Selective blood-brain barrier permeabilization of brain metastases by a type 1 receptor-selective tumor necrosis factor mutein

Abstract

Background Metastasis to the brain is a major challenge with poor prognosis. The blood-brain barrier (BBB) is a significant impediment to effective treatment, being intact during the early stages of tumour development and heterogeneously permeable at later stages. Intravenous injection of tumour necrosis factor (TNF) selectively induces BBB permeabilisation at sites of brain micrometastasis, in a TNF type-1 receptor (TNFR1) dependent manner. Here, to enable clinical translation, we have developed a TNFR1-selective agonist variant of human TNF that induces BBB permeabilisation, whilst minimising potential toxicity. Methods A library of human TNF muteins (mutTNF) were generated and assessed for binding specificity to mouse and human TNFR1/2, endothelial permeabilising activity in vitro, potential immunogenicity and circulatory half-life. The permeabilising ability of the most promising variant was assessed in vivo in a model of brain metastasis. Results The primary mutTNF variant showed similar affinity for human TNFR1 than wild-type human TNF, similar affinity for mouse TNFR1 as wild-type mouse TNF, undetectable binding to human/mouse TNFR2, low potential immunogenicity and permeabilisation of an endothelial monolayer. Circulatory half-life was similar to mouse/human TNF and BBB permeabilisation was induced selectively at sites of micrometastases in vivo, with a time window of ≥24h and enabling delivery of agents within a therapeutically-relevant range (0.5-150kDa), including the clinically approved therapy, trastuzumab. Conclusions We have developed a clinically-translatable mutTNF that selectively opens the BBB at micrometastatic sites, whilst leaving the rest of the cerebrovasculature intact. This approach will open a window for brain metastasis treatment that currently does not exist.

The impact of α-synuclein aggregates on blood-brain barrier integrity in the presence of neurovascular unit cells

“…The inflammation process begins with the activation of microglia in response to αSN-AGs, which results in the production of pro-inflammatory cytokines such as TNF-α [87,88]. The attenuating effects of TNF-α on the impairment of BBB have been demonstrated in several studies [89][90][91]. Furthermore, TNF-α can participate on recruitment of T cells, by enhancing integrin ligands (such as ICAM-1, VCAM-1) on endothelial cells [92], or by increasing the propensity of T cells for adhering on the brain's endothelial cells [93].…”

Repurposing synthetic and natural derivatives induces apoptosis in an orthotopic glioma‐induced xenograft model by modulating WNT/β‐catenin signaling

“…While analyzing the underlying molecular mechanisms of this quadruple-combinatorial treatment (TCNP), it is essential to clarify if the chosen drugs, both individually and as a combination, could breach the BBB, a significant impediment for GB chemotherapy [113]. This is because, though several potent chemotherapeutic agents have been developed over the past decades, systemic administration of these drugs has not provided convincing benefits in prolonging patient outcome.…”

The impact of α-synuclein aggregates on blood-brain barrier integrity in the presence of neurovascular unit cells

“…The inflammation process begins with the activation of microglia in response to αSN-AGs, which results in the production of pro-inflammatory cytokines such as TNF-α [87, 88]. The attenuating effects of TNF-α on the impairment of BBB have been demonstrated in several studies [89–91]. Furthermore, TNF-α can participate on recruitment of T cells, by enhancing integrin ligands (such as ICAM-1, VCAM-1) on endothelial cells [92], or by increasing the propensity of T cells for adhering on the brain’s endothelial cells [93].…”