Targeting VEGF-A to treat cancer and age-related macular degeneration

Ocular and systemic vascular endothelial growth factor ligand inhibitor use and nephrotoxicity: an update

Tumor growth is intricately linked to the process of angiogenesis, with a key role played by vascular endothelial growth factor (VEGF) and its associated signaling pathways. Notably, these pathways also play a pivotal "housekeeping" role in renal physiology. Over the past decade, the utilization of VEGF signaling inhibitors has seen a substantial rise in the treatment of diverse solid organ tumors, diabetic retinopathy, age-related macular degeneration, and various ocular diseases. However, this increased use of such agents has led to a higher frequency of encountering renal adverse effects in clinical practice. This review comprehensively addresses the incidence, pathophysiological mechanisms, and current evidence concerning renal adverse events associated with systemic and intravitreal antiangiogenic therapies targeting VEGF-A and its receptors (VEGFR) and their associated signaling pathways. Additionally, we briefly explore strategies for mitigating potential risks linked to the use of these agents and effectively managing various renal adverse events, including but not limited to hypertension, proteinuria, renal dysfunction, and electrolyte imbalances.

Metal-based nanoparticle in cancer treatment: lessons learned and challenges

Cancer, being one of the deadliest diseases, poses significant challenges despite the existence of traditional treatment approaches. This has led to a growing demand for innovative pharmaceutical agents that specifically target cancer cells for effective treatment. In recent years, the use of metal nanoparticles (NPs) as a promising alternative to conventional therapies has gained prominence in cancer research. Metal NPs exhibit unique properties that hold tremendous potential for various applications in cancer treatment. Studies have demonstrated that certain metals possess inherent or acquired anticancer capabilities through their surfaces. These properties make metal NPs an attractive focus for therapeutic development. In this review, we will investigate the applicability of several distinct classes of metal NPs for tumor targeting in cancer treatment. These classes may include gold, silver, iron oxide, and other metals with unique properties that can be exploited for therapeutic purposes. Additionally, we will provide a comprehensive summary of the risk factors associated with the therapeutic application of metal NPs. Understanding and addressing these factors will be crucial for successful clinical translation and to mitigate any potential challenges or failures in the translation of metal NP-based therapies. By exploring the therapeutic potential of metal NPs and identifying the associated risk factors, this review aims to contribute to the advancement of cancer treatment strategies. The anticipated outcome of this review is to provide valuable insights and pave the way for the advancement of effective and targeted therapies utilizing metal NPs specifically for cancer patients.

The omega-3 postbiotic trans-10-cis-15-octadecadienoic acid attenuates contact hypersensitivity in mice through downregulation of vascular endothelial growth factor A

Intestinal bacteria metabolize dietary substances to produce bioactive postbiotics, among which some are recognized for their role in promoting host health. We here explored the postbiotic potential of two omega-3 α-linolenic acid-derived metabolites: trans-10-cis-15-octadecadienoic acid (t10,c15-18:2) and cis-9-cis-15-octadecadienoic acid (c9,c15-18:2). Dietary intake of lipids rich in omega-3 α-linolenic acid elevated levels of t10,c15-18:2 and c9,c15-18:2 in the serum and feces of mice, an effect dependent on the presence of intestinal bacteria. Notably, t10,c15-18:2 mitigated skin inflammation in mice that became hypersensitive after exposure to 2,4-dinitrofluorobenzene, an experimental model for allergic contact dermatitis. In particular, t10,c15-18:2-but not c9,c15-18:2-attenuated ear swelling and edema, characteristic symptoms of contact hypersensitivity. The anti-inflammatory effects of t10,c15-18:2 were due to its ability to suppress the release of vascular endothelial growth factor A from keratinocytes, thereby mitigating the enhanced vascular permeability induced by hapten stimulation. Our study identified retinoid X receptor as a functional receptor that mediates the downregulation of skin inflammation upon treatment with t10,c15-18:2. Our results suggest that t10,c15-18:2 holds promise as an omega-3 fatty acid-derived postbiotic with potential therapeutic implications for alleviating the skin edema seen in allergic contact dermatitis-induced inflammation.

Engineering a Low-Immunogenic Mirror-Image VHH against Vascular Endothelial Growth Factor

Immunogenicity is a major caveat of protein therapeutics. In particular, the long-term administration of protein therapeutic agents leads to the generation of antidrug antibodies (ADAs), which reduce drug efficacy while eliciting adverse events. One promising solution to this issue is the use of mirror-image proteins consisting of d-amino acids, which are resistant to proteolytic degradation in immune cells. We have recently reported the chemical synthesis of the enantiomeric form of the variable domain of the antibody heavy chain (d-VHH). However, identifying mirror-image antibodies capable of binding to natural ligands remains challenging. In this study, we developed a novel screening platform to identify a d-VHH specific for vascular endothelial growth factor A (VEGF-A). We performed mirror-image screening of two newly constructed synthetic VHH libraries displayed on T7 phage and identified VHH sequences that effectively bound to the mirror-image VEGF-A target (d-VEGF-A). We subsequently synthesized a d-VHH candidate that preferentially bound the native VEGF-A (l-VEGF-A) with submicromolar affinity. Furthermore, immunization studies in mice demonstrated that this d-VHH elicited no ADAs, unlike its corresponding l-VHH. Our findings highlight the utility of this novel d-VHH screening platform in the development of protein therapeutics exhibiting both reduced immunogenicity and improved efficacy.

Arterial Adventitial Vasa Vasorum Density Reflects The Progression Of Unstable Plaques: A Retrospective Clinical Study

OBJECTIVE

Arterial adventitial vasa vasorum (AVV) plays an important role in the occurrence and development of atherosclerotic (AS) disease. AS is a systemic disease, and plaque is not only a local vascular event, but also occurs at multiple sites throughout the vascular bed. Currently, effective anti-AVV therapies are lacking. Therefore, we posed the following scientific questions: "does human carotid adventitial vasa vasorum density reflect plaque neovascularization and intimal-media hyperplasia in carotid?"; and "is it possible to reduce human AVV density by sonodynamic therapy (SDT)?"

METHODS

A retrospective study was conducted on 160 patients with carotid atherosclerosis. Duplex ultrasound scanning (DUS), contrast-enhanced ultrasound (CEUS), coronary angiography, and coronary CT angiography (CTA) were used for diagnosis and screening. Pearson correlation tests and Receiver operating characteristic (ROC) curve were used to analyze the relationships between AVV hyperplasia, vasa vasorum (VV) hyperplasia and the intima-media thickness (IMT). SDT was developed for the treatment of arterial AVV hyperplasia and AS plaques.

RESULTS

The presence of local AVV in carotid unstable plaques correlated with the echogenic properties of the carotid plaque and the extent of plaque progression; Furthermore local AVV hyperplasia in patients with carotid atherosclerotic plaques was associated with acute coronary syndrome (ACS) events; Local AVV hyperplasia in patients with carotid atherosclerotic plaques was associated with coronary artery stenosis. Notably, SDT reduced local AVV hyperplasia and shrank the plaques in human femoral and carotid atherosclerotic lesions.

CONCLUSIONS

The presence of AVV in human carotid arteries reflects the severity of carotid and coronary artery AS. Further, SDT can reduce the hyperplasia of local AVV in human femoral and carotid plaques.

Hypoxia induced exosomal Circ-ZNF609 promotes pre-metastatic niche formation and cancer progression via miR-150-5p/VEGFA and HuR/ZO-1 axes in esophageal squamous cell carcinoma

Exosomes derived from cancer are regarded as significant mediators of cancer-host crosstalk. Hypoxia, on the other hand, is one of the essential characteristics of solid tumors. This research set out to discover how circulating exosomes from hypoxic esophageal squamous cell carcinoma (ESCC) contribute to the formation of metastatic niches and distant metastasis. First, we noticed that human umbilical vein endothelial cells (HUVECs) had their tight connections disrupted and the expression of proteins involved in angiogenesis boosted by ESCC hypoxic exosomes. Hypoxia significantly induced Circ-ZNF609 expression in exosomes from ESCC, which was then internalized by HUVECs, as determined by circular RNA screening. High Circ-ZNF609 expression in HUVECs facilitated angiogenesis and vascular permeability, thereby promoting pre-metastatic niche formation, and enhancing distant metastasis in vitro and in vivo. Exosomal Circ-ZNF609 activated vascular endothelial growth factor A (VEGFA) mechanistically by sponging miR-150-5p. Exosomal Circ-ZNF609 also interacted with HuR and inhibited HuR binding to ZO-1, Claudin-1, and Occludin mRNAs, thereby reducing their translation. Collectively, our findings identified an essential function for exosomal Circ-ZNF609 from ESCC cells, suggesting the potential therapeutic value of exosomes for ESCC patients.

VEGF signaling: Role in angiogenesis and beyond

Angiogenesis is a crucial process for tissue development, repair, and tumor survival. Vascular endothelial growth factor (VEGF) is a key driver secreted by cancer cells, promoting neovascularization. While VEGF's role in angiogenesis is well-documented, its influence on the other aspects in tumor microenvironemt is less discussed. This review elaborates on VEGF's impact on intercellular interactions within the tumor microenvironment, including how VEGF affects pericyte proliferation and migration and mediates interactions between tumor-associated macrophages and cancer cells, resulting in PDL-1-mediated immunosuppression and Nrf2-mediated epithelial-mesenchymal transition. The review discusses VEGF's involvement in intra-organelle crosstalk, tumor metabolism, stemness, and epithelial-mesenchymal transition. It also provides insights into current anti-VEGF therapies and their limitations in cancer treatment. Overall, this review aims to provide a thorough overview of the current state of knowledge concerning VEGF signaling and its impact, not only on angiogenesis but also on various other oncogenic processes.

NRP1 interacts with endoglin and VEGFR2 to modulate VEGF signaling and endothelial cell sprouting

Endothelial cells express neuropilin 1 (NRP1), endoglin (ENG) and vascular endothelial growth factor receptor 2 (VEGFR2), which regulate VEGF-A-mediated vascular development and angiogenesis. However, the link between complex formation among these receptors with VEGF-A-induced signaling and biology is yet unclear. Here, we quantify surface receptor interactions by IgG-mediated immobilization of one receptor, and fluorescence recovery after photobleaching (FRAP) measurements of the mobility of another coexpressed receptor. We observe stable ENG/NRP1, ENG/VEGFR2, and NRP1/VEGFR2 complexes, which are enhanced by VEGF-A. ENG augments NRP1/VEGFR2 interactions, suggesting formation of tripartite complexes bridged by ENG. Effects on signaling are measured in murine embryonic endothelial cells expressing (MEEC+/+) or lacking (MEEC-/-) ENG, along with NRP1 and/or ENG overexpression or knockdown. We find that optimal VEGF-A-mediated phosphorylation of VEGFR2 and Erk1/2 requires ENG and NRP1. ENG or NRP1 increase VEGF-A-induced sprouting, becoming optimal in cells expressing all three receptors, and both processes are inhibited by a MEK1/2 inhibitor. We propose a model where the maximal potency of VEGF-A involves a tripartite complex where ENG bridges VEGFR2 and NRP1, providing an attractive therapeutic target for modulation of VEGF-A signaling and biological responses.

Exploring the interactions of antihistamine with retinoic acid receptor beta (RARB) by molecular dynamics simulations and genome-wide meta-analysis

Kaposi sarcoma (KS) is one of the most common AIDS-related malignant neoplasms, which can leave lesions on the skin among HIV patients. These lesions can be treated with 9-cis-retinoic acid (9-cis-RA), an endogenous ligand of retinoic acid receptors that has been FDA-approved for treatment of KS. However, topical application of 9-cis-RA can induce several unpleasant side effects, like headache, hyperlipidemia, and nausea. Hence, alternative therapeutics with less side effects are desirable. There are case reports associating over-the-counter antihistamine usage with regression of KS. Antihistamines competitively bind to H1 receptor and block the action of histamine, best known for being released in response to allergens. Furthermore, there are already dozens of antihistamines that are FDA-approved with less side effects than 9-cis-RA. This led our team to conduct a series of in-silico assays to determine whether antihistamines can activate retinoic acid receptors. First, we utilized high-throughput virtual screening and molecular dynamics simulations to model high-affinity interactions between antihistamines and retinoic acid receptor beta (RARβ). We then performed systems genetics analysis to identify a genetic association between H1 receptor itself and molecular pathways involved in KS. Together, these findings advocate for exploration of antihistamines against KS, starting with our two promising hit compounds, bepotastine and hydroxyzine, for experimental validation study in the future.

HSPA5 Promotes the Proliferation, Metastasis and Regulates Ferroptosis of Bladder Cancer

Heat shock protein family A (HSP70) member 5 (HSPA5) is aberrantly expressed in various tumors and closely associated with the progression and prognosis of cancer. Nevertheless, its role in bladder cancer (BCa) remains elusive. The results of our study demonstrated that HSPA5 was upregulated in BCa and correlated with patient prognosis. Cell lines with low expression level of HSPA5 were constructed to explore the role of this protein in BCa. HSPA5 knockdown promoted apoptosis and retarded the proliferation, migration and invasion of BCa cells by regulating the VEGFA/VEGFR2 signaling pathway. In addition, overexpression of VEGFA alleviated the negative effect of HSPA5 downregulation. Moreover, we found that HSPA5 could inhibit the process of ferroptosis through the P53/SLC7A11/GPX4 pathway. Hence, HSPA5 can facilitate the progression of BCa and may be used as a novel biomarker and latent therapeutic target in the clinic.

Inhibition of MMPs supports amoeboid angiogenesis hampering VEGF-targeted therapies via MLC and ERK 1/2 signaling

BACKGROUND

In the past decades studies on anti-tumoral drugs inhibiting matrix metalloproteinase (MMPs) were disappointing. Recently, we demonstrated that mature endothelial cells (ECs) and endothelial colony forming cells (ECFCs) can switch between invasion modes to cope with challenging environments, performing the "amoeboid angiogenesis" in the absence of proteases activity.

METHODS

We first set out to investigate by ELISA if the inhibitors of the main protease family involved in angiogenesis were differently expressed during breast cancer progression. We used Marimastat, a broad-spectrum MMP inhibitor, as a means of inducing amoeboid characteristics and studied VEGF role in amoeboid angiogenesis. Thus, we performed invasion and capillary morphogenesis assay, morphological, cell signaling and in vivo mouse studies.

RESULTS

Our data showed that TIMP1, TIMP2, alpha2-antiplasmin, PAI-1 and cystatin increase in breast cancer serum of patients with primary cancer and lymph node positive compared to healthy women. In vitro results revealed that the most high-powered protease inhibitors able to induce amoeboid invasion of ECFCs were TIMP1, 2 and 3. Surprisingly, Marimastat promotes ECFC invasion and tubular formation in vitro and in vivo, inducing amoeboid characteristics. We observed that the combination of Marimastat plus VEGF doesn't boost neither cell invasion nor vessel formation capacity. Moreover, inhibition of VEGF activity with Bevacizumab in the presence of Marimastat confirmed that amoeboid angiogenesis is independent from the stimulus of the main vascular growth factor, VEGF.

CONCLUSIONS

We underline the importance to consider the amoeboid mechanism of endothelial and cancer cell invasion, probably responsible for the failure of synthetic metalloproteinase inhibitors as cancer therapy and tumor resistance to VEGF-targeted therapies, to set-up new drugs to be used in cancer therapy.

The endothelial-enriched lncRNA LINC00607 mediates angiogenic function

Long non-coding RNAs (lncRNAs) can act as regulatory RNAs which, by altering the expression of target genes, impact on the cellular phenotype and cardiovascular disease development. Endothelial lncRNAs and their vascular functions are largely undefined. Deep RNA-Seq and FANTOM5 CAGE analysis revealed the lncRNA LINC00607 to be highly enriched in human endothelial cells. LINC00607 was induced in response to hypoxia, arteriosclerosis regression in non-human primates, post-atherosclerotic cultured endothelial cells from patients and also in response to propranolol used to induce regression of human arteriovenous malformations. siRNA knockdown or CRISPR/Cas9 knockout of LINC00607 attenuated VEGF-A-induced angiogenic sprouting. LINC00607 knockout in endothelial cells also integrated less into newly formed vascular networks in an in vivo assay in SCID mice. Overexpression of LINC00607 in CRISPR knockout cells restored normal endothelial function. RNA- and ATAC-Seq after LINC00607 knockout revealed changes in the transcription of endothelial gene sets linked to the endothelial phenotype and in chromatin accessibility around ERG-binding sites. Mechanistically, LINC00607 interacted with the SWI/SNF chromatin remodeling protein BRG1. CRISPR/Cas9-mediated knockout of BRG1 in HUVEC followed by CUT&RUN revealed that BRG1 is required to secure a stable chromatin state, mainly on ERG-binding sites. In conclusion, LINC00607 is an endothelial-enriched lncRNA that maintains ERG target gene transcription by interacting with the chromatin remodeler BRG1 to ultimately mediate angiogenesis.

Towards a potential pan-cancer prognostic signature for gene expression based on probesets and ensemble machine learning

Cancer is one of the leading causes of death worldwide and can be caused by environmental aspects (for example, exposure to asbestos), by human behavior (such as smoking), or by genetic factors. To understand which genes might be involved in patients’ survival, researchers have invented prognostic genetic signatures: lists of genes that can be used in scientific analyses to predict if a patient will survive or not. In this study, we joined together five different prognostic signatures, each of them related to a specific cancer type, to generate a unique pan-cancer prognostic signature, that contains 207 unique probesets related to 187 unique gene symbols, with one particular probeset present in two cancer type-specific signatures (203072_at related to the MYO1E gene). We applied our proposed pan-cancer signature with the Random Forests machine learning method to 57 microarray gene expression datasets of 12 different cancer types, and analyzed the results. We also compared the performance of our pan-cancer signature with the performances of two alternative prognostic signatures, and with the performances of each cancer type-specific signature on their corresponding cancer type-specific datasets. Our results confirmed the effectiveness of our prognostic pan-cancer signature. Moreover, we performed a pathway enrichment analysis, which indicated an association between the signature genes and a protein-protein interaction analysis, that highlighted PIK3R2 and FN1 as key genes having a fundamental relevance in our signature, suggesting an important role in pan-cancer prognosis for both of them.

Ocular Drug Delivery: Advancements and Innovations

Ocular drug delivery has been significantly advanced for not only pharmaceutical compounds, such as steroids, nonsteroidal anti-inflammatory drugs, immune modulators, antibiotics, and so forth, but also for the rapidly progressed gene therapy products. For conventional non-gene therapy drugs, appropriate surgical approaches and releasing systems are the main deliberation to achieve adequate treatment outcomes, whereas the scope of “drug delivery” for gene therapy drugs further expands to transgene construct optimization, vector selection, and vector engineering. The eye is the particularly well-suited organ as the gene therapy target, owing to multiple advantages. In this review, we will delve into three main aspects of ocular drug delivery for both conventional drugs and adeno-associated virus (AAV)-based gene therapy products: (1) the development of AAV vector systems for ocular gene therapy, (2) the innovative carriers of medication, and (3) administration routes progression.

TMEM16A Plays an Insignificant Role in Myocardium Remodeling but May Promote Angiogenesis of Heart During Pressure-overload

Background: Cardiac hypertrophy (CH) occurs with an increase in myocardium mass as an adaptive compensation to increased stress. Prolonged CH causes decompensated heart failure (HF). Enhanced angiogenesis by vascular endothelial growth factor (VEGF) is observed in hypertrophied hearts; impaired angiogenesis by angiotensin II (AngII) is observed in failing hearts. Angiogenesis is executed by vascular endothelial cells (ECs). Abnormal Ca²⁺ homeostasis is a hallmark feature of hypertrophied and failing hearts. Ca²⁺-activated chloride channel transmembrane protein 16A (TMEM16A) is expressed in cardiomyocytes and ECs but its role in heart under stress remains unknown.

Methods: Pressure-overload-induced CH and HF mouse models were established. Echocardiography was performed to evaluate cardiac parameters. Quantitative real-time PCR, traditional and simple western assays were used to quantify molecular expression. Whole-cell patch-clamp experiments were used to detect TMEM16A current (I_TMEM16A) and action potential duration (APD) of cardiomyocytes. VEGF and AngII were used separately in ECs culture to simulate enhanced or impaired angiogenesis, respectively. TMEM16A low-expressed and over-expressed ECs were obtained by siRNA or lentivirus transfection. Wound healing, tube formation and ECs spheroids sprouting assays were performed to assess migration and angiogenesis.

Results: Neither TMEM16A molecular expression levels nor whole-cell I_TMEM16A density varied significantly during the development of CH and HF. I_TMEM16A comprises transient outward current, but doesn’t account for APD prolongation in hypertrophied or failing cardiomyocytes. In cultured ECs, TMEM16A knockdown inhibited migration and angiogenesis, TMEM16A overexpression showed opposite result. Promotion of migration and angiogenesis by VEGF was decreased in TMEM16A low-expressed ECs but was increased in TMEM16A over-expressed ECs. Inhibition of migration and angiogenesis by AngII was enhanced in TMEM16A low-expressed ECs but was attenuated in TMEM16A over-expressed ECs.

Conclusion: TMEM16A contributes insignificantly in myocardium remodeling during pressure-overload. TMEM16A is a positive regulator of migration and angiogenesis under normal condition or simulated stress. TMEM16A may become a new target for upregulation of angiogenesis in ischemic disorders like ischemic heart disease.

Ligustilide Inhibits Tumor Angiogenesis by Downregulating VEGFA Secretion from Cancer-Associated Fibroblasts in Prostate Cancer via TLR4

CAFs secrete VEGFA in the tumor microenvironment to induce angiogenesis and promote tumor growth. The downregulation of VEGFA secretion from CAFs helps block angiogenesis and exerts an anti-tumor effect. In vivo experiments showed that the angiogenesis of the tumor-bearing mice in the ligustilide group was significantly reduced. The results of MTT, tube formation, Transwell and scratch experiments showed that ligustilide did not affect the proliferation of HUVECs in a certain concentration range (<60 μM), but it inhibited the proliferation, tube formation and migration of HUVECs induced by CAFs. At this concentration, ligustilide did not inhibit CAF proliferation. The qPCR and WB results revealed that ligustilide downregulated the level of VEGFA in CAFs via the TLR4-ERK/JNK/p38 signaling pathway, and the effect was attenuated by blockers of the above molecules. Ligustilide also downregulated the autocrine VEGFA of HUVECs induced by CAFs, which inhibited angiogenesis more effectively. In addition, ligustilide inhibited glycolysis and HIF-1 expression in CAFs. Overall, ligustilide downregulated the VEGFA level in CAFs via the TLR4-ERK/JNK/p38 signaling pathway and inhibited the promotion of angiogenesis. This study provides a new strategy for the anti-tumor effect of natural active molecules, namely, blockade of angiogenesis, and provides a new candidate molecule for blocking angiogenesis in the tumor microenvironment.

[New findings on pathogenetic mechanisms in the development of age-related macular degeneration]

Age-related macular degeneration (AMD) is a complex multifactorial disease that occurs due to disfunction and degeneration of retinal pigment epithelium (RPE) and choriocapillaris, as well as death of photoreceptors. The exact pathogenetic mechanism remains uncertain. The aging process is the main and the clearest risk factor of AMD. In the development of this condition, a special role belongs to the secretory phenotype of aging spreading from one cell to another and mediated by the secretion and release of growth factors, cytokines, chemokines, proteases, and other molecules. Another major contributor is oxidative stress caused by violations in the recirculation of vitamin A in the vision cycle and accompanied by accumulation of lipofuscin, which mediates the formation of iron-based oxidants that are toxic for mitochondria. Furthermore, prolonged oxidative stress and constant light exposure induce the development of inflammation in the retina. Accumulation of metabolic products and cellular defects with age can induce an inflammatory reaction that amplifies the damage. The inflammatory processes including innate immune response, activation of microglia and parainflammation that occur locally in the vascular membrane, pigment epithelium and neuroretina are very significant contributors to the age-related changes, their progression, and the development of advanced stages of AMD. Various growth factors play a special role in the development of choroidal neovascularization (CNV). Vascular endothelial growth factor A (VEGF-A) has traditionally been considered the main factor of neoangiogenesis and, consequently, the main therapeutic target, but in recent years various studies have determined the role of other factors - VEGF-B, C, D, PGF, Gal-1, angiopoietins. This article describes the main underlying mechanisms in the development of choroidal neovascularization including retinal aging, impaired metabolic activity, mitochondrial dysfunction, inflammatory reactions and genetic variations, as well as the role of various growth factors.

A Novel Bispecific Antibody Targeting PD-L1 and VEGF With Combined Anti-Tumor Activities

Therapeutic monoclonal antibodies (mAbs) blocking immune checkpoints have been mainly used as monotherapy. Recently, combination therapy targeting multiple immune checkpoints has recently been explored to increase anti-cancer efficacy. Particularly, a single molecule targeting more than one checkpoints has been investigated. As dual blocking of PD-1/PD-L1 and VEGF/VEGFR has demonstrated synergism in anti-tumor activities, we developed a novel bispecific antibody, termed HB0025, which is formed via fusing the domain 2 of vascular endothelial growth factor receptor 1 (VEGFR1D2) and anti-PD-L1 mAb by using mAb-Trap technology. HB0025 almost completely retains the binding affinities and the biological activities in-vitro when compared with the parent anti-PD-L1 mAb or VEGFR1D2 fusion protein. Preclinical data demonstrated that HB0025 was more effective in inhibiting cancer growth than anti PD-L1 mAb or VEGFR1D2 fusion protein. Thus, our bispecific antibody may bring about greater clinical benefits and broader indications.

Improving antitumor immunity using antiangiogenic agents: Mechanistic insights, current progress, and clinical challenges

Cancer immunotherapy, especially immune checkpoint blockade (ICB), has revolutionized oncology. However, only a limited number of patients benefit from immunotherapy, and some cancers that initially respond to immunotherapy can ultimately relapse and progress. Thus, some studies have investigated combining immunotherapy with other therapies to overcome resistance to monotherapy. Recently, multiple preclinical and clinical studies have shown that tumor vasculature is a determinant of whether immunotherapy will elicit an antitumor response; thus, vascular targeting may be a promising strategy to improve cancer immunotherapy outcomes. A successful antitumor immune response requires an intact "Cancer-Immunity Cycle," including T cell priming and activation, immune cell recruitment, and recognition and killing of cancer cells. Angiogenic inducers, especially vascular endothelial growth factor (VEGF), can interfere with activation, infiltration, and function of T cells, thus breaking the "Cancer-Immunity Cycle." Together with immunostimulation-regulated tumor vessel remodeling, VEGF-mediated immunosuppression provides a solid therapeutic rationale for combining immunotherapy with antiangiogenic agents to treat solid tumors. Following the successes of recent landmark phase III clinical trials, therapies combining immune checkpoint inhibitors (ICIs) with antiangiogenic agents have become first-line treatments for multiple solid tumors, whereas the efficacy of such combinations in other solid tumors remains to be validated in ongoing studies. In this review, we discussed synergies between antiangiogenic agents and cancer immunotherapy based on results from preclinical and translational studies. Then, we discussed recent progress in randomized clinical trials. ICI-containing combinations were the focus of this review because of their recent successes, but combinations containing other immunotherapies were also discussed. Finally, we attempted to define critical challenges in combining ICIs with antiangiogenic agents to promote coordination and stimulate collaboration within the research community.

Hypoxia Triggers the Intravasation of Clustered Circulating Tumor Cells

Circulating tumor cells (CTCs) are shed from solid cancers in the form of single or clustered cells, and the latter display an extraordinary ability to initiate metastasis. Yet, the biological phenomena that trigger the shedding of CTC clusters from a primary cancerous lesion are poorly understood. Here, when dynamically labeling breast cancer cells along cancer progression, we observe that the majority of CTC clusters are undergoing hypoxia, while single CTCs are largely normoxic. Strikingly, we find that vascular endothelial growth factor (VEGF) targeting leads to primary tumor shrinkage, but it increases intra-tumor hypoxia, resulting in a higher CTC cluster shedding rate and metastasis formation. Conversely, pro-angiogenic treatment increases primary tumor size, yet it dramatically suppresses the formation of CTC clusters and metastasis. Thus, intra-tumor hypoxia leads to the formation of clustered CTCs with high metastatic ability, and a pro-angiogenic therapy suppresses metastasis formation through prevention of CTC cluster generation.

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Hypoxia leads to cell-cell junction upregulation and intravasation of CTC clusters

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Hypoxic CTC clusters are highly metastatic compared to normoxic CTCs

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Increase in intra-tumor hypoxia leads to accelerated metastasis

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Treatment with EpB2 reduces hypoxia and prevents CTC cluster formation

Microglia increase tight-junction permeability in coordination with Müller cells under hypoxic condition in an in vitro model of inner blood-retinal barrier

Microglia and Müller cells (MCs) are believed to be critically involved in hypoxia-induced blood-retinal barrier (BRB) disruption, which is a major pathogenic factor of various retinopathies. However, the underlying mechanism remains poorly defined. The inner BRB (iBRB) is primarily formed of microvascular endothelial cells (ECs) with tight junction (TJ), which are surrounded and supported by retinal glial cells. We developed a novel in vitro iBRB model sheet by sandwiching Transwell membrane with layered mouse brain microvascular ECs (bEnd.3) and mouse retinal MCs (QMMuC-1) on each side of the membrane. Using this model, we tested the hypothesis that under hypoxic condition, activated microglia produce inflammatory cytokines such as interleukin (IL)-1β, which may promote vascular endothelial growth factor (VEGF) production from MCs, leading to TJ disruption. The iBRB model cell sheets were exposed to 1% oxygen for 6 h with or without mouse brain microglia (BV2) or IL-1β. TJ structure and function were examined by zonula occludens (ZO)-1 immunostaining and fluorescein isothiocyanate permeability assay, respectively. Relative gene expression of IL-1β in BV2 under normoxic and hypoxic conditions was examined by real-time reverse transcription-polymerase chain reaction. VEGF protein concentration in QMMuC-1 supernatants was measured by enzyme-linked immunosorbent assay. The bEnd.3 cell sheet incubated with BV2 in hypoxic condition or with IL-1β in normoxic condition showed abnormal localization of ZO-1 and aberrated barrier function. Under normoxic condition, EC-MC iBRB model cell sheet showed lower permeability than bEnd.3 cell sheet. Under hypoxic conditions, the barrier function of EC-MC iBRB model cell sheet was more deteriorated compared to bEnd.3 cell sheet. Under hypoxic condition, incubation of EC-MC iBRB model cell sheet with BV2 cells or IL-1β significantly increased barrier permeability, and hypoxia-treated BV2 cells expressed significantly higher levels of IL-1β mRNA. Incubation of QMMuC-1 with IL-1β increased VEGF production. These results suggest that under hypoxic condition, microglia are activated to release proinflammatory cytokines such as IL-1β that promote VEGF production from MCs, leading to disruption of iBRB function. Modulating microglia and MCs function may be a novel approach to treat hypoxia-induced retinal BRB dysfunction.

Human plasminogen-derived N-acetyl-Arg-Leu-Tyr-Glu antagonizes VEGFR-2 to prevent blood-retinal barrier breakdown in diabetic mice

Targeting the vascular endothelial growth factor (VEGF)/its receptor-2 (VEGFR-2) system has become a mainstay of treatment for many human diseases, including retinal diseases. We examined the therapeutic effect of recently developed N-acetylated Arg-Leu-Tyr-Glu (Ac-RLYE), a human plasminogen kringle-5 domain-derived VEGFR-2 antagonists, on the pathogenesis of diabetic retinopathy. Ac-RLYE inhibited VEGF-A-mediated VEGFR-2 activation and endothelial nitric oxide synthase (eNOS)-derived NO production in the retinas of diabetic mice. In addition, Ac-RLYE prevented the disruption of adherens and tight junctions and vascular leakage by inhibiting S-nitrosylation of β-catenin and tyrosine nitration of p190RhoGAP in the retinal vasculature of diabetic mice. Peptide treatment preserved the pericyte coverage of retinal capillaries by upregulating angiopoietin-2. These results suggest that Ac-RLYE potentially prevents blood-retinal barrier breakdown and vascular leakage by antagonizing VEGFR-2; Ac-RLYE can be used as a potential therapeutic drug for the treatment of diabetic retinopathy.

End-to-End Deep Learning Model for Predicting Treatment Requirements in Neovascular AMD From Longitudinal Retinal OCT Imaging

Neovascular age-related macular degeneration (nAMD) is nowadays successfully treated with anti-VEGF substances, but inter-individual treatment requirements are vastly heterogeneous and currently poorly plannable resulting in suboptimal treatment frequency. Optical coherence tomography (OCT) with its 3D high-resolution imaging serves as a companion diagnostic to anti-VEGF therapy. This creates a need for building predictive models using automated image analysis of OCT scans acquired during the treatment initiation phase. We propose such a model based on deep learning (DL) architecture, comprised of a densely connected neural network (DenseNet) and a recurrent neural network (RNN), trainable end-to-end. The method starts by sampling several 2D-images from an OCT volume to obtain a lower-dimensional OCT representation. At the core of the predictive model, the DenseNet learns useful retinal spatial features while the RNN integrates information from different time points. The introduced model was evaluated on the prediction of anti-VEGF treatment requirements in nAMD patients treated under a pro-re-nata (PRN) regimen. The DL model was trained on 281 patients and evaluated on a hold-out test set of 69 patient. The predictive model achieved a concordance index of 0.7 in regressing the number of received treatments, while in a classification task it obtained an 0.85 (0.81) AUC in detecting the patients with low (high) treatment requirements. The proposed model outperformed previous machine learning strategies that relied on a set of spatio-temporal image features, showing that the proposed DL architecture successfully learned to extract the relevant spatio-temporal patterns directly from raw longitudinal OCT images.

circ_2858 Helps Blood-Brain Barrier Disruption by Increasing VEGFA via Sponging miR-93-5p during Escherichia coli Meningitis

Meningitic Escherichia coli invasion of the host brain can lead to increased blood-brain barrier (BBB) permeability. Circular RNAs (circRNAs) are non-coding RNAs, highly abundant in the brain, that are widely involved in the pathological processes of central nervous system (CNS) disorders; however, whether circRNAs participate in the regulation of BBB permeability during E. coli meningitis remains unknown. Here, we identified a novel circRNA, circ_2858, that was significantly upregulated in human brain microvascular endothelial cells (hBMECs) upon meningitic E. coli infection. We also found that circ_2858 regulated BBB permeability in hBMECs by competitively binding miR-93-5p, thereby inducing the upregulation of vascular endothelial growth factor A and finally resulting in downregulation as well as altered distribution of tight junction proteins such as ZO-1, Occludin, and Claudin-5. These findings provide novel insights into the influence of circ_2858 on BBB permeability during the pathogenic process of E. coli meningitis, suggesting potential nucleic acid targets for future prevention and therapy of CNS infection induced by meningitic E. coli.

Sphingosine-1-Phosphate Receptor 1 Activity Promotes Tumor Growth by Amplifying VEGF-VEGFR2 Angiogenic Signaling

The vascular endothelial growth factor-A (VEGF-A)-VEGFR2 pathway drives tumor vascularization by activating proangiogenic signaling in endothelial cells (ECs). Here, we show that EC-sphingosine-1-phosphate receptor 1 (S1PR1) amplifies VEGFR2-mediated angiogenic signaling to enhance tumor growth. We show that cancer cells induce S1PR1 activity in ECs, and thereby, conditional deletion of S1PR1 in ECs (EC-S1pr1^−/− mice) impairs tumor vascularization and growth. Mechanistically, we show that S1PR1 engages the heterotrimeric G-protein Gi, which amplifies VEGF-VEGFR2 signaling due to an increase in the activity of the tyrosine kinase c-Abl1. c-Abl1, by phosphorylating VEGFR2 at tyrosine-951, prolongs VEGFR2 retention on the plasmalemma to sustain Rac1 activity and EC migration. Thus, S1PR1 or VEGFR2 antagonists, alone or in combination, reverse the tumor growth in control mice to the level seen in EC-S1pr1^−/− mice. Our findings suggest that blocking S1PR1 activity in ECs has the potential to suppress tumor growth by preventing amplification of VEGF-VEGFR2 signaling.

Vijay Avin et al. demonstrate an essential role of endothelial cell (EC)-S1PR1 signaling in amplifying VEGFR2-mediated tumor growth. S1PR1 by Gi and c-Abl1 phosphorylates VEGFR2 at Y951, which retains VEGFR2 at EC plasmalemma, thus enabling EC migration, tumor angiogenesis, and growth.

Bioinformatical Analysis of miRNA-mRNA Interaction Network Underlying Macrophage Aging and Cholesterol-Responsive Difference between Young and Aged Macrophages

Purpose

Macrophage aging is involved with the occurrence and progression of age-related macular degeneration (AMD). The purpose of this study was to identify the specific microRNAs (miRNA), mRNAs, and their interactions underlying macrophage aging and response to cholesterol through bioinformatical analysis in order to get a better understanding of the mechanism of AMD.

Methods

The microarray data were obtained from Gene Expression Omnibus (accession GSE111304 and GSE111382). The age-related differentially expressed genes in macrophages were identified using R software. Further miRNA-mRNA interactions were analyzed through miRWalk, mirTarBase, starBase, and then produced by Cytoscape. The functional annotations including Gene Ontology and KEGG pathways of the miRNA target genes were performed by the DAVID and the STRING database. In addition, protein-protein interaction network was constructed to identify the key genes in response to exogenous cholesterol.

Results

When comparing aged and young macrophages, a total of 14 miRNAs and 101 mRNAs were detected as differentially expressed. Besides, 19 validated and 544 predicted miRNA-mRNA interactions were detected. Lipid metabolic process was found to be associated with macrophage aging through functional annotations of the miRNA targets. After being treated with oxidized and acetylated low-density lipoprotein, miR-714 and 16 mRNAs differentially expressed in response to both kinds of cholesterol between aged and young macrophages. Among them, 6 miRNA-mRNA predicted pairs were detected. The functional annotations were mainly related to lipid metabolism process and farnesyl diphosphate farnesyl transferase 1 (FDFT1) was identified to be the key gene in the difference of response to cholesterol between aged and young macrophages.

Conclusions

Lipid metabolic process was critical in both macrophage aging and response to cholesterol thus was regarded to be associated with the occurrence and progression of AMD. Moreover, miR-714-FDFT1 may modulate cholesterol homeostasis in aged macrophages and have the potential to be a novel therapeutic target for AMD.

Association between Single Nucleotide Polymorphisms in Cardiovascular Developmental Critical Genes and Hypertension: A Propensity Score Matching Analysis

Cardiovascular development critical genes are key determinants in cardiovascular diseases. We hypothesize that SNPs in these genes may play critical roles in the development of hypertension. Therefore, we enrolled 516 paired hypertension patients and controls in a total of 2,742 subjects in a cross-sectional population study by the propensity score matching (PSM) method. Twenty-one SNPs from 5 cardiovascular developmental related genes were detected by the improved multiplex ligase detection reaction (iMLDR) method. Conditioned logistic regression under three different genetic models, namely, additive model, dominant model, and recessive model, was performed. The odds ratio (ORs) and 95% confidence intervals (95% CIs) were used to estimate the associations of SNPs with hypertension. We found that the distribution of genotypes at rs833061, rs3025010, and rs699947 within the VEGFA gene and the distribution of alleles at rs3025010 in hypertension subjects were different from those in controls. Both rs833061 and rs3025010 were associated with hypertension in crude models, but only rs3025010 remains associated with hypertension after adjusting with confounding factors in the additive model and the dominant model. We also found that hypertension subjects with C/T and C/C genotypes at rs3025010 had lower SBP and DBP levels. In addition, rs3025010 could interact with rs6784267 within the CCM3 gene in the association. In conclusion, our findings suggest that rs3025010 may play a role in the pathogenesis of hypertension, which may be a potential target for individualized prevention and treatment of hypertension.

The Core-Clock Gene NR1D1 Impacts Cell Motility In Vitro and Invasiveness in A Zebrafish Xenograft Colon Cancer Model

Malfunctions of circadian clock trigger abnormal cellular processes and influence tumorigenesis. Using an in vitro and in vivo xenograft model, we show that circadian clock disruption via the downregulation of the core-clock genes BMAL1, PER2, and NR1D1 impacts the circadian phenotype of MYC, WEE1, and TP53, and affects proliferation, apoptosis, and cell migration. In particular, both our in vitro and in vivo results suggest an impairment of cell motility and a reduction in micrometastasis formation upon knockdown of NR1D1, accompanied by altered expression levels of SNAI1 and CD44. Interestingly we show that differential proliferation and reduced tumour growth in vivo may be due to the additional influence of the host-clock and/or to the 3D tumour architecture. Our results raise new questions concerning host–tumour interaction and show that core-clock genes are involved in key cancer properties, including the regulation of cell migration and invasion by NR1D1 in zebrafish xenografts.

Angiocrine endothelium: from physiology to cancer

The concept of cancer as a cell-autonomous disease has been challenged by the wealth of knowledge gathered in the past decades on the importance of tumor microenvironment (TM) in cancer progression and metastasis. The significance of endothelial cells (ECs) in this scenario was initially attributed to their role in vasculogenesis and angiogenesis that is critical for tumor initiation and growth. Nevertheless, the identification of endothelial-derived angiocrine factors illustrated an alternative non-angiogenic function of ECs contributing to both physiological and pathological tissue development. Gene expression profiling studies have demonstrated distinctive expression patterns in tumor-associated endothelial cells that imply a bilateral crosstalk between tumor and its endothelium. Recently, some of the molecular determinants of this reciprocal interaction have been identified which are considered as potential targets for developing novel anti-angiocrine therapeutic strategies.

Oral Delivery of a Tetrameric Tripeptide Inhibitor of VEGFR1 Suppresses Pathological Choroid Neovascularization

Age-related macular degeneration (AMD) is the primary cause of blindness in advanced countries. Repeated intravitreal delivery of anti-vascular endothelial growth factor (VEGF) agents has represented an important advancement for the therapy of wet AMD with significative results in terms of blindness prevention and partial vision restore. Nonetheless, some patients are not responsive or do not attain significant visual improvement, intravitreal injection may cause serious complications and important side effects have been reported for the prolonged block of VEGF-A. In order to evaluate new anti-angiogenic strategies, we focused our attention on VEGF receptor 1 (VEGFR1) developing a specific VEGFR-1 antagonist, a tetrameric tripeptide named inhibitor of VEGFR 1 (iVR1). We have evaluated its anti-angiogenic activity in the preclinical model of AMD, the laser-induced choroid neovascularization (CNV). iVR1 is able to potently inhibit CNV when delivered by intravitreal injection. Surprisingly, it is able to significantly reduce CNV also when delivered by gavage. Our data show that the specific block of VEGFR1 in vivo represents a valid alternative to the block of VEGF-A and that the inhibition of the pathological neovascularization at ocular level is also possible by systemic delivery of compounds not targeting VEGF-A.

Sonodynamic Therapy Suppresses Neovascularization in Atherosclerotic Plaques via Macrophage Apoptosis-Induced Endothelial Cell Apoptosis

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DVDMS-SDT reduces neovascularization in late-stage atherosclerotic lesions in both rabbit and mouse models.

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DVDMS-SDT enhances macrophage foam cell apoptosis, which in turn induces neovessel endothelial cell apoptosis and inhibits its proliferation, migration, and tubulogenesis, termed apoptosis-induced apoptosis.

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Mechanistically, DVDMS-SDT induces macrophage foam cell apoptosis via mitochondrial-caspase pathway, which activates caspase 3 to cleave SP-1, leading to the reduction of HIF-1α and VEGF-A.

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In the pilot translational study, DVDMS-SDT reduces plaque angiogenesis and inhibits vessel inflammation.

During atherosclerosis plaque progression, pathological intraplaque angiogenesis leads to plaque rupture accompanied by thrombosis, which is probably the most important cause of arteries complications such as cerebral and myocardial infarction. Even though few treatments are available to mitigate plaque rupture, further investigation is required to develop a robust optimized therapeutic method. In this study using rabbit and mouse atherosclerotic models, sinoporphyrin sodium (DVDMS)-mediated sonodynamic therapy reduced abnormal angiogenesis and plaque rupture. Briefly, DVDMS is injected to animals, and then the plaque was locally exposed to pulse ultrasound for a few minutes. Furthermore, a small size clinical trial was conducted on patients with atherosclerosis. Notably, a significant reduction of arterial inflammation and angiogenesis was recorded following a short period of DVDMS-mediated sonodynamic therapy treatment. This beneficial outcome was almost equivalent to the therapeutic outcome after 3-month intensive statin treatment.

Astrocytes Modify Migration of PBMCs Induced by β-Amyloid in a Blood-Brain Barrier in vitro Model

Background

The brain is protected by the blood-brain barrier (BBB), constituted by endothelial cells supported by pericytes and astrocytes. In Alzheimer’s disease a dysregulation of the BBB occurs since the early phases of the disease leading to an increased access of solutes and immune cells that can participate to the central inflammatory response. Here we investigated whether astrocytes may influence endothelial-leukocytes interaction in the presence of amyloid-β (Aβ).

Methods

We used an in vitro BBB model, where endothelial cells, cultured alone or with astrocytes were exposed for 5 h to Aβ, both under resting or inflammatory conditions (TNFα and IFNγ), to evaluate endothelial barrier properties, as well as transendothelial migration of peripheral blood mononuclear cells (PBMCs).

Results

In the co-culture model, barrier permeability to solutes was increased by all treatments, but migration was only observed in inflammatory conditions and was prevented by Aβ treatment. On the contrary, in endothelial monocultures, Aβ induced leukocytes migration under resting conditions and did not modify that induced by inflammatory cytokines. In endothelial astrocyte co-cultures, a low molecular weight (MW) isoform of the adhesion molecule ICAM-1, important to allow interaction with PBMCs, was increased after 5 h exposure to inflammatory cytokines, an effect that was prevented by Aβ. This modulation by Aβ was not observed in endothelial monocultures. In addition, endothelial expression of β-1,4-N-acetylglucosaminyltransferase III (Gnt-III), responsible for the formation of the low MW ICAM-1 isoform, was enhanced in inflammatory conditions, but negatively modulated by Aβ only in the co-culture model. miR-200b, increased in astrocytes following Aβ treatment and may represent one of the factors involved in the control of Gnt-III expression.

Conclusion

These data point out that, at least in the early phases of Aβ exposure, astrocytes play a role in the modulation of leukocytes migration through the endothelial layer.

Arg-Leu-Tyr-Glu Suppresses Retinal Endothelial Permeability and Choroidal Neovascularization by Inhibiting the VEGF Receptor 2 Signaling Pathway

Vascular endothelial growth factor (VEGF) plays a pivotal role in pathologic ocular neovascularization and vascular leakage via activation of VEGF receptor 2 (VEGFR2). This study was undertaken to evaluate the therapeutic mechanisms and effects of the tetrapeptide Arg-Leu-Tyr-Glu (RLYE), a VEGFR2 inhibitor, in the development of vascular permeability and choroidal neovascularization (CNV). In cultured human retinal microvascular endothelial cells (HRMECs), treatment with RLYE blocked VEGF-A-induced phosphorylation of VEGFR2, Akt, ERK, and endothelial nitric oxide synthase (eNOS), leading to suppression of VEGF-A-mediated hyper-production of NO. Treatment with RLYE also inhibited VEGF-A-stimulated angiogenic processes (migration, proliferation, and tube formation) and the hyperpermeability of HRMECs, in addition to attenuating VEGF-A-induced angiogenesis and vascular permeability in mice. The anti-vascular permeability activity of RLYE was correlated with enhanced stability and positioning of the junction proteins VE-cadherin, β-catenin, claudin-5, and ZO-1, critical components of the cortical actin ring structure and retinal endothelial barrier, at the boundary between HRMECs stimulated with VEGF-A. Furthermore, intravitreally injected RLYE bound to retinal microvascular endothelium and inhibited laser-induced CNV in mice. These findings suggest that RLYE has potential as a therapeutic drug for the treatment of CNV by preventing VEGFR2-mediated vascular leakage and angiogenesis.

Litchi (Litchi chinensis Sonn.) flower proanthocyanidin fraction exhibited protective efficacy to suppress nickel-induced expression for vascular endothelial growth factor in HepG2 cells

The protective efficacy of litchi (Litchi chinensis Sonn.) flower proanthocyanidin fraction (LFPF) composed of (-)-epicatechin and proanthocyanidin A2 against vascular endothelial growth factor (VEGF) generation induced by nickel (Ni) in hepatocellular carcinoma (Hep G2) cells was studied. VEGF is an angiogenic inducer, which promotes tumor angiogenesis, leading to rapid tumor growth and metastasis. VEGF could be substantially induced in the Ni-mediated Hep G2 cells. Through LFPF treatment, the Ni-induced VEGF generation could be suppressed significantly. The inhibition of HIF-1α expression by blocking phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways, and the suppression of Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT 3), and Raf-1 proto-oncogene, serine/threonine kinase (RAF1)/mitogen-activated protein kinase (MEK1/2)/extracellular-signal-regulated kinase (ERK1/2) pathways are important molecular mechanisms for the LFPF action. LFPF should probably reduce the risk of liver cancer in Ni-contaminated environments by inhibiting VEGF expression. PRACTICAL APPLICATIONS: LFPF mainly contained (-)-epicatechin and proanthocyanidin A2. Our results demonstrated that LFPF considerably suppressed the Ni-induced VEGF expression through inhibition of JAK2/STAT 3 and RAF1/MEK1/2/ERK1/2 pathways and prohibited HIF-1α expression through blocking PI3K/AKT/mTOR pathway. Litchi flowers might have the potential to diminish the liver cancer risk in a Ni-contaminated environment through suitable treatment.

Insulin-like growth factor binding proteins and angiogenesis: from cancer to cardiovascular disease

Angiogenesis is a tightly regulated activity that is vital during embryonic development and for normal physiological repair processes and reproduction in healthy adults. Pathological angiogenesis is a driving force behind a variety of diseases including cancer and retinopathies, and inhibition of angiogenesis is a therapeutic option that has been the subject of much research, with several inhibitory agents now available for medical therapy. Conversely, therapeutic angiogenesis has been mooted as having significant potential in the treatment of ischemic conditions such as angina pectoris and peripheral arterial disease, but so far there has been less translation from lab to bedside. The insulin-like growth factor binding proteins (IGFBP) are a family of seven proteins essential for the binding and transport of the insulin-like growth factors (IGF). It is being increasingly recognised that IGFBPs have a significant role beyond simply modulating IGF activity, with evidence of both IGF dependent and independent actions through a variety of mechanisms. Moreover, the action of the IGFBPs can be stimulatory or inhibitory depending on the cell type and environment. Specifically the IGFBPs have been heavily implicated in angiogenesis, both pathological and physiological, and they have significant promise as targeted cell therapy agents for both pathological angiogenesis inhibition and therapeutic angiogenesis following ischemic injury. In this short review we will explore the current understanding of the individual impact of each IGFBP on angiogenesis, and the pathways through which these effects occur.

Temporal Splicing Switches in Elements of the TNF-Pathway Identified by Computational Analysis of Transcriptome Data for Human Cell Lines

Alternative splicing plays an important role in numerous cellular processes and aberrant splice decisions are associated with cancer. Although some studies point to a regulation of alternative splicing and its effector mechanisms in a time-dependent manner, the extent and consequences of such a regulation remains poorly understood. In the present work, we investigated the time-dependent production of isoforms in two Hodgkin lymphoma cell lines of different progression stages (HD-MY-Z, stage IIIb and L-1236, stage IV) compared to a B lymphoblastoid cell line (LCL-HO) with a focus on tumour necrosis factor (TNF) pathway-related elements. For this, we used newly generated time-course RNA-sequencing data from the mentioned cell lines and applied a computational pipeline to identify genes with isoform-switching behaviour in time. We analysed the temporal profiles of the identified events and evaluated in detail the potential functional implications of alterations in isoform expression for the selected top-switching genes. Our data indicate that elements within the TNF pathway undergo a time-dependent variation in isoform production with a putative impact on cell migration, proliferation and apoptosis. These include the genes TRAF1, TNFRSF12A and NFKB2. Our results point to a role of temporal alternative splicing in isoform production, which may alter the outcome of the TNF pathway and impact on tumorigenesis.

A repertoire of biomedical applications of noble metal nanoparticles

The emerging properties of noble metal nanoparticles are attracting huge interest from the translational scientific community. In this feature article, we highlight recent advances in the adaptation of noble metal nanomaterials and their biomedical applications in therapeutics, diagnostics and sensing.

Engineering therapeutic bispecific antibodies using CrossMab technology

Bispecific antibodies have recently gained major interest as they allow novel mechanisms-of-action and/or therapeutic applications that cannot be achieved using conventional IgG-based antibodies. A major issue in engineering IgG-based bispecific antibodies has been to enable the correct association of heavy and light chains resulting in correct assembly of the desired bispecific antibody in sufficient yield. Various approaches have been described during recent years to tackle this challenge. We have developed the so-called CrossMab technology that enforces correct light chain association based on the domain crossover of immunoglobulin domains in the Fab region of the bispecific antibody. This versatile technology allows the generation of different bispecific antibody formats including asymmetric heterodimeric monovalent 1 + 1 bispecific antibodies and asymmetric heterodimeric bispecific antibodies with 2 + 1 valency in combination with approaches enabling Fc-hetermodimerization like knob-into-hole technology as well as the generation of tetravalent symmetric bispecific antibodies with 2 + 2 valency, also known as Tandem-Fab based IgG antibodies, using processes suitable for the large scale production of therapeutic bispecific antibodies. Notably, as of now, at least eight different bispecific antibodies using CrossMab technology entered clinical development, and additional CrossMabs are in late preclinical development. This review provides a summary of the status and progress with the engineering and generation of CrossMab technology based bispecific antibodies as well as their therapeutic application.

Leukotriene B4 promotes neovascularization and macrophage recruitment in murine wet-type AMD models

Age-related macular degeneration (AMD), a progressive chronic disease of the central retina, is associated with aging and is a leading cause of blindness worldwide. Here, we demonstrate that leukotriene B4 (LTB4) receptor 1 (BLT1) promotes laser-induced choroidal neovascularization (CNV) in a mouse model for wet-type AMD. CNV was significantly less in BLT1-deficient (BLT1-KO) mice compared with BLT1-WT controls. Expression of several proangiogenic and profibrotic factors was lower in BLT1-KO eyes than in BLT1-WT eyes. LTB4 production in the eyes was substantially increased in the early phase after laser injury. BLT1 was highly expressed in M2 macrophages in vitro and in vivo, and ocular BLT1+ M2 macrophages were increased in the aged eyes after laser injury. Furthermore, M2 macrophages were rapidly attracted by LTB4 and subsequently produced VEGF-A- through BLT1-mediated signaling. Consequently, intravitreal injection of M2 macrophages augmented CNV formation, which was attenuated by BLT1 deficiency. Thus, laser-induced injury to the retina triggered LTB4 production and attracted M2 macrophages via BLT1, leading to development of CNV. A selective BLT1 antagonist (CP105696) and 3 LTB4 inhibitors (zileuton, MK-886, and bestatin) reduced CNV in a dose-dependent manner. CP105696 also inhibited the accumulation of BLT1+ M2 macrophages in the laser-injured eyes of aged mice. Together, these results indicate that the LTB4-BLT1 axis is a potentially novel therapeutic target for CNV of wet-type AMD.

VEGF165b, a splice variant of VEGF-A, promotes lung tumor progression and escape from anti-angiogenic therapies through a β1 integrin/VEGFR autocrine loop

Vascular endothelial growth factor-A (VEGF-A) is highly subjected to alternative pre-mRNA splicing that generates several splice variants. The VEGF_xxx and VEGF_xxxb families encode splice variants of VEGF-A that differ only at the level of six amino acids in their C-terminal part. The expression level of VEGF_xxx splice variants and their function as pro-angiogenic factors during tumor neo-angiogenesis have been well-described. The role of VEGF_xxxb isoforms is less well known, but they have been shown to inhibit VEGF_xxx-mediated angiogenesis, while being partial or weak activators of VEGFR receptors in endothelial cells. On the opposite, their role on tumor cells expressing VEGFRs at their surface remains largely unknown. In this study, we find elevated levels of VEGF₁₆₅b, the main VEGF_xxxb isoform, in 36% of non-small cell lung carcinoma (NSCLC), mainly lung adenocarcinoma (46%), and show that a high VEGF₁₆₅b/VEGF₁₆₅ ratio correlates with the presence of lymph node metastases. At the molecular level, we demonstrate that VEGF₁₆₅b stimulates proliferation and invasiveness of two lung tumor cell lines through a VEGFR/β1 integrin loop. We further provide evidence that the isoform-specific knockdown of VEGF₁₆₅b reduces tumor growth, demonstrating a tumor-promoting autocrine role for VEGF₁₆₅b in lung cancer cells. Importantly, we show that bevacizumab, an anti-angiogenic compound used for the treatment of lung adenocarcinoma patients, increases the expression of VEGF₁₆₅b and activates the invasive VEGFR/β1 integrin loop. Overall, these data highlight an unexpected role of the VEGF₁₆₅b splice variant in the progression of lung tumors and their response to anti-angiogenic therapies.

ATAD2 silencing decreases VEGFA secretion through targeting has-miR-520a to inhibit angiogenesis in colorectal cancer

ATPase family AAA domain-containing protein 2 (ATAD2) is involved in various types of cancers, including colorectal cancer. This study aimed to determine the role of ATAD2 in angiogenesis in colorectal cancer. Here, we downregulated ATAD2 expression in HCT116 and SW480 cells, and collected the conditioned medium (CM) from control and ATAD2-silenced cells. The effect of CM on human umbilical vein endothelial cells (HUVEC) was evaluated by using CCK-8, wound healing, tube formation, Western blot, and dual-luciferase reporter assays. Our results showed that the proliferation, migration, and tube formation of HUVEC were reduced in presence of ATAD2-silenced CM, and the levels of phosphorylated vascular endothelial growth factor receptor 2 (P-VEGFR2), CD31, and CD34 were downregulated. Mechanism studies showed that ATAD2 silencing regulated the expression of vascular endothelial growth factor A (VEGFA) and miR-520a. Moreover, we found that miR-520a could bind to ATAD2, and its inhibitor partly reversed the alterations in HUVEC induced by CM from ATAD2-silenced cells. In addition, we demonstrated that miR-520a directly bound to 3'-UTR of VEGFA and inhibited its expression. Collectively, our results indicate that ATAD2 inhibition suppresses VEGFA secretion by increasing miR-520a levels. Our study suggests ATAD2 as a potential therapeutic target for angiogenesis in colorectal cancer.

Unveiling a VEGF-mimetic peptide sequence in the IQGAP1 protein

The ability to modulate angiogenesis by chemical tools has several important applications in different scientific fields. With the perspective of finding novel proangiogenic molecules, we searched peptide sequences with a chemical profile similar to that of the QK peptide, a well described VEGF mimetic peptide. We found that residues 1617-1627 of the IQGAP1 protein show molecular features similar to those of the QK peptide sequence. The IQGAP1-derived synthetic peptide was analyzed by NMR spectroscopy and its biological activity was characterized in endothelial cells. These studies showed that this IQGAP1-derived peptide has a biological activity similar to that of VEGF and could be considered as a novel tool for reparative angiogenesis.

Rap1B promotes VEGF-induced endothelial permeability and is required for dynamic regulation of the endothelial barrier

Vascular endothelial growth factor (VEGF), a key angiogenic and permeability factor, plays an important role in new blood vessel formation. However, abnormal VEGF-induced VEGFR2 signaling leads to hyperpermeability. We have shown previously that Rap1, best known for promoting cell adhesion and vessel stability, is a critical regulator of VEGFR2-mediated angiogenic and shear-stress EC responses. To determine the role of Rap1 role in endothelial barrier dynamics, we examined vascular permeability in EC-specific Rap1A- and Rap1B-knockout mice, cell-cell junction remodeling and EC monolayer resistivity in Rap1-deficient ECs under basal, inflammatory or elevated VEGF conditions. Deletion of either Rap1 isoform impaired de novo adherens junction (AJ) formation and recovery from LPS-induced barrier disruption in vivo However, only Rap1A deficiency increased permeability in ECs and lung vessels. Interestingly, Rap1B deficiency attenuated VEGF-induced permeability in vivo and AJ remodeling in vitro Therefore, only Rap1A is required for the maintenance of normal vascular integrity. Importantly, Rap1B is the primary isoform essential for normal VEGF-induced EC barrier dissolution. Deletion of either Rap1 isoform protected against hyper permeability in the STZ-induced diabetes model, suggesting clinical implications for targeting Rap1 in pathologies with VEGF-induced hyperpermeability.

Exploring the association of rs10490924 polymorphism with age-related macular degeneration: An in silico approach

The polymorphism rs10490924 (A69S) in the age-related maculopathy susceptibility 2 (ARMS2) gene is highly associated with age-related macular degeneration, which is the leading cause of blindness among the elderly population. ARMS2 gene encodes a putative small (11 kDa) protein, which the function and localization of the ARMS2 protein remain under debate. For a better understanding of functional impacts of A69S mutation, we performed a detailed analysis of an ARMS2 sequence with a broad set of bioinformatics tools. In silico analysis was followed to predict the tertiary structure, putative binding site regions, and binding site residues. Also, the effects of this mutation on protein stability, aggregation propensity, and homodimerization were analyzed. Next, a molecular dynamic simulation was carried out to understand the dynamic behavior of wild-type, A69S, and phosphorylated A69S structures. The results showed alterations in the putative post-translational modification sites on the ARMS2 protein, due to the mutation. Furthermore, the stability of protein and putative homodimer conformations were affected by the mutation. Molecular dynamic simulation results revealed that A69S mutation enhances the rigidity of the ARMS2 structure and residue serine at position 69 is buried and may not be phosphorylated; however, phosphorylated serine enhances the flexibility of the ARMS2 structure. In conclusion, our study provides new insights into the deleterious effects of A69S mutation on the ARMS2 structure.

Exploring the association of rs10490924 polymorphism with age-related macular degeneration: An in silico approach

The polymorphism rs10490924 (A69S) in the age-related maculopathy susceptibility 2 (ARMS2) gene is highly associated with age-related macular degeneration, which is the leading cause of blindness among the elderly population. The ARMS2 gene encodes a putative small (11kDa) protein, which the function and localization of the ARMS2 protein remain under debate. For a better understanding of functional impacts of the A69S mutation, we performed a detailed analysis of the ARMS2 sequence with a broad set of bioinformatics tools. In silico analysis was followed to predict the tertiary structure, putative binding site regions, and binding site residues. Also, the effects of this mutation on protein stability, aggregation propensity, and homodimerization were analyzed. Next, a molecular dynamic simulation was carried out to understand the dynamic behavior of wild-type, A69S, and phosphorylated A69S structures. The results showed alterations in the putative post-translational modification sites on the ARMS2 protein, due to the mutation. Furthermore, the stability of protein and putative homodimer conformations were affected by the mutation. Molecular dynamic simulation results revealed that the A69S mutation enhances the rigidity of the ARMS2 structure and residue serine at position 69 is buried and may not be phosphorylated; however, phosphorylated serine enhances the flexibility of the ARMS2 structure. In conclusion, our study provides new insights into the deleterious effects of the A69S mutation on the ARMS2 structure.

Effect of Anti-vascular Endothelial Growth Factor Antibody on the Survival of Cultured Retinal Ganglion Cells

Purpose

To investigate the effects of anti-vascular endothelial growth factor (VEGF) antibody on the survival of retinal ganglion cell (RGC)-5 cells differentiated with staurosporine under oxidative stress.

Methods

We used real-time polymerase chain reaction and Western blot to confirm the expression of VEGF, VEGF receptor (VEGFR)-1 and VEGFR-2 in RGC-5 cells differentiated with staurosporine for 6 hours. The differentiated RGC-5 cells were treated with 800 µM hydrogen peroxide (H₂O₂) for 24 hours to induce oxidative stress. Then, the survival rate of RGC-5 was confirmed by lactate dehydrogenase assay at each concentration (0, 0.01, 0.1, and 1 mg) using bevacizumab as the anti-VEGF antibody. The expression of VEGF, VEGFR-1, and VEGFR-2 was confirmed using real-time polymerase chain reaction.

Results

VEGF, VEGFR-1, and VEGFR-2 were all expressed in differentiated RGC-5 cells. When RGC-5 cells were simultaneously treated with bevacizumab and 800 µM H₂O₂, survival of RGC-5 decreased with bevacizumab concentration. VEGF expression in RGC-5 cells increased with increasing concentration of bevacizumab. Similar patterns were observed for VEGFR-1 and VEGFR-2, but the degree of increase was smaller than that for VEGF.

Conclusions

When bevacizumab was administered to differentiated RGC-5 cells, the cell damage caused by oxidative stress increased. Therefore, given these in vitro study results, caution should be exercised with bevacizumab treatment.