Distinct selectin ligands on colon carcinoma mucins can mediate pathological interactions among platelets, leukocytes, and endothelium

Immune Cell Migration to Cancer

Immune cell migration is required for the development of an effective and robust immune response. This elegant process is regulated by both cellular and environmental factors, with variables such as immune cell state, anatomical location, and disease state that govern differences in migration patterns. In all cases, a major factor is the expression of cell surface receptors and their cognate ligands. Rapid adaptation to environmental conditions partly depends on intrinsic cellular immune factors that affect a cell's ability to adjust to new environment. In this review, we discuss both myeloid and lymphoid cells and outline key determinants that govern immune cell migration, including molecules required for immune cell adhesion, modes of migration, chemotaxis, and specific chemokine signaling. Furthermore, we summarize tumor-specific elements that contribute to immune cell trafficking to cancer, while also exploring microenvironment factors that can alter these cellular dynamics within the tumor in both a pro and antitumor fashion. Specifically, we highlight the importance of the secretome in these later aspects. This review considers a myriad of factors that impact immune cell trajectory in cancer. We aim to highlight the immunotherapeutic targets that can be harnessed to achieve controlled immune trafficking to and within tumors.

Clinical guidelines for prevention and treatment of CAT in Japan and other countries

Cancer-associated thrombosis (CAT) is an important prognostic factor for an increasing number of cancer patients. Understanding of CAT among cancer care providers has grown in recent years, and guidelines for the prevention and treatment of CAT have been published in Japan and around the world. In this article, we introduce these major guidelines and discuss differences we identified between the Japanese guidelines and those of other countries, with a focus on problems and issues. Insurance coverage of low-molecular-weight heparin and indications for primary prevention with direct oral anticoagulants in particular require urgent consideration.

Research progress on the correlation between platelet aggregation and tumor progression

Platelets are generally considered as the main functional unit of the coagulation system. However, more and more studies have confirmed that platelets also have an important relationship with tumor progression. Tumor cells can utilize platelets to promote their own infiltration and hematogenous metastasis, and platelets are activated and aggregated in this process. Therefore, platelet aggregation may be a concomitant marker of tumor progression. This is of great significance for predicting tumor metastasis before timely treatments.

Characterization of MdpS: an in-depth analysis of a MUC5B-degrading protease from Streptococcus oralis

Oral biofilms, comprising hundreds of bacteria and other microorganisms on oral mucosal and dental surfaces, play a central role in oral health and disease dynamics. Streptococcus oralis, a key constituent of these biofilms, contributes significantly to the formation of which, serving as an early colonizer and microcolony scaffold. The interaction between S. oralis and the orally predominant mucin, MUC5B, is pivotal in biofilm development, yet the mechanism underlying MUC5B degradation remains poorly understood. This study introduces MdpS (Mucin Degrading Protease from Streptococcus oralis), a protease that extensively hydrolyses MUC5B and offers an insight into its evolutionary conservation, physicochemical properties, and substrate- and amino acid specificity. MdpS exhibits high sequence conservation within the species and also explicitly among early biofilm colonizing streptococci. It is a calcium or magnesium dependent serine protease with strict physicochemical preferences, including narrow pH and temperature tolerance, and high sensitivity to increasing concentrations of sodium chloride and reducing agents. Furthermore, MdpS primarily hydrolyzes proteins with O-glycans, but also shows activity toward immunoglobulins IgA1/2 and IgM, suggesting potential immunomodulatory effects. Significantly, MdpS extensively degrades MUC5B in the N- and C-terminal domains, emphasizing its role in mucin degradation, with implications for carbon and nitrogen sequestration for S. oralis or oral biofilm cross-feeding. Moreover, depending on substrate glycosylation, the amino acids serine, threonine or cysteine triggers the enzymatic action. Understanding the interplay between S. oralis and MUC5B, facilitated by MdpS, has significant implications for the management of a healthy eubiotic oral microenvironment, offering potential targets for interventions aimed at modulating oral biofilm composition and succession. Additionally, since MdpS does not rely on O-glycan removal prior to extensive peptide backbone hydrolysis, the MdpS data challenges the current model of MUC5B degradation. These findings emphasize the necessity for further research in this field.

Can targeted nanoparticles distinguish cancer metastasis from inflammation?

Targeting ligands have been widely used to increase the intratumoral accumulation of nanoparticles and their uptake by cancer cells. However, these ligands aim at targets that are often also upregulated in inflamed tissues. Here, we assessed the ability of targeted nanoparticles to distinguish metastatic cancer from sites of inflammation. Using common targeting ligands and a 60-nm liposome as a representative nanoparticle, we generated three targeted nanoparticle (NP) variants that targeted either fibronectin, folate, or αvβ3 integrin, whose deposition was compared against that of standard untargeted NP. Using fluorescently labeled NPs and ex vivo fluorescence imaging of organs, we assessed the deposition of the NPs into the lungs of mice modeling 4 different biological landscapes, including healthy lungs, aggressive metastasis in lungs, dormant/latent metastasis in lungs, and lungs with general pulmonary inflammation. Among the four NP variants, fibronectin-targeting NP and untargeted NP exhibited the highest deposition in lungs harboring aggressive metastases. However, the deposition of all targeted NP variants in lungs with metastasis was similar to the deposition in lungs with inflammation. Only the untargeted NP was able to exhibit higher deposition in metastasis than inflammation. Moreover, flow-cytometry analysis showed all NP variants accumulated predominantly in immune cells rather than cancer cells. For example, the number of NP+ macrophages and dendritic cells was 16-fold greater than NP+ cancer cells in the case of fibronectin-targeting NP. Overall, targeted NPs were unable to distinguish cancer metastasis from general inflammation, which may have clinical implications to the nanoparticle-mediated delivery of cancer drugs.

The role of tumor-platelet interplay and micro tumor thrombi during hematogenous tumor metastasis

BACKGROUND

In addition to their pivotal roles in coagulation and thrombosis, platelets are crucial in tumor progression, with plenty of clinical and experimental data demonstrating that the interplay of platelets and tumor cells is essential for hematogenous tumor metastasis. After detach from primary sites, tumor cells intravasate into the blood circulation becoming circulating tumor cells and induce platelet activation, aggregation and encasement around tumor cells to form micro tumor thrombi, which create a permissive tumor microenvironment for metastasis. Platelets in micro tumor thrombi protect tumor cells from immune surveillance and anoikis (detachment-triggered apoptosis) through various pathways, which are significant for tumor cell survival in the bloodstream. Moreover, platelets can facilitate tumor metastasis by expediting epithelial-mesenchymal transition (EMT), adhesion to the endothelium, angiogenesis, tumor proliferation processes and platelet-derived microvesicle (PMV) formation.

CONCLUSIONS

Here, we provide a synopsis of the current understanding of the formation of micro tumor thrombi and the role of micro tumor thrombi in tumor hematogenous metastasis based on the tumor-platelet interplay. We also highlight potential therapeutic strategies targeting platelets for tumor treatment, including cancer-associated platelet-targeted nanomedicines.

Cervical MUC5B and MUC5AC are Barriers to Ascending Pathogens During Pregnancy

CONTEXT

Cervical excision is a risk factor for preterm birth. This suggests that the cervix plays an essential role in the maintenance of pregnancy.

OBJECTIVE

We investigated the role of the cervix through proteomic analysis of cervicovaginal fluid (CVF) from pregnant women after trachelectomy surgery, the natural model of a lack of cervix.

METHODS

The proteome compositions of CVF in pregnant women after trachelectomy were compared with those in control pregnant women by liquid chromatography-tandem mass spectrometry and label-free relative quantification. MUC5B/AC expression in the human and murine cervices was analyzed by immunohistochemistry. Regulation of MUC5B/AC expression by sex steroids was assessed in primary human cervical epithelial cells. In a pregnant mouse model of ascending infection, Escherichia coli or phosphate-buffered saline was inoculated into the vagina at 16.5 dpc, and the cervices were collected at 17.5 dpc.

RESULTS

The expression of MUC5B/5AC in cervicovaginal fluid was decreased in pregnant women after trachelectomy concomitant with the anatomical loss of cervical glands. Post-trachelectomy women delivered at term when MUC5B/AC abundance was greater than the mean normalized abundance of the control. MUC5B levels in the cervix were increased during pregnancy in both humans and mice. MUC5B mRNA was increased by addition of estradiol in human cervical epithelial cells, whereas MUC5AC was not. In a pregnant mouse model of ascending infection, E. coli was trapped in the MUC5B/AC-expressing mucin of the cervix, and neutrophils were colocalized there.

CONCLUSION

Endocervical MUC5B and MUC5AC may be barriers to ascending pathogens during pregnancy.

Tumor Cell Capture Using Platelet-Based and Platelet-Mimicking Modified Human Serum Albumin Submicron Particles

The co-localization of platelets and tumor cells in hematogenous metastases has long been recognized. Interactions between platelets and circulating tumor cells (CTCs) contribute to tumor cell survival and migration via the vasculature into other tissues. Taking advantage of the interactions between platelets and tumor cells, two schemes, direct and indirect, were proposed to target the modified human serum albumin submicron particles (HSA-MPs) towards tumor cells. HSA-MPs were constructed by the Co-precipitation-Crosslinking-Dissolution (CCD) method. The anti-CD41 antibody or CD62P protein was linked to the HSA-MPs separately via 1-ethyl-3-(-3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) EDC/NHS chemistry. The size of modified HSA-MPs was measured at approximately 1 µm, and the zeta potential was around -24 mV. Anti-CD41-HSA-MPs adhered to platelets as shown by flowcytometry and confocal laser scanning microscopy. In vitro, we confirmed the adhesion of platelets to tumor lung carcinoma cells A549 under shearing conditions. Higher cellular uptake of anti-CD41-HSA-MPs in A549 cells was found in the presence of activated platelets, suggesting that activated platelets can mediate the uptake of these particles. RNA-seq data in the Cancer Cell Lineage Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) database showed the expression of CD62P ligands in different types of cancers. Compared to the non-targeted system, CD62P-HSA-MPs were found to have higher cellular uptake in A549 cells. Our results suggest that the platelet-based and platelet-mimicking modified HSA-MPs could be promising options for tracking metastatic cancer.

Potential Roles of Selectins in Periodontal Diseases and Associated Systemic Diseases: Could They Be Targets for Immunotherapy?

Periodontal diseases are predisposing factors to the development of many systemic disorders, which is often initiated via leukocyte infiltration and vascular inflammation. These diseases could significantly affect human health and quality of life. Hence, it is vital to explore effective therapies to prevent disease progression. Periodontitis, which is characterized by gingival bleeding, disruption of the gingival capillary's integrity, and irreversible destruction of the periodontal supporting bone, appears to be caused by overexpression of selectins in periodontal tissues. Selectins (P-, L-, and E-selectins) are vital members of adhesion molecules regulating inflammatory and immune responses. They are mainly located in platelets, leukocytes, and endothelial cells. Furthermore, selectins are involved in the immunopathogenesis of vascular inflammatory diseases, such as cardiovascular disease, diabetes, cancers, and so on, by mediating leukocyte recruitment, platelet activation, and alteration of endothelial barrier permeability. Therefore, selectins could be new immunotherapeutic targets for periodontal disorders and their associated systemic diseases since they play a crucial role in immune regulation and endothelium dysfunction. However, the research on selectins and their association with periodontal and systemic diseases remains limited. This review aims to discuss the critical roles of selectins in periodontitis and associated systemic disorders and highlights the potential of selectins as therapeutic targets.

Lysosomal cathepsin D mediates endogenous mucin glycodomain catabolism in mammals

Mucins are functionally implicated in a range of human pathologies, including cystic fibrosis, influenza, bacterial endocarditis, gut dysbiosis, and cancer. These observations have motivated the study of mucin biosynthesis as well as the development of strategies for inhibition of mucin glycosylation. Mammalian pathways for mucin catabolism, however, have remained underexplored. The canonical view, derived from analysis of N-glycoproteins in human lysosomal storage disorders, is that glycan degradation and proteolysis occur sequentially. Here, we challenge this view by providing genetic and biochemical evidence supporting mammalian proteolysis of heavily O-glycosylated mucin domains without prior deglycosylation. Using activity screening coupled with mass spectrometry, we ascribed mucin-degrading activity in murine liver to the lysosomal protease cathepsin D. Glycoproteomics of substrates digested with purified human liver lysosomal cathepsin D provided direct evidence for proteolysis within densely O-glycosylated domains. Finally, knockout of cathepsin D in a murine model of the human lysosomal storage disorder neuronal ceroid lipofuscinosis 10 resulted in accumulation of mucins in liver-resident macrophages. Our findings imply that mucin-degrading activity is a component of endogenous pathways for glycoprotein catabolism in mammalian tissues.

Fluid shear stress influences invasiveness of HeLa cells through the induction of autophagy

Extravasation of metastatic cells from the blood or lymphatic circulation and formation of secondary tumor at a distant site is a key step of cancer metastasis. In this study, we report the role of hemodynamic shear stresses in fostering the release of pro-extravasation factors through the mediation of autophagy in cervical cancer HeLa cells. HeLa cells were exposed to physiological shear stress through the microfluidic approach adapted in our previous study on the role of hemodynamic shear stresses in survival of HeLa cells. Herein, an optimum number of passes through a cylindrical microchannel was chosen such that the viability of cells was unaffected by shear. Shear-exposed cells were then probed for their invasive and migratory potential through in vitro migration and invasion assays. The dependence of cancer cells on mechanically-induced autophagy for extravasation was further assessed through protein expression studies. Our results suggest that shear stress upregulates autophagy, which fosters paxillin turnover thereby leading to enhanced focal adhesion disassembly and in turn enhanced cell migration. Concurrently, shear stress-induced secretion of pro-invasive factors like MMP-2 and IL-6 were found to be autophagy-dependent thereby hinting at autophagy as a potential therapeutic target in metastatic cancer. Proposed model for mechano-autophagic modulation of extravasation.

Targeted Inhibition of Tumor Inflammation and Tumor-Platelet Crosstalk by Nanoparticle-Mediated Drug Delivery Mitigates Cancer Metastasis

Sowing malignant cells (the "seeds" of metastasis) to engraft secondary sites requires a conducive premetastatic niche (PMN, the "soil" of metastasis). Inflammation and tumor associated platelet (TAP) has been hijacked by primary tumors to induce PMN "soil" in distant organs, as well as facilitate the dissemination of "seeds". This study reports a combinatory strategy with activated platelet-targeting nanoparticles to aim at the dynamic process of entire cancer metastasis, which exerts robust antimetastasis efficacy by simultaneously inhibiting tumor inflammation and tumor-platelet crosstalk. Our results reveals that the PSN peptide (a P-selectin-targeting peptide) modification enriched the accumulation of nanoparticles in primary tumor, pulmonary PMN, and metastases via capturing activated platelet. Such characteristics contribute to the efficient inhibition on almost every crucial and consecutive step of the metastasis cascade by retarding epithelial-mesenchymal transition (EMT) progression within tumors, specifically blocking the tumor-platelet crosstalk to remove the platelets "protective shield" around disseminated "seeds", and reversing the inflammatory microenvironment to interfere with the "soil" formation. Consisting of inflammation inhibiting and TAP impeding nanoparticles, this approach prominently reduces various metastasis in abscopal lung, including spontaneous metastasis, disseminated tumor cells metastasis, and post-operative metastasis. This work provides a generalizable nanoplatform of parallel inflammation disturbance and tumor-TAP crosstalk blockade to resist metastatic tumors.

Comparison of the uptake of untargeted and targeted immunostimulatory nanoparticles by immune cells in the microenvironment of metastatic breast cancer

To alter the immunosuppressive tumor microenvironment (TME), we developed an immunostimulatory nanoparticle (NP) to reprogram a tumor's dysfunctional and inhibitory antigen-presenting cells (APCs) into properly activated APCs that stimulate tumor-reactive cytotoxic T cells. Importantly, systemic delivery allowed NPs to efficiently utilize the entire microvasculature and gain access into the majority of the perivascular TME, which coincided with the APC-rich tumor areas leading to uptake of the NPs predominantly by APCs. In this work, a 60 nm NP was loaded with a STING agonist, which triggered robust production of interferon β, resulting in activation of APCs. In addition to untargeted NPs, we employed 'mainstream' ligands targeting fibronectin, αvβ3 integrin and P-selectin that are commonly used to direct nanoparticles to tumors. Using the 4T1 mouse model, we assessed the microdistribution of the four NP variants in the tumor immune microenvironment in three different breast cancer landscapes, including primary tumor, early metastasis, and late metastasis. The different NP variants resulted in variable uptake by immune cell subsets depending on the organ and tumor stage. Among the NP variants, therapeutic studies indicated that the untargeted NPs and the integrin-targeting NPs exhibited a remarkable short- and long-term immune response and long-lasting antitumor effect.

Bidirectional Interaction Between Cancer Cells and Platelets Provides Potential Strategies for Cancer Therapies

Platelets are essential components in the tumor microenvironment. For decades, clinical data have demonstrated that cancer patients have a high risk of thrombosis that is associated with adverse prognosis and decreased survival, indicating the involvement of platelets in cancer progression. Increasing evidence confirms that cancer cells are able to induce production and activation of platelets. Once activated, platelets serve as allies of cancer cells in tumor growth and metastasis. They can protect circulating tumor cells (CTCs) against the immune system and detachment-induced apoptosis while facilitating angiogenesis and tumor cell adhesion and invasion. Therefore, antiplatelet agents and platelet-based therapies should be developed for cancer treatment. Here, we discuss the mechanisms underlying the bidirectional cancer-platelet crosstalk and platelet-based therapeutic approaches.

Mucin1 and Mucin16: Therapeutic Targets for Cancer Therapy

The mucin (MUC) family is a group of highly glycosylated macromolecules that are abundantly expressed in mammalian epithelial cells. MUC proteins contribute to the formation of the mucus barrier and thus have protective functions against infection. Interestingly, some MUC proteins are aberrantly expressed in cancer cells and are involved in cancer development and progression, including cell growth, proliferation, the inhibition of apoptosis, chemoresistance, metabolic reprogramming, and immune evasion. With their unique biological and structural features, MUC proteins have been considered promising therapeutic targets and also biomarkers for human cancer. In this review, we discuss the biological roles of the transmembrane mucins MUC1 and MUC16 in the context of hallmarks of cancer and current efforts to develop MUC1- and MUC16-targeted therapies.

Platelet-Cancer Interplay: Molecular Mechanisms and New Therapeutic Avenues

Although platelets are critically involved in thrombosis and hemostasis, experimental and clinical evidence indicate that platelets promote tumor progression and metastasis through a wide range of physical and functional interactions between platelets and cancer cells. Thrombotic and thromboembolic events are frequent complications in patients with solid tumors. Hence, cancer modulates platelet function by directly inducing platelet-tumor aggregates and triggering platelet granule release and altering platelet turnover. Also, platelets enhance tumor cell dissemination by activating endothelial cell function and recruiting immune cells to primary and metastatic tumor sites. In this review, we summarize current knowledge on the complex interactions between platelets and tumor cells and the host microenvironment. We also critically discuss the potential of anti-platelet agents for cancer prevention and treatment.

Platelets and Metastasis: New Implications of an Old Interplay

During the process of hematogenous metastasis, tumor cells interact with platelets and their precursors megakaryocytes, providing a selection driver for the metastatic phenotype. Cancer cells have evolved a plethora of mechanisms to engage platelet activation and aggregation. Platelet coating of tumor cells in the blood stream promotes the successful completion of multiple steps of the metastatic cascade. Along the same lines, clinical evidence suggests that anti-coagulant therapy might be associated with reduced risk of metastatic disease and better prognosis in cancer patients. Here, we review experimental and clinical literature concerning the contribution of platelets and megakaryocytes to cancer metastasis and provide insights into the clinical relevance of anti-coagulant therapy in cancer treatment.

Selectins-The Two Dr. Jekyll and Mr. Hyde Faces of Adhesion Molecules-A Review

Selectins belong to a group of adhesion molecules that fulfill an essential role in immune and inflammatory responses and tissue healing. Selectins are glycoproteins that decode the information carried by glycan structures, and non-covalent interactions of selectins with these glycan structures mediate biological processes. The sialylated and fucosylated tetrasaccharide sLe^x is an essential glycan recognized by selectins. Several glycosyltransferases are responsible for the biosynthesis of the sLe^x tetrasaccharide. Selectins are involved in a sequence of interactions of circulated leukocytes with endothelial cells in the blood called the adhesion cascade. Recently, it has become evident that cancer cells utilize a similar adhesion cascade to promote metastases. However, like Dr. Jekyll and Mr. Hyde’s two faces, selectins also contribute to tissue destruction during some infections and inflammatory diseases. The most prominent function of selectins is associated with the initial stage of the leukocyte adhesion cascade, in which selectin binding enables tethering and rolling. The first adhesive event occurs through specific non-covalent interactions between selectins and their ligands, with glycans functioning as an interface between leukocytes or cancer cells and the endothelium. Targeting these interactions remains a principal strategy aimed at developing new therapies for the treatment of immune and inflammatory disorders and cancer. In this review, we will survey the significant contributions to and the current status of the understanding of the structure of selectins and the role of selectins in various biological processes. The potential of selectins and their ligands as therapeutic targets in chronic and acute inflammatory diseases and cancer will also be discussed. We will emphasize the structural characteristic of selectins and the catalytic mechanisms of glycosyltransferases involved in the biosynthesis of glycan recognition determinants. Furthermore, recent achievements in the synthesis of selectin inhibitors will be reviewed with a focus on the various strategies used for the development of glycosyltransferase inhibitors, including substrate analog inhibitors and transition state analog inhibitors, which are based on knowledge of the catalytic mechanism.

Mechanistic and Functional Shades of Mucins and Associated Glycans in Colon Cancer

Mucus serves as the chief protective barrier against pathogenic and mechanical insults in respiratory, gastrointestinal, and urogenital tracts. Altered mucin expression, the major component of mucus, in conjunction with differential glycosylation has been strongly associated with both benign and malignant pathologies of colon. Mucins and their associated glycans arbitrate their impact sterically as well as mechanically by altering molecular and microbial spectrum during pathogenesis. Mucin expression in normal and pathological conditions is regulated by nonspecific (dietary factors and gut microbiota) and specific (epigenetic and transcriptional) modulators. Further, recent studies highlight the impact of altering mucin glycome (cancer-associated carbohydrate antigens including Tn, Sialyl-Tn, Sialyl-Lew A, and Sialyl-Lewis X) on host immunomodulation, antitumor immunity, as well as gut microbiota. In light of emerging literature, the present review article digs into the impact of structural organization and of expressional and glycosylation alteration of mucin family members on benign and malignant pathologies of colorectal cancer.

Galactosaminoglycans: Medical Applications and Drawbacks

Galactosaminoglycans (GalAGs) are sulfated glycans composed of alternating N-acetylgalactosamine and uronic acid units. Uronic acid epimerization, sulfation patterns and fucosylation are modifications observed on these molecules. GalAGs have been extensively studied and exploited because of their multiple biomedical functions. Chondroitin sulfates (CSs), the main representative family of GalAGs, have been used in alternative therapy of joint pain/inflammation and osteoarthritis. The relatively novel fucosylated chondroitin sulfate (FCS), commonly found in sea cucumbers, has been screened in multiple systems in addition to its widely studied anticoagulant action. Biomedical properties of GalAGs are directly dependent on the sugar composition, presence or lack of fucose branches, as well as sulfation patterns. Although research interest in GalAGs has increased considerably over the three last decades, perhaps motivated by the parallel progress of glycomics, serious questions concerning the effectiveness and potential side effects of GalAGs have recently been raised. Doubts have centered particularly on the beneficial functions of CS-based therapeutic supplements and the potential harmful effects of FCS as similarly observed for oversulfated chondroitin sulfate, as a contaminant of heparin. Unexpected components were also detected in CS-based pharmaceutical preparations. This review therefore aims to offer a discussion on (1) the current and potential therapeutic applications of GalAGs, including those of unique features extracted from marine sources, and (2) the potential drawbacks of this class of molecules when applied to medicine.

Case of internal jugular vein thrombosis and fever: Lemierre's syndrome or Trousseau's syndrome?

Internal jugular vein thrombosis is a rare critical cardiovascular emergency, which has potential catastrophic clinical outcomes by resulting in stroke and pulmonary embolism. Several etiologies have been reported; however, there are limited data on Lemierre's and Trousseau's syndromes, which are both rare conditions with advanced disease progression and poor clinical outcomes. Lemierre's syndrome may present with typical progressively infectious symptoms and signs, including sore throat, neck mass, and fever, whereas Trousseau's syndrome may present with thrombophlebitis and painful edema. Without antibiotic agents controlling the infection, the condition of patients with Lemierre's syndrome may progress to sepsis or septic shock. The infection pattern plays an important role for differential diagnosis. Herein, we describe the case of a 46-year-old woman presenting with atypical symptoms of Trousseau's syndrome mimicking Lemierre's syndrome. Laboratory analysis including protein C, protein S, rheumatoid factor, and antinuclear antibody ruled out hypercoagulopathy and autoimmune vasculitis. Abdominal computed tomography and panendoscopy revealed ulcerative tumor at the antrum. Pathological examination confirmed the presence of signet-ring cell adenocarcinoma. We highlight the clinical features and etiologies of internal jugular vein thrombosis, especially in Lemierre's syndrome and Trousseau's syndrome, to aid physicians in making an early diagnosis and providing timely management.

Glycosylation in the Tumor Microenvironment: Implications for Tumor Angiogenesis and Metastasis

Just as oncogene activation and tumor suppressor loss are hallmarks of tumor development, emerging evidence indicates that tumor microenvironment-mediated changes in glycosylation play a crucial functional role in tumor progression and metastasis. Hypoxia and inflammatory events regulate protein glycosylation in tumor cells and associated stromal cells in the tumor microenvironment, which facilitates tumor progression and also modulates a patient's response to anti-cancer therapeutics. In this review, we highlight the impact of altered glycosylation on angiogenic signaling and endothelial cell adhesion, and the critical consequences of these changes in tumor behavior.

Integrin Signaling in Cancer: Mechanotransduction, Stemness, Epithelial Plasticity, and Therapeutic Resistance

Integrins mediate cell adhesion and transmit mechanical and chemical signals to the cell interior. Various mechanisms deregulate integrin signaling in cancer, empowering tumor cells with the ability to proliferate without restraint, to invade through tissue boundaries, and to survive in foreign microenvironments. Recent studies have revealed that integrin signaling drives multiple stem cell functions, including tumor initiation, epithelial plasticity, metastatic reactivation, and resistance to oncogene- and immune-targeted therapies. Here, we discuss the mechanisms leading to the deregulation of integrin signaling in cancer and its various consequences. We place emphasis on novel functions, determinants of context dependency, and mechanism-based therapeutic opportunities.

Imaging breast cancer using a dual-ligand nanochain particle

Nanoparticles often only exploit the upregulation of a receptor on cancer cells to enhance intratumoral deposition of therapeutic and imaging agents. However, a single targeting moiety assumes that a tumor is homogenous and static. Tumoral microenvironments are both heterogenous and dynamic, often displaying variable spatial and temporal expression of targetable receptors throughout disease progression. Here, we evaluated the in vivo performance of an iron oxide nanoparticle in terms of targeting and imaging of orthotropic mouse models of aggressive breast tumors. The nanoparticle, a multi-component nanochain, was comprised of 3–5 iron oxide nanoparticles chemically linked in a linear chain. The nanoparticle’s surface was decorated with two types of ligands each targeting two different upregulated biomarkers on the tumor endothelium, P-selectin and fibronectin. The nanochain exhibited improved tumor deposition not only through vascular targeting but also through its elongated structure. A single-ligand nanochain exhibited a ~2.5-fold higher intratumoral deposition than a spherical nanoparticle variant. Furthermore, the dual-ligand nanochain exhibited higher consistency in generating detectable MR signals compared to a single-ligand nanochain. Using a 7T MRI, the dual-ligand nanochains exhibited highly detectable MR signal within 3h after injection in two different animal models of breast cancer.

Cancer-Associated Thrombosis: An Overview of Mechanisms, Risk Factors, and Treatment

Cancer-associated thrombosis is a major cause of mortality in cancer patients, the most common type being venous thromboembolism (VTE). Several risk factors for developing VTE also coexist with cancer patients, such as chemotherapy and immobilisation, contributing to the increased risk cancer patients have of developing VTE compared with non-cancer patients. Cancer cells are capable of activating the coagulation cascade and other prothrombotic properties of host cells, and many anticancer treatments themselves are being described as additional mechanisms for promoting VTE. This review will give an overview of the main thrombotic complications in cancer patients and outline the risk factors for cancer patients developing cancer-associated thrombosis, focusing on VTE as it is the most common complication observed in cancer patients. The multiple mechanisms involved in cancer-associated thrombosis, including the role of anticancer drugs, and a brief outline of the current treatment for cancer-associated thrombosis will also be discussed.

Antithrombotic Agents and Cancer

Platelet activation is the first response to tissue damage and, if unrestrained, may promote chronic inflammation-related cancer, mainly through the release of soluble factors and vesicles that are rich in genetic materials and proteins. Platelets also sustain cancer cell invasion and metastasis formation by fostering the development of the epithelial-mesenchymal transition phenotype, cancer cell survival in the bloodstream and arrest/extravasation at the endothelium. Furthermore, platelets contribute to tumor escape from immune elimination. These findings provide the rationale for the use of antithrombotic agents in the prevention of cancer development and the reduction of metastatic spread and mortality. Among them, low-dose aspirin has been extensively evaluated in both preclinical and clinical studies. The lines of evidence have been considered appropriate to recommend the use of low-dose aspirin for primary prevention of cardiovascular disease and colorectal cancer by the USA. Preventive Services Task Force. However, two questions are still open: (i) the efficacy of aspirin as an anticancer agent shared by other antiplatelet agents, such as clopidogrel; (ii) the beneficial effect of aspirin improved at higher doses or by the co-administration of clopidogrel. This review discusses the latest updates regarding the mechanisms by which platelets promote cancer and the efficacy of antiplatelet agents.

Hsa-miR-370 inhibited P-selectin-induced cell adhesion in human colon adenocarcinoma cells

Sialyl Lewis x (sLe^x) is a minimal recognition motif for ligands of P-selectin and plays an important role in tumor cell adhesion and migration. Thus, targeting sLe^x could be an effective method to prevent tumor metastasis. In this study, we aimed to identify a microRNA (miRNA) which is capable to suppress the expression of sLe^x. MicroRNAs which may target ST3GAL4 were predicted by the online tools. Colo 320 HSR human colon adenocarcinoma cells were employed. The transcriptional and translational levels of ST3GAL4 were evaluated by western blotting and Real-time quantitative polymerase chain reaction. Cell adhesion and spread were assessed with or without hsa-miR-370 treatment. It was shown that hsa-miR-370 inhibited the expression of sLe^x in colo-320 cells, which repressed the binding of P-selectin, and led to reduced cell attachment and spread. Our results found that P-selectin-induced elevations of p-p38 and p-PI3K levels were significantly inhibited by hsa-miR-370, indicating that repressed sLe^x level is able to reduce the P-selectin binding and therefore eliminating the P-selectin-induced activation of p38 and PI3K signaling. In conclusion, we found that hsa-miR-370 specifically inhibits the expression of sLe^x, represses cell adhesion and spreading in colo-320 cells. Our study provides a possible effective treatment against tumor invasion.

Cancer and platelet crosstalk: opportunities and challenges for aspirin and other antiplatelet agents

Platelets have long been recognized as key players in hemostasis and thrombosis; however, growing evidence suggests that they are also significantly involved in cancer, the second leading cause of mortality worldwide. Preclinical and clinical studies showed that tumorigenesis and metastasis can be promoted by platelets through a wide variety of crosstalk between platelets and cancer cells. For example, cancer changes platelet behavior by directly inducing tumor-platelet aggregates, triggering platelet granule and extracellular vesicle release, altering platelet phenotype and platelet RNA profiles, and enhancing thrombopoiesis. Reciprocally, platelets reinforce tumor growth with proliferation signals, antiapoptotic effect, and angiogenic factors. Platelets also activate tumor invasion and sustain metastasis via inducing an invasive epithelial-mesenchymal transition phenotype of tumor cells, promoting tumor survival in circulation, tumor arrest at the endothelium, and extravasation. Furthermore, platelets assist tumors in evading immune destruction. Hence, cancer cells and platelets maintain a complex, bidirectional communication. Recently, aspirin (acetylsalicylic acid) has been recognized as a promising cancer-preventive agent. It is recommended at daily low dose by the US Preventive Services Task Force for primary prevention of colorectal cancer. The exact mechanisms of action of aspirin in chemoprevention are not very clear, but evidence has emerged that suggests a platelet-mediated effect. In this article, we will introduce how cancer changes platelets to be more cancer-friendly and highlight advances in the modes of action for aspirin in cancer prevention. We also discuss the opportunities, challenges, and opposing viewpoints on applying aspirin and other antiplatelet agents for cancer prevention and treatment.

Precise targeting of cancer metastasis using multi-ligand nanoparticles incorporating four different ligands

Metastasis displays a highly heterogeneous cellular population with cancer cells continuously evolving. As a result, a single-ligand nanoparticle cannot account for the continuously changing expression of targetable biomarkers over time and space. To effectively direct nanoparticles to metastasis, we developed a multi-ligand nanoparticle by using four different types of ligands on the same nanoparticle that target biomarkers on the endothelium associated with metastatic disease. These vascular targets included αvβ3 integrin, P-selectin, EGFR and fibronectin. Using terminal and in vivo imaging studies, the targeting performance of the multi-ligand nanoparticles was compared to the single-ligand nanoparticle variants. All four single-ligand nanoparticle variants achieved significant targeting of lung metastasis in the 4T1 mouse model of breast cancer metastasis with about 2.5% of the injected dose being deposited into metastasis. A dual-ligand nanoparticle resulted in a nearly 2-fold higher deposition into lung metastases than its single-ligand counterparts. The multi-ligand nanoparticle significantly outperformed its targeting nanoparticle counterparts achieving a deposition of ∼7% of its injected nanoparticles into lung metastases. Using the high sensitivity of radionuclide imaging, PET imaging showed that a multi-ligand nanoparticle labeled with [18F]fluoride was able to precisely target metastatic disease at its very early stage of development in three different animal models of metastatic breast cancer.

Analysis of preoperative blood platelet parameters in terms of diversity of epithelial ovarian cancer

Smouldering inflammation, thrombocytosis, and platelet hyper-reactivity are linked to malignancy. The relationships between preoperative diagnostic blood morphology parameters and cancer have been the focus of much interest, because some of these parameters are correlated with advanced cancer stages and poor patient survival rates. This study aimed to perform an observational, retrospective analysis of the intradiversity of blood platelet parameters in patients with different International Federation of Gynaecology and Obstetrics (FIGO) stages and different histological types of epithelial ovarian carcinomas (EOC), and also an analysis of the overall survival rate.In all, 94 EOC patients were included in this analysis (23 mucinous, 33 serous, 20 undifferentiated, 14 endometrioid, and 4 clear cell carcinoma cases). Peripheral blood samples were collected and analyzed before drug or surgical treatment.The platelet-to-neutrophil ratio (PNR) was related to the histological type of EOC, particularly mucinous carcinoma. In patients with mucinous cancer, the PNR was significantly lower compared with patients with nonmucinous cancer, and this parameter distinguished between mucinous and nonmucinous groups of patients (area under receiver-operating characteristic [ROC] curve 0.721 ± .056; sensitivity 82.6%; specificity 61%; P < .001; ROC analysis), regardless of the FIGO stage. Moreover, elevated PNR values were correlated with lower survival rate of EOC patients.The reduced PNR, similar to the lower level of cancer antigen 125, is characteristic for mucinous ovarian carcinoma patients. Moreover, elevated PNR index might correlate with poor survival of patients.

Molecular background of the regional lymph node metastasis of gastric cancer

Gastric cancer (GC) is one of the deadliest types of cancer in the world. Lymph node (LN) metastasis is a complex and malignant behavior of GC, involving a sequence of biological processes, including decreased adherence to adjacent cells, extracellular matrix (ECM) degradation and lymphatic channel permeation. LN metastasis is directly associated with the treatment response, local recurrence and long-term survival of patients with GC. Therefore, the molecular mechanisms of LN metastasis in GC development require further investigation. Recently, a large number of clinical studies have focused on the molecular mechanisms and biological markers of tumor invasion and metastasis. However, few articles have broadly summarized LN metastasis in GC, and the molecular mechanisms of LN metastasis are not yet fully understood. In the present review, the molecular mechanisms of LN metastasis in GC will be discussed, including the following aspects: Cell adhesion and movement, ECM degradation, new vessel formation, and molecular pattern differences between metastatic LNs and the primary tumor. This review may lead to a better understanding of LN metastasis in GC, and the identification of new diagnostic markers.

Dynamic biochemical tissue analysis detects functional L-selectin ligands on colon cancer tissues

A growing body of evidence suggests that L-selectin ligands presented on circulating tumor cells facilitate metastasis by binding L-selectin presented on leukocytes. Commonly used methods for detecting L-selectin ligands on tissues, e.g., immunostaining, are performed under static, no-flow conditions. However, such analysis does not assay for functional L-selectin ligands, specifically those ligands that promote adhesion under shear flow conditions. Recently our lab developed a method, termed dynamic biochemical tissue analysis (DBTA), to detect functional selectin ligands in situ by probing tissues with L-selectin-coated microspheres under hemodynamic flow conditions. In this investigation, DBTA was used to probe human colon tissues for L-selectin ligand activity. The detection of L-selectin ligands using DBTA was highly specific. Furthermore, DBTA reproducibly detected functional L-selectin ligands on diseased, e.g., cancerous or inflamed, tissues but not on noncancerous tissues. In addition, DBTA revealed a heterogeneous distribution of functional L-selectin ligands on colon cancer tissues. Most notably, detection of L-selectin ligands by immunostaining using HECA-452 antibody only partially correlated with functional L-selectin ligands detected by DBTA. In summation, the results of this study demonstrate that DBTA detects functional selectin ligands to provide a unique characterization of pathological tissue.

Cancer and the metastatic substrate

Seventy percent of cancer patients have detectable metastases when they receive a diagnosis and 90% of cancer deaths result from metastases. These two facts emphasise the urgency for research to study the mechanisms and processes that enable metastasis. We need to develop a greater understanding of the cellular and molecular mechanisms that cause metastasis and also we need to do more. We must also consider the micro- and macro-environmental factors that influence this disease. Studying this environmental context has led us to update the ‘seed and soil’ hypothesis which dates back to the 19th century. This theory describes cancerous cells as seeds and the substrate as the soil in target organs though this may seem antiquated. Nonetheless, the tissue specificity that researchers have recently observed in metastatic colonisation supports the validity of the seed and soil theory. We now know that the metastatic potential of a tumour cell depends on multiple, reciprocal interactions between the primary tumour and distant sites. These interactions determine tumour progression. Studies of metastasis have allowed us to develop treatments that focus on therapeutic effectiveness. These new treatments account for the frequent metastasis of some tumours to target organs such as bones, lungs, brain, and liver. The purpose of this review is first to describe interactions between the cellular and molecular entities and the target organ tumour environment that enables metastasis. A second aim is to describe the complex mechanisms that mediate these interactions.

High mucin-7 expression is an independent predictor of adverse clinical outcomes in patients with clear-cell renal cell carcinoma

Mucin-7 is a member of the secreted mucins family. Mucins might play a crucial role during tumor development and its aberrant expression was observed in several types of tumor. Our study aims to evaluate the prognostic significance of Mucin-7 expression in postoperative clear-cell renal cell carcinoma (ccRCC) patients. In this retrospective study, we enrolled 392 patients with ccRCC undergoing nephrectomy between 2008 and 2009 in a single center. The median follow-up was 73 months (range 39-74 months). Mucin-7 expression was evaluated by immunohistochemistry protocol on ccRCC specimens. Kaplan-Meier survival analysis was conducted to compare survival curves. Univariate and multivariate Cox regression models were applied to assess the impact of prognostic factors in overall survival (OS) and recurrence-free survival (RFS). A nomogram was then constructed based on the independent prognosticators identified on multivariate analysis. The results displayed that Mucin-7 expression was significantly associated with tumor size (p = 0.034), pT stage (p = 0.004), TNM stage (p = 0.008), and necrosis (p = 0.043). Patients with high Mucin-7 expression had significant worse outcomes in both OS (p < 0.001) and RFS (p < 0.001) compared to those with low Mucin-7 expression. MUC7 expression was considered as an independent predictive factor for OS (HR 2.286; 95 %CI 1.167-4.475; p = 0.016) and RFS (HR 2.055; 95 %CI 1.086-3.887; p = 0.027). A nomogram integrating Mucin-7 expression and other independent prognosticators was constructed. In summary, the high Mucin-7 expression is a potential prognosticator of adverse clinical outcome in ccRCC patients after surgery.

Platelet integrin 61 controls lung metastasis through direct binding to cancer cell-derived ADAM9

Metastatic dissemination of cancer cells, which accounts for 90% of cancer mortality, is the ultimate hallmark of malignancy. Growing evidence suggests that blood platelets have a predominant role in tumor metastasis; however, the molecular mechanisms involved remain elusive. Here, we demonstrate that genetic deficiency of integrin α6β1 on platelets markedly decreases experimental and spontaneous lung metastasis. In vitro and in vivo assays reveal that human and mouse platelet α6β1 supports platelet adhesion to various types of cancer cells. Using a knockdown approach, we identified ADAM9 as the major counter receptor of α6β1 on both human and mouse tumor cells. Static and flow-based adhesion assays of platelets binding to DC-9, a recombinant protein covering the disintegrin-cysteine domain of ADAM9, demonstrated that this receptor directly binds to platelet α6β1. In vivo studies showed that the interplay between platelet α6β1 and tumor cell-expressed ADAM9 promotes efficient lung metastasis. The integrin α6β1-dependent platelet-tumor cell interaction induces platelet activation and favors the extravasation process of tumor cells. Finally, we demonstrate that a pharmacological approach targeting α6β1 efficiently impairs tumor metastasis through a platelet-dependent mechanism. Our study reveals a mechanism by which platelets promote tumor metastasis and suggests that integrin α6β1 represents a promising target for antimetastatic therapies.

Platelets are versatile cells: New discoveries in hemostasis, thrombosis, immune responses, tumor metastasis and beyond

Platelets are small anucleate blood cells generated from megakaryocytes in the bone marrow and cleared in the reticuloendothelial system. At the site of vascular injury, platelet adhesion, activation and aggregation constitute the first wave of hemostasis. Blood coagulation, which is initiated by the intrinsic or extrinsic coagulation cascades, is the second wave of hemostasis. Activated platelets can also provide negatively-charged surfaces that harbor coagulation factors and markedly potentiate cell-based thrombin generation. Recently, deposition of plasma fibronectin, and likely other plasma proteins, onto the injured vessel wall has been identified as a new "protein wave of hemostasis" that may occur even earlier than the first wave of hemostasis, platelet accumulation. Although no experimental evidence currently exists, it is conceivable that platelets may also contribute to this protein wave of hemostasis by releasing their granule fibronectin and other proteins that may facilitate fibronectin self- and non-self-assembly on the vessel wall. Thus, platelets may contribute to all three waves of hemostasis and are central players in this critical physiological process to prevent bleeding. Low platelet counts in blood caused by enhanced platelet clearance and/or impaired platelet production are usually associated with hemorrhage. Auto- and allo-immune thrombocytopenias such as idiopathic thrombocytopenic purpura and fetal and neonatal alloimmune thrombocytopenia may cause life-threatening bleeding such as intracranial hemorrhage. When triggered under pathological conditions such as rupture of an atherosclerotic plaque, excessive platelet activation and aggregation may result in thrombosis and vessel occlusion. This may lead to myocardial infarction or ischemic stroke, the major causes of mortality and morbidity worldwide. Platelets are also involved in deep vein thrombosis and thromboembolism, another leading cause of mortality. Although fibrinogen has been documented for more than half a century as essential for platelet aggregation, recent studies demonstrated that fibrinogen-independent platelet aggregation occurs in both gene deficient animals and human patients under physiological and pathological conditions (non-anti-coagulated blood). This indicates that other unidentified platelet ligands may play important roles in thrombosis and might be novel antithrombotic targets. In addition to their critical roles in hemostasis and thrombosis, emerging evidence indicates that platelets are versatile cells involved in many other pathophysiological processes such as innate and adaptive immune responses, atherosclerosis, angiogenesis, lymphatic vessel development, liver regeneration and tumor metastasis. This review summarizes the current knowledge of platelet biology, highlights recent advances in the understanding of platelet production and clearance, molecular and cellular events of thrombosis and hemostasis, and introduces the emerging roles of platelets in the immune system, vascular biology and tumorigenesis. The clinical implications of these basic science and translational research findings will also be discussed.

Effects of shear on P-selectin deposition in microfluidic channels

Traditional leukocyte adhesion assays have provided significant insight into the mechanisms of leukocyte rolling in part through the use of homogeneously coated surfaces. These assays typically involve protein coating of glass coverslips or plastic petri dishes applied via a static drop of protein solution. With this approach, it is difficult to spatially control the location of proteins to fabricate surface-bound protein gradients that mimic in vivo situations. Microfluidic patterning of proteins with microfluidic devices has become a popular technique due to the ability to spatially pattern proteins on a cellular scale. Despite the advantages of microfluidic patterning, few studies have systematically investigated the effects of perfusion time, protein concentration, and perfusion shear stress on protein deposition. Herein, we demonstrated the fabrication of both line and step gradients of P-selectin on glass substrates that support cell rolling and adhesion assays. Investigation of the flow conditions during the microfluidic patterning led to several significant findings. We observed that the protein deposition time of 5 min was sufficient to deposit adequate P-selectin to support neutrophil rolling. We demonstrated that the amount of membrane P-selectin (mP-selectin) or recombinant P-selectin (rP-selectin) deposited showed a dependence on the perfusion shear stress between 4.0 and 32.0 dyn/cm(2), while similar studies with fibronectin or fibrinogen showed no shear stress dependence. Finally, we also created step changes in surface adherent protein concentration of P-selectin to characterize leukocyte-rolling behavior in response to sudden changes in ligand density.

Cancer-Associated Thrombosis: Regulatory Mechanisms and Emerging Directions

Venous thrombosis is a common complication in cancer patients, and some cancer chemotherapies are associated with an increased risk of venous thromboembolism. The regulatory mechanisms that control thrombus formation and subsequent resolution in patients with cancer, however, are incompletely understood, and novel treatments for cancer-associated thrombosis may arise from a better understanding of such mechanisms. In this chapter, pathways that regulate cancer-associated thrombus formation are outlined, and the effects of anti-angiogenic cancer chemotherapies on venous thrombus resolution are highlighted. Potentially pro-thrombotic effects of anti-angiogenic agents are important considerations when managing the complications of venous thrombosis in cancer patients.

Interaction between circulating cancer cells and platelets: clinical implication

Metastasis is the main cause of cancer-associated mortality. During this complicated process, some cancer cells, also called circulating tumor cells (CTCs), detach from primary sites, enter bloodstream and extravasate at metastatic site. Thrombocytosis is frequently observed in patients with metastatic cancers suggesting the important role of platelets in metastasis. Therefore this review focuses on how platelets facilitate the generation of CTCs, protect them from various host attacks, such as immune assaults, apoptosis and shear stress, and regulate CTCs intravasation/extravasation. Platelet-derived cytokines and receptors are involved in this cascade. Identification the mechanisms underlie platelet-CTCs interactions could lead to the development of new platelet-targeted therapeutic strategy to reduce metastasis.

Pathobiological implications of mucin glycans in cancer: Sweet poison and novel targets

Mucins are large glycoproteins expressed on the epithelia that provide a protective barrier against harsh insults from toxins and pathogenic microbes. These glycoproteins are classified primarily as being secreted and membrane-bound; both forms are involved in pathophysiological functions including inflammation and cancer. The high molecular weight of mucins is attributed to their large polypeptide backbone that is extensively covered by glycan moieties that modulate the function of mucins and, hence, play an important role in physiological functions. Deregulation of glycosylation machinery during malignant transformation results in altered mucin glycosylation. This review describes the functional implications and pathobiological significance of altered mucin glycosylation in cancer. Further, this review delineates various factors such as glycosyltransferases and tumor microenvironment that contribute to dysregulation of mucin glycosylation during cancer. Finally, this review discusses the scope of mucin glycan epitopes as potential diagnostic and therapeutic targets.

Spatiotemporal Targeting of a Dual-Ligand Nanoparticle to Cancer Metastasis

Various targeting strategies and ligands have been employed to direct nanoparticles to tumors that upregulate specific cell-surface molecules. However, tumors display a dynamic, heterogeneous microenvironment, which undergoes spatiotemporal changes including the expression of targetable cell-surface biomarkers. Here, we investigated a dual-ligand nanoparticle to effectively target two receptors overexpressed in aggressive tumors. By using two different chemical specificities, the dual-ligand strategy considered the spatiotemporal alterations in the expression patterns of the receptors in cancer sites. As a case study, we used two mouse models of metastasis of triple-negative breast cancer using the MDA-MB-231 and 4T1 cells. The dual-ligand system utilized two peptides targeting P-selectin and αvβ3 integrin, which are functionally linked to different stages of the development of metastatic disease at a distal site. Using in vivo multimodal imaging and post mortem histological analyses, this study shows that the dual-ligand nanoparticle effectively targeted metastatic disease that was otherwise missed by single-ligand strategies. The dual-ligand nanoparticle was capable of capturing different metastatic sites within the same animal that overexpressed either receptor or both of them. Furthermore, the highly efficient targeting resulted in 22% of the injected dual-ligand nanoparticles being deposited in early-stage metastases within 2 h after injection.

Vascular Targeting of a Gold Nanoparticle to Breast Cancer Metastasis

The vast majority of breast cancer deaths are due to metastatic disease. Although deep tissue targeting of nanoparticles is suitable for some primary tumors, vascular targeting may be a more attractive strategy for micrometastasis. This study combined a vascular targeting strategy with the enhanced targeting capabilities of a nanoparticle to evaluate the ability of a gold nanoparticle (AuNP) to specifically target the early spread of metastatic disease. As a ligand for the vascular targeting strategy, we utilized a peptide targeting alpha(v) beta(3) integrin, which is functionally linked to the development of micrometastases at a distal site. By employing a straightforward radiolabeling method to incorporate Technetium-99m into the AuNPs, we used the high sensitivity of radionuclide imaging to monitor the longitudinal accumulation of the nanoparticles in metastatic sites. Animal and histological studies showed that vascular targeting of the nanoparticle facilitated highly accurate targeting of micrometastasis in the 4T1 mouse model of breast cancer metastasis using radionuclide imaging and a low dose of the nanoparticle. Because of the efficient targeting scheme, 14% of the injected AuNP deposited at metastatic sites in the lungs within 60 min after injection, indicating that the vascular bed of metastasis is a viable target site for nanoparticles.

Glycosyltransferases involved in the synthesis of MUC-associated metastasis-promoting selectin ligands

The sialyl Lewis a and x (sLe(a/x)) antigens frequently displayed on the surface of tumor cells are involved in metastasis. Their synthesis has been attributed to altered expression of selective glycosyltransferases. Identification of these glycosyltransferases and the glycoproteins that carry these carbohydrate antigens should help advance our understanding of selectin-mediated cancer metastasis. In this study, quantitative real-time polymerase chain reaction analysis coupled with in situ proximity ligation assay and small interference RNA treatment shows involvement of β3galactosyltransferase-V in the synthesis of MUC16-associated sLe(a) in H292 cells. Also, α3fucosyltransferase-V, which is absent in BEAS-2B human immortalized bronchial epithelial cells and A549 lung carcinoma cells, participates in the synthesis of MUC1-associated sLe(x) in CFT1 human immortalized bronchial epithelial cells and H292 lung carcinoma cells. Neither selectin ligand is found on MUC1 in BEAS-2B and A549 cells. Knockdown of either enzyme suppresses migration, and selectin tethering and rolling properties of H292 cells under dynamic flow as determined by wound healing and parallel plate flow chamber assays, respectively. These results provide insights into how the synthesis of mucin-associated selectin ligands and the metastatic properties of cancer cells can be regulated by selective glycosyltransferases that work on mucins. They may help develop novel anticancer drugs.

Altered tumor-cell glycosylation promotes metastasis

Malignant transformation of cells is associated with aberrant glycosylation presented on the cell-surface. Commonly observed changes in glycan structures during malignancy encompass aberrant expression and glycosylation of mucins; abnormal branching of N-glycans; and increased presence of sialic acid on proteins and glycolipids. Accumulating evidence supports the notion that the presence of certain glycan structures correlates with cancer progression by affecting tumor-cell invasiveness, ability to disseminate through the blood circulation and to metastasize in distant organs. During metastasis tumor-cell-derived glycans enable binding to cells in their microenvironment including endothelium and blood constituents through glycan-binding receptors – lectins. In this review, we will discuss current concepts how tumor-cell-derived glycans contribute to metastasis with the focus on three types of lectins: siglecs, galectins, and selectins. Siglecs are present on virtually all hematopoietic cells and usually negatively regulate immune responses. Galectins are mostly expressed by tumor cells and support tumor-cell survival. Selectins are vascular adhesion receptors that promote tumor-cell dissemination. All lectins facilitate interactions within the tumor microenvironment and thereby promote cancer progression. The identification of mechanisms how tumor glycans contribute to metastasis may help to improve diagnosis, prognosis, and aid to develop clinical strategies to prevent metastasis.

Lipopolysaccharide induces the interactions of breast cancer and endothelial cells via activated monocytes

The adhesion of circulating cancer cells to vascular endothelium is a key step in hematogenous metastasis. Cancer cell-endothelium interactions are mediated by cell adhesion molecules that can also be involved in the arrest of monocytes and other circulating leukocytes on endothelium in inflammation. Static and microfluidic flow adhesion assays as well as flow cytometry were conducted in this study to elucidate the role of monocytes, bacterial lipopolysaccharide (LPS), and histamine in breast cancer cell adhesion to vascular endothelial cells. Tumor necrosis factor-α (TNF-α) released from LPS-treated monocytes triggered the expression of intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells. Histamine augmented the TNF-α effect, leading to a high number of arrested breast cancer cells under both static and shear flow conditions. LPS-treated monocytes were shown to enhance the arrest of breast cancer cells by anchoring the cancer cells to activated endothelial cells. This anchorage was achieved by binding cancer cell ICAM-1 to monocyte β2 integrins and binding endothelial ICAM-1 and VCAM-1 to monocyte β1 and β2 integrins. The results of this study imply that LPS is an important risk factor for cancer metastasis and that the elevated serum level of histamine further increases the risk of LPS-induced cancer metastasis. Preventing bacterial infections is essential in cancer treatment, and it is particularly vital for cancer patients affected by allergy.

Metastatic growth progression caused by PSGL-1-mediated recruitment of monocytes to metastatic sites

Tumor cell-derived selectin ligands mediate contact to the endothelium, platelets, and leukocytes through binding to selectins that facilitates metastasis. Here, we describe the mechanism of how endogenous (non-tumor derived) selectin ligands contribute to metastasis using α(1,3)fucosyltransferase 7 (Fuc-TVII(-/-))-deficient mice. Experimental metastasis of MC-38GFP and Lewis lung (3LL) carcinoma cells was attenuated in Fuc-TVII(-/-) mice, which express minimal amount of selectin ligands. We show that metastasis is dependent on selectin ligands carried on hematopoietic cells. P-selectin glycoprotein ligand-1 (PSGL-1) was identified as the major ligand facilitating monocyte accumulation at metastatic sites. Reduced recruitment of monocytes to metastasizing tumor cells in Fuc-TVII(-/-) mice correlated with attenuated metastasis. Adoptive transfer of Fuc-T7(+) monocytes rescued metastasis in Fuc-TVII(-/-) mice, indicating that selectin ligand-dependent recruitment of monocytes is required for cancer progression. Cytokine analysis in metastatic lungs revealed high expression of CCL2 in C57BL/6 mice that was significantly lower in Fuc-TVII(-/-) mice. The absence of monocyte recruitment in Fuc-TVII(-/-) mice correlated with increased apoptosis of tumor cells. Thus, the recruitment of monocytes to metastasizing tumor cells is facilitated by endogenous selectin ligands on monocytes that enable efficient tumor cell survival, extravasation, and metastasis.

PDGFRB promotes liver metastasis formation of mesenchymal-like colorectal tumor cells

In epithelial tumors, the platelet-derived growth factor receptor B (PDGFRB) is mainly expressed by stromal cells of mesenchymal origin. Tumor cells may also acquire PDGFRB expression following epithelial-to-mesenchymal transition (EMT), which occurs during metastasis formation. Little is known about PDGFRB signaling in colorectal tumor cells. We studied the relationship between PDGFRB expression, EMT, and metastasis in human colorectal cancer (CRC) cohorts by analysis of gene expression profiles. PDGFRB expression in primary CRC was correlated with short disease-free and overall survival. PDGFRB was co-expressed with genes involved in platelet activation, transforming growth factor beta (TGFB) signaling, and EMT in three CRC cohorts. PDGFRB was expressed in mesenchymal-like tumor cell lines in vitro and stimulated invasion and liver metastasis formation in mice. Platelets, a major source of PDGF, preferentially bound to tumor cells in a non-activated state. Platelet activation caused robust PDGFRB tyrosine phosphorylation on tumor cells in vitro and in liver sinusoids in vivo. Platelets also release TGFB, which is a potent inducer of EMT. Inhibition of TGFB signaling in tumor cells caused partial reversion of the mesenchymal phenotype and strongly reduced PDGFRB expression and PDGF-stimulated tumor cell invasion. These results suggest that PDGFRB may contribute to the aggressive phenotype of colorectal tumors with mesenchymal properties, most likely downstream of platelet activation and TGFB signaling.