A combination of radiosurgery and soluble tissue factor enhances vascular targeting for experimental glioblastoma

Brain Cancer Treatment; A Systematic Review

Context: One of the most common aggressive and primary brain tumors is glioma. The majority of diagnoses are referred to high-grade malignant glioblastoma, which carries the worst prognosis. Still, treatment of brain tumors remains a big challenge for clinicians. This study was designed to investigate the efficacy of gene therapy in the treatment of brain cancer. Methods: Studies use genes as a therapeutic agent in brain cancer treatment even alone or in combination with other treatment methods. Full-text papers, which met the inclusion criteria, were independently assessed by two reviewers. Disagreements were resolved by consultation with a third reviewer. Results: Statistical analysis showed that 50% of the papers used a virus, 36% used polymers, and 14% used cells as carriers to transfect the genes as a therapeutic agent in brain tumor models. Data showed that the estimated size of the brain tumor was reduced by using co-treatment of the gene with one of the conventional therapies. Conclusions: According to the results, co-treatment of the gene with conventional therapies could be more effective than the monotherapy methods.

Targeting Tissue Factor to Tumor Vasculature to Induce Tumor Infarction

Simple Summary

Among multiple other functional roles of tissue factor (TF) and other coagulation proteins in the development and targeting of malignant disease, some scientific groups are attempting to modify TF and target the molecule or truncated forms of the molecule to tumor vasculature to selectively induce local blood vessel thromboembolic occlusion resulting in tumor infarction. This review briefly describes the characteristics and development of some of these proteins and structures, including tTF-NGR, which as the first drug candidate from this class has entered clinical trials in cancer patients.

Abstract

Besides its central functional role in coagulation, TF has been described as being operational in the development of malignancies and is currently being studied as a possible therapeutic tool against cancer. One of the avenues being explored is retargeting TF or its truncated extracellular part (tTF) to the tumor vasculature to induce tumor vessel occlusion and tumor infarction. To this end, multiple structures on tumor vascular wall cells have been studied at which tTF has been aimed via antibodies, derivatives, or as bifunctional fusion protein through targeting peptides. Among these targets were vascular adhesion molecules, oncofetal variants of fibronectin, prostate-specific membrane antigens, vascular endothelial growth factor receptors and co-receptors, integrins, fibroblast activation proteins, NG2 proteoglycan, microthrombus-associated fibrin-fibronectin, and aminopeptidase N. Targeting was also attempted toward cellular membranes within an acidic milieu or toward necrotic tumor areas. tTF-NGR, targeting tTF primarily at aminopeptidase N on angiogenic endothelial cells, was the first drug candidate from this emerging class of coaguligands translated to clinical studies in cancer patients. Upon completion of a phase I study, tTF-NGR entered randomized studies in oncology to test the therapeutic impact of this novel therapeutic modality.

LPA4-Mediated Vascular Network Formation Increases the Efficacy of Anti-PD-1 Therapy against Brain Tumors

: The structure and function of tumor blood vessels profoundly affects the tumor microenvironment. Signals mediated through the lysophosphatidic acid receptor 4 (LPA4) promote vascular network formation to restore normal vascular barrier function in subcutaneous tumors and thus improve drug delivery. However, the characteristics of the vasculature vary by organ and tumor types, and how drug delivery and leukocyte trafficking are affected by modification of vascular function by LPA in different cancers is unclear. Here, we show that LPA4 activation promotes the formation of fine vascular structures in brain tumors. RhoA/ROCK signaling contributed to LPA-induced endothelial cell-cell adhesion, and RhoA/ROCK activity following LPA4 stimulation regulated expression of VCAM-1. This resulted in increased lymphocyte infiltration into the tumor. LPA improved delivery of exogenous IgG into brain tumors and enhanced the anticancer effect of anti-programmed cell death-1 antibody therapy. These results indicate the effects of LPA on vascular structure and function apply not only to chemotherapy but also to immunotherapy. SIGNIFICANCE: These findings demonstrate that lysophosphatidic acid, a lipid mediator, promotes development of a fine capillary network in brain tumors by inducing tightening of endothelial cell-to-cell adhesion, facilitating improved drug delivery, and lymphocyte penetration.

Challenges of Using High-Dose Fractionation Radiotherapy in Combination Therapy

Radiotherapy is crucial and substantially contributes to multimodal cancer treatment. The combination of conventional fractionation radiotherapy (CFRT) and systemic therapy has been established as the standard treatment for many cancer types. With advances in linear accelerators and image-guided techniques, high-dose fractionation radiotherapy (HFRT) is increasingly introduced in cancer centers. Clinicians are currently integrating HFRT into multimodality treatment. The shift from CFRT to HFRT reveals different effects on the tumor microenvironment and responses, particularly the immune response. Furthermore, the combination of HFRT and drugs yields different results in different types of tumors or using different treatment schemes. We have reviewed clinical trials and preclinical evidence on the combination of HFRT with drugs, such as chemotherapy, targeted therapy, and immune therapy. Notably, HFRT apparently enhances tumor cell killing and antigen presentation, thus providing opportunities and challenges in treating cancer.

Notch1 and 4 signaling responds to an increasing vascular wall shear stress in a rat model of arteriovenous malformations

Notch signaling is suggested to promote the development and maintenance of cerebral arteriovenous malformations (AVMs), and an increasing wall shear stress (WSS) contributes to AVM rupture. Little is known about whether WSS impacts Notch signaling, which is important for understanding the angiogenesis of AVMs. WSS was measured in arteriovenous fistulas (AVF) surgically created in 96 rats at different time points over a period of 84 days. The expression of Notch receptors 1 and 4 and their ligands, Delta1 and 4, Jagged1, and Notch downstream gene target Hes1 was quantified in “nidus” vessels. The interaction events between Notch receptors and their ligands were quantified using proximity ligation assay. There was a positive correlation between WSS and time (r = 0.97; P < 0.001). The expression of Notch receptors and their ligands was upregulated following AVF formation. There was a positive correlation between time and the number of interactions between Notch receptors and their ligands aftre AVF formation (r = 0.62, P < 0.05) and a positive correlation between WSS and the number of interactions between Notch receptors and their ligands (r = 0.87, P < 0.005). In conclusion, an increasing WSS may contribute to the angiogenesis of AVMs by activation of Notch signaling.