Podoplanin promotes tumor growth, platelet aggregation, and venous thrombosis in murine models of ovarian cancer

Therapeutic Apheresis Using a β2-Microglobulin Removal Column Reduces Circulating Tumor Cell Count

An elevated serum β2-microglobulin (β2M) level is indicative of impaired glomerular filtration and prerenal diseases, such as malignant tumors, autoimmune disorders, and liver diseases. An elevated serum β2M level has been shown to promote metastasis via the induction of epithelial-mesenchymal transition (EMT) in cancer cells. However, the therapeutic potential of targeting β2M remains unclear. Here, we aimed to investigate the efficacy of Filtor, a small polymethyl methacrylate fiber-based β2M removal column, in reducing the β2M level and suppressing cancer cell-induced EMT and metastasis. We assessed the effects of Filtor on the changes in metastasis based on the number of circulating tumor cells (CTCs), which reflects the post-EMT cancer cell population. We performed therapeutic apheresis using Filtor on a male patient with sinonasal neuroendocrine carcinoma, a female patient with a history of colorectal cancer, and another female patient with a history of pancreatic ductal adenocarcinoma. Significantly low serum β2M levels and CTC counts were observed immediately and 4 weeks after treatment compared with those in the pretreatment phase. Moreover, the CTC count immediately after therapeutic intervention was markedly reduced, likely because Filtor had trapped CTCs directly. These findings suggest that therapeutic apheresis with Filtor can prevent cancer metastasis and recurrence by directly removing CTCs.

Endothelial CLEC-1b plays a protective role against cancer hematogenous metastasis

Metastasis, which is the spread of cancer cells into distant organs, is a critical determinant of prognosis in patients with cancer, and blood vessels are the major route for cancer cells to spread systemically. Extravasation is a critical process for the hematogenous metastasis; however, its underlying molecular mechanisms remain poorly understood. Here, we identified that senescent ECs highly express C-type lectin domain family 1 member B (CLEC-1b), and that endothelial CLEC-1b inhibits the hematogenous metastasis of a certain type of cancer. CLEC-1b expression was enhanced in ECs isolated from aged mice, senescent cultured human ECs, and ECs of aged human. CLEC-1b overexpression in ECs prevented the disruption of endothelial integrity, and inhibited the transendothelial migration of cancer cells expressing podoplanin (PDPN), a ligand for CLEC-1b. Notably, target activation of CLEC-1b in ECs decreased the hematogenous metastasis in the lungs by cancer cells expressing PDPN in mice. Our data reveal the protective role of endothelial CLEC-1b against cancer hematogenous metastasis. Considering the high CLEC-1b expression in senescent ECs, EC senescence may play a beneficial role with respect to the cancer hematogenous metastasis.

The role of platelets in central hubs of inflammation: A literature review

Platelets are increasingly recognized for their multifaceted roles in inflammation beyond their traditional involvement in haemostasis. This review consolidates knowledge on platelets as critical players in inflammatory responses. This study did an extensive search of electronic databases and identified studies on platelets in inflammation, focusing on molecular mechanisms, cell interactions, and clinical implications, emphasizing recent publications. Platelets contribute to inflammation via surface receptors, release of mediators, and participation in neutrophil extracellular trap formation. They are implicated in diseases like atherosclerosis, rheumatoid arthritis, and sepsis, highlighting their interaction with immune cells as pivotal in the onset and resolution of inflammation. Platelets are central to regulating inflammation, offering new therapeutic targets for inflammatory diseases. Future research should explore specific molecular pathways of platelets in inflammation for therapeutic intervention.

Research progress on venous thrombosis development in patients with malignant tumors

The coexistence of venous thromboembolism (VTE) within patients with cancer, known as cancer-associated thrombosis (CAT), stands as a prominent cause of mortality in this population. Over recent years, the incidence of VTE has demonstrated a steady increase across diverse tumor types, influenced by several factors such as patient management, tumor-specific risks, and treatment-related aspects. Furthermore, mutations in specific genes have been identified as potential contributors to increased CAT occurrence in particular cancer subtypes. We conducted an extensive review encompassing pivotal historical and ongoing studies on CAT. This review elucidates the risks, mechanisms, reliable markers, and risk assessment methodologies that can significantly guide effective interventions in clinical practice.

Inhibiting MMP13 Attenuates Deep Vein Thrombosis in a Mouse Model by Reducing the Expression of Pdpn

OBJECTIVE

Matrix metalloproteinase 13 (MMP13) is an extracellular matrix protease that affects the progression of atherosclerotic plaques and arterial thrombi by degrading collagens, modifying protein structures and regulating inflammatory responses, but its role in deep vein thrombosis (DVT) has not been determined. The purpose of this study was to investigate the potential effects of MMP13 and MMP13-related genes on the formation of DVT.

METHODS

We altered the expression level of MMP13 in vivo and conducted a transcriptome study to examine the expression and relationship between MMP13 and MMP13-related genes in a mouse model of DVT. After screening genes possibly related to MMP13 in DVT mice, the expression levels of candidate genes in human umbilical vein endothelial cells (HUVECs) and the venous wall were evaluated. The effect of MMP13 on platelet aggregation in HUVECs was investigated in vitro.

RESULTS

Among the differentially expressed genes, interleukin 1 beta, podoplanin (Pdpn), and factor VIII von Willebrand factor (F8VWF) were selected for analysis in mice. When MMP13 was inhibited, the expression level of PDPN decreased significantly in vitro. In HUVECs, overexpression of MMP13 led to an increase in the expression level of PDPN and induced platelet aggregation, while transfection of PDPN-siRNA weakened the ability of MMP13 to increase platelet aggregation.

CONCLUSIONS

Inhibiting the expression of MMP13 could reduce the burden of DVT in mice. The mechanism involves downregulating the expression of Pdpn through MMP13, which could provide a novel gene target for DVT diagnosis and treatment.

C-type lectin-like receptor 2: roles and drug target

C-type lectin-like receptor-2 (CLEC-2) is a member of the C-type lectin superfamily of cell surface receptors. The first confirmed endogenous and exogenous ligands of CLEC-2 are podoplanin and rhodocytin, respectively. CLEC-2 is expressed on the surface of platelets, which participates in platelet activation and aggregation by binding with its ligands. CLEC-2 and its ligands are involved in pathophysiological processes, such as atherosclerosis, cancer, inflammatory thrombus status, maintenance of vascular wall integrity, and cancer-related thrombosis. In the last 5 years, different anti- podoplanin antibody types have been developed for the treatment of cancers, such as glioblastoma and lung cancer. New tests and new diagnostics targeting CLEC-2 are also discussed. CLEC-2 mediates thrombosis in various pathological states, but CLEC-2-specific deletion does not affect normal hemostasis, which would provide a new therapeutic tool for many thromboembolic diseases. The CLEC-2-podoplanin interaction is a target for cancer treatment. CLEC-2 may be applied in clinical practice and play a therapeutic role.

Exosome-transmitted podoplanin promotes tumor-associated macrophage-mediated immune tolerance in glioblastoma

AIMS

Glioblastoma is the most frequent and aggressive primary brain tumor, characterized by rapid disease course and poor treatment responsiveness. The abundance of immunosuppressive macrophages in glioblastoma challenges the efficacy of novel immunotherapy.

METHODS

Bulk RNA-seq and single-cell RNA-seq of glioma patients from public databases were comprehensively analyzed to illustrate macrophage infiltration patterns and molecular characteristics of podoplanin (PDPN). Multiplexed fluorescence immunohistochemistry staining of PDPN, GFAP, CD68, and CD163 were performed in glioma tissue microarray. The impact of PDPN on macrophage immunosuppressive polarization was investigated using a co-culture system. Bone marrow-derived macrophages (BMDMs) and OT-II T cells isolated from BALB/c and OT-II mice respectively were co-cultured to determine T-cell adherence. Pathway alterations were probed through RNA sequencing and western blot analyses.

RESULTS

Our findings demonstrated that PDPN is notably correlated with the expression of CD68 and CD163 in glioma tissues. Additionally, macrophages phagocytosing PDPN-containing EVs (EVsPDPN ) from GBM cells presented increased CD163 expression and augmented secretion of immunoregulatory cytokine (IL-6, IL-10, TNF-α, and TGF-β1). PDPN within EVs was also associated with enhanced phagocytic activity and reduced MHC II expression in macrophages, compromising CD4+ T-cell activation.

CONCLUSIONS

This investigation underscores that EVsPDPN derived from glioblastoma cells contributes to M2 macrophage-mediated immunosuppression and is a potential prognostic marker and therapeutic target in glioblastoma.

The dynamic role of platelets in cancer progression and their therapeutic implications

Systemic antiplatelet treatment represents a promising option to improve the therapeutic outcomes and therapeutic efficacy of chemotherapy and immunotherapy due to the critical contribution of platelets to tumour progression. However, until recently, targeting platelets as a cancer therapeutic has been hampered by the elevated risk of haemorrhagic and thrombocytopenic (low platelet count) complications owing to the lack of specificity for tumour-associated platelets. Recent work has advanced our understanding of the molecular mechanisms responsible for the contribution of platelets to tumour progression and metastasis. This has led to the identification of the biological changes in platelets in the presence of tumours, the complex interactions between platelets and tumour cells during tumour progression, and the effects of platelets on antitumour therapeutic response. In this Review, we present a detailed picture of the dynamic roles of platelets in tumour development and progression as well as their use in diagnosis, prognosis and monitoring response to therapy. We also provide our view on how to overcome challenges faced by the development of precise antiplatelet strategies for safe and efficient clinical cancer therapy.

Cancer-associated fibroblasts promote venous thrombosis through podoplanin/CLEC-2 interaction in podoplanin-negative lung cancer mouse model

BACKGROUND

Cancer-associated thrombosis (CAT) is the leading cause of morbidity and mortality. Cancer-associated fibroblasts (CAFs) are a prominent component of the tumor microenvironment that contributes to cancer progression through direct cell-cell interactions and the release of extracellular vesicles (EVs). However, the role of CAFs in CAT remains unclear.

OBJECTIVE

This study aims to investigate whether CAFs aggravate CAT and the underlying molecular mechanism using a preclinical mouse lung cancer model.

METHODS

We designed a Lewis lung carcinoma (LLC) tumor-bearing mouse model. CAFs were characterized using fluorescence immunohistostaining. The presence of podoplanin, a platelet-activating membrane protein through C-type lectin-like receptor 2 (CLEC-2), in EVs isolated from primary CAFs or LLC tumor tissues was assessed by immunoblotting. The platelet activation and aggregation abilities of the EVs were quantified using flow cytometry. Podoplanin plasma levels were measured by enzyme-linked immunosorbent assay. Venous thrombosis was induced in the femoral vein using 2.5% ferric chloride. The anti-CLEC-2 monoclonal antibody 2A2B10 was used to deplete CLEC-2 on the surface of the platelets.

RESULTS

CAFs expressing CD90, PDGFRβ, HSP47, CD34, and vimentin, co-expressed podoplanin and induced platelet activation and aggregation in a CLEC-2-dependent manner. Tumor-bearing mice showed elevated podoplanin plasma levels. CAF-EV injection and tumor-bearing mice showed shorter occlusion time in the venous thrombosis model. Although tumor growth was not altered, antibody-induced CLEC-2 depletion suppressed venous thrombosis in the tumor-bearing state but not in the healthy condition.

CONCLUSION

CAFs and CAF-derived EVs induce CLEC-2-dependent platelet aggregation and aggravate venous thrombosis.

Cell Membrane Sialome: Sialic Acids as Therapeutic Targets and Regulators of Drug Resistance in Human Cancer Management

A cellular sialome is a physiologically active and dynamically changing component of the cell membrane. Sialylation plays a crucial role in tumor progression, and alterations in cellular sialylation patterns have been described as modulators of chemotherapy effectiveness. However, the precise mechanisms through which altered sialylation contributes to drug resistance in cancer are not yet fully understood. This review focuses on the intricate interplay between sialylation and cancer treatment. It presents the role of sialic acids in modulating cell-cell interactions, the extracellular matrix (ECM), and the immunosuppressive processes within the context of cancer. The issue of drug resistance is also discussed, and the mechanisms that involve transporters, the tumor microenvironment, and metabolism are analyzed. The review explores drugs and therapeutic approaches that may induce modifications in sialylation processes with a primary focus on their impact on sialyltransferases or sialidases. Despite advancements in cellular glycobiology and glycoengineering, an interdisciplinary effort is required to decipher and comprehend the biological characteristics and consequences of altered sialylation. Additionally, understanding the modulatory role of sialoglycans in drug sensitivity is crucial to applying this knowledge in clinical practice for the benefit of cancer patients.

A MALDI Mass Spectrometry Imaging Sample Preparation Method for Venous Thrombosis with Initial Lipid Characterization of Lab-Made and Murine Clots

Venous thromboembolism (VTE) and its complications affect over 900,000 people in the U.S. annually, with a third of cases resulting in fatality. Despite such a high incidence rate, venous thrombosis research has not led to significant changes in clinical treatments, with standard anti-coagulant therapy (heparin followed by a vitamin K antagonist) being used since the 1950s. Mechanical thrombectomy is an alternative strategy for treating venous thrombosis; however, clinical guidelines for patient selection have not been well-established or accepted. The effectiveness of both treatments is impacted by the heterogeneity of the thrombus, including the mechanical properties of its cellular components and its molecular makeup. A full understanding of the complex interplay between disease initiation and progression, biochemical molecular changes, tissue function, and mechanical properties calls for a multiplex and multiscale approach. In this work, we establish a protocol for using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging to characterize spatial heterogeneity of biomolecules in lab-made blood clots and ex vivo murine thrombi. In this work, we compared (1) tissue preservation and cryosectioning methods, (2) various matrixes, 9-aminoacridine hydrochloride monohydrate (9AA), 2,5-dihydroxybenzoic acid (DHB), and alpha-cyano-4-hydroxycinnamic acid matrix (CHCA), (3) plasma-rich versus red-blood-cell rich lab-made blood clots, and (4) lab-made blood clots versus ex vivo murine thrombi. This project is the first step in our work to combine mass spectrometry imaging with biomechanical testing of blood clots to improve our understanding of VTE.

Identification and validation of an ECM organization-related gene signature as a prognostic biomarker and therapeutic target for glioma patients

BACKGROUND

Glioma is the most common and devastating form of malignant brain tumor, with a poor prognosis. Extracellular matrix (ECM) organization is a crucial determinant of glioma invasion and progression. However, the clinical significance of ECM organization in glioma patients remains unclear.

OBJECTIVE

To evaluate the prognostic value of ECM organization-related genes in glioma patients and identify potential therapeutic targets.

METHODS

Bulk RNA-sequencing and corresponding clinical data for patients with glioma were downloaded from TCGA and GEO databases. Differentially expressed ECM organization genes were identified, and an ECM organization-related gene prognostic model was then generated. Furthermore, the prognostic model has validated in the Chinese Glioma Genome Atlas (CGGA) dataset. The role of TIMP1 in glioma cells by using various functional assays revealed their underlying mechanism in vitro.

RESULTS

We identified and validated a nine-gene signature (TIMP1, SERPINE1, PTX3, POSTN, PLOD3, PDPN, LOXL1, ITGA2, and COL8A1) related to ECM organization as a robust prognostic biomarker for glioma. Time-dependent ROC curve analysis confirmed the specificity and sensitivity of the signature. The signature was closely related to an immunosuppressive phenotype, and its combination with immune checkpoints served as a good predictor for patients' clinical outcomes. Notably, single-cell RNA sequencing analysis revealed high expression of TIMP1 in astrocytes and oligodendrocyte progenitor cells in glioma patients. Last, we show that TIMP1 regulates glioma cell growth and invasion via the AKT/GSK3β signaling pathway.

CONCLUSION

This study provides promising insights into predicting glioma prognosis and identifying a potential therapeutic target in TIMP1.

Tumor Cells Transmit Drug Resistance via Cisplatin-Induced Extracellular Vesicles

Cisplatin is a first-line clinical agent used for treating solid tumors. Cisplatin damages the DNA of tumor cells and induces the production of high levels of reactive oxygen species to achieve tumor killing. Tumor cells have evolved several ways to tolerate this damage. Extracellular vesicles (EVs) are an important mode of information transfer in tumor cells. EVs can be substantially activated under cisplatin treatment and mediate different responses of tumor cells under cisplatin treatment depending on their different cargoes. However, the mechanism of action of tumor-cell-derived EVs under cisplatin treatment and their potential cargoes are still unclear. This review considers recent advances in cisplatin-induced release of EVs from tumor cells, with the expectation of providing a new understanding of the mechanisms of cisplatin treatment and drug resistance, as well as strategies for the combined use of cisplatin and other drugs.

Podoplanin and CLEC-2 levels in patients with COVID-19

Introduction

Podoplanin (PDPN gene) and CLEC-2 are involved in inflammatory hemostasis and have also been related with the pathogenesis of thrombosis. Emerging evidence also suggest that podoplanin can exert protective effects in sepsis and in acute lung injury. In lungs, podoplanin is co-expressed with ACE2, which is the main entry receptor for SARS-CoV-2.

Aim

To explore the role of podoplanin and CLEC-2 in COVID-19.

Methods

Circulating levels of podoplanin and CLEC-2 were measured in 30 consecutive COVID-19 patients admitted due to hypoxia, and in 30 age- and sex-matched healthy individuals. Podoplanin expression in lungs from patients who died of COVID-19 was obtained from two independent public databases of single-cell RNAseq from which data from control lungs were also available.

Results

Circulating podoplanin levels were lower in COVID-19, while no difference was observed in CLEC-2 levels. Podoplanin levels were significantly inversely correlated with markers of coagulation, fibrinolysis and innate immunity. scRNAseq data confirmed that PDPN is co-expressed with ACE2 in pneumocytes, and showed that PDPN expression is lower in this cell compartment in lungs from patients with COVID-19.

Conclusion

Circulating levels of podoplanin are lower in COVID-19, and the magnitude of this reduction is correlated with hemostasis activation. We also demonstrate the downregulation of PDPN at the transcription level in pneumocytes. Together, our exploratory study questions whether an acquired podoplanin deficiency could be involved in the pathogenesis of acute lung injury in COVID-19, and warrant additional studies to confirm and refine these findings.

Podoplanin promotes the carcinogenicity of gastric cancer by activating ezrin and mediating the crosstalk between tumour cells and cancer-associated fibroblasts

NEW FINDINGS

What is the central question of this study? To reveal the role and biological mechanism of PDPN in the progression of gastric cancer. What is the main finding and its importance? This study focused on a prognostic predictor, PDPN, which acted as a promoter in the progression of gastric cancer through the activation of Ezrin expression and CAFs. This finding may expand a new route for the gene-targeted therapy in gastric cancer.

ABSTRACT

Gastric cancer (GC) is a frequent malignant disease and the main cause of cancer-related death in the world. Podoplanin (PDPN) has been proved to be involved in the progression of various cancers. However, the role and biological mechanism of PDPN in GC are still vague. In our study, we detected the expression of PDPN in GC tissues and cell lines using RT-qPCR, western blot and datasets. The overall survival of GC patients was analysed with a Kaplan-Meier plot. The effects of PDPN overexpression and silencing on GC cell progression were assessed by Cell Counting Kit-8, flow cytometry and a wound healing assay. Besides, the modulation of PDPN on ezrin activation was investigated. We further explored the role of PDPN in the crosstalk between GC cells and cancer associated fibroblasts (CAFs). Results showed that PDPN was upregulated in GC tissues and cell lines. High expression of PDPN was correlated with poor prognosis of GC patients. PDPN positively regulated the viability, migration and invasion, but inhibited apoptosis, of GC cells by mediating the activation of ezrin. Meanwhile, the change in PDPN in GC cells activated CAFs and promoted the production of cytokines secreted by CAFs, which induced the progression of GC cells. These findings may provide a novel target for GC therapy.

Podoplanin: A potential therapeutic target for thrombotic diseases

As a specific lymphatic marker and a key ligand of C-type lectin-like receptor 2 (CLEC-2), podoplanin (Pdpn) is involved in various physiological and pathological processes such as growth and development, respiration, blood coagulation, lymphangiogenesis, angiogenesis, and inflammation. Thrombotic diseases constitute a major cause of disability and mortality in adults, in which thrombosis and inflammation play a crucial role. Recently, increasing evidence demonstrates the distribution and function of this glycoprotein in thrombotic diseases such as atherosclerosis, ischemic stroke, venous thrombosis, ischemic-reperfusion injury (IRI) of kidney and liver, and myocardial infarction. Evidence showed that after ischemia, Pdpn can be acquired over time by a heterogeneous cell population, which may not express Pdpn in normal conditions. In this review, the research progresses in understanding the roles and mechanisms of podoplanin in thromobotic diseases are summarized. The challenges of podoplanin-targeted approaches for disease prognosis and preventions are also discussed.

Interactions between Platelets and Tumor Microenvironment Components in Ovarian Cancer and Their Implications for Treatment and Clinical Outcomes

Platelets, the primary operatives of hemostasis that contribute to blood coagulation and wound healing after blood vessel injury, are also involved in pathological conditions, including cancer. Malignancy-associated thrombosis is common in ovarian cancer patients and is associated with poor clinical outcomes. Platelets extravasate into the tumor microenvironment in ovarian cancer and interact with cancer cells and non-cancerous elements. Ovarian cancer cells also activate platelets. The communication between activated platelets, cancer cells, and the tumor microenvironment is via various platelet membrane proteins or mediators released through degranulation or the secretion of microvesicles from platelets. These interactions trigger signaling cascades in tumors that promote ovarian cancer progression, metastasis, and neoangiogenesis. This review discusses how interactions between platelets, cancer cells, cancer stem cells, stromal cells, and the extracellular matrix in the tumor microenvironment influence ovarian cancer progression. It also presents novel potential therapeutic approaches toward this gynecological cancer.

LRRC superfamily expression in stromal cells predicts the clinical prognosis and platinum resistance of ovarian cancer

BACKGROUND

Leucine-rich repeat sequence domains are known to mediate protein‒protein interactions. Recently, some studies showed that members of the leucine rich repeat containing (LRRC) protein superfamily may become new targets for the diagnosis and treatment of tumours. However, it is not known whether any of the LRRC superfamily genes is expressed in the stroma of ovarian cancer (OC) and is associated with prognosis.

METHODS

The clinical data and transcriptional profiles of OC patients from the public databases TCGA (n = 427), GTEx (n = 88) and GEO (GSE40266 and GSE40595) were analysed by R software. A nomogram model was also generated through R. An online public database was used for auxiliary analysis of prognosis, immune infiltration and protein‒protein interaction (PPI) networks. Immunohistochemistry and qPCR were performed to determine the protein and mRNA levels of genes in high-grade serous ovarian cancer (HGSC) tissues of participants and the MRC-5 cell line induced by TGF-β.

RESULTS

LRRC15 and LRRC32 were identified as differentially expressed genes from the LRRC superfamily by GEO transcriptome analysis. PPI network analysis suggested that they were most enriched in TGF-β signalling. The TCGA-GTEx analysis results showed that only LRRC15 was highly expressed in both cancer-associated fibroblasts (CAFs) and the tumour stroma of OC and was related to clinical prognosis. Based on this, we developed a nomogram model to predict the incidence of adverse outcomes in OC. Moreover, LRRC15 was positively correlated with CAF infiltration and negatively correlated with CD8 + T-cell infiltration. As a single indicator, LRRC15 had the highest accuracy (AUC = 0.920) in predicting the outcome of primary platinum resistance.

CONCLUSIONS

The LRRC superfamily is related to the TGF-β pathway in the microenvironment of OC. LRRC15, as a stromal biomarker, can predict the clinical prognosis of HGSC and promote the immunosuppressive microenvironment. LRRC15 may be a potential therapeutic target for reversing primary resistance in OC.

The role of tumor-educated platelets in ovarian cancer: A comprehensive review and update

Platelets have recently surfaced as critical players in cancer metastasis and the local and systemic responses to tumor growth. The emerging concept of "Tumor-educated platelets (TEPs)" comprises the exchange of biomolecules between tumor cells and platelets, thereby leading to the "education" of platelets. Increased platelet numbers have long been associated with cancer patients' tumor metastasis and poor clinical prognosis. However, it is very recently that researchers have delved deeper into the tumor-microenvironment and probed the mechanism of interactions between tumor cells and platelets. Designing strategies to target the TEPs and the communications between platelets and tumor cells can prove to be a promising breakthrough in cancer therapy. Through this review, we aim to analyze the recent developments in this field and discuss the characteristics of TEPs, focusing on ovarian cancer-associated TEPs and their characteristics, the interplay between ovarian cancer-associated TEPs and cancer cells, and the purview of TEP-targeted cancer diagnosis and therapy, including platelet biomarkers and inhibitors.

Role of extracellular vesicles in cancer-specific interactions between tumour cells and the vasculature

Cancer progression impacts and exploits the vascular system in several highly consequential ways. Among different types of vascular cells, blood cells and mediators that are engaged in these processes, endothelial cells are at the centre of the underlying circuitry, as crucial constituents of angiogenesis, angiocrine stimulation, non-angiogenic vascular growth, interactions with the coagulation system and other responses. Tumour-vascular interactions involve soluble factors, extracellular matrix molecules, cell-cell contacts, as well as extracellular vesicles (EVs) carrying assemblies of molecular effectors. Oncogenic mutations and transforming changes in the cancer cell genome, epigenome and signalling circuitry exert important and often cancer-specific influences upon pathways of tumour-vascular interactions, including the biogenesis, content, and biological activity of EVs and responses of cancer cells to them. Notably, EVs may carry and transfer bioactive, oncogenic macromolecules (oncoproteins, RNA, DNA) between tumour and vascular cells and thereby elicit unique functional changes and forms of vascular growth and remodeling. Cancer EVs influence the state of the vasculature both locally and systemically, as exemplified by cancer-associated thrombosis. EV-mediated communication pathways represent attractive targets for therapies aiming at modulation of the tumour-vascular interface (beyond angiogenesis) and could also be exploited for diagnostic purposes in cancer.

Immunothrombosis and the Role of Platelets in Venous Thromboembolic Diseases

Venous thromboembolism (VTE) is the third leading cardiovascular cause of death and is conventionally treated with anticoagulants that directly antagonize coagulation. However, recent data have demonstrated that also platelets play a crucial role in VTE pathophysiology. In the current review, we outline how platelets are involved during all stages of experimental venous thrombosis. Platelets mediate initiation of the disease by attaching to the vessel wall upon which they mediate leukocyte recruitment. This process is referred to as immunothrombosis, and within this novel concept inflammatory cells such as leukocytes and platelets directly drive the progression of VTE. In addition to their involvement in immunothrombosis, activated platelets can directly drive venous thrombosis by supporting coagulation and secreting procoagulant factors. Furthermore, fibrinolysis and vessel resolution are (partly) mediated by platelets. Finally, we summarize how conventional antiplatelet therapy can prevent experimental venous thrombosis and impacts (recurrent) VTE in humans.

Therapeutic Strategies Focused on Cancer-Associated Hypercoagulation for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is associated with chemotherapy resistance and poor prognosis, especially in advanced cases. Although comprehensive genomic analyses have clarified the significance of genomic alterations such as ARID1A and PIK3CA mutations in OCCC, therapeutic strategies based on genomic alterations have not been confirmed. On the other hand, OCCC is clinically characterized by a high incidence of thromboembolism. Moreover, OCCC specifically shows high expression of tissue factor and interleukin-6, which play a critical role in cancer-associated hypercoagulation and may be induced by OCCC-specific genetic alterations or the endometriosis-related tumor microenvironment. In this review, we focused on the association between cancer-associated hypercoagulation and molecular biology in OCCC. Moreover, we reviewed the effectiveness of candidate drugs targeting hypercoagulation, such as tissue factor- or interleukin-6-targeting drugs, anti-inflammatory drugs, anti-hypoxia signaling drugs, anticoagulants, and combined immunotherapy with these drugs for OCCC. This review is expected to contribute to novel basic research and clinical trials for the prevention, early detection, and treatment of OCCC focused on hypercoagulation.