Stromal endothelial cells directly influence cancer progression

Daxx and HIRA go viral - How chromatin remodeling complexes affect DNA virus infection

Daxx and HIRA are key proteins in the host response to DNA virus infections. Daxx is involved in apoptosis, transcription regulation, and stress responses. During DNA virus infections, Daxx helps modulate the immune response and viral progression. Viruses like adenoviruses and herpesviruses can exploit Daxx to evade immune detection, either by targeting it for degradation or inhibiting its function. Daxx also interacts with chromatin to regulate transcription, which viruses can manipulate to enhance their own gene expression and replication. HIRA is a histone chaperone and reported to be essential for chromatin assembly and gene regulation. It plays a critical role in maintaining chromatin structure and modulating gene accessibility. During DNA virus infection, HIRA influences chromatin remodeling, affecting both viral and host DNA accessibility, which impacts viral replication and gene expression. Additionally, the histone variant H3.3 is crucial for maintaining active chromatin states. It is incorporated into chromatin independently of DNA replication and is associated with active gene regions. During viral infections, H3.3 dynamics can be altered, affecting viral genome accessibility and replication efficiency. Overall, Daxx and HIRA are integral to orchestrating viral infection programs, maintaining latency and/or persistence, and influencing virus-induced transformation by modulating chromatin dynamics and host immune responses, making them significant targets for therapeutic strategies once fully understood. Here, we summarize various DNA viruses and their crosstalk with Daxx and HIRA.

Cellular interactions within the immune microenvironment underpins resistance to cell cycle inhibition in breast cancers

Immune evasion by cancer cells involves reshaping the tumor microenvironment (TME) via communication with non-malignant cells. However, resistance-promoting interactions during treatment remain lesser known. Here we examine the composition, communication, and phenotypes of tumor-associated cells in serial biopsies from stage II and III high-risk estrogen receptor positive (ER+ ) breast cancers of patients receiving endocrine therapy (letrozole) as single agent or in combination with ribociclib, a CDK4/6-targeting cell cycle inhibitor. Single-cell RNA sequencing analyses on longitudinally collected samples show that in tumors overcoming the growth suppressive effects of ribociclib, first cancer cells upregulate cytokines and growth factors that stimulate immune-suppressive myeloid differentiation, resulting in reduced myeloid cell- CD8 + T-cell crosstalk via IL-15/18 signaling. Subsequently, tumors growing during treatment show diminished T-cell activation and recruitment. In vitro, ribociclib does not only inhibit cancer cell growth but also T cell proliferation and activation upon co-culturing. Exogenous IL-15 improves CDK4/6 inhibitor efficacy by augmenting T-cell proliferation and cancer cell killing by T cells. In summary, response to ribociclib in stage II and III high-risk ER +  breast cancer depends on the composition, activation phenotypes and communication network of immune cells.

Single-cell sequencing revealed the necessity of macrophages in brain microenvironment remodeling by breast cancer metastasis

Breast cancer is one of the most common cancers worldwide, 30-50 % of patients with advanced breast cancer develop brain metastasis, causing severe damage to their life quality. Due to the existence of the blood-brain barrier (BBB), brain lesions were recognized to be a unique microenvironment with limited infiltration of circulating immune cells and drugs. However, emerging studies reported the immunology of the brain tumor microenvironment (TME) and indicated the potential of immunotherapy against brain metastases. Therefore, it is of great value to comprehensively investigate the TME and identify the pro-tumoral mechanisms facilitating brain metastases and the crucial molecules involved in this process. In this research, we re-analyzed public data on three brain surgical specimens of breast cancer metastases and identified the immunosuppressive roles of macrophages in the metastatic TME. Then, we conducted the first single-cell RNA sequencing on a murine model of breast cancer brain metastasis. In the brain TME, immune cells showed prominent heterogeneity, especially the mononuclear phagocyte system (MPS). We identified the alteration of macrophage subclusters in the central nerve system (CNS) after breast cancer invasion and found that metastatic cancer cells re-shaped the TME cellular interactions for immune evasion and nutrition supply. Finally, this research could serve as a reference for further analysis of new therapies against brain metastatic lesions.

Single-Cell Transcriptomics Sheds Light on Tumor Evolution: Perspectives from City of Hope's Clinical Trial Teams

Tumor heterogeneity is a significant factor influencing cancer treatment effectiveness and can arise from genetic, epigenetic, and phenotypic variations among cancer cells. Understanding how tumor heterogeneity impacts tumor evolution and therapy response can lead to more effective treatments and improved patient outcomes. Traditional bulk genomic approaches fail to provide insights into cellular-level events, whereas single-cell RNA sequencing (scRNA-seq) offers transcriptomic analysis at the individual cell level, advancing our understanding of tumor growth, progression, and drug response. However, implementing single-cell approaches in clinical trials involves challenges, such as obtaining high-quality cells, technical variability, and the need for complex computational analysis. Effective implementation of single-cell genomics in clinical trials requires a collaborative "Team Medicine" approach, leveraging shared resources, expertise, and workflows. Here, we describe key technical considerations in implementing the collection of research biopsies and lessons learned from integrating scRNA-seq into City of Hope's clinical trial design, highlighting collaborative efforts between computational and clinical teams across breast, brain, and ovarian cancer studies to understand the composition, phenotypic state, and underlying resistance mechanisms within the tumor microenvironment.

Spatial organization and stochastic fluctuations of immune cells impact clinical responsiveness to immunotherapy in melanoma patients

High-dimensional, spatial single-cell technologies, such as CyTOF imaging mass cytometry (IMC), provide detailed information regarding locations of a large variety of cancer and immune cells in microscopic scales in tumor microarray slides obtained from patients prior to immune checkpoint inhibitor (ICI) therapy. An important question is how the initial spatial organization of these cells in the tumor microenvironment (TME) changes with time and regulates tumor growth and eventually outcomes as patients undergo ICI therapy. Utilizing IMC data of melanomas of patients who later underwent ICI therapy, we develop a spatially resolved interacting cell system model that is calibrated against patient response data to address the above question. We find that the tumor fate in these patients is determined by the spatial organization of activated CD8+ T cells, macrophages, and melanoma cells and the interplay between these cells that regulate exhaustion of CD8+ T cells. We find that fencing of tumor cell boundaries by exhausted CD8+ T cells is dynamically generated from the initial conditions that can play a protumor role. Furthermore, we find that specific spatial features such as co-clustering of activated CD8+ T cells and macrophages in the pretreatment samples determine the fate of the tumor progression, despite stochastic fluctuations and changes over the treatment course. Our framework enables the determination of mechanisms of interplay between a key subset of tumor and immune cells in the TME that regulate clinical response to ICIs.

Targeting the tumour vasculature: from vessel destruction to promotion

As angiogenesis was recognized as a core hallmark of cancer growth and survival, several strategies have been implemented to target the tumour vasculature. Yet to date, attempts have rarely been so diverse, ranging from vessel growth inhibition and destruction to vessel normalization, reprogramming and vessel growth promotion. Some of these strategies, combined with standard of care, have translated into improved cancer therapies, but their successes are constrained to certain cancer types. This Review provides an overview of these vascular targeting approaches and puts them into context based on our subsequent improved understanding of the tumour vasculature as an integral part of the tumour microenvironment with which it is functionally interlinked. This new knowledge has already led to dual targeting of the vascular and immune cell compartments and sets the scene for future investigations of possible alternative approaches that consider the vascular link with other tumour microenvironment components for improved cancer therapy.

CAFs vs. TECs: when blood feuds fuel cancer progression, dissemination and therapeutic resistance

Neoplastic progression involves complex interactions between cancer cells and the surrounding stromal milieu, fostering microenvironments that crucially drive tumor progression and dissemination. Of these stromal constituents, cancer-associated fibroblasts (CAFs) emerge as predominant inhabitants within the tumor microenvironment (TME), actively shaping multiple facets of tumorigenesis, including cancer cell proliferation, invasiveness, and immune evasion. Notably, CAFs also orchestrate the production of pro-angiogenic factors, fueling neovascularization to sustain the metabolic demands of proliferating cancer cells. Moreover, CAFs may also directly or indirectly affect endothelial cell behavior and vascular architecture, which may impact in tumor progression and responses to anti-cancer interventions. Conversely, tumor endothelial cells (TECs) exhibit a corrupted state that has been shown to affect cancer cell growth and inflammation. Both CAFs and TECs are emerging as pivotal regulators of the TME, engaging in multifaceted biological processes that significantly impact cancer progression, dissemination, and therapeutic responses. Yet, the intricate interplay between these stromal components and the orchestrated functions of each cell type remains incompletely elucidated. In this review, we summarize the current understanding of the dynamic interrelationships between CAFs and TECs, discussing the challenges and prospects for leveraging their interactions towards therapeutic advancements in cancer.

Clinical Implications and Molecular Features of Extracellular Matrix Networks in Soft Tissue Sarcomas

PURPOSE

The landscape of extracellular matrix (ECM) alterations in soft tissue sarcomas (STS) remains poorly characterized. We aimed to investigate the tumor ECM and adhesion signaling networks present in STS and their clinical implications.

EXPERIMENTAL DESIGN

Proteomic and clinical data from 321 patients across 11 histological subtypes were analyzed to define ECM and integrin adhesion networks. Subgroup analysis was performed in leiomyosarcomas (LMS), dedifferentiated liposarcomas (DDLPS), and undifferentiated pleomorphic sarcomas (UPS).

RESULTS

This analysis defined subtype-specific ECM profiles including enrichment of basement membrane proteins in LMS and ECM proteases in UPS. Across the cohort, we identified three distinct coregulated ECM networks which are associated with tumor malignancy grade and histological subtype. Comparative analysis of LMS cell line and patient proteomic data identified the lymphocyte cytosolic protein 1 cytoskeletal protein as a prognostic factor in LMS. Characterization of ECM network events in DDLPS revealed three subtypes with distinct oncogenic signaling pathways and survival outcomes. Evaluation of the DDLPS subtype with the poorest prognosis nominates ECM remodeling proteins as candidate antistromal therapeutic targets. Finally, we define a proteoglycan signature that is an independent prognostic factor for overall survival in DDLPS and UPS.

CONCLUSIONS

STS comprise heterogeneous ECM signaling networks and matrix-specific features that have utility for risk stratification and therapy selection, which could in future guide precision medicine in these rare cancers.

Comprehensive landscape of integrator complex subunits and their association with prognosis and tumor microenvironment in gastric cancer

Backgrounds

The integrator complex (INT) is a multiprotein assembly in gene transcription. Although several subunits of INT complex have been implicated in multiple cancers, the complex's role in gastric cancer (GC) is poorly understood.

Methods

The gene expressions, prognostic values, and the associations with microsatellite instability (MSI) of INT subunits were confirmed by GEO and The Cancer Genome Atlas (TCGA) databases. cBioPortal, GeneMANIA, TISIDB, and MCPcounter algorithm were adopted to investigate the mutation frequency, protein-protein interaction network, and the association with immune cells of INT subunits in GC. Additionally, in vitro experiments were performed to confirm the role of INTS11 in pathogenesis of GC.

Results

The mRNA expression levels of INTS2/4/5/7/8/9/10/11/12/13/14 were significantly elevated both in GSE183904 and TCGA datasets. Through functional enrichment analysis, the functions of INT subunits were mainly associated with snRNA processing, INT, and DNA-directed 5'-3' RNA polymerase activity. Moreover, these INT subunit expressions were associated with tumor-infiltrating lymphocytes and MSI in GC. In vitro experiments demonstrated that knockdown of the catalytic core INTS11 in GC cells inhibits cell proliferation ability. INTS11 overexpression showed opposite effects.

Conclusions

Our data demonstrate that the INT complex might act as an oncogene and can be used as a prognosis biomarker for GC.

Roles of lysophosphatidic acid (LPA) receptor-mediated signaling in cellular functions modulated by endothelial cells in pancreatic cancer cells under hypoxic conditions

BACKGROUND

In the tumor environment, malignant characteristics of cancer cells are promoted by stromal cells under hypoxia. It is unknown whether lysophosphatidic acid (LPA) receptor-mediated signaling is involved in the regulation of cellular functions by endothelial cells in pancreatic cancer cells under hypoxic conditions.

METHODS

Pancreatic cancer (PANC-1) cells were co-cultured with endothelial (F2) cells and F2 cell supernatants at 21% and 1% O2. The Cell Culture Insert was used to assess the cell motile activity. The cell growth and viability to cisplatin (CDDP) were measured, using the Cell Counting Kit-8.

RESULTS

LPA receptor expression levels were changed in PANC-1 cells co-cultured with F2 cells at 21% and 1% O2. The cell motile activities of PANC-1 cells co-cultured with F2 cells at 21% and 1% O2 were markedly elevated, compared with PANC-1 cells alone. The cell viabilities to CDDP of PANC-1 cells co-cultured with F2 cell supernatants at 21% and 1% O2 were regulated by the activation of LPA receptors.

CONCLUSION

These results suggest that LPA receptor-mediated signaling plays an important role in the modulation of pancreatic cancer cell functions by endothelial cells under hypoxic conditions.

Identification a unique disulfidptosis classification regarding prognosis and immune landscapes in thyroid carcinoma and providing therapeutic strategies

BACKGROUND

Thyroid carcinoma (THCA) is a common type of cancer worldwide, and its incidence has been increasing in recent years. Disulfidptosis, a recently defined form of metabolic-related regulated cell death (RCD), has been shown to play a sophisticated role in antitumor immunity. However, its mechanisms and functions are still poorly understood and the association between disulfidptosis and the prognosis of patients with papillary thyroid carcinoma remains to be elucidated. This study aims to investigate the connection between disulfidptosis and the prognosis of thyroid cancer, while also developing a prognostic index based on disulfidptosis genes.

MATERIALS AND METHODS

We utilized 24 genes associated with disulfidptosis to create the classification and model. To gather data, we sourced gene expression profiles, somatic mutation information, copy number variation data, and corresponding clinical data from the TCGA database for patients with thyroid cancer. Additionally, we obtained single-cell transcriptome data GSE184362 from the Gene Expression Omnibus (GEO) database for further analysis.

RESULTS

In this study, we utilized 24 genes associated with disulfidptosis to identify two distinct groups with different biological processes using non-negative matrix factorization (NMF). Our findings showed that Cluster 1 is associated with chemokines, interleukins, interferons, checkpoint genes, and other important components of the immune microenvironment. Moreover, cluster 1 patients with high IPS scores may be more sensitive to immunotherapy. We also provide drug therapeutic strategies for each cluster patients based on the IC50 of each drug. The Enet model was chosen as the optimal model with the highest C-index and showed that patients with high risk had a worse prognosis and weak cell-to-cell interactions in THCA. Finally, we established a nomogram model based on multivariable cox and logistic regression analyses to predict the overall survival of THCA patients.

CONCLUSION

This research provides new insight into the impact of disulfidptosis on THCA. Through a thorough examination of disulfidptosis, a new classification system has been developed that can effectively predict the clinical prognosis and drug sensitivity of THCA patients.

Analysis of the interferon-γ-induced secretome of intestinal endothelial cells: putative impact on epithelial barrier dysfunction in IBD

The development of inflammatory bowel diseases (IBD) involves the breakdown of two barriers: the epithelial barrier and the gut-vascular barrier (GVB). The destabilization of each barrier can promote initiation and progression of the disease. Interestingly, first evidence is available that both barriers are communicating through secreted factors that may accordingly serve as targets for therapeutic modulation of barrier functions. Interferon (IFN)-γ is among the major pathogenesis factors in IBD and can severely impair both barriers. In order to identify factors transmitting signals from the GVB to the epithelial cell barrier, we analyzed the secretome of IFN-γ-treated human intestinal endothelial cells (HIEC). To this goal, HIEC were isolated in high purity from normal colon tissues. HIEC were either untreated or stimulated with IFN-γ (10 U/mL). After 48 h, conditioned media (CM) were harvested and subjected to comparative hyper reaction monitoring mass spectrometry (HRM™ MS). In total, 1,084 human proteins were detected in the HIEC-CM. Among these, 43 proteins were present in significantly different concentrations between the CM of IFN-γ- and control-stimulated HIEC. Several of these proteins were also differentially expressed in various murine colitis models as compared to healthy animals supporting the relevance of these proteins secreted by inflammatory activated HIEC in the inter-barrier communication in IBD. The angiocrine pathogenic impact of these differentially secreted HIEC proteins on the epithelial cell barrier and their perspectives as targets to treat IBD by modulation of trans-barrier communication is discussed in detail.

Understanding the squamous cell carcinoma immune microenvironment

Primary cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer with a rising incidence of about 1.8 million in the United States annually. Primary cSCC is usually curable by surgery; however, in some cases, cSCC eventuates in nodal metastasis and death from disease specific death. cSCC results in up to 15,000 deaths each year in the United States. Until recently, non-surgical options for treatment of locally advanced or metastatic cSCC were largely ineffective. With the advent of checkpoint inhibitor immunotherapy, including cemiplimab and pembrolizumab, response rates climbed to 50%, representing a vast improvement over chemotherapeutic agents used previously. Herein, we discuss the phenotype and function of SCC associated Langerhans cells, dendritic cells, macrophages, myeloid derived suppressor cells and T cells as well as SCC-associated lymphatics and blood vessels. Possible role(s) of SCC-associated cytokines in progression and invasion are reviewed. We also discuss the SCC immune microenvironment in the context of currently available and pipeline therapeutics.

Role of Lymphatic Endothelium in Vascular Escape of Engineered Human Breast Microtumors

Introduction

Lymphatic vasculature provides a route for metastasis to secondary sites in the body. The role of the lymphatic endothelium in mediating the entry of breast cancer cells into the vasculature remains unclear.

Methods

In this study, we formed aggregates of MDA-MB-231 human breast carcinoma cells next to human microvascular lymphatic endothelial cell (LEC)-lined cavities in type I collagen gels to model breast microtumors and lymphatic vessels, respectively. We tracked invasion and escape of breast microtumors into engineered lymphatics or empty cavities under matched flow rates for up to sixteen days.

Results

After coming into contact with a lymphatic vessel, tumor cells escape by moving between the endothelium and the collagen wall, between endothelial cells, and/or into the endothelial lumen. Over time, tumor cells replace the LECs within the vessel wall and create regions devoid of endothelium. The presence of lymphatic endothelium slows breast tumor invasion and escape, and addition of LEC-conditioned medium to tumors is sufficient to reproduce nearly all of these inhibitory effects.

Conclusions

This work sheds light on the interactions between breast cancer cells and lymphatic endothelium during vascular escape and reveals an inhibitory role for the lymphatic endothelium in breast tumor invasion and escape.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-022-00745-9.

A self-guidance biological hybrid drug delivery system driven by anaerobes to inhibit the proliferation and metastasis of colon cancer

Colorectal cancer is often accompanied by multiple organ metastasis. Anaerobic Bifidobacterium Infantis (BI) bacterial can selectively grow in hypoxic colorectal tumor microenvironment (TME), to own the natural advantage of preferentially colorectal tumor targeting. Herein, a self-guidance biological hybrid drug delivery system (BI-ES-FeAlg/DOX) based on BI was constructed to inhibit the proliferation and metastasis of colon cancer. Results demonstrated that BI-ES-FeAlg/DOX could overcome physical barriers to target and accumulate in colon tumor tissues. Then DOX was released to kill tumor cells along with the phase transition (solid to liquid) of FeAlg hydrogel, due to Fe³⁺ was reduced to Fe²⁺by intracellular GSH. Meanwhile, BI-ES selectively colonized into tumors and expressed endostatin (ES) protein to down-regulate VEGF and bFGF expression, exerting anti-angiogenic effect. Moreover, FeAlg catalyzed H₂O₂ in the local tumor to generate cytotoxic ·OH, further enhancing the antitumor effect. The pharmacodynamic result in AOM/DSS model proved that BI-ES-FeAlg/DOX had the best therapeutic effect, with the final V/V₀ of 2.19 ± 0.57, which was significantly lower than the other groups. Meanwhile, on CT-26 tumor-bearing model, it also showed an outstanding anti-tumor effect with inhibition rate of 82.12% ± 3.08%. In addition, lung metastases decreased significantly in tumor metastasis model after BI-ES-FeAlg/DOX treatment.

Tumor Microenvironment Characterization in Breast Cancer Identifies Prognostic Pathway Signatures

Breast cancer is one of the most common female malignancies worldwide. Due to its early metastases formation and a high degree of malignancy, the 10 year-survival rate of metastatic breast cancer does not exceed 30%. Thus, more precise biomarkers are urgently needed. In our study, we first estimated the tumor microenvironment (TME) infiltration using the xCell algorithm. Based on TME infiltration, the three main TME clusters were identified using consensus clustering. Our results showed that the three main TME clusters cause significant differences in survival rates and TME infiltration patterns (log-rank test, p = 0.006). Then, multiple machine learning algorithms were used to develop a nine-pathway-based TME-related risk model to predict the prognosis of breast cancer (BRCA) patients (the immune-related pathway-based risk score, defined as IPRS). Based on the IPRS, BRCA patients were divided into two subgroups, and patients in the IPRS-low group presented significantly better overall survival (OS) rates than the IPRS-high group (log-rank test, p < 0.0001). Correlation analysis revealed that the IPRS-low group was characterized by increases in immune-related scores (cytolytic activity (CYT), major histocompatibility complex (MHC), T cell-inflamed immune gene expression profile (GEP), ESTIMATE, immune, and stromal scores) while exhibiting decreases in tumor purity, suggesting IPRS-low patients may have a strong immune response. Additionally, the gene-set enrichment analysis (GSEA) result confirmed that the IPRS-low patients were significantly enriched in several immune-associated signaling pathways. Furthermore, multivariate Cox analysis revealed that the IPRS was an independent prognostic biomarker after adjustment by clinicopathologic characteristics. The prognostic value of the IPRS model was further validated in three external validation cohorts. Altogether, our findings demonstrated that the IPRS was a powerful predictor to screen out certain populations with better prognosis in breast cancer and may serve as a potential biomarker guiding clinical treatment decisions.

Endothelial Nogo-B Suppresses Cancer Cell Proliferation via a Paracrine TGF-β/Smad Signaling

Nogo-B has been reported to play a critical role in angiogenesis and the repair of damaged blood vessels; however, its role in the tumor microenvironment remains unclear. Here, we observed the differential expression of Nogo-B in endothelial cells from hepatocellular carcinoma (HCC) and glioma samples. Downregulation of Nogo-B expression correlated with the malignant phenotype of cancer and a poor prognosis for patients. In subsequent studies, endothelial Nogo-B inhibition robustly promoted the growth of HCC or glioma xenografts in nude mice. Intriguingly, endothelial Nogo-B silencing dramatically suppressed endothelial cell expansion and tumor angiogenesis, but potently enhanced the proliferation of neighboring HCC and glioma cells. Based on the results of the ELISA assay, Nogo-B silencing reduced TGF-β production in endothelial cells, which attenuated the phosphorylation and nuclear translocation of Smad in neighboring cancer cells. The endothelial Nogo-B silencing-mediated increase in cancer cell proliferation was abolished by either a TGF-β neutralizing antibody or TGF-β receptor inhibitor, indicating the essential role for TGF-β in endothelial Nogo-B-mediated suppression of cancer growth. These findings not only broaden our understanding of the crosstalk between cancer cells and endothelial cells but also provide a novel prognostic biomarker and a therapeutic target for cancer treatments.

The Differential Paracrine Role of the Endothelium in Prostate Cancer Cells

Simple Summary

A growing body of literature supports the concept that a tumor mass is under the strict control of the microvascular endothelium and that the perfusion of oxygen and nutrients by capillary vessels to the tumor mass is reinforced by potent paracrine activity from the vascular endothelial cells. In our study, we investigate the biological and molecular implications of the paracrine crosstalk between vascular endothelial cells and prostate cancer cells. Our results indicate that the endothelial cells were able to secrete molecular signals that promote the proliferation and growth of low and highly aggressive prostate cancer cells and selectively increased the migration, invasion and metastatic potential of highly aggressive prostate cancer cells. The molecular analyses indicated that endothelial cells induced a differential effect on gene expression profile when comparing low versus highly aggressive prostate cancer cells, causing an enrichment of epigenetic changes in migratory pathways in highly aggressive prostate cancer cells. In conclusion, our results indicate that endothelial cells release signals that favor tumor growth and aggressiveness and that this interaction may play an important role in the progression of prostate cancer.

Abstract

The survival of patients with solid tumors, such as prostate cancer (PCa), has been limited and fleeting with anti-angiogenic therapies. It was previously thought that the mechanism by which the vasculature regulates tumor growth was driven by a passive movement of oxygen and nutrients to the tumor tissue. However, previous evidence suggests that endothelial cells have an alternative role in changing the behavior of tumor cells and contributing to cancer progression. Determining the impact of molecular signals/growth factors released by endothelial cells (ECs) on established PCa cell lines in vitro and in vivo could help to explain the mechanism by which ECs regulate tumor growth. Using cell-conditioned media collected from HUVEC (HUVEC-CM), our data show the stimulated proliferation of all the PCa cell lines tested. However, in more aggressive PCa cell lines, HUVEC-CM selectively promoted migration and invasion in vitro and in vivo. Using a PCa-cell-line-derived xenograft model co-injected with HUVEC or preincubated with HUVEC-CM, our results are consistent with the in vitro data, showing enhanced tumor growth, increased tumor microvasculature and promoted metastasis. Gene set enrichment analyses from RNA-Seq gene expression profiles showed that HUVEC-CM induced a differential effect on gene expression when comparing low versus highly aggressive PCa cell lines, demonstrating epigenetic and migratory pathway enrichments in highly aggressive PCa cells. In summary, paracrine stimulation by HUVEC increased PCa cell proliferation and tumor growth and selectively promoted migration and metastatic potential in more aggressive PCa cell lines.

Extracellular vesicles as central regulators of blood vessel function in cancer

Blood vessels deliver oxygen and nutrients that sustain tumor growth and enable the dissemination of cancer cells to distant sites and the recruitment of intratumoral immune cells. In addition, the structural and functional abnormalities of the tumor vasculature foster the development of an aggressive tumor microenvironment and impair the efficacy of existing cancer therapies. Extracellular vesicles (EVs) have emerged as major players of tumor progression, and a growing body of evidence has demonstrated that EVs derived from cancer cells trigger multiple responses in endothelial cells that alter blood vessel function in tumors. EV-mediated signaling in endothelial cells can occur through the transfer of functional cargos such as miRNAs, lncRNAs, cirRNAs, and proteins. Moreover, membrane-bound proteins in EVs can elicit receptor-mediated signaling in endothelial cells. Together, these mechanisms reprogram endothelial cells and contribute to the sustained exacerbated angiogenic signaling typical of tumors, which, in turn, influences cancer progression. Targeting these angiogenesis-promoting EV-dependent mechanisms may offer additional strategies to normalize tumor vasculature. Here, we discuss the current knowledge pertaining to the contribution of cancer cell-derived EVs in mechanisms regulating blood vessel functions in tumors. Moreover, we discuss the translational opportunities in targeting the dysfunctional tumor vasculature using EVs and highlight the open questions in the field of EV biology that can be addressed using mass spectrometry-based proteomics analysis.

Stromal Co-Cultivation for Modeling Breast Cancer Dormancy in the Bone Marrow

Cancers metastasize to the bone marrow before primary tumors can be detected. Bone marrow micrometastases are resistant to therapy, and while they are able to remain dormant for decades, they recur steadily and result in incurable metastatic disease. The bone marrow microenvironment maintains the dormancy and chemoresistance of micrometastases through interactions with multiple cell types and through structural and soluble factors. Modeling dormancy in vitro can identify the mechanisms of these interactions. Modeling also identifies mechanisms able to disrupt these interactions or define novel interactions that promote the reawakening of dormant cells. The in vitro modeling of the interactions of cancer cells with various bone marrow elements can generate hypotheses on the mechanisms that control dormancy, treatment resistance and reawakening in vivo. These hypotheses can guide in vivo murine experiments that have high probabilities of succeeding in order to verify in vitro findings while minimizing the use of animals in experiments. This review outlines the existing data on predominant stromal cell types and their use in 2D co-cultures with cancer cells.

Targeting of the Peritumoral Adipose Tissue Microenvironment as an Innovative Antitumor Therapeutic Strategy

The tumor microenvironment (TME) plays a key role in promoting and sustaining cancer growth. Adipose tissue (AT), due to its anatomical distribution, is a prevalent component of TME, and contributes to cancer development and progression. Cancer-associated adipocytes (CAAs), reprogrammed by cancer stem cells (CSCs), drive cancer progression by releasing metabolites and inflammatory adipokines. In this review, we highlight the mechanisms underlying the bidirectional crosstalk among CAAs, CSCs, and stromal cells. Moreover, we focus on the recent advances in the therapeutic targeting of adipocyte-released factors as an innovative strategy to counteract cancer progression.

Transforming Growth Factor-Beta Orchestrates Tumour and Bystander Cells in B-Cell Non-Hodgkin Lymphoma

Transforming growth factor-beta (TGFB) is a critical regulator of normal haematopoiesis. Dysregulation of the TGFB pathway is associated with numerous haematological malignancies including myelofibrosis, acute myeloid leukaemia, and lymphoid disorders. TGFB has classically been seen as a negative regulator of proliferation in haematopoiesis whilst stimulating differentiation and apoptosis, as required to maintain homeostasis. Tumours frequently develop intrinsic resistant mechanisms to homeostatic TGFB signalling to antagonise its tumour-suppressive functions. Furthermore, elevated levels of TGFB enhance pathogenesis through modulation of the immune system and tumour microenvironment. Here, we review recent advances in the understanding of TGFB signalling in B-cell malignancies with a focus on the tumour microenvironment. Malignant B-cells harbour subtype-specific alterations in TGFB signalling elements including downregulation of surface receptors, modulation of SMAD signalling proteins, as well as genetic and epigenetic aberrations. Microenvironmental TGFB generates a protumoural niche reprogramming stromal, natural killer (NK), and T-cells. Increasingly, evidence points to complex bi-directional cross-talk between cells of the microenvironment and malignant B-cells. A greater understanding of intercellular communication and the context-specific nature of TGFB signalling may provide further insight into disease pathogenesis and future therapeutic strategies.

Thorny ground, rocky soil: Tissue-specific mechanisms of tumor dormancy and relapse

Disseminated tumor cells (DTCs) spread systemically yet distinct patterns of metastasis indicate a range of tissue susceptibility to metastatic colonization. Distinctions between permissive and suppressive tissues are still being elucidated at cellular and molecular levels. Although there is a growing appreciation for the role of the microenvironment in regulating metastatic success, we have a limited understanding of how diverse tissues regulate DTC dormancy, the state of reversible quiescence and subsequent awakening thought to contribute to delayed relapse. Several themes of microenvironmental regulation of dormancy are beginning to emerge, including vascular association, co-option of pre-existing niches, metabolic adaptation, and immune evasion, with tissue-specific nuances. Conversely, DTC awakening is often associated with injury or inflammation-induced activation of the stroma, promoting a proliferative environment with DTCs following suit. We review what is known about tissue-specific regulation of tumor dormancy on a tissue-by-tissue basis, profiling major metastatic organs including the bone, lung, brain, liver, and lymph node. An aerial view of the barriers to metastatic growth may reveal common targets and dependencies to inform the therapeutic prevention of relapse.

Recent Developments in the Study of the Microenvironment of Cancer and Drug Delivery

Cancer is characterized by disrupted molecular variables caused by cells that deviate from regular signal transduction. The uncontrolled segment of such cancerous cells annihilates most of the tissues that contact them. Gene therapy, immunotherapy, and nanotechnology advancements have resulted in novel strategies for anticancer drug delivery. Furthermore, diverse dispersion of nanoparticles in normal stroma cells adversely affects the healthy cells and disrupts the crosstalk of tumour stroma. It can contribute to cancer cell progression inhibition and, conversely, to acquired resistance, enabling cancer cell metastasis and proliferation. The tumour's microenvironment is critical in controlling the dispersion and physiological activities of nano-chemotherapeutics which is one of the targeted drug therapy. As it is one of the methods of treating cancer that involves the use of medications or other substances to specifically target and kill off certain subsets of malignant cells. A targeted therapy may be administered alone or in addition to more conventional methods of care like surgery, chemotherapy, or radiation treatment. The tumour microenvironment, stromatogenesis, barriers and advancement in the drug delivery system across tumour tissue are summarised in this review.

The cancer-inhibitory effects of proliferating tumor-residing fibroblasts

Initiation, local progression, and metastasis of cancer are associated with specific morphological, molecular, and functional changes in the extracellular matrix and the fibroblasts within the tumor microenvironment (TME). In the early stages of tumor development, fibroblasts are an obstacle that cancer cells must surpass or nullify to progress. Thus, in early tumor progression, specific signaling from cancer cells activates bio-pathways, which abolish the innate anticancer properties of fibroblasts and convert a high proportion of them to tumor-promoting cancer-associated fibroblasts (CAFs). Following this initial event, a wide spectrum of gene expression changes gradually leads to the development of a stromal fibroblast population with complex heterogeneity, creating fibroblast subtypes with characteristic profiles, which may alternate between being tumor-promotive and tumor-suppressive, topologically and chronologically in the TME. These fibroblast subtypes form the tumor's histological landscape including areas of cancer growth, inflammation, angiogenesis, invasion fronts, proliferating and non-proliferating fibroblasts, cancer-cell apoptosis, fibroblast apoptosis, and necrosis. These features reflect general deregulation of tissue homeostasis within the TME. This review discusses fundamental and current knowledge that has established the existence of anticancer fibroblasts within the various interacting elements of the TME. It is proposed that the maintenance of fibroblast proliferation is an essential parameter for the activation of their anticancer capacity, similar to that by which normal fibroblasts would be activated in wound repair, thus maintaining tissue homeostasis. Encouragement of research in this direction may render new means of cancer therapy and a greater understanding of tumor progression.

Nucleic Acid Sensing in the Tumor Vasculature

Endothelial cells form a powerful interface between tissues and immune cells. In fact, one of the underappreciated roles of endothelial cells is to orchestrate immune attention to specific sites. Tumor endothelial cells have a unique ability to dampen immune responses and thereby maintain an immunosuppressive microenvironment. Recent approaches to trigger immune responses in cancers have focused on activating nucleic acid sensors, such as cGAS-STING, in combination with immunotherapies. In this review, we present a case for targeting nucleic acid-sensing pathways within the tumor vasculature to invigorate tumor-immune responses. We introduce two specific nucleic acid sensors-the DNA sensor TREX1 and the RNA sensor RIG-I-and discuss their functional roles in the vasculature. Finally, we present perspectives on how these nucleic acid sensors in the tumor endothelium can be targeted in an antiangiogenic and immune activation context. We believe understanding the role of nucleic acid-sensing in the tumor vasculature can enhance our ability to design more effective therapies targeting the tumor microenvironment by co-opting both vascular and immune cell types.

Matricellular Protein SPARCL1 Regulates Blood Vessel Integrity and Antagonizes Inflammatory Bowel Disease

BACKGROUND

The understanding of vascular plasticity is key to defining the role of blood vessels in physiologic and pathogenic processes. In the present study, the impact of the vascular quiescence marker SPARCL1 on angiogenesis, capillary morphogenesis, and vessel integrity was evaluated.

METHODS

Angiogenesis was studied using the metatarsal test, an ex vivo model of sprouting angiogenesis. In addition, acute and chronic dextran sodium sulfate colitis models with SPARCL1 knockout mice were applied.

RESULTS

This approach indicated that SPARCL1 inhibits angiogenesis and supports vessel morphogenesis and integrity. Evidence was provided that SPARCL1-mediated stabilization of vessel integrity counteracts vessel permeability and inflammation in acute and chronic dextran sodium sulfate colitis models. Structure-function analyses of purified SPARCL1 identified the acidic domain of the protein necessary for its anti-angiogenic activity.

CONCLUSIONS

Our findings inaugurate SPARCL1 as a blood vessel-derived anti-angiogenic molecule required for vessel morphogenesis and integrity. SPARCL1 opens new perspectives as a vascular marker of susceptibility to colitis and as a therapeutic molecule to support blood vessel stability in this disease.

Angiocrine Regulation of Epithelial Barrier Integrity in Inflammatory Bowel Disease

Inflammatory bowel disease describes chronic inflammatory disorders. The incidence of the disease is rising. A major step in disease development is the breakdown of the epithelial cell barrier. Numerous blood vessels are directly located underneath this barrier. Diseased tissues are heavily vascularized and blood vessels significantly contribute to disease progression. The gut-vascular barrier (GVB) is an additional barrier controlling the entry of substances into the portal circulation and to the liver after passing the first epithelial barrier. The presence of the GVB rises the question, whether the vascular and endothelial barriers may communicate bi-directionally in the regulation of selective barrier permeability. Communication from epithelial to endothelial cells is well-accepted. In contrast, little is known on the respective backwards communication. Only recently, perfusion-independent angiocrine functions of endothelial cells were recognized in a way that endothelial cells release specific soluble factors that may directly act on the epithelial barrier. This review discusses the putative involvement of angiocrine inter-barrier communication in the pathogenesis of IBD.

Dapagliflozin alleviates cardiac fibrosis through suppressing EndMT and fibroblast activation via AMPKα/TGF-β/Smad signalling in type 2 diabetic rats

Diabetic cardiomyopathy (DCM) is one of the leading causes of heart failure in patients with diabetes mellitus, with limited effective treatments. The cardioprotective effects of sodium‐glucose cotransporter 2(SGLT2) inhibitors have been supported by amounts of clinical trials, which largely fills the gap. However, the underlying mechanism still needs to be further explored, especially in terms of its protection against cardiac fibrosis, a crucial pathophysiological process during the development of DCM. Besides, endothelial‐to‐mesenchymal transition (EndMT) has been reported to play a pivotal role in fibroblast multiplication and cardiac fibrosis. This study aimed to evaluate the effect of SGLT2 inhibitor dapagliflozin (DAPA) on DCM especially for cardiac fibrosis and explore the underlying mechanism. In vivo, the model of type 2 diabetic rats was built with high‐fat feeding and streptozotocin injection. Untreated diabetic rats showed cardiac dysfunction, increased myocardial fibrosis and EndMT, which was attenuated after treatment with DAPA and metformin. In vitro, HUVECs and primary cardiac fibroblasts were treated with DAPA and exposed to high glucose (HG). HG‐induced EndMT in HUVECs and collagen secretion of fibroblasts were markedly inhibited by DAPA. Up‐regulation of TGF‐β/Smad signalling and activity inhibition of AMPKα were also reversed by DAPA treatment. Then, AMPKα siRNA and compound C abrogated the anti‐EndMT effects of DAPA in HUVECs. From above all, our study implied that DAPA can protect against DCM and myocardial fibrosis through suppressing fibroblast activation and EndMT via AMPKα‐mediated inhibition of TGF‐β/Smad signalling.

Inhibition of Tunneling Nanotubes between Cancer Cell and the Endothelium Alters the Metastatic Phenotype

The interaction of tumor cells with blood vessels is one of the key steps during cancer metastasis. Metastatic cancer cells exhibit phenotypic state changes during this interaction: (1) they form tunneling nanotubes (TNTs) with endothelial cells, which act as a conduit for intercellular communication; and (2) metastatic cancer cells change in order to acquire an elongated phenotype, instead of the classical cellular aggregates or mammosphere-like structures, which it forms in three-dimensional cultures. Here, we demonstrate mechanistically that a siRNA-based knockdown of the exocyst complex protein Sec3 inhibits TNT formation. Furthermore, a set of pharmacological inhibitors for Rho GTPase–exocyst complex-mediated cytoskeletal remodeling is introduced, which inhibits TNT formation, and induces the reversal of the more invasive phenotype of cancer cell (spindle-like) into a less invasive phenotype (cellular aggregates or mammosphere). Our results offer mechanistic insights into this nanoscale communication and shift of phenotypic state during cancer–endothelial interactions.

Nanotechnology-Based Strategies to Evaluate and Counteract Cancer Metastasis and Neoangiogenesis

Cancer metastasis is the major cause of cancer-related morbidity and mortality. It represents one of the greatest challenges in cancer therapy, both because of the ability of metastatic cells to spread into different organs, and because of the consequent heterogeneity that characterizes primary and metastatic tumors. Nanomaterials can potentially be used as targeting or detection agents owing to unique chemical and physical features that allow tailored and tunable theranostic functions. This review highlights nanomaterial-based approaches in the detection and treatment of cancer metastasis, with a special focus on the evaluation of nanostructure effects on cell migration, invasion, and angiogenesis in the tumor microenvironment.

Chronic Inflammation and Cancer: The Role of Endothelial Dysfunction and Vascular Inflammation

Long-lasting subclinical inflammation is associated with a wide range of human diseases, particularly at a middle and older age. Recent reports showed that there is a direct causal link between inflammation and cancer development, as several cancers were found to be associated with chronic inflammatory conditions. In patients with cancer, healthy endothelial cells regulate vascular homeostasis, and it is believed that they can limit tumor growth, invasiveness, and metastasis. Conversely, dysfunctional endothelial cells that have been exposed to the inflammatory tumor microenvironment can support cancer progression and metastasis. Dysfunctional endothelial cells can exert these effects via diverse mechanisms, including dysregulated adhesion, permeability, and activation of NF-κB and STAT3 signaling. In this review, we highlight the role of vascular inflammation in predisposition to cancer within the context of two common disease risk factors: obesity and smoking. In addition, we discuss the molecular triggers, pathophysiological mechanisms, and the biological consequences of vascular inflammation during cancer development and metastasis. Finally, we summarize the current therapies and pharmacological agents that target vascular inflammation and endothelial dysfunction.

Omega-3 Eicosapentaenoic Acid Reduces Prostate Tumor Vascularity

The impact of omega (ω)-3 fatty acids on prostate cancer is controversial in epidemiological studies but experimental studies suggest a protective effect. However, little is known about the mechanism of action. Here, we studied the effects of purified fatty acid molecules on prostate tumor progression using the TRAMP-C2 syngeneic immunocompetent mouse model. Compared with ω-6 or ω-9-supplemented animals, we observed that late-stage prostate tumor growth was reduced with a monoacylglyceride (MAG)-conjugated form of eicosapentaenoic acid (EPA) supplementation, whereas docosahexanenoic acid (DHA) caused an early reduction. MAG-EPA significantly decreased tumor blood vessel diameter (P < 0.001). RNA sequencing analysis revealed that MAG-EPA downregulated angiogenesis- and vascular-related pathways in tumors. We also observed this tissue vascular phenotype in a clinical trial testing MAG-EPA versus a high oleic sunflower oil placebo. Using anti-CD31 IHC, we observed that MAG-EPA reduced blood vessel diameter in prostate tumor tissue (P = 0.03) but not in normal adjacent tissue. Finally, testing autocrine and paracrine effects in an avascular tumor spheroid growth assay, both exogenous MAG-EPA and endogenous ω3 reduced VEGF secretion and in vitro endothelial cell tube formation and blocked tumor spheroid growth, suggesting that ω3 molecules can directly hinder prostate cancer cell growth. Altogether, our results suggest that fatty acids regulate prostate cancer growth and that a tumor-specific microenvironment is required for the anti-vascular effect of MAG-EPA in patients with prostate cancer. IMPLICATIONS: Increasing the amount of ingested EPA omega-3 subtype for patients with prostate cancer might help to reduce prostate tumor progression by reducing tumor vascularization.

Direct Bioprinting of 3D Multicellular Breast Spheroids onto Endothelial Networks

Bioprinting is emerging as a promising tool to fabricate 3D human cancer models that better recapitulate critical hallmarks of in vivo tissue architecture. In current layer-by-layer extrusion bioprinting, individual cells are extruded in a bioink together with complex spatial and temporal cues to promote hierarchical tissue self-assembly. However, this biofabrication technique relies on complex interactions among cells, bioinks and biochemical and biophysical cues. Thus, self-assembly may take days or even weeks, may require specific bioinks, and may not always occur when there is more than one cell type involved. We therefore developed a technique to directly bioprint pre-formed 3D breast epithelial spheroids in a variety of bioinks. Bioprinted pre-formed 3D breast epithelial spheroids sustained their viability and polarized architecture after printing. We additionally printed the 3D spheroids onto vascular endothelial cell networks to create a co-culture model. Thus, the novel bioprinting technique rapidly creates a more physiologically relevant 3D human breast model at lower cost and with higher flexibility than traditional bioprinting techniques. This versatile bioprinting technique can be extrapolated to create 3D models of other tissues in additional bioinks.

Roles of Proteoglycans and Glycosaminoglycans in Cancer Development and Progression

The extracellular matrix (ECM) spatiotemporally controls cell fate; however, dysregulation of ECM remodeling can lead to tumorigenesis and cancer development by providing favorable conditions for tumor cells. Proteoglycans (PGs) and glycosaminoglycans (GAGs) are the major macromolecules composing ECM. They influence both cell behavior and matrix properties through direct and indirect interactions with various cytokines, growth factors, cell surface receptors, adhesion molecules, enzymes, and glycoproteins within the ECM. The classical features of PGs/GAGs play well-known roles in cancer angiogenesis, proliferation, invasion, and metastasis. Several lines of evidence suggest that PGs/GAGs critically affect broader aspects in cancer initiation and the progression process, including regulation of cell metabolism, serving as a sensor of ECM's mechanical properties, affecting immune supervision, and participating in therapeutic resistance to various forms of treatment. These functions may be implemented through the characteristics of PGs/GAGs as molecular bridges linking ECM and cells in cell-specific and context-specific manners within the tumor microenvironment (TME). In this review, we intend to present a comprehensive illustration of the ways in which PGs/GAGs participate in and regulate several aspects of tumorigenesis; we put forward a perspective regarding their effects as biomarkers or targets for diagnoses and therapeutic interventions.

ECM1 secreted by HER2-overexpressing breast cancer cells promotes formation of a vascular niche accelerating cancer cell migration and invasion

The tumor microenvironment is increasingly recognized as key player in cancer progression. Investigating heterotypic interactions between cancer cells and their microenvironment is important for understanding how specific cell types support cancer. Forming the vasculature, endothelial cells (ECs) are a prominent cell type in the microenvironment of both normal and neoplastic breast gland. Here, we sought out to analyze epithelial-endothelial cross talk in the breast using isogenic non-tumorigenic vs. tumorigenic breast epithelial cell lines and primary ECs. The cellular model used here consists of D492, a breast epithelial cell line with stem cell properties, and two isogenic D492-derived EMT cell lines, D492M and D492HER2. D492M was generated by endothelial-induced EMT and is non-tumorigenic while D492HER2 is tumorigenic, expressing the ErbB2/HER2 oncogene. To investigate cellular cross talk, we used both conditioned medium (CM) and 2D/3D co-culture systems. Secretome analysis of D492 cell lines was performed using mass spectrometry and candidate knockdown (KD), and overexpression (OE) was done using siRNA and CRISPRi/CRISPRa technology. D492HER2 directly enhances endothelial network formation and activates a molecular axis in ECs promoting D492HER2 migration and invasion, suggesting an endothelial feedback response. Secretome analysis identified extracellular matrix protein 1 (ECM1) as potential angiogenic inducer in D492HER2. Confirming its involvement, KD of ECM1 reduced the ability of D492HER2-CM to increase endothelial network formation and induce the endothelial feedback, while recombinant ECM1 (rECM1) increased both. Interestingly, NOTCH1 and NOTCH3 expression was upregulated in ECs upon treatment with D492HER2-CM or rECM1 but not by CM from D492HER2 with ECM1 KD. Blocking endothelial NOTCH signaling inhibited the increase in network formation and the ability of ECs to promote D492HER2 migration and invasion. In summary, our data demonstrate that cancer-secreted ECM1 induces a NOTCH-mediated endothelial feedback promoting cancer progression by enhancing migration and invasion. Targeting this interaction may provide a novel possibility to improve cancer treatment.

Extracellular BMP Antagonists, Multifaceted Orchestrators in the Tumor and Its Microenvironment

The bone morphogenetic proteins (BMPs), a subgroup of the transforming growth factor-β (TGF-β) superfamily, are involved in multiple biological processes such as embryonic development and maintenance of adult tissue homeostasis. The importance of a functional BMP pathway is underlined by various diseases, including cancer, which can arise as a consequence of dysregulated BMP signaling. Mutations in crucial elements of this signaling pathway, such as receptors, have been reported to disrupt BMP signaling. Next to that, aberrant expression of BMP antagonists could also contribute to abrogated signaling. In this review we set out to highlight how BMP antagonists affect not only the cancer cells, but also the other cells present in the microenvironment to influence cancer progression.

Assessing the Current State of Lung Cancer Chemoprevention: A Comprehensive Overview

Chemoprevention of lung cancer is thought to significantly reduce the risk of acquiring these conditions in the subpopulation of patients with underlying health issues, such as chronic obstructive pulmonary disorder and smoking-associated lung problems. Many strategies have been tested in the previous decades, with very few translating to successful clinical trials in specific subpopulations of patients. In this review, we analyze these strategies, as well as new approaches that have emerged throughout the last few years, including synthetic lethality concept and microbiome-induced regulation of lung carcinogenesis. Overall, the continuous effort in the area of lung chemoprevention is required to develop practical therapeutical approaches. Given the inconsistency of results obtained in clinical trials targeting lung cancer chemoprevention in various subgroups of patients that differ in the underlying health condition, race, and gender, we believe that individualized approaches will have more promise than generalized treatments.

Diversity of Organism-Wide and Organ-Specific Endothelial Cells

PURPOSE OF REVIEW

Endothelial cells are of great importance in many types of diseases including the coronary artery diseases in heart and stroke in brain. In this review, we explore the heterogeneity among endothelial cells from an organism-wide, organ-specific, and healthy versus disease perspective.

RECENT FINDINGS

Recent studies addressing the cellular heterogeneity between arterial versus venous endothelial cells (ECs) have revealed that arterial ECs have tighter junctions, a decreased immune response, anticoagulant properties while veins have both anticoagulant and procoagulant properties. Blood and lymphatic ECs are quite distinct from each other as well, with the lymphatic ECs being more involved in the immune response and lymphangiogenesis while blood vessel ECs being involved in angiogenesis and maintenance of perfusion throughout the body. ECs from various organs such as the heart, the lung, and especially the brain are quite heterogeneous and provide barriers that prevent small particles to pass through the endothelium when compared with the endothelium of the liver and the kidney that are quite porous. The heart ECs have higher angiogenesis and metabolic rates (oxidation and glycolysis) than lung, liver, and kidney ECs. Ex vivo liver and kidney ECs grow at a moderate pace, while the lung and brain ECs grow very slowly. ECs from within a tumor have fenestrae and large intracellular gaps and junctions leading to increased permeability and tumor cell overgrowth. There is a large degree of heterogeneity among organism-wide and organ-specific ECs as well as between healthy and disease-specific ECs. We believe this review will help highlight the EC heterogeneity and further advance our ability to treat cardiovascular disease and other conditions.

Cancer Metastasis: The Role of the Extracellular Matrix and the Heparan Sulfate Proteoglycan Perlecan

Cancer metastasis is the dissemination of tumor cells to new sites, resulting in the formation of secondary tumors. This process is complex and is spatially and temporally regulated by intrinsic and extrinsic factors. One important extrinsic factor is the extracellular matrix, the non-cellular component of tissues. Heparan sulfate proteoglycans (HSPGs) are constituents of the extracellular matrix, and through their heparan sulfate chains and protein core, modulate multiple events that occur during the metastatic cascade. This review will provide an overview of the role of the extracellular matrix in the events that occur during cancer metastasis, primarily focusing on perlecan. Perlecan, a basement membrane HSPG is a key component of the vascular extracellular matrix and is commonly associated with events that occur during the metastatic cascade. Its contradictory role in these events will be discussed and we will highlight the recent advances in cancer therapies that target HSPGs and their modifying enzymes.

The Metabolic Remodelling in Lung Cancer and Its Putative Consequence in Therapy Response

Lung cancer is the leading cause of cancer-related deaths worldwide in both men and women. Conventional chemotherapy has failed to provide long-term benefits for many patients and in the past decade, important advances were made to understand the underlying molecular/genetic mechanisms of lung cancer, allowing the unfolding of several other pathological entities. Considering these molecular subtypes, and the appearance of promising targeted therapies, an effective personalized control of the disease has emerged, nonetheless benefiting a small proportion of patients. Although immunotherapy has also appeared as a new hope, it is still not accessible to the majority of patients with lung cancer.The metabolism of energy and biomass is the basis of cellular survival. This is true for normal cells under physiological conditions and it is also true for pathophysiologically altered cells, such as cancer cells. Thus, knowledge of the metabolic remodelling that occurs in cancer cells in the sense of, on one hand, surviving in the microenvironment of the organ in which the tumour develops and, on the other hand, escaping from drugs conditioned microenvironment, is essential to understand the disease and to develop new therapeutic approaches.

Heterogeneity of Vascular Endothelial Cells, De Novo Arteriogenesis and Therapeutic Implications in Pancreatic Neuroendocrine Tumors

Arteriogenesis supplies oxygen and nutrients in the tumor microenvironment (TME), which may play an important role in tumor growth and metastasis. Pancreatic neuroendocrine tumors (pNETs) are the second most common pancreatic malignancy and are frequently metastatic on presentation. Nearly a third of pNETs secrete bioactive substances causing debilitating symptoms. Current treatment options for metastatic pNETs are limited. Importantly, these tumors are highly vascularized and heterogeneous neoplasms, in which the heterogeneity of vascular endothelial cells (ECs) and de novo arteriogenesis may be critical for their progression. Current anti-angiogenetic targeted treatments have not shown substantial clinical benefits, and they are poorly tolerated. This review article describes EC heterogeneity and heterogeneous tumor-associated ECs (TAECs) in the TME and emphasizes the concept of de novo arteriogenesis in the TME. The authors also emphasize the challenges of current antiangiogenic therapy in pNETs and discuss the potential of tumor arteriogenesis as a novel therapeutic target. Finally, the authors prospect the clinical potential of targeting the FoxO1-CD36-Notch pathway that is associated with both pNET progression and arteriogenesis and provide insights into the clinical implications of targeting plasticity of cancer stem cells (CSCs) and vascular niche, particularly the arteriolar niche within the TME in pNETs, which will also provide insights into other types of cancer, including breast cancer, lung cancer, and malignant melanoma.

Active roles of dysfunctional vascular endothelium in fibrosis and cancer

Chronic inflammation is the underlying pathological condition that results in fibrotic diseases. More recently, many forms of cancer have also been linked to chronic tissue inflammation. While stromal immune cells and myofibroblasts have been recognized as major contributors of cytokines and growth factors that foster the formation of fibrotic tissue, the endothelium has traditionally been regarded as a passive player in the pathogenic process, or even as a barrier since it provides a physical divide between the circulating immune cells and the inflamed tissues. Recent findings, however, have indicated that endothelial cells in fact play a crucial role in the inflammatory response. Endothelial cells can be activated by cytokine signaling and express inflammatory markers, which can sustain or exacerbate the inflammatory process. For example, the activated endothelium can recruit and activate leukocytes, thus perpetuating tissue inflammation, while sustained stimulation of endothelial cells may lead to endothelial-to-mesenchymal transition that contributes to fibrosis. Since chronic inflammation has now been recognized as a significant contributing factor to tumorigenesis, it has also emerged that activation of endothelium also occurs in the tumor microenvironment. This review summarizes recent findings characterizing the molecular and cellular changes in the vascular endothelium that contribute to tissue fibrosis, and potentially to cancer formation.

Effect of Ionizing Radiation on Human EA.hy926 Endothelial Cells under Inflammatory Conditions and Their Interactions with A549 Tumour Cells

Purpose

Most tumours are characterized by an inflammatory microenvironment, and correlations between inflammation and cancer progression have been shown. Endothelial cells (ECs), as part of the tumour microenvironment, play a crucial role in inflammatory processes as well as in angiogenesis and could be critical targets of cancer therapy like irradiation. Therefore, in the present study we investigated the effect of ionizing radiation on endothelial cells under inflammatory conditions and their interactions with tumour cells.

Methods

Nonactivated and TNF-α treatment-activated human EC EA.hy926 were irradiated with doses between 0.1 Gy and 6 Gy with a linear accelerator. Using a multiplex assay, the accumulation of various chemokines (IL-8, MCP-1, E-selectin, and P-selectin) and soluble adhesion molecules (sICAM-1 and VCAM-1) as well as protein values of the vascular endothelial growth factor (VEGF) was measured in the supernatant at different time points. The adhesion capability of irradiated and nonirradiated A549 tumour cells to EA.hy926 cells was measured using flow cytometry, and the migration of tumour cells was investigated with a scratch motility assay.

Results

In contrast to unirradiated cells, IR of ECs resulted in a modified release of chemokines IL-8 and MCP-1 as well as the adhesion molecules sICAM-1 and VCAM-1 in the EC, whereas concentrations of E-selectin and P-selectin as well as VEGF were not influenced. IR always affected the adhesion capability of tumour cells to ECs with the effect dependent on the IR-treated cell type. TNF-α treatment generally increased adhesion ability of the tumour cells. Tumour cell migration was clearly inhibited after IR. This inhibitory effect was eliminated for radiation doses from 0.5 to 2 Gy when, additionally, an inflammatory environment was predominant.

Conclusions

Our results support past findings suggesting that ECs, as part of the inflammatory microenvironment of tumours, are important regulators of the actual tumour response to radiation therapy.

Chronic Obstructive Pulmonary Disease and Lung Cancer: Underlying Pathophysiology and New Therapeutic Modalities

Chronic obstructive pulmonary disease (COPD) and lung cancer are major lung diseases affecting millions worldwide. Both diseases have links to cigarette smoking and exert a considerable societal burden. People suffering from COPD are at higher risk of developing lung cancer than those without, and are more susceptible to poor outcomes after diagnosis and treatment. Lung cancer and COPD are closely associated, possibly sharing common traits such as an underlying genetic predisposition, epithelial and endothelial cell plasticity, dysfunctional inflammatory mechanisms including the deposition of excessive extracellular matrix, angiogenesis, susceptibility to DNA damage and cellular mutagenesis. In fact, COPD could be the driving factor for lung cancer, providing a conducive environment that propagates its evolution. In the early stages of smoking, body defences provide a combative immune/oxidative response and DNA repair mechanisms are likely to subdue these changes to a certain extent; however, in patients with COPD with lung cancer the consequences could be devastating, potentially contributing to slower postoperative recovery after lung resection and increased resistance to radiotherapy and chemotherapy. Vital to the development of new-targeted therapies is an in-depth understanding of various molecular mechanisms that are associated with both pathologies. In this comprehensive review, we provide a detailed overview of possible underlying factors that link COPD and lung cancer, and current therapeutic advances from both human and preclinical animal models that can effectively mitigate this unholy relationship.

Bioinspired lipoproteins-mediated photothermia remodels tumor stroma to improve cancer cell accessibility of second nanoparticles

The tumor stromal microenvironments (TSM) including stromal cells and extracellular matrix (ECM) form an abominable barrier hampering nanoparticles accessibility to cancer cells, significantly compromising their antitumor effects. Herein, we report a bioinspired lipoprotein (bLP) that can induce efficient photothermia to remodel TSM and improve second bLP accessibility to cancer cells for antitumor therapy. The multiple stromal cells and ECM components in TSM are remarkably disrupted by bLP-mediated photothermal effects, which cause a 4.27-fold enhancement of second bLP accumulation in tumor, deep penetration in whole tumor mass and 27.0-fold increase of accessibility to cancer cells. Of note, this bLP-mediated TSM-remodeling to enhance cancer cell accessibility (TECA) strategy produces an eminent suppression of tumor growth and results in a 97.4% inhibition of lung metastasis, which is superior to the counterpart liposomes. The bLP-mediated TECA strategy provides deeper insights into enhancing nanoparticle accessibility to cancer cells for antitumor therapy.

The stromal cells and extracellular matrix hamper nanoparticle access to cancer cells and their anti-cancer efficacy. Here, the authors report a bioinspired lipoprotein (bLP) for photothermal remodelling of tumour stroma and show this to improve subsequent bLP accessibility to cancer cells.

Dihydrodiosgenin inhibits endothelial cell-derived factor VIII and platelet-mediated hepatocellular carcinoma metastasis

Background: Our previous studies have demonstrated that diosgenin and diosgenin derivatives exhibit excellent antithrombotic activity via regulating platelet function and coagulation factor level. Platelets and blood coagulation system are highly associated with tumor hematogenous metastasis. Therefore, the purpose of this study was to evaluate whether dihydrodiosgenin (dydio) mediated-platelet inhibition or coagulation factor level modulation is involved in hepatocellular carcinoma cell (HCC) metastasis. Methods: Cell viability was examined by MTT and colony formation assays. Platelet aggregation text and morphology were used to assess dydio's role on tumor cell-induced platelet activation (TCIPA). Scratch assay, adhesion assay and Western blot were used to evaluate dydio's role on platelet-mediated metastasis. Western blot and fluorescence detection were performed to clarify dydio's role on endothelial cell (EC) function. The mice lung metastasis model was constructed to investigated dydio's function on coagulation factor and platelet-mediated metastasis. Results: This study found that pretreatment with dydio caused a significant inhibition of TCIPA. Platelets exposed to dydio significantly inhibited their adhesion to tumor cells, meanwhile, releasates of platelets that pretreated with dydio led to diminished cancer cell proliferation and migration along with the increase of epithelial markers E-cadherin and loss of mesenchymal phenotype. Additionally, ECs pretreated with dydio suppressed factor VIII (FVIII) level which in turn restrained the activation of platelets and the adhesion of cancer cells or platelets to ECs. Interestingly, our study demonstrated that FVIII could promote HCC proliferation. In vivo study revealed that mice intragastrical (i.g.) administration with dydio significantly inhibited the lung metastasis of hepal-6 cells which is highly correlated with the altered platelet function and coagulation level. Conclusion: Taken together, these results demonstrated that dydio altered platelet function and coagulation FVIII level, resulting in decreased metastatic potential of HCC. Thus, our study reveals that dydio exerts novel mechanisms of antitumor action beside its direct antitumor activity.

Cancer-associated fibroblasts contribute to cisplatin resistance by modulating ANXA3 in lung cancer cells

Cancer tissues consist of cancer cells, surrounding stromal cells and the extracellular matrix. Cancer‐associated fibroblasts (CAF) are one of the key components of stromal cells. CAF have a great impact on the behavior of cancer cells, including proliferation, invasion, metastasis and chemoresistance in many ways. However, the underlying mechanism had not been fully elucidated. In this study, we investigated the role of CAF in cisplatin resistance of lung cancer cells. By using conditioned medium from CAF (CAF‐CM), we found that CAF decreased the sensitivity of lung cancer cells to cisplatin. RNA sequencing results showed that CAF expressed a higher level of Annexin A3 (ANXA3) than normal fibroblasts (NF), and CAF‐CM incubation increased the ANXA3 level in lung cancer cells. Overexpression of ANXA3 in lung cancer cells increased cisplatin resistance and activated c‐jun N‐terminal kinase (JNK), whereas knockdown of ANXA3 increased cisplatin sensitivity. Further study showed that CAF‐CM enhanced cisplatin resistance by inhibiting cisplatin‐induced apoptosis, determined by repression of caspase‐3 and caspase‐8, through activation of the ANXA3/JNK pathway. Conversely, suppression of JNK activation by specific inhibitor retarded the effect of CAF‐CM and ANXA3 on cisplatin sensitivity. Taken together, our study demonstrated that CAF potentiated chemoresistance of lung cancer cells through a novel ANXA3/JNK pathway both in vitro and in vivo, suggesting ANXA3 could be a potential therapeutic target for the treatment of chemoresistant cancer.

Endothelial cell-derived nidogen-1 inhibits migration of SK-BR-3 breast cancer cells

BACKGROUND

The tumour microenvironment is a critical regulator of malignant cancer progression. While endothelial cells have been widely studied in the context of tumour angiogenesis, their role as modulators of cancer cell invasion and migration is poorly understood.

METHODS

We have investigated the influence of endothelial cells on the invasive and migratory behaviour of human cancer cells in vitro.

RESULTS

Upon exposure to culture supernatants of endothelial cells, distinct cancer cells, such as SK-BR-3 cells, showed significantly increased invasion and cell migration concomitant with changes in cell morphology and gene expression reminiscent of an epithelial-mesenchymal transition (EMT). Interestingly, the pro-migratory effect on SK-BR-3 cells was significantly enhanced by supernatants obtained from subconfluent, proliferative endothelial cells rather than from confluent, quiescent endothelial cells. Systematically comparing the supernatants of subconfluent and confluent endothelial cells by quantitative MS proteomics revealed eight candidate proteins that were secreted at significantly higher levels by confluent endothelial cells representing potential inhibitors of cancer cell migration. Among these proteins, nidogen-1 was exclusively expressed in confluent endothelial cells and was found to be necessary and sufficient for the inhibition of SK-BR-3 cell migration. Indeed, SK-BR-3 cells exposed to nidogen-1-depleted endothelial supernatants showed increased promigratory STAT3 phosphorylation along with increased cell migration. This reflects the situation of enhanced SK-BR-3 migration upon stimulation with conditioned medium from subconfluent endothelial cells with inherent absence of nidogen-1 expression.

CONCLUSION

The identification of nidogen-1 as an endothelial-derived inhibitor of migration of distinct cancer cell types reveals a novel mechanism of endothelial control over cancer progression.