Release Of Pro-angiogenic Factors Research Articles

Anesthetic management in malignant dural intracranial arteriovenous fistula. Literature review

Arteriovenous fistulas correspond to a rare type of cerebral vascular malformation, consisting of a direct connection between the meningeal arteries and the dural venous sinuses or leptomeningeal veins. They represent between 10-15% of cerebral vascular malformations. The main clinical picture of presentation is incidental, however, the symptoms can vary from mild symptoms such as tinnitus to cerebral hemorrhage. The formation of this systemic entity is attributable to different factors, among which are the release of proangiogenic factors, increased microthrombotic activity, increased expression of fibroblast growth factor and endothelial growth factor. The first-line diagnostic method is computed tomography, the gold standard is digital subtraction angiography.

In Vitro Coculture of Primary Human Cells to Analyze Angiogenesis, Osteogenesis, and the Inflammatory Response to Newly Developed Osteosynthesis Material for Pediatric Maxillofacial Traumatology: A Potential Pretesting Model before In Vivo Experiments

During the present study, an in vitro coculture bone tissue mimic based on primary osteoblasts and primary endothelial cells was used for a complex and broad evaluation of a newly developed material for applications in pediatric maxillofacial traumatology. The biomaterial was composed of PDLLA (poly(D,L-lactide)) in various combinations with calcium carbonate (CC), magnesium (Mg), and chitosan (CH). Besides classical biocompatibility analyses, the present study evaluated material-dependent effects on fundamental processes that are essential for successful material integration and regeneration. Therefore, inflammation-associated factors such as E-selectin and interleukins were analyzed in the in vitro model system on gene expression and protein level depending on the different materials. Furthermore, in order to test the capability of vascularization of the material, the effect of the different materials on the formation of microvessel-like structures as well as the expression and release of proangiogenic factors was investigated in vitro in the bone coculture model. In addition, the mineralization capacity as well as the relative gene expression of osteogenic differentiation factors was analyzed in response to the different materials. As a result, the authors could assess the material combination PDLLA: CC CH as the most functionally tested material with regard to biocompatibility, inflammatory response, and microvessel-like structure formation as well as osteogenic differentiation in the in vitro coculture system. In conclusion, by using tissue-engineered human bone tissue equivalents as proposed here in an in vitro coculture model, biomaterial-mediated effects can be readily investigated. Moreover, it is proposed that these complex in vitro evaluations could contribute to the understanding and improvement of the development of novel materials for pediatric traumatological care for prospective clinical applications.

Multipotent Mesenchymal Stem Cell-Based Therapies for Spinal Cord Injury: Current Progress and Future Prospects.

Spinal cord injury (SCI) represents a significant medical challenge, often resulting in permanent disability and severely impacting the quality of life for affected individuals. Traditional treatment options remain limited, underscoring the need for novel therapeutic approaches. In recent years, multipotent mesenchymal stem cells (MSCs) have emerged as a promising candidate for SCI treatment due to their multifaceted regenerative capabilities. This comprehensive review synthesizes the current understanding of the molecular mechanisms underlying MSC-mediated tissue repair in SCI. Key mechanisms discussed include neuroprotection through the secretion of growth factors and cytokines, promotion of neuronal regeneration via MSC differentiation into neural cell types, angiogenesis through the release of pro-angiogenic factors, immunomodulation by modulating immune cell activity, axonal regeneration driven by neurotrophic factors, and glial scar reduction via modulation of extracellular matrix components. Additionally, the review examines the various clinical applications of MSCs in SCI treatment, such as direct cell transplantation into the injured spinal cord, tissue engineering using biomaterial scaffolds that support MSC survival and integration, and innovative cell-based therapies like MSC-derived exosomes, which possess regenerative and neuroprotective properties. As the field progresses, it is crucial to address the challenges associated with MSC-based therapies, including determining optimal sources, intervention timing, and delivery methods, as well as developing standardized protocols for MSC isolation, expansion, and characterization. Overcoming these challenges will facilitate the translation of preclinical findings into clinical practice, providing new hope and improved treatment options for individuals living with the devastating consequences of SCI.

External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy

Abstract Objective Diabetic retinopathy (DR), a microvascular complication of diabetes, is a leading cause of preventable blindness. Spectral domain optical coherence tomography (SD-OCT) provides cross-sectional and topographical imaging of the retina. SD-OCT resolves outer retinal layers into three hyperreflective bands—external limiting membrane (ELM), ellipsoid zone (EZ), and retinal pigment epithelium (RPE). In this article, we have studied the role of these outer retinal layers in structural and molecular changes taking place in DR. Materials and Methods Articles with clinical features, pathogenesis, diagnosis, and treatment of DR were thoroughly studied. Articles were searched on PubMed, MEDLINE, and Cochrane Library from 2000 to 2020. Studies focusing on the role of ELM, EZ, and RPE in pathogenesis of DR based on SD-OCT were included. Results The long-standing hyperglycemia leads to protein glycosylation resulting in formation of advanced glycation end products (AGEs). AGEs have an impact through their effect on retinal microvasculature, vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1, nitrosative and oxidative stress, and vitamin D and calcium metabolism. All these factors have been linked with disruption of outer retinal layers. AGEs lead to vascular endothelial dysfunction and release of proangiogenic factors by increasing the expression of VEGF in retinal pericytes and RPE cells. This leads to leakage and fluid accumulation resulting in diabetic macular edema (DME). In DME, there is sequential disruption of ELM and EZ and decrease in visual acuity (VA). The RPE alterations have been reported to be associated with the severity of DR and decrease in VA. Anti-VEGF therapy, most common treatment of DME, leads to restoration of barrier effect of ELM, it was found to be restored first followed by EZ restoration. Newer anti-AGEs agents and their receptor blockers are being developed which have a positive effect on maintaining the health of RPE. Conclusion A complex molecular association exists between the structural changes in ELM, EZ, and RPE in DR. SD-OCT is an indispensable tool to study these changes as integrity of these outer layers of retina is essential for maintaining visual function of retina in DR.

ПАТОФИЗИОЛОГИЧЕСКИЕ АСПЕКТЫ ВОСПАЛИТЕЛЬНОГО И НЕВОСПАЛИТЕЛЬНОГО НЕОАНГИОГЕНЕЗА

Angiogenesis is a genetically determined mechanism for the formation of new vessels from progenitor cells; it is also a complex process of new vessels formation, that is regulated by an imbalance in the pro- and anti-angiogenic factors ratio. Angiogenesis is divided on physiological and pathological, which directly refers to angiogenesis in conditions of tumor pathology, and in conditions of inflammatory diseases. So the fundamental differences in the mechanisms base in the direct synthesis of vascular growth factors in tumor cells, or the release of pro-angiogenic factors by immune and stromal cells. Under conditions of inflammation, cytokines can directly induce vascular synthesis by recruiting angioblasts, or, indirectly, by inducing leukocytes and endothelial cells for the synthesis of pro-angiogenic mediators.

Acetyl-L-Carnitine downregulates invasion (CXCR4/CXCL12, MMP-9) and angiogenesis (VEGF, CXCL8) pathways in prostate cancer cells: rationale for prevention and interception strategies

BackgroundProstate cancer (PCa) is a leading cause of cancer-related death in males worldwide. Exacerbated inflammation and angiogenesis have been largely demonstrated to contribute to PCa progression. Diverse naturally occurring compounds and dietary supplements are endowed with anti-oxidant, anti-inflammatory and anti-angiogenic activities, representing valid compounds to target the aberrant cytokine/chemokine production governing PCa progression and angiogenesis, in a chemopreventive setting. Using mass spectrometry analysis on serum samples of prostate cancer patients, we have previously found higher levels of carnitines in non-cancer individuals, suggesting a protective role. Here we investigated the ability of Acetyl-L-carnitine (ALCAR) to interfere with key functional properties of prostate cancer progression and angiogenesis in vitro and in vivo and identified target molecules modulated by ALCAR.MethodsThe chemopreventive/angiopreventive activities ALCAR were investigated in vitro on four different prostate cancer (PCa) cell lines (PC-3, DU-145, LNCaP, 22Rv1) and a benign prostatic hyperplasia (BPH) cell line. The effects of ALCAR on the induction of apoptosis and cell cycle arrest were investigated by flow cytometry (FC). Functional analysis of cell adhesion, migration and invasion (Boyden chambers) were performed. ALCAR modulation of surface antigen receptor (chemokines) and intracellular cytokine production was assessed by FC. The release of pro-angiogenic factors was detected by a multiplex immunoassay. The effects of ALCAR on PCa cell growth in vivo was investigated using tumour xenografts.ResultsWe found that ALCAR reduces cell proliferation, induces apoptosis, hinders the production of pro inflammatory cytokines (TNF-α and IFN-γ) and of chemokines CCL2, CXCL12 and receptor CXCR4 involved in the chemotactic axis and impairs the adhesion, migration and invasion capabilities of PCa and BPH cells in vitro. ALCAR exerts angiopreventive activities on PCa by reducing production/release of pro angiogenic factors (VEGF, CXCL8, CCL2, angiogenin) and metalloprotease MMP-9. Exposure of endothelial cells to conditioned media from PCa cells, pre-treated with ALCAR, inhibited the expression of CXCR4, CXCR1, CXCR2 and CCR2 compared to those from untreated cells. Oral administration (drinking water) of ALCAR to mice xenografted with two different PCa cell lines, resulted in reduced tumour cell growth in vivo.ConclusionsOur results highlight the capability of ALCAR to down-modulate growth, adhesion, migration and invasion of prostate cancer cells, by reducing the production of several crucial chemokines, cytokines and MMP9. ALCAR is a widely diffused dietary supplements and our findings provide a rational for studying ALCAR as a possible molecule for chemoprevention approaches in subjects at high risk to develop prostate cancer. We propose ALCAR as a new possible “repurposed agent’ for cancer prevention and interception, similar to aspirin, metformin or beta-blockers.

S100B Protein Stimulates Proliferation and Angiogenic Mediators Release through RAGE/pAkt/mTOR Pathway in Human Colon Adenocarcinoma Caco-2 Cells

Chronic inflammation and angiogenesis are associated with colonic carcinogenesis. Enteric glia-derived S100B protein has been proposed as an “ideal bridge”, linking colonic inflammation and cancer, given its dual ability to up-regulate nuclear factor-kappaB (NF-κB) transcription via receptor for advanced glycation end products (RAGE) signaling and to sequestrate wild type pro-apoptotic wild type (wt)p53. However, its pro-angiogenic effects on cancer cells are still uninvestigated. To this aim, we evaluated the effect of exogenous S100B (0.05–5 µM) protein alone or in the presence of S100B blocking monoclonal antibody (mAb) (1:105–1:104 v/v diluted) on (1) cultured Caco-2 cells proliferation, migration and invasiveness in vitro, respectively by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT)-formazan, wound healing and matrigel invasion assays and (2) its effect on the release of pro-angiogenic factors, such as vascular endothelial growth factor (VEGF) by ELISA and immunofluorescence analyses. The effect of S100B alone or in the presence of S100BmAb was then investigated on RAGE/pAkt/mammalian target of rapamycin (mTOR) signaling pathway by immunoblot analysis. Our results showed that S100B markedly increases proliferation and invasiveness of Caco-2 cells, through the release of pro-angiogenic VEGF and NO paralleled to a significant decrease of wtp53 expression mediated by RAGE-p38 mitogen-activated protein kinase (MAPK)/pAkt-mTOR and hypoxia-inducible factor 1-alpha (HIF1α) pathways. Such effects were counteracted by S100BmAb, indicating that S100B targeting is a potential approach to inhibit colon carcinoma proliferation and angiogenesis.

Therapeutic potential of exosomes in rotator cuff tendon healing.

Rotator cuff tears are common musculoskeletal injuries that can cause significant pain and disability. While the clinical results of rotator cuff repair can be good, failure of tendon healing remains a significant problem. Molecular mechanisms underlying structural failure following surgical repair remain unclear. Histologically, enhanced inflammation, disorganization of the collagen fibers, calcification, apoptosis and tissue necrosis affect the normal healing process. Mesenchymal stem cells (MSCs) have the ability to provide improved healing following rotator cuff repair via the release of mediators from secreted 30-100nm extracellular vesicles called exosomes. They carry regulatory proteins, mRNA and miRNA and have the ability to increase collagen synthesis and angiogenesis through increased expression of mRNA and release of proangiogenic factors and regulatory proteins that play a major role in proper tissue remodeling and preventing extracellular matrix degradation. Various studies have shown the effect of exosomes on improving outcome of cutaneous wound healing, scar tissue formation, degenerative bone disease and Duchenne Muscular Dystrophy. In this article, we critically reviewed the potential role of exosomes in tendon regeneration and propose the novel use of exosomes alone or seeded onto biomaterial matrices to stimulate secretion of favorable cellular factors in accelerating the healing response following rotator cuff repair.

Microvascular density, macrophages, and mast cells in human clear cell renal carcinoma with and without bevacizumab treatment

BackgroundClear cell renal cell carcinoma (ccRCC) represents a highly vascularized aggressive kidney cancer. Due to ccRCC chemotherapy resistance, antiangiogenesis is one of the most innovative targeted therapies for this tumor. The tumor microenvironment exerts important roles in tumor growth, angiogenesis, and metastatic escape. Materials and methodsIn this study, we investigated the composition of tumor cell microenvironment including mast cells, macrophages, and microvascular density in ccRCC tumor tissues collected from patients who underwent nephrectomy treated or not with bevacizumab as neoadjuvant therapy before surgery. ResultsThe results of this study indicate that bevacizumab-treated ccRCC samples present reduced microvascular density as well as a lower number of CD68-positive macrophages and tryptase-positive mast cells in comparison with the untreated patients. ConclusionsIt follows that the antiangiogenic activity of bevacizumab may be due to a direct effect on angiogenic cytokines released by tumor cells and an indirect effect on the release of pro-angiogenic factors by inflammatory stromal cells.

Control of angiogenesis and host response by modulating the cell adhesion properties of an Elastin-Like Recombinamer-based hydrogel.

The control of the invivo vascularization of engineered tissue substitutes is essential in order to obtain either a rapid induction or a complete inhibition of the process (e.g. in muscles and hyaline-cartilage, respectively). Among the several polymers available, Elastin-Like Recombinamers (ELR)-based hydrogel stands out as a promising material for tissue engineering thanks to its viscoelastic properties, non-toxicity, and non-immunogenicity. In this study, we hypothesized that varying the cell adhesion properties of ELR-hydrogels could modulate the high angiogenic potential of adipose tissue-derived stromal vascular fraction (SVF) cells, predominantly composed of endothelial/mural and mesenchymal cells. Human SVF cells, embedded in RGD-REDV-bioactivated or unmodified ELR-hydrogels, were implanted in rat subcutaneous pockets either immediately or upon 5-day-culture in perfusion-bioreactors. Perfusion-based culture enhanced the endothelial cell cord-like-organization and the release of pro-angiogenic factors in functionalized constructs. While invivo vascularization and host cell infiltration within the bioactivated gels were highly enhanced, the two processes were strongly inhibited in non-functionalized SVF-based hydrogels up to 28 days. ELR-based hydrogels showed a great potential to determine the successful integration of engineered substitutes thanks to their capacity to finely control the angiogenic/inflammation process at the recipient site, even in presence of SVF cells.

The role of placenta-derived mesenchymal stem cells in healing of induced full-thickness skin wound in a mouse model.

We examined the effect of placenta-derived MSCs (PDMSCs) injection intraregionally and intraperitoneally on healing of induced full thickness mice skin wounds; moreover, the mechanisms by which MSCs exert their effects were also studied. Sixty female mice were divided into three groups after induction of full thickness skin wound; untreated group, wounded mice were injected with MSCs derived from human placenta intraperitoneally or intraregionally. Skin biopsies were obtained 7 and 12 days after wound incision for histological examinations, detection of vascular endothelial growth factor (VEGF) by ELISA, and estimation of expression of mouse ICAM-1, Integrin β1, Integrin β3 genes and human albumin and GAPDH genes by reverse transcription polymerase chain reaction. Human placenta derived-MSCs treated groups showed accelerated wound healing than non-treated group. VEGF, Integrin β1, and Integrin β3 levels were significantly increased in the intraregionally and intraperitoneally treated mice as compared to non-treated group at day 7 after wound induction. ICAM-1 showed significant decrease in its expression in treated groups compared with non-treated group. Interestingly, the intraperitoneal MSCs injections showed better results than intraregional one. PDMSCs accelerate full thickness skin wound healing and the intraperitoneal MSCs injections are more effective than intraregional one. MSCs promote wound healing through release of proangiogenic factors as VEGF, increase healing promoting factors as integrin β1 and β3, and decrease proinflammatory cytokines as ICAM-1.

Palmitoylethanolamide Regulates Production of Pro-Angiogenic Mediators in a Model of β Amyloid-Induced Astrogliosis In Vitro.

Aβ-induced astrogliosis can worsen the eziopathogenesis of Alzheimer disease (AD) by the release of proinflammatory and pro-oxidant mediators. Activated glial cells may release also pro-angiogenic molecules. The role of angiogenesis in AD is still controversial: although angiogenesis brings oxygen and nutrients to injured tissue, it may also exacerbate reactive gliosis. Moreover, by altering blood-brain barrier permeability pro-angiogenic mediators promote passage of inflammatory/immune-competent cells into the brain, thereby exacerbating gliosis. The release of proangiogenic factors during astrogliosis may thus be a key-step in controlling AD progression. The endogenous fatty acid amide, palmitoylethanolamide (PEA), is a pleiotropic mediator exerting anti-inflammatory, antinociceptive and antiangiogenic effects in several in vitro and in vivo models of chronic-degenerative disease. In this study, we investigated the effects of PEA in AD angiogenesis and neuroinflammation by using conditioned medium from untreated and Aβ-treated C6 rat astroglioma cells and HUVEC human endothelial cells. PEA (10-8-10-6 M) concentration-dependently reduced expression of pro-inflammatory and pro-angiogenic markers in Aβ (1 μg/mL)-stimulated C6 cells. Moreover, culture medium from PEA-treated C6 cells reduced HUVEC cell proliferation as compared to cells treated with conditioned medium from Aβ-treated C6 cells. Immunocytochemical analysis revealed that PEA treatment inhibited nuclear levels of mitogen-activated protein kinase 1 (the main pro-angiogenic pathway) and cytoplasmic vascular endothelial growth factor in HUVEC cells receiving C6 conditioned medium. Finally, the peroxisome proliferator-activated receptor alpha inhibitor GW6471, added to Aβ-treated C6 cells blocked all PEA effects in this model, suggesting that PEA acts through a proliferator-activated receptor alpha-dependent mechanism on astroglial cells. Collectively, these data support the potential therapeutic utility of PEA in AD.

Improved Angiogenesis in Response to Localized Delivery of Macrophage-Recruiting Molecules.

Successful engineering of complex organs requires improved methods to promote rapid and stable vascularization of artificial tissue scaffolds. Toward this goal, tissue engineering strategies utilize the release of pro-angiogenic growth factors, alone or in combination, from biomaterials to induce angiogenesis. In this study we have used intravital microscopy to define key, dynamic cellular changes induced by the release of pro-angiogenic factors from polyethylene glycol diacrylate hydrogels transplanted in vivo. Our data show robust macrophage recruitment when the potent and synergistic angiogenic factors, PDGFBB and FGF2 were used as compared with VEGF alone and intravital imaging suggested roles for macrophages in endothelial tip cell migration and anastomosis, as well as pericyte-like behavior. Further data from in vivo experiments show that delivery of CSF1 with VEGF can dramatically improve the poor angiogenic response seen with VEGF alone. These studies show that incorporating macrophage-recruiting factors into the design of pro-angiogenic biomaterial scaffolds is a key strategy likely to be necessary for stable vascularization and survival of implanted artificial tissues.

Role of synovial fibroblasts in rheumatoid arthritis.

Rheumatoid arthritis (RA) is the most common autoimmune articular disorder. It is characterized by chronic inflammation and progressive joint destruction. As research traditionally focused on immune cells and cytokines, the role of stromal cells was addressed only to a limited extent. However, cell-cell interactions within the rheumatoid synovium alter the phenotype of synovial fibroblasts (SFs), which are nowadays considered as active and aggressive drivers in the destructive process of RA. SFs actively attach to and invade articular cartilage, thereby expressing increased amounts of adhesion molecules and proinflammatory and matrix-degrading mediators. Furthermore, RASFs stimulate synovial vascularization through the release of proangiogenic factors. As a result, angiogenesis supports the influx of immune cells into affected joints, thereby perpetuating inflammatory processes, and facilitates access of RASFs to the bloodstream, thus boosting dissemination of RA. Despite intensive research, early pathophysiological processes still remain largely unknown. In this respect, a prearthritic phase of RA is discussed. Early and intensive therapy is considered to be very effective and beneficial for long-term outcome. However, although innovative therapy and improved treatment strategies are applied to achieve clinical remission, failure of or only partial response to therapy remains common. Given that none of the currently approved therapies target RASFs, intensive research into new strategies is warranted. In this review, novel findings leading to the altered fibroblast phenotype in RA are discussed in terms of progressive inflammation and destruction. Potential novel therapeutic concepts are also addressed.

Accumulation of dephosphorylated 4EBP after mTOR inhibition with rapamycin is sufficient to disrupt paracrine transformation by the KSHV vGPCR oncogene

Dysregulation of the PI3K/Akt/mTOR pathway is one of the most frequent events in human cancer. However, the clinical benefits of PI3K/Akt/mTOR inhibitors have not yet achieved their predicted potential in many of the most prevalent human cancers. Of interest, treatment of Kaposi's sarcoma (KS) patients with rapamycin provided the first evidence of the antineoplastic activity of mTOR inhibitors in humans, becoming the standard of care for KS arising in renal transplant patients. Thus, the study of KS may provide a unique opportunity to dissect the contribution of specific mTOR downstream targets to cancer development. The KS-associated herpesvirus (KSHV) is the etiological agent for KS, and the KSHV-encoded oncogene viral-G protein-coupled receptor (vGPCR) promotes the potent activation of the PI3K-Akt-mTOR pathway by both direct and paracrine mechanisms. We focused on a direct target of mTOR, EIF4EBP1/2/3 (4EBP), which inhibits the translation of eukaryotic initiation factor 4E (eiF4E)-bound mRNAs. 4EBP phosphorylation by mTOR relieves its inhibitory activity, hence resulting in increased eiF4E-dependent mRNA translation. We developed a paracrine transformation model, recapitulating the cellular composition of KS lesions, in which vGPCR-expressing cells promote the rapid proliferation of endothelial cells, thus expressing KSHV-latent genes by the release of growth factors. Using this model, we show here that the accumulation of dephosphorylated 4EBP in response to rapamycin or by the expression of an mTOR-insensitive mutant of 4EBP1 is sufficient to disrupt the eiF4E function downstream of mTOR to a similar extent than the mTOR catalytic inhibitor Torin2 and to halt KS development. We also provide evidence that eiF4E contributes to paracrine neoplastic, signaling through the release of pro-angiogenic factors that are acting on endothelial cells, expressing KSHV-latent genes. These findings may provide a preclinical platform and the rationale for the development of novel mTOR, inhibiting agents that may selectively disrupt the mTOR-4EBP interaction for the treatment of KS and other tumor lesions, exhibiting hyperactive mTOR pathway function.

Medicinal FungusAntrodia cinnamomeaInhibits Growth and Cancer Stem Cell Characteristics of Hepatocellular Carcinoma

Background. Antrodia cinnamomea is an edible fungus commonly used in Asia as a well-known medicinal herb capable of treating drug intoxication and liver cancer. Methods. This study evaluated the anticancer activity of its biotechnological product, mycelial fermentation broth (AC-MFB) on hepatocellular carcinoma (HCC) by tetrazolium-based colorimetric assay in vitro and syngeneic Balb/c 1MEA.7R.1 tumor implantation model in vivo. Given that cancer stem cell characteristics, such as angiogenesis, invasiveness, and migration, are known to cause recurrence, we further evaluated the effect of AC-MFB on cellular viability inhibition of HCC cells, angiogenic activity and migration of endothelial cells, and the release of proangiogenic factors from HCC cells. Results. We found that AC-MFB markedly inhibited the growth of HCC without hepatic enzyme abnormality. This anti-HCC activity was validated by growth-inhibitory effects on both cultured murine 1MEA.7R.1 and human HA22T/VGH HCC cells. For cancer stem cell characteristics, AC-MFB inhibited the cellular viability, migration, and tube formation activity of EA. hy926 and SVEC4-10 endothelial cells. Production of extracellular vascular endothelial growth factor and intracellular hypoxia-inducible factor-1 alpha from HCC cells was suppressed by AC-MFB. Conclusion. Antrodia cinnamomea could inhibit the growth and cancer stem cell characteristics of HCC cells.

Functional consequences of prolactin signalling in endothelial cells: a potential link with angiogenesis in pathophysiology?

Prolactin is best known as the polypeptide anterior pituitary hormone, which regulates the development of the mammary gland. However, it became clear over the last decade that prolactin contributes to a broad range of pathologies, including breast cancer. Prolactin is also involved in angiogenesis via the release of pro-angiogenic factors by leukocytes and epithelial cells. However, whether prolactin also influences endothelial cells, and whether there are functional consequences of prolactin-induced signalling in the perspective of angiogenesis, remains so far elusive. In the present study, we show that prolactin induces phosphorylation of ERK1/2 and STAT5 and induces tube formation of endothelial cells on Matrigel. These effects are blocked by a specific prolactin receptor antagonist, del1-9-G129R-hPRL. Moreover, in an in vivo model of the chorioallantoic membrane of the chicken embryo, prolactin enhances vessel density and the tortuosity of the vasculature and pillar formation, which are hallmarks of intussusceptive angiogenesis. Interestingly, while prolactin has only little effect on endothelial cell proliferation, it markedly stimulates endothelial cell migration. Again, migration was reverted by del1-9-G129R-hPRL, indicating a direct effect of prolactin on its receptor. Immunohistochemistry and spectral imaging revealed that the prolactin receptor is present in the microvasculature of human breast carcinoma tissue. Altogether, these results suggest that prolactin may directly stimulate angiogenesis, which could be one of the mechanisms by which prolactin contributes to breast cancer progression, thereby providing a potential tool for intervention.

Cross-talk between subchondral bone and articular cartilage in osteoarthritis

The interest in the relationship between articular cartilage and the structural and functional properties of peri-articular bone relates to the intimate contact that exists between these tissues in diarthrodial joints. Much of the interest and continuing controversy regarding the relationship between these tissues dates back to the original suggestion by Radin and Rose that alterations in the mechanical properties of subchondral bone could adversely affect the functional state of chondrocytes and the integrity of the overlying cartilage. They hypothesized that the deterioration in articular cartilage associated with the osteoarthritic process was secondary to an initial increase in subchondral bone stiffness induced by repetitive mechanical loading. Numerous approaches have been used to establish that the changes in periarticular bone occur very early in the development of OA. Although chondrocytes also have the capacity to modulate their functional state in response to loading, the capacity of these cells to repair and modify their surrounding extracellular matrix is relatively limited in comparison to the adjacent subchondral bone. This differential adaptive capacity likely underlies the more rapid appearance of detectable skeletal changes in OA in comparison to the articular cartilage. Given the intimate mechanical and biological interaction between the articular cartilage and subchondral bone it is likely that alterations in the composition and/or structural organization of either tissue will modulate the properties and function of the other joint component. An additional factor that affects the interaction between these tissues is the gradual expansion of the zone of calcified cartilage and advancement of the tidemark that occurs with aging and progression of OA and contributes to overall thinning of the articular cartilage. The precise mechanisms involved in this process have not been definitively established and could include the release of pro-angiogenic factors from chondrocytes in the deep zones of the articular cartilage that have undergone hypertrophy and/or the influences of microcracks that have initiated focal remodeling in the calcified cartilage in an attempt to repair the microdamage. In addition, this process markedly increases the mechanical stresses in the deep zones of the cartilage matrix, which likely contributes to the acceleration in OA cartilage deterioration. In summary, there is the need for further studies to define the pathophysiological mechanisms involved in the interaction between subchondral bone and articular cartilage and for applying this information to the development of therapeutic interventions to improve the outcomes in patients with OA.

Paracrine Effects Influenced by Cell Culture Medium and Consequences on Microvessel-Like Structures in Cocultures of Mesenchymal Stem Cells and Outgrowth Endothelial Cells

Mesenchymal stem cells (MSC) from bone marrow and outgrowth endothelial cells (OEC) from peripheral blood are considered as attractive cell types for applications in regenerative medicine aiming to build up complex vascularized tissue-engineered constructs. MSC provide several advantages such as the potential to differentiate to osteoblasts and to support the neovascularization process by release of proangiogenic factors. On the other hand, the neovascularization process can be actively supported by OEC forming perfused vascular structures after co-implantation with other cell types. In this study the formation of angiogenic structures in vitro was investigated in cocultures of MSC and OEC, cultured either in the medium for osteogenic differentiation of MSC (ODM) or in the medium for OEC cultivation endothelial cell growth medium-2 (EGM2 Bullet Kit). After 2 weeks, cocultures in EGM2 formed more microvessel-like structures compared to cocultures in ODM as demonstrated by immunofluorescence staining for the endothelial marker CD31. Increased expression of CD31 and CD146 in quantitative real-time polymerase chain reaction as well as a higher percentage of CD31- and CD146-positive cells in flow cytometry indicated a beneficial influence of EGM2 on endothelial cell growth and function. In addition, the improved formation of vascular structures in EGM2 correlates with higher levels of the proangiogenic factor vascular endothelial growth factor and platelet-derived growth factor in the supernatant of cocultures as well as in monocultures of MSC when cultivated in EGM-2. Nevertheless, ODM was more suitable for the differentiation of MSC to osteoblastic lineages in the cocultures, whereas EGM2 favored factors involved in vessel stabilization by pericytes. In conclusion, this study highlights the importance of medium components for cell interaction triggering the formation of angiogenic structures.

Abstract 3375: The epithelial to endotheliod transition (EET): A cellular modulation that promotes the head and neck squamous cell carcinoma tumorigenic phenotype

Abstract The presence of the EMT (epithelial-mesenchymal transition) and EndMT (endothelial-mesenchymal transition) demonstrates the extent of phenotypic plasticity in cancers. Previous findings in head and neck squamous cell carcinoma (HNSCC) cells, i.e., VEGF's autocrine-paracrine function and their responsiveness to endostatin, imply that HNSCC cells share some functional characteristics with endothelial cells and suggest the potential for an “epithelial-to-endotheliod transition (EET)”. Such a transition would facilitate HNSCC tumorigenesis by augmenting release of proangiogenic factors and facilitating tumor cell migration and invasion. Consequently, these studies elucidated whether or not an EET occurs in HNSCC cells and tumors, and evaluated cellular parameters to uniquely characterize this epithelial-endotheliod transition. Our results demonstrate that cultured HNSCC cells express a variety of endothelial-specific markers, and assumption of the endotheliod phenotype has functional consequences including uptake of acetylated low density lipoprotein and enhanced invasion and migration. Selective HNSCC cells were also highly responsive to transforming growth factor-β1 and express its auxiliary receptor, endoglin. Furthermore, the EET is not restricted to cultured HNSCC cells per se as tumor cells in resected human HNSCC tumors and proliferating epithelia at the margins of ulcers demonstrate a similar phenotype. These data suggest that, similar to EMT, the EET enhances epithelial cell migration. Also, the regulation of this transition-transient (wound healing) versus sustained (invasive cancers)-impacts clinical outcome. Finally, recognition of the EET as a distinct entity provides impetus for future clinical trials to concurrently assess the antitumorigenic as well as the angiostatic properties of therapeutic agents formally regarded as exclusively angiostatic in scope. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3375. doi:10.1158/1538-7445.AM2011-3375