Expression Of Pro-angiogenic Genes Research Articles

Xenohormetic Phytochemicals Inhibit Neovascularization in Microphysiological Models of Vasculogenesis and Tumor Angiogenesis.

Xenohormesis proposes that phytochemicals produced to combat stressors in the host plant exert biochemical effects in animal cells lacking cognate receptors. Xenohormetic phytochemicals such as flavonoids and phytoalexins modulate a range of human cell signaling mechanisms but functional correlations with human pathophysiology are lacking. Here, potent inhibitory effects of grapefruit-derived Naringenin (Nar) and soybean-derived Glyceollins (Gly) in human microphysiological models of bulk tissue vasculogenesis and tumor angiogenesis are reported. Despite this interference of vascular morphogenesis, Nar and Gly are not cytotoxic to endothelial cells and do not prevent cell cycle entry. The anti-vasculogenic effects of Glyceollin are significantly more potent in sex-matched female (XX) models. Nar and Gly do not decrease viability or expression of proangiogenic genes in triple negative breast cancer (TNBC) cell spheroids, suggesting that inhibition of sprouting angiogenesis by Nar and Gly in a MPS model of the (TNBC) microenvironment are mediated via direct effects in endothelial cells. The study supports further research of Naringenin and Glyceollin as health-promoting agents with special attention to mechanisms of action in vascular endothelial cells and the role of biological sex, which can improve the understanding of dietary nutrition and the pharmacology of phytochemical preparations.

Abstract 5386: Increased sprouting angiogenesis in a microphysiological model of cisplatin-resistant recurrent lung cancers

Abstract Non-small cell lung cancer (NSCLC) constitutes 85% of total lung cancer cases and first-line therapies still often employ the platinum-based agents. Cisplatin therapy for NSCLC often leads to relapse of aggressive tumors with high metastatic potential after a period of dormancy. We hypothesize that cisplatin-resistant tumor cell phenotypes will increase features of aggressivity including sprouting angiogenesis in microphysiological models of NSCLC. First, we engineered various TME configurations using A549 cell spheroids and cancer associated fibroblasts (CAF) to establish a baseline of tumor cell proliferation, ECM deposition, and expression of proangiogenic and proinflammatory genes. Next, we generated cisplatin-resistant (Cis-R) A549 sub-lines to test the hypothesis that 3D tumor models engineered using these drug-resistant cells will capture hallmarks of highly aggressive recurrent tumors such as increased expression of progression-associated genes, increased induction of local stromal reactions and more profound angiogenesis. We treated parent A549 with 25 μM cisplatin for 96 hours followed by at least 14 days of recovery to generate Cis-R A549 cells. Interestingly, Cis-R spheroids exhibited significantly lower rates of proliferation (P<0.01) relative to parent A549 spheroids as measured by Ki67 index. Cis-R cells and spheroids exhibit increased genetic expression for genes involved in inflammation, EMT, proliferation and chemoresistance. Furthermore, Cis-R cells in 2D displayed a mesenchymal-like morphology and further exhibited dysmorphic spheroid morphology in 3D. We then developed a membrane free microphysiological system (MPS) comprised of two adjacent and contiguous tissue layers to investigate cancer mediated angiogenesis. We seeded one layer with lung fibroblasts and endothelial cells, which formed a vascularized network, while the other lane was cultured with no cells (control), parent A549 spheroids, or Cis-R A549 spheroids. Media void of VEGF was used throughout the duration of the experiment to isolate the effect of TME-derived factors. We measured increased angiogenetic sprouting induced by Cis-R tissues relative to parent using the following metrics: sprout density (Cis-R = 49.86 ± 10.93 µm/µm2, parent = 13.73 ± 4.12 µm/µm2, blank = 14.76 ± 4.22 µm/µm2), sprout length (Cis-R = 15006 ± 5507 µm, parent = 2466 ± 639.1 µm, blank = 4749 ± 1547 µm), and sprout area fraction (Cis-R = 0.10 ± 0.028, parent = 0.041 ± 0.010, blank = 0.032 ± 0.0095). Thus, the creation of drug resistant tumor cell sub lines enables the construction of more aggressive engineered tumor microenvironments. Future iterations of our MPS model will be used to investigate angiogenesis in the context of additional cancers, including breast and colon, while transitioning to the use of patient-derived organoids. Citation Format: Elisabet Olsen, G. Wills Kpeli, Omar M.K. Ahmad, Mark Mondrinos. Increased sprouting angiogenesis in a microphysiological model of cisplatin-resistant recurrent lung cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5386.

Cancer-associated Fibroblast-specific Expression of the Matricellular Protein CCN1 Coordinates Neovascularization and Stroma Deposition in Melanoma Metastasis.

In human patients, the expression of proangiogenic matricellular protein CCN1 in CAFs correlates positively with expression of stroma and angiogenic markers and progressive disease/resistance to checkpoint inhibitor therapy. In an animal model, loss of CCN1 from CAFs impaired metastasis of melanoma cells, neovascularization, and collagen deposition, emphasizing that CAFs coordinate cellular behavior in a tumor microenvironment and that CCN1 may be a novel target.

Abstract TMP5: Mutation of Pdgfrβ Enhances the Severity of Brain Arteriovenous Malformation on Endoglin Mutant Mice Through Exacerbation of Angiogenesis and Inflammation

Background and Purpose: Brain arteriovenous malformations (bAVMs) are tangles of abnormal vessels shunting blood directly from arteries to veins. Reduction of pericytes is correlated with bAVM hemorrhage. The PDGFB/PDGFRβ signaling plays important roles in regulating pericyte recruitment during angiogenesis. Hypothesis: Mutation of PDGFRβ causes cerebrovascular malformation and enhances bAVM severity in endoglin ( Eng ) deficient mice. Methods: Three mouse models were used: (1) Pdgfrβ F7 (F7) mice that have mutations disrupting most Pdgfrβ signaling, (2) Pdgfb icreER; Eng f/f mice that have Pdgfb promoter driving, tamoxifen (TM) inducible cre expression in endothelial cells (ECs) and a floxed Eng gene; and (3) PdgfbicreER; Eng f/f ;F7 +/- mice were used. Brain angiogenesis was induced by intra-parenchymal injection of AAV-VEGF. BAVMs were induced in PdgfbicreER; Eng f/f and PdgfbicreER; Eng f/f ;F7 +/- mice by inducting EC Eng deletion through TM treatment and brain angiogenesis through intra-brain injection of AAV-VEGF. BAVM phenotypes were analyzed 8-weeks after model induction by latex vascular cast to detect arteriovenous shunts, immunostaining to analyze vessel morphology, Prussian blue staining to quantify microhemorrhage and RNAseq to investigate gene expression profiles. Results: Dysplastic vessels with reduced pericyte coverage were detected in the brain and brain angiogenic region of F7 +/- and F7 +/+ mice. AVM like vessels were detected in the brain of 16% F7 +/- and 66% of F7 +/+ mice. F7 mutation increases bAVM penetrance in Eng deficient mice (71% vs 50%), dysplastic vessels and microhemorrhage. RNAseq data revealed that mutation of Pdgfrb increased the expression of pro-angiogenic and endothelial cell proliferation genes and genes promote cell migration and inflammation in the bAVMs of Eng mutant mice. Conclusion: Pdgfrβ mutation exacerbates the severity of bAVM in Eng mutant mice by enhancing angiogenesis and inflammation.

IL-21 promoting angiogenesis contributes to the development of psoriasis.

Elevated IL-21 expression which can effectively induce Th17 cell differentiation has been implicated in the pathogenesis of psoriasis, but its role in angiogenesis remains poorly understood. PASI and PSI score assessment was applied to evaluate the severity of psoriatic lesions. The expression of IL-21, IL-21 receptor (IL-21R), CD31, VEGFA, MMP-9, and ICAM-1 in skin was determined by immunohistochemistry or quantitative real-time polymerase chain reaction. The serum level of IL-21 was measured by enzyme-linked immunosorbent assay (ELISA). Then, their correlation was analyzed statistically. Human umbilical vein endothelial cells (HUVECs) cocultured with conditional medium from normal human epidermal keratinocytes (NHEKs) were treated with IL-21 and/or M5 cocktail (mixture of IL-1α, IL-17A, IL-22, TNF-α, and oncostatin M). The migration and tube formation of HUVECs were detected, and the levels of VEGFA, MMP-9, and ICAM-1 in NHEKs were measured by Western blotting or ELISA. Increased IL-21 and IL-21R expression was observed in psoriatic sera or skin specimens, with IL-21R mainly locating in keratinocytes and IL-21 in immune cells. Pearson analysis showed significantly positive correlation between IL-21/IL-21R and erythema scores/microvessel density in psoriatic lesions. Moreover, the expression of proangiogenic genes, VEGFA, ICAM-1, and MMP-9 was upregulated in skins of psoriasis. Additionally, in M5 microenvironment, migration and tube formation could be magnified in HUVECs using IL-21 pre-treated NHEK medium. Mechanically, the co-stimulation of IL-21 and M5 to NEHKs increased the expression of ICAM-1. IL-21 could regulate keratinocytes to secrete ICAM-1, thereby promoting angiogenesis in psoriasis.

Copper-containing titanium alloys promote the coupling of osteogenesis and angiogenesis by releasing copper ions

Previous investigations have reported on the ability of copper (Cu)-bearing biomaterials to accelerate vascular formation and bone regeneration. However, few studies have explored the effects of Cu-bearing materials on the interactions between angiogenesis and osteogenesis. Therefore, in this study, we prepared Cu-containing alloys using selective laser melting (SLM) technology and investigated the impact of preosteoblasts seeded on Ti6Al4V-4.5Cu alloy on angiogenesis. Our results indicated that Ti6Al4V-4.5Cu alloys increased the expression of proangiogenic genes and proteins in preosteoblasts, which further stimulated vascular formation in endothelial cells. Besides, we discovered that the biological effects of the Ti6Al4V-4.5Cu alloy were partly attributed to the release of Cu ions. In short, our research demonstrated the ability of Ti6Al4V-4.5Cu alloys to promote the coupling of angiogenesis and osteogenesis by releasing Cu ions.

Prostacyclin Released by Cancer-Associated Fibroblasts Promotes Immunosuppressive and Pro-Metastatic Macrophage Polarization in the Ovarian Cancer Microenvironment.

Metastasis of high-grade ovarian carcinoma (HGSC) is orchestrated by soluble mediators of the tumor microenvironment. Here, we have used transcriptomic profiling to identify lipid-mediated signaling pathways encompassing 41 ligand-synthesizing enzymes and 23 cognate receptors in tumor, immune and stroma cells from HGSC metastases and ascites. Due to its strong association with a poor clinical outcome, prostacyclin (PGI2) synthase (PTGIS) is of particular interest in this signaling network. PTGIS is highly expressed by cancer-associated fibroblasts (CAF), concomitant with elevated PGI2 synthesis, whereas tumor-associated macrophages (TAM) exhibit the highest expression of its surface receptor (PTGIR). PTGIR activation by PGI2 agonists triggered cAMP accumulation and induced a mixed-polarization macrophage phenotype with altered inflammatory gene expression, including CXCL10 and IL12A repression, as well as reduced phagocytic capability. Co-culture experiments provided further evidence for the interaction of CAF with macrophages via PGI2, as the effect of PGI2 agonists on phagocytosis was mitigated by cyclooxygenase inhibitors. Furthermore, conditioned medium from PGI2-agonist-treated TAM promoted tumor adhesion to mesothelial cells and migration in a PTGIR-dependent manner, and PTGIR activation induced the expression of metastasis-associated and pro-angiogenic genes. Taken together, our study identifies a PGI2/PTGIR-driven crosstalk between CAF, TAM and tumor cells, promoting immune suppression and a pro-metastatic environment.

The protein biosynthesis inhibitor vioprolide A evokes anti-angiogenic and pro-survival actions by targeting NOP14 and decreasing VEGF receptor 2- and TAZ-signaling.

Angiogenesis contributes to the progression of several diseases including cancer or age-related macular degeneration and is crucially driven by pathologically hyperactive endothelial cells (ECs). Targeting angiogenic processes in ECs thus represents a promising strategy to treat these conditions. Vioprolide A (vioA) is a myxobacterial cyclic depsipeptide that targets the nucleolar protein 14 (NOP14) and possesses strong anti-cancer and anti-inflammatory actions. Here, we present evidence that vioA promotes anti-angiogenic actions in vivo and in ECs in vitro. VioA reduced the choroidal neovascularization after laser-induced photocoagulation in mice in vivo, the sprouting of choroidal explant cultures ex vivo and key angiogenic features of ECs in vitro. Mechanistically, vioA decreased VEGFR2 protein levels and phosphorylation leading to impaired downstream pro-angiogenic signaling. Concurrently, vioA influenced TAZ signaling by diminishing its nuclear translocation and protein level, resulting in a reduced expression of pro-angiogenic target genes and dynamic cytoskeletal remodeling. Surprisingly, vioA induced pro-survival signaling in ECs by activating Akt and inhibiting p53-dependent apoptosis. Knockdown of the cellular target NOP14 further revealed a partial involvement in the anti-angiogenic and pro-survival actions of vioA. Taken together, our study introduces vioA as an interesting anti-angiogenic compound that warrants further investigations in preclinical studies.

High DNMT1 Expression in Stromal Fibroblasts Promotes Angiogenesis and Unfavorable Outcome in Locally Advanced Breast Cancer Patients

BackgroundActive breast cancer-associated fibroblasts (CAFs) play a leading role in breast carcinogenesis through promoting angiogenesis and resistance to therapy. Consequently, these active stromal cells have significant influence on patient outcome. Therefore, we explored here the role of the DNA methyltransferase 1 (DNMT1) protein in CAF-dependent promotion of angiogenesis as well as the prognostic power of DNMT1 level in both cancer cells and their adjacent CAFs in locally advanced breast cancer patients.MethodsWe applied immunohistochemistry to evaluate the level of DNMT1 in breast cancer tissues and their adjacent normal counterparts. Quantitative RT-PCR and immunoblotting were performed to investigate the role of DNMT1 in regulating the expression of pro-angiogenic genes in active CAFs and also their response to the DNMT1 inhibitors decitabine (DAC) as well as eugenol.ResultsWe have shown that DNMT1 controls the pro-angiogenic potential of CAFs both in vitro and in vivo through positive regulation of the expression/secretion of 2 important pro-angiogenic factors VEGF-A and IL-8 as well as their upstream effectors mTOR and HIF-1α. To confirm this, we have shown that these DNMT1-related pro-angiogenic effects were suppressed by 2 DNMT1 inhibitors decitabine and eugenol. Interestingly, in a cohort of 100 tumors from locally advanced breast cancer patients (LABC), we have shown that high expression of DNMT1 in tumor cells and their adjacent stromal fibroblasts is correlated with poor survival of these patients.ConclusionDNMT1 upregulation in breast stromal fibroblasts promotes angiogenesis via IL-8/VEGF-A upregulation, and correlates well with poor survival of LABC patients.

Human adipose mesenchymal stem cells modulate inflammation and angiogenesis through exosomes

Stem cell-derived exosomes are efficient and safe therapeutic tools for transferring endogenous biological cargo or functional biomolecules for regenerative medicine. The regulation of inflammation and angiogenesis plays a pivotal role in wound healing and tissue regeneration. The purpose of this study was to investigate the anti-inflammatory and pro-angiogenic roles of human adipose mesenchymal stem cell-derived exosomes, focusing on the underlying mechanisms. Exosomes inhibited LPS-induced inflammation by activating ROCK1 and PTEN expression. Moreover, microRNAs (miR-132 and miR-146a) released from exosomes upregulated the expression of pro-angiogenic genes and promoted proliferation activity and tube formation in human umbilical vein endothelial cells. Exosomal effects were verified using ROCK1/PTEN inhibitors for anti-inflammation and miR-132/miR-146a inhibitors for pro-angiogenesis. Our findings suggest that exosomes exert anti-inflammatory effects by targeting the ROCK1/PTEN pathway and exhibit pro-angiogenic effects via delivery of miR-132 and miR-146a. Taken together, these results suggest that exosomes may be promising therapeutic candidates for curing diseases involved in inflammation and angiogenesis.

Distinctive Roles of YAP and TAZ in Human Endothelial Progenitor Cells Growth and Functions.

The hippo signaling pathway plays an essential role in controlling organ size and balancing tissue homeostasis. Its two main effectors, yes-associated protein (YAP) and WW domain-containing transcription regulator 1, WWTR1 or TAZ, have also been shown to regulate endothelial cell functions and angiogenesis. In this study, the functions of YAP and TAZ in human endothelial progenitor cells (EPCs) were investigated by a loss-of-function study using CRISPR/Cas9-mediated gene knockdown (KD). Depletion of either YAP or TAZ reduced EPC survival and impaired many of their critical functions, including migration, invasion, vessel-formation, and expression of pro-angiogenic genes. Notably, TAZ-KD EPCs exhibited more severe phenotypes in comparison to YAP-KD EPCs. Moreover, the conditioned medium derived from TAZ-KD EPCs reduced the survivability of human lung cancer cells and increased their sensitivity to chemotherapeutic agents. The overexpression of either wild-type or constitutively active TAZ rescued the impaired phenotypes of TAZ-KD EPCs and restored the expression of pro-angiogenic genes in those EPCs. In summary, we demonstrate the crucial role of Hippo signaling components, YAP and TAZ, in controlling several aspects of EPC functions that can potentially be used as a drug target to enhance EPC functions in patients.

Dual l-Carnosine/Aloe vera Nanophytosomes with Synergistically Enhanced Protective Effects against Methylglyoxal-Induced Angiogenesis Impairment.

Microvascular complications are among the major outcomes of patients with type II diabetes mellitus, which are the consequences of impaired physiological functioning of small blood vessels and angiogenic responses in these patients. Overproduction and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl byproduct of glycolysis pathway, has been acclaimed as the main inducer of impaired angiogenic responses and microvascular dysfunction in diabetic patients with uncontrolled hyperglycemia. Hence, an effective approach to overcome diabetes-associated microvascular complications is to neutralize the deleterious activity of enhanced the concentration of MGO in the body. Owing to the glycation inhibitory activity of Aloe vera whole extract, and capability of l-carnosine, an endogenous dipeptide, in attenuating MGO's destructive activity, we examined whether application of a combination of l-carnosine and A. vera could be an effective way of synergistically weakening this reactive dicarbonyl's impaired angiogenic effects. Additionally, overcoming the poor cellular uptake and internalization of l-carnosine and A. vera, a nanophytosomal formulation of the physical mixture of two compounds was also established. Although l-carnosine and A. vera at whole studied combination ratios could synergistically enhance viability of human umbilical vein endothelial cells (HUVECs) treated with MGO, the 25:1 w/w ratio was the most effective one among the others (27 ± 0.5% compared to 12 ± 0.3 to 18 ± 0.4%; F (4, 15) = 183.9, P < 0.0001). Developing dual nanophytosomes of l-carnosine/A. vera (25:1) combination ratio, we demonstrated superiority of the nanophytosomal formulation in protecting HUVECs against MGO-induced toxicity following a 24-72 h incubation period (17.3, 15.8, and 12.4% respectively). Moreover, 500 μg/mL concentration of dual l-carnosine/A. vera nanophytosomes exhibited a superior free radical scavenging potency (63 ± 4 RFU vs 83 ± 5 RFU; F (5, 12) = 54.81, P < 0.0001) and nitric oxide synthesizing capacity (26.11 ± 0.19 vs 5.1 ± 0.33; F (5, 12) = 2537, P < 0.0001) compared to their physical combination counterpart. Similarly, 500 μg/mL dual l-carnosine/A. vera nanophytosome-treated HUVECs demonstrated a superior tube formation capacity (15 ± 3 vs 2 ± 0.3; F (5, 12) = 30.87, P < 0.001), wound scratch healing capability (4.92 ± 0.3 vs 3.07 ± 0.3 mm/h; F (5, 12) = 39.21, P < 0.0001), and transwell migration (586 ± 32 vs 394 ± 18; F (5, 12) = 231.8, P < 0.001) and invasion (172 ± 9 vs 115 ± 5; F (5, 12) = 581.1, P < 0.0001) activities compared to the physical combination treated ones. Further confirming the proangiogenic activity of the dual l-carnosine/A. vera nanophytosomes, a significant shift toward expression of proangiogenic genes including HIF-1α, VEGFA, bFGF, KDR, and Ang II was reported in treated HUVECs. Overall, dual l-carnosine/A. vera nanophytosomes could be a potential candidate for attenuating type II DM-associated microvascular complications with an impaired angiogenesis background.

RNA-binding protein SAMD4A inhibits breast tumor angiogenesis by modulating the balance of angiogenesis program.

Tumor‐induced angiogenesis is important for further progression of solid tumors. The initiation of tumor angiogenesis is dictated by a shift in the balance between proangiogenic and antiangiogenic gene expression programs. However, the potential mechanism controlling the expression of angiogenesis‐related genes in the tumor cells, especially the process mediated by RNA‐binding protein (RBP) remains unclear. SAMD4A is a conserved RBP across fly to mammals, and is believed to play an important role in controlling gene translation and stability. In this study, we identified the potential role of SAMD4A in modulating angiogenesis‐related gene expression and tumor progression in breast cancer. SAMD4A expression was repressed in breast cancer tissues and cells and low SAMD4A expression in human breast tumor samples was strongly associated with poor survival of patients. Overexpression of SAMD4A inhibited breast tumor angiogenesis and caner progression, whereas knockdown of SAMD4A demonstrated a reversed effect. Mechanistically, SAMD4A was found to specifically destabilize the proangiogenic gene transcripts, including C‐X‐C motif chemokine ligand 5 (CXCL5), endoglin (ENG), interleukin 1β (IL1β), and angiopoietin 1 (ANGPT1), by directly interacting with the stem‐loop structure in the 3′ untranslated region (3′UTR) of these mRNAs through its sterile alpha motif (SAM) domain, resulting in the imbalance of angiogenic genes expression. Collectively, our results suggest that SAMD4A is a novel breast tumor suppressor that inhibits tumor angiogenesis by specifically downregulating the expression of proangiogenic genes, which might be a potential antiangiogenic target for breast cancer therapy.

Roquin2 suppresses breast cancer progression by inhibiting tumor angiogenesis via selectively destabilizing proangiogenic factors mRNA.

Tumor angiogenesis is an essential step in tumor growth and metastasis. The initiation of tumor angiogenesis is dictated by a shift in the balance between proangiogenic and antiangiogenic gene expression programs. Roquin2 is a zinc-finger RNA-binding protein with important roles in mediating the expression of inflammatory genes, such as TNF, IL6 and PTGS2, which are also important angiogenic factors. In this study, we demonstrate that Roquin2 functions as a potent tumor angiogenesis regulator that inhibits breast tumor-induced angiogenesis by selectively destabilizing mRNA of proangiogenic gene transcripts, including endoglin (ENG), endothelin-1 (EDN1), vascular endothelial growth factor B (VEGFB) and platelet derived growth factor C (PDGFC). Roquin2 recognizes and binds the stem-loop structure in the 3'untranslated region (3'UTR) of these mRNAs via its ROQ domain to destabilize mRNA. Moreover, we found that Roquin2 expression was reduced in breast cancer cells and tissues, and associated with poor prognosis in breast cancer patients. Overexpression of Roquin2 inhibited breast tumor-induced angiogenesis in vitro and in vivo, whereas silencing Roquin2 enhanced tumor angiogenesis. In vivo induction of Roquin2 by adenovirus significantly suppressed breast tumor growth, metastasis and angiogenesis. Taken together, our results identify that Roquin2 is a novel breast cancer suppressor that inhibits tumor angiogenesis by selectively downregulating the expression of proangiogenic genes.

Engineered cell-degradable poly(2-alkyl-2-oxazoline) hydrogel for epicardial placement of mesenchymal stem cells for myocardial repair

Epicardial placement of mesenchymal stromal cells (MSCs) is a promising strategy for cardiac repair post-myocardial infarction, but requires the design of biomaterials to maximise the retention of donor cells on the heart surface and control their phenotype. To this end, we propose the use of a poly(2-alkyl-2-oxazoline) (POx) derivative, based on 2-ethyl-2-oxazoline and 2-butenyl-2-oxazoline. This POx polymer can be cured rapidly (less than 2 min) via photo-irradiation due to the use of di-cysteine cell degradable peptides. We report that the cell-degradable properties of the resulting POx hydrogels enables the regulation of cell protrusion in corresponding 3D matrices and that this, in turn, regulates the secretory phenotype of MSCs. In particular, the expression of pro-angiogenic genes was upregulated in partially cell-degradable POx hydrogels. Improved angiogenesis was confirmed in an in vitro microfluidic assay. Finally, we confirmed that, owing to the excellent tissue adhesive properties of thiol-ene crosslinked hydrogels, the epicardial placement of MSC-loaded POx hydrogels promoted the recovery of cardiac function and structure with reduced interstitial fibrosis and improved neovascular formation in a rat myocardial infarction model. This report demonstrates that engineered synthetic hydrogels displaying controlled mechanical, cell degradable and bioactive properties are particularly attractive candidates for the epicardial placement of stem cells to promote cardiac repair post myocardial infarction.

Pancreatic extracellular matrix and platelet-rich plasma constructing injectable hydrogel for pancreas tissue engineering.

The development of pancreatic extracellular matrices enriched with insulin-secreting β-cells is a promising tissue engineering approach to treat type 1 diabetes. However, its long-term therapeutic efficacy is restricted by the defensive mechanism of host immune response and the lack of developed vascularization as appropriate after transplantation. Platelet-rich plasma (PRP), as an autologous platelet concentrate, contains a large number of active factors that are essential for the cell viability, vascularization, and immune regulation. In this study, we have incorporated pancreatic extracellular matrix (PEM) with PRP to develop a three-dimensional (3D) injectable PEM-PRP hydrogel to coculture and transplant rat insulinoma cells (INS-1) and human umbilical vein endothelial cells (HUVECs). Results from this study demonstrated that PEM-PRP hydrogel mimicked the biochemical compositions of native extracellular matrices, and possessed the enhanced elastic modulus and resistance to enzymatic degradation that enabled biomaterials to maintain its volume and slowly degrade. Additionally, PEM-PRP hydrogel could release growth factors in a sustained manner. In vitro, PEM-PRP hydrogel significantly promoted the viability, insulin-secreting function, and insulin gene expression of gel encapsulated INS-1 cells. Moreover, HUVECs encapsulated in PEM-PRP hydrogel were found to constitute many lumen-like structures and exhibited high expression of proangiogenic genes. In vivo transplantation of PEM-PRP hydrogel encapsulated with INS-1 cells and HUVECs improved the viability of INS-1 cells, promoted vascularization, inhibited the host inflammatory response, and reversed hyperglycemia of diabetic rats. Our study suggests that the PEM-PRP hydrogel offers excellent biocompatibility and proangiogenic property, and may serve as an effective biomaterial platform to maintain the long-term survival and function of insulin-secreting β cells.

Biodegradable Films: Microporous Biodegradable Films Promote Therapeutic Angiogenesis (Adv. Healthcare Mater. 17/2020)

In article number 2000806 by Richard M. Day and co-workers, highly porous biodegradable films are prepared using thermally-induced phase separation. In vivo implantation of the films into ischemic tissue stimulates increased expression of pro-angiogenic growth factor genes. This provides a favourable local environment for neovascularization, increased tissue perfusion, and therapeutic angiogenesis in ischemic tissue. The findings pave the way to establishing new materials-based strategies to achieve therapeutic angiogenesis.

Docosahexaenoic acid (DHA) inhibits pro-angiogenic effects of breast cancer cells via down-regulating cellular and exosomal expression of angiogenic genes and microRNAs

AimsDocosahexaenoic acid (DHA) as an omega 3 free fatty acid has been reported to exert anti-angiogenesis effects. However, our current understanding regarding the precise mechanisms of such effects is still limited. Exosomes secreted by cancer cells may act as angiogenesis promoters. The aim of the study was to determine altered expression levels of HIF-1α, TGF-β, VEGFR, Snail1, Snail2 and SOX2 and their regulating microRNAs in MDA-MB-231 and BT-474 cell lines after treatment with DHA in both normoxic and hypoxic conditions. Main methodsHuman breast cancer cell lines including MDA-MB-231 and BT-474 were treated for 24 h with 100 uM DHA under normoxic and hypoxic conditions. Exosomes were isolated from untreated and treated cells and characterized by transmission electron microscopy (TEM) and western blotting. RNAs from cells and isolated exosomes were extracted and cDNAs were synthesized. Expression levels of miRNAs and their pro-angiogenic target genes were analyzed using quantitative real-time PCR (qRT-PCR). Key findingsWe showed significant decrease in the expression of pro-angiogenic genes including HIF1-α, TGF-β, SOX2, Snail1, Snail2 and VEGFR in cells and also their secreted exosomes after treatment with DHA in normoxic and hypoxic conditions. Also the expression levels of tumor suppressor miRs including miR-101, miR-199, miR-342 were increased and the expression levels of oncomiRs including mir-382 and miR-21 were decreased after treatment with DHA in cells and exosomes. SignificanceDHA can alter the expression of pro-angiogenic genes and microRNA contents in breast cancer cells and their derived-exosomes in favor of the inhibition of angiogenesis. Our data demonstrated new insight into DHA's anti-cancer action to target not only breast cancer cells but also their derived exosomes to suppress tumor angiogenesis.

Covid-19: Drug firms warn stockpiles have been eroded amid fears of no deal Brexit.

Angiopoietin 2 (ANGPT2) is a proangiogenic cytokine whose expression is often upregulated by endothelial cells in tumors. Expression of its receptor, TIE2, defines a highly proangiogenic subpopulation of myeloid cells in circulation and tumors called TIE2-expressing monocytes/macrophages (TEMs). Genetic depletion of TEMs markedly reduces tumor angiogenesis in various tumor models, emphasizing their essential role in driving tumor progression. Previously, we demonstrated that ANGPT2 augments the expression of various proangiogenic genes, the potent immunosuppressive cytokine, <i>IL-10</i>, and a chemokine for regulatory T cells (Tregs), <i>CCL17</i> by TEMs in vitro. We now show that TEMs also express higher levels of IL-10 than TIE2⁻ macrophages in tumors and that ANGPT2-stimulated release of IL-10 by TEMs suppresses T cell proliferation, increases the ratio of CD4⁺ T cells to CD8⁺ T cells, and promotes the expansion of CD4⁺CD25^highFOXP3⁺ Tregs. Furthermore, syngeneic murine tumors expressing high levels of ANGPT2 contained not only high numbers of TEMs but also increased numbers of Tregs, whereas genetic depletion of tumor TEMs resulted in a marked reduction in the frequency of Tregs in tumors. Taken together, our data suggest that ANGPT2-stimulated TEMs represent a novel, potent immunosuppressive force in tumors.

Crosstalk between dental pulp stem cells and endothelial cells augments angiogenic factor expression.

We aimed to investigate whether the mesenchymal stem cell-endothelial cell crosstalk enhances angiogenic factor expression via nuclear factor-kappa B (NF-κB)-dependent mechanisms. Human dermal microvascular endothelial cells (HDMECs) and stem cells from human exfoliated deciduous teeth (SHEDs) were cocultured for 96hr, in the presence of NF-κB decoy oligodeoxynucleotides (ODNs) or scramble (control). Vascular endothelial cell growth factor (VEGF) and phospho-NF-κB p65 were measured with enzyme-linked immunosorbent assay. Angiogenesis-related gene expression was analyzed with microarray analysis followed by real-time polymerase chain reaction. Tube formation assay was conducted in the presence of NF-κB decoy. The VEGF and phospho-NF-κB p65 levels were significantly higher in the coculture with NF-κB decoy scramble than in single culture and coculture with NF-κB decoy ODN. Microarray analysis of SHEDs and HDMECs with NF-κB decoy scramble showed higher expression of proangiogenic genes, Bcl-2, NF-κB1, VEGFA, CXCL8, and CXCR1, and lower expression of proapoptotic genes, Bax and Caspase 9, compared to cells with NF-κB decoy ODN. Real-time PCR results for Bcl-2 and CXCL8 showed a similar trend. Tube formation assay showed more tube development in the presence of NF-κB decoy scramble. The SHED-HDMEC crosstalk enhanced proangiogenic factor expression via NF-κB-dependent pathways.