Structural and mechanical functions of integrins

Targeted Nanoparticle-Based Diagnostic and Treatment Options for Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest cancers, presents significant challenges in diagnosis and treatment due to its aggressive, metastatic nature and lack of early detection methods. A key obstacle in PDAC treatment is the highly complex tumor environment characterized by dense stroma surrounding the tumor, which hinders effective drug delivery. Nanotechnology can offer innovative solutions to these challenges, particularly in creating novel drug delivery systems for existing anticancer drugs for PDAC, such as gemcitabine and paclitaxel. By using customization methods such as incorporating conjugated targeting ligands, tumor-penetrating peptides, and therapeutic nucleic acids, these nanoparticle-based systems enhance drug solubility, extend circulation time, improve tumor targeting, and control drug release, thereby minimizing side effects and toxicity in healthy tissues. Moreover, nanoparticles have also shown potential in precise diagnostic methods for PDAC. This literature review will delve into targeted mechanisms, pathways, and approaches in treating pancreatic cancer. Additional emphasis is placed on the study of nanoparticle-based delivery systems, with a brief mention of those in clinical trials. Overall, the overview illustrates the significant advances in nanomedicine, underscoring its role in transcending the constraints of conventional PDAC therapies and diagnostics.

Molecular Regulation and Oncogenic Functions of TSPAN8

Tetraspanins, a superfamily of small integral membrane proteins, are characterized by four transmembrane domains and conserved protein motifs that are configured into a unique molecular topology and structure in the plasma membrane. They act as key organizers of the plasma membrane, orchestrating the formation of specialized microdomains called "tetraspanin-enriched microdomains (TEMs)" or "tetraspanin nanodomains" that are essential for mediating diverse biological processes. TSPAN8 is one of the earliest identified tetraspanin members. It is known to interact with a wide range of molecular partners in different cellular contexts and regulate diverse molecular and cellular events at the plasma membrane, including cell adhesion, migration, invasion, signal transduction, and exosome biogenesis. The functions of cell-surface TSPAN8 are governed by ER targeting, modifications at the Golgi apparatus and dynamic trafficking. Intriguingly, limited evidence shows that TSPAN8 can translocate to the nucleus to act as a transcriptional regulator. The transcription of TSPAN8 is tightly regulated and restricted to defined cell lineages, where it can serve as a molecular marker of stem/progenitor cells in certain normal tissues as well as tumors. Importantly, the oncogenic roles of TSPAN8 in tumor development and cancer metastasis have gained prominence in recent decades. Here, we comprehensively review the current knowledge on the molecular characteristics and regulatory mechanisms defining TSPAN8 functions, and discuss the potential and significance of TSPAN8 as a biomarker and therapeutic target across various epithelial cancers.

RGD peptide in cancer targeting: Benefits, challenges, solutions, and possible integrin-RGD interactions

RGD peptide can be found in cell adhesion and signaling proteins, such as fibronectin, vitronectin, and fibrinogen. RGD peptides' principal function is to facilitate cell adhesion by interacting with integrin receptors on the cell surface. They have been intensively researched for use in biotechnology and medicine, including incorporation into biomaterials, conjugation to medicinal molecules or nanoparticles, and labeling with imaging agents. RGD peptides can be utilized to specifically target cancer cells and the tumor vasculature by engaging with these integrins, improving drug delivery efficiency and minimizing adverse effects on healthy tissues. RGD-functionalized drug carriers are a viable option for cancer therapy as this focused approach has demonstrated promise in the future. Writing a review on the RGD peptide can significantly influence how drugs are developed in the future by improving our understanding of the peptide, finding knowledge gaps, fostering innovation, and making drug design easier.

Differential modulation of cellular phenotype and drug sensitivity by extracellular matrix proteins in primary and metastatic pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is reported to be the third highest cause of cancer-related deaths in the United States. PDAC is known for its high proportion of stroma, which accounts for 90% of the tumor mass. The stroma is made up of extracellular matrix (ECM) and nonmalignant cells such as inflammatory cells, cancer-associated fibroblasts, and lymphatic and blood vessels. Here, we decoupled the effects of the ECM on PDAC cell lines by culturing cells on surfaces coated with different ECM proteins. Our data show that the primary tumor-derived cell lines have different morphology depending on the ECM proteins on which they are cultured, while metastatic lesion-derived PDAC lines' morphology does not change with respect to the different ECM proteins. Similarly, ECM proteins modulate the proliferation rate and the gemcitabine sensitivity of the primary tumor PDAC cell lines, but not the metastatic PDAC lines. Lastly, transcriptomics analysis of the primary tumor PDAC cells cultured on different ECM proteins reveals the regulation of various pathways, such as cell cycle, cell-adhesion molecules, and focal adhesion, including the regulation of several integrin genes that are essential for ECM recognition.

Biomimetic Fibers Based on Equidistant Micropillar Arrays Determines Chondrocyte Fate via Mechanoadaptability

It is recognized that the changes in the physical properties of extracellular matrix (ECM) result in fine-tuned cell responses including cell morphology, proliferation and differentiation. In this study, a novel patterned equidistant micropillar substrate based on polydimethylsiloxane (PDMS) is designed to mimic the collagen fiber-like network of the cartilage matrix. By changing the component of the curing agent to an oligomeric base, micropillar substrates with the same topology but different stiffnesses are obtained and it is found that chondrocytes seeded onto the soft micropillar substrate maintain their phenotype by gathering type II collagen and aggrecan more effectively than those seeded onto the stiff micropillar substrate. Moreover, chondrocytes sense and respond to micropillar substrates with different stiffnesses by altering the ECM-cytoskeleton-focal adhesion axis. Further, it is found that the soft substrate-preserved chondrocyte phenotype is dependent on the activation of Wnt/β-catenin signaling. Finally, it is indicated that the changes in osteoid-like region formation and cartilage phenotype loss in the stiffened sclerotic area of osteoarthritis cartilage to validate the changes triggered by micropillar substrates with different stiffnesses. This study provides the cell behavior changes that are more similar to those of real chondrocytes at tissue level during the transition from a normal state to a state of osteoarthritis.

The β6 Integrin Negatively Regulates TLR7-Mediated Epithelial Immunity via Autophagy During Influenza A Virus Infection

Integrins are essential surface receptors that sense extracellular changes to initiate various intracellular signaling cascades. The rapid activation of the epithelial-intrinsic β6 integrin during influenza A virus (IAV) infection has been linked to innate immune impairments. Yet, how β6 regulates epithelial immunity remains undefined. Here, we identify the role of β6 in mediating the Toll-like receptor 7 (TLR7) through the regulation of intracellular trafficking. We demonstrate that deletion of the β6 integrin in lung epithelial cells significantly enhances the TLR7-mediated activation of the type I interferon (IFN) response during homeostasis and respiratory infection. IAV-induced β6 facilitates TLR7 trafficking to lysosome-associated membrane protein (LAMP2a) components, leading to a reduction in endosomal compartments and associated TLR7 signaling. Our findings reveal an unappreciated role of β6-induced autophagy in influencing epithelial immune responses during influenza virus infection.

Molecular basis of conformational changes and mechanics of integrins

Integrin, as a mechanotransducer, establishes the mechanical reciprocity between the extracellular matrix (ECM) and cells at integrin-mediated adhesion sites. This study used steered molecular dynamics (SMD) simulations to investigate the mechanical responses of integrin α_vβ₃ with and without 10th type III fibronectin (FnIII₁₀) binding for tensile, bending and torsional loading conditions. The ligand-binding integrin confirmed the integrin activation during equilibration and altered the integrin dynamics by changing the interface interaction between β-tail, hybrid and epidermal growth factor domains during initial tensile loading. The tensile deformation in integrin molecules indicated that fibronectin ligand binding modulates its mechanical responses in the folded and unfolded conformation states. The bending deformation responses of extended integrin models reveal the change in behaviour of integrin molecules in the presence of Mn²⁺ ion and ligand based on the application of force in the folding and unfolding directions of integrin. Furthermore, these SMD simulation results were used to predict the mechanical properties of integrin underlying the mechanism of integrin-based adhesion. The evaluation of integrin mechanics provides new insights into understanding the mechanotransmission (force transmission) between cells and ECM and contributes to developing an accurate model for integrin-mediated adhesion. This article is part of a discussion meeting issue 'Supercomputing simulations of advanced materials'.

New opportunities for RGD-engineered metal nanoparticles in cancer

The advent of nanotechnology has opened new possibilities for bioimaging. Metal nanoparticles (such as gold, silver, iron, copper, etc.) hold tremendous potential and offer enormous opportunities for imaging and diagnostics due to their broad optical characteristics, ease of manufacturing technique, and simple surface modification. The arginine-glycine-aspartate (RGD) peptide is a three-amino acid sequence that seems to have a considerably greater ability to adhere to integrin adhesion molecules that exclusively express on tumour cells. RGD peptides act as the efficient tailoring ligand with a variety of benefits including non-toxicity, greater precision, rapid clearance, etc. This review focuses on the possibility of non-invasive cancer imaging using metal nanoparticles with RGD assistance.

Tumor cell integrin β4 and tumor stroma E-/P-selectin cooperatively regulate tumor growth in vivo

BACKGROUND

The immunological composition of the tumor microenvironment has a decisive influence on the biological course of cancer and is therefore of profound clinical relevance. In this study, we analyzed the cooperative effects of integrin β4 (ITGB4) on tumor cells and E-/P-selectin on endothelial cells within the tumor stroma for regulating tumor growth by shaping the local and systemic immune environment.

METHODS

We used several preclinical mouse models for different solid human cancer types (xenograft and syngeneic) to explore the role of ITGB4 (shRNA-mediated knockdown in tumor cells) and E-/P-selectins (knockout in mice) for tumor growth; effects on apoptosis, proliferation and intratumoral signaling pathways were determined by histological and biochemical methods and 3D in vitro experiments; changes in the intratumoral and systemic immune cell composition were determined by flow cytometry and immunohistochemistry; chemokine levels and their attracting potential were measured by ELISA and 3D invasion assays.

RESULTS

We observed a very robust synergism between ITGB4 and E-/P-selectin for the regulation of tumor growth, accompanied by an increased recruitment of CD11b⁺ Gr-1^Hi cells with low granularity (i.e., myeloid-derived suppressor cells, MDSCs) specifically into ITGB4-depleted tumors. ITGB4-depleted tumors undergo apoptosis and actively attract MDSCs, well-known to promote tumor growth in several cancers, via increased secretion of different chemokines. MDSC trafficking into tumors crucially depends on E-/P-selectin expression. Analyses of clinical samples confirmed an inverse relationship between ITGB4 expression in tumors and number of tumor-infiltrating leukocytes.

CONCLUSIONS

These findings suggest a distinct vulnerability of ITGB4^Lo tumors for MDSC-directed immunotherapies.

Mechanisms of Foreign Body Giant Cell Formation in Response to Implantable Biomaterials

Long term function of implantable biomaterials are determined by their integration with the host's body. Immune reactions against these implants could impair the function and integration of the implants. Some biomaterial-based implants lead to macrophage fusion and the formation of multinucleated giant cells, also known as foreign body giant cells (FBGCs). FBGCs may compromise the biomaterial performance and may lead to implant rejection and adverse events in some cases. Despite their critical role in response to implants, there is a limited understanding of cellular and molecular mechanisms involved in forming FBGCs. Here, we focused on better understanding the steps and mechanisms triggering macrophage fusion and FBGCs formation, specifically in response to biomaterials. These steps included macrophage adhesion to the biomaterial surface, fusion competency, mechanosensing and mechanotransduction-mediated migration, and the final fusion. We also described some of the key biomarkers and biomolecules involved in these steps. Understanding these steps on a molecular level would lead to enhance biomaterials design and improve their function in the context of cell transplantation, tissue engineering, and drug delivery.

Pathophysiological roles of integrins in gliomas from the perspective of glioma stem cells

Glioblastoma is the most common primary intracranial tumor and is also one of the most malignant central nervous system tumors. Its characteristics, such as high malignancy, abundant tumor vasculature, drug resistance, and recurrence-prone nature, cause great suffering to glioma patients. Furthermore, glioma stem cells are the primordial cells of the glioma and play a central role in the development of glioma. Integrins—heterodimers composed of noncovalently bound a and ß subunits—are highly expressed in glioma stem cells and play an essential role in the self-renewal, differentiation, high drug resistance, and chemo-radiotherapy resistance of glioma stem cells through cell adhesion and signaling. However, there are various types of integrins, and their mechanisms of function on glioma stem cells are complex. Therefore, this article reviews the feasibility of treating gliomas by targeting integrins on glioma stem cells.

Integrin β1/Cell Surface GRP78 Complex Regulates TGFβ1 and Its Profibrotic Effects in Response to High Glucose

Diabetic kidney disease (DKD) is the leading cause of kidney failure worldwide. Characterized by overproduction and accumulation of extracellular matrix (ECM) proteins, glomerular sclerosis is its earliest manifestation. High glucose (HG) plays a central role by increasing matrix production by glomerular mesangial cells (MC). We previously showed that HG induces translocation of GRP78 from the endoplasmic reticulum to the cell surface (csGRP78), where it acts as a signaling molecule to promote intracellular profibrotic FAK/Akt activation. Here, we identify integrin β1 as a key transmembrane signaling partner for csGRP78. We show that it is required for csGRP78-regulated FAK/Akt activation in response to HG, as well as downstream production, secretion and activity of the well characterized profibrotic cytokine transforming growth factor β1 (TGFβ1). Intriguingly, integrin β1 also itself promotes csGRP78 translocation. Furthermore, integrin β1 effects on cytoskeletal organization are not required for its function in csGRP78 translocation and signaling. These data together support an important pathologic role for csGRP78/integrin β1 in mediating key profibrotic responses to HG in kidney cells. Inhibition of their interaction will be further evaluated as a therapeutic target to limit fibrosis progression in DKD.

The involvement of a chemokine receptor antagonist CTCE-9908 and kynurenine metabolites in cancer development

Cancer is the second leading cause of mortality worldwide. Skin cancer is the most common cancer in South Africa with nearly 20,000 reported cases every year and 700 deaths. If diagnosed early, the 5-year survival rate is about 90%, however, when diagnosed late, the 5-year survival rate decreases to about 20%. Melanoma is a type of skin cancer with an estimated 5-year survival rate of approximately 90%. Neuroblastoma is a paediatric cancer with a low survival rate. Sixty percent of patients with metastatic disease do not survive 5 years after diagnosis. Despite recent advances in targeted therapies, there is a crucial need to identify reliable prognostic biomarkers which will be able to contribute to the development of more precision-based chemotherapeutic strategies to prevent tumour migration and metastasis. The compound, CTCE-9908 inhibits the binding of CXC chemokine ligand 12 (CXCL12) to the CXC chemokine receptor 4 (CXCR4) receptor leading to reduced metastasis. Kynurenine metabolites are derived tryptophan, which is an essential amino acid. Kynurenine metabolites inhibit T-cell proliferation resulting in cell growth arrest. For this reason, chemokines receptors represent potential targets for the treatment of cancer growth and metastasis. In this review paper, the role of the CXCL12/CXCR4 signalling pathway in the development of cancer is highlighted together with the current available treatments involving the CTCE-9908 compound in combination with microtubule inhibitors like paclitaxel and docetaxel.

Caffeine Induces G0/G1 Cell Cycle Arrest and Inhibits Migration through Integrin αv, β3, and FAK/Akt/c-Myc Signaling Pathway

Lung cancer is recognized as a major cause of mortality worldwide owing to its metastatic activity. Given the lack of solid information regarding the possible effects of caffeine, one of the most consumed natural psychoactive substances, on molecular signaling pathways implicated in the aggressive behavior of lung cancer, our study aimed to evaluate the effect and mechanism of caffeine on metastasis-related mechanisms. The results revealed that caffeine treatment at concentrations of 0-500 µM caused no direct cytotoxic effects on NCI-H23 cells. Treatment of cells with caffeine showed good potential to inhibit cell proliferation at 48 h and induced significant cell cycle arrest at the G0/G1 phase. Concerning metastasis, caffeine was shown to reduce filopodia formation, inhibit migration and invasion capability, and reduce the ability of cancer cells to survive and grow in an anchorage-independent manner. Moreover, caffeine could attenuate the formation of 3D tumor spheroids in cancer stem cell (CSC)-enriched populations. With regard to mechanisms, we found that caffeine significantly altered the integrin pattern of the treated cells and caused the downregulation of metastasis-associated integrins, namely, integrins αv and β3. Subsequently, the downstream signals, including protein signaling and transcription factors, namely, phosphorylated focal adhesion kinase (p-FAK), phosphorylated protein kinase B (p-Akt), cell division cycle 42 (Cdc42), and c-Myc, were significantly decreased in caffeine-exposed cells. Taken together, our novel data on caffeine-inhibiting mechanism in relation to metastasis in lung cancer could provide insights into the impact of caffeine intake on human diseases and conditions.

The effect of endocrine disrupting chemicals on the vitronectin-receptor (integrin αvβ3)-mediated cell adhesion of human umbilical vein endothelial cells

Endocrine disrupting chemicals (EDCs) are associated with cancer development and progression due to their promotion of increased cell invasiveness and metastasis formation. However, the effects of EDCs on cell adhesion mediated through integrins have not been well studied to date. Their actions are implicated by binding sites for hormones on the vitronectin receptor (VTNR; or integrin α_vβ₃), which is involved in tumor angiogenesis and metastasis. VTNR-expressing human umbilical vein endothelial cells (HUVECs) were used to determine the effects of EDCs and endogenous hormones on cell adhesion to vitronectin-coated surfaces, and on VTNR activation. Cell adhesion was significantly increased for bisphenol A, triclocarban, and triclosan (10, 100 nM; p < 0.05), with similar trends for bisphenols AF and S (10, 100 nM; p > 0.05). No changes in cell adhesion were seen for 5α-dihydrotestosterone, 17β-estradiol, triiodothyronine, imatinib and paroxetine. These data indicate that EDC-mediated increases in HUVEC adhesion to vitronectin are not mediated through androgenic, estrogenic, or thyroid activities, nor through activation of VTNR. Although these effects of EDCs on HUVEC adhesion require further investigation of the underlying mechanism(s) of action to define their biological relevance, the low-dose effects and nonmonotonic responses revealed here define the need for further investigation of these EDCs.

Krüppel-like Factor 2 (KLF2) in Immune Cell Migration

Krüppel-like factor 2 (KLF2), a transcription factor of the krüppel-like family, is a key regulator of activation, differentiation, and migration processes in various cell types. In this review, we focus on the functional relevance of KLF2 in immune cell migration and homing. We summarize the key functions of KLF2 in the regulation of chemokine receptors and adhesion molecules and discuss the relevance of the KLF2-mediated control of immune cell migration in the context of immune responses, infections, and diseases.

2D biointerfaces to study stem cell-ligand interactions

Stem cells have great potential in the field of tissue engineering and regenerative medicine due to their inherent regenerative capabilities. However, an ongoing challenge within their clinical translation is to elicit or predict the desired stem cell behavior once transplanted. Stem cell behavior and function are regulated by their interaction with biophysical and biochemical signals present in their natural environment (i.e., stem cell niches). To increase our understanding about the interplay between stem cells and their resident microenvironments, biointerfaces have been developed as tools to study how these substrates can affect stem cell behaviors. This article aims to review recent developments on fabricating cell-instructive interfaces to control cell adhesion processes towards directing stem cell behavior. After an introduction on stem cells and their natural environment, static surfaces exhibiting predefined biochemical signals to probe the effect of chemical features on stem cell behaviors are discussed. In the third section, we discuss more complex dynamic platforms able to display biochemical cues with spatiotemporal control using on-off ligand display, reversible ligand display, and ligand mobility. In the last part of the review, we provide the reader with an outlook on future designs of biointerfaces. STATEMENT OF SIGNIFICANCE: Stem cells have great potential as treatments for many degenerative disorders prevalent in our aging societies. However, an ongoing challenge within their clinical translation is to promote stem cell mediated regeneration once they are transplanted in the body. Stem cells reside within our bodies where their behavior and function are regulated by interactions with their natural environment called the stem cell niche. To increase our understanding about the interplay between stem cells and their niche, 2D materials have been developed as tools to study how specific signals can affect stem cell behaviors. This article aims to review recent developments on fabricating cell-instructive interfaces to control cell adhesion processes towards directing stem cell behavior.

Targeting cancer stem cells via integrin β4

Integrins mediate cell-cell interactions and communication with the extracellular matrix (ECM). These transmembrane protein receptors allow binding between a cell and its surroundings, initiating a breadth of intracellular signaling resulting in proliferation, differentiation, survival, or migration. Such responses have made integrins an attractive target for cancer therapy. Self-renewing and highly tumorigenic cancer stem cells (CSCs) are most resistant to traditional radiation treatment and chemotherapy, and therefore may contribute directly to the metastasis and relapse of the disease. In both the 4T1 mouse metastatic mammary tumor model and SCC7 head and neck squamous cell carcinoma model, integrin β4 (ITGB4) was expressed on ALDH^high 4T1 and SCC7 CSCs. Using two immunological approaches, we targeted ITGB4 through 1) ITGB4 protein-pulsed dendritic cell (ITGB4-DC) vaccination or 2) via anti-CD3/anit-ITGB4 bispecific antibody (ITGB4 BiAb)-armed T cell adoptive transfer. These two therapies reduced ITGB4-expressing CSCs and inhibited local tumor growth and lung metastasis through ITGB4 specific cellular and humoral immune responses. Additionally, the combination of anti-PD-L1 immunotherapy with our two ITGB4-targeted approaches significantly improved treatment efficacy. We also found increased concentrations of serum IFN-γ and IL-6 in the 4T1 and SCC7 models which may help define future directions of this ITGB4-targeted study. Together, these results emphasize ITGB4 as a practical CSC immunological target with possible therapeutic benefits across tumor types with high ITGB4 expression.

Micromechanical force promotes aortic valvular calcification

OBJECTIVE

Calcified aortic valvular disease is known as an inflammation-related process related to force. The purpose of this study was to determine whether micromechanical force could induce valve calcification of porcine valvular interstitial cells and to examine the role of integrin αvβ3 in valvular calcification by using a novel method: magnetic twisting cytometry.

METHODS

Porcine valvular interstitial cells were cultured in vitro, and micromechanical force was applied to porcine valvular interstitial cells using magnetic twisting cytometry. Changes in calcification-related factors osteopontin and RUNX2 were detected. By using the calcification medium, the optimal magnetic twisting cytometry parameters for inducing valvular interstitial cell calcification were determined, and a magnetic twisting cytometry calcification promotion model was established. The role of αvβ3 in calcification was studied by using αvβ3 antagonists to block the function of αvβ3.

RESULTS

Reverse transcription polymerase chain reaction assays showed that the expression of osteopontin was enhanced 30 minutes after 25G-1Hz 5 minutes of stimulation. Western blotting assays showed that the expression of osteopontin and RUNX2 was upregulated 24 hours after 25G-1Hz 5 minutes of stimulation. The optimal magnetic twisting cytometry parameter for inducing porcine valvular interstitial cell calcification was 25G-2Hz for 10 minutes. The expression of osteopontin and RUNX2 decreased significantly after the addition of αvβ3 antagonist. Clinically, patients with bicuspid aortic valves had high expression of RUNX2 and β3 in the aortic valve, and β3 significantly correlated with RUNX2.

CONCLUSIONS

By using magnetic twisting cytometry, we established a porcine valvular interstitial cell calcification model by micromechanical force stimulation and obtained the optimal parameters. Integrin αvβ3 plays a key role in the aortic valve calcification process.

In vitro maturation using an agarose matrix with incorporated extracellular matrix proteins improves porcine oocyte developmental competence by enhancing cytoplasmic maturation

Here, we present a novel in vitro maturation (IVM) system comprising an agarose matrix supplemented with extracellular matrix (ECM) proteins for enhanced maturation of immature oocytes within cumulus-oocyte complexes (COCs) derived from porcine medium antral follicles (MAFs). Immunocytochemical analyses of integrin subunit α₂ , α₅ , α₆ , β₁ , and β₄ expression suggested that integrin α₂ β₁ , α₅ β₁ , α₆ β₁ , and α₆ β₄ play pivotal roles in IVM of porcine immature oocytes. Combinatorial supplementation of fibronectin interacting with integrin α₅ β₁ , collagen interacting with integrin α₂ β₁ , and laminin interacting with integrin α₆ β₁ and α₆ β₄ to the agarose matrix had no significant effect on nuclear maturation. However, the number of parthenogenetic embryos that developed into blastocysts increased when oocytes were matured using agarose IVM matrices supplemented with fibronectin, collagen, or laminin. Furthermore, significant increases in cytoplasmic maturation-related parameters (BMP15 level, cumulus cell expansion score, intra-oocyte ATP level, and index of cortical granule distribution) were observed in COCs matured in vitro using ECM protein-incorporated agarose matrices. Our data suggest that mature porcine oocytes with enhanced developmental competence and high-quality cytoplasm can be generated via IVM using agarose matrices supplemented with fibronectin, collagen, or laminin.

Extracellular Vesicles From the Human Natural Killer Cell Line NK3.3 Have Broad and Potent Anti-Tumor Activity

Natural killer (NK) cells are critical mediators of immune function, responsible for rapid destruction of tumor cells. They kill primarily through the release of granules containing potent cytolytic molecules. NK cells also release these molecules within membrane-bound exosomes and microvesicles - collectively known as extracellular vesicles (EV). Here we report the characterization and anti-tumor function of EVs isolated from NK3.3 cells, a well described clonal normal human NK cell line. We show that NK3.3 EVs contain the cytolytic molecules perforin, granzymes A and B, and granulysin, and an array of common EV proteins. We previously reported that the E3 ubiquitin ligase, natural killer lytic-associated molecule (NKLAM), is localized to NK granules and is essential for maximal NK killing; here we show it is present in the membrane of NK3.3 EVs. NK3.3-derived EVs also carry multiple RNA species, including miRNAs associated with anti-tumor activity. We demonstrate that NK3.3 EVs inhibit proliferation and induce caspase-mediated apoptosis and cell death of an array of both hematopoietic and non-hematopoietic tumor cell lines. This effect is tumor cell specific; normal cells are unaffected by EV treatment. By virtue of their derivation from a healthy donor and ability to be expanded to large numbers, NK3.3 EVs have the potential to be an effective, safe, and universal immunotherapeutic agent.

Detection of bladder cancer with aberrantly fucosylated ITGA3

We describe a simple, non-invasive assay to identify fucosylated-glycoisoform of integrin alpha-3 (ITGA3) directly from unprocessed urine. ITGA3 was detected directly from the urine of bladder cancer (BlCa) (n = 13) and benign prostatic hyperplasia (BPH) (n = 9) patients with the use of lectins coated on europium-doped-nanoparticles (Eu³⁺-NPs). Lectin Ulex europaeus agglutinin-I (UEA) showed enhanced binding with BlCa-derived ITGA3. The evaluation with individual samples showed that a glycovariant ITGA3-UEA assay could significantly discriminate BlCa from BPH patients (p = 0.007). The detection of aberrantly fucosylated-isoform of ITGA3 from urine can be used to distinguish BlCa from age-matched benign controls in a simple sandwich assay.

CD11c participates in triggering acute graft-versus-host disease during bone marrow transplantation

CD11c is a canonical dendritic cell (DC) marker with poorly defined functions in the immune system. Here, we found that blocking CD11c on human peripheral blood mononuclear cell‐derived DCs (MoDCs) inhibited the proliferation of CD4⁺ T cells and the differentiation into IFN‐γ‐producing T helper 1 (Th1) cells, which were critical in acute graft‐versus‐host disease (aGVHD) pathogenesis. Using allogeneic bone marrow transplantation (allo‐BMT) murine models, we consistently found that CD11c‐deficient recipient mice had alleviated aGVHD symptoms for the decreased IFN‐γ‐expressing CD4⁺ Th1 cells and CD8⁺ T cells. Transcriptional analysis showed that CD11c participated in several immune regulation functions including maintaining antigen presentation of APCs. CD11c‐deficient bone marrow‐derived DCs (BMDCs) impaired the antigen presentation function in coculture assay. Mechanistically, CD11c interacted with MHCII and Hsp90 and participated in the phosphorylation of Akt and Erk1/2 in DCs after multiple inflammatory stimulations. Therefore, CD11c played crucial roles in triggering aGVHD and might serve as a potential target for the prevention and treatment of aGVHD.

Across scales: novel insights into kidney health and disease by structural biology

Over the past decades, structural biology methods such as X-ray crystallography and cryo-electron microscopy have been increasingly used to study protein functions, molecular interactions, physiological processes, and disease mechanisms. This review outlines a selection of structural biology methods, highlights recent examples of how structural analyses have contributed to a more profound understanding of the machinery of life, and gives a perspective on how these methods can be applied to investigate functions of kidney molecules and pathogenic mechanisms of renal diseases.

Integrin αvβ5 heterodimer is a specific marker of human pancreatic beta cells

The identification of cell surface markers specific to pancreatic beta cells is important for both the study of islet biology and for investigating the pathophysiology of diseases in which this cell type is lost or damaged. Following analysis of publicly available RNAseq data, we identified specific integrin subunits, integrin αv and integrin β5, that were expressed in beta cells. This finding was further elaborated using immunofluorescence analysis of histological sections derived from donor human pancreas. Despite the broad expression of specific integrin subunits, we found that expression of integrin αvβ5 heterodimers was restricted to beta cells and that this complex persisted in islet remnants of some type 1 diabetic individuals from which insulin expression had been lost. This study identifies αvβ5 heterodimers as a novel cell surface marker of human pancreatic beta cells, a finding that will aid in the identification and characterisation of this important cell type.

Exogenous Integrin αIIbβ3 Inhibitors Revisited: Past, Present and Future Applications

The integrin αIIbβ3 is the most abundant integrin on platelets. Upon platelet activation, the integrin changes its conformation (inside-out signalling) and outside-in signalling takes place leading to platelet spreading, platelet aggregation and thrombus formation. Bloodsucking parasites such as mosquitoes, leeches and ticks express anticoagulant and antiplatelet proteins, which represent major sources of lead compounds for the development of useful therapeutic agents for the treatment of haemostatic disorders or cardiovascular diseases. In addition to hematophagous parasites, snakes also possess anticoagulant and antiplatelet proteins in their salivary glands. Two snake venom proteins have been developed into two antiplatelet drugs that are currently used in the clinic. The group of proteins discussed in this review are disintegrins, low molecular weight integrin-binding cysteine-rich proteins, found in snakes, ticks, leeches, worms and horseflies. Finally, we highlight various oral antagonists, which have been tested in clinical trials but were discontinued due to an increase in mortality. No new αIIbβ3 inhibitors are developed since the approval of current platelet antagonists, and structure-function analysis of exogenous disintegrins could help find platelet antagonists with fewer adverse side effects.

Integrin α10-Antibodies Reduce Glioblastoma Tumor Growth and Cell Migration

Simple Summary

Glioblastoma (GB) is the most common and most deadly form of brain tumor in adults which currently lacks effective treatments. Thus, there is a high need to identify new and effective ways to target the aggressive GB cells and treat the GB patients. In this study, we investigated the treatment effect of two antibodies that have been developed to target the protein integrin α10β1, which is present on the surface of GB cells. Our results show that the growth of GB tumor cells is reduced in the presence of the α10β1 antibodies. The treatment effect is demonstrated both in cell experiments and in an animal model. In addition, we found that the antibodies reduce the migration of the GB cells. We suggest that function-blocking antibodies targeting the integrin α10β1 is a promising new approach to treat glioblastoma patients.

Abstract

Glioblastoma (GB) is the most common and the most aggressive form of brain tumor in adults, which currently lacks efficient treatment strategies. In this study, we investigated the therapeutic effect of function-blocking antibodies targeting integrin α10β1 on patient-derived-GB cell lines in vitro and in vivo. The in vitro studies demonstrated significant inhibiting effects of the integrin α10 antibodies on the adhesion, migration, proliferation, and sphere formation of GB cells. In a xenograft mouse model, the effect of the antibodies on tumor growth was investigated in luciferase-labeled and subcutaneously implanted GB cells. As demonstrated by in vivo imaging analysis and caliper measurements, the integrin α10-antibodies significantly suppressed GB tumor growth compared to control antibodies. Immunohistochemical analysis of the GB tumors showed lower expression of the proliferation marker Ki67 and an increased expression of cleaved caspase-3 after treatment with integrin α10 antibodies, further supporting a therapeutic effect. Our results suggest that function-blocking antibody targeting integrin α10β1 is a promising therapeutic strategy for the treatment of glioblastoma.

Nanofibrous Tubular Three-Dimensional Platform for Single Dental Pulp Stem Cell Polarization

Dental pulp stem cells (DPSCs) are the primary stem cell source for regenerative endodontics. DPSCs need to undergo a polarization process and retain the permanent polarization status to perform the function of odontoblasts. However, the factors that control DPSC polarization and its underlying mechanism remain unknown. In this study, we established a unique nanofibrous tubular three-dimensional (3D) platform to explore DPSC polarization. The 3D platform has a "clean" background and confines one single DPSC in each microisland of the platform; therefore, it is capable of deciphering any signal that initiates or regulates DPSC polarization. Using the biomimetic platform, we identified that the nanofibrous tubular architecture is the crucial factor to initiate DPSC polarization. Dynamic morphological observation showed that the cellular process of the polarized DPSCs continuously extended and reached a plateau at 72 h. Meanwhile, Golgi apparatus, a cell polarization marker, continuously moved from a juxtanuclear region, passed the nucleus, and eventually settled down at a final position that was a few micrometers away from the nucleus. Inhibition of microfilament and microtubule polymerization demonstrated the indispensable role of cytoskeleton reorganization in modulating DPSC polarization. In addition, cell tension was involved in the regulation of DPSC polarization. The findings of this work expand the in-depth understanding of DPSC polarization, which helps design new bioinspired materials for regenerative endodontics.

Nanodiscs: A toolkit for membrane protein science

Membrane proteins are involved in numerous vital biological processes, including transport, signal transduction and the enzymes in a variety of metabolic pathways. Integral membrane proteins account for up to 30% of the human proteome and they make up more than half of all currently marketed therapeutic targets. Unfortunately, membrane proteins are inherently recalcitrant to study using the normal toolkit available to scientists, and one is most often left with the challenge of finding inhibitors, activators and specific antibodies using a denatured or detergent solubilized aggregate. The Nanodisc platform circumvents these challenges by providing a self-assembled system that renders typically insoluble, yet biologically and pharmacologically significant, targets such as receptors, transporters, enzymes, and viral antigens soluble in aqueous media in a native-like bilayer environment that maintain a target's functional activity. By providing a bilayer surface of defined composition and structure, Nanodiscs have found great utility in the study of cellular signaling complexes that assemble on a membrane surface. Nanodiscs provide a nanometer scale vehicle for the in vivo delivery of amphipathic drugs, therapeutic lipids, tethered nucleic acids, imaging agents and active protein complexes. This means for generating nanoscale lipid bilayers has spawned the successful use of numerous other polymer and peptide amphipathic systems. This review, in celebration of the Anfinsen Award, summarizes some recent results and provides an inroad into the current and historical literature.

Liver Matrix in Benign and Malignant Biliary Tract Disease

The extracellular matrix is a highly reactive scaffold formed by a wide array of multifunctional molecules, encompassing collagens and noncollagenous glycoproteins, proteoglycans, glycosaminoglycans, and polysaccharides. Besides outlining the tissue borders, the extracellular matrix profoundly regulates the behavior of resident cells by transducing mechanical signals, and by integrating multiple cues derived from the microenvironment. Evidence is mounting that changes in the biostructure of the extracellular matrix are instrumental for biliary repair. Following biliary damage and eventually, malignant transformation, the extracellular matrix undergoes several quantitative and qualitative modifications, which direct interactions among hepatic progenitor cells, reactive ductular cells, activated myofibroblasts and macrophages, to generate the ductular reaction. Herein, we will give an overview of the main molecular factors contributing to extracellular matrix remodeling in cholangiopathies. Then, we will discuss the structural alterations in terms of biochemical composition and physical stiffness featuring the "desmoplastic matrix" of cholangiocarcinoma along with their pro-oncogenic effects.

Integrins meet complement: The evolutionary tip of an iceberg orchestrating metabolism and immunity

Immunologists have recently realized that there is more to the classic innate immune sensor systems than just mere protection against invading pathogens. It is becoming increasingly clear that such sensors, including the inflammasomes, toll-like receptors, and the complement system, are heavily involved in the regulation of basic cell physiological processes and particularly those of metabolic nature. In fact, their "non-canonical" activities make sense as no system directing immune cell activity can perform such task without the need for energy. Further, many of these ancient immune sensors appeared early and concurrently during evolution, particularly during the developmental leap from the single-cell organisms to multicellularity, and therefore crosstalk heavily with each other. Here, we will review the current knowledge about the emerging cooperation between the major inter-cell communicators, integrins, and the cell-autonomous intracellularly and autocrine-active complement, the complosome, during the regulation of single-cell metabolism. LINKED ARTICLES: This article is part of a themed issue on Canonical and non-canonical functions of the complement system in health and disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.14/issuetoc.

Integrin Crosstalk Contributes to the Complexity of Signalling and Unpredictable Cancer Cell Fates

Integrins are heterodimeric cell surface receptors composed of α and β subunits that control adhesion, proliferation and gene expression. The integrin heterodimer binding to ligand reorganises the cytoskeletal networks and triggers multiple signalling pathways that can cause changes in cell cycle, proliferation, differentiation, survival and motility. In addition, integrins have been identified as targets for many different diseases, including cancer. Integrin crosstalk is a mechanism by which a change in the expression of a certain integrin subunit or the activation of an integrin heterodimer may interfere with the expression and/or activation of other integrin subunit(s) in the very same cell. Here, we review the evidence for integrin crosstalk in a range of cellular systems, with a particular emphasis on cancer. We describe the molecular mechanisms of integrin crosstalk, the effects of cell fate determination, and the contribution of crosstalk to therapeutic outcomes. Our intention is to raise awareness of integrin crosstalk events such that the contribution of the phenomenon can be taken into account when researching the biological or pathophysiological roles of integrins.

177Lu-labeled cyclic RGD peptide as an imaging and targeted radionuclide therapeutic agent in non-small cell lung cancer: Biological evaluation and preclinical study

Non-small cell lung carcinoma (NSCLC) is among the most lethal lung cancers responsible for 80-85% of death. α_vβ₃ integrin receptor subtype has been identified as a lung cancer biomarker since its expression correlates with tumor progression and metastasis. The extracellular domain of the receptor forms a binding site for RGD-based sequences. Therefore, specific targeting of α_vβ₃ integrin receptors by these short peptides can be an excellent candidate for cancer imaging and therapy. In this research, the radiolabeling of DOTA-E(cRGDfK)₂ with ¹⁷⁷Lu was efficiently implemented. The Log P value, in vivo, in vitro, metabolic stability, cellular uptake and specific binding of the radiopeptide was determined. The tumor targeting capacity and the therapeutic potential of the radiotracer was studied in A549 tumor-bearing mice. Imaging studies at different time intervals were performed by SPECT/CT. Radiochemical purity of more than 99% and Log P of -3.878 was obtained for ¹⁷⁷Lu-labelled peptide. Radiotracer showed favorable in vivo, in vitro and metabolic stability. The radiopeptide dissociation constant (K_d) was 15.07 nM. Radiopeptide specific binding was more than 95%. Biodistribution studies showed high accumulation of the radiopeptide in tumor and rapid excretion by urinary route. Maximum tumor uptake was at 4 h post-injection. Following administration of this radiopeptide to mice, not only tumor growth was suppressed, but significant tumor shrinkage was also observed. In conclusion, this radiopeptide can be employed for staging, follow-up imaging and as peptide receptor radionuclide therapeutic agent allowing efficient therapy for NSCLC and other cancers overexpressing α_vβ₃ integrin receptors.

Beta 1 integrin signaling mediates pancreatic ductal adenocarcinoma resistance to MEK inhibition

Pancreatic cancer, one of the deadliest human malignancies, has a dismal 5-year survival rate of 9%. KRAS is the most commonly mutated gene in pancreatic cancer, but clinical agents that directly target mutant KRAS are not available. Several effector pathways are activated downstream of oncogenic Kras, including MAPK signaling. MAPK signaling can be inhibited by targeting MEK1/2; unfortunately, this approach has been largely ineffective in pancreatic cancer. Here, we set out to identify mechanisms of MEK inhibitor resistance in pancreatic cancer. We optimized the culture of pancreatic tumor 3D clusters that utilized Matrigel as a basement membrane mimetic. Pancreatic tumor 3D clusters recapitulated mutant KRAS dependency and recalcitrance to MEK inhibition. Treatment of the clusters with trametinib, a MEK inhibitor, had only a modest effect on these cultures. We observed that cells adjacent to the basement membrane mimetic Matrigel survived MEK inhibition, while the cells in the interior layers underwent apoptosis. Our findings suggested that basement membrane attachment provided survival signals. We thus targeted integrin β1, a mediator of extracellular matrix contact, and found that combined MEK and integrin β1 inhibition bypassed trametinib resistance. Our data support exploring integrin signaling inhibition as a component of combination therapy in pancreatic cancer.

The Role of Integrin α4β7 Signaling in Human Immunodeficiency Virus-1 Pathogenesis and Viral Entry in Primary CD4+ T Cells As Revealed by Comparative Phosphoproteomic Signatures

Integrin α₄β_7, a CD4 independent receptor of human immunodeficiency virus-1 (HIV-1) gp120, defines a subset of CD4⁺T cells preferentially targeted by HIV. It is also considered as a promising therapeutic target for HIV-1 infection. Despite its role in HIV acquisition and disease progression, HIV-1-mediated integrin α₄β₇ signaling has not been elucidated so far. In view of this, we determined phosphoproteomic signatures of HIV-1 gp120 signaling as well as signaling mediated by the integrin α₄β₇ ligand, mucosal vascular addressin cell adhesion molecule-1 (MAdCAM-1), in primary CD4⁺ T cells. This is the first comprehensive report on MAdCAM-1 signaling, which is believed to enhance HIV-1 replication. Importantly, we identified proteins associated with both classical and nonclassical integrin functions. We observed that HIV-1 gp120 signaling is associated with proteins that have previously not been associated with HIV-1 pathogenesis and thus, need to be explored further. There was a significant overlap in proteins identified by both MAdCAM-1 and HIV-1 gp120 signaling, which most likely represents cellular processes triggered upon interaction of HIV-1 gp120 with integrin α₄β_7. Pathway analysis revealed enrichment of processes that could facilitate viral replication as well as viral entry through endocytosis. Although these results warrant independent replication and further validation, they suggest the presence of additional potential therapeutic targets. These results also suggest that combinatorial approaches for targeting both HIV-1 gp120 and MAdCAM-1 signaling may be necessary for efficient control of HIV-1 infection as well as novel innovation strategies in HIV therapeutics.

Putting the brakes on tumorigenesis with snake venom toxins: New molecular insights for cancer drug discovery

Cancer cells exhibit molecular characteristics that confer them different proliferative capacities and survival advantages to adapt to stress conditions, such as deregulation of cellular bioenergetics, genomic instability, ability to promote angiogenesis, invasion, cell dormancy, immune evasion, and cell death resistance. In addition to these hallmarks of cancer, the current cytostatic drugs target the proliferation of malignant cells, being ineffective in metastatic disease. These aspects highlight the need to identify promising therapeutic targets for new generations of anti-cancer drugs. Toxins isolated from snake venoms are a natural source of useful molecular scaffolds to obtain agents with a selective effect on cancer cells. In this article, we discuss the recent advances in the molecular mechanisms of nine classes of snake toxins that suppress the hallmarks of cancer by induction of oxidative phosphorylation dysfunction, reactive oxygen species-dependent DNA damage, blockage of extracellular matrix-integrin signaling, disruption of cytoskeleton network and inhibition of growth factor-dependent signaling. The possible therapeutic implications of toxin-based anti-cancer drug development are also highlighted.

Integrin Signaling in Glioma Pathogenesis: From Biology to Therapy

Integrins are a large family of transmembrane adhesion receptors, which play a key role in interactions of a cell with the surrounding stroma. Integrins are comprised of non-covalently linked α and β chains, which form heterodimeric receptor complexes. The signals from integrin receptors are combined with those originating from growth factor receptors and participate in orchestrating morphological changes of cells, organization of the cytoskeleton, stimulation of cell proliferation and rescuing cells from programmed cell death induced by extracellular matrix (ECM) detachment. Upon binding to specific ligands or ECM components, integrin dimers activate downstream signaling pathways, including focal adhesion kinase, phosphoinositide-3-kinase (PI3K) and AKT kinases, which regulate migration, invasion, proliferation and survival. Expression of specific integrins is upregulated in both tumor cells and stromal cells in a tumor microenvironment. Therefore, integrins became an attractive therapeutic target for many cancers, including the most common primary brain tumors-gliomas. In this review we provide an overview of the involvement of integrin signaling in glioma pathogenesis, formation of the tumor niche and brain tissue infiltration. We will summarize up-to-date therapeutic strategies for gliomas focused on interference with integrin ligand-receptor signaling.

Intracerebral Hemorrhage Induces Inflammatory Gene Expression in Peripheral Blood: Global Transcriptional Profiling in Intracerebral Hemorrhage Patients

To perform global transcriptome profiling using RNA-seq in the peripheral blood of intracerebral hemorrhage (ICH) patients. In 11 patients with ICH, peripheral blood was collected within 24 h of symptom onset or last known well, and a second blood draw occurred 72 h (±6) after the first. RNA-seq identified differentially expressed genes (DEGs) between the first and second samples. Biological pathway enrichment analysis was performed with Ingenuity® Pathway Analysis (IPA). A total of 16,640 genes were identified and 218 were significant DEGs after ICH (false discovery rate <0.1). IPA identified 97 disease and functional categories that were significantly upregulated (z-score >2) post-ICH; 46 categories were specifically related to immune cell activation, 22 to general cellular activation processes, and 4 to other inflammation-related responses. In the canonical pathway and network analysis, inflammatory mediators of particular importance included interleukin-8, NF-κB, ERK1/2, and members of the integrin class. ICH induced peripheral blood gene expression at 72 to 96 h compared with 0 to 24 h from symptom onset. DEGs that were highly expressed included those related to inflammation and activation of the immune response. Further research is needed to determine whether these changes affect outcomes and may represent new therapeutic targets.

Targeting Metastasis with Snake Toxins: Molecular Mechanisms

Metastasis involves the migration of cancer cells from a primary tumor to invade and establish secondary tumors in distant organs, and it is the main cause for cancer-related deaths. Currently, the conventional cytostatic drugs target the proliferation of malignant cells, being ineffective in metastatic disease. This highlights the need to find new anti-metastatic drugs. Toxins isolated from snake venoms are a natural source of potentially useful molecular scaffolds to obtain agents with anti-migratory and anti-invasive effects in cancer cells. While there is greater evidence concerning the mechanisms of cell death induction of several snake toxin classes on cancer cells; only a reduced number of toxin classes have been reported on (i.e., disintegrins/disintegrin-like proteins, C-type lectin-like proteins, C-type lectins, serinproteases, cardiotoxins, snake venom cystatins) as inhibitors of adhesion, migration, and invasion of cancer cells. Here, we discuss the anti-metastatic mechanisms of snake toxins, distinguishing three targets, which involve (1) inhibition of extracellular matrix components-dependent adhesion and migration, (2) inhibition of epithelial-mesenchymal transition, and (3) inhibition of migration by alterations in the actin/cytoskeleton network.

Knockdown of HMGN2 increases the internalization of Klebsiella pneumoniae by respiratory epithelial cells through the regulation of α5β1 integrin expression

Integrin receptors, a large family of adhesion receptors, are involved in the attachment of Klebsiella pneumoniae to respiratory epithelial cells, and subsequently cause the internalization of K. pneumoniae by host cells. Although a number of molecules have been reported to regulate the expression and activity of integrin receptors in respiratory epithelial cells, the specific underlying molecular mechanisms remain largely unknown. High mobility group nucleosomal binding domain 2 (HMGN2), a non-histone nuclear protein, is present in eukaryotic cells as a ubiquitous nuclear protein. Our previous studies have demonstrated that HMGN2 affects chromatin function and modulates the expression of antibacterial peptide in A549 cells exposed to lipopolysaccharide, which indicates the critical role of HMGN2 in innate immune responses. In addition, our cDNA microarray analysis suggested that HMGN2 knockdown induced the enhanced expression of α5β1 integrin in A549 cells. Therefore, we hypothesized that intercellular HMGN2 may mediate the internalization of K. pneumoniae by altering the expression of α5β1 integrin. Using the A549 cell line, we demonstrated that HMGN2 knockdown induced the increased expression of α5β1 integrin on cell membranes, which resulted in a significant increase in K. pneumoniae internalization. Further results revealed that HMGN2 silencing induced the expression of talin and the activation of α5β1 integrin, which led to actin polymerization following the phosphorylation of FAK and Src. This study suggests a possible therapeutic application for bacterial internalization by targeting HMGN2 in order to treat K. pneumoniae infection.

Integrins in development and cancer

The correct control of cell fate decisions is critical for metazoan development and tissue homeostasis. It is established that the integrin family of cell surface receptors regulate cell fate by mediating cell-cell and cell-extracellular matrix (ECM) interactions. However, our understanding of how the different family members control discrete aspects of cell biology, and how this varies between tissues and is temporally regulated, is still in its infancy. An emerging area of investigation aims to understand how integrins translate changes in tension in the surrounding microenvironment into biological responses. This is particularly pertinent due to changes in the mechanical properties of the ECM having been linked to diseases, such as cancer. In this review, we provide an overview of the roles integrins play in important developmental processes, such as proliferation, polarity, apoptosis, differentiation and maintenance of "stemness". We also discuss recent advances in integrin mechanobiology and highlight the involvement of integrins and aberrant ECM in cancer.