Dual angiopoietin-2 and VEGFA inhibition elicits antitumor immunity that is enhanced by PD-1 checkpoint blockade

A landscape of checkpoint blockade resistance in cancer: underlying mechanisms and current strategies to overcome resistance

The discovery of immune checkpoints and the development of immune checkpoint inhibitors (ICI) have achieved a durable response in advanced-stage cancer patients. However, there is still a high proportion of patients who do not benefit from ICI therapy due to a lack of response when first treated (primary resistance) or detection of disease progression months after objective response is observed (acquired resistance). Here, we review the current FDA-approved ICI for the treatment of certain solid malignancies, evaluate the contrasting responses to checkpoint blockade in different cancer types, explore the known mechanisms associated with checkpoint blockade resistance (CBR), and assess current strategies in the field that seek to overcome these mechanisms. In order to improve current therapies and develop new ones, the immunotherapy field still has an unmet need in identifying other molecules that act as immune checkpoints, and uncovering other mechanisms that promote CBR.

CD74+ fibroblasts proliferate upon mechanical stretching to promote angiogenesis in keloids

The healing of human skin wounds is susceptible to perturbation caused by excessive mechanical stretching, resulting in enlarged scars, hypertrophic scars, or even keloids in predisposed individuals. Keloids are fibro-proliferative scar tissues that extend beyond the initial wound boundary, consisting of the actively progressing periphery and the quiescent center. The stretch-associated outgrowth and enhanced angiogenesis are two features of the periphery of keloids. However, which cell population is responsible for transducing the mechanical stimulation to the progression of keloids remains unclear. Herein, through integrative analysis of single-cell RNA sequencing of keloids, we identified CD74+ fibroblasts, a previously unappreciated subset of fibroblasts with pro-angiogenic and stretch-induced proliferative capacities, as a key player in stretch-induced progression of keloids. Immunostaining of keloid cryosections depicted a predominant distribution of CD74+ fibroblasts in the periphery, interacting with the vasculature. In vitro tube formation assays on purified CD74+ fibroblasts ascertained their pro-angiogenic function. BrdU assays revealed that these cells proliferate upon stretching, through PIEZO1-mediated calcium influx and the downstream ERK and AKT signaling. Collectively, our findings propose a model wherein CD74+ fibroblasts serve as pivotal drivers of stretch-induced keloid progression, fueled by their proliferative and pro-angiogenic activities. Targeting the attributes of CD74+ fibroblasts holds promise as a therapeutic strategy for the management of keloids.

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.

The crossroad between tumor and endothelial cells

Endothelial cells are critical in tumor development, and the specific targeting of endothelial cells offers a potent means to effectively impede angiogenesis and suppress the growth of tumors. Tumor endothelial cells are responsible for the loss of anticancer immunity, the so-called endothelial anergy, i.e., the unresponsiveness of tumor endothelial cells to pro-inflammatory stimulation, not allowing adhesion of immune cells to the endothelium. Endothelial cells downregulate antigen presentation and recruitment of immune cells, contributing to immunosuppression. Targeting endothelial cells may assist in improving the immune effect of immune cells in tumor microenvironment.

Pre-metastatic niche: formation, characteristics and therapeutic implication

Distant metastasis is a primary cause of mortality and contributes to poor surgical outcomes in cancer patients. Before the development of organ-specific metastasis, the formation of a pre-metastatic niche is pivotal in promoting the spread of cancer cells. This review delves into the intricate landscape of the pre-metastatic niche, focusing on the roles of tumor-derived secreted factors, extracellular vesicles, and circulating tumor cells in shaping the metastatic niche. The discussion encompasses cellular elements such as macrophages, neutrophils, bone marrow-derived suppressive cells, and T/B cells, in addition to molecular factors like secreted substances from tumors and extracellular vesicles, within the framework of pre-metastatic niche formation. Insights into the temporal mechanisms of pre-metastatic niche formation such as epithelial-mesenchymal transition, immunosuppression, extracellular matrix remodeling, metabolic reprogramming, vascular permeability and angiogenesis are provided. Furthermore, the landscape of pre-metastatic niche in different metastatic organs like lymph nodes, lungs, liver, brain, and bones is elucidated. Therapeutic approaches targeting the cellular and molecular components of pre-metastatic niche, as well as interventions targeting signaling pathways such as the TGF-β, VEGF, and MET pathways, are highlighted. This review aims to enhance our understanding of pre-metastatic niche dynamics and provide insights for developing effective therapeutic strategies to combat tumor metastasis.

Improving tumor microenvironment assessment in chip systems through next-generation technology integration

The tumor microenvironment (TME) comprises a diverse array of cells, both cancerous and non-cancerous, including stromal cells and immune cells. Complex interactions among these cells play a central role in driving cancer progression, impacting critical aspects such as tumor initiation, growth, invasion, response to therapy, and the development of drug resistance. While targeting the TME has emerged as a promising therapeutic strategy, there is a critical need for innovative approaches that accurately replicate its complex cellular and non-cellular interactions; the goal being to develop targeted, personalized therapies that can effectively elicit anti-cancer responses in patients. Microfluidic systems present notable advantages over conventional in vitro 2D co-culture models and in vivo animal models, as they more accurately mimic crucial features of the TME and enable precise, controlled examination of the dynamic interactions among multiple human cell types at any time point. Combining these models with next-generation technologies, such as bioprinting, single cell sequencing and real-time biosensing, is a crucial next step in the advancement of microfluidic models. This review aims to emphasize the importance of this integrated approach to further our understanding of the TME by showcasing current microfluidic model systems that integrate next-generation technologies to dissect cellular intra-tumoral interactions across different tumor types. Carefully unraveling the complexity of the TME by leveraging next generation technologies will be pivotal for developing targeted therapies that can effectively enhance robust anti-tumoral responses in patients and address the limitations of current treatment modalities.

Towards Targeting Endothelial Rap1B to Overcome Vascular Immunosuppression in Cancer

The vascular endothelium, a specialized monolayer of endothelial cells (ECs), is crucial for maintaining vascular homeostasis by controlling the passage of substances and cells. In the tumor microenvironment, Vascular Endothelial Growth Factor A (VEGF-A) drives tumor angiogenesis, leading to endothelial anergy and vascular immunosuppression-a state where ECs resist cytotoxic CD8+ T cell infiltration, hindering immune surveillance. Immunotherapies have shown clinical promise. However, their effectiveness is significantly reduced by tumor EC anergy. Anti-angiogenic treatments aim to normalize tumor vessels and improve immune cell infiltration. Despite their potential, these therapies often cause significant systemic toxicities, necessitating new treatments. The small GTPase Rap1B emerges as a critical regulator of Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) signaling in ECs. Our studies using EC-specific Rap1B knockout mice show that the absence of Rap1B impairs tumor growth, alters vessel morphology, and increases CD8+ T cell infiltration and activation. This indicates that Rap1B mediates VEGF-A's immunosuppressive effects, making it a promising target for overcoming vascular immunosuppression in cancer. Rap1B shares structural and functional similarities with RAS oncogenes. We propose that targeting Rap1B could enhance therapies' efficacy while minimizing adverse effects by reversing endothelial anergy. We briefly discuss strategies successfully developed for targeting RAS as a model for developing anti-Rap1 therapies.

Immune microenvironment in papillary thyroid carcinoma: roles of immune cells and checkpoints in disease progression and therapeutic implications

Papillary thyroid cancer (PTC) is the most common type of primary thyroid cancer. Despite the low malignancy and relatively good prognosis, some PTC cases are highly aggressive and even develop refractory cancer in the thyroid. Growing evidence suggested that microenvironment in tumor affected PTC biological behavior due to different immune states. Different interconnected components in the immune system influence and participate in tumor invasion, and are closely related to PTC metastasis. Immune cells and molecules are widely distributed in PTC tissues. Their quantity and proportion vary with the host's immune status, which suggests that immunotherapy may be a very promising therapeutic modality for PTC. In this paper, we review the role of immune cells and immune checkpoints in PTC immune microenvironment based on the characteristics of the PTC tumor microenvironment.

Anlotinib and anti-PD-1 mAbs perfected CIK cell therapy for lung adenocarcinoma in preclinical trials

Murine cytokine-induced killer (CIK) cells are heterologous cells that kill various allogeneic and isogenic tumors and have functional and phenotypic characteristics of natural killer cells and T lymphocytes. However, the effect of CIK cells alone on solid tumor therapy is only limited. To enhance the therapeutic effect, it is vital to discover a mix of several therapy approaches. Immune cell function is inhibited by abnormal tumor vessels and the tumor microenvironment, which block lymphocyte entry into tumor tissue. To increase the effectiveness of CIK cells' antitumor activity, antivascular therapy and CIK cell therapy can be combined. Furthermore, anlotinib is a tiny drug with multitarget tyrosine kinase inhibitors that can block cell migration, delay angiogenesis, and decrease blood vessel density. Compared with other antiangiogenesis drugs, anlotinib stands out due to the wider target of action and lower effective dose. In this work, anlotinib and murine CIK cells were coupled to boost CD3+ T cell infiltration, CD3+CD4+ T cell infiltration, and expression of granzyme B and interferon γ from CD3+CD8+ T cells, which increased the antitumor activity. Through the generation of cytotoxic cytokines by T lymphocytes, the therapeutic group using anti-PD-1 monoclonal antibodies in conjunction with anlotinib and CIK cells was more successful than the group receiving dual therapy. The preclinical study contributes to exploring the therapeutic alternatives for patients with lung adenocarcinoma, thus prolonging their lives.

ZBTB46 coordinates angiogenesis and immunity to control tumor outcome

Tumor angiogenesis and immunity show an inverse correlation in cancer progression and outcome1. Here, we report that ZBTB46, a repressive transcription factor and a widely accepted marker for classical dendritic cells (DCs)2,3, controls both tumor angiogenesis and immunity. Zbtb46 was downregulated in both DCs and endothelial cells by tumor-derived factors to facilitate robust tumor growth. Zbtb46 downregulation led to a hallmark pro-tumor microenvironment (TME), including dysfunctional vasculature and immunosuppressive conditions. Analysis of human cancer data revealed a similar association of low ZBTB46 expression with an immunosuppressive TME and a worse prognosis. In contrast, enforced Zbtb46 expression led to TME changes to restrict tumor growth. Mechanistically, Zbtb46-deficient endothelial cells were highly angiogenic, and Zbtb46-deficient bone marrow progenitors upregulated Cebpb and diverted the DC program to immunosuppressive myeloid lineage output, potentially explaining the myeloid lineage skewing phenomenon in cancer4. Conversely, enforced Zbtb46 expression normalized tumor vessels and, by suppressing Cebpb, skewed bone marrow precursors toward immunostimulatory myeloid lineage output, leading to an immune-hot TME. Remarkably, Zbtb46 mRNA treatment synergized with anti-PD1 immunotherapy to improve tumor management in preclinical models. These findings identify ZBTB46 as a critical factor for angiogenesis and for myeloid lineage skewing in cancer and suggest that maintaining its expression could have therapeutic benefits.

Mechanisms of resistance to tyrosine kinase inhibitor-targeted therapy and overcoming strategies

Tyrosine kinase inhibitor (TKI)-targeted therapy has revolutionized cancer treatment by selectively blocking specific signaling pathways crucial for tumor growth, offering improved outcomes with fewer side effects compared with conventional chemotherapy. However, despite their initial effectiveness, resistance to TKIs remains a significant challenge in clinical practice. Understanding the mechanisms underlying TKI resistance is paramount for improving patient outcomes and developing more effective treatment strategies. In this review, we explored various mechanisms contributing to TKI resistance, including on-target mechanisms and off-target mechanisms, as well as changes in the tumor histology and tumor microenvironment (intrinsic mechanisms). Additionally, we summarized current therapeutic approaches aiming at circumventing TKI resistance, including the development of next-generation TKIs and combination therapies. We also discussed emerging strategies such as the use of dual-targeted antibodies and PROteolysis Targeting Chimeras. Furthermore, we explored future directions in TKI-targeted therapy, including the methods for detecting and monitoring drug resistance during treatment, identification of novel targets, exploration of dual-acting kinase inhibitors, application of nanotechnologies in targeted therapy, and so on. Overall, this review provides a comprehensive overview of the challenges and opportunities in TKI-targeted therapy, aiming to advance our understanding of resistance mechanisms and guide the development of more effective therapeutic approaches in cancer treatment.

Immune checkpoint inhibitors targeting PD-1/PD-L1 in the treatment of human lymphomas

Non-Hodgkin lymphomas (NHLs) encompass a diverse group of malignancies arising from B cells, T cells, and natural killer (NK) cells at various stages of differentiation. Conversely, classical Hodgkin lymphomas (cHLs) primarily feature Reed-Sternberg cells (RSCs) amid a background of reactive immune cells. Immunomodulatory pathways, notably the PD-1/PD-L1 axis, play pivotal roles in tumor immune evasion across both NHLs and cHLs. Elevated expression of PD-1 and PD-L1 is observed in a spectrum of lymphomas, influencing prognosis and treatment response. Therapeutically, immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 have revolutionized lymphoma management, particularly in relapsed/refractory cases. Nivolumab and pembrolizumab, among others, have demonstrated efficacy in various B-cell lymphomas, with promising outcomes in cHL. Combination strategies incorporating ICIs with conventional chemotherapy or targeted agents show enhanced efficacy and are being explored extensively. In this review we discuss the most important features of the tumor microenvironment of NHLs and cHLs, address the therapeutic approaches with ICIs and try to outline future perspectives.

Transmural Flow Upregulates PD-L1 Expression in Microvascular Networks

Endothelial programmed death-ligand 1 (PD-L1) expression is higher in tumors than in normal tissues. Also, tumoral vasculatures tend to be leakier than normal vessels leading to a higher trans-endothelial or transmural fluid flow. However, it is not clear whether such elevated transmural flow can control endothelial PD-L1 expression. Here, a new microfluidic device is developed to investigate the relationship between transmural flow and PD-L1 expression in microvascular networks (MVNs). After treating the MVNs with transmural flow for 24 h, the expression of PD-L1 in endothelial cells is upregulated. Additionally, CD8 T cell activation by phytohemagglutinin (PHA) is suppressed when cultured in the MVNs pre-conditioned with transmural flow. Moreover, transmural flow is able to further increase PD-L1 expression in the vessels formed in the tumor microenvironment. Finally, by utilizing blocking antibodies and knock-out assays, it is found that transmural flow-driven PD-L1 upregulation is controlled by integrin αVβ3. Overall, this study provides a new biophysical explanation for high PD-L1 expression in tumoral vasculatures.

Thetumor microenvironment'sinpancreatic cancer:Effects onimmunotherapy successandnovel strategiestoovercomethehostile environment

Cancer is a significant global health issue that poses a considerable burden on both patients and healthcare systems. Many different types of cancers exist that often require unique treatment approaches and therapies. A hallmark of tumor progression is the creation of an immunosuppressive environment, which poses complex challenges for current treatments. Amongst the most explored characteristics is a hypoxic environment, high interstitial pressure, and immunosuppressive cells and cytokines. Traditional cancer treatments involve radiotherapy, chemotherapy, and surgical procedures. The advent of immunotherapies was regarded as a promising approach with hopes of greatly increasing patients' survival and outcome. Although some success is seen with various immunotherapies, the vast majority of monotherapies are unsuccessful. This review examines how various aspects of the tumor microenvironment (TME) present challenges that impede the success of immunotherapies. Subsequently, we review strategies to manipulate the TME to facilitate the success of immunotherapies.

Incorporation of immunotherapies and nanomedicine to better normalize angiogenesis-based cancer treatment

Neoadjuvant targeting of tumor angiogenesis has been developed and approved for the treatment of malignant tumors. However, vascular disruption leads to tumor hypoxia, which exacerbates the treatment process and causes drug resistance. In addition, successful delivery of therapeutic agents and efficacy of radiotherapy require normal vascular networks and sufficient oxygen, which complete tumor vasculopathy hinders their efficacy. In view of this controversy, an optimal dose of FDA-approved anti-angiogenic agents and combination with other therapies, such as immunotherapy and the use of nanocarrier-mediated targeted therapy, could improve therapeutic regimens, reduce the need for administration of high doses of chemotherapeutic agents and subsequently reduce side effects. Here, we review the mechanism of anti-angiogenic agents, highlight the challenges of existing therapies, and present how the combination of immunotherapies and nanomedicine could improve angiogenesis-based tumor treatment.

Exploring potential predictive biomarkers through historical perspectives on the evolution of systemic therapies into the emergence of neoadjuvant therapy for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), a type of liver cancer, ranks as the sixth most prevalent cancer globally and represents the third leading cause of cancer-related deaths. Approximately half of HCC patients miss the opportunity for curative treatment and are then limited to undergoing systemic therapies. Currently, systemic therapy has entered the era of immunotherapy, particularly with the advent of immune-checkpoint inhibitors (ICIs), which have significantly enhanced outcomes for patients with advanced HCC. Neoadjuvant treatment for HCC has become a possibility-findings from the IMbrave 050 trial indicated that ICIs offer the benefit of recurrence-free survival for high-risk HCC patients post-resection or local ablation. However, only a small fraction of individuals benefit from systemic therapy. Consequently, there is an urgent need to identify predictive biomarkers for treatment response and outcome assessment. This study reviewed the historical progression of systemic therapy for HCC, highlighting notable therapeutic advancements. This study examined the development of systemic therapies involving conventional drugs and clinical trials utilized in HCC treatment, as well as potential predictive biomarkers for advanced and/or locally advanced HCC. Various studies have revealed potential biomarkers in the context of HCC treatment. These include the association of dendritic cells (DCs) with a favorable response to neoadjuvant therapy, the presence of enriched T effector cells and tertiary lymphoid structures, the identification of CD138+ plasma cells, and distinct spatial arrangements of B cells in close proximity to T cells among responders with locally advanced HCC receiving neoadjuvant cabozantinib and nivolumab treatment. Furthermore, pathological response has been associated with intratumoral cellular triads consisting of progenitor CD8+ T cells and CXCL13+ CD4+ T helper cells surrounding mature DCs in patients receiving neoadjuvant cemiplimab for resectable HCC. Despite no widely recognized predictive biomarkers for HCC individualized treatment, we believe neoadjuvant trials hold the most promise in identifying and validating them. This is because they can collect multiple samples from resectable HCC patients across stages, especially with multi-omics, bridging preclinical and clinical gaps.

Mechanisms, combination therapy, and biomarkers in cancer immunotherapy resistance

Anti-programmed death 1/programmed death ligand 1 (anti-PD-1/PD-L1) antibodies exert significant antitumor effects by overcoming tumor cell immune evasion and reversing T-cell exhaustion. However, the emergence of drug resistance causes most patients to respond poorly to these immune checkpoint inhibitors (ICIs). Studies have shown that insufficient T-cell infiltration, lack of PD-1 expression, deficient interferon signaling, loss of tumor antigen presentation, and abnormal lipid metabolism are all considered to be closely associated with immunotherapy resistance. To address drug resistance in tumor immunotherapy, a lot of research has concentrated on developing combination therapy strategies. Currently, ICIs such as anti-PD-1 /PD-L1 antibody combined with chemotherapy and targeted therapy have been approved for clinical treatment. In this review, we analyze the mechanisms of resistance to anti-PD-1/PD-L1 therapy in terms of the tumor microenvironment, gut microbiota, epigenetic regulation, and co-inhibitory immune checkpoint receptors. We also discuss various promising combination therapeutic strategies to address resistance to anti-PD-1/PD-L1 drugs, including combining these therapies with traditional Chinese medicine, non-coding RNAs, targeted therapy, other ICIs, and personalized cancer vaccines. Moreover, we focus on biomarkers that predict resistance to anti-PD-1/PD-L1 therapy as well as combination therapy efficacy. Finally, we suggest ways to further expand the application of immunotherapy through personalized combination strategies using biomarker systems.

Bioinformatics Analysis and Experimental Verification Define Different Angiogenesis Subtypes in Endometrial Carcinoma and Identify a Prognostic Signature

Increasing evidence indicates that peripheral blood vessels play a pivotal role in regulating tumor growth with the presence of new blood vessels facilitating tumor growth and metastasis. Nevertheless, the impact of specific molecule-mediated angiogenesis on the tumor immune microenvironment (TIME) and individual prognosis of uterine corpus endometrial carcinoma (UCEC) remains uncertain. The transcriptome information on 217 prognostic angiogenesis-related genes was integrated, and the angiogenesis patterns of 506 UCEC patients in The Cancer Genome Atlas (TCGA) cohort were comprehensively evaluated. We identified five angiogenic subtypes, namely, EC1, EC2, EC3, EC4, and EC5, which differed significantly in terms of prognosis, clinicopathological features, cancer hallmarks, genomic mutations, TIME patterns, and immunotherapy responses. Additionally, an angiogenesis-related prognostic risk score (APRS) was constructed to enable an individualized comprehensive evaluation. In multiple cohorts, APRS demonstrated a powerful predictive ability for the prognosis of UCEC patients. Likewise, APRS was confirmed to be associated with clinicopathological features, genomic mutations, cancer hallmarks, and TIME patterns in UCEC patients. The predictability of APRS for immune checkpoint inhibitor (ICI) therapy was also salient. Subsequently, the expression levels of four angiogenesis-related hub genes were verified by qRT-PCR, immunohistochemistry, and single-cell sequencing data analysis. The effects of four representative genes on angiogenesis were validated by Wound-Healing and Transwell assays, tube formation assay in vitro, and tumor xenograft model in vivo. This study proffered a new classification of UCEC patients based on angiogenesis. The established APRS may contribute to individualized prognosis prediction and immunotherapy selections that are better suited for UCEC patients.

Antiangiogenic-immune-checkpoint inhibitor combinations: lessons from phase III clinical trials

Antiangiogenic agents, generally antibodies or tyrosine-kinase inhibitors that target the VEGF-VEGFR pathway, are currently among the few combination partners clinically proven to improve the efficacy of immune-checkpoint inhibitors (ICIs). This benefit has been demonstrated in pivotal phase III trials across different cancer types, some with practice-changing results; however, numerous phase III trials have also had negative results. The rationale for using antiangiogenic drugs as partners for ICIs relies primarily on blocking the multiple immunosuppressive effects of VEGF and inducing several different vascular-modulating effects that can stimulate immunity, such as vascular normalization leading to increased intratumoural blood perfusion and flow, and inhibition of pro-apoptotic effects of endothelial cells on T cells, among others. Conversely, VEGF blockade can also cause changes that suppress antitumour immunity, such as increased tumour hypoxia, and reduced intratumoural ingress of co-administered ICIs. As a result, the net clinical benefits from antiangiogenic-ICI combinations will be determined by the balance between the opposing effects of VEGF signalling and its inhibition on the antitumour immune response. In this Perspective, we summarize the results from the currently completed phase III trials evaluating antiangiogenic agent-ICI combinations. We also discuss strategies to improve the efficacy of these combinations, focusing on aspects that include the deleterious functions of VEGF-VEGFR inhibition on antitumour immunity, vessel co-option as a driver of non-angiogenic tumour growth, clinical trial design, or the rationale for drug selection, dosing and scheduling.

Milestones in tumor vascularization and its therapeutic targeting

Research into the mechanisms and manifestations of solid tumor vascularization was launched more than 50 years ago with the proposition and experimental demonstrations that angiogenesis is instrumental for tumor growth and was, therefore, a promising therapeutic target. The biological knowledge and therapeutic insights forthcoming have been remarkable, punctuated by new concepts, many of which were not foreseen in the early decades. This article presents a perspective on tumor vascularization and its therapeutic targeting but does not portray a historical timeline. Rather, we highlight eight conceptual milestones, integrating initial discoveries and recent progress and posing open questions for the future.

Blocking the angiopoietin-2-dependent integrin β-1 signaling axis abrogates small cell lung cancer invasion and metastasis

Small cell lung cancer (SCLC) is the most aggressive lung cancer entity with an extremely limited therapeutic outcome. Most patients are diagnosed at an extensive stage. However, the molecular mechanisms driving SCLC invasion and metastasis remain largely elusive. We used an autochthonous SCLC mouse model and matched samples from patients with primary and metastatic SCLC to investigate the molecular characteristics of tumor metastasis. We demonstrate that tumor cell invasion and liver metastasis in SCLC are triggered by an Angiopoietin-2 (ANG-2)/Integrin β-1-dependent pathway in tumor cells, mediated by focal adhesion kinase/Src kinase signaling. Strikingly, CRISPR-Cas9 KO of Integrin β-1 or blocking Integrin β-1 signaling by an anti-ANG-2 treatment abrogates liver metastasis formation in vivo. Interestingly, analysis of a unique collection of matched samples from patients with primary and metastatic SCLC confirmed a strong increase of Integrin β-1 in liver metastasis in comparison with the primary tumor. We further show that ANG-2 blockade combined with PD-1-targeted by anti-PD-1 treatment displays synergistic treatment effects in SCLC. Together, our data demonstrate a fundamental role of ANG-2/Integrin β-1 signaling in SCLC cells for tumor cell invasion and liver metastasis and provide a potentially new effective treatment strategy for patients with SCLC.

LEAP-014: first-line lenvatinib + pembrolizumab + chemotherapy in advanced/metastatic esophageal squamous cell carcinoma

Treatment options for patients with advanced or metastatic esophageal squamous cell carcinoma (ESCC) are improving. Current guidelines recommend first-line pembrolizumab plus chemotherapy for patients with unresectable or metastatic ESCC, which has led to improvements in survival outcomes. Antiangiogenic therapy combined with immune checkpoint inhibitors can act synergistically to convert the immunosuppressive tumor microenvironment to an immune supportive microenvironment, thus enhancing antitumor immune responses. In preclinical models, the antiangiogenic agent lenvatinib combined with an anti-PD-1 agent showed synergistic antitumor activity. We describe the design and rationale for the randomized, open-label, phase III LEAP-014 study of lenvatinib in combination with pembrolizumab plus chemotherapy in patients with advanced or metastatic ESCC. Overall survival and progression-free survival are the dual primary end points.Clinical Trial Registration: NCT04949256 (ClinicalTrials.gov).

A bibliometric analysis of the research landscape on vascular normalization in cancer

Tumor vascular normalization profoundly affects the advancement of cancer therapy. Currently, with the rapid increase in research on tumor vascular normalization, few analytical and descriptive studies have investigated the trends in its development, key research power, present research hotspots, and future outlooks. In this study, articles and reviews published between January 1, 2003, and October 29, 2022 were retrieved from Web of Science database. Subsequently, published research trends, countries/regions, institutions, authors, journals, references, and keywords were analyzed based on traditional bibliometric laws (such as Price's exponential growth, Bradford's, Lotka's, and Zipf's). Our results showed that the last two decades have seen an increase in tumor vascular normalization research. USA emerged as the preeminent contributor to the field, boasting the highest H-index and accruing the greatest quantity of publications and citations. Among institutions, Massachusetts General Hospital and Harvard University made significant contributions, and Professor RK Jain was identified as a key leader in this field. Out of 583 academic journals, Cancer Research and Clinical Cancer Research published the most articles on vascular normalization. The research focal points in the field primarily include immunotherapy, tumor microenvironments, nanomedicine, and emerging frontier themes such as metabolism and mechanomedicine. Concurrently, the challenges of vascular normalization in cancer are discussed as well. In conclusion, the study presented a thorough analysis of the literature covering the past 20 years on vascular normalization in cancer, highlighting leading countries, institutions, authors, journals, and the emerging research focal points in this field. Future studies will advance the ongoing efforts in the field of tumor vascular normalization, aiming to enhance our ability to effectively manage and treat cancer.

Combined anti-PD-1, HDAC inhibitor and anti-VEGF for MSS/pMMR colorectal cancer: a randomized phase 2 trial

Epigenetic modifications of chromatin, including histone acetylation, and tumor angiogenesis play pivotal roles in creating an immunosuppressive tumor microenvironment. In the randomized phase 2 CAPability-01 trial, we investigated the potential efficacy of combining the programmed cell death protein-1 (PD-1) monoclonal antibody sintilimab with the histone deacetylase inhibitor (HDACi) chidamide with or without the anti-vascular endothelial growth factor (VEGF) monoclonal antibody bevacizumab in patients with unresectable chemotherapy-refractory locally advanced or metastatic microsatellite stable/proficient mismatch repair (MSS/pMMR) colorectal cancer. Forty-eight patients were randomly assigned to either the doublet arm (sintilimab and chidamide, n = 23) or the triplet arm (sintilimab, chidamide and bevacizumab, n = 25). The primary endpoint of progression-free survival (PFS) rate at 18 weeks (18wPFS rate) was met with a rate of 43.8% (21 of 48) for the entire study population. Secondary endpoint results include a median PFS of 3.7 months, an overall response rate of 29.2% (14 of 48), a disease control rate of 56.3% (27 of 48) and a median duration of response of 12.0 months. The secondary endpoint of median overall survival time was not mature. The triplet arm exhibited significantly improved outcomes compared to the doublet arm, with a greater 18wPFS rate (64.0% versus 21.7%, P = 0.003), higher overall response rate (44.0% versus 13.0%, P = 0.027) and longer median PFS rate (7.3 months versus 1.5 months, P = 0.006). The most common treatment-emergent adverse events observed in both the triplet and doublet arms included proteinuria, thrombocytopenia, neutropenia, anemia, leukopenia and diarrhea. There were two treatment-related fatalities (hepatic failure and pneumonitis). Analysis of bulk RNA sequencing data from the patients suggested that the triplet combination enhanced CD8+ T cell infiltration, resulting in a more immunologically active tumor microenvironment. Our study suggests that the combination of a PD-1 antibody, an HDACi, and a VEGF antibody could be a promising treatment regimen for patients with MSS/pMMR advanced colorectal cancer. ClinicalTrials.gov registration: NCT04724239 .

Diagnostic and Prognostic Ability of Contrast-Enhanced Unltrasound and Biomarkers in Hepatocellular Carcinoma Subtypes

OBJECTIVE

To investigate the diagnostic and prognostic value of contrast-enhanced ultrasound (CEUS) and clinical indicators of the vessels encapsulating tumor clusters (VETC) pattern and macrotrabecular-massive subtype in hepatocellular carcinoma (MTM-HCC).

METHODS

This retrospective study included patients who underwent preoperative CEUS and hepatectomy for HCC between August 2018 and August 2021. Multivariable logistic regression was performed to select independent correlated factors of VETC-HCC and MTM-HCC to develop nomogram models. The association between model outcomes and early postoperative HCC recurrence was assessed using Kaplan-Meier curve and Cox regression analysis.

RESULTS

The training cohort included 182 patients (54.3 ± 11.3 years, 168 males) and the validation cohort included 91 patients (54.8 ± 10.6 years, 81 males). Multivariate logistic regression analysis revealed that α-fetoprotein (AFP) levels (odds ratio [OR]: 2.26, 95% confidence interval [CI]: 1.49-3.42, p < 0.001), intratumoral nonenhancement (OR: 2.40, 95% CI: 1.02-5.64, p = 0.044), and the perfusion pattern in the CEUS arterial phase (OR: 2.27, 95% CI: 1.05-4.91, p = 0.038) were independent predictors of VETC-HCC. Besides, the former two were also independently associated with MTM-HCC (AFP level: OR: 2.36, 95% CI: 1.36-4.09, p = 0.002; intratumoral nonenhancement: OR: 3.72, 95% CI: 1.02-13.56, p = 0.046). Nomogram models were constructed based on the aforementioned indicators. Kaplan-Meier curve analysis indicated that predicted VETC-HCC or MTM-HCC exhibited higher rates of early recurrence (log-rank p < 0.001 and p = 0.002, respectively). Cox regression analysis showed that a high risk of VETC-HCC was independently correlated with early recurrence (p = 0.011).

CONCLUSION

CEUS combined with AFP levels can predict VETC-HCC/MTM-HCC and prognosis preoperatively.

Microbial metabolite enhances immunotherapy efficacy by modulating T cell stemness in pan-cancer

The immune checkpoint blockade (ICB) response in human cancers is closely linked to the gut microbiota. Here, we report that the abundance of commensal Lactobacillus johnsonii is positively correlated with the responsiveness of ICB. Supplementation with Lactobacillus johnsonii or tryptophan-derived metabolite indole-3-propionic acid (IPA) enhances the efficacy of CD8+ T cell-mediated αPD-1 immunotherapy. Mechanistically, Lactobacillus johnsonii collaborates with Clostridium sporogenes to produce IPA. IPA modulates the stemness program of CD8+ T cells and facilitates the generation of progenitor exhausted CD8+ T cells (Tpex) by increasing H3K27 acetylation at the super-enhancer region of Tcf7. IPA improves ICB responsiveness at the pan-cancer level, including melanoma, breast cancer, and colorectal cancer. Collectively, our findings identify a microbial metabolite-immune regulatory pathway and suggest a potential microbial-based adjuvant approach to improve the responsiveness of immunotherapy.

Camptothecin enhances the anti-tumor effect of low-dose apatinib combined with PD-1 inhibitor on hepatocellular carcinoma

Apatinib has been shown to apply to a variety of solid tumors, including advanced hepatocellular carcinoma. Preclinical and preliminary clinical results confirmed the synergistic antitumor effects of apatinib in combination with anti-programmed death-1 (PD-1) inhibitors. In this study, we investigated camptothecin (CPT) enhances the anti-tumor effect of low-dose apatinib combined with PD-1 inhibitor on hepatocellular carcinoma. CPT combined with a PD-1 inhibitor enhances the anti-tumor effects of low-dose apatinib in hepatocellular carcinoma which was evaluated in making use of the H22 mouse model (n = 32), which was divided into four groups. Immunohistochemical staining and western blotting were used to detect nuclear factor erythroid 2-related factor 2 (Nrf2) as well as sequestosome 1 (p62), vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2), PD-1, and programmed cell death ligand 1 (PD-L1). The results showed that the average size of the tumor of the combination group (Group D) was significantly less than that of the apatinib + PD-1 inhibitor group (Group C). The expression levels of Nrf2, p62, VEGFA, VEGFR2, PD-1, and PD-L1 in the apatinib + PD-1 inhibitor group(Group C) were lower than those in the control group (Group A) (P < 0.05). The expression levels of these genes in the apatinib + PD-1 inhibitor group (Group C) were significantly lower in the combination group (Group D) (P < 0.05). There was no obvious difference in body weight and liver and kidney functions between the four groups of mice. In conclusion, CPT improves the anti-tumor effect of low-dose apatinib combined with PD-1 inhibitor on hepatocellular carcinoma.

MicroRNA-126 selected with broad-spectrum analysis of microRNAs - a new predictive factor for the effectiveness of immunotherapy or chemoimmunotherapy in advanced NSCLC patients?

Introduction

Expression of PD-L1 on cancer cells is the only validated predictive factor for immunotherapy in NSCLC (Non-Small Cell Lung Cancer) patients. However, on this basis, it is difficult to predict the occurrence of resistance to immune checkpoint inhibitors (ICIs). MicroRNAs are widely studied as biomarkers of cancers. Our study was designed to determine whether microRNAs can be sensitive predictive factors in the qualification of NSCLC patients to first-line immunotherapy or chemoimmunotherapy.

Material and methods

The two-stage research on validation group (n=20) and study group (n=35) of patients with advanced NSCLC was conducted. Analysis of microRNAs expression by qPCR in plasma collected prior to the start of immunotherapy (pembrolizumab) or chemoimmunotherapy (combination of pembrolizumab with chemotherapy) was made. Broad-spectrum analysis of microRNAs expression was used in the studied group. Three microRNAs selected in that group as important for the effectiveness of ICIs were then examined in the validation group.

Results

In the studied group, significantly higher expression of miRNA-126-3p, miR-144-3p and miR-146-5p was observed in patients with long PFS compared to those with short PFS. In the validation group, low miRNA-126 expression indicated lower median progression-free survival and overall survival (2.3 vs. 5.0 months and 5.2 vs 11.2, respectively). These patients had a significantly higher risk of progression (HR= 2.92, 95% CI: 1.01 to 8.40, p=0.04) and death (HR=3.64, 95% CI: 1.22 to 10.84, p=0.02).

Conclusion

Our study showed that the expression of miR-126 in blood plasma may be a predictive factor for the effectiveness of first-line immunotherapy or chemoimmunotherapy in advanced NSCLC patients.

Blood Vessel-Targeted Therapy in Colorectal Cancer: Current Strategies and Future Perspectives

The vasculature is a key player and regulatory component in the multicellular microenvironment of solid tumors and, consequently, a therapeutic target. In colorectal carcinoma (CRC), antiangiogenic treatment was approved almost 20 years ago, but there are still no valid predictors of response. In addition, treatment resistance has become a problem. Vascular heterogeneity and plasticity due to species-, organ-, and milieu-dependent phenotypic and functional differences of blood vascular cells reduced the hope of being able to apply a standard approach of antiangiogenic therapy to all patients. In addition, the pathological vasculature in CRC is characterized by heterogeneous perfusion, impaired barrier function, immunosuppressive endothelial cell anergy, and metabolic competition-induced microenvironmental stress. Only recently, angiocrine proteins have been identified that are specifically released from vascular cells and can regulate tumor initiation and progression in an autocrine and paracrine manner. In this review, we summarize the history and current strategies for applying antiangiogenic treatment and discuss the associated challenges and opportunities, including normalizing the tumor vasculature, modulating milieu-dependent vascular heterogeneity, and targeting functions of angiocrine proteins. These new strategies could open perspectives for future vascular-targeted and patient-tailored therapy selection in CRC.

Endothelial cells in tumor microenvironment: insights and perspectives

The tumor microenvironment is a highly complex and dynamic mixture of cell types, including tumor, immune and endothelial cells (ECs), soluble factors (cytokines, chemokines, and growth factors), blood vessels and extracellular matrix. Within this complex network, ECs are not only relevant for controlling blood fluidity and permeability, and orchestrating tumor angiogenesis but also for regulating the antitumor immune response. Lining the luminal side of vessels, ECs check the passage of molecules into the tumor compartment, regulate cellular transmigration, and interact with both circulating pathogens and innate and adaptive immune cells. Thus, they represent a first-line defense system that participates in immune responses. Tumor-associated ECs are involved in T cell priming, activation, and proliferation by acting as semi-professional antigen presenting cells. Thus, targeting ECs may assist in improving antitumor immune cell functions. Moreover, tumor-associated ECs contribute to the development at the tumor site of tertiary lymphoid structures, which have recently been associated with enhanced response to immune checkpoint inhibitors (ICI). When compared to normal ECs, tumor-associated ECs are abnormal in terms of phenotype, genetic expression profile, and functions. They are characterized by high proliferative potential and the ability to activate immunosuppressive mechanisms that support tumor progression and metastatic dissemination. A complete phenotypic and functional characterization of tumor-associated ECs could be helpful to clarify their complex role within the tumor microenvironment and to identify EC specific drug targets to improve cancer therapy. The emerging therapeutic strategies based on the combination of anti-angiogenic treatments with immunotherapy strategies, including ICI, CAR T cells and bispecific antibodies aim to impact both ECs and immune cells to block angiogenesis and at the same time to increase recruitment and activation of effector cells within the tumor.

Spatiotemporal transformable nano-assembly for on-demand drug delivery to enhance anti-tumor immunotherapy

Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy, but fibrotic matrix severely blocks senescence inducers penetration and immune cells infiltration. Herein, we designed a cancer-associated fibroblasts (CAFs) triggered structure-transformable nano-assembly (HSD-P@V), which can directionally deliver valsartan (Val, CAFs regulator) and doxorubicin (DOX, senescence inducer) to the specific targets. In detail, DOX is conjugated with hyaluronic acid (HA) via diselenide bonds (Se-Se) to form HSD micelles, while CAFs-sensitive peptide is grafted onto the HSD to form a hydrophilic polymer, which is coated on Val nanocrystals (VNs) surface for improving the stability and achieving responsive release. Once arriving at tumor microenvironment and touching CAFs, HSD-P@V disintegrates into VNs and HSD micelles due to sensitive peptide detachment. VNs can degrade the extracellular matrix, leading to the enhanced penetration of HSD. HSD targets tumor cells, releases DOX to induce senescence, and recruits effector immune cells. Furthermore, senescent cells are cleared by the recruited immune cells to finish the integrated anti-tumor therapy. In vitro and in vivo results show that the nano-assembly remarkably inhibits tumor growth as well as lung metastasis, and extends tumor-bearing mice survival. This work provides a promising paradigm of programmed delivering multi-site nanomedicine for cancer immunotherapy.

Quantitative multiplex immunohistochemistry reveals inter-patient lymphovascular and immune heterogeneity in primary cutaneous melanoma

Introduction

Quantitative, multiplexed imaging is revealing complex spatial relationships between phenotypically diverse tumor infiltrating leukocyte populations and their prognostic implications. The underlying mechanisms and tissue structures that determine leukocyte distribution within and around tumor nests, however, remain poorly understood. While presumed players in metastatic dissemination, new preclinical data demonstrates that blood and lymphatic vessels (lymphovasculature) also dictate leukocyte trafficking within tumor microenvironments and thereby impact anti-tumor immunity. Here we interrogate these relationships in primary human cutaneous melanoma.

Methods

We established a quantitative, multiplexed imaging platform to simultaneously detect immune infiltrates and tumor-associated vessels in formalin-fixed paraffin embedded patient samples. We performed a discovery, retrospective analysis of 28 treatment-naïve, primary cutaneous melanomas.

Results

Here we find that the lymphvasculature and immune infiltrate is heterogenous across patients in treatment naïve, primary melanoma. We categorized five lymphovascular subtypes that differ by functionality and morphology and mapped their localization in and around primary tumors. Interestingly, the localization of specific vessel subtypes, but not overall vessel density, significantly associated with the presence of lymphoid aggregates, regional progression, and intratumoral T cell infiltrates.

Discussion

We describe a quantitative platform to enable simultaneous lymphovascular and immune infiltrate analysis and map their spatial relationships in primary melanoma. Our data indicate that tumor-associated vessels exist in different states and that their localization may determine potential for metastasis or immune infiltration. This platform will support future efforts to map tumor-associated lymphovascular evolution across stage, assess its prognostic value, and stratify patients for adjuvant therapy.

Extra villous trophoblast-derived PDL1 can ameliorate macrophage inflammation and promote immune adaptation associated with preeclampsia

INTRODUCTION

Severe preeclampsia (sPE) is a systemic syndrome that may originate from chronic inflammation. Maintaining maternal-fetal hemostasis by the co-inhibitory molecule programmed death ligand 1 (PDL1) can be favorable for ameliorating inflammation from immune cells. Apart from programmed death 1 (PD1) expression, decidual macrophages (dMs) produce inflammatory cytokines, in response to cells which express PDL1. However, strong evidence is lacking regarding whether the PDL1/PD1 interaction between trophoblasts and decidual macrophages affects inflammation during sPE development.

METHODS

To determine whether the trophoblast-macrophage crosstalk via the PDL1/PD1 axis modulates the inflammatory response in sPE-like conditions, at first, maternal-fetal tissues from sPE and normal patients were collected, and the PDL1/PD1 distribution was analyzed by Western blot, immunohistochemistry/ immunofluorescence and flow cytometry. Next, a coculture system was established and flow cytometry was used to identify how PDL1 was involved in macrophage-related inflammation under hypoxic stress. Transcriptional analysis was performed to clarify the inflammation-associated pathway induced by the PDL1/PD1 interaction. Finally, the Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) mouse model was used to examine the effect of PDL1 on macrophage-related inflammation by measuring PE-like symptoms.

RESULTS

In maternal-fetal tissue from sPE patients, placental extravillous trophoblasts (EVTs) and dMs had a surprisingly increase of PDL1 and PD1 expression, respectively, accompanied by a higher percentage of CD68 +CD86 + dMs. In vitro experiments showed that trophoblast-derived PDL1 under hypoxia interacted with PD1 on CD14 +CD80 +macrophages, leading to suppression of inflammation through the TNFα-p38/NFκB pathway. Accordingly, the PE-like mouse model showed a reversal of PE-like symptoms and a reduced F4/80 + CD86 + macrophage percentage in the uterus in response to recombinant PDL1 protein administration, indicating the protective effect of PDL1.

DISCUSSION

Our results initially explained an immunological adaptation of trophoblasts under placental hypoxia, although this protection was insufficient. Our findings suggest the possible capacity of modulating PDL1 expression as a potential therapeutic strategy to target the inflammatory response in sPE.

Clinical Potential of YY1-Hypoxia Axis for Vascular Normalization and to Improve Immunotherapy

Abnormal vasculature in solid tumors causes poor blood perfusion, hypoxia, low pH, and immune evasion. It also shapes the tumor microenvironment and affects response to immunotherapy. The combination of antiangiogenic therapy and immunotherapy has emerged as a promising approach to normalize vasculature and unlock the full potential of immunotherapy. However, the unpredictable and redundant mechanisms of vascularization and immune suppression triggered by tumor-specific hypoxic microenvironments indicate that such combination therapies need to be further evaluated to improve patient outcomes. Here, we provide an overview of the interplay between tumor angiogenesis and immune modulation and review the function and mechanism of the YY1-HIF axis that regulates the vascular and immune tumor microenvironment. Furthermore, we discuss the potential of targeting YY1 and other strategies, such as nanocarrier delivery systems and engineered immune cells (CAR-T), to normalize tumor vascularization and re-establish an immune-permissive microenvironment to enhance the efficacy of cancer therapy.

Hypoxia-activated prodrug and antiangiogenic therapies cooperatively treat pancreatic cancer but elicit immunosuppressive G-MDSC infiltration

We previously showed that ablation of tumor hypoxia can sensitize tumors to immune checkpoint blockade (ICB). Here, we used a Kras+/G12D TP53+/R172H Pdx1-Cre-derived (KPC-derived) model of pancreatic adenocarcinoma to examine the tumor response and adaptive resistance mechanisms involved in response to 2 established methods of hypoxia-reducing therapy: the hypoxia-activated prodrug TH-302 and vascular endothelial growth factor receptor 2 (VEGFR-2) blockade. The combination of both modalities normalized tumor vasculature, increased DNA damage and cell death, and delayed tumor growth. In contrast with prior cancer models, the combination did not alleviate overall tissue hypoxia or sensitize these KPC tumors to ICB therapy despite qualitative improvements to the CD8+ T cell response. Bulk tumor RNA sequencing, flow cytometry, and adoptive myeloid cell transfer suggested that treated tumor cells increased their capacity to recruit granulocytic myeloid-derived suppressor cells (G-MDSCs) through CCL9 secretion. Blockade of the CCL9/CCR1 axis could limit G-MDSC migration, and depletion of Ly6G-positive cells could sensitize tumors to the combination of TH-302, anti-VEGFR-2, and ICB. Together, these data suggest that pancreatic tumors modulate G-MDSC migration as an adaptive response to vascular normalization and that these immunosuppressive myeloid cells act in a setting of persistent hypoxia to maintain adaptive immune resistance.

Apatinib combined with camrelizumab in the treatment of recurrent/metastatic nasopharyngeal carcinoma: a prospective multicenter phase II study

Background

Preclinical studies demonstrated that immune checkpoint inhibitors combined with antiangiogenic drugs have a synergistic anti-tumor effect. This present phase II trial aimed to evaluate the efficacy and safety of apatinib combined with camrelizumab in patients with recurrent/metastatic nasopharyngeal carcinoma (RM-NPC).

Methods

Patients with RM-NPC were administered with apatinib at 250 mg orally once every day and with camrelizumab at 200 mg via intravenous infusion every 2 weeks until the disease progressed or toxicity became unacceptable. The objective response rate (ORR) was the primary endpoint, assessed using RECIST version 1.1. Progression-free survival (PFS), overall survival (OS), disease control rate (DCR) and safety were the key secondary endpoints. This study was registered with ClinicalTrials.gov, NCT04350190.

Results

This study enrolled 26 patients with RM-NPC between January 14, 2021 and September 15, 2021. At data cutoff (March 31, 2023), the median duration of follow-up was 16 months (ranging from 1 to 26 months). The ORR was 38.5% (10/26), the disease control rate (DCR) was 61.5% (16/26), and the median PFS was 6 months (IQR 3.0-20.0). The median OS was 14 months (IQR 6.0-21.25). Treatment-related grade 3 or 4 adverse events occurred in seven (26.9%) patients, and comprised anemia (7.7%), stomatitis (3.8%), headache (3.8%), pneumonia (7.7%), and myocarditis (3.8%). There were no serious treatment-related adverse events or treatment-related deaths.

Conclusion

In patients with RM-NPC, apatinib plus camrelizumab showed promising antitumor activity and manageable toxicities.

Targeting vascular normalization: a promising strategy to improve immune-vascular crosstalk in cancer immunotherapy

Blood vessels are a key target for cancer therapy. Compared with the healthy vasculature, tumor blood vessels are extremely immature, highly permeable, and deficient in pericytes. The aberrantly vascularized tumor microenvironment is characterized by hypoxia, low pH, high interstitial pressure, and immunosuppression. The efficacy of chemotherapy, radiotherapy, and immunotherapy is affected by abnormal blood vessels. Some anti-angiogenic drugs show vascular normalization effects in addition to targeting angiogenesis. Reversing the abnormal state of blood vessels creates a normal microenvironment, essential for various cancer treatments, specifically immunotherapy. In addition, immune cells and molecules are involved in the regulation of angiogenesis. Therefore, combining vascular normalization with immunotherapy may increase the efficacy of immunotherapy and reduce the risk of adverse reactions. In this review, we discussed the structure, function, and formation of abnormal vessels. In addition, we elaborated on the role of the immunosuppressive microenvironment in the formation of abnormal vessels. Finally, we described the clinical challenges associated with the combination of immunotherapy with vascular normalization, and highlighted future research directions in this therapeutic area.

Saikosaponin-d regulates angiogenesis in idiopathic pulmonary fibrosis through angiopoietin/Tie-2 pathway

OBJECTIVE

Idiopathic pulmonary fibrosis (IPF) is considered as a chronic interstitial lung disease with underlying mechanism of IPF remaining unclear, while there are no definitive treatment options. In recent years, scientists have gradually paid attention to the influence of angiogenesis on IPF. Because IPF is a progressive with microvascular remodeling disorder, scientists have postulated that angiogenesis may also be one of the initiating and contributing factors of the disease. Bupleurum is a common natural Chinese herbal medicine with antibacterial, anti-inflammatory, anti-tumor and other pharmacological effects. As the most important active monomer of Bupleurum, Saikosaponin-d (SSd) is a new discovery with anti-pulmonary fibrosis (PF) activity. This study attempts to investigate the role of SSd in the interference of PF through regulation of angiogenesis in IPF through Angiopoietin (Angpt) /Tie receptor 2 (Tie2) pathway.

METHODS

Randomly, we allocated C57BL/6 mice into four groups (n = 20 in each group). Afterwards, establishment of IPF model was accomplished via intratracheal administration of bleomycin (BLM, 5 mg/kg), while corresponding drug intervention was given accordingly. On 3rd, 7th, 14th and 28th days after modeling, we performed histopathological examination through staining. Meanwhile, immunohistochemistry (IHC) of PF and the expression of related factors were observed, while Ang/Tie2 pathway was assessed by ELISA with the effect of SSd on angiogenesis related proteins in IPF being explored with IHC and Western Blot technique.

RESULTS

Our results showed that SSd could reduce inflammation and PF levels in lung tissue of experimental mice, while levels of angiogenesis-related factors, namely Tie-2, Ang-1 and ANGPT2 (Ang-2), fibrosis- associated factors like Alpha-smooth muscle actin (α-SMA), collagen-I and hydroxyproline in SSd and dexamethasone (DXM) mice were significantly reduced at each time point compared to BLM (p < 0.01). Additionally, we discovered substantial decreased expressions of Ang-1, Ang-2, Tie-2, α-SMA and collagen-I at protein level in SSd and DXM mice at each time point compared to BLM (p < 0.05). Besides, insignificant differences were observed between SSd and DXM groups (p > 0.05).

CONCLUSION

This study has demonstrated that SSd could down-regulate the expression of ANG-1, Ang-2 and Tie2 in the Ang/Tie2 pathway, and may reduce lung inflammation and PF in BLM-induced mice via inhibition of angiogenesis.

Alleviating hypoxia to improve cancer immunotherapy

Tumor hypoxia resulting from abnormal and dysfunctional tumor vascular network poses a substantial obstacle to immunotherapy. In fact, hypoxia creates an immunosuppressive tumor microenvironment (TME) through promoting angiogenesis, metabolic reprogramming, extracellular matrix remodeling, epithelial-mesenchymal transition (EMT), p53 inactivation, and immune evasion. Vascular normalization, a strategy aimed at restoring the structure and function of tumor blood vessels, has been shown to improve oxygen delivery and reverse hypoxia-induced signaling pathways, thus alleviates hypoxia and potentiates cancer immunotherapy. In this review, we discuss the mechanisms of tumor tissue hypoxia and its impacts on immune cells and cancer immunotherapy, as well as the approaches to induce tumor vascular normalization. We also summarize the evidence supporting the use of vascular normalization in combination with cancer immunotherapy, and highlight the challenges and future directions of this overlooked important field. By targeting the fundamental problem of tumor hypoxia, vascular normalization proposes a promising strategy to enhance the efficacy of cancer immunotherapy and improve clinical outcomes for cancer patients.

5α-Hydroxycostic acid inhibits choroidal neovascularization in rats through a dual signalling pathway mediated by VEGF and angiopoietin 2

BACKGROUND

5α-Hydroxycostic acid is a eudemane sesquiterpene that is isolated from the natural plant, Laggera alata. It exerts anti-inflammatory and anti-angiogenic effects on human breast cancer cells, but its role and underlying mechanism in choroidal neovascularization (CNV) are still unclear. We conducted a study to verify that 5α-Hydroxycostic acid can inhibit the formation and leakage of CNV, and describe the possible dual pathway by which it exerts its inhibitory effects in this process.

METHODS

An in vitro model of choroidal neovascularization was established using VEGF164, while a rat model of choroidal neovascularization was established using a 532 nm laser. In both models, the effects of 5α-Hydroxycostic acid in vivo and in vitro were evaluated to determine its inhibitory effect on abnormal cell proliferation, migration and tubule formation, as well as its effect on pathological changes in choroidal tissues and the area of neovascularization leakage in rats. The levels of components in the VEGF/VEGFR and Ang2/Tie2 signaling pathways were measured in tissues and cells.

RESULTS

In vitro experiments have shown that 5α-Hydroxycostic acid can inhibit abnormal cell proliferation, migration and angiogenesis. Additionally, 5α-Hydroxycostic acid enhances cell adhesion by inhibiting the phosphorylation pathways of VEGFR2 and Tie2. In vivo experiments demonstrated that 5α-Hydroxycostic acid has a positive therapeutic effect on choroidal neovascularization in rats. It can effectively reduce vascular leakage, consistent with the results of the cell experiments.

CONCLUSION

5α-Hydroxycostic acid can inhibit choroidal neovascularization by interfering with the VEGF- and Ang2/Tie2-related pathways, and it may be a good candidate drug for treating CNV.

Depletion of slow-cycling PDGFRα+ADAM12+ mesenchymal cells promotes antitumor immunity by restricting macrophage efferocytosis

The capacity to survive and thrive in conditions of limited resources and high inflammation is a major driver of tumor malignancy. Here we identified slow-cycling ADAM12+PDGFRα+ mesenchymal stromal cells (MSCs) induced at the tumor margins in mouse models of melanoma, pancreatic cancer and prostate cancer. Using inducible lineage tracing and transcriptomics, we demonstrated that metabolically altered ADAM12+ MSCs induced pathological angiogenesis and immunosuppression by promoting macrophage efferocytosis and polarization through overexpression of genes such as Gas6, Lgals3 and Csf1. Genetic depletion of ADAM12+ cells restored a functional tumor vasculature, reduced hypoxia and acidosis and normalized CAFs, inducing infiltration of effector T cells and growth inhibition of melanomas and pancreatic neuroendocrine cancer, in a process dependent on TGF-β. In human cancer, ADAM12 stratifies patients with high levels of hypoxia and innate resistance mechanisms, as well as factors associated with a poor prognosis and drug resistance such as AXL. Altogether, our data show that depletion of tumor-induced slow-cycling PDGFRα+ MSCs through ADAM12 restores antitumor immunity.

The possible dual role of Ang-2 in the prognosis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) features a dense desmoplastic stroma, which raises the intratumoral interstitial pressure leading to vascular collapse and hypoxia, inducing angiogenesis. Vascular growth factors, such as vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2), increase in PDAC. A high VEGF and a high circulating Ang-2 associate with shorter survival in PDAC. In addition to the circulatory Ang-2, PDAC endothelial and epithelial cells express Ang-2. No correlation between tumor epithelial nor endothelial cell Ang-2 expression and survival has been published. We aimed to examine Ang-2 expression and survival. This study comprised PDAC surgical patients at Helsinki University Hospital in 2000-2013. Ang-2 immunohistochemistry staining was completed on 168 PDAC patient samples. Circulating Ang-2 levels were measured using ELISA in the sera of 196 patients. Ang-2 levels were assessed against clinical data and patient outcomes. A low tumor epithelial Ang-2 expression predicted shorter disease-specific survival (DSS) compared with a high expression (p = 0.003). A high serum Ang-2 associated with shorter DSS compared with a low circulating Ang-2 (p = 0.016). Ang-2 seemingly plays a dual role in PDAC survival. Further studies are needed to determine the mechanisms causing tumor cell Ang-2 expression and its positive association with survival.

Research advances in mechanism of antiangiogenic therapy combined with immune checkpoint inhibitors for treatment of non-small cell lung cancer

Immunotherapy has changed the treatment strategy of non-small cell lung cancer (NSCLC) in recent years, among which anti-PD-1/PD-L1 antibodies are the most used. However, the majority of patients with NSCLC do not derive benefit from immune checkpoint inhibitors (ICIs). Vascular abnormalities are a hallmark of most solid tumors and facilitate immune evasion. Thus, combining antiangiogenic therapies might increase the effectiveness of anti-PD-1/PD-L1 antibodies. In this paper, the mechanisms of anti-angiogenic agents combined with anti-PD-1/PD-L1 antibodies are illustrated, moreover, relevant clinical studies and predictive immunotherapeutic biomarkers are summarized and analyzed, in order to provide more treatment options for NSCLC patients.

Angiopoietin-2 blockade suppresses growth of liver metastases from pancreatic neuroendocrine tumors by promoting T cell recruitment

Improving the management of metastasis in pancreatic neuroendocrine tumors (PanNETs) is critical, as nearly half of patients with PanNETs present with liver metastases, and this accounts for the majority of patient mortality. We identified angiopoietin-2 (ANGPT2) as one of the most upregulated angiogenic factors in RNA-Seq data from human PanNET liver metastases and found that higher ANGPT2 expression correlated with poor survival rates. Immunohistochemical staining revealed that ANGPT2 was localized to the endothelial cells of blood vessels in PanNET liver metastases. We observed an association between the upregulation of endothelial ANGPT2 and liver metastatic progression in both patients and transgenic mouse models of PanNETs. In human and mouse PanNET liver metastases, ANGPT2 upregulation coincided with poor T cell infiltration, indicative of an immunosuppressive tumor microenvironment. Notably, both pharmacologic inhibition and genetic deletion of ANGPT2 in PanNET mouse models slowed the growth of PanNET liver metastases. Furthermore, pharmacologic inhibition of ANGPT2 promoted T cell infiltration and activation in liver metastases, improving the survival of mice with metastatic PanNETs. These changes were accompanied by reduced plasma leakage and improved vascular integrity in metastases. Together, these findings suggest that ANGPT2 blockade may be an effective strategy for promoting T cell infiltration and immunostimulatory reprogramming to reduce the growth of liver metastases in PanNETs.

CACNA1C mutation as a prognosis predictor of immune checkpoint inhibitor in skin cutaneous melanoma

Aims: There is an urgent need for appropriate biomarkers that can precisely and reliably predict immunotherapy efficacy, as immunotherapy responses can differ in skin cutaneous melanoma (SKCM) patients. Methods: In this study, univariate regression models and survival analysis were used to examine the link between calcium voltage-gated channel subunit alpha 1C (CACNA1C) mutation status and immunotherapy outcome in SKCM patients receiving immunotherapy. Mutational landscape, immunogenicity, tumor microenvironment and pathway-enrichment analyses were also performed. Results: The CACNA1C mutation group had a better prognosis, higher immunogenicity, lower endothelial cell infiltration, significant enrichment of antitumor immune response pathways and significant downregulation of protumor pathways. Conclusion: CACNA1C mutation status is anticipated to be a biomarker for predicting melanoma immunotherapy effectiveness.

PB101, a VEGF- and PlGF-targeting decoy protein, enhances antitumor immunity and suppresses tumor progression and metastasis

Antiangiogenic therapy is a recognized method for countering the immunosuppressive tumor microenvironment (TME) and improving anti-tumor immunity. PB101 is a glycosylated decoy receptor that binds to VEGF-A and PlGF with high affinity, based on the VEGFR1 backbone. Here, we elucidated PB101-induced remodeling of tumor angiogenesis and immunity, which enhances anti-PD-L1 immune checkpoint blockade. PB101 inhibited tumor growth by suppressing angiogenesis and enhancing CD8+ T cell infiltration into the tumors. PB101 induced robust reprogramming of antitumor immunity and activates intratumoral CD8+ T cells. Anti-tumor efficacy of PB101 is mostly dependent on CD8+ T cells and IFN-γ. PB101 reprograms tumor immunity in a manner distinct from that of the conventional VEGF decoy receptor, VEGF-trap. With its potent immune-modulating capability, PB101 synergizes with an anti-PD-L1, triggering strengthened antitumor immunity. Combining PB101 and anti-PD-L1 could establish durable protective immunity against tumor recurrence and metastasis. The findings of this study offer scientific rationales for further clinical development of PB101, particularly when used in combination with immune checkpoint inhibitors, as a potential treatment for advanced cancers.

Exploring the crosstalk between endothelial cells, immune cells, and immune checkpoints in the tumor microenvironment: new insights and therapeutic implications

The tumor microenvironment (TME) is a highly intricate milieu, comprising a multitude of components, including immune cells and stromal cells, that exert a profound influence on tumor initiation and progression. Within the TME, angiogenesis is predominantly orchestrated by endothelial cells (ECs), which foster the proliferation and metastasis of malignant cells. The interplay between tumor and immune cells with ECs is complex and can either bolster or hinder the immune system. Thus, a comprehensive understanding of the intricate crosstalk between ECs and immune cells is essential to advance the development of immunotherapeutic interventions. Despite recent progress, the underlying molecular mechanisms that govern the interplay between ECs and immune cells remain elusive. Nevertheless, the immunomodulatory function of ECs has emerged as a pivotal determinant of the immune response. In light of this, the study of the relationship between ECs and immune checkpoints has garnered considerable attention in the field of immunotherapy. By targeting specific molecular pathways and signaling molecules associated with ECs in the TME, novel immunotherapeutic strategies may be devised to enhance the efficacy of current treatments. In this vein, we sought to elucidate the relationship between ECs, immune cells, and immune checkpoints in the TME, with the ultimate goal of identifying novel therapeutic targets and charting new avenues for immunotherapy.

Immunotherapies targeting tumor vasculature: challenges and opportunities

Angiogenesis is a hallmark of cancer biology, and neoadjuvant therapies targeting either tumor vasculature or VEGF signaling have been developed to treat solid malignant tumors. However, these therapies induce complete vascular depletion leading to hypoxic niche, drug resistance, and tumor recurrence rate or leading to impaired delivery of chemo drugs and immune cell infiltration at the tumor site. Achieving a balance between oxygenation and tumor growth inhibition requires determining vascular normalization after treatment with a low dose of antiangiogenic agents. However, monotherapy within the approved antiangiogenic agents' benefits only some tumors and their efficacy improvement could be achieved using immunotherapy and emerging nanocarriers as a clinical tool to optimize subsequent therapeutic regimens and reduce the need for a high dosage of chemo agents. More importantly, combined immunotherapies and nano-based delivery systems can prolong the normalization window while providing the advantages to address the current treatment challenges within antiangiogenic agents. This review summarizes the approved therapies targeting tumor angiogenesis, highlights the challenges and limitations of current therapies, and discusses how vascular normalization, immunotherapies, and nanomedicine could introduce the theranostic potentials to improve tumor management in future clinical settings.

Therapeutic advances targeting tumor angiogenesis in pancreatic cancer: Current dilemmas and future directions

Pancreatic cancer (PC) is one of the most lethal malignancies, which is generally resistant to various treatments. Tumor angiogenesis is deemed to be a pivotal rate-determining step for tumor growth and metastasis. Therefore, anti-angiogenetic therapy is a rational strategy to treat various cancers. However, numerous clinical trials on anti-angiogenetic therapies for PC are overwhelmingly disappointing. The unique characteristics of tumor blood vessels in PC, which are desperately lacking and highly compressed by the dense desmoplastic stroma, are reconsidered to explore some optimized strategies. In this review, we mainly focus on its specific characteristics of tumor blood vessels, discuss the current dilemmas of anti-angiogenic therapy in PC and their underlying mechanisms. Furthermore, we point out the future directions, including remodeling the abnormal vasculature or even reshaping the whole tumor microenvironment in which they are embedded to improve tumor microcirculation, and then create therapeutic vulnerabilities to the current available therapeutic strategies.

Advances in targeted therapy and immunotherapy for melanoma (Review)

Melanoma is the most aggressive and deadly type of skin cancer and is known for its poor prognosis as soon as metastasis occurs. Since 2011, new and effective therapies for metastatic melanoma have emerged, with US Food and Drug Administration approval of multiple targeted agents, such as V-Raf murine sarcoma viral oncogene homolog B1/mitogen-activated protein kinase kinase inhibitors and multiple immunotherapy agents, such as cytotoxic T lymphocyte-associated protein 4 and anti-programmed cell death protein 1/ligand 1 blockade. Based on insight into the respective advantages of the above two strategies, the present article provided a review of clinical trials of the application of targeted therapy and immunotherapy, as well as novel approaches of their combinations for the treatment of metastatic melanoma in recent years, with a focus on upcoming initiatives to improve the efficacy of these treatment approaches for metastatic melanoma.