High Endothelial Venules: A Vascular Perspective on Tertiary Lymphoid Structures in Cancer

Tertiary lymphoid structures achieve 'cold' to 'hot' transition by remodeling the cold tumor microenvironment

Immune checkpoint blockade (ICB) therapies have demonstrated significant clinical efficacy in immune-infiltrated tumors such as melanoma and non-small cell lung cancer. However, "cold tumors"-including ovarian cancer, pancreatic cancer, and gliomas-exhibit insufficient immune infiltration, leading to poor therapeutic responses to ICBs and limited improvement in patient prognosis. Recent studies have shown that tumor-associated tertiary lymphoid structures (TLSs) can induce strong local immune responses within the tumor microenvironment (TME), serving as important biological markers for predicting ICB therapy efficacy. Notably, preclinical and clinical studies on cold tumors have confirmed that TLSs can potently enhance ICB efficacy through TME remodeling-a breakthrough that has attracted considerable attention. Here, we systematically examine the immunological profile of cold tumors and decipher the mechanistic basis for their impaired immune cell infiltration. We further delineate the distinctive features of tumor-associated TLSs in generating antitumor immunity and establish criteria for their identification. Significantly, we emphasize the unique capability of TLSs to reprogram the immunosuppressive tumor microenvironment characteristic of cold tumors. Based on these insights, we evaluate clinical evidence supporting TLS-mediated enhancement of ICB efficacy and discuss emerging strategies for exogenous TLSs induction.

The impact of metabolic reprogramming on tertiary lymphoid structure formation: enhancing cancer immunotherapy

BACKGROUND

Cancer immunotherapy has achieved unprecedented success in the field of cancer therapy. However, its potential is constrained by a low therapeutic response rate.

MAIN BODY

Tertiary lymphoid structure (TLS) plays a crucial role in antitumor immunity and is associated with a good prognosis. Metabolic reprogramming, as a hallmark of the tumor microenvironment, can influence tumor immunity and promote the formation of follicular helper T cells and germinal centers. However, many current studies focus on the correlation between metabolism and TLS formation factors, and there is insufficient direct evidence to suggest that metabolism drives TLS formation. This review provided a comprehensive summary of the relationship between metabolism and TLS formation, highlighting glucose metabolism, lipid metabolism, amino acid metabolism, and vitamin metabolism.

CONCLUSIONS

In the future, an in-depth exploration of how metabolism affects cell interactions and the role of microorganisms in TLS will significantly advance our understanding of metabolism-enhanced antitumor immunity.

Infiltrating B-cell subtypes and associated hub genes in nasopharyngeal carcinoma identified from integrated single-cell, bulk RNA-sequencing, and immunohistochemical data

BACKGROUND

Nasopharyngeal carcinoma (NPC) is associated with lymphocyte infiltration; however, the majority of research on NPC has focused on the role of T cells, with relatively little known about the roles of B cells and their subtypes. Therefore, we evaluated the prognostic value of CD20 + B cell density and B-cell subtypes along with their functional enrichment and hub genes in NPC.

METHODS

The prognostic value of CD20 + B-cell density for distant metastasis-free survival (DMFS), overall survival (OS), and progression-free survival (PFS) was explored by immunohistochemistry using multivariate analysis. Transcriptomic expression data from Gene Expression Omnibus (GEO) datasets were analyzed to identify B-cell subtypes and their functional enrichment in NPC tissues. Pseudotime trajectory analysis was performed to evaluate the B-cell differentiation trajectory and hub genes were identified using Cytoscape software.

RESULTS

Patients with NPC exhibiting a high infiltrating density of CD20+ B cells showed significantly better 5-year DMFS, OS, and PFS compared to those of patients with a low infiltrating density. Naïve B cells, switched memory B cells, exhausted B cells, and plasma cells were identified as key B-cell subtypes infiltrating NPC tumors, with naïve B cells showing the highest infiltration levels associated with a better prognosis. Naïve B cells were closely associated with immune pathways and the hub genes were typical markers for T and B cells.

CONCLUSION

A high infiltrating density of B cells showed strong prognostic value in patients with NPC. Naïve B cells may play an important role in tumor immunity for NPC.

Pipelines for lymphocyte homeostasis maintenance during cancer immunotherapy

In general, increasing lymphocyte entry into tumor microenvironment (TME) and limiting their efflux will have a positive effect on the efficacy of immunotherapy. Current studies suggest maintenance lymphocyte homeostasis during cancer immunotherapy through the two pipelines tumor-associated high endothelial venules and lymphatic vessels. Tumor-associated high endothelial venules (TA-HEVs) play a key role in cancer immunotherapy through facilitating lymphocyte trafficking to the tumor. While tumor-associated lymphatic vessels, in contrast, may promote the egress of lymphocytes and restrict their function. Therefore, the two traffic control points might be potential to maintain lymphocyte homeostasis in cancer during immunotherapy. Herein, we highlight the unexpected roles of lymphocyte circulation regulated by the two gateways for through reviewing the biological characters and functions of TA-HEVs and tumor-associated lymphatic vessels in the entry, positioning and exit of lymphocyte cells in TME during anti-tumor immunity.

Lymphoid Aggregates in Canine Cutaneous and Subcutaneous Sarcomas: Immunohistochemical and Gene Expression Evidence for Tertiary Lymphoid Structures

Canine cutaneous/subcutaneous soft-tissue sarcomas (STS) are diversely derived mesenchymal neoplasms with a risk of recurrence and/or metastasis depending on the extent of surgical excision and histologic grade. Lymphoid aggregates (LAs) are often described in these tumours but not characterised. In humans, LA characterised as tertiary lymphoid structures (TLSs) improve the prognosis of many tumours, including sarcomas. We sought to determine if LA meeting a size criterion (> 700 cells) in canine sarcomas met the criteria of TLS and the overall prevalence of LA of any size. RNA expression in large LAs versus aggregate-adjacent sarcoma tissue (AAS) was measured in laser capture microdissected tissue and compared to curl-derived RNA from aggregate-free sarcomas and lymph nodes. CD3, CD20, MUM-1 and PNAd expressions were measured using immunohistochemistry. CD20 and CD3 mRNA were more highly expressed in LA versus AAS (13.8 fold, p = 0.0003 and 2.3 fold, p = 0.043). This was supported by the IHC findings. The large LAs were also enriched in chemokine RNA expression characteristic of TLS (CXCR5 5.8 fold, p < 00001, CCL19 3.68 fold, p = 0.0209, CCL21 6.87 fold, p = 0.0209 and CXCL13 2.68 fold, p = 0.0924). Plasma cells and high endothelial venules were identified in LA containing tumours but not in control tissue. Large LAs were present in 12% of tumours, and LA of any size in 30%. We conclude that large LAs in canine STS are consistent with TLS.

Tertiary lymphoid structure formation induced by LIGHT-engineered and photosensitive nanoparticles-decorated bacteria enhances immune response against colorectal cancer

Tertiary lymphoid structures (TLSs) are known to enhance the prognosis of patients with colorectal cancer (CRC) by fostering an immunologically active tumor microenvironment (TME). Inducing TLS formation therapeutically holds promise for treating immunologically cold CRC, though it poses technical challenges. Here, we design and fabricate a photosensitive bacterial system named E@L-P/ICG. This system is engineered bacteria internally loaded with the cytokine LIGHT and surface-modified with PLGA/ICG nanoparticles (P/ICG NPs). Once accumulated in orthotopic colonic tumors in mice, E@L-P/ICG generates a mild photothermal effect under laser irradiation due to the photosensitive P/ICG NPs. This photothermal effect triggers the self-rupture of E@L-P/ICG and the death of surrounding tumor cells to release adjuvants and antigens, respectively, which in turn synergistically activate the adaptive immune responses. Furthermore, the cytokine LIGHT released from ruptured E@L-P/ICG stimulates the generation of high endothelial vessels (HEVs), promoting lymphocyte recruitment within the TME. These mechanisms lead to the TLS formation in CRC, which further boosts adaptive immune responses through effective infiltration of T cells and B cells, resulting in effectively inhibited tumor growth and extended survival of mice. Our study shows the potential of the E@L-P/ICG system in photosensitively inducing the TLS formation to treat CRC in clinic.

Distinct maturity and spatial distribution of tertiary lymphoid structures in head and neck squamous cell carcinoma: implications for tumor immunity and clinical outcomes

The influence of tertiary lymphoid structures (TLSs) on disease progression and the response to immunotherapy in head and neck squamous cell carcinoma (HNSCC) is well established, yet the heterogeneity among these structures remains largely unexplored. We utilized digital spatial profiling technology to perform in situ transcriptomic sequencing of TLSs across varying levels of maturation and distinct tumor regions within HNSCC. We assessed the prognostic significance of TLS maturation and spatial distribution in 260 patients with HNSCC through hematoxylin and eosin staining and multiplex immunohistochemistry. Furthermore, we established a TLS scoring system to predict survival in patients with HNSCC. Our study revealed that mature TLSs in the intratumor region (Intra-TLSs) of HNSCC, enriched with memory B cells, plasma cells, and CD4+ T cells, presented increased B-cell activity gene expression. Conversely, early TLSs (E-TLSs), abundant in endothelial cells, fibroblasts, and regulatory T cells, express epithelial‒mesenchymal transition (EMT)-related genes, potentially fostering tumor growth. Compared with mature TLSs within the peritumoral region (Peri-TLSs), mature Intra-TLSs have greater memory B-cell and macrophage densities and upregulate genes involved in B-cell receptor signaling and immune effector processes. Mature Peri-TLSs, characterized by endothelial cell enrichment and EMT receptor interaction genes, may contribute to tumor progression and immune evasion. Patients with mature Intra-TLSs or invasive margin TLSs (Invas-TLSs) have improved 5-year survival, whereas those with mature Peri-TLSs have poorer prognoses. By integrating TLS maturity and distribution in HNSCC, we developed a TLS scoring system to guide personalized treatments, which is crucial for predicting outcomes.

Comparative Automated Quantification of Tertiary Lymphoid Structures in Two Distinct Mouse Models of Inflammation

Tertiary lymphoid structures (TLS) have been reported to form within nonlymphoid tissues upon various inflammatory conditions, such as tumors or bacterial infections. In particular, the lungs of patients with NSCLC or bacterial infections (such as tuberculosis or aspergillosis) are the sites of TLS neogenesis. An increasing number of preclinical models have been used over the years to recapitulate as accurately as possible the mechanisms and kinetics of TLS formation that are continuously reported in the clinic.We used herein two distinct murine models of pulmonary inflammation, relying on orthotopic lung tumor implantation, or intranasal administration of bacterial products, to generate TLS formation within mouse lung tissue. This review compares different workflows aiming at the detection and quantification of TLS using automated image analysis and artificial intelligence-assisted tissue classification. We also describe different methods for partitioning serial sections, depending on the tissue morphology and the experimental goal.

An Introduction to Tertiary Lymphoid Structures in Cancer

Immunotherapy has revolutionized therapeutics for cancer patients, which signifies the importance of effective antitumor immunity in combatting cancer. However, the benefit of immunotherapies is limited to specific patient populations and tumor types, suggesting the overt need for new immunotherapeutic targets. Tertiary lymphoid structures (TLS) are ectopic lymph node-like structures that develop at the sites of chronic inflammation such as cancer. TLS are correlated with favorable clinical outcomes across multiple solid tumors and are associated with increased tumor-infiltrating lymphocytes (TILs), particularly effector memory CD8+ T cells. Despite strong clinical data in humans, there are still major knowledge gaps on the function of TLS in cancer. Herein, we highlight the known biology and clinical impact of TLS, which offer further evidence to harness TLS for improved immunotherapeutics.

Nano-fluorescence imaging: advancing lymphatic disease diagnosis and monitoring

The lymphatic system plays a crucial role in maintaining physiological homeostasis and regulating immune responses. Traditional imaging modalities such as magnetic resonance imaging, computerized tomography, and positron emission tomography have been widely used to diagnose disorders in the lymphatic system, including lymphedema, lymphangioma, lymphatic metastasis, and Castleman disease. Nano-fluorescence technology has distinct advantages-including naked-eye visibility, operational simplicity, portability of the laser, and real-time visibility-and serves as an innovative alternative to traditional imaging techniques. This review explores recent advancements in nano-fluorescence imaging aimed at enhancing the resolution of lymphatic structure, function, and immunity. After delineating the fundamental characteristics of lymphatic systems, it elaborates on the development of various nano-fluorescence systems (including nanoparticles incorporating fluorescent dyes and those with intrinsic fluorescence) while addressing key challenges such as photobleaching, limited tissue penetration, biocompatibility, and signal interference from biomolecules. Furthermore, this review highlights the clinical applications of nano-fluorescence and its potential integration into standard diagnostic protocols. Ongoing advancements in nanoparticle technology underscore the potential of nano-fluorescence to revolutionize the diagnosis and treatment of lymphatic disease.

Leveraging the synergy between anti-angiogenic therapy and immune checkpoint inhibitors to treat digestive system cancers

The response rates to immunotherapy vary widely depending on the type of cancer and the specific treatment used and can be disappointingly low for many solid tumors. Fortunately, due to their complementary mechanisms of action, immunotherapy and anti-angiogenic therapy have synergistic effects in cancer treatment. By normalizing the tumor vasculature, anti-angiogenic therapy can improve blood flow and oxygenation to facilitate better immune cell infiltration into the tumor and enhance the effectiveness of immunotherapy. It also reduces immunosuppressive factors and enhances immune activation, to create a more favorable environment for immune cells to attack the tumor. Their combination leverages the strengths of both therapies to enhance anti-tumor effects and improve patient outcomes. This review discusses the vasculature-immunity crosstalk in the tumor microenvironment and summarizes the latest advances in combining anti-angiogenic therapy and immune checkpoint inhibitors to treat digestive system tumors.

Co-expression network and survival analysis of breast cancer inflammation and immune system hallmark genes

The tertiary lymphoid structure (TLS) plays a central role in cancer immune response, and its gene expression pattern, called the TLS signature, has shown prognostic value in breast cancer. The formation of TLS and tumor-associated high endothelial venules (TA-HEVs), responsible for lymphocytic infiltration within the TLS, is associated with the expression of cancer hallmark genes (CHGs) related to immunity and inflammation. In this study, we performed co-expression network analysis of immune- and inflammation-related CHGs to identify predictive genes for breast cancer. In total, 382 immune- and inflammation-related CHGs with high expression variance were extracted from the GSE86166 microarray dataset of patients with breast cancer. CHGs were classified into five modules by applying weighted gene co-expression network analysis. The survival analysis results for each module showed that one module comprising 45 genes was statistically significant for relapse-free and overall survival. Four network properties identified key genes in this module with high prognostic prediction abilities: CD34, CXCL12, F2RL2, JAM2, PROS1, RAPGEF3, and SELP. The prognostic accuracy of the seven genes in breast cancer was synergistic and exceeded that of other predictors in both small and large public datasets. Enrichment analysis predicted that these genes had functions related to leukocyte infiltration of TA-HEVs. There was a positive correlation between key gene expression and the TLS signature, suggesting that gene expression levels are associated with TLS density. Co-expression network analysis of inflammation- and immune-related CHGs allowed us to identify genes that share a standard function in cancer immunity and have a high prognostic predictive value. This analytical approach may contribute to the identification of prognostic genes in TLS.

Tertiary lymphoid structures in the central nervous system

Tertiary lymphoid structures (TLSs) frequently occur at sites of chronic inflammation. A more advanced stage of multiple sclerosis (MS) has been associated with certain TLSs. However, tumor-associated TLSs have been shown to correlate with a greater treatment response rate and a better prognosis in glioma mouse models. In this review, we evaluate the clinical significances of TLSs in prognosis and treatment response, as well as the status of TLS-directed therapies targeting alternative biochemical pathways in various central nervous system (CNS) disorders. Potential molecular mechanisms underlying the development of TLSs are also discussed. Exploring these areas may provide an essential understanding of the processes behind disease advancement, uncover new therapeutic objectives, and detect biomarkers that forecast disease progression and treatment efficacy.

Global trends in tertiary lymphoid structures: a bibliometric analysis from 2014 to 2023

AIM AND BACKGROUND

Tertiary lymphoid structures (TLS) are increasingly recognized for their role in immunity. Despite growing interest, a systematic bibliometric analysis of TLS-related research has been lacking. To provide a comprehensive overview of current research trends and hotspots, we conducted a bibliometric analysis using data from the Web of Science Core Collection.

METHODS

We retrieved TLS-related publications from the Science Citation Index Expanded within the Web of Science Core Collection from January 2014 to December 2023. Co-occurrence analysis with "VOSviewer" identified current status and research hotspots, while "CiteSpace" was used for co-citation analysis to assess knowledge evolution and bursts. Thematic evolution was explored using bibliometrics to identify emerging keyword trends. Additionally, we examined country/region, institutional, and author contributions and collaborations. Tables were created using Microsoft Word.

RESULTS

A total of 785 publications were analyzed, showing a continuous growth trend from 2017 to 2023, indicating escalating interest in TLS among researchers. Leading countries in TLS research were China (231 publications), the United States (212 publications), and France (89 publications). The most productive institution and author were the "Institut national de la santé et de la recherche médicale" (70 publications) and Catherine Sautes-Fridman (21 publications), respectively. Key topics included TLS, B cells, and immunotherapy. Recent research has focused on mechanisms linking TLS with cancers, such as immunotherapy, tumor microenvironment, tumor-infiltrating lymphocytes, prognosis, and immune checkpoint inhibitors, highlighting an expanding area of study. Additionally, TLS' potential as a biomarker for predicting immunotherapy efficacy across different cancer types remains a burgeoning research direction.

CONCLUSIONS

This study provides a comprehensive analysis of global TLS-related publications, revealing key literature metrics and identifying influential articles and emerging research concerns. These findings contribute valuable insights into the role of TLS in immunotherapy and suggest future directions for this dynamic field.

Histopathological Correlation Between High Endothelial Venule Neogenesis and the Tumor Microenvironment in Lung Adenocarcinoma

BACKGROUND/AIM

The dynamic interplay between cancer cells and the microenvironment involves a wide range of intricate relationships that evolve during different stages of tumor progression. Recent attention has focused on high endothelial venules (HEVs), specialized endothelial cells in tumors with a unique cuboidal shape similar to those in lymph nodes. Previous animal studies have shown that normalization of tumor angiogenesis through anti-VEGFR2 therapy promotes HEV formation. However, few reports exist regarding the relationship between HEVs and preexisting blood vessels or interstitial fibers. In this study, we histologically examined whether tumor vascular structure correlates with HEV neogenesis.

PATIENTS AND METHODS

A total of 109 patients with pathological stage I lung adenocarcinoma who had undergone curative lung resection at our Institute between 2012 and 2016 were included. HEVs were identified by anti-peripheral node addressin (PNAd) staining. Immunostaining and Elastica-Masson-Goldner staining were performed on tumor sections and quantified.

RESULTS

PNAd-positive cells were identified in 102 (93.6%) patients. Nearly all PNAd-positive cells were located within or near immune cell clusters. We investigated the correlation between microvessel structures or interstitial fibers and the number/density of PNAd-positive vessels, but no significant correlation was found. Since PNAd-positive cells were concentrated in immune cell aggregates, we focused our analysis specifically on these regions. Immune cell aggregates with abundant PNAd-positive vessels had a greater microvessel density along with by rich collagen fiber production, and displayed a more mature morphological phenotype of HEVs.

CONCLUSION

The generation of PNAd-positive cells in tumors is governed by an angiogenetic mechanism distinct from that of broader tumor microenvironment. Furthermore, the accumulation of immune cells is associated with increased HEV maturation.

The immune landscape in apical periodontitis: From mechanism to therapy

Apical periodontitis (AP) is featured by a persistent inflammatory response and alveolar bone resorption initiated by microorganisms, posing risks to both dental and systemic health. Nonsurgical endodontic treatment is the recommended treatment plan for AP with a high success rate, but in some cases, periapical lesions may persist despite standard endodontic treatment. Better comprehension of the AP inflammatory microenvironment can help develop adjunct therapies to improve the outcome of endodontic treatment. This review presents an overview of the immune landscape in AP, elucidating how microbial invasion triggers host immune activation and shapes the inflammatory microenvironment, ultimately impacting bone homeostasis. The destructive effect of excessive immune activation on periapical tissues is emphasized. This review aimed to systematically discuss the immunological basis of AP, the inflammatory bone resorption and the immune cell network in AP, thereby providing insights into potential immunotherapeutic strategies such as targeted therapy, antioxidant therapy, adoptive cell therapy and cytokine therapy to mitigate AP-associated tissue destruction.

Tertiary lymphoid structures as potential biomarkers for cancer prediction and prognosis

Tertiary lymphoid structures (TLSs) are ectopic lymphocyte aggregates formed in non-lymphoid tissues, including cancers, and are loci for the generation of in situ anti-tumor immune responses, which play a crucial role in cancer control. The state of TLS presence in cancer and its composition can significantly impact the treatment response and prognosis of patients. TLSs have the potential to serve as predictive and prognostic biomarkers for cancer. However, the mechanisms underlying TLS formation in cancer and how the essential components of TLSs affect cancer are not fully understood. In this review, we summarized TLS formation in cancer, the value of the TLS in different states of existence, and its key constituents for cancer prediction and prognosis. Finally, we discussed the impact of cancer treatment on TLSs.

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.

Tertiary lymphoid structures in diseases: immune mechanisms and therapeutic advances

Tertiary lymphoid structures (TLSs) are defined as lymphoid aggregates formed in non-hematopoietic organs under pathological conditions. Similar to secondary lymphoid organs (SLOs), the formation of TLSs relies on the interaction between lymphoid tissue inducer (LTi) cells and lymphoid tissue organizer (LTo) cells, involving multiple cytokines. Heterogeneity is a distinguishing feature of TLSs, which may lead to differences in their functions. Growing evidence suggests that TLSs are associated with various diseases, such as cancers, autoimmune diseases, transplant rejection, chronic inflammation, infection, and even ageing. However, the detailed mechanisms behind these clinical associations are not yet fully understood. The mechanisms by which TLS maturation and localization affect immune function are also unclear. Therefore, it is necessary to enhance the understanding of TLS development and function at the cellular and molecular level, which may allow us to utilize them to improve the immune microenvironment. In this review, we delve into the composition, formation mechanism, associations with diseases, and potential therapeutic applications of TLSs. Furthermore, we discuss the therapeutic implications of TLSs, such as their role as markers of therapeutic response and prognosis. Finally, we summarize various methods for detecting and targeting TLSs. Overall, we provide a comprehensive understanding of TLSs and aim to develop more effective therapeutic strategies.

Dynamics of Endothelial Cell Diversity and Plasticity in Health and Disease

Endothelial cells (ECs) are vital structural units of the cardiovascular system possessing two principal distinctive properties: heterogeneity and plasticity. Endothelial heterogeneity is defined by differences in tissue-specific endothelial phenotypes and their high predisposition to modification along the length of the vascular bed. This aspect of heterogeneity is closely associated with plasticity, the ability of ECs to adapt to environmental cues through the mobilization of genetic, molecular, and structural alterations. The specific endothelial cytoarchitectonics facilitate a quick structural cell reorganization and, furthermore, easy adaptation to the extrinsic and intrinsic environmental stimuli, known as the epigenetic landscape. ECs, as universally distributed and ubiquitous cells of the human body, play a role that extends far beyond their structural function in the cardiovascular system. They play a crucial role in terms of barrier function, cell-to-cell communication, and a myriad of physiological and pathologic processes. These include development, ontogenesis, disease initiation, and progression, as well as growth, regeneration, and repair. Despite substantial progress in the understanding of endothelial cell biology, the role of ECs in healthy conditions and pathologies remains a fascinating area of exploration. This review aims to summarize knowledge and concepts in endothelial biology. It focuses on the development and functional characteristics of endothelial cells in health and pathological conditions, with a particular emphasis on endothelial phenotypic and functional heterogeneity.

Intratumoral high endothelial venules in solid tumors: a pooled study

Objective

We performed this pooled analysis for the first time to comprehensively explore the prognostic value of tumor-associated high endothelial venules (TA-HEVs) and determine their relationships with clinicopathological features in solid tumors.

Methods

Four online databases, including PubMed, Web of Science, Embase, and Cochrane Library, were comprehensively searched to identify studies assessing the effect of TA-HEVs on prognosis or clinicopathological features. Hazard ratios (HRs) with 95% confidence intervals (CIs) were applied to evaluate survival outcomes, including overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), and cancer-specific survival (CSS). The association between TA-HEV status and clinicopathological characteristics was assessed by odds ratios (ORs) combined with 95% CIs. Subgroup analysis was conducted to explore sources of heterogeneity. The sensitivity analysis was performed to evaluate the stability of our findings. Meanwhile, Funnel plots were employed to visually evaluate potential publication bias, and both Begg's and Egger's tests were adopted to quantitatively determine publication bias.

Results

A total of 13 retrospective cohort studies, involving 1,933 patients were finally included in this meta-analysis. Effect-size pooling analysis showed that the positivity of TA-HEVs was related to improved OS (pooled HR: 0.75, 95% CI: 0.62-0.93, P<0.01), and DFS (pooled HR = 0.54, 95% CI = 0.41-0.72, P< 0.01). However, TA-HEV positivity in solid tumors was not linked to PFS (pooled HR = 0.75, 95% CI 0.34-1.64, P = 0.47) or CSS (pooled HR: 0.58, 95% CI: 0.04-7.58, P= 0.68). Further subgroup analysis demonstrated that ethnicity and source of HR were the main factors contributing to heterogeneity. Moreover, TA-HEVs were inversely associated with lymph node metastasis and distant metastasis, but were positively related to worse tumor differentiation. However, TA-HEVs were not significantly correlated with sex, LVI, clinical stage, and depth of invasion. Sensitivity analysis suggested that the pooled results were stable and reliable, with no significant publication bias in all included articles.

Conclusions

This is the first comprehensive analysis of the prognostic value of TA-HEVs in solid tumors using existing literature. Overall, our study demonstrated a significant correlation between TA-HEVs and prognosis as well as clinicopathological features. TA-HEVs may serve as novel immune-related biomarkers for clinical assessments and prognosis prediction in solid tumors.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php, identifier CRD42023394998.

Development and organization of omental milky spots

The milky spots in omentum are atypical lymphoid tissues that play a pivotal role in regulating immune responses in the peritoneal cavity. The milky spots act as central hubs for collecting antigens and particles from the peritoneal cavity, regulating lymphocyte trafficking, promoting the differentiation and self-renewal of immune cells, and supporting the local germinal centre response. In addition, the milky spots exhibit unique developmental characteristics that combine the features of secondary and tertiary lymphoid tissues. These structures are innately programmed to form during foetal development; however, they can also be formed postnatally in response to peritoneal irritation such as inflammation, infection, obesity, or tumour metastasis. In this review, I discuss emerging perspectives on homeostatic development and organization of the milky spots.

Mapping the complexity and diversity of tertiary lymphoid structures in primary and peritoneal metastatic gastric cancer

BACKGROUND

Tertiary lymphoid structures (TLSs) are thought to stimulate antitumor immunity and positively impact prognosis and response to immune checkpoint blockade. In gastric cancers (GCs), however, TLSs are predominantly found in GC with poor prognosis and limited treatment response. We, therefore, hypothesize that immune cell composition and function of TLS depends on tumor location and the tumor immune environment.

METHODS

Spatial transcriptomics and immunohistochemistry were used to characterize the phenotype of CD45+ immune cells inside and outside of TLS using archival resection specimens from GC primary tumors and peritoneal metastases.

RESULTS

We identified significant intrapatient and interpatient diversity of the cellular composition and maturation status of TLS in GC. Tumor location (primary vs metastatic site) accounted for the majority of differences in TLS maturity, as TLS in peritoneal metastases were predominantly immature. This was associated with higher levels of tumor-infiltrating macrophages and Tregs and less plasma cells compared with tumors with mature TLS. Furthermore, mature TLSs were characterized by overexpression of antitumor immune pathways such as B cell-related pathways, MHC class II antigen presentation while immature TLS were associated with protumor pathways, including T cell exhaustion and enhancement of DNA repair pathways in the corresponding cancer.

CONCLUSION

The observation that GC-derived peritoneal metastases often contain immature TLS which are associated with immune suppressive regulatory tumor-infiltrating leucocytes, is in keeping with the lack of response to immune checkpoint blockade and the poor prognostic features of peritoneal metastatic GC, which needs to be taken into account when optimizing immunomodulatory strategies for metastatic GC.

4-nitroquinoline 1-oxide-induced oral epithelial lesions exhibit time- and stage-dependent changes in the tumor immune microenvironment

Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the oral cavity and is associated with high morbidity due to local invasion and lymph node metastasis. Tumor infiltrating lymphocytes (TILs) are associated with good prognosis in oral cancer patients and dictate response to treatment. Ectopic sites for immune activation in tumors, known as tertiary lymphoid structures (TLS), and tumor-associated high-endothelial venules (TA-HEVs), which are specialized lymphocyte recruiting vessels, are associated with a favorable prognosis in OSCC. Why only some tumors support the development of TLS and HEVs is poorly understood. In the current study we explored the infiltration of lymphocyte subsets and the development of TLS and HEVs in oral epithelial lesions using the 4-nitroquinoline 1-oxide (4NQO)-induced mouse model of oral carcinogenesis. We found that the immune response to 4NQO-induced oral epithelial lesions was dominated by T cell subsets. The number of T cells (CD4+, FoxP3+, and CD8+), B cells (B220+) and PNAd+ HEVs increased from the earliest to the latest endpoints. All the immune markers increased with the severity of the dysplasia, while the number of HEVs and B cells further increased in SCCs. HEVs were present already in early-stage lesions, while TLS did not develop at any timepoint. This suggests that the 4NQO model is applicable to study the dynamics of the tumor immune microenvironment at early phases of oral cancer development, including the regulation of TA-HEVs in OTSCC.

An autophagy program that promotes T cell egress from the lymph node controls responses to immune checkpoint blockade

Lymphatic endothelial cells (LECs) of the lymph node (LN) parenchyma orchestrate leukocyte trafficking and peripheral T cell dynamics. T cell responses to immunotherapy largely rely on peripheral T cell recruitment in tumors. Yet, a systematic and molecular understanding of how LECs within the LNs control T cell dynamics under steady-state and tumor-bearing conditions is lacking. Intravital imaging combined with immune phenotyping shows that LEC-specific deletion of the essential autophagy gene Atg5 alters intranodal positioning of lymphocytes and accrues their persistence in the LNs by increasing the availability of the main egress signal sphingosine-1-phosphate. Single-cell RNA sequencing of tumor-draining LNs shows that loss of ATG5 remodels niche-specific LEC phenotypes involved in molecular pathways regulating lymphocyte trafficking and LEC-T cell interactions. Functionally, loss of LEC autophagy prevents recruitment of tumor-infiltrating T and natural killer cells and abrogates response to immunotherapy. Thus, an LEC-autophagy program boosts immune-checkpoint responses by guiding systemic T cell dynamics.

Mathematical modeling of endogenous and exogenously administered T cell recirculation in mouse and its application to pharmacokinetic studies of cell therapies

Introduction

In vivo T cell migration has been of interest to scientists for the past 60 years. T cell kinetics are important in the understanding of the immune response to infectious agents. More recently, adoptive T cell therapies have proven to be a most promising approach to treating a wide range of diseases, including autoimmune and cancer diseases, whereby the characterization of cellular kinetics represents an important step towards the prediction of therapeutic efficacy.

Methods

Here, we developed a physiologically-based pharmacokinetic (PBPK) model that describes endogenous T cell homeostasis and the kinetics of exogenously administered T cells in mouse. Parameter calibration was performed using a nonlinear fixed-effects modeling approach based on published data on T cell kinetics and steady-state levels in different tissues of mice. The Partial Rank Correlation Coefficient (PRCC) method was used to perform a global sensitivity assessment. To estimate the impact of kinetic parameters on exogenously administered T cell dynamics, a local sensitivity analysis was conducted.

Results

We simulated the model to analyze cellular kinetics following various T cell doses and frequencies of CCR7+ T cells in the population of infused lymphocytes. The model predicted the effects of T cell numbers and of population composition of infused T cells on the resultant concentration of T cells in various organs. For example, a higher percentage of CCR7+ T cells among exogenously administered T lymphocytes led to an augmented accumulation of T cells in the spleen. The model predicted a linear dependence of T cell dynamics on the dose of adoptively transferred T cells.

Discussion

The mathematical model of T cell migration presented here can be integrated into a multi-scale model of the immune system and be used in a preclinical setting for predicting the distribution of genetically modified T lymphocytes in various organs, following adoptive T cell therapies.

Tertiary lymphoid structures associated with enhanced anti-tumor immunity and favorable prognosis in cervical squamous carcinoma

BACKGROUND

Cervical squamous carcinoma (CESC) is the main subtype of cervical cancer. Unfortunately, there are presently no effective treatment options for advanced and recurrent CESC. Tertiary lymphoid structures (TLSs) are clusters of lymphoid cells that resemble secondary lymphoid organs; nevertheless, there is no summary of the clinical importance of TLS in CESC.

METHODS

A large set of transcriptomic and single-cell RNA-sequencing (scRNA-seq) datasets were used to analyze the pattern of TLS and its immuno-correlations in CESC. Additionally, an independent in-house cohort was collected to validate the correlation between TLS and TME features.

RESULTS

In the current study, we found that the presence of TLS could predict better prognosis in CESC and was correlated with the activation of immunological signaling pathways and enrichment of immune cell subpopulations. In addition, TLS was associated with reduced proliferation activity in tumor cells, indicating the negative correlation between TLS and the degree of malignancy. Last but not least, in two independent immunotherapy cohorts, tumors with the presence of TLS were more sensitive to immunotherapy.

CONCLUSION

Overall, TLS is related to an inflamed TME and identified immune-hot tumors, which could be an indicator for the identification of immunological features in CESC.

Advances in the study of tertiary lymphoid structures in the immunotherapy of breast cancer

Breast cancer, as one of the most common malignancies in women, exhibits complex and heterogeneous pathological characteristics across different subtypes. Triple-negative breast cancer (TNBC) and HER2-positive breast cancer are two common and highly invasive subtypes within breast cancer. The stability of the breast microbiota is closely intertwined with the immune environment, and immunotherapy is a common approach for treating breast cancer.Tertiary lymphoid structures (TLSs), recently discovered immune cell aggregates surrounding breast cancer, resemble secondary lymphoid organs (SLOs) and are associated with the prognosis and survival of some breast cancer patients, offering new avenues for immunotherapy. Machine learning, as a form of artificial intelligence, has increasingly been used for detecting biomarkers and constructing tumor prognosis models. This article systematically reviews the latest research progress on TLSs in breast cancer and the application of machine learning in the detection of TLSs and the study of breast cancer prognosis. The insights provided contribute valuable perspectives for further exploring the biological differences among different subtypes of breast cancer and formulating personalized treatment strategies.

Discovery of an independent poor-prognosis subtype associated with tertiary lymphoid structures in breast cancer

Introduction

Tertiary lymphoid structures (TLSs) are ectopic lymphoid formations that arise in non-lymphoid tissues due to chronic inflammation. The pivotal function of TLSs in regulating tumor invasion and metastasis has been established across several cancers, such as lung cancer, liver cancer, and melanoma, with a positive correlation between increased TLS presence and improved prognosis. Nevertheless, the current research about the clinical significance of TLSs in breast cancer remains limited.

Methods

In our investigation, we discovered TLS-critical genes that may impact the prognosis of breast cancer patients, and categorized breast cancer into three distinct subtypes based on critical gene expression profiles, each exhibiting substantial differences in prognosis (p = 0.0046, log-rank test), with Cluster 1 having the best prognosis, followed by Cluster 2, and Cluster 3 having the worst prognosis. We explored the impact of the heterogeneity of these subtypes on patient prognosis, the differences in the molecular mechanism, and their responses to drug therapy and immunotherapy. In addition, we designed a machine learning-based classification model, unveiling highly consistent prognostic distinctions in several externally independent cohorts.

Results

A notable marker gene CXCL13 was identified in Cluster 3, potentially pivotal in enhancing patient prognosis. At the single-cell resolution, we delved into the adverse prognosis of Cluster 3, observing an enhanced interaction between fibroblasts, myeloid cells, and basal cells, influencing patient prognosis. Furthermore, we identified several significantly upregulated genes (CD46, JAG1, IL6, and IL6R) that may positively correlate with cancer cells' survival and invasive capabilities in this subtype.

Discussion

Our study is a robust foundation for precision medicine and personalized therapy, presenting a novel perspective for the contemporary classification of breast cancer.

A distinct tumor microenvironment makes anaplastic thyroid cancer more lethal but immunotherapy sensitive than papillary thyroid cancer

Both anaplastic thyroid cancer (ATC) and papillary thyroid cancer (PTC) originate from thyroid follicular epithelial cells, but ATC has a significantly worse prognosis and shows resistance to conventional therapies. However, clinical trials found that immunotherapy works better in ATC than late-stage PTC. Here, we used single-cell RNA sequencing (scRNA-Seq) to generate a single-cell atlas of thyroid cancer. Differences in ATC and PTC tumor microenvironment components (including malignant cells, stromal cells, and immune cells) leading to the polarized prognoses were identified. Intriguingly, we found that CXCL13+ T lymphocytes were enriched in ATC samples and might promote the development of early tertiary lymphoid structure (TLS). Last, murine experiments and scRNA-Seq analysis of a treated patient's tumor demonstrated that famitinib plus anti-PD-1 antibody could advance TLS in thyroid cancer. We displayed the cellular landscape of ATC and PTC, finding that CXCL13+ T cells and early TLS might make ATC more sensitive to immunotherapy.

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.

The Chimera of TPGS and Nanoscale Lipid Carriers as Lymphatic Drug Delivery Vehicles to Fight Metastatic Cancers

The lymphatic system (LS) plays a crucial role in fluid balance, transportation of macromolecules, and immune response. Moreover, LS is a channel for microbial invasion and cancer metastasis. Particularly, solid tumors, including lung, breast, melanoma, and prostate cancers, are metastasized across highways of LS. Subsequently, the fabrication of chimeric lymphatic drug delivery systems (LDDS) is a promising strategy to fight cancer metastasis and control microbial pandemics. In this regard, LDDS, in terms of PEG-nanoscaled lipid carriers, elicited a revolution during the COVID-19 pandemic as cargoes for mRNA vaccines. The drug delivered by the lymphatic pathway escapes first-pass metabolism and enhances the drug's bioavailability. Ample approaches, including synthesis of prodrugs, trigging of chylomicron biosynthesis, and fabrication of nanocarriers, facilitate lymphatic drug delivery. Specifically, nanoscales lipid cargoes have the propensity to lymphatic trafficking. Interestingly, TPGSengineered nanoscale lipid cargoes enhance lymphatic trafficking, increase tissue permeation, and, specifically, uptake. Moreover, they overcome biological barriers, control biodistribution, and enhance organelles localization. Most anticancer agents are non-specific, have low bioavailability, and induced drug resistance. Therefore, TPGS-engineered nanoscale lipid chimeras improve the therapeutic impact of anticancer agents. This review highlights lymphatic cancer metastasis, nanoscales lipid cargoes as LDDS, and their influence on lymphatic trafficking, besides the methods of LDD studies.

Advances in Predictive Biomarkers for Anti-Angiogenic Therapy in Non-Small Cell Lung Cancer

This study aimed to explore advances in biomarkers related to anti-angiogenic therapy in patients with non-small cell lung cancer (NSCLC), thereby enhancing treatment selection, advancing personalized and precision medicine to improve treatment outcomes and patient survival rates. This article reviews key discoveries in predictive biomarkers for anti-angiogenic therapy in NSCLC in recent years, such as (1) liquid biopsy predictive biomarkers: studies have identified activated circulating endothelial cells (aCECs) via liquid biopsy as potential predictive biomarkers for the efficacy of anti-angiogenic therapy; (2) imaging biomarkers: advanced imaging technologies, such as dynamic contrast-enhanced integrated magnetic resonance positron emission tomography (MR-PET), are used to assess tumor angiogenesis in patients with NSCLC and evaluate the clinical efficacy of anti-angiogenic drugs; (3) genetic predictive biomarkers: research has explored polymorphisms of Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1) and vascular endothelial growth factor-A (VEGF-A), as well as how plasma levels of VEGF-A can predict the outcomes and prognosis of patients with non-squamous NSCLC undergoing chemotherapy combined with bevacizumab. Despite progress in identifying biomarkers related to anti-angiogenic therapy, several challenges remain, including limitations in clinical trials, heterogeneity in NSCLC, and technical hurdles. Future research will require extensive clinical validation and in-depth mechanistic studies to fully exploit the potential of these biomarkers for personalized treatment.

Heterogeneity of tertiary lymphoid structures in cancer

The success of immunotherapy approaches, such as immune checkpoint blockade and cellular immunotherapy with genetically modified lymphocytes, has firmly embedded the immune system in the roadmap for combating cancer. Unfortunately, the majority of cancer patients do not yet benefit from these therapeutic approaches, even when the prognostic relevance of the immune response in their tumor entity has been demonstrated. Therefore, there is a justified need to explore new strategies for inducing anti-tumor immunity. The recent connection between the formation of ectopic lymphoid aggregates at tumor sites and patient prognosis, along with an effective anti-tumor response, suggests that manipulating the occurrence of these tertiary lymphoid structures (TLS) may play a critical role in activating the immune system against a growing tumor. However, mechanisms governing TLS formation and a clear understanding of their substantial heterogeneity are still lacking. Here, we briefly summarize the current state of knowledge regarding the mechanisms driving TLS development, outline the impact of TLS heterogeneity on clinical outcomes in cancer patients, and discuss appropriate systems for modeling TLS heterogeneity that may help identify new strategies for inducing protective TLS formation in cancer patients.

High endothelial venule is a prognostic immune-related biomarker in patients with resected intrahepatic cholangiocarcinoma

Having been reported to be a crucial prognostic factor in solid tumours, the role of high endothelial venule (HEV) in intrahepatic cholangiocarcinoma (ICC) remains unclear, however. The data of ICC and healthy individuals were downloaded from the Gene Expression Omnibus (GEO), and The Cancer Genome Atlas (TCGA) databases. Meanwhile, a cutting-edge ICC high-resolution spatial transcriptome was also acquired before these data were comprehensively analysed using bioinformatics approaches. Moreover, 95 individuals with ICC who had undergone resection surgery were enrolled in this study to investigate the relationship between HEV and tumour microenvironment (TME) applying immunohistochemistry and multiple immunofluorescence techniques. The high-HEV subtype contains rich immune infiltrates including tertiary lymphoid structure (TLS), CD8+ T cells, and CD20+ B cells. Furthermore, HEV and TLS exhibited a strong relationship of spatial colocalization. Correlated with improved prognostic outcomes in ICC, the high-HEV subtype could be an independent prognostic indicator for individuals with ICC. This study revealed the association of HEV with immune function and observed a strong spatial colocalization correlation between HEV and TLS. Moreover, correlated with immunotherapeutic response, HEV could improve prognostic outcomes, which may be a potential indicator of immunotherapy pathology in ICC.

High endothelial venules predict response to PD-1 inhibitors combined with anti-angiogenesis therapy in NSCLC

Tumor-associated high endothelial venules (TA-HEVs) mediate lymphocyte entry into tumors. Therefore, combined anti-angiogenesis therapy and programmed death-1 (PD-1) inhibitors might stimulate tumor immunity. This study will explore the TA-HEVs and real-world data of the combination therapy in non-small cell lung cancer (NSCLC). Firstly, we found a certain relationship between HEVs and immune effector cells by multiple immunofluorescence staining. We then analyzed the efficacy of immunotherapy combined with anti-angiogenesis therapy in advanced NSCLC patients by collecting real-world clinical data. Finally, we explored the predictive value of HEVs in combination therapy by analyzing pre-treatment pathological slides of patients with multiple immunofluorescence and RNA sequencing. Immunofluorescence staining of high endothelial venules (PNAd+) reveals that the frequency of HEVs is positively correlated with tumor-infiltrating stem-like CD8+ T cells (TCF-1+PD-1+) in the TME of advanced NSCLC patients (P = 0.0221). We retrospectively analyzed the efficacy of 96 patients with advanced NSCLC who received PD-1 inhibitors combined with anti-angiogenesis therapy in the real-world. The median PFS of patients combined with anti-angiogenesis therapy was longer than that of patients without anti-angiogenesis therapy (9.7 vs 8.6 months, P = 0.041). Multiple immunofluorescence staining of tumor biopsies before treatment from 14 patients with advanced NSCLC reveals that PNAd+ is predictive of better response and survival upon PD-1 inhibitors combined with anti-angiogenesis therapy (P = 0.0274). In addition, we collected peripheral blood from an effective group of patients for RNA sequencing and found that immune cells activation-related gene expression scores were higher. Combined anti-angiogenic and anti-PD-1 therapy stimulates tumor immunity through TA-HEVs formation. TA-HEVs not only mediate immune cell entry into tumors, but also are associated with the efficacy of PD-1 inhibitors and anti-angiogenesis therapy in NSCLC.

Tertiary Lymphoid Structures Are Related to Inflammatory Progression and Bone Loss in Human Apical Periodontitis

INTRODUCTION

Bone loss is strongly associated with the immunologic milieu in apical periodontitis (AP). Tertiary lymphoid structures (TLSs) are organized lymphoid cell aggregates that form in nonlymphoid tissues under persistent inflammatory circumstances. To date, there has been no relevant report of TLSs in periapical lesions. This work aimed to investigate the formation and potential function of TLSs in AP.

METHODS

Tissues from human apical lesions (n = 61) and healthy oral mucosa (n = 5) were collected. Immunohistochemistry and multiplex immunofluorescence were used to detect the formation of TLSs. Correlation analyses were performed between clinical variables and TLSs. In addition, immunohistochemistry was used to evaluate the expression of interleukin-1 beta, interleukin-6, receptor activator of nuclear factor kappa-B ligand, and macrophage subsets in the apical lesions.

RESULTS

Periapical granulomas (n = 24) and cysts (n = 37) were identified by histologic evaluation. TLSs, composed of B-cell and T-cell clusters, developed in periapical granulomas and radicular cysts. The CXC-chemokine ligand 13, its receptor CXC-chemokine receptor 5, follicular dendritic cells, and high endothelial venules were localized in TLSs. The quantity and size of TLSs were positively associated with bone loss in AP. Moreover, proinflammatory cytokines and macrophage subsets were also substantially elevated in TLS regions of apical lesions.

CONCLUSIONS

The formation of TLSs in periapical granulomas and cysts was closely associated with persistent immune responses and bone loss in apical lesions. TLSs provide an updated insight into the complicated immune response process in AP.

Harnessing the power of oncolytic virotherapy and tertiary lymphoid structures to amplify antitumor immune responses in cancer patients

Tertiary lymphoid structures (TLS) are ectopic aggregates of immune cells that develop in non-lymphoid tissues under persistent inflammation. Since their presence has been associated with a better prognosis in cancer patients, modulating TLS formation is being part of new challenges in immunotherapy. Although mechanisms underlying TLS genesis are still not fully understood, different strategies have been developed in preclinical models to induce their formation and ultimately enhance antitumor responses. Herein, we will discuss a new approach that would consist in using oncolytic viruses (OV). These viruses have the unique feature to preferentially infect, replicate in and kill cancer cells. Their immunoadjuvant property, their use as a vector of therapeutic molecules and their selectivity for cancer cells, make them an attractive strategy to induce TLS in the tumor microenvironment. This review will examine the current knowledge about TLS neogenesis, approaches for inducing them, and relevance of using OV for this purpose, especially in combination with immunotherapy such as immune checkpoint blockade.

Melanoma-derived mediators can foster the premetastatic niche: crossroad to lymphatic metastasis

The natural history of advanced malignant melanoma demonstrates that, in most cases, widespread tumor dissemination is preceded by regional metastases involving tumor-draining lymph nodes [sentinel lymph nodes (SLNs)]. Under physiological conditions, LNs play a central role in immunosurveillance to non-self-antigens to which they are exposed via afferent lymph. The dysfunctional immunity in SLNs is mediated by tumor secretory factors that allow the survival of metastatic melanoma cells within the LN by creating a premetastatic niche (PMN). Recent studies outline the altered microenvironment of LNs shaped by melanoma mediators. Here, we discuss tumor secretory factors involved in subverting tumor immunity and remodeling LNs and highlight emerging therapeutic strategies to reinvigorate antitumoral immunity in SLNs.

Tertiary Lymphoid Structures (TLSs) and Stromal Blood Vessels Have Significant and Heterogeneous Impact on Recurrence, Lymphovascular and Perineural Invasion amongst Breast Cancer Molecular Subtypes

BACKGROUND

Tertiary lymphoid structures (TLSs) mediate local antitumor immunity, and interest in them significantly increased since cancer immunotherapy was implemented. We examined TLS- tumor stromal blood vessel interplay for each breast cancer (BC) molecular subtype related to recurrence, lymphovascular invasion (LVI), and perineural invasion (PnI).

METHODS

TLSs were quantified on hematoxylin and eosin stain specimens followed by CD34/smooth muscle actin (SMA) double immunostaining for stromal blood vessel maturation assessment. Statistical analysis linked microscopy to recurrence, LVI, and PnI.

RESULTS

TLS negative (TLS-) subgroups in each BC molecular subtype (except to Luminal A) have higher LVI, PnI, and recurrence. A significant rise in LVI and PnI were observed for the HER2+/TLS- subgroup (p < 0.001). The triple negative breast cancer (TNBC)/TLS- subgroup had the highest recurrence and invasion risk which was also significantly related to tumor grade. PnI but not LVI significantly influenced recurrence in the TNBC/TLS+ subgroup (p < 0.001). TLS-stromal blood vessel interrelation was different amongst BC molecular subtypes.

CONCLUSION

BC invasion and recurrence are strongly influenced by TLS presence and stromal blood vessels, especially for HER2 and TNBC BC molecular subtypes.

High endothelial venules in cancer: Regulation, function, and therapeutic implication

The lack of sufficient intratumoral CD8⁺ T lymphocytes is a significant obstacle to effective immunotherapy in cancer. High endothelial venules (HEVs) are organ-specific and specialized postcapillary venules uniquely poised to facilitate the transmigration of lymphocytes to lymph nodes (LNs) and other secondary lymphoid organs (SLOs). HEVs can also form in human and murine cancer (tumor HEVs [TU-HEVs]) and contribute to the generation of diffuse T cell-enriched aggregates or tertiary lymphoid structures (TLSs), which are commonly associated with a good prognosis. Thus, therapeutic induction of TU-HEVs may provide attractive avenues to induce and sustain the efficacy of immunotherapies by overcoming the major restriction of T cell exclusion from the tumor microenvironment. In this review, we provide current insight into the commonalities and discrepancies of HEV formation and regulation in LNs and tumors and discuss the specific function and significance of TU-HEVs in eliciting, predicting, and aiding anti-tumoral immunity.

Targeting tumor vasculature to improve antitumor activity of T cells armed ex vivo with T cell engaging bispecific antibody

BACKGROUND

Success of T cell immunotherapy hinges on the tumor microenvironment (TME), and abnormal tumor vasculature is a hallmark of most solid tumors and associated with immune evasion. The efficacy of T cell engaging bispecific antibody (BsAb) treatment relies on the successful trafficking and cytolytic activity of T cells in solid tumors. Normalization of tumor vasculature using vascular endothelial growth factor (VEGF) blockades could improve efficacy of BsAb-based T cell immunotherapy.

METHODS

Anti-human VEGF (bevacizumab, BVZ) or anti-mouse VEGFR2 antibody (DC101) was used as VEGF blockade, and ex vivo armed T cells (EATs) carrying anti-GD2, anti-HER2, or anti-glypican3 (GPC3) IgG-(L)-scFv platformed BsAb were used. BsAb-driven intratumoral T cell infiltration and in vivo antitumor response were evaluated using cancer cell line-derived xenografts (CDXs) or patient-derived xenografts (PDXs) carried out in BALB-Rag2 ^-/-IL-2R-γc-KO (BRG) mice. VEGF expression on human cancer cell lines was analyzed by flow cytometry, and VEGF levels in mouse serum were measured using VEGF Quantikine ELISA Kit. Tumor infiltrating lymphocytes (TILs) were evaluated using flow cytometry and by bioluminescence; both TILs and tumor vasculature were studied using immunohistochemistry.

RESULTS

VEGF expression on cancer cell lines increased with seeding density in vitro. BVZ significantly reduced serum VEGF levels in mice. BVZ or DC101 increased high endothelial venules (HEVs) in the TME and substantially enhanced (2.1-8.1 fold) BsAb-driven T cell infiltration into neuroblastoma and osteosarcoma xenografts, which was preferential for CD8(+) TILs versus CD4(+) TILs, leading to superior antitumor effects in multiple CDX and PDX tumor models without added toxicities.

CONCLUSIONS

VEGF blockade using specific antibodies against VEGF or VEGFR2 increased HEVs in the TME and cytotoxic CD8(+) TILs, significantly improving the therapeutic efficacy of EAT strategies in preclinical models, supporting the clinical investigation of VEGF blockades to further enhance BsAb-based T cell immunotherapies.

Tumor Vasculature as an Emerging Pharmacological Target to Promote Anti-Tumor Immunity

Tumor vasculature abnormality creates a microenvironment that is not suitable for anti-tumor immune response and thereby induces resistance to immunotherapy. Remodeling of dysfunctional tumor blood vessels by anti-angiogenic approaches, known as vascular normalization, reshapes the tumor microenvironment toward an immune-favorable one and improves the effectiveness of immunotherapy. The tumor vasculature serves as a potential pharmacological target with the capacity of promoting an anti-tumor immune response. In this review, the molecular mechanisms involved in tumor vascular microenvironment-modulated immune reactions are summarized. In addition, the evidence of pre-clinical and clinical studies for the combined targeting of pro-angiogenic signaling and immune checkpoint molecules with therapeutic potential are highlighted. The heterogeneity of endothelial cells in tumors that regulate tissue-specific immune responses is also discussed. The crosstalk between tumor endothelial cells and immune cells in individual tissues is postulated to have a unique molecular signature and may be considered as a potential target for the development of new immunotherapeutic approaches.

X-ray irradiation negatively affects immune responses in the lymphatic network

Immune checkpoint inhibitor therapy has been attracting attention as a new cancer treatment and is likely to be widely used in combination with radiotherapy. Therefore, examination of the effects of X-ray irradiation on sentinel lymph nodes and lymphatic vessels, which are involved in antigen presentation, is important for therapy. The hindlimbs of mice were irradiated with X-rays (total radiation doses: 2, 10, and 30 Gy), and X-ray computed tomography (CT) imaging was performed using 15-nm or 2-nm gold nanoparticles (AuNPs) as contrast agents on days 7, 14, and 28 after irradiation to evaluate the diameter of the collecting lymph vessels and lymph flow within the irradiated area. X-ray CT imaging data using 15-nm AuNPs on day 28 after irradiation showed that the diameter of the collecting lymph vessels was significantly larger in all irradiated groups compared to the control group (p ≤ 0.01). CT imaging with 2-nm AuNPs showed that lymphatic drainage was significantly reduced in the lymph nodes irradiated with 10 Gy and 30 Gy compared to the lymph nodes irradiated with 2 Gy (p ≤ 0.05). Additionally, immunohistochemical analyses were conducted to evaluate the area density and morphology of high endothelial venules (HEVs) in the lymph nodes, which are important vessels for naive T cells to enter the lymph nodes. The expression level of MECA-79, which specifically localized to HEVs, was significantly decreased in the 10 Gy and 30 Gy irradiation groups compared to the control group (p ≤ 0.05). There was a significant decrease in normal HEV morphology (p ≤ 0.05) and a significant increase in abnormal HEV morphology (p ≤ 0.05) in all irradiated groups. These results also showed that X-ray irradiation induced a time- and radiation dose-dependent increase in the diameter of the collecting lymph vessels, stagnation of intralymphatic lymph flow, and a reduction in the area density of HEVs and their abnormal morphology, demonstrating that X-ray irradiation affected the immune responses. Therefore, these findings suggest that X-ray irradiation to lymph nodes may impair the opportunity for antigen presentation in the lymph nodes, which is the key to cancer immunity, and that for this reason, it is important to carefully plan irradiation of sentinel lymph nodes and develop treatment strategies according to future treatment options.

Hybrid Lymphatic Drug Delivery Vehicles as a New Avenue for Targeted Therapy: Lymphatic Trafficking, Applications, Challenges, and Future Horizons

Lymphatic drug targeting is an effective approach for targeting immunomodulators, and chemotherapeutic drugs at a specific organ or cellular location. The cellular, paracellular, and dendritic cell trafficking machinery are involved in the lymphatic transport of therapeutic agents. The engineering of triggered and hybrid lymphatic drug delivery systems (LDDS) is a promising strategy to fight cancer metastasis and microbial pandemics. Hybrid lymphatic drug delivery systems can be tailored and developed by grafting the conventional LDDS with biological agents. Thus, hybrid LDDS could collect the benefits of conventional and biological delivery systems. Moreover, the fabrication of triggered LDDS increases drug accumulation in the lymphatic system in the response to an internal stimulus such as pH, and redox status or external such as magnetic field, temperature, and light. Stimuli-responsive LDD systems prevent premature release of payload and mediate selective drug biodistribution. This improves therapeutic impact and reduces the systemic side effect of anticancer, immunomodulatory, and antimicrobial therapeutics. This review highlights the challenges and future horizons of nanoscaled-triggered LDDS and their influence on the lymphatic trafficking of therapeutic molecules.

The gene signature of tertiary lymphoid structures within ovarian cancer predicts the prognosis and immunotherapy benefit

Ovarian cancer (OC) has the lowest survival rate among gynecologic malignancies. Ectopic lymphocyte aggregates, namely tertiary lymphoid structures (TLSs), have been reported as positive biomarkers for tumor prognosis. However, the related gene signature of tertiary lymphoid structure in ovarian cancer was less understood. Therefore, this study first exhibited the organizational patterns of tertiary lymphoid structure by H&E staining and immunohistochemistry (IHC), and confirmed the improved survival values of tertiary lymphoid structure and quantified tumor-infiltrating lymphocytes (CD20⁺ B cells and CD8⁺ T cells) in ovarian cancer patients. Secondly, we collected the genes involved in tertiary lymphoid structure from databases. By the univariate regression analysis, the tertiary lymphoid structure gene signature (CETP, CCR7, SELL, LAMP3, CCL19, CXCL9, CXCL10, CXCL11, and CXCL13) with prognostic value, characteristically of ovarian cancer, was constructed in the TCGA dataset and validated in the GSE140082 dataset. Thirdly, by performing CIBERSORT and Tumor Immune Dysfunction and Exclusion (TIDE) analysis, we found that the high expression of this gene signature was positively correlated with developed immune infiltration and reduced immune escape. The improved IPS score and application in the IMvigor210 dataset received PD-L1 proved the predictive value of immunotherapy for this gene signature. Furthermore, this signature showed a better correlation between tumor mutation burden and classical checkpoint genes. In conclusion, Tertiary lymphoid structure plays important role in tumor immunity and the gene signature can be evaluated as a biomarker for predicting prognosis and guiding immunotherapy in ovarian cancer.

Cancer immunotherapies transition endothelial cells into HEVs that generate TCF1+ T lymphocyte niches through a feed-forward loop

The lack of T cell infiltrates is a major obstacle to effective immunotherapy in cancer. Conversely, the formation of tumor-associated tertiary-lymphoid-like structures (TA-TLLSs), which are the local site of humoral and cellular immune responses against cancers, is associated with good prognosis, and they have recently been detected in immune checkpoint blockade (ICB)-responding patients. However, how these lymphoid aggregates develop remains poorly understood. By employing single-cell transcriptomics, endothelial fate mapping, and functional multiplex immune profiling, we demonstrate that antiangiogenic immune-modulating therapies evoke transdifferentiation of postcapillary venules into inflamed high-endothelial venules (HEVs) via lymphotoxin/lymphotoxin beta receptor (LT/LTβR) signaling. In turn, tumor HEVs boost intratumoral lymphocyte influx and foster permissive lymphocyte niches for PD1^- and PD1⁺TCF1⁺ CD8 T cell progenitors that differentiate into GrzB⁺PD1⁺ CD8 T effector cells. Tumor-HEVs require continuous CD8 and NK cell-derived signals revealing that tumor HEV maintenance is actively sculpted by the adaptive immune system through a feed-forward loop.

miR-142 favors naïve B cell residence in peripheral lymph nodes

B lymphocyte development proceeds through a well-ordered sequence of steps, leading to the formation of a sizeable mature B population recognizing a diversity of antigens. These latter cells are ultimately responsible for the production of antibodies upon immune challenges. The detection of threats to the organism is facilitated by the ability of naïve follicular B cells, the main subset of mature B cells in mice, to circulate between lymphoid tissues in search of their cognate antigens. miRNA-mediated fine-tuning of mRNA stability and translation participates in the optimal expression of genetic programs. This regulatory mechanism has been shown to contribute to B cell biology, although the role of individual miRNAs remains understudied. Here, we selectively inactivated the miR-142 locus in B cells. As a consequence, the mature B compartment was visibly perturbed, in agreement with work in miR-142 knockout mice. However, our strategy allowed us to identify roles for the miR-142 locus in B cell physiology obscured by the complexity of the immune phenotype in the null mutant mice. Thus, these miRNAs are necessary for the proper formation of the pre-B cell compartment during development. More remarkably, naïve follicular B cells demonstrated altered migratory properties upon conditional inactivation of the miR-142 locus. The latter mutant cells expressed reduced levels of the homing molecule CD62L. They also migrated more efficiently towards sphingosine-1-phosphate in vitro and displayed an increased abundance of the sphingosine-1-phosphate receptor 1, compatible with improved lymphocyte egress in vivo. In line with these observations, the ablation of the miR-142 locus in B cells caused a paucity of B cells in the lymph nodes. Mutant B cell accumulation in the latter tissues was also compromised upon transfer into a wild-type environment. These changes coincided with suboptimal levels of FOXO1, a positive regulator of CD62L transcription, in mutant B cells. Overall, our findings indicate contributions for the miR-142 locus in various aspects of the B cell life cycle. Notably, this locus appears to favor the establishment of the migratory behavior required for naïve follicular B cell patrolling activity.

Manipulation of the crosstalk between tumor angiogenesis and immunosuppression in the tumor microenvironment: Insight into the combination therapy of anti-angiogenesis and immune checkpoint blockade

Immunotherapy has been recognized as an effective and important therapeutic modality for multiple types of cancer. Nevertheless, it has been increasing recognized that clinical benefits of immunotherapy are less than expected as evidenced by the fact that only a small population of cancer patients respond favorably to immunotherapy. The structurally and functionally abnormal tumor vasculature is a hallmark of most solid tumors and contributes to an immunosuppressive microenvironment, which poses a major challenge to immunotherapy. In turn, multiple immune cell subsets have profound consequences on promoting neovascularization. Vascular normalization, a promising anti-angiogenic strategy, can enhance vascular perfusion and promote the infiltration of immune effector cells into tumors via correcting aberrant tumor blood vessels, resulting in the potentiation of immunotherapy. More interestingly, immunotherapies are prone to boost the efficacy of various anti-angiogenic therapies and/or promote the morphological and functional alterations in tumor vasculature. Therefore, immune reprograming and vascular normalization appear to be reciprocally regulated. In this review, we mainly summarize how tumor vasculature propels an immunosuppressive phenotype and how innate and adaptive immune cells modulate angiogenesis during tumor progression. We further highlight recent advances of anti-angiogenic immunotherapies in preclinical and clinical settings to solidify the concept that targeting both tumor blood vessels and immune suppressive cells provides an efficacious approach for the treatment of cancer.