scholarly journals Blood–Brain Barrier in Brain Tumors: Biology and Clinical Relevance

2021 ◽  
Vol 22 (23) ◽  
pp. 12654
Author(s):  
Francesca Mo ◽  
Alessia Pellerino ◽  
Riccardo Soffietti ◽  
Roberta Rudà
Keyword(s):  
Brain Tumors ◽  
Blood Brain Barrier ◽  
Kinase Inhibitors ◽  
Checkpoint Inhibitors ◽  
Small Cell Lung Carcinoma ◽  
Phase 1 ◽  
Brain Barrier ◽  
Convection Enhanced Delivery ◽  
Cell Lung Carcinoma ◽  
Blood Brain

The presence of barriers, such as the blood–brain barrier (BBB) and brain–tumor barrier (BTB), limits the penetration of antineoplastic drugs into the brain, resulting in poor response to treatments. Many techniques have been developed to overcome the presence of these barriers, including direct injections of substances by intranasal or intrathecal routes, chemical modification of drugs or constituents of BBB, inhibition of efflux pumps, physical disruption of BBB by radiofrequency electromagnetic radiation (EMP), laser-induced thermal therapy (LITT), focused ultrasounds (FUS) combined with microbubbles and convection enhanced delivery (CED). However, most of these strategies have been tested only in preclinical models or in phase 1–2 trials, and none of them have been approved for treatment of brain tumors yet. Concerning the treatment of brain metastases, many molecules have been developed in the last years with a better penetration across BBB (new generation tyrosine kinase inhibitors like osimertinib for non-small-cell lung carcinoma and neratinib/tucatinib for breast cancer), resulting in better progression-free survival and overall survival compared to older molecules. Promising studies concerning neural stem cells, CAR-T (chimeric antigen receptors) strategies and immunotherapy with checkpoint inhibitors are ongoing.

scholarly journals Oncolytic Viruses for Malignant Glioma: On the Verge of Success?

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1294
Author(s):  
Yogesh R. Suryawanshi ◽  
Autumn J. Schulze
Keyword(s):  
Immune Responses ◽  
Malignant Glioma ◽  
Blood Brain Barrier ◽  
Tumor Heterogeneity ◽  
Checkpoint Inhibitors ◽  
Oncolytic Viruses ◽  
Brain Barrier ◽  
Current Status ◽  
Blood Brain ◽  
Federal Authority

Glioblastoma is one of the most difficult tumor types to treat with conventional therapy options like tumor debulking and chemo- and radiotherapy. Immunotherapeutic agents like oncolytic viruses, immune checkpoint inhibitors, and chimeric antigen receptor T cells have revolutionized cancer therapy, but their success in glioblastoma remains limited and further optimization of immunotherapies is needed. Several oncolytic viruses have demonstrated the ability to infect tumors and trigger anti-tumor immune responses in malignant glioma patients. Leading the pack, oncolytic herpesvirus, first in its class, awaits an approval for treating malignant glioma from MHLW, the federal authority of Japan. Nevertheless, some major hurdles like the blood–brain barrier, the immunosuppressive tumor microenvironment, and tumor heterogeneity can engender suboptimal efficacy in malignant glioma. In this review, we discuss the current status of malignant glioma therapies with a focus on oncolytic viruses in clinical trials. Furthermore, we discuss the obstacles faced by oncolytic viruses in malignant glioma patients and strategies that are being used to overcome these limitations to (1) optimize delivery of oncolytic viruses beyond the blood–brain barrier; (2) trigger inflammatory immune responses in and around tumors; and (3) use multimodal therapies in combination to tackle tumor heterogeneity, with an end goal of optimizing the therapeutic outcome of oncolytic virotherapy.

scholarly journals Principles and Current Clinical Landscape of Multispecific Antibodies against Cancer

2021 ◽  
Vol 22 (11) ◽  
pp. 5632
Author(s):  
Mariam Elshiaty ◽  
Hannah Schindler ◽  
Petros Christopoulos
Keyword(s):  
Kinase Inhibitors ◽  
Small Cell Lung Carcinoma ◽  
Phase 1 ◽  
Survival Rates ◽  
Cell Receptor ◽  
Therapeutic Success ◽  
Cell Lung Carcinoma ◽  
Anticancer Efficacy ◽  
Cell Therapies ◽  
Recent Phase

Building upon the resounding therapeutic success of monoclonal antibodies, and supported by accelerating progress in engineering methods, the field of multispecific therapeutic antibodies is growing rapidly. Over 140 different molecules are currently in clinical testing, with excellent results in recent phase 1–3 clinical trials for several of them. Multivalent bispecific IgG-modified formats predominate today, with a clear tendency for more target antigens and further increased valency in newer constructs. The strategies to augment anticancer efficacy are currently equally divided between disruption of multiple surface antigens, and additional redirection of cytotoxic T or NK lymphocytes against the tumor. Both effects complement other modern modalities, such as tyrosine kinase inhibitors and adoptive cell therapies, with which multispecifics are increasingly applied in combination or merged, for example, in the form of antibody producing CAR-T cells and oncolytics. While mainly focused on B-cell malignancies early on, the contemporary multispecific antibody sector accommodates twice as many trials against solid compared to hematologic cancers. An exciting emerging prospect is the targeting of intracellular neoantigens using T-cell receptor (TCR) fusion proteins or TCR-mimic antibody fragments. Considering the fact that introduction of PD-(L)1 inhibitors only a few years ago has already facilitated 5-year survival rates of 30–50% for per se highly lethal neoplasms, such as metastatic melanoma and non-small-cell lung carcinoma, the upcoming enforcement of current treatments with “next-generation” immunotherapeutics, offers a justified hope for the cure of some advanced cancers in the near future.

Hyperosmolar blood-brain barrier disruption in baboons: an in vivo study using positron emission tomography and rubidium-82

1996 ◽  
Vol 84 (3) ◽  
pp. 494-502 ◽  
Author(s):  
Bernhard Zünkeler ◽  
Richard E. Carson ◽  
Jeffrey Olson ◽  
Ronald G. Blasberg ◽  
Mary Girton ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Brain Tumors ◽  
Blood Brain Barrier ◽  
Emission Tomography ◽  
Brain Barrier ◽  
Blood Brain ◽  
Positron Emission ◽  
The Mean ◽  
Rubidium 82

✓ Hyperosmolar blood-brain barrier (BBB) disruption remains controversial as an adjuvant therapy to increase delivery of water-soluble compounds to extracellular space in the brain in patients with malignant brain tumors. To understand the physiological effects of BBB disruption more clearly, the authors used positron emission tomography (PET) to study the time course of BBB permeability in response to the potassium analog rubidium-82 (82Rb, halflife 75 seconds) following BBB disruption in anesthetized adult baboons. Mannitol (25%) was injected into the carotid artery and PET scans were performed before and serially at 8- to 15-minute intervals after BBB disruption. The mean influx constant (K1), a measure of permeability-surface area product, in ipsilateral, mannitol-perfused mixed gray- and white-matter brain regions was 4.9 ± 2.4 µl/min/ml (± standard deviation) at baseline and increased more than 100% (ΔK1 = 9.4 ± 5.1 µl/min/ml, 18 baboons) in brain perfused by mannitol. The effect of BBB disruption on K1 correlated directly with the total amount of mannitol administered (p < 0.005). Vascular permeability returned to baseline with a halftime of 24.0 ± 14.3 minutes. The mean brain plasma volume rose by 0.57 ± 0.34 ml/100 ml in ipsilateral perfused brain following BBB disruption. This work provides a basis for the in vivo study of permeability changes induced by BBB disruption in human brain and brain tumors.

Quantification and pharmacokinetics of blood-brain barrier disruption in humans

1996 ◽  
Vol 85 (6) ◽  
pp. 1056-1065 ◽  
Author(s):  
Bernhard Zünkeler ◽  
Richard E. Carson ◽  
Jeff Olson ◽  
Ronald G. Blasberg ◽  
Hetty Devroom ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Normal Brain ◽  
Content Type ◽  
Barrier Disruption ◽  
Blood Brain Barrier Disruption ◽  
Blood Brain ◽  
Brain Barrier Disruption ◽  
Fine Print

✓ Hyperosmolar blood-brain barrier disruption (HBBBD), produced by infusion of mannitol into the cerebral arteries, has been used in the treatment of brain tumors to increase drug delivery to tumor and adjacent brain. However, the efficacy of HBBBD in brain tumor therapy has been controversial. The goal of this study was to measure changes in vascular permeability after HBBBD in patients with malignant brain tumors. The permeability (K1) of tumor and normal brain blood vessels was measured using rubidium-82 and positron emission tomography before and repeatedly at 8- to 15-minute intervals after HBBBD. Eighteen studies were performed in 13 patients, eight with glioblastoma multiforme and five with anaplastic astrocytoma. The HBBBD increased K1 in all patients. Baseline K1 values were 2.1 ± 1.4 and 34.1 ± 22.1 µl/minute/ml (± standard deviation) for brain and tumor, respectively. The peak absolute increases in K1 following HBBBD were 20.8 ± 11.7 and 19.7 ± 10.7 µl/minute/ml for brain and tumor, corresponding to percentage increases of approximately 1000% in brain and approximately 60% in tumor. The halftimes for return of K1 to near baseline for brain and tumor were 8.1 ± 3.8 and 4.2 ± 1.2 minutes, respectively. Simulations of the effects of HBBBD made using a very simple model with intraarterial methotrexate, which is exemplary of drugs with low permeability, indicate that 1) total exposure of the brain and tumor to methotrexate, as measured by the methotrexate concentration-time integral (or area under the curve), would increase with decreasing infusion duration and would be enhanced by 130% to 200% and by 7% to 16%, respectively, compared to intraarterial infusion of methotrexate alone; and 2) exposure time at concentrations above 1 µM, the minimal concentration required for the effects of methotrexate, would not be enhanced in tumor and would be enhanced by only 10% in brain. Hyperosmolar blood-brain barrier disruption transiently increases delivery of water-soluble compounds to normal brain and brain tumors. Most of the enhancement of exposure results from trapping the drug within the blood-brain barrier, an effect of the very transient alteration of the blood-brain barrier by HBBBD. Delivery is most effective when a drug is administered within 5 to 10 minutes after disruption. However, the increased exposure and exposure time that occur with methotrexate, the permeability of which is among the lowest of the agents currently used clinically, are limited and the disproportionate increase in brain exposure, compared to tumor exposure, may alter the therapeutic index of many drugs.

Blood–Brain Barrier and Edema in Brain Tumors

Brain Edema ◽  
2017 ◽  
pp. 293-313 ◽  
Author(s):  
Andreas F. Mack ◽  
Hartwig Wolburg ◽  
Petra Fallier-Becker
Keyword(s):  
Brain Tumors ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Blood Brain
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