Involvement of integrin-linked kinase in capillary/tube-like network formation of human vascular endothelial cells

Injectable anti-cancer drug loaded silk-based hydrogel for the prevention of cancer recurrence and post-lumpectomy tissue regeneration aiding triple-negative breast cancer therapy

A single system capable of delivering anticancer drugs and growth factors by a minimally invasive approach is in demand for effective treatment of triple-negative breast cancer (TNBC) after lumpectomy. Here, we showcase one such holistic system for TNBC therapy and its assessment via 3D in vitro lumpectomy model, a first of its kind. Firstly, Bombyx mori silk fibroin (BMSF) and Antheraea assamensis silk fibroin (AASF) blended hydrogels were prepared and biophysically characterized. Secondly, a 3D in vitro lumpectomy model was developed using MDA-MB-231 cell line to assess the efficacy of localized delivery of doxorubicin (dox) using injectable hydrogel system in terminating remaining breast cancer after lumpectomy. Additionally, we have also evaluated the adipose tissue regeneration in the lumpectomy region by delivering dexamethasone (dex) using injectable hydrogels. Rheological studies showed that the BMSF/AASF blended hydrogels exhibit viscoelasticity and injectability conducive for minimally invasive application. The developed hydrogels by virtue of its slow and sustained release of dox exerted cytotoxicity towards MDA-MB-231 cells assessed through in vitro studies. Further, dex loaded hydrogel supported adipogenic differentiation of adipose tissue derived stem cells (ADSCs), while the secreted factors were found to aid in vascularization and macrophage polarization. This was confirmed through in vitro angiogenic tube formation assay and macrophage polarization study respectively. The corroborated results vouch for potential application of this injectable hydrogels for localized anticancer drug delivery and aiding in breast reconstruction, post lumpectomy.

Design, Fabrication, and Evaluation of Polyglycolic Acid Modules with Canals as Tissue Elements in Cellular-Assembly Technology

The aim of the present study was to design and fabricate polyglycolic acid (PGA) modules on the basis of the Raschig ring as a tissue element for bottom–top tissue engineering to increase the feasibility of cellular-assembly technology. Three types of modules, namely, cylindrical, Raschig ring, and transverse-pore modules, with different numbers and orientations of canals, were designed and fabricated by modified selective-laser-sintering (SLS) technology. These modules maintained their structure in a flowing culture environment, and degradation did not create an acidic environment, hence promoting their ability to scale up to highly functional tissue. The modules were seeded with human hepatoma Hep G2 cells and cultured for 10 days. The transverse-pore modules were found to have the highest glucose consumption, albumin production, and cell viability among the three tested modules. Our study showed that the proposed module design provided better mass transfer and possessed the required mechanical strength to enable use in the construction of large tissue.

Paris Saponin II suppresses the growth of human ovarian cancer xenografts via modulating VEGF-mediated angiogenesis and tumor cell migration

PURPOSE

Paris Saponin II (PSII) is an active component of Rhizoma Paridis-an essential ingredient in traditional Chinese herbal medicines. PSII can induce cytotoxic effects in cancer cells and inhibit ovarian cancer growth. Since pathological angiogenesis (henceforth, angiogenesis) is often associated with gynecological cancers, here, we investigated whether PSII renders effects on angiogenesis and examined possible molecular mechanisms underlying the effects of PSII.

METHODS

The effects of PSII on the biofunctions of endothelial cells (EC), the crucial components of blood vessels, were examined by standardized angiogenesis in vitro and ex vivo assays, Western blot analysis, ELISA, and kinase assay. Angiogenesis in a xenograft mouse model of ovarian cancer was evaluated by color Doppler ultrasound and immunohistochemistry.

RESULTS

PSII exerted marked inhibitory effect on the growth of VEGF-stimulated human umbilical vein endothelial cells in a dose-time-dependent manner, inhibited cell's motility, and interfered with tubulogenesis. PSII also blocked microvessel outgrowth in a rat aortic ring assay and compromised angiogenesis in a mouse model of ovarian carcinoma using either SKOV3 or HOC-7 cell lines. VEGF levels in PSII-treated EC and tumor cells were reduced. In EC, PSII blocked the activation of VEGFR2 in dose-dependent manner leading to the reduction of VEGF-induced phosphorylation on several intracellular pro-angiogenic kinase, including the extracellular signal-related kinase, Src family kinase, focal adhesion kinase, and AKT kinase.

CONCLUSIONS

The results provided the first insight into the anti-angiogenesis properties of Saponin family in solid tumors and suggested a promising therapeutic potential of PSII in the ovarian cancer treatment.

Integrin-linked kinase regulates melanoma angiogenesis by activating NF-κB/interleukin-6 signaling pathway

Integrin-linked kinase (ILK) is a highly conserved serine-threonine protein kinase involved in cell-extracellular matrix interactions, cytoskeletal organization and cell signaling. Overexpression of ILK in epithelial cells leads to anchorage-independent growth with increased cell cycle progression. Previously, we have shown that ILK upregulation strongly correlates with melanoma progression, invasion and inversely correlates with 5-year survival of melanoma patients. However, the molecular mechanism by which ILK enhances melanoma progression is currently unknown. In the present study, we found that proangiogenic molecule interleukin-6 (IL-6) is the downstream target of ILK in melanoma cells. ILK overexpression increased IL-6, whereas silencing of ILK suppressed IL-6 expression at both messenger RNA and protein levels. ILK also altered the activity and subcellular localization of nuclear factor-kappaB (NF-κB) subunit p65. We further found that ILK enhanced the IL-6 gene transcription by promoting the binding of NF-κB p65 to IL-6 promoter. Moreover, ILK overexpression in melanoma cells enhanced the tube-forming ability of endothelial cells in vitro and microvessel formation in vivo. ILK-induced tube and blood vessel formation of endothelial cells was significantly reduced upon IL-6 inhibition in ILK-overexpressing melanoma cells. To delineate the mechanism by which ILK-induced IL-6 production can enhance angiogenesis, further analysis of the downstream targets of IL-6 signaling showed an increased activity of the signal transducer and activator of transcription 3 (STAT3) in ILK-overexpressing cells. As STAT3 binds to vascular endothelial growth factor (VEGF) promoter, we found that VEGF levels were elevated in ILK-overexpressing cells and declined upon transfection of IL-6 small interfering RNA, suggesting that ILK may regulate VEGF expression through IL-6 pathway by activating STAT3.

C5a promotes migration, proliferation, and vessel formation in endothelial cells

Objectives

The goal of this paper is to investigate the effects of activated complement C5a on vascular endothelium during vessel formation.

Methods

A human microvascular endothelial cell line (HMEC-1) derived from post-capillary venules in skin was used to measure DNA synthesis, proliferation and cell-cycle progression. In vitro ring-shaped formation by the cells was assessed by using type I collagen gel matrix and a cell-migration assay using the Chemotaxicell chamber. A Matrigel plug assay was performed to confirm the effect of C5a in vivo.

Results

C5a progressed the cell cycle of HMEC-1 into G2/M phases, and induced DNA synthesis and proliferation in a dose-dependent manner. C5a efficiently induced migration and ring-shaped structure formation both in vitro and in vivo. Furthermore, a C5a receptor antagonist (W-54011) suppressed all HMEC-1 activities including proliferation and migration.

Conclusions

Proliferation, migration, and ring-shaped formation by HMEC-1 cells was induced by C5a. The actions were efficiently inhibited by a specific antagonist against C5a. Our results implicated C5a in vessel formation and as a potent target for management of inflammatory diseases.

C5a promotes migration, proliferation, and vessel formation in endothelial cells

OBJECTIVES

The goal of this paper is to investigate the effects of activated complement C5a on vascular endothelium during vessel formation.

METHODS

A human microvascular endothelial cell line (HMEC-1) derived from post-capillary venules in skin was used to measure DNA synthesis, proliferation and cell-cycle progression. In vitro ring-shaped formation by the cells was assessed by using type I collagen gel matrix and a cell-migration assay using the Chemotaxicell chamber. A Matrigel plug assay was performed to confirm the effect of C5a in vivo.

RESULTS

C5a progressed the cell cycle of HMEC-1 into G2/M phases, and induced DNA synthesis and proliferation in a dose-dependent manner. C5a efficiently induced migration and ring-shaped structure formation both in vitro and in vivo. Furthermore, a C5a receptor antagonist (W-54011) suppressed all HMEC-1 activities including proliferation and migration.

CONCLUSIONS

Proliferation, migration, and ring-shaped formation by HMEC-1 cells was induced by C5a. The actions were efficiently inhibited by a specific antagonist against C5a. Our results implicated C5a in vessel formation and as a potent target for management of inflammatory diseases.

QLT0267, a small molecule inhibitor targeting integrin-linked kinase (ILK), and docetaxel can combine to produce synergistic interactions linked to enhanced cytotoxicity, reductions in P-AKT levels, altered F-actin architecture and improved treatment outcomes in an orthotopic breast cancer model

Introduction

Substantial preclinical evidence has indicated that inhibition of integrin linked-kinase (ILK) correlates with cytotoxic/cytostatic cellular effects, delayed tumor growth in animal models of cancer, and inhibition of angiogenesis. Widely anticipated to represent a very promising therapeutic target in several cancer indications, it is increasingly evident that optimal therapeutic benefits obtained using ILK targeting strategies will only be achieved in combination settings. The purpose of this study was to investigate the therapeutic potential of the ILK small molecule inhibitor, QLT0267 (267), alone or in combination with chemotherapies commonly used to treat breast cancer patients.

Methods

A single end-point metabolic assay was used as an initial screen for 267 interactions with selected chemotherapeutic agents. These in vitro assays were completed with seven breast cancer cell lines including several which over-expressed human epidermal growth factor receptor 2 (Her2). One agent, docetaxel (Dt), consistently produced synergistic interactions when combined with 267. Dt/267 interactions were further characterized by measuring therapeutic endpoints linked to phosphorylated protein kinase B (P-AKT) suppression, inhibition of vascular endothelial growth factor (VEGF) secretion and changes in cytoarchitecture. In vivo efficacy studies were completed in mice bearing orthotopic xenografts where tumor growth was assessed by bioluminescence and calliper methods.

Results

The combination of 267 and Dt resulted in increased cytotoxic activity, as determined using an assay of metabolic activity. Combinations of cisplatin, doxorubicin, vinorelbine, paclitaxel, and trastuzumab produced antagonistic interactions. Further endpoint analysis in cell lines with low Her2 levels revealed that the 267/Dt combinations resulted in: a three-fold decrease in concentration (dose) of 267 required to achieve 50% inhibition of P-AKT; and a dramatic disruption of normal filamentous-actin cellular architecture. In contrast to Her2-positive cell lines, three-fold higher concentrations of 267 were required to achieve 50% inhibition of P-AKT when the drug was used in combination with Dt. In vivo studies focusing on low Her2-expressing breast cancer cells (LCC6) implanted orthotopically demonstrated that treatment with 267/Dt engendered improved therapeutic effects when compared with mice treated with either agent alone.

Conclusions

The findings indicate that the 267/Dt drug combination confers increased (synergistic) therapeutic efficacy towards human breast cancer cells that express low levels of Her2.

Immobilization of growth factors on collagen scaffolds mediated by polyanionic collagen mimetic peptides and its effect on endothelial cell morphogenesis

Angiogenesis, a morphogenic event endothelial cells (ECs) undergo in response to 3-D environmental triggers, is critical to the survival and ultimate functional capacity of engineered tissue constructs. Here we present a new collagen mimetic peptide (CMP) architecture consisting of multiple anionic charges at the peptide's N-terminus designed to attract growth factors by charge-charge interactions and bind to collagen by CMP-collagen interaction. The anionic CMPs exhibited specific binding affinity to type I collagen substrates while attracting vascular endothelial growth factors (VEGFs), which led to enhanced morphological features of ECs, indicative of tubulogenesis. The results show that these new CMPs could be used to direct proliferation and differentiation of cells in collagen scaffolds by localization and sustained delivery of growth factors and other morphogens.

Establishment of a novel corneal endothelial cell line from domestic rabbit, Oryctolagus curiculus

To develop a rabbit corneal endothelial (RCE) cell line, in vitro culture of RCE cells was initiated from Oryctolagus curiculus corneas and a novel RCE cell line was established in this study. To initiate the primary culture of RCE cells, corneas from rabbit eyes were sliced and attached into glutin-coated wells with endothelial cell surface down. After being cultured at a time-gradient interval from 48 to 6 h, the corneal slices were detached and reattached into new wells, respectively. Cells in the wells containing only a pure population of RCE cells were collected and cultured in 20% FBS-DMEM/F12 medium containing chondroitin sulfate, ocular extract, epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), carboxymethyl-chitosan, N-acetylglucosamine hydrochloride, glucosamine hydrochloride, culture medium of rabbit corneal stromal cells and oxidation-degradation products of chondroitin sulfate at 37 degrees C, 5% CO(2). The cultured RCE cells, in quadrangle and polygonal shapes, proliferated to confluence 3 weeks later. During the subsequent subculture, the shape of RCE cells changed gradually from polygonal to more fibroblastic. A novel RCE cell line, growing at a steady rate, with a population doubling time of 53.8 h, has been established and subcultured to passage 67. Chromosome analysis showed that the RCE cells exhibited chromosomal aneuploidy with the modal chromosome number of 44. The results of immuno-cytochemical staining with neuron specific enolase (NSE) confirmed that the RCE cells were in neuroectodermal origin. Combined with the results of vascular endothelial growth factor (VEGF) treatment and endothelial cell morphology recovery, it can be concluded that the cell line established here is an RCE cell line. This RCE cell line may serve as a useful tool in theoretical researches of mammalian corneal endothelial cells, and may also have potential application in artificial corneal endothelium development.

Integrin-linked kinase is an essential mediator for T-cadherin-dependent signaling via Akt and GSK3beta in endothelial cells

Glycosylphosphatidylinositol-anchored T-cadherin (T-cad) influences several parameters of angiogenesis including endothelial cell (EC) differentiation, migration, proliferation, and survival. This presupposes signal transduction networking via mediatory regulators and molecular adaptors since T-cad lacks transmembrane and cytosolic domains. Here, using pharmacological inhibition of PI3K, adenoviral-mediated T-cad-overexpression, siRNA-mediated T-cad-depletion, and agonistic antibody-mediated ligation, we demonstrate signaling by T-cad through PI3K-Akt-GSK3beta pathways in EC. T-cad-overexpressing EC exhibited increased levels and nuclear accumulation of active beta-catenin, which was transcriptionally active as shown by increased Lef/Tcf reporter activity and cyclin D1 levels. Cotransduction of EC with constitutively active GSK3beta (S9A-GSK3beta) abrogated the stimulatory effects of T-cad on active beta-catenin accumulation, proliferation, and survival. Integrin-linked kinase (ILK), a membrane proximal upstream regulator of Akt and GSK3beta, was considered a candidate signaling mediator for T-cad. T-cad was present in anti-ILK immunoprecipitates, and confocal microscopy revealed colocalization of T-cad and ILK within lamellipodia of migrating cells. ILK-siRNA abolished T-cad-dependent effects on (Ser-473)Akt/(Ser-9)GSK3beta phosphorylation, active beta-catenin accumulation, and survival. We conclude ILK is an essential mediator for T-cad signaling via Akt and GSK3beta in EC. This is the first demonstration that ILK can regulate inward signaling by GPI-anchored proteins. Furthermore, ILK-GSK3beta-dependent modulation of active beta-catenin levels by GPI-anchored T-cad represents a novel mechanism for controlling cellular beta-catenin activity.

Integrin-Linked Kinase: It's Role in the Vascular System

Integrin-linked kinase (ILK) is an intracellular molecule that binds to the cytoplasmic domain of β1 and β3-integrin. It has been previously demonstrated in various epithelial cell lines to mediate the 'outside-in' signals into the cells and to control the survival of these cells by controlling the phosphorylation of various downstream proteins, such as protein kinase B/Akt (PKB/Akt). We now present in this review the important role of ILK in the vascular system with particular emphasis on its role in endothelial cells (ECs). The results presented here demonstrate that ILK is essential for the proper function, structure and survival of ECs and finally, for the process of neovascularization.

Enhancement of pituitary adenoma cell invasion and adhesion is mediated by discoidin domain receptor-1

The discoidin domain receptor-1 (DDR1) tyrosine kinases are a family of cell surface receptors that bind to several types of collagen and facilitate cell adhesion that is known association with several cancers. However, no previous study has examined the expression and function of DDR1 in pituitary adenoma. Tissue microarray analysis of DDR1 expression levels in 52 pituitary adenoma tissues revealed that DDR1 expression was significantly related to hormonal background (Kruskal-Wallis test; P < 0.0001). To further elucidate the function of DDR1 in pituitary adenoma, we developed DDR1 over- and under-expressing cell lines using DDR1 clone transfection and short interfering ribonucleic acids (siRNA)-based DDR1 gene silencing, respectively, in a human pituitary adenoma cell line (HP-75). Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting confirmed that expression of both DDR1 isoforms (DDR1a and DDR1b) was elevated by clone transfection and diminished by siRNA. Matrigel invasion assays revealed that cell invasion was increased in HP-75 cells over-expressing DDR1 and decreased in cells under-expressing DDR1. Consistent with this, zymography revealed that the activation levels of matrix metalloproteinase (MMP)-2 and -9 were increased and decreased in cells over- and under-expressing DDR1, respectively. Examination of in vitro cell adhesion to collagen types I, II, III, and IV with respect to MMP-2 and -9 expression revealed that DDR1 regulated cell adhesion to collagen type I, which was responsible for accelerating secretion of MMP-2 and -9 in DDR1 over-expressing cells. Taken together, these results strongly suggest that DDR1 mediates cell invasion-related signaling between collagen type I and MMP-2 and -9 in pituitary adenoma cells.