Endothelial Cell Marker CD31 Research Articles

Decreased Uterine Vascularization and Uterine Arteriolar Expansive Remodeling by Matrix Metalloproteinases in Hypertensive Pregnancy

Normal pregnancy is associated with extensive remodeling of spiral arteries in order to maintain nutrients and blood supply to the growing fetus. Inadequate placentation and invasion of the uterine wall could lead to uteroplacental ischemia and hypertensive pregnancy (HTN‐Preg); however, the extent of uterine vascularization and the mechanisms involved are unclear. We hypothesized that HTN‐Preg is associated with changes in uterine vascularization and arterial remodeling by matrix metalloproteinases (MMPs). Blood pressure (BP) and fetal parameters were assessed on day‐19 in normal pregnant rats (Preg) and pregnant rats with reduced uterine perfusion pressure (RUPP), and the uteri were isolated for measurement of tissue vascularity and MMPs expression/activity. BP was greater and pups number and weight, and uterus weight were reduced in RUPP vs. Preg rats (BP 128.2±1.7 vs. 91.60±2.8mmHg; pups number 8.8±1.1 vs. 13.00±0.7; pup weight 1.48±0.059 vs. 2.02±0.02g; uterus weight 3.82±0.37 vs. 4.92±0.27g). Histological analysis of uterine tissue sections showed reduced total number and whole area of uterine arterioles in RUPP vs. Preg rats (number 5.75±0.95 vs. 11.50±0.87; area 0.05±0.01 vs. 0.12±0.02mm2). Immunohistochemistry with the endothelial cell marker CD31 showed localization in the uterine arterial intima and confirmed reduction in the number and size of uterine arterioles in RUPP vs. Preg rats. Further analysis of the uterine arterial wall showed reduction in the area of all three layers of the uterine arterial wall in RUPP vs. Preg rats (intima 0.015±0.003 vs. 0.031±0.005; media 0.012±0.002 vs. 0.038±0.005; adventitia 0.021±0.003 vs. 0.048±0.007mm2). Western blots and gelatin zymography showed a decrease in expression and activity of MMP‐2 and ‐9 in uterus and uterine arteries of RUPP vs. Preg rats. Immunohistochemistry showed decreased total amount of MMP‐2 and ‐9 in the uterus, and reduction in MMP distribution in the intima and media of uterine arteries of RUPP vs. Preg rats. Thus, in HTN‐Preg rats there is reduction in the number and size of uterine arteries and decreased expression and activity of MMP‐2 and ‐9. These results suggest that reduced uterine vascularization and uterine arteriolar expansive remodeling by MMPs could be a factor in the uteroplacental ischemia associated with HTN‐Preg and preeclampsia.Support or Funding InformationThis work was supported by grants from National Heart, Lung, and Blood Institute (HL‐65998,HL‐111775).

Neck Kaposiform haemangioendothelioma in a Fischer’s lovebird (Agapornis fischeri)

A six-year-old female Fischer's lovebird (Agapornis fischeri) presented at necropsy with a cutaneous mass on the neck, 3.5cm in diameter, yielding and with blood content. Histopathological findings showed a neoplasm characterized by proliferation of vascular endothelial cells. The histology of the mass revealed a multinodular, focally infiltrating tumor. Deeper dermal nodules were made of spindle cells forming vascular slits reminiscent of the histology seen in Kaposi's sarcoma (KS). More superficially located dermal nodules consisted of small blood vessels, with histology resembling capillary hemangioma. The spindle cells and capillaries were strongly positive for Vimentin, endothelial cell marker CD31, and negative for sarcomeric α-smooth muscle actin (α-SMA). Intravascular platelet trapping and Periodic acid-Schiff (PAS)-positive hyaline globules were also observed. Differential diagnosis included Kaposi's sarcoma, capillary haemangioma, spindle cell haemangioendothelioma, and epithelioid haemangioendothelioma. Based on morphological and immunohistochemical findings, the tumor was diagnosed as a cutaneous Kaposiform haemangioendothelioma (KHE), a rare, low-grade malignant vascular neoplasm. Other organs showed no abnormalities. PCR amplifications, conducted using Kaposi's sarcoma-associated herpesvirus (KSHV)-specific primers and degenerate sets of primers designed to detect and characterize members of the Herpesviridae, on DNA extracted from tumor tissue and from whole blood failed to amplify any KSHV-related sequence. Moreover, no specific signal was obtained using primers for detection of psittacine herpesvirus, known to be linked to Pacheco's disease in parrots. To the best of our knowledge, this unusual case is the third report of KHE in a non-human animal species, the first described in a bird.

Markers of fibroblast-rich tumor stroma and perivascular cells in serous ovarian cancer: Inter- and intra-patient heterogeneity and impact on survival.

Inter- and intra-patient variations in tumor microenvironment of serous ovarian cancer are largely unexplored. We aimed to explore potential co-regulation of tumor stroma characteristics, analyze their concordance in primary and metastatic lesions, and study their impact on survival. A tissue microarray (TMA) with 186 tumors and 91 matched metastases was subjected to immunohistochemistry double staining with endothelial cell marker CD34 and fibroblast and pericyte markers α-SMA, PDGFβR and desmin. Images were digitally analyzed to yield “metrics” related to vasculature and stroma features.Intra-case analyses showed that PDGFβR in perivascular cells and fibroblasts were strongly correlated. Similar findings were observed concerning α-SMA. Most stroma characteristics showed large variations in intra-case comparisons of primary tumors and metastasis. Large PDGFβR-positive stroma fraction and high PDGFβFR positive perivascular intensity were both significantly associated with shorter survival in uni- and multi-variate analyses (HR 1.7, 95% CI 1.1-2.5; HR 1.7, 95% CI 1.1-2.8).In conclusion, we found PDGFβR- and α-SMA-expression to be largely independent of each other but concordantly activated in perivascular cells and in fibroblasts within the primary tumor. Stromal characteristics differed between primary tumors and metastases. PDGFβR in perivascular cells and in fibroblasts may be novel prognostic markers in serous ovarian cancer.

Neurotrophin-3 Induces BMP-2 and VEGF Activities and Promotes the Bony Repair of Injured Growth Plate Cartilage and Bone in Rats.

Injured growth plate is often repaired by bony tissue causing bone growth defects, for which the mechanisms remain unclear. Because neurotrophins have been implicated in bone fracture repair, here we investigated their potential roles in growth plate bony repair in rats. After a drill-hole injury was made in the tibial growth plate and bone, increased injury site mRNA expression was observed for neurotrophins NGF, BDNF, NT-3, and NT-4 and their Trk receptors. NT-3 and its receptor TrkC showed the highest induction. NT-3 was localized to repairing cells, whereas TrkC was observed in stromal cells, osteoblasts, and blood vessel cells at the injury site. Moreover, systemic NT-3 immunoneutralization reduced bone volume at injury sites and also reduced vascularization at the injured growth plate, whereas recombinant NT-3 treatment promoted bony repair with elevated levels of mRNA for osteogenic markers and bone morphogenetic protein (BMP-2) and increased vascularization and mRNA for vascular endothelial growth factor (VEGF) and endothelial cell marker CD31 at the injured growth plate. When examined in vitro, NT-3 promoted osteogenesis in rat bone marrow stromal cells, induced Erk1/2 and Akt phosphorylation, and enhanced expression of BMPs (particularly BMP-2) and VEGF in the mineralizing cells. It also induced CD31 and VEGF mRNA in rat primary endothelial cell culture. BMP activity appears critical for NT-3 osteogenic effect in vitro because it can be almost completely abrogated by co-addition of the BMP inhibitor noggin. Consistent with its angiogenic effect in vivo, NT-3 promoted angiogenesis in metatarsal bone explants, an effect abolished by co-treatment with anti-VEGF. This study suggests that NT-3 may be an osteogenic and angiogenic factor upstream of BMP-2 and VEGF in bony repair, and further studies are required to investigate whether NT-3 may be a potential target for preventing growth plate faulty bony repair or for promoting bone fracture healing. © 2016 American Society for Bone and Mineral Research.

Novel method to improve vascularization of tissue engineered constructs with biodegradable fibers

Tissue engineered grafts lack adequate vascularization and suffer from poor perfusion in vivo curtailing clinical application. Improving vascularization in any tissue implants would hence increase their survivability and treatment efficacy. Many prevascularization strategies established to date involves the angiogenic induction of endothelial progenitor cells in thick tissue engineered scaffolds to obtain vascularization. These 3D scaffolds typically require a dynamic cell culturing system involving/needful of bioreactors to obtain vascularization in thick tissue engineered scaffolds. Herein, we developed a novel method to engineer a vessel network without bioreactor, where 3D blood vessels could be simply obtained in a 2D static cell culturing system. This network could be used to augment the prevascularization of tissue engineered grafts. Endothelial cells (HUVECs) were confluently cultured on resorbable electrospun poly (D, L-lactide-co-glycolide) microfibers of capillary dimensions. These cell encapsulated capillary fibers were further embedded in collagen with HUVECs and vascular endothelial growth factor. Green fluorescent protein and red fluorescent protein expressing HUVECs were used to label cells on fiber and in collagen respectively for visualization and monitoring of capillary network formation. Seeded HUVECs in the hybrid construct were subsequently cultured for 30 days before implantation. Vessel density was measured by the total tubule length per unit area at different time points. In vitro results indicated that the fibers provide contact guidance to form primary networks to direct more vessels branching of HUVECs in hybrid constructs and the vessel integrity of microvasculature was retained after fiber degradation. In addition, these preformed engineered capillaries could capably inosculate with de novo capillaries in collagen when combined, giving rise to a hybrid pre-vascularized scaffold of more extensive vessel network and interconnections, thereby markedly improved prevascularization. When implanted onto the dorsal skin of immune-deficient mice, vessels of hybrid pre-vascularized scaffold also rapidly anastomosed with mice vasculature within a day as confirmed with the immunostaining of endothelial cell markers CD31 and von Willebrand factor. This proof of concept study showed that artificial capillaries formed through contact guidance of endothelial cells on resorbable capillary sized microfibers can significantly enhance prevascularization in tissue engineered constructs intended for surgical implantation.

Impaired angiogenesis in the enalapril-treated neonatal rat kidney.

PurposeNephrogenesis is normally accompanied by a tightly regulated and efficient vascularization. We investigated the effect of angiotensin II inhibition on angiogenesis in the developing rat kidney.MethodsNewborn rat pups were treated with enalapril (30 mg/kg/day) or vehicle (control) for 7 days after birth. Renal histological changes were checked using Hematoxylin & Eosin staining. We also investigated the intrarenal expression of vascular endothelial growth factor (VEGF)-A, VEGF receptor 1 (VEGFR1), VEGFR2, platelet-derived growth factor (PDGF)-B, and PDGF receptor-β with Western blotting and immunohistochemical staining at postnatal day 8. Expression of the endothelial cell marker CD31 was examined to determine glomerular and peritubular capillary density.ResultsEnalapril-treated rat kidneys showed disrupted tubules and vessels when compared with the control rat kidneys. In the enalapril-treated group, intrarenal VEGF-A protein expression was significantly higher, whereas VEGFR1 protein expression was lower than that in the control group (P<0.05). The expression of VEGFR2, PDGF-B, and PDGF receptor-β was not different between the 2 groups. The increased capillary CD31 expression on the western blots of enalapril-treated rat kidneys indicated that the total endothelial cell protein level was increased, while the cortical capillary density, assessed using CD31 immunohistochemical staining, was decreased.ConclusionImpaired VEGF-VEGFR signaling and altered capillary repair may play a role in the deterioration of the kidney vasculature after blocking of angiotensin II during renal development.

Vasculogenic Mimicry in Prostate Cancer: The Roles of EphA2 and PI3K.

BACKGROUND. Aggressive tumor cells can form perfusable networks that mimic normal vasculature and enhance tumor growth and metastasis. A number of molecular players have been implicated in such vasculogenic mimicry, among them the receptor tyrosine kinase EphA2, which is aberrantly expressed in aggressive tumors. Here we study the role and regulation of EphA2 in vasculogenic mimicry in prostate cancer where this phenomenon is still poorly understood.METHODS. Vasculogenic mimicry was characterized by tubules whose cellular lining was negative for the endothelial cell marker CD34 but positive for periodic acid-Schiff staining, and/or contained red blood cells. Vasculogenic mimicry was assessed in 92 clinical samples of prostate cancer and analyzed in more detail in three prostate cancer cell lines kept in three-dimensional culture. Tissue samples and cell lines were also assessed for total and phosphorylated levels of EphA2 and its potential regulator, Phosphoinositide 3-Kinase (PI3K). In addition, the role of EphA2 in vasculogenic mimicry and in cell migration and invasion were investigated by manipulating the levels of EphA2 through specific siRNAs. Furthermore, the role of PI3K in vasculogenic mimicry and in regulating EphA2 was tested by application of an inhibitor, LY294002.RESULTS. Immunohistochemistry of prostate cancers showed a significant correlation between vasculogenic mimicry and high expression levels of EphA2, high Gleason scores, advanced TNM stage, and the presence of lymph node and distant metastases. Likewise, two prostate cancer cell lines (PC3 and DU-145) formed vasculogenic networks on Matrigel and expressed high EphA2 levels, while one line (LNCaP) showed no vasculogenic networks and lower EphA2 levels. Specific silencing of EphA2 in PC3 and DU-145 cells decreased vasculogenic mimicry as well as cell migration and invasion. Furthermore, high expression levels of PI3K and EphA2 phosphorylation at Ser897 significantly correlated with the presence of vasculogenic mimicry and in vitro inhibition of PI3K by LY294002 disrupted vasculogenic mimicry, potentially through a reduction of EphA2 phosphorylation at Ser897.CONCLUSIONS. The expression levels of PI3K and EphA2 are positively correlated with vasculogenic mimicry both in vivo and in vitro. Moreover, phosphorylation levels of EphA2 regulated by PI3K are also significantly associated with vasculogenic mimicry in vivo. Based on its functional implication in vasculogenic mimicry in vitro, EphA2 signaling may be a potential therapeutic target in advanced prostate cancer.

IMPS-02EXPRESSION OF MULTIPLE ANTIGENS IN INDIVIDUAL GLIOBLASTOMA PATIENT SAMPLES EVALUATED BY IMMUNOCHEMISTRY

Cellular heterogeneity is a hallmark characteristic of ostensibly similar cell populations occurring during neural and glial development, and during tumorigenesis and tumor progression. For the latter case, large collections of formalin-fixed paraffin embedded (FFPE) clinical specimens are a valuable resource for evaluating gene expression across large study cohorts. Many of these patient samples consist of serial tumor sections each stained for a single antigen by chromogenic immunohistochemistry (IHC), as is standard clinical pathology practice. Quantifying multiple tumor related antigens in the context of GBM tissue is an essential step towards understanding the fundamental biology of these tumors as well as developing novel targeted therapies. Towards this end, we have developed methods for combining semi-quantitative analysis of IHC processed tumor sections with regional annotation by a clinical pathologist. This has allowed us to consider patterns of antigen co-expression as well as spatial relationships with tumor structures and physiological status. We will present our observations on expression of tumor-associated antigens IL13Rα2, HER2 and EGFR, and associations with proliferation as indicated by Ki67 expression and the vasculature as marked by the endothelial cell marker CD34.

Increased angiogenesis and VEGF expression correlates with disease severity in prurigo patients.

Vascular endothelial growth factor-A (VEGF-A) is known as the major skin angiogenesis factor and can be produced by various resident skin cells including keratinocytes. To identify and characterize the role of VEGF-A in the pathogenesis of prurigo. Expression of VEGF, VEGFR2, CD-31, and D2-40 was analyzed in the skin of eleven prurigo patients and seven healthy controls by immunohistochemistry. VEGF immunoreactivity (IR) was markedly increased in the epidermis, dermis and subcutis of prurigo patients, whereas expression of the main receptor for VEGF-A in the skin, VEGFR2, was comparable to that of healthy controls. The increased VEGF expression in the skin was associated with a marked increase in the number (12.8 ± 2.1 vs 5.6 ± 0.5, P < 0.05) but not in the size of blood vessels, as assessed by staining of the endothelial cell marker CD31. This increase in small blood vessels correlated closely with increases in the epidermal thickness in prurigo lesions. The number of lymphatic vessels as assessed by D2-40 staining was found to be similar in prurigo patients and healthy controls. Based on these findings, we speculate that the observed profound vascular remodelling in prurigo might contribute to the pathogenesis of prurigo and the corresponding clinical symptoms and that targeting of VEGF may present a novel therapeutic strategy in the treatment of prurigo patients.

Physical Activity and Prostate Tumor Vessel Morphology: Data from the Health Professionals Follow-up Study.

Vigorous activity is associated with lower risk of prostate cancer progression, but the biologic mechanisms are unknown. Exercise affects vascularization of tumors in animal models, and small, irregularly shaped vessels in prostate tumors are associated with fatal prostate cancer. We hypothesized that men who engaged in vigorous activity or brisk walking would have larger, more regularly shaped vessels in their prostate tumors. We prospectively examined whether physical activity was associated with prostate tumor microvessel morphology among 571 men in the Health Professionals Follow-up Study using ordinal logistic regression. Vessel size (μm(2)), vessel lumen regularity (perimeter(2)/4 · Π · area), and microvessel density (number/high-powered field) were ascertained in tumor sections stained for endothelial cell marker CD34. Vigorous activity [metabolic equivalent task (MET) ≥ 6], nonvigorous activity (MET < 6), and walking pace were assessed a median of 14 months before diagnosis. Prostate tumors from men who reported a brisk walking pace (3+ mph) had larger, more regularly shaped blood vessels compared with those of men who walked at a less than brisk pace [vessel regularity OR, 1.59; 95% confidence interval (CI), 1.11-2.27; P value, 0.01; vessel size OR, 1.48; 95% CI, 1.04-2.12; P value, 0.03]. Brisk walking was not associated with microvessel density; total vigorous and nonvigorous activities were not associated with vessel size, shape, or number. Brisk walking may be associated with larger, more regularly shaped vessels in prostate tumors. Additional research elucidating the effect of physical activity on prostate tumor biology is needed.

Experimental study of real-time monitoring of glioma stem cell differentiation process

Objective To observe the changes in a variety of molecular markers in the differentiation process from glioma stem cells to endothelial cells using live cell fluorescence imaging technique. Methods Live cell fluorescence imaging technique was used to study the differentiation process of glioma stem cell GSC-1 for dynamic observation of 12 h. The immunofluorescence staining was used to perform endothelial cell surface marker CD34 staining during the three dimensional culture at 0, 2, and 6 h, and the morphological changes of GSC-1 were observed by light microscopy. Results Under the three-dimensional culture, GSC-1 cells could form tube-like structures. The number of some cells expressed endothelial cell markers CD34, CD34 positive cells increased with the time of differentiation (P<0.05), while stem marker disappeared gradually. Live cell fluorescence imaging observed that the number of CD34 positive cells increased with the time of induction and differentiation under the same field of vision. The whole process of a single GSC-1 cell transformed from a CD34 negative cell to a CD34 positive cell was observed. Conclusions The live cell fluorescence imaging technique detecting the cell differentiation process can get the same result of the traditional immunofluorescence assay, and it is more intuitive and accurate. It can follow up and observe a single cell for a long time. Key words: Glioma; Glioblastoma; Neoplastic stem cells; Cell differentiation

Myofibroblasts in proliferative diabetic retinopathy can originate from infiltrating fibrocytes and through endothelial‐to‐mesenchymal transition (EndoMT)

PurposeThe fibrovascular epiretinal membranes from patients with proliferative diabetic retinopathy (PDR) are characterized by the accumulation of a large number of myofibroblasts. We explored the hypothesis that proliferating endothelial cells via endothelial‐to‐mesenchymal transition (EndoMT) and/or bone marrow‐derived circulating fibrocytes contribute to the myofibroblast population present in PDR membranes.MethodsEpiretinal membranes from 14 patients with PDR were studied by immunohistochemistry. In addition, we investigated the phenotypic changes that take place in human retinal microvascular endothelial cells following exposure to transforming growth factor‐β1 (TGF‐ β1), connective tissue growth factor (CTGF) and the proinflammatory cytokines interleukin‐1β (IL‐1β) and tumor necrosis factor‐a (TNF‐a).ResultsAll membranes contained neovessels expressing the endothelial cell marker CD31. CD31+ endothelial cells co‐expressed the fibroblast/myofibroblast markers fibroblast‐specific protein‐1 (FSP‐1) and a‐SMA, indicative for the occurrence of endoMT. In the stroma, cells expressing FSP‐1, a‐SMA, the leukocyte common antigen CD45, and the myelomonocytic marker CD11b were detected. Double labeling showed co‐localization of CD45 with FSP‐1 and a‐SMA and co‐localization of CD11b with a‐SMA and matrix metalloproteinase‐9, demonstrating the presence of infiltrating fibrocytes. Retinal microvascular endothelial cells changed morphology upon cytokine exposure, lost the expression of endothelial cell markers (endothelial nitric oxide synthase and vascular endothelial‐cadherin) and started to express mesenchymal markers (calponin, snail, transgelin and FSP‐1).ConclusionsThese results suggest that endothelial cells as well as circulating fibrocytes may differentiate into myofibroblasts in the diabetic eye and contribute to pathologic fibrosis in PDR.

Myofibroblasts in proliferative diabetic retinopathy can originate from infiltrating fibrocytes and through endothelial‐to‐mesenchymal transition (EndoMT)

PurposeThe fibrovascular epiretinal membranes from patients with proliferative diabetic retinopathy (PDR) are characterized by the accumulation of a large number of myofibroblasts. We explored the hypothesis that proliferating endothelial cells via endothelial‐to‐mesenchymal transition (EndoMT) and/or bone marrow‐derived circulating fibrocytes contribute to the myofibroblast population present in PDR membranes.MethodsEpiretinal membranes from 14 patients with PDR were studied by immunohistochemistry. In addition, we investigated the phenotypic changes that take place in human retinal microvascular endothelial cells following exposure to transforming growth factor‐β (TGF‐β1), connective tissue growth factor (CTGF) and the proinflammatory cytokines interleukin‐1β (IL‐1β) and tumor necrosis factor‐a (TNF‐a).ResultsAll membranes contained neovessels expressing the endothelial cell marker CD31. CD31+ endothelial cells co‐expressed the fibroblast/myofibroblast markers fibroblast‐specific protein‐1 (FSP‐1) and a‐SMA, indicative for the occurrence of endoMT. In the stroma, cells expressing FSP‐1, a‐SMA, the leukocyte common antigen CD45, and the myelomonocytic marker CD11b were detected. Double labeling showed co‐localization of CD45 with FSP‐1 and a‐SMA and co‐localization of CD11b with a‐SMA and matrix metalloproteinase‐9, demonstrating the presence of infiltrating fibrocytes. Retinal microvascular endothelial cells changed morphology upon cytokine exposure, lost the expression of endothelial cell markers (endothelial nitric oxide synthase and vascular endothelial‐cadherin) and started to express mesenchymal markers (calponin, snail, transgelin and FSP‐1).ConclusionsThese results suggest that endothelial cells as well as circulating fibrocytes may differentiate into myofibroblasts in the diabetic eye and contribute to pathologic fibrosis in PDR.

Multi-lineage potential research of bone marrow mesenchymal stem cells from Bama miniature pig.

Bone marrow mesenchymal stem cells (BMSCs) are easy to obtain and thought to be ideal candidate cells for reconstruction of tissues and organs. Pigs are an appropriate animal model because their physiological structure, organ size, nutritional metabolism, and pathological reactions are similar to those of humans. In this study, bone marrow was collection from Bama miniature pigs to isolate BMSCs (B-BMSCs) by whole bone marrow culture method. We then examined their biological characteristics such as growth kinetics, surface antigen, and multi-lineage potential. B-BMSCs could be cultured for 36 passages in vitro. Growth kinetics and colony forming assay analyses indicated that B-BMSCs had a strong capacity for self-renewal in vitro and their proliferation rate appeared to decrease with passaging. These findings were supported by the animal cytophysiology in vitro. Surface antigen detection showed that B-BMSCs expressed CD29, CD44, CD71, CD73, and CD90, but not the endothelial cell marker CD31 or hematopoietic cell-specific marker CD34. This result was consistent with the characteristics of B-BMSCs. Furthermore, under appropriate conditions for multidirectional differentiation, B-BMSCs were induced to differentiate into adipocytes, osteoblasts, neuron-like cells, islet cells, liver-like cells, and endothelial cells as indicated by reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. These results verified the differentiation potential of B-BMSCs. In this study, B-BMSCs were isolated from Bama miniature pigs, and the self-renewal ability and differential potential was evaluated in vitro. The present study has important bearing on the potential application of B-BMSCs as a stem cell source for regenerative therapies. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 671-685, 2015. © 2015 Wiley Periodicals, Inc.

Abstract 1376: Receptor tyrosine kinase (RTK) signaling pathway in preclinical thyroid cancer models: Antitumor and antiangiogenic activity of lenvatinib to target VEGFR/FGFR/RET

Abstract Background: Inhibition of tumor angiogenesis through the vascular endothelial growth factor receptor (VEGFR) signaling and oncogenic RTK signaling is a promising therapeutic target in thyroid cancer. Lenvatinib mesilate (LEN) is the selective inhibitor of VEGFR1-3, and other proangiogenic and oncogenic pathway-related RTKs including fibroblast growth factor receptors (FGFR1-4), the platelet-derived growth factor receptor (PDGFR) α, KIT, and RET. We studied the antitumor and antiangiogenic activity of LEN by using various thyroid cancer models. Methods: Roles of RTK signaling pathways in 11 thyroid cancer (differentiated (DTC), medullary (MTC), and anaplastic (ATC)) cells were examined by testing antiproliferative activity of selective RTK inhibitors. Mutation profiling of DTC cells was done by MassARRAY systems. Antitumor and antiangiogenic (immunohistochemical staining of the endothelial cell marker CD31) activity of LEN was tested in s.c. xenograft models. Phosphorylation of molecules in the FGFR1 and RET signaling pathways was evaluated through Western blotting (WB). Pharmacodynamic (PD) biomarker analyses of VEGF and FGF signaling pathway in xenograft models by treatment of LEN were performed. Results: DTC: Molecular profiling in DTC cells showed K1 cells had BRAF V600E and PIK3CA mutation (E542K). Other DTC cells didn't have active tumor driver mutations. Among 5 DTC cells, only RO82-W-1 (W1) cell showed the selective sensitivity against LEN and FGFR selective inhibitors (PD166866 and PD173074). W1 cells overexpressed FGFR1 and LEN inhibited bFGF-induced phosphorylation of FGFR1, FRS2, MEK and ERK in W1 cells in vitro. LEN inhibited in vivo tumor growth and decreased microvessel density (MVD) in 5 human DTC xenografts. LEN decreased phosphorylation of FRS2, which a substrate FGFR, in W1 xenografts. MTC: TT cells were reported to have activated mutation in RET. The IC50 value of LEN was 0.078 μM. Oral administration of LEN at dose of 10, 30 and 100 mg/kg inhibited in vivo tumor growth but did not decrease MVD in TT xenograft model. LEN inhibited phosphorylation of RET within TT xenograft at the same doses to show antitumor activity. ATC: LEN did not show anti proliferative activity against 5 ATC cells in vitro (IC50 value &amp;gt; 10 μM). LEN showed the both antitumor and antiangiogenic activity in 5 ATC xenografts. Conclusion: LEN showed the antitumor activity in 11 human thyroid cancer xenografts through antiangiogenic activity based on inhibition of VEGFR2 whereas inhibition of FGFR and RET signaling pathway contributes antitumor activity of LEN in some of DTC and MTC preclinical models. These data suggest that LEN provides therapeutic benefits in various human thyroid cancer models through VEGFR/FGFR/RET inhibitory activity. Citation Format: Osamu Tohyama, Junji Matsui, Kotaro Kodama, Naoko Hata Sugi, Takayuki Kimura, Kiyoshi Okamoto, Yukinori Minoshima, Masao Iwata, Yasuhiro Funahashi. Receptor tyrosine kinase (RTK) signaling pathway in preclinical thyroid cancer models: Antitumor and antiangiogenic activity of lenvatinib to target VEGFR/FGFR/RET. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1376. doi:10.1158/1538-7445.AM2015-1376

Abstract 4071: Cancer stem cell-induced vascularization of skin cancer tumors

Abstract Our previous studies identify a subpopulation of epidermal cancer stem (ECS) cells in human squamous cell carcinoma that are efficient tumor formers. These cells display enhanced invasion and migration, and form large, invasive and highly aggressive tumors. We now show that ECS cells produce highly vascularized tumors. This is confirmed visually and by detection of increased expression of the CD31 endothelial cell marker. To understand the molecular basis for increased vascularization, we assayed for ECS cell and non-stem cancer cell production of angiogenic factors. Pro-angiogenic factors, including VEGF-A, HIF-1α and MMP9, are produced at high level in ECS cell-derived tumors, as compared to non-stem cancer cell tumors. In addition, anti-angiogenic factor production (thrombospondin-1, endothelin-1, serpin B5) is reduced. This is consistent with the finding that ECS cell tumor extracts more efficiently stimulate HUVEC cell tube formation. Moreover, these ECS tumor-derived cells display enhanced spheroid formation, and cell migration and invasion. Knockdown of VEGF-A or VEGFR2, or treatment with anti-VEGF-A attenuates these events. In addition, treatment with bevacizumab (anti-VEGF-A) suppresses tumor formation in vivo. These studies suggest that the VEGF-A signaling pathway is enhanced in ECS cells and is in part responsible the ability of these cells to form aggressive and highly vascularized tumors. Citation Format: Dan Grun, Gautam Adhikary, Richard Eckert. Cancer stem cell-induced vascularization of skin cancer tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4071. doi:10.1158/1538-7445.AM2015-4071

Receptors for advanced glycation end products (RAGE) is associated with microvessel density and is a prognostic biomarker for clear cell renal cell carcinoma.

The receptor for advanced glycation end products (RAGE) is involved in a variety of biological processes, including tumorigenisis. Previous studies have demonstrated that RAGE regulates the neo-angiogenesis related downstream molecule-vascular endothelial growth factor receptor 2 (VEGFR-2). Here, we investigated the potential relationship between RAGE, VEGFR-2 and angiogenesis in 80 renal cell carcinoma (RCC) patients. Real-time quantitative PCR and ELISA analysis were used to explore the RAGE and VEGFR-2 gene expression levels and the protein of VEGFR-2 expression. Meanwhile, angiogenesis was detected by the semi-quantification of endothelial cell marker CD34 combined with caldesmon, which was detected by microvessel density (MVD) technique and immunohistochemistry. Tumors were classified as low or high RAGE-expressing using the median as the cut-off. Immunofluorescence staining for RAGE protein was performed as well. Additionally, the median gene expression levels of VEGFR-2 in the tumors were significantly lower expressing low levels of RAGE expression, 0.34 (95% CI, 0.28-0.39) compared to the expressing high levels of RAGE expression, 0.45 (95% CI, 0.29-0.61), (P=0.03). The median MVD was significantly lower in the tumors expressing low levels of RAGE, 6.5 (95% CI, 6.21-7.43), compared to the expressing high levels, 7.9 (95% CI, 6.25-8.93), (P<0.01). Further, a positive association was certified with VEGFR-2 protein levels, P=0.07. Besides, RCC with high levels of RAGE expression are associated with high VEGFR-2 mRNA/protein levels and a higher density of microvessels; conversely, Kaplan-Meier survival analysis suggests that a significant correlation of elevated RAGE expression with decreased overall survival and metastasis-free survival. Our results establish that RAGE was identified as a potential prognostic biomarker for disease prognosis of RCC.

Mo1714 Analysis of the Protease MT1-MMP As Therapeutic Target in IBD

Background: We have recently demonstrate higher levels of the MT1-MMP by qPCR -in biopsiesand higher levels of its substrates thrombospondin-1 (TSP1) and nidogen-1 (NID1) -in serumfrom patients of inflammatory bowel disease (IBD), a chronic disorder involving inflammation and angiogenesis. Our objective was analysing the functional role of MT1MMP in the angiogenesis and damage produced in IBD. Methods: Gene expression of MT1MMP was detected by qPCR in biopsies, and TNFα, VEGFA, TSP1, NID1 levels were quantified by ELISA in serum from patients with active ulcerative colitis (UC) or Crohn's disease (CD). Clinical IBD activity was assessed respectively by the Mayo score for UC, and by the Harvey-Bradshaw index for CD. Endoscopic activity was determined with the Mayo subscore and the SES-CD index. MT1-MMP, TSP1 and NID1 expression and the angiogenic response were also analyzed by immunostaining (IF) in colonic sections from controls or patients affected by IBD. Besides, we used a mouse model of dextran sulphate sodium (DSS)induced colitis to analysed the angiogenic response by IF with the specific endothelial cell markers CD31, VE cadherin, and the expression of MT1-MMP, and its substrates TSP1 and NID1 by IF of histological colon sections from either control mice or mice treated with 1% DSS (moderate colitis) or 4% DSS (severe colitis), in wild type mice. The endothelial MT1MMP expression was also analysed in MT1-MMPLacZ/+ mice. Finally, the in vivo functional analysis was done in mice with endothelium-specific deletion of MT1-MMP generated by (MT1-MMPflox/floxxVECadhERT2-Cre) breeding analyzing: (i) colitis score; (ii) vascular pattern quantifying, perfusion, endothelial proliferation and colonic hypoxia (injection and stainings of isolectinB4, EdU, and Pimonidazole); and (iii) inflammatory infiltrate (IF with CD11b). Results: MT1-MMP expression was higher in biopsies of patients with active IBD, moreover, serum levels of TSP-1 and NID1 were significantly increased in UC and CD patients with low activity. In the mouse colitis model, serum levels of TNFα, VEGF-A, TSP1 y NID1 and MT1-MMP expression in intestinal tissues, were increased along the progression of the mouse disease, as well as the angiogenesis in the intestinal mucosa. Our preliminary results indicate that the absence of MT1-MMP in EC protects from IBD, through a vascular normalization (reestablishment of structure and function of blood vessels), with the consequent decrease of colonic hypoxia and inflammation. Conclusions: These data support the potential use of TSP1 and NID1 as biomarkers in the diagnostic of pre-symptomatic or low activity IBD, aiming the endothelial MT1-MMP as a new therapeutic target for normalization of vasculature and improve the symptoms in IBD.

Mo1715 The Effect of Lymphocyte Function Associated Antigen-1 on Inflammatory Bowel Disease by Regulating Treg Cells

Background: We have recently demonstrate higher levels of the MT1-MMP by qPCR -in biopsiesand higher levels of its substrates thrombospondin-1 (TSP1) and nidogen-1 (NID1) -in serumfrom patients of inflammatory bowel disease (IBD), a chronic disorder involving inflammation and angiogenesis. Our objective was analysing the functional role of MT1MMP in the angiogenesis and damage produced in IBD. Methods: Gene expression of MT1MMP was detected by qPCR in biopsies, and TNFα, VEGFA, TSP1, NID1 levels were quantified by ELISA in serum from patients with active ulcerative colitis (UC) or Crohn's disease (CD). Clinical IBD activity was assessed respectively by the Mayo score for UC, and by the Harvey-Bradshaw index for CD. Endoscopic activity was determined with the Mayo subscore and the SES-CD index. MT1-MMP, TSP1 and NID1 expression and the angiogenic response were also analyzed by immunostaining (IF) in colonic sections from controls or patients affected by IBD. Besides, we used a mouse model of dextran sulphate sodium (DSS)induced colitis to analysed the angiogenic response by IF with the specific endothelial cell markers CD31, VE cadherin, and the expression of MT1-MMP, and its substrates TSP1 and NID1 by IF of histological colon sections from either control mice or mice treated with 1% DSS (moderate colitis) or 4% DSS (severe colitis), in wild type mice. The endothelial MT1MMP expression was also analysed in MT1-MMPLacZ/+ mice. Finally, the in vivo functional analysis was done in mice with endothelium-specific deletion of MT1-MMP generated by (MT1-MMPflox/floxxVECadhERT2-Cre) breeding analyzing: (i) colitis score; (ii) vascular pattern quantifying, perfusion, endothelial proliferation and colonic hypoxia (injection and stainings of isolectinB4, EdU, and Pimonidazole); and (iii) inflammatory infiltrate (IF with CD11b). Results: MT1-MMP expression was higher in biopsies of patients with active IBD, moreover, serum levels of TSP-1 and NID1 were significantly increased in UC and CD patients with low activity. In the mouse colitis model, serum levels of TNFα, VEGF-A, TSP1 y NID1 and MT1-MMP expression in intestinal tissues, were increased along the progression of the mouse disease, as well as the angiogenesis in the intestinal mucosa. Our preliminary results indicate that the absence of MT1-MMP in EC protects from IBD, through a vascular normalization (reestablishment of structure and function of blood vessels), with the consequent decrease of colonic hypoxia and inflammation. Conclusions: These data support the potential use of TSP1 and NID1 as biomarkers in the diagnostic of pre-symptomatic or low activity IBD, aiming the endothelial MT1-MMP as a new therapeutic target for normalization of vasculature and improve the symptoms in IBD.

P-Hydroxybenzyl alcohol-containing biodegradable nanoparticle improves functional blood flow through angiogenesis in a mouse model of hindlimb ischemia

Therapeutic angiogenesis has achieved promising results for ischemic diseases or peripheral artery disease in preclinical and early-phase clinical studies. We examined the therapeutic angiogenic effects of HPOX, which is biodegradable polymer composing the antioxidant p-hydroxybenzyl alcohol (HBA), in a mouse model of hindlimb ischemia. HPOX effectively stimulated blood flow recovery, compared with its degraded compounds HBA and 1,4-cyclohexendimethanol, via promotion of capillary vessel density in the ischemic hindlimb. These effects were highly correlated with levels of angiogenic inducers, vascular endothelial cell growth factor (VEGF), heme oxygenase-1 (HO-1), and Akt/AMPK/endothelial nitric oxide synthase (eNOS) in ischemic mouse hindlimb muscle. Blood perfusion and neovascularization induced by HPOX were reduced in eNOS−/− and HO-1+/− mice. HPOX also elevated the endothelial cell markers VEGF receptor-2, CD31, and eNOS mRNAs in the ischemic hindlimb, indicating that HPOX increases endothelial cell population and angiogenesis in the ischemic muscle. However, this nanoparticle suppressed expression levels of several inflammatory genes in ischemic tissues. These results suggest that HPOX significantly promotes angiogenesis and blood flow perfusion in the ischemic mouse hindlimb via increased angiogenic inducers, along with suppression of inflammatory gene expression. Thus, HPOX can be used potentially as a noninvasive drug intervention to facilitate therapeutic angiogenesis.