Re is emerging. While TACE improves survival in selected patients, the resulting tumor hypoxia stimulates proliferation, angiogenesis, treatment resistance and metastasis, which limits its overall efficacy. Vessel normalization decreases hypoxia and improves anti-tumor immune infiltrate and drug delivery. Several pre-clinical agents aimed at normalizing tumor vasculature in HCC appear promising. Although anti-angiogenic agents with vessel normalizing potential have been trialed in advanced HCC with modest results, to date their primary intention had been to starve the tumor. Judicious use of anti-angiogenic therapies is required to achieve vessel normalization yet avoid excessive pruning of vessels. This balance, termed the normalization window, is yet uncharacterized in HCC. However, the optimal class, dose and schedule of vascular normalization agents, alone or in combination with other therapies needs to be explored further....

Alzheimer’s disease (AD) is an age-related disease, with loss of integrity of the blood–brain barrier (BBB) being an early feature. Cellular senescence is one of the reported nine hallmarks of aging. Here, we show for the first time the presence of senescent cells in the vasculature in AD patients and mouse models of AD. Senescent endothelial cells and pericytes are present in APP/PS1 transgenic mice but not in wild-type littermates at the time of amyloid deposition. In vitro, senescent endothelial cells display altered VE-cadherin expression and loss of cell junction formation and increased permeability. Consistent with this, senescent endothelial cells in APP/PS1 mice are present at areas of vascular leak that have decreased claudin-5 and VE-cadherin expression confirming BBB breakdown. Furthermore, single cell sequencing of endothelial cells from APP/PS1 transgenic mice confirms that adhesion molecule pathways are among the most highly altered pathways in these cells. At the pre-plaque stage, the vasculature shows significant signs of breakdown, with a general loss of VE-cadherin, leakage within the microcirculation, and obvious pericyte perturbation. Although senescent vascular cells were not directly observed at sites of vascular leak, senescent cells were close to the leak area. Thus, we would suggest in AD that there is a progressive induction of senescence in constituents of the neurovascular unit contributing to an increasing loss of vascular integrity. Targeting the vasculature early in AD, either with senolytics or with drugs that improve the integrity of the BBB may be valid therapeutic strategies.

T-cell infiltration of solid tumors is associated with improved prognosis and favorable responses to immunotherapy. Mechanisms that enable tumor infiltration of CD8⁺ T cells have not been defined, nor have drugs that assist this process been discovered. Here we address these issues with a focus on VE-cadherin, a major endothelial cell–specific junctional protein that controls vascular integrity. A decrease in VE-cadherin expression is associated with tumor pathology. We developed an oligonucleotide-based inhibitor (CD5-2), which disrupted the interaction of VE-cadherin with its regulator miR-27a, resulting in increased VE-cadherin expression. Administration of CD5-2 in tumor-bearing mice enhanced expression of VE-cadherin in tumor endothelium, activating TIE-2 and tight junction pathways and normalizing vessel structure and function. CD5-2 administration also enhanced tumor-specific T-cell infiltration and spatially redistributed CD8⁺ T cells within the tumor parenchyma. Finally, CD5-2 treatment enhanced the efficacy of anti-PD-1 blocking antibody. Our work establishes a role for VE-cadherin in T-cell infiltration in tumors and offers a preclinical proof of concept for CD5-2 as a therapeutic modifier of cancer immunotherapy via effects on the tumor vasculature. Cancer Res; 77(16); 4434–47. ©2017 AACR.

Cellular senescence is a mechanism to inhibit the growth of mammalian cells after oncogenic activation, or in response to damage or stress. We describe here the identification of a novel gene, SENEX, that regulates stress induced premature senescence pathways in endothelial cells (ECs) involving p16^INK4a and retinoblastoma protein activation. Endogenous levels of SENEX remain unchanged during replicative senescence but are regulated by H₂O₂-mediated stress. In contrast to that previously described for senescence in other cell types, the SENEX induced senescent ECs are profoundly anti-inflammatory. The cells are resistant to tumor necrosis factor (TNF)α–induced apoptosis, adhesion of neutrophils and mononuclear cells, and the surface (but not cytoplasmic) expression of endothelial leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1. Furthermore they are resistant to thrombin induced vascular leak. Senescent ECs such as those lining atherosclerotic lesions may therefore function to limit the inflammatory response. SENEX is also essential for EC survival since depletion either ectopically by siRNA or by high- dose H₂O₂ treatment causes apoptosis. Together, these findings expand our understanding of the role of senescence in the vasculature and identify SENEX as a fulcrum for driving the resultant phenotype of the endothelium after activation.

Rationale:: Thoracic aortic aneurysm (TAA) is a potentially lethal condition, which can affect individuals of all ages. TAA may be complicated by the sudden onset of life-threatening dissection or rupture. The underlying mechanisms leading to TAA formation, particularly in the nonsyndromal idiopathic group of patients, are not well understood. Thus, identification of new genes and targets that are involved in TAA pathogenesis are required to help prevent and reverse the disease phenotype. Objective:: Here we explore the role of ARHGAP18, a novel Rho GAP expressed by smooth muscle cells (SMCs), in the pathogenesis of TAA. Methods and Results:: Using human and mouse aortic samples, we report that ARHGAP18 levels were significantly reduced in the SMC layer of aortic aneurysms. Arhgap18 global knockout ( Arhgap18 ^{−/ −} ) mice exhibited a highly synthetic, proteolytic, and proinflammatory smooth muscle phenotype under basal conditions and when challenged with angiotensin II, developed TAA with increased frequency and severity compared with littermate controls. Chromatin immunoprecipitation studies revealed this phenotype is partly associated with strong enrichment of H3K4me3 and depletion of H3K27me3 at the MMP2 and TNF-α promoters in Arhgap18 -deficient SMC. We further show that TAA formation in the Arhgap18 ^−/− mice is associated with loss of Akt activation. The abnormal SMC phenotype observed in the Arhgap18 ^−/− mice can be partially rescued by pharmacological treatment with the mTORC1 inhibitor rapamycin, which reduces the synthetic and proinflammatory phenotype of Arhgap18 -deficient SMC. Conclusion:: We have identified ARHGAP18 as a novel protective gene against TAA formation and define an additional target for the future development of treatments to limit TAA pathogenesis.

The regulation of function of endothelial cell–cell junctions is fundamental in sustaining vascular integrity. The polycistronic microRNA (miR) complexes containing miR-23a-27a-24-2, and 23b-27b-24-1 are predicted to target the majority of major endothelial junctional proteins. We focus on miR-23a and miR-23b, and investigate the functional effects of these miRs on junctions. While miR-23a and 23b only differ by 1 nucleotide (g19) outside the seed region and thus are predicted to have the same targets, they function differently with miR-23a inhibiting permeability and miR-23b inhibiting angiogenesis. Both miRs target the junctional attractive molecule (tight junction protein 2) ZO-2 and the repulsive molecule junctional adhesion molecule C (JAM-C), although the inhibition of JAM-C by miR-23a is more profound than by miR-23b. The difference in potency is attributable to differences at g19 since a mutation of the t17, the g19 binding site of miR-23b in the 3′UTR of JAM-C restores identity. We also show that the pattern of expression of miR-23a and miR-23b and their targets are different. Thus, the paralogues miR-23a and miR-23b can have profoundly different effects on endothelial cell function due at least partially to selective effects on target proteins and differences in expression patterns of the miRs. This work exposes a hitherto unappreciated complexity in therapeutically targeting miRs.