histology, molecular details, advanced Magnetic Resonance imaging features and differential diagnoses are here described and discussed, as well as common misconceptions about steroid-sensitive mass lesions, and practical difficulties for clinicians involved in the process of making diagnosis.

In Vitro Angiogenesis Inhibition and Endothelial Cell Growth and Morphology

A co-culture assay with human umbilical vein endothelial cells (HUVECs) and normal human dermal fibroblasts (NHDFs) was used to study whether selected angiogenesis inhibitors were able to inhibit differentiation and network formation of HUVECs in vitro. The effect of the inhibitors was determined by the morphology and the calculated percentage area covered by HUVECs. Neutralizing VEGF with avastin and polyclonal goat anti-VEGF antibody and inhibiting VEGFR2 with sorafenib and vatalanib resulted in the formation of HUVEC clusters of variable sizes as a result of inhibited EC differentiation. Furthermore, numerous inhibitors of the VEGF signaling pathways were tested for their effect on the growth and differentiation of HUVECs. The effects of these inhibitors did not reveal a cluster morphology, either individually or when combined to block VEGFR2 downstream pathways. Only the addition of N-methyl-p-bromolevamisole revealed a similar morphology as when targeting VEGF and VEGFR2, meaning it may have an inhibitory influence directly on VEGFR signaling. Additionally, several nuclear receptor ligands and miscellaneous compounds that might affect EC growth and differentiation were tested, but only dexamethasone gave rise to cluster formation similarly to VEGF-neutralizing compounds. These results point to a link between angiogenesis, HUVEC differentiation and glucocorticoid receptor activation.

Glucose Influences the Response of Glioblastoma Cells to Temozolomide and Dexamethasone

Objective

Current research indicates that weakness of glucose metabolism plays an important role in silencing of invasiveness and growth of hypoxic tumors such as GBM. Moreover, there are indications that DXM, frequently used in treatment, may support GBM energy metabolism and provoke its recurrence.

Methods

We carried out in vitro experiments on the commercial T98G cell line and two primary GBM lines (HROG02, HROG17) treated with TMZ and/or DXM in physiological oxygen conditions for GBM (2.5% oxygen) and for comparison, in standard laboratory conditions (20% oxygen). The influence of different glucose levels on selected malignancy features of GBM cells-cellular viability and division, dynamic of cell culture changes, colony formation and concentration of InsR have been elevated.

Results

Under 2.5% oxygen and high glucose concentration, an attenuated cytotoxic effect of TMZ and intensification of malignancy features in all glioblastoma cell lines exposed to DXM was seen. Furthermore, preliminary retrospective analysis to assess the correlation between serum glucose levels and Ki-67 expression in surgical specimens derived from patients with GBM (IV) treated with radio-chemotherapy and prophylactic DXM therapy was performed.

Conclusion

The data suggest a link between the in vitro study results and clinical data. High glucose can influence on GBM progression through the promotion of the following parameters: cell viability, dispersal, InsR expression and cell proliferation (Ki-67). However, this problem needs more studies and explain the mechanism of action studied drugs.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.

Growth Hormone replacement therapy in pediatric brain tumor survivors

Brain tumors are the most frequent type of solid neoplasms in children with a recognized 5-year survival rate between 57 and 65%. The survival rate progressively increased in the last few years, due to the improvements in their treatment based on chemotherapy, radiotherapy, and surgery. At the same time, at long term follow-up, clinicians should carefully evaluate comorbidities and long term sequelae secondary to the disease and its treatment. Growth Hormone Deficiency (GHD) is an endocrinopathy commonly found among pediatric cancer survivors, with a negative effect on the child's final height and entire metabolism. GH replacement therapy (GHRT), with a synthetic hormone analog, may improve the growth rate and finally adult height, ameliorating the quality of life after cancer treatment. However, in clinical practice, GHRT is adopted with caution for fear of cancer recurrence or the onset of second malignancies. In our review, we perform a focus on the GH structure and function, comparing benefits and risks of GHRT, derived from the analysis of the data currently available in the literature.

Novel Insights into the Role of the Mineralocorticoid Receptor in Human Glioblastoma

The majority of glioblastoma (GBM) patients require the administration of dexamethasone (DEXA) to reduce brain inflammation. DEXA activates the glucocorticoid receptor (GR), which can consequently crosstalk with the mineralocorticoid receptor (MR). However, while GR signaling is well studied in GBM, little is known about the MR in brain tumors. We examined the implication of the MR in GBM considering its interplay with DEXA. Together with gene expression studies in patient cohorts, we used human GBM cell lines and patient-derived glioma stem cells (GSCs) to assess the impact of MR activation and inhibition on cell proliferation, response to radiotherapy, and self-renewal capacity. We show that in glioma patients, MR expression inversely correlates with tumor grade. Furthermore, low MR expression correlates with poorer survival in low grade glioma while in GBM the same applies to classical and mesenchymal subtypes, but not proneural tumors. MR activation by aldosterone suppresses the growth of some GBM cell lines and GSC self-renewal. In GBM cells, the MR antagonist spironolactone (SPI) can promote proliferation, radioprotection and cooperate with DEXA. In summary, we propose that MR signaling is anti-proliferative in GBM cells and blocks the self-renewal of GSCs. Contrary to previous evidence obtained in other cancer types, our results suggest that SPI has no compelling anti-neoplastic potential in GBM.

The Effects of Administrated Dexamethasone on Neurologic Assessment in Neuro-oncology Scale in Patients with Intracranial Tumors

BACKGROUND: In intracranial tumors, glucocorticoids are the main therapy to treat peritumoral edema. Neurologic Assessment in Neuro-Oncology (NANO) score is an instrument that can assess neurological function objectively and practically in patients with intracranial tumors. AIM: This study aims to determine the effect of dexamethasone administration on the NANO score of intracranial tumor patients. METHODS: This study was a pre-experimental study with a pre and post-test design at the H. Adam Malik General Hospital in Medan from March to September 2020. The study population was intracranial tumor patients. The research subject were 37 subjects taken consecutively. Treated with dexamethasone injection, then examined the NANO score before and after receiving dexamethasone injection on days 1, 2, and 3. Statistical analysis with Friedman test. RESULTS: Based on the demographic characteristics of the research subjects, the mean age was 53.29 ± 8.5 years. Most of the research subjects were male (54.1%) while female (45.9%). Most types of intracranial tumors were secondary tumors (59.5%) while primary tumors (40.5%). The significant effect of dexamethasone on NANO score in patients with intracranial tumors (p < 0.001). CONCLUSION: There is an effect of dexamethasone on the NANO score of patients with intracranial tumors.

Critical Review of Biodegradable and Bioactive Polymer Composites for Bone Tissue Engineering and Drug Delivery Applications

In the determination of the bioavailability of drugs administered orally, the drugs' solubility and permeability play a crucial role. For absorption of drug molecules and production of a pharmacological response, solubility is an important parameter that defines the concentration of the drug in systemic circulation. It is a challenging task to improve the oral bioavailability of drugs that have poor water solubility. Most drug molecules are either poorly soluble or insoluble in aqueous environments. Polymer nanocomposites are combinations of two or more different materials that possess unique characteristics and are fused together with sufficient energy in such a manner that the resultant material will have the best properties of both materials. These polymeric materials (biodegradable and other naturally bioactive polymers) are comprised of nanosized particles in a composition of other materials. A systematic search was carried out on Web of Science and SCOPUS using different keywords, and 485 records were found. After the screening and eligibility process, 88 journal articles were found to be eligible, and hence selected to be reviewed and analyzed. Biocompatible and biodegradable materials have emerged in the manufacture of therapeutic and pharmacologic devices, such as impermanent implantation and 3D scaffolds for tissue regeneration and biomedical applications. Substantial effort has been made in the usage of bio-based polymers for potential pharmacologic and biomedical purposes, including targeted deliveries and drug carriers for regulated drug release. These implementations necessitate unique physicochemical and pharmacokinetic, microbiological, metabolic, and degradation characteristics of the materials in order to provide prolific therapeutic treatments. As a result, a broadly diverse spectrum of natural or artificially synthesized polymers capable of enzymatic hydrolysis, hydrolyzing, or enzyme decomposition are being explored for biomedical purposes. This summary examines the contemporary status of biodegradable naturally and synthetically derived polymers for biomedical fields, such as tissue engineering, regenerative medicine, bioengineering, targeted drug discovery and delivery, implantation, and wound repair and healing. This review presents an insight into a number of the commonly used tissue engineering applications, including drug delivery carrier systems, demonstrated in the recent findings. Due to the inherent remarkable properties of biodegradable and bioactive polymers, such as their antimicrobial, antitumor, anti-inflammatory, and anticancer activities, certain materials have gained significant interest in recent years. These systems are also actively being researched to improve therapeutic activity and mitigate adverse consequences. In this article, we also present the main drug delivery systems reported in the literature and the main methods available to impregnate the polymeric scaffolds with drugs, their properties, and their respective benefits for tissue engineering.

An efficient and novel treatment regimen including temozolomide for medulloblastoma: a case study

Background:

The central nervous system (CNS) embryonal tumour is a rare malignancy reported in adults and more commonly in children. The most available treatments may cause neurological dysfunctions requiring clinical attention.

Case presented:

A 29-year-old male was referred with ataxia and diplopia, and brain imaging revealed a posterior fossa lesion suggesting medulloblastoma. The tumour and related symptoms were notably alleviated following treatment with dexamethasone. Following the recurrence of tumour, a biopsy and pathology report, the diagnosis of desmoplastic/nodular medulloblastoma was confirmed. The patient underwent 18 fractions of 180 cGy spine and whole-brain radiation therapy (RT). In addition, 5400 cGy irradiation in 12 fractions was given to the posterior fossa together with 2 mg/m2 intravenous vincristine (VCR) weekly over 6 weeks. Following a 3-week break, the patient was scheduled to receive 150 mg/m2/day temozolomide for 5 days, 2 mg VCR and 65 mg/m2/day cisplatin every 3 weeks for 8 cycles.

Conclusion:

The patient gained survival benefit to date (60 months since diagnosis) with favourable life quality. The promising response in this one exemplary case study proposes that a combined chemotherapy regimen including temozolomide, vincristine and cisplatin is an effective treatment choice for CNS embryonal tumours following RT; however, the further evaluation and a randomised clinical trial are needed.

Enhancing the Therapeutic Efficacy of Gefitinib in Human Non-Small-Cell Lung Cancer through Drug Combination

The interaction between tumor cells and the tumor microenvironment (TME) significantly influences tumorigenesis, so TME-targeted therapy has attracted widespread attention. We have previously demonstrated that the combination of dipyridamole, bestatin, and dexamethasone (DBD mix, DBDx) is effective against heterogeneous human pancreatic cancer and hepatocellular carcinoma in mouse xenograft models. To further expand the therapeutic potential of this drug combination, herein, we investigated the antitumor efficacy and the underlying mechanism of DBDx and the combination of DBDx and gefitinib in different mouse xenograft models of human non-small-cell lung cancer (NSCLC). Three human cancer cell lines H460, PG, and A431 were used to determine the apoptosis and growth inhibition induced by DBDx, gefitinib, and their combinations. Changes in epidermal growth factor receptor (EGFR) signaling pathway-related proteins were analyzed following treatment using western blotting. In vitro, DBDx strongly inhibited the proliferation of tumor cells, whereas the combined treatment exhibited a significant synergistic effect. Compared with DBDx, the combination treatment further induced apoptosis and downregulated the expression of molecules associated with EGFR signaling pathway. In vivo, compared with DBDx alone, the combination treatment distinctly inhibited tumor growth in mouse xenograft models of human NSCLC. Overall, our results indicate that the combination of DBDx and gefitinib in the treatment of human NSCLC is very promising, which warrants further translational studies.

In Vitro Studies of Prednisolone Loaded PLGA Nanoparticles-Surface Functionalized With Folic Acid on Glioma and Macrophage Cell Lines

Background: Glucocorticoids are employed for their anti-inflammatory effects in treatingglioma, whose cells are known to overexpress the folate receptors. Some glucocorticoids haveshown inhibitory effects, but the efficacy of prednisolone when delivered via folate receptormediateduptake, has not been attempted. The study aimed to assess the efficacy of targeteddelivery of prednisolone on glioma cell lines like C6 and U87 via the folate receptors. Methods: Targeted delivery of prednisolone was achieved by initially conjugating folic acid (FA)to the di-block copolymer of polylactic acid (PLA) – polyethylene glycol (PEG). This moietycarrying di-block copolymer was incorporated on the surface of the drug-loaded poly lactic-coglycolicacid (PLGA) nanoparticle (NP) by employing the Interfacial Activity Assisted SurfaceFunctionalization (IAASF) technique. The NPs were evaluated for size, zeta potential, and drugloading. It was characterized using particle size analyser, SEM, 1H-NMR, and XRD. cell uptake,cytotoxicity, and anti-inflammatory activities were studied for various formulations. Results: The cytotoxicity assay indicated a high cell growth inhibitory effect of drug encapsulatedNPs with FA moiety as compared to free drug and NPs without the moiety for an incubationperiod of three, five, and six days. The growth-inhibitory effect of the free drug was short-lived,whereas FA functionalized NPs showed higher uptake and sustained inhibitory effect, and werealso able to significantly control the release of pro-inflammatory cytokines like tumour necrosisfactor-alpha (TNF-α) and nitric oxide (NO). Conclusion: Uptake, attenuation of pro-inflammatory signals, and the inhibitory effect ofprednisolone on the cells were more effective when targeted with the FA moiety on the surfaceof NPs as compared to free drug and NPs without the moiety.

Pharmacokinetic Principles and Their Application to Central Nervous System Tumors

Despite increasing knowledge of the biologic drivers of central nervous system tumors, most targeted agents trialed to date have not shown activity against these tumors in clinical trials. To effectively treat central nervous system tumors, an active drug must achieve and maintain an effective exposure at the tumor site for a long enough period of time to exert its intended effect. However, this is difficult to assess and achieve due to the constraints of drug delivery to the central nervous system. To address this complex problem, an understanding of pharmacokinetic principles is necessary. Pharmacokinetics is classically described as the quantitative study of drug absorption, distribution, metabolism, and elimination. The innate chemical properties of a drug, its administration (dose, route and schedule), and host factors all influence these four key pharmacokinetic phases. The central nervous system adds a level of complexity to standard plasma pharmacokinetics as it is a coupled drug compartment. This review will discuss special considerations of pharmacokinetics in the context of therapeutic development for central nervous system tumors.

Tetrahydrocurcumin mitigates acute hypobaric hypoxia-induced cerebral oedema and inflammation through the NF-κB/VEGF/MMP-9 pathway

High-altitude cerebral oedema (HACE) is a potentially fatal manifestation of high-altitude sickness and is caused partly by inflammation and the blood-brain barrier disruption. Tetrahydrocurcumin (THC) has been reported to exert effective antioxidative and anti-inflammatory effects; This study sought to elucidate the underlying mechanism of THC in mitigating HACE using a mouse model. Our results revealed that prophylactic administration of THC (40 mg/kg) for 3 days significantly alleviated the increase in brain water content (BWC), interleukin-1β (IL-1β) and TNF-α levels caused by acute hypobaric hypoxia (AHH). Additionally, superoxide dismutase (SOD) activity was increased by THC to enhance the ability to resist hypoxia. Histological and ultrastructural analysis of the cerebrum revealed that THC administration mitigated AHH-induced pericellular oedema and reduced the perivascular space, resulting in the simultaneous remission of oedema and protection of mitochondria in the cerebrum. In vitro, astrocytes exposed to hypoxia (4% O₂ ) for 24 hr exhibited and increase in IL-1β expression followed by an increase in vascular endothelial growth factor (VEGF) levels. Furthermore, THC administration remarkably downregulated VEGF, matrix metallopeptidase-9 (MMP-9), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, both in vivo and in vitro. Our data highlight the potential prophylactic activity of THC in HACE, it effectively mitigates AHH-induced cerebral oedema and inflammation is associated with the inhibition of the NF-κB/ VEGF/MMP-9 pathways.

DBDx-based drug combinations show highly potent therapeutic efficacy against human pancreatic cancer xenografts in athymic mice

Previous studies have shown that DBDx, a combination consisting of dipyridamole, bestatin and dexamethasone is highly effective against several cancer xenografts in athymic mice. Here the therapeutic effects of DBDx and its combination with gemcitabine or capcitabine against human pancreatic cancer xenografts and the mechanism were studied. In vivo experiments performed in athymic mice showed that the antitumor efficacy of DBDx was much stronger than that of gemcitabine or capecitabine alone. Notably, the combination of DBDx and gemcitabine or capcitabine further enhanced the efficacy. In the case of DBDx (242 mg/kg) plus gemcitabine (100 mg/kg), tumor weight decreased about 97.7%, and tumor sizes were shrinking during the treatment. In the case of DBDx (242 mg/kg) plus capecitabine (718.7 mg/kg), tumor weight decreased about 94.9%. Moreover, DBDx and its combinations obviously prolonged theoverall survival of mice compared with gemcitabine or capcitabine alone. DBDx-based drug combination therapy showed no obvious systematic toxicity. The gene expression profile analysis showed that the genes changed by DBDx were related to immune system and tumor vasculature. The result of protein array showed that the changed proteins in the serum of treated mice were related to immune and inflammation system. These results show that DBDx-based drug combinations, a new strategy which integrates the use of low-cytotoxic drugs and cytotoxic chemotherapeutics, are highly effective regimens against human pancreatic cancer in athymic mice at well tolerated doses. DBDx-based drug combination therapy might provide new options for the treatment of pancreatic cancer.

Teaching an Old Drug New Tricks: Dexamethasone as an In Vivo Inhibitor of Glioblastoma Dispersal

Identifying drugs that can mitigate dispersal of glioblastoma cells, particularly after patients undergo radiotherapy and concomitant chemotherapy, may increase the length of time to recurrence and improve overall survival. Previous studies have shown that dexamethasone (Dex), a drug currently used to treat brain tumor-related edema, which is tapered immediately after the edema has resolved, induces fibronectin matrix assembly (FNMA) and reduces dispersal of primary human glioblastoma multiforme (GBM) cells in vitro and ex vivo. Here, we utilized an in vivo mouse retina dispersal assay to demonstrate that Dex also inhibits dispersal in vivo. We show that 1) Dex significantly reduces z-axis penetration of glioblastoma cells into mouse retina; 2) treatment alters the morphology of dispersal; 3) without Dex, the presence of fibronectin increases dispersal; 4) treatment activates in vivo FNMA by glioblastoma cells, leading to the containment of the tumor mass; and 5) Dex-mediated activation of FNMA is fibronectin dose-dependent. Dispersal inhibition could be achieved at human equivalent doses as low as 1 mg/day, a dose significantly lower than currently used to reduce edema. This is the first step towards future studies in which patients can be potentially maintained on low-dose dexamethasone therapy with the aim of increasing the time between initial resection and recurrence.

Retinal angiographic alteration in diabetic macular edema after dexamethasone implantation: a case report

Here we reported a rare case of the implantation of a dexamethasone intravitreal implant (DEX) in which decreased retinal vessel density (VD) was found by optical coherence tomography angiography (OCTA). A 74-year-old male with diabetes mellitus presented with bilateral macular edema. The best-corrected visual acuity (BCVA) was 0.6 in the right eye. Diabetic macular edema (DME) was diagnosed. A DEX for the right eye was planned, and the preoperative evaluation showed a superficial VD of 48.74 percent, a deep VD of 53.12 percent, and a foveal avascular zone (FAZ) 0.165 mm² in size by OCTA. The BCVA in the right eye recovered to 0.8, and a notably lower superficial VD of 45.97 percent and a deep VD of 45.40 percent were observed with an enlarged FAZ of 0.294 mm² one month postoperatively. Moreover, BCVA in the right eye was maintained at 0.8, while further reductions in both superficial (40.07 percent) and deep (40.91 percent) VD were noted with a FAZ measured at 0.305 mm² two months postoperatively. In conclusion, retinal superficial and deep VD decreased, while the FAZ increased, after the implantation of the DEX in a patient with DME.

Controversial roles for dexamethasone in glioblastoma - Opportunities for novel vascular targeting therapies

Glioblastoma is a highly aggressive and treatment resistant primary brain tumor. Features of glioblastoma include peritumoral cerebral edema, the major contributor to neurological impairment. Although the current clinical approach to edema management is administration of the synthetic corticoid dexamethasone, increasing evidence indicates numerous adverse effects of dexamethasone on glioblastoma burden at the molecular, cellular and clinical level. The contradictions of dexamethasone for glioblastoma and brain metastasis therapy are discussed in this article. Finally, alternative strategies for cerebrovascular edema therapy with vascular stabilizing, anti-permeability agents that are either approved or in clinical trials for diabetic retinopathy and macula edema, are addressed.

Glucocorticoid-mediated effects on angiogenesis in solid tumors

Angiogenesis is essential in tumor development to maintain the oxygen and nutrient supply. Glucocorticoids have shown both direct and indirect angiostatic properties in various types of solid cancers. In most of the reported cases glucocorticoid-mediated actions involved suppression of multiple pro-angiogenic factors expression by cancer cells. The anti-angiogenic properties of glucocorticoids correlated with diminished tumor vasculature and reduced tumor growth in multiple in vivo studies. However, when glucocorticoid treatment is considered, possible adverse events should be taken into account. Additional research is needed to further test the use of these steroidal drugs in cancer therapy.

Dexamethasone in Glioblastoma Multiforme Therapy: Mechanisms and Controversies

Glioblastoma multiforme (GBM) is the most common and malignant of the glial tumors. The world-wide estimates of new cases and deaths annually are remarkable, making GBM a crucial public health issue. Despite the combination of radical surgery, radio and chemotherapy prognosis is extremely poor (median survival is approximately 1 year). Thus, current therapeutic interventions are highly unsatisfactory. For many years, GBM-induced brain oedema and inflammation have been widely treated with dexamethasone (DEX), a synthetic glucocorticoid (GC). A number of studies have reported that DEX also inhibits GBM cell proliferation and migration. Nevertheless, recent controversial results provided by different laboratories have challenged the widely accepted dogma concerning DEX therapy for GBM. Here, we have reviewed the main clinical features and genetic and epigenetic abnormalities underlying GBM. Finally, we analyzed current notions and concerns related to DEX effects on cerebral oedema, cancer cell proliferation and migration and clinical outcome.

Progesterone Is More Effective Than Dexamethasone in Prolonging Overall Survival and Preserving Neurologic Function in Experimental Animals with Orthotopic Glioblastoma Allografts

OBJECTIVE

Dexamethasone (DEXA) has been widely used in the management of peritumoral brain edema. DEXA, however, has many systemic side effects and can interact negatively with glioma therapy. Progesterone (PROG), however, is a well-tolerated and readily accessible anti-inflammatory and antiedema agent, with potent neuroprotective properties. We investigated whether PROG could serve as a viable alternative to DEXA in the management of peritumoral brain edema.

METHODS

We used an orthotopic C6 glioblastoma model with male Sprague-Dawley rats. Tumor grafts were allowed to grow for 14 days before drug treatment with DEXA 1 mg/kg, PROG 10 mg/kg, or PROG 20 mg/kg for 5 consecutive days. The overall animal survival and neurologic function were evaluated. Mechanistic studies on blood-brain barrier permeability and angiogenic responses were performed on the ex vivo tumor grafts.

RESULTS

We found that all drug treatments prolonged overall survival to different extents. PROG 10 mg led to significantly longer survival and better preservation of neurologic function and body weight. The blood-brain barrier permeability was better preserved with PROG 10 mg than with DEXA, possibly through downregulation of matrix metalloproteinase-9 and aquaporin-4 expression. Antiangiogenic responses were also observed in the PROG group.

CONCLUSIONS

The present proof-of-concept pilot study has provided novel information on the use of PROG as a corticosteroid-sparing agent in brain tumor management. Further translational and clinical studies are warranted.

A Reduced Exogenous Steroid Taper for Postoperative Brain Tumor Patients-A Case-Control Study

BACKGROUND

Dexamethasone is a standard treatment for cerebral edema after brain tumor surgery. However, its side effects can negatively impact the quality and safety of care provided to patients. Sparse evidence exists in the literature regarding postoperative steroid dosing to guide clinicians. The objective of this study was to determine if a new reduced exogenous steroid taper (REST) protocol would effectively treat postoperative cerebral edema while reducing the incidence of steroid-related side effects including diabetes, hypertension, and insomnia.

METHODS

A REST protocol (dexamethasone 38.5 mg tapered over 10 days) was instituted for patients with postoperative brain tumor of a single surgeon. Historical controls treated with a high-dose taper (dexamethasone 117 mg taper over 17 days) were selected to match for baseline characteristics. Outcomes of new or worsened diabetes, hypertension, and insomnia, as well as length of stay (LOS) and 30-day readmission rates, were compared.

RESULTS

Twenty-five patients were included in each group. There were no significant differences in baseline characteristics. The REST group received a median of 34.5 mg (interquartile range, 32-41 mg) of dexamethasone, whereas controls received 43 mg (interquartile range, 16-91 mg) (P = 0.04). There was a significant reduction in the incidence of new or worsened hypertension in the REST group (0%) compared with controls (20%, P = 0.02). No difference was seen in the rates of diabetes mellitus, insomnia, LOS, or 30-day readmission rates.

CONCLUSIONS

A reduced steroid taper after brain tumor surgery significantly reduced the incidence of hypertension without increasing LOS or 30-day readmissions compared with controls treated with a high-dose taper.

Conventional Anti-glioblastoma Chemotherapy Affects Proteoglycan Composition of Brain Extracellular Matrix in Rat Experimental Model in vivo

Temozolomide (TMZ) is a conventional chemotherapy drug for adjuvant treatment of glioblastoma multiforme (GBM), often accompanied by dexamethasone (DXM) to prevent brain oedema and alleviate clinical side effects. Here, we aimed to investigate an ability of the drugs to affect normal brain tissue in terms of proteoglycan (PG) composition/content in experimental rat model in vivo. Age- and brain zone-specific transcriptional patterns of PGs were demonstrated for 8, 60, and 120 days old rats, and syndecan-1, glypican-1, decorin, biglycan, and lumican were identified as the most expressed PGs. DXM treatment affected both PG core proteins expression (mainly syndecan-1, glypican-1, decorin, biglycan, lumican, versican, brevican, and NG2) and heparan sulphate (HS)/chondroitin sulphate (CS) content in organotypic brain slice culture ex vivo and experimental animals in vivo in a dose-dependent manner. TMZ treatment did not result in the significant changes in PG core proteins expression both in normal rat brain hippocampus and cortex in vivo (although generics did), but demonstrated significant effects onto polysaccharide HS/CS content in the brain tissue. The effects were age- and brain zone-specific and similar with the age-related PGs expression changes in rat brain. Combination of TMZ with DXM resulted in the most profound deterioration in PGs composition and content in the brain tissue both at core protein and glycosaminoglycan levels. Taken together, the obtained results demonstrate that conventional anti-glioblastoma therapy affects proteoglycan structure and composition in normal brain tissue, potentially resulting in deterioration of brain extracellular matrix and formation of the favourable tumorigenic niche for the expansion of the residual glioma cells. During the TMZ chemotherapy, dose and regimen of DXM treatment matter, and repetitive low DXM doses seem to be more sparing treatment compared with high DXM dose(s), which should be avoided where possible, especially in combination with TMZ.

Glucocorticoids as an adjunct to oncologic treatment in solid malignancies - Not an innocent bystander

Glucocorticoids are steroidal hormones which exert their action via genomic and non-genomic mechanisms. In the clinical setting, glucocorticoids are utilized for their anti-inflammatory, anti-allergenic and immunomodulatory effects and for their well-established, pro-apoptotic effects on hematological malignancies. In the treatment of solid tumors, glucocorticoids serve primarily for alleviation of tumor- and treatment-related symptoms and in most cases are not considered to have a direct effect on tumor growth and spread. However, significant pre-clinical data suggest that glucocorticoids have diverse effects on tumor progression, both pro- and anti- tumorigenic. In contrast, the clinical data regarding the pro- and anti-tumorigenic effects of glucocorticoids on solid tumors is scarce, and summarized in this review. The following review presents the suggested glucocorticoids mechanism of action and the effects of glucocorticoids on tumor cells, on the tumor microenvironment and on tumor response to cytotoxic therapy, in the pre-clinical and clinical settings.

The evaluation of the effects of steroid treatment on the tumor and peritumoral edema by DWI and MR spectroscopy in brain tumors

OBJECTIVE

To investigate the effects of dexamethasone on brain tumor and peritumoral edema by different sequences of magnetic resonance imaging (MRI).

MATERIALS AND METHODS

MRI was performed in 28 patients with brain tumor. Patients were divided into the 3 groups based on the histological diagnosis; Group I: high-grade glial tumor, Group II: low-grade glial tumor, and Group III: brain metastasis. The measurements of peritumoral edema volume and apparent diffusion coefficient (ADC) values were performed while the peak areas of cerebral metabolites were measured by spectroscopy in groups I and II. The changes in edema volumes, ADC values and cholin/creatine peak areas were compared.

RESULTS

The volume of peritumoral edema was decreased in groups I and II, but increased in group III after dexamethasone treatment. These changes were not statistically significant for 3 groups. ADC value was decreased in group I and increased in groups II and III. Changes in ADC values were statistically significant. Cholin/creatine peak areas were decreased after dexamethasone in groups I and II, but these changes were also not significant.

CONCLUSION

Dexamethasone has no significant effect on the volume of peritumoral edema in glial tumor and metastasis. Moreover, dexamethasone increases the fluid movements in low grade gliomas and metastases, decreases in high grade gliomas. However, more comprehensive clinical studies are needed to show the effects of dexamethasone on brain tumors and peritumoral edema.

Temozolomide toxicity operates in a xCT/SLC7a11 dependent manner and is fostered by ferroptosis

The glutamate exchanger xCT (SLC7a11) is causally linked with the malignancy grade of brain tumors and represents a key player in glutamate, cystine and glutathione metabolism. Although blocking xCT is not cytotoxic for brain tumors, xCT inhibition disrupts the neurodegenerative and microenvironment-toxifying activity of gliomas. Here, we report on the use of various xCT inhibitors as single modal drugs and in combination with the autophagy-inducing standard chemotherapeutic agent temozolomide (Temodal/Temcad®, TMZ). xCT overexpressing cells (xCT^OE) are more resistant to the FDA and EMA approved drug sulfasalazine (Azulfidine/Salazopyrin/Sulazine®, SAS) and RNAi-mediated xCT knock down (xCT^KD) in gliomas increases the susceptibility towards SAS in rodent gliomas. In human gliomas, challenged xCT expression had no impact on SAS-induced cytotoxicity. Noteworthy, other xCT inhibitors such as erastin and sorafenib showed enhanced efficacy on xCT^KD gliomas. In contrast, cytotoxic action of TMZ operates independently from xCT expression levels on rodent gliomas. Human glioma cells with silenced xCT expression display higher vulnerability towards TMZ alone as well as towards combined TMZ and SAS. Hence, we tested the partial xCT blockers and ferroptosis inducing agents erastin and sorafenib (Nexavar®, FDA and EMA-approved drug for lung cancer). Noteworthy, xCT^OE gliomas withstand erastin and sorafenib-induced cell death in a concentration-dependent manner, whereas siRNA-mediated xCT knock down increased susceptibility towards erastin and sorafenib. TMZ efficacy can be potentiated when combined with erastin, however not by sorafenib. Moreover, gliomas with high xCT expression are more vulnerable towards combinatorial treatment with erastin-temozolomide. These results disclose that ferroptosis inducers are valid compounds for potentiating the frontline therapeutic agent temozolomide in a multitoxic approach.

ATF4 promotes angiogenesis and neuronal cell death and confers ferroptosis in a xCT-dependent manner

Activating transcription factor 4 (ATF4) is a critical mediator of metabolic and oxidative homeostasis and cell survival. ATF4 is elevated in response to diverse microenvironmental stresses, including starvation, ER stress damages and exposure to toxic factors. Here we show that ATF4 expression fosters the malignancy of primary brain tumors (WHO grade III and IV gliomas) and increases proliferation and tumor angiogenesis. Hence, ATF4 expression promotes cell migration and anchorage-independent cell growth, whereas siRNA-mediated knockdown of ATF4 attenuates these features of malignancy in human gliomas. Further experiments revealed that ATF4-dependent tumor promoting effects are mediated by transcriptional targeting the glutamate antiporter xCT/SCL7A11 (also known as system Xc^-). Thus, xCT is elevated as a consequence of ATF4 activation. We further found evidence that ATF4-induced proliferation can be attenuated by pharmacological or genetic xCT inhibition and ferroptosis inducers such as sorafenib, erastin and GPx4 inhibitor RSL3. Further, fostered xCT expression promotes cell survival and growth in ATF4 knockdown cells. Moreover, increased xCT levels ameliorate sorafenib and erastin-induced ferroptosis. Conversely, ATF4 knockdown renders cells susceptible for erastin, sorafenib and RSL3-induced ferroptosis. We further identified that ATF4 promotes tumor-mediated neuronal cell death which can be alleviated by xCT inhibition. Moreover, elevated ATF4 expression in gliomas promotes tumor angiogenesis. Noteworthy, ATF4-induced angiogenesis could be diminished by ferroptosis inducers erastin and by GPx4 inhibitor RSL3. Our data provide proof-of-principle evidence that ATF4 fosters proliferation and induces a toxic microenvironmental niche. Furthermore, ATF4 increases tumor angiogenesis and shapes the vascular architecture in a xCT-dependent manner. Thus, inhibition of ATF4 is a valid target for diminishing tumor growth and vasculature via sensitizing tumor cells for ferroptosis.

Dexamethasone Downregulates Endothelin Receptors and Reduces Endothelin-Induced Production of Matrix Metalloproteinases in Cultured Rat Astrocytes

In brain disorders, astrocytes change phenotype to reactive astrocytes and are involved in the induction of neuroinflammation and brain edema. The administration of glucocorticoids (GCs), such as dexamethasone (Dex), reduces astrocytic activation, but the mechanisms underlying this inhibitory action are not well understood. Endothelins (ETs) promote astrocytic activation. Therefore, the effects of Dex on ET receptor expressions were examined in cultured rat astrocytes. Treatment with 300 nM Dex for 6-48 hours reduced the mRNA expression of astrocytic ET_A and ET_B receptors to 30-40% of nontreated cells. Levels of ET_A and ET_B receptor proteins became about 50% of nontreated cells after Dex treatment. Astrocytic ET_A and ET_B receptor mRNAs were decreased by 300 nM hydrocortisone. The effects of Dex and hydrocortisone on astrocytic ET receptors were abolished in the presence of mifepristone, a GC receptor antagonist. Although Dex did not decrease the basal levels of matrix metalloproteinase (MMP) 3 and MMP9 mRNAs, pretreatment with Dex reduced ET-induced increases in MMP mRNAs. The effects of ET-1 on the release of MMP3 and MMP9 proteins were attenuated by pretreatment with Dex. ET-1 stimulated the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in cultured astrocytes. Pretreatment with Dex reduced the ET-induced increases in ERK1/2 phosphorylation. In contrast, pretreatment with Dex did not affect MMP production or ERK1/2 phosphorylation induced by phorbol myristate acetate, a protein kinase C activator. These results indicate that Dex downregulates astrocytic ET receptors and reduces ET-induced MMP production.

NLRC5/CITA: A Key Player in Cancer Immune Surveillance

Cancer cells need to escape immune surveillance for successful tumor growth. Loss of MHC class I has been described as a major immune evasion strategy in many cancers. MHC class I transactivator (CITA), NLRC5 [nucleotide-binding domain and leucine-rich repeats containing (NLR) family, caspase activation and recruitment domain (CARD) domain containing 5], is a key transcription coactivator of MHC class I genes. Recent genetic studies have revealed that NLRC5 is a major target for cancer immune evasion mechanisms. The reduced expression or activity of NLRC5 caused by promoter methylation, copy number loss, or somatic mutations is associated with defective MHC class I expression, impaired cytotoxic T cell activation, and poor patient prognosis. Here, we review the role of NLRC5 in cancer immune evasion and the future prospects for cancer research.

Simulating vasogenic brain edema using chronic VEGF infusion

OBJECTIVE To study peritumoral brain edema (PTBE), it is necessary to create a model that accurately simulates vasogenic brain edema (VBE) without introducing a complicated tumor environment. PTBE associated with brain tumors is predominantly a result of vascular endothelial growth factor (VEGF) secreted by brain tumors, and VEGF infusion alone can lead to histological blood-brain barrier (BBB) breakdown in the absence of tumor. VBE is intimately linked to BBB breakdown. The authors sought to establish a model for VBE with chronic infusion of VEGF that can be validated by serial in-vivo MRI and histological findings. METHODS Male Fischer rats (n = 182) underwent stereotactic striatal implantation of MRI-safe brain cannulas for chronic infusion of VEGF (2-20 µg/ml). Following a preinfusion phase (4-6 days), the rats were exposed to VEGF or control rat serum albumin (1.5 µl/hr) for as long as 144 hours. Serial MRI was performed during infusion on a high-field (9.4-T) machine at 12-24, 24-36, 48-72, and 120-144 hours. Rat brains were then collected and histological analysis was performed. RESULTS Control animals and animals infused with 2 µg/ml of VEGF experienced no neurological deficits, seizure activity, or abnormal behavior. Animals treated with VEGF demonstrated a significantly larger volume (42.90 ± 3.842 mm³) of T2 hyper-attenuation at 144 hours when compared with the volume (8.585 ± 1.664 mm³) in control animals (mean difference 34.31 ± 4.187 mm³, p < 0.0001, 95% CI 25.74-42.89 mm³). Postcontrast T1 enhancement in the juxtacanalicular region indicating BBB breakdown was observed in rats undergoing infusion with VEGF. At the later time periods (120-144 hrs) the volume of T1 enhancement (34.97 ± 8.99 mm³) was significantly less compared with the region of edema (p < 0.0001). Histologically, no evidence of necrosis or inflammation was observed with VEGF or control infusion. Immunohistochemical analysis demonstrated astrocyte activation, vascular remodeling, and increased claudin-5 expression in juxtacanalicular regions. Aquaporin-4 expression was increased in both control and VEGF animals in the juxtacanalicular regions. CONCLUSIONS The results of this study show that chronic brain infusion of VEGF creates a reliable model of VBE. This model lacks necrosis and inflammation that are characteristic of previous models of VBE. The model allows for a precise investigation into the mechanism of VBE formation. The authors also anticipate that this model will allow for investigation into the mechanism of glucocorticoid action in abrogating VBE, and to test novel therapeutic strategies targeting PTBE.

A versatile ex vivo technique for assaying tumor angiogenesis and microglia in the brain

Primary brain tumors are hallmarked for their destructive activity on the microenvironment and vasculature. However, solely few experimental techniques exist to access the tumor microenvironment under anatomical intact conditions with remaining cellular and extracellular composition. Here, we detail an ex vivo vascular glioma impact method (VOGIM) to investigate the influence of gliomas and chemotherapeutics on the tumor microenvironment and angiogenesis under conditions that closely resemble the in vivo situation. We generated organotypic brain slice cultures from rats and transgenic mice and implanted glioma cells expressing fluorescent reporter proteins. In the VOGIM, tumor-induced vessels presented the whole range of vascular pathologies and tumor zones as found in human primary brain tumor specimens. In contrast, non-transformed cells such as primary astrocytes do not alter the vessel architecture. Vascular characteristics with vessel branching, junctions and vessel meshes are quantitatively assessable as well as the peritumoral zone. In particular, the VOGIM resembles the brain tumor microenvironment with alterations of neurons, microglia and cell survival. Hence, this method allows live cell monitoring of virtually any fluorescence-reporter expressing cell. We further analyzed the vasculature and microglia under the influence of tumor cells and chemotherapeutics such as Temozolamide (Temodal/Temcad®). Noteworthy, temozolomide normalized vasculare junctions and branches as well as microglial distribution in tumor-implanted brains. Moreover, VOGIM can be facilitated for implementing the 3Rs in experimentations. In summary, the VOGIM represents a versatile and robust technique which allows the assessment of the brain tumor microenvironment with parameters such as angiogenesis, neuronal cell death and microglial activity at the morphological and quantitative level.

Management of the Pediatric Neurocritical Care Patient

Pediatric neurocritical care is a growing subspecialty of pediatric intensive care that focuses on the management of acute neurological diseases in children. A brief history of the field of pediatric neurocritical care is provided. Neuromonitoring strategies for children are reviewed. Management of major categories of acute childhood central neurologic diseases are reviewed, including treatment of diseases associated with intracranial hypertension, seizures and status epilepticus, stroke, central nervous system infection and inflammation, and hypoxic-ischemic injury.

Glucocorticoids in the management of peritumoral brain edema: a review of molecular mechanisms

Peritumoral brain edema (PTBE) is mediated by blood-brain barrier breakdown. PTBE results from interstitial vasogenic brain edema due to vascular endothelial growth factor and other inflammatory products of brain tumors. Glucocorticoids (GCs) are the mainstay for treatment of PTBE despite significant systemic side effects. GCs are thought to affect multiple cell types in the edematous brain. Here, we review preclinical studies of GC effects on edematous brain and review mechanisms underlying GC action on tumor cells, endothelial cells, and astrocytes. GCs may reduce tumor cell viability and suppress vascular endothelial growth factor (VEGF) production in tumor cells. Modulation of expression and distribution of tight junction proteins occludin, claudin-5, and ZO-1 in endothelial cells likely plays a central role in GC action on endothelial cells. GCs may also have an effect on astrocyte angiopoietin production and limited effect on astrocyte aquaporin. A better understanding of these molecular mechanisms may lead to the development of novel therapeutics for management of PTBE with a better side effect profile.

NLRC5/MHC class I transactivator is a target for immune evasion in cancer

Cancer cells develop under immune surveillance, thus necessitating immune escape for successful growth. Loss of MHC class I expression provides a key immune evasion strategy in many cancers, although the molecular mechanisms remain elusive. MHC class I transactivator (CITA), known as "NLRC5" [NOD-like receptor (NLR) family, caspase recruitment (CARD) domain containing 5], has recently been identified as a critical transcriptional coactivator of MHC class I gene expression. Here we show that the MHC class I transactivation pathway mediated by CITA/NLRC5 constitutes a target for cancer immune evasion. In all the 21 tumor types we examined, NLRC5 expression was highly correlated with the expression of MHC class I, with cytotoxic T-cell markers, and with genes in the MHC class I antigen-presentation pathway, including LMP2/LMP7, TAP1, and β2-microglobulin. Epigenetic and genetic alterations in cancers, including promoter methylation, copy number loss, and somatic mutations, were most prevalent in NLRC5 among all MHC class I-related genes and were associated with the impaired expression of components of the MHC class I pathway. Strikingly, NLRC5 expression was significantly associated with the activation of CD8(+) cytotoxic T cells and patient survival in multiple cancer types. Thus, NLRC5 constitutes a novel prognostic biomarker and potential therapeutic target of cancers.

The anti-angiogenic effect of dexamethasone in a murine hepatocellular carcinoma model by augmentation of gluconeogenesis pathway in malignant cells

PURPOSE

Angiogenesis is a long-term complex process involving various protein factors in hepatocellular carcinoma (HCC). Dexamethasone (Dex), considered as a synthetic glucocorticoid drug in clinical therapy, has been reported to have the therapeutic efficacy against liver cancer by intervention of abnormal glycolysis. In this study, we investigated the anti-angiogenic effect of Dex in murine liver cancer and attempted to demonstrate the potential mechanism.

METHODS

The malignant cells H22 were treated with Dex. Western blotting was used to explore the expression of PEPCK and G6Pase which were the two key enzymes that regulated gluconeogenesis. The supernatants from cultured H22 treated by Dex were collected and co-cultured with HUVECs. In vitro, migration assay, transwell assay and tube formation assay were performed to assess for migration, proliferation and tube formation abilities of HUVECs, respectively. In situ murine hepatoma model with green fluorescent protein markers (HepG2-GFP) was constructed to determine angiogenesis after treatment by Dex.

RESULTS

PEPCK and G6Pase were almost deficient in H22 compared with normal liver cells NCTC-1469 (P < 0.01). After treated by Dex, the gluconeogenesis could be restored significantly (P < 0.01) in H22 cells. The supernatant of H22 treated by Dex inhibited the migration, tube formation and endothelial permeability in HUVECs (P < 0.05). In mouse tissue, PEPCK and G6Pase were highly expressed in Dex group than control groups (P < 0.01). 11β-HSDs abnormally expressed in tumor also could be restored by Dex. Meanwhile, the density and total length of microvessels in Dex-treated group were less than those in HCC groups (P < 0.05).

CONCLUSIONS

This study explored the therapeutic efficacy of Dex in murine HCC. Dex might inhibit tumor growth and angiogenesis by augmenting the gluconeogenesis pathway.

Effects of different bronchoalveolar lavage methods on tracheobronchial foreign body patients

OBJECTIVES/HYPOTHESIS

To compare the different effects of bronchoalveolar lavage (BAL) with diverse combinations of lidocaine, epinephrine, and dexamethasone on pediatric patients with an inhaled tracheobronchial foreign body (TFB).

STUDY DESIGN

Randomized controlled study.

METHODS

Two hundred forty cases of pediatric patients with inhaled TFB were included in this study, and were randomly divided into four groups using three kinds of drugs for BAL, namely 0.9% saline (S) group, 2% lidocaine with diluted epinephrine (LE) group, 2% lidocaine with diluted epinephrine and 0.5% dexamethasone (LED), control group (C) without BAL. The incidences of intraoperative or postoperative complications and recovery periods were compared. Meanwhile, the concentrations of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in BAL fluids and plasma were evaluated by enzyme-linked immunosorbent assay.

RESULTS

The incidences of bronchospasm, hypoxemia, and postoperative fever were significantly lower in the LED group than other groups (P < .001). Fever after the TFB removal procedure appeared later in the LED group than the other groups. The improvement and healing periods in the LE and LED groups were significantly shorter than those in the C and S groups (P < .001). The concentrations of IL-1β, IL-6, and TNF-α in BAL fluids were significantly higher in the LE and LED groups than those in the S group (P < .001), but those in the plasma of the C and S groups were lower compared with the LE and LED groups (P < .001).

CONCLUSIONS

BAL with lidocaine, epinephrine, and dexamethasone could promote recovery for TFB patients and reduce incidences of complications, possibly by regulating release of proinflammatory cytokines.

LEVEL OF EVIDENCE

1b.

Sunitinib impedes brain tumor progression and reduces tumor-induced neurodegeneration in the microenvironment

Malignant gliomas can be counted to the most devastating tumors in humans. Novel therapies do not achieve significant prolonged survival rates. The cancer cells have an impact on the surrounding vital tissue and form tumor zones, which make up the tumor microenvironment. We investigated the effects of sunitinib, a small molecule multitargeted receptor tyrosine kinase inhibitor, on constituents of the tumor microenvironment such as gliomas, astrocytes, endothelial cells, and neurons. Sunitinib has a known anti-angiogenic effect. We found that sunitinib normalizes the aberrant tumor-derived vasculature and reduces tumor vessel pathologies (i.e. auto-loops). Sunitinib has only minor effects on the normal, physiological, non-proliferating vasculature. We found that neurons and astrocytes are protected by sunitinib against glutamate-induced cell death, whereas sunitinib acts as a toxin towards proliferating endothelial cells and tumor vessels. Moreover, sunitinib is effective in inducing glioma cell death. We determined the underlying pathways by which sunitinib operates as a toxin on gliomas and found vascular endothelial growth factor receptor 2 (VEGFR2, KDR/Flk1) as the main target to execute gliomatoxicity. The apoptosis-inducing effect of sunitinib can be mimicked by inhibition of VEGFR2. Knockdown of VEGFR2 can, in part, foster the resistance of glioma cells to receptor tyrosine kinase inhibitors. Furthermore, sunitinib alleviates tumor-induced neurodegeneration. Hence, we tested whether temozolomide treatment could be potentiated by sunitinib application. Here we show that sunitinib can amplify the effects of temozolomide in glioma cells. Thus, our data indicate that combined treatment with temozolomide does not abrogate the effects of sunitinib. In conclusion, we found that sunitinib acts as a gliomatoxic agent and at the same time carries out neuroprotective effects, reducing tumor-induced neurodegeneration. Thus, this report uncovered sunitinib's actions on the brain tumor microenvironment, revealing novel aspects for adjuvant approaches and new clinical assessment criteria when applied to brain tumor patients.

A multifunctional drug combination shows highly potent therapeutic efficacy against human cancer xenografts in athymic mice

The tumor microenvironment plays a crucial role during tumor development. Integrated combination of drugs that target tumor microenvironment is a promising approach to anticancer therapy. Here, we report a multifunctional combination of low-cytotoxic drugs composed of dipyridamole, bestatin and dexamethasone (DBDx) which mainly acts on the tumor microenvironment shows highly potent antitumor efficacy in vivo. In mouse hepatoma H22 model, the triple drug combination showed synergistic and highly potent antitumor efficacy. The combination indices of various combinations of the triple drugs were between 0.2 and 0.5. DBDx inhibited the growth of a panel of human tumor xenografts and showed no obvious systemic toxicity. At tolerated doses, DBDx suppressed the growth of human hepatocellular carcinoma BEL-7402, HepG2, and lung adenocarcinoma A549 xenografts by 94.5%, 93.7% and 96.9%, respectively. Clonogenic assay demonstrated that DBDx showed weak cytotoxicity. Western blot showed that Flk1 and Nos3 were down-regulated in the DBDx-treated group. Proteomic analysis showed that DBDx mainly affected the metabolic process and immune system process; in addition, the angiogenesis and VEGF signaling pathway were also affected. Conclusively, DBDx, a multifunctional drug combination of three low-cytotoxic drugs, shows synergistic and highly potent antitumor efficacy evidently mediated by the modulation of tumor microenvironment. Based on its low-cytotoxic attributes and its broad-spectrum antitumor therapeutic efficacy, this multifunctional combination might be useful in the treatment of cancers, especially those refractory to conventional chemotherapeutics.

Gliomas and the vascular fragility of the blood brain barrier

Astrocytes, members of the glial family, interact through the exchange of soluble factors or by directly contacting neurons and other brain cells, such as microglia and endothelial cells. Astrocytic projections interact with vessels and act as additional elements of the Blood Brain Barrier (BBB). By mechanisms not fully understood, astrocytes can undergo oncogenic transformation and give rise to gliomas. The tumors take advantage of the BBB to ensure survival and continuous growth. A glioma can develop into a very aggressive tumor, the glioblastoma (GBM), characterized by a highly heterogeneous cell population (including tumor stem cells), extensive proliferation and migration. Nevertheless, gliomas can also give rise to slow growing tumors and in both cases, the afflux of blood, via BBB is crucial. Glioma cells migrate to different regions of the brain guided by the extension of blood vessels, colonizing the healthy adjacent tissue. In the clinical context, GBM can lead to tumor-derived seizures, which represent a challenge to patients and clinicians, since drugs used for its treatment must be able to cross the BBB. Uncontrolled and fast growth also leads to the disruption of the chimeric and fragile vessels in the tumor mass resulting in peritumoral edema. Although hormonal therapy is currently used to control the edema, it is not always efficient. In this review we comment the points cited above, considering the importance of the BBB and the concerns that arise when this barrier is affected.

Corticosteroid use in neuro-oncology: an update

Because of the lack of curative approaches for most patients with malignant brain tumors, supportive therapy, which aims at maintaining quality of life and functional independence, has a central role in the treatment of many patients. Steroids are particularly important in the setting of supportive therapy. They are commonly used to treat tumor-associated edema, and their administration is typically associated with rapid symptom relief, such as the resolution of headaches. Besides their antiedema activity, corticosteroids are characterized by their potent antilymphoma properties and their effects against acute or delayed emesis caused by systemic chemotherapy in cancer patients. Accordingly, steroids are among the most frequently used drugs in oncology. These desirable properties of steroids are counterbalanced by cardiovascular, muscular, and psychiatric side effects. On the cellular level, corticosteroids exert various effects that translate into the desired clinical activity, but they also evoke significant toxicity that may outweigh the beneficial effects. The mode of action and the limitations of steroid treatment are summarized in this review article. Interactions between steroids and other drugs must be considered. A particular challenge to the ongoing use of glucocorticoids is that newer therapeutic approaches are being introduced in neuro-oncology for which concomitant steroids are likely to be contraindicated. These include the emergence of various immunotherapeutic approaches including vaccination strategies and treatment with immune checkpoint inhibitors. Since the administration of steroids may interfere with the activity of these novel therapies, an even more critical evaluation of their use will be required.

Interleukin-13 receptor alpha 2-targeted glioblastoma immunotherapy

Glioblastoma (GBM) is the most lethal primary brain tumor, and despite several refinements in its multimodal management, generally has very poor prognosis. Targeted immunotherapy is an emerging field of research that shows great promise in the treatment of GBM. One of the most extensively studied targets is the interleukin-13 receptor alpha chain variant 2 (IL13Rα2). Its selective expression on GBM, discovered almost two decades ago, has been a target for therapy ever since. Immunotherapeutic strategies have been developed targeting IL13Rα2, including monoclonal antibodies as well as cell-based strategies such as IL13Rα2-pulsed dendritic cells and IL13Rα2-targeted chimeric antigen receptor-expressing T cells. Advanced therapeutic development has led to the completion of several clinical trials with promising outcomes. In this review, we will discuss the recent advances in the IL13Rα2-targeted immunotherapy and evaluate the most promising strategy for targeted GBM immunotherapy.

The impact of dietary isoflavonoids on malignant brain tumors

Poor prognosis and limited therapeutic options render malignant brain tumors one of the most devastating diseases in clinical medicine. Current treatment strategies attempt to expand the therapeutic repertoire through the use of multimodal treatment regimens. It is here that dietary fibers have been recently recognized as a supportive natural therapy in augmenting the body's response to tumor growth. Here, we investigated the impact of isoflavonoids on primary brain tumor cells. First, we treated glioma cell lines and primary astrocytes with various isoflavonoids and phytoestrogens. Cell viability in a dose-dependent manner was measured for biochanin A (BCA), genistein (GST), and secoisolariciresinol diglucoside (SDG). Dose–response action for the different isoflavonoids showed that BCA is highly effective on glioma cells and nontoxic for normal differentiated brain tissues. We further investigated BCA in ex vivo and in vivo experimentations. Organotypic brain slice cultures were performed and treated with BCA. For in vivo experiments, BCA was intraperitoneal injected in tumor-implanted Fisher rats. Tumor size and edema were measured and quantified by magnetic resonance imaging (MRI) scans. In vascular organotypic glioma brain slice cultures (VOGIM) we found that BCA operates antiangiogenic and neuroprotective. In vivo MRI scans demonstrated that administered BCA as a monotherapy was effective in reducing significantly tumor-induced brain edema and showed a trend for prolonged survival. Our results revealed that dietary isoflavonoids, in particular BCA, execute toxicity toward glioma cells, antiangiogenic, and coevally neuroprotective properties, and therefore augment the range of state-of-the-art multimodal treatment approach.