Latent effects of fibronectin, alpha5beta1 integrin, alphaVbeta5 integrin and the cytoskeleton regulate pancreatic carcinoma cell IL-8 secretion

Inhibition of integrin alpha v/beta 5 mitigates the protective effect induced by irisin in hemorrhage

INTRODUCTION

Irisin plays an important role in regulating tissue stress, cardiac function, and inflammation. Integrin αvβ5 was recently identified as a receptor for irisin to elicit its physiologic function. It remains unknown whether integrin αvβ5 is required for irisin's function in modulating the physiologic response to hemorrhage. The objective of this study is to examine if integrin αvβ5 contributes to the effects of irisin during the hemorrhagic response.

METHODS

Hemorrhage was induced in mice by achieving a mean arterial blood pressure of 35-45 mmHg for one hour, followed by two hours of resuscitation. Irisin (0.5  μg/kg) was administrated to assess its pharmacologic effects in hemorrhage. Cilengitide, a cyclic Arg-Gly-Asp peptide (cRGDyK) which is an inhibitor of integrin αvβ5, or control RGDS (1 mg/kg) was administered with irisin. In another cohort of mice, the irisin-induced protective effect was examined after knocking down integrin β5 with nanoparticle delivery of integrin β5 sgRNA using CRSIPR/Cas-9 gene editing. Cardiac function and hemodynamics were measured using echocardiography and femoral artery catheterization, respectively. Systemic cytokine releases were measured using Enzyme-linked immunosorbent assay (ELISA). Histological analyses were used to determine tissue damage in myocardium, skeletal muscles, and lung tissues. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was carried out to assess apoptosis in tissues.

RESULTS

Hemorrhage induced reduction of integrin αvβ5 in skeletal muscles and repressed recovery of cardiac performance and hemodynamics. Irisin treatment led to significantly improved cardiac function, which was abrogated by treatment with Cilengitide or knockdown of integrin β5. Furthermore, irisin resulted in a marked suppression of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1), muscle edema, and inflammatory cells infiltration in myocardium and skeletal muscles, which was attenuated by Cilengitide or knockdown of integrin β5. Irisin-induced reduction of apoptosis in the myocardium, skeletal muscles, and lung, which were attenuated by either the inhibition of integrin αvβ5, or knockdown of integrin β5.

CONCLUSION

Integrin αvβ5 plays an important role for irisin in modulating the protective effect during hemorrhage.

Mechanically stressed cancer microenvironment: Role in pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies in the world due to its insensitivity to current therapies and its propensity to metastases from the primary tumor mass. This is largely attributed to its complex microenvironment composed of unique stromal cell populations and extracellular matrix (ECM). The recruitment and activation of these cell populations cause an increase in deposition of ECM components, which highly influences the behavior of malignant cells through disrupted forms of signaling. As PDAC progresses from premalignant lesion to invasive carcinoma, this dynamic landscape shields the mass from immune defenses and cytotoxic intervention. This microenvironment influences an invasive cell phenotype through altered forms of mechanical signaling, capable of enacting biochemical changes within cells through activated mechanotransduction pathways. The effects of altered mechanical cues on malignant cell mechanotransduction have long remained enigmatic, particularly in PDAC, whose microenvironment significantly changes over time. A more complete and thorough understanding of PDAC's physical surroundings (microenvironment), mechanosensing proteins, and mechanical properties may help in identifying novel mechanisms that influence disease progression, and thus, provide new potential therapeutic targets.

Hydroxyapatite mineral enhances malignant potential in a tissue-engineered model of ductal carcinoma in situ (DCIS)

While ductal carcinoma in situ (DCIS) is known as a precursor lesion to most invasive breast carcinomas, the mechanisms underlying this transition remain enigmatic. DCIS is typically diagnosed by the mammographic detection of microcalcifications (MC). MCs consisting of non-stoichiometric hydroxyapatite (HA) mineral are frequently associated with malignant disease, yet it is unclear whether HA can actively promote malignancy. To investigate this outstanding question, we compared phenotypic outcomes of breast cancer cells cultured in control or HA-containing poly(lactide-co-glycolide) (PLG) scaffolds. Exposure to HA mineral in scaffolds increased the expression of pro-tumorigenic interleukin-8 (IL-8) among transformed but not benign cells. Notably, MCF10DCIS.com cells cultured in HA scaffolds adopted morphological changes associated with increased invasiveness and exhibited increased motility that were dependent on IL-8 signaling. Moreover, MCF10DCIS.com xenografts in HA scaffolds displayed evidence of enhanced malignant progression relative to xenografts in control scaffolds. These experimental findings were supported by a pathological analysis of clinical DCIS specimens, which correlated the presence of MCs with increased IL-8 staining and ductal proliferation. Collectively, our work suggests that HA mineral may stimulate malignancy in preinvasive DCIS cells and validate PLG scaffolds as useful tools to study cell-mineral interactions.

A 3D bioinspired highly porous polymeric scaffolding system for in vitro simulation of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma is an aggressive disease with an extremely low survival rate. This is due to the (i) poor prognosis and (ii) high resistance of the disease to current treatment options. The latter is partly due to the very complex and dense tissue/tumour microenvironment of pancreatic cancer, which contributes to the disease's progression and the inhibition of apoptotic pathways. Over the last years, advances in tissue engineering and the development of three-dimensional (3D) culture systems have shed more light into cancer research by enabling a more realistic recapitulation of the niches and structure of the tumour microenvironment. Herein, for the first time, 3D porous polyurethane scaffolds were fabricated and coated with fibronectin to mimic features of the structure and extracellular matrix present in the pancreatic cancer tumour microenvironment. The developed 3D scaffold could support the proliferation of the pancreatic tumour cells, which was enhanced with the presence of fibronectin, for a month, which is a significantly prolonged in vitro culturing duration. Furthermore, in situ imaging of cellular and biomarker distribution showed the formation of dense cellular masses, the production of collagen-I by the cells and the formation of environmental stress gradients (e.g. HIF-1α) with similar heterogeneity trends to the ones reported in in vivo studies. The results obtained in this study suggest that this bioinspired porous polyurethane based scaffold has great potential for in vitro high throughput studies of pancreatic cancer including drug and treatment screening.

Extracellular Influences: Molecular Subclasses and the Microenvironment in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent form of pancreatic cancer and carries the worst prognosis of all common cancers. Five-year survival rates have not surpassed 6% for some decades and this lack of improvement in outcome urges a better understanding of the PDAC-specific features which contribute to this poor result. One of the most defining features of PDAC known to contribute to its progression is the abundance of non-tumor cells and material collectively known as the stroma. It is now well recognized that the different non-cancer cell types, signalling molecules, and mechanical properties within a tumor can have both tumor-promoting as well as –inhibitory effects. However, the net effect of this intratumour heterogeneity is not well understood. Heterogeneity in the stromal makeup between patients is even less well established. Such intertumour heterogeneity is likely to be affected by the relative contributions of individual stromal constituents, but how these contributions exactly relate to existing classifications that demarcate intertumour heterogeneity in PDAC is not fully known. In this review, we give an overview of the available evidence by delineating the elements of the PDAC stroma and their contribution to tumour growth. We do so by interpreting the heterogeneity at the gene expression level in PDAC, and how stromal elements contribute to, or interconnect, with this.

Collagen I hydrogel microstructure and composition conjointly regulate vascular network formation

Neovascularization is a hallmark of physiological and pathological tissue remodeling that is regulated in part by the extracellular matrix (ECM). Collagen I hydrogels or Matrigel are frequently used to study vascular network formation; however, in isolation these materials do not typically mimic the integrated effects of ECM structure and composition that may influence endothelial cells in vivo. Here, we have utilized microfabricated 3D culture models to control collagen I microstructure in the presence and absence of Matrigel and tested the effect of these variations on vascular network formation by human cerebral microvascular endothelial cells (hCMECs). Varied collagen microarchitecture was achieved by adjusting the gelation temperature and subsequently confirmed by structural analysis. Casting at colder temperature increased collagen fiber thickness and length, and inclusion of Matrigel further pronounced these differences. Interestingly, the presence of Matrigel affected vascular network formation by modulating hCMEC growth, whereas altered collagen fiber structure impacted the morphology and maturity of the developed vascular network. These differences were related to substrate-dependent changes in interleukin-8 (IL-8) secretion and were functionally relevant as vascular networks preformed in more fibrillar, Matrigel-containing hydrogels promoted angiogenic sprouting. Our studies indicate that collagen hydrogel microstructure and composition conjointly regulate vascular network formation with implications for translational and basic science approaches.

STATEMENT OF SIGNIFICANCE

Neovascularization is a hallmark of both tissue homeostasis and disease and is in part regulated by cell remodeling that occurs in the extracellular matrix (ECM). The use of bio-mimetic hydrogel cell culture systems has been used to study the effects of the ECM on cell behavior. Here, we employ a hydrogel system that enables control over both the structure and composition of the ECM and subsequently investigated the effects that these have on blood vessel dynamics. Finally, we linked these differences to changes in protein secretion and the implications that this may play in scientific translation.

Interaction of tumour cells with their microenvironment: ion channels and cell adhesion molecules. A focus on pancreatic cancer

Cancer must be viewed as a 'tissue', constituted of both transformed cells and a heterogeneous microenvironment, the 'tumour microenvironment' (TME). The TME undergoes a complex remodelling during the course of multistep tumourigenesis, hence strongly contributing to tumour progression. Ion channels and transporters (ICTs), being expressed on both tumour cells and in the different cellular components of the TME, are in a strategic position to sense and mediate signals arising from the TME. Often, this transmission is mediated by integrin adhesion receptors, which are the main cellular receptors capable of mediating cell-to-cell and cell-to-matrix bidirectional signalling. Integrins can often operate in conjunction with ICT because they can behave as functional partners of ICT proteins. The role of integrin receptors in the crosstalk between tumour cells and the TME is particularly relevant in the context of pancreatic cancer (PC), characterized by an overwhelming TME which actively contributes to therapy resistance. We discuss the possibility that this occurs through integrins and ICTs, which could be exploited as targets to overcome chemoresistance in PC.

Promotion of tumor cell migration by extracellular matrix proteins in human pancreatic cancer

OBJECTIVES

The pathogenesis of pancreatic carcinoma is driven by the tumor cells ability to migrate causing invasion and metastases. The correlation between the aberrant expression of basement membrane proteins and the process of tumor invasion and metastasis has not been fully determined.

METHODS

In the present study, the influence of laminin, fibronectin, and collagen type IV on migratory activity of 5 different cell lines has been investigated at the level of a single tumor cell using 3-dimensional time-lapse microscopy.

RESULTS

All investigated cell lines have shown a high baseline migration that varied between 6.2 +/- 3.6 and 20.6 +/- 6.8 microm/h. The addition of laminin, fibronectin, and collagen type IV to collagen type I matrix has significantly increased tumor cell migration. Tumor cell migration was strongly inhibited after treating the tumor cells with anti-beta1 monoclonal antibodies. An abundant and continuous expression of laminin, fibronectin, and collagen type IV was found on the basement membrane of perineurium, which sharply promoted tumor cell invasion.

CONCLUSIONS

The continuous presentation of the basement membrane proteins by perineurium contributes to the affinity of pancreatic cancer cells for the perineural tumor invasion. Blockade of integrins could represent a possible approach to control the basement membrane-guided tumor spread.

Parylene peel-off arrays to probe the role of cell-cell interactions in tumour angiogenesis

Microenvironmental conditions impact tumour angiogenesis, but the role of cell-cell interactions in modulating the angiogenic capability of tumour cells is not well understood. We have microfabricated a peel-off cell-culture array (PeelArray) chip to spatiotemporally control interactions between tumour cells in a large array format and to analyse angiogenic factor secretion in response to these conditions. The PeelArray chip consists of a polyethylene glycol (PEG) treated glass coverslip coated with a parylene-C template that can be easily peeled off to selectively micropattern biomolecules and cells. We have designed the PeelArray chip to reproducibly deposit large uniform arrays of isolated single cells or isolated cell clusters on fibronectin features of defined surface areas. We have utilised this microfabricated culture system to study the secretion of angiogenic factors by tumour cells, in the presence or absence of cell-cell contact as controlled by micropatterning. Our results indicate that cell-cell interactions play a synergistic role in regulating the expression of angiogenic factors (i.e., vascular endothelial growth factor [VEGF] and interleukin-8 [IL-8]) in various cancer cell lines, independent of other more complex microenvironmental cues (e.g. hypoxia). Our PeelArray chip is a simple and adaptable micropatterning method that enables quantitative profiling of protein secretions and hence, a better understanding of the mechanisms by which cell-cell interactions regulate tumour cell behaviour and angiogenesis.

Cancer cell angiogenic capability is regulated by 3D culture and integrin engagement

Three-dimensional culture alters cancer cell signaling; however, the underlying mechanisms and importance of these changes on tumor vascularization remain unclear. A hydrogel system was used to examine the role of the transition from 2D to 3D culture, with and without integrin engagement, on cancer cell angiogenic capability. Three-dimensional culture recreated tumor microenvironmental cues and led to enhanced interleukin 8 (IL-8) secretion that depended on integrin engagement with adhesion peptides coupled to the polymer. In contrast, vascular endothelial growth factor (VEGF) secretion was unaffected by 3D culture with or without substrate adhesion. IL-8 diffused greater distances and was present in higher concentrations in the systemic circulation, relative to VEGF. Implantation of a polymeric IL-8 delivery system into GFP bone marrow-transplanted mice revealed that localized IL-8 up-regulation was critical to both the local and systemic control of tumor vascularization in vivo. In summary, 3D integrin engagement within tumor microenvironments regulates cancer cell angiogenic signaling, and controlled local and systemic blockade of both IL-8 and VEGF signaling may improve antiangiogenic therapies.

Inverted microcontact printing on polystyrene-block-poly(tert-butyl acrylate) films: a versatile approach to fabricate structured biointerfaces across the length scales

The combination of the recently introduced soft lithographic technique of inverted microcontact printing (i-muCP) and spin-coated films of polystyrene- block-poly( tert-butyl acrylate) (PS 690- b-P tBA 1210) as a reactive platform is shown to yield a versatile approach for the facile fabrication of topographically structured and chemically patterned biointerfaces with characteristic spacings and distances that cross many orders of magnitude. The shortcomings of conventional muCP in printing of small features with large spacings, due to the collapse of small or high aspect ratio stamp structures, are circumvented in i-muCP by printing reactants using a featureless elastomeric stamp onto a topographically structured reactive polymer film. Prior to molecular transfer, the substrate-supported PS 690- b-P tBA 1210 films were structured by imprint lithography resulting in lateral and vertical feature sizes between >50 microm-150 nm and >1.0 microm-18 nm, respectively. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and water contact angle measurements provided evidence for the absence of surface chemical transformations during the imprinting step. Following the previously established hydrolysis and activation protocol with trifluoroacetic acid and N-hydroxysuccinimide, amino end-functionalized poly(ethylene glycol) (PEG-NH 2), as well as bovine serum albumin and fibronectin as model proteins, were successfully transferred by i-muCP and coupled covalently. As shown, i-muCP yields increased PEG coverages and thus improved performance in suppressing nonspecific adsorption of proteins by exploiting the high local concentrations in the micro- and nanocontacts during molecular transfer. The i-muCP strategy provides access to versatile biointerface platforms patterned across the length scales, as shown for guided cancer cell adhesion, which opens the pathway for systematic cell-surface interaction studies.

Integrin-mediated laminin-1 adhesion upregulates CXCR4 and IL-8 expression in pancreatic cancer cells

BACKGROUND

We have shown recently that alpha(2)beta(1) integrin-mediated type I collagen adhesion promotes a more malignant phenotype in pancreatic cancer cell lines than other extracellular matrix (ECM) proteins. MiaPaCa-2 cells, by contrast, do not express collagen-binding integrins, but are metastatic in our orthotopic mouse model and migrate maximally on laminin-1 (Ln-1). It has also been shown that CXCR4 and IL-8 expression correlates directly with metastasis in pancreatic cancer in vivo. We therefore examined the potential of the ECM to regulate CXCR4 and IL-8 expression in pancreatic cancer cells.

METHODS

We cultured 8 pancreatic cancer cell lines on fibronectin (Fn), types I and IV collagen, Ln-1 and vitronectin (Vn), and examined cell lysates for CXCR4 by immunoblotting and media for IL-8 by ELISA. We also conducted cell migration assays with stromal-derived factor-1 (SDF-1) as the chemoattractant to examine integrin-binding specificity and CXCR4 function.

RESULTS

All cell lines expressed CXCR4 protein. MiaPaCa-2 cell growth on Ln-1 increased significantly CXCR4 and IL-8 expression relative to other ECM proteins. Migration inhibition studies showed that both the alpha(6)beta(1) and alpha(3)beta(1) integrins mediate MiaPaCa-2 migration on Ln-1. Growth studies showed further that CXCR4 expression on Ln-1 was mediated by the alpha(6)beta(1) integrin whereas IL-8 expression was mediated by both the alpha(6)beta(1) and alpha(3)beta(1) integrins. The expression of functional CXCR4 was also shown in migration assays, where SDF-1 significantly increased pancreatic cancer cell chemotaxis on Ln-1.

CONCLUSIONS

These data indicate that integrin-mediated Ln-1 adhesion upregulates CXCR4 and IL-8 expression and may play a mechanistic role in pancreatic cancer metastases.

Tumor-stroma interactions in pancreatic ductal adenocarcinoma

The host stromal response to an invasive epithelial carcinoma is frequently called a desmoplastic reaction (DR) and is a universal feature of pancreatic ductal adenocarcinoma (PDA). This DR is characterized by a complex interplay between the normal host epithelial cells, invading tumor cells, stromal fibroblasts, inflammatory cells, proliferating endothelial cells, an altered extracellular matrix, and growth factors activating oncogenic signaling pathways by autocrine and paracrine mechanisms. Hence, the tumor microenvironment is a dynamic process promoting tumor growth and invasion through mechanisms likely to include anoikis resistance, genomic instability, and drug resistance. Cell coculture models, murine models (xenograft and genetic), and gene expression profiling studies on human PDA biopsies have identified several key molecules, such as collagen type I, fibronectin, laminin, matrix metalloproteinases (MMP) and their inhibitors (tissue inhibitors of MMP), growth factors (transforming growth factor beta, platelet-derived growth factor, connective tissue growth factor, and hepatocyte growth factor), chemokines, and integrins as constituents of the DR. Despite these findings, it is unclear which molecular-cellular events initiate and drive desmoplasia in PDA. Accumulating evidence indicates that pancreatic stellate cells when activated switch to a myofibroblast phenotype that produces components of the extracellular matrix, MMPs, and tissue inhibitors of MMPs by activating the mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2) pathway. Based on current evidence, several therapeutic strategies are been evaluated on identified potential therapeutic targets. This review summarizes our current understanding of the mechanisms that potentially drive the DR in PDA and future possibilities for therapeutic targeting of this critical process.

Saxatilin inhibits TNF-α-induced proliferation by suppressing AP-1-dependent IL-8 expression in the ovarian cancer cell line MDAH 2774

Tumor necrosis factor-alpha (TNF-alpha)-induced proliferation of cancer cell line MDAH 2774 was significantly suppressed by treating the cells with saxatilin, a snake venom disintegrin. The suppressed proliferation was found to be associated with the level of interleukin-8 (IL-8) expression in the cells. TNF-alpha-induced IL-8 promoter activation that is inhibited by saxatilin treatment was dependent on activating protein-1 (AP-1) instead of nuclear factor-kappa B (NF-kappaB). Coexpression of dominant negative p38 (DN-p38) suggested that p38 is involved in the IL-8 promoter activity which is regulated by saxatilin or TNF-alpha. Experimental evidence clearly indicated that saxatilin inhibits TNF-alpha-induced proliferation of the ovarian cancer cells by suppressing IL-8 expression in AP-1-dependent manner.

Roles of integrins in pancreatic adenocarcinoma

Integrins, serving as transmembrane proteins, play major roles in cell-extracellular matrix adhesions, and they can introduce extracellular signals into the cells, alter cellular morphology and influence cell motility as well as contribute to tumor invasion and metastasis. One of the major causes of low resection rates and extremely poor survival rates is its extraordinary local tumor progression and early systemic dissemination. Being a kind of adhesion molecules associating cells with extracellular matrix, integrins play a variety of roles in the process of invasion and metastasis in pancreatic adenocarcinoma.

Anti-CD146 monoclonal antibody AA98 inhibits angiogenesis via suppression of nuclear factor-κB activation

Our previous study showed that an anti-CD146 monoclonal antibody (mAb), AA98, which was raised against the vascular endothelial cells stimulated by a conditioned medium from hepatocarcinoma SMMC 7721 cells (SMMC 7721-CM), inhibited cell migration, angiogenesis, and tumor growth. However, the underlying mechanism was not elucidated. The objective of this study was to understand the mechanism by which mAb AA98 inhibits the endothelial cell migration and angiogenesis that is induced by SMMC 7721-CM. Using confocal imaging and biochemical studies, we found that SMMC 7721-CM induced nuclear factor kappaB (NF-kappaB) activation through the upstream p38 mitogen-activated protein kinase pathway, leading to the up-regulation of matrix metalloproteinase 9 and intercellular adhesion molecule 1 expression. Interestingly, all these activities stimulated by SMMC 7721-CM could be effectively inhibited by mAb AA98 in a dose- and time-dependent manner. Our data showed that the engagement of mAb AA98 with membrane protein CD146 inhibited p38 mitogen-activated protein kinase phosphorylation, suppressed NF-kappaB activation, and down-regulated matrix metalloproteinase 9 and intercellular adhesion molecule 1 expression, suggesting that the suppression of NF-kappaB is a critical point for the inhibitory function of mAb AA98 on endothelial cell migration, angiogenesis, and tumor metastasis. These results will provide clues for a better understanding of the mechanisms underlying tumor angiogenesis as well as antiangiogenesis therapy.