Ectopic lymphoid structures function as microniches for tumor progenitor cells in hepatocellular carcinoma. Nat Immunol. 2015;16:1235-1244. [PMID: 26502405 DOI: 10.1038/ni.3290]

Intra-tumoral tertiary lymphoid structures are associated with a low risk of early recurrence of hepatocellular carcinoma

BACKGROUND & AIMS

Tertiary lymphoid structures (TLSs) provide a local and critical microenvironment for generating anti-tumor cellular and humoral immune responses. TLSs are associated with improved clinical outcomes in most solid tumors investigated to date. However, their role in hepatocellular carcinoma (HCC) is debated, as they have recently been shown to promote the growth of malignant hepatocyte progenitors in the non-tumoral liver.

METHODS

We aimed to determine, by pathological review, the prognostic significance of both intra-tumoral and non-tumoral TLSs in a series of 273 patients with HCC treated by surgical resection in Henri Mondor University Hospital. Findings were further validated by gene expression profiling using a public data set (LCI cohort).

RESULTS

TLSs were identified in 47% of the tumors, by pathological review, with lymphoid aggregates, primary and secondary follicles in 26%, 16% and 5% of the cases, respectively. Univariate and multivariate analyses showed that intra-tumoral TLSs significantly correlated with a lower risk of early relapse (<2 years after surgery, hazard ratio 0.46, p = 0.005). Interestingly, the risk of recurrence was also related to the degree of TLS maturation (primary or secondary follicles vs. lymphoid aggregates, p = 0.01). A gene expression signature associated with the presence of intra-tumoral TLS was also independently associated with a lower risk of early relapse in the LCI cohort. No association between the density of TLSs located in the adjacent non-tumoral liver and early or late recurrence was observed.

CONCLUSIONS

We have shown that intra-tumoral TLSs are associated with a lower risk of early relapse in 2 independent cohorts of patients with HCC treated by surgical resection. Thus, intra-tumoral TLSs may reflect the existence of ongoing, effective anti-tumor immunity.

LAY SUMMARY

Tertiary lymphoid structures provide a critical microenvironment for generating anti-tumor immune responses, and are associated with improved clinical outcome in most cancers investigated. Their role in hepatocellular carcinoma is however debated. We show in the present study that intra-tumoral tertiary lymphoid structures are associated with a low risk of early relapse after surgical resection, suggesting that they reflect the existence of in situ, effective anti-tumor immunity.

Lect2 Controls Inflammatory Monocytes to Constrain the Growth and Progression of Hepatocellular Carcinoma

Leukocyte cell-derived chemotaxin-2 (LECT2) was originally identified as a hepatocyte-secreted chemokine-like factor and a positive target of β-catenin signaling. Here, we dissected out the mechanisms by which LECT2 modulates hepatocellular carcinoma (HCC) development using both HCC mouse models and human HCC samples. We have demonstrated that LECT2 exhibits dual abilities as it has profound repercussions on the tumor phenotype itself and the immune microenvironment. Its absence confers Ctnnb-1-mutated tumor hepatocytes a stronger ability to undergo epithelial to mesenchymal transition and fosters the accumulation of pejorative inflammatory monocytes harboring immunosuppressive properties and strong tumor-promoting potential. Consistent with our HCC mouse model, a low level of LECT2 in human HCC is strongly associated with high tumor grade and the presence of inflammatory infiltrates, emphasizing the clinical value of LECT2 in human liver tumorigenesis. Conclusion: Our findings have demonstrated that LECT2 is a key player in liver tumorigenesis because its absence reshapes the tumor microenvironment and the tumor phenotype, revealing LECT2 as a promising immunotherapeutic option for HCC.

A novel spontaneous hepatocellular carcinoma mouse model for studying T-cell exhaustion in the tumor microenvironment

Immunotherapy has ushered in a new era of cancer therapy, and this is also applicable to therapy of hepatocellular carcinoma (HCC). In this context, effective development of therapeutic strategies requires an HCC mouse model with known tumor-associated antigens (TAAs) and an HCC growth reporter. We created such a model using hydrodynamic injection and a transposon system to introduce AKT and NRAS and open reading frames (ORFs) encoding surrogate tumor antigens and luciferase into chromosomes of hepatocytes to induce nodular and diffuse tumors in the liver. TAA-specific CD8⁺ T cells were detected during HCC progression; however, these showed exhausted-like phenotypes and were unable to control tumor growth. Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAM) from the tumor microenvironment were found to contribute to the suppression of the CD8⁺ T-cell response. The transposon-based Akt/N-Ras-induced HCC mouse model we developed enables researchers to monitor tumor growth non-invasively and to quantify and characterize endogenous or adoptively transferred TAA-specific CD8⁺ T-cell responses. These features make it a suitable preclinical model for exploration and evaluation of immune checkpoint inhibitors and cell-based immunotherapies for HCC treatment.

microRNA 193a-5p Regulates Levels of Nucleolar- and Spindle-Associated Protein 1 to Suppress Hepatocarcinogenesis

BACKGROUND & AIMS

We performed an integrated analysis to identify microRNAs (miRNAs) and messenger RNAs (mRNAs) with altered expression in liver tumors from 3 mouse models of hepatocellular carcinoma (HCC) and human tumor tissues.

METHODS

We analyzed miRNA and mRNA expression profiles of liver tissues from mice with diethylnitrosamine-induced hepatocarcinogenesis, conditional expression of lymphotoxin alpha and lymphotoxin beta, or inducible expression of a Myc transgene (Tet-O-Myc mice), as well as male C57BL/6 mice (controls). miRNA mimics were expressed and miRNAs and mRNAs were knocked down in human (Huh7, Hep3B, JHH2) hepatoma cell lines; cells were analyzed for viability, proliferation, apoptosis, migration, and invasion. Cells were grown as xenograft tumors in nude mice and analyzed. We combined in silico target gene prediction with mRNA profiles from all 3 mouse models. We quantified miRNA levels in 146 fresh-frozen tissues from patients (125 HCCs, 17 matched nontumor tissues, and 4 liver samples from patients without cancer) and published human data sets and tested correlations with patient survival times using Kaplan-Meier curves and the log-rank test. Levels of NUSAP1 mRNA were quantified in 237 HCCs and 5 nontumor liver samples using the TaqMan assay.

RESULTS

Levels of the miRNA 193a-5p (MIR193A-5p) were reduced in liver tumors from all 3 mouse tumor models and in human HCC samples, compared with nontumor liver tissues. Expression of a MIR193A-5p mimic in hepatoma cells reduced proliferation, survival, migration, and invasion and their growth as xenograft tumors in nude mice. We found nucleolar and spindle-associated protein 1 (NUSAP1) to be a target of MIR193A-5p; HCC cells and tissues with low levels of MIR193A-5p had increased expression of NUSAP1. Increased levels of NUSAP1 in HCC samples correlated with shorter survival times of patients. Knockdown of NUSAP1 in Huh7 cells reduced proliferation, survival, migration, and growth as xenograft tumors in nude mice. Hydrodynamic tail-vein injections of a small hairpin RNA against NUSAP1 reduced growth of Akt1-Myc-induced tumors in mice.

CONCLUSIONS

MIR193A-5p appears to prevent liver tumorigenesis by reducing levels of NUSAP1. Levels of MIR193A-5p are reduced in mouse and human HCC cells and tissues, leading to increased levels of NUSAP1, associated with shorter survival times of patients. Integrated analyses of miRNAs and mRNAs in tumors from mouse models can lead to identification of therapeutic targets in humans. The currently reported miRNA and mRNA profiling data have been submitted to the Gene Expression Omnibus (super-series accession number GSE102418).

Obesity Drives STAT-1-Dependent NASH and STAT-3-Dependent HCC

Obesity is a major driver of cancer, especially hepatocellular carcinoma (HCC). The prevailing view is that non-alcoholic steatohepatitis (NASH) and fibrosis or cirrhosis are required for HCC in obesity. Here, we report that NASH and fibrosis and HCC in obesity can be dissociated. We show that the oxidative hepatic environment in obesity inactivates the STAT-1 and STAT-3 phosphatase T cell protein tyrosine phosphatase (TCPTP) and increases STAT-1 and STAT-3 signaling. TCPTP deletion in hepatocytes promoted T cell recruitment and ensuing NASH and fibrosis as well as HCC in obese C57BL/6 mice that normally do not develop NASH and fibrosis or HCC. Attenuating the enhanced STAT-1 signaling prevented T cell recruitment and NASH and fibrosis but did not prevent HCC. By contrast, correcting STAT-3 signaling prevented HCC without affecting NASH and fibrosis. TCPTP-deletion in hepatocytes also markedly accelerated HCC in mice treated with a chemical carcinogen that promotes HCC without NASH and fibrosis. Our studies reveal how obesity-associated hepatic oxidative stress can independently contribute to the pathogenesis of NASH, fibrosis, and HCC.

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Obesity promotes hepatic STAT-1 and STAT-3 signaling

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Obesity promotes STAT-1-dependent T cell-infiltration, NASH, and fibrosis

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Obesity promotes NASH-independent STAT-3-dependent HCC

The Multiple Layers of the Tumor Environment

The notion of tumor microenvironment (TME) has been brought to the forefront of recent scientific literature on cancer. However, there is no consensus on how to define and spatially delineate the TME. We propose that the time is ripe to go beyond an all-encompassing list of the components of the TME, and to construct a multilayered view of cancer. We distinguish six layers of environmental interactions with the tumor and show that they are associated with distinct mechanisms, and ultimately with distinct therapeutic approaches.

Targeting IKKβ in Cancer: Challenges and Opportunities for the Therapeutic Utilisation of IKKβ Inhibitors

Deregulated NF-κB signalling is implicated in the pathogenesis of numerous human inflammatory disorders and malignancies. Consequently, the NF-κB pathway has attracted attention as an attractive therapeutic target for drug discovery. As the primary, druggable mediator of canonical NF-κB signalling the IKKβ protein kinase has been the historical focus of drug development pipelines. Thousands of compounds with activity against IKKβ have been characterised, with many demonstrating promising efficacy in pre-clinical models of cancer and inflammatory disease. However, severe on-target toxicities and other safety concerns associated with systemic IKKβ inhibition have thus far prevented the clinical approval of any IKKβ inhibitors. This review will discuss the potential reasons for the lack of clinical success of IKKβ inhibitors to date, the challenges associated with their therapeutic use, realistic opportunities for their future utilisation, and the alternative strategies to inhibit NF-κB signalling that may overcome some of the limitations associated with IKKβ inhibition.

The Paradoxical Role of NKG2D in Cancer Immunity

The activating receptor NKG2D and its ligands are recognized as a potent immune axis that controls tumor growth and microbial infections. With regards to cancer surveillance, various studies have demonstrated the antitumor function mediated by NKG2D on natural killer cells and on conventional and unconventional T cells. The use of NKG2D-deficient mice established the importance of NKG2D in delaying tumor development in transgenic mouse models of cancer. However, we recently demonstrated an unexpected, flip side to this coin, the ability for NKG2D to contribute to tumor growth in a model of inflammation-driven liver cancer. With a focus on the liver, here, we review current knowledge of NKG2D-mediated tumor surveillance and discuss evidence supporting a dual role for NKG2D in cancer immunity. We postulate that in certain advanced cancers, expression of ligands for NKG2D can drive cancer progression rather than rejection. We propose that the nature of the microenvironment within and surrounding tumors impacts the outcome of NKG2D activation. In a form of autoimmune attack, NKG2D promotes tissue damage, mostly in the inflamed tissue adjacent to the tumor, facilitating tumor progression while being ineffective at rejecting transformed cells in the tumor bed.

Immune checkpoint blockade for the treatment of human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers with a high recurrence rate. Currently, tyrosine kinase inhibitors (TKIs) are the first-line treatment for cases refractory to conventional therapies. However, the acquisition of somatic mutations can result in TKI resistance. Clinical evidence suggests that acquired immunity contributes to the suppression of tumor recurrence, indicating the potential of induced antitumor immune reaction for the treatment of HCC. Recently, immune checkpoint inhibitors have become available for the treatment of malignancies. They are effective regardless of the response to prior therapies and a durable effect can be expected, which should be attributed to an adaptive immunity to HCC components. The results of phase I/II trials of nivolumab, an anti-programmed cell death-1 antibody, showed that 20% of patients showed objective response and that nivolumab was effective regardless of prior sorafenib treatment and viral status. Nivolumab received expedited Food and Drug Administration approval in 2017 for the treatment of advanced HCC after failure or intolerance to sorafenib. However, the majority of the patients remain refractory, likely due to the solid immune suppressive status, which involves many stromal cells, humoral mediators, and suppressive checkpoint molecules. Therefore, current clinical trials are focusing on how immunosuppressive conditions in HCC might be overcome using immune checkpoint inhibitors in combination with different types of immune checkpoint blockades, TKIs, and other conventional treatments. The development of immune checkpoint inhibitors is rapidly progressing and these inhibitors are likely to be key agents for HCC treatment in the near feature.

Hyperactive gp130/STAT3-driven gastric tumourigenesis promotes submucosal tertiary lymphoid structure development

Tertiary lymphoid structures (TLSs) display phenotypic and functional characteristics of secondary lymphoid organs, and often develop in tissues affected by chronic inflammation, as well as in certain inflammation-associated cancers where they are prognostic of improved patient survival. However, the mechanisms that govern the development of tumour-associated TLSs remain ill-defined. Here, we observed tumour-associated TLSs in a preclinical mouse model (gp130F/F ) of gastric cancer, where tumourigenesis is dependent on hyperactive STAT3 signalling through the common IL-6 family signalling receptor, gp130. Gastric tumourigenesis was associated with the development of B and T cell-rich submucosal lymphoid aggregates, containing CD21+ cellular networks and high endothelial venules. Temporally, TLS formation coincided with the development of gastric adenomas and induction of homeostatic chemokines including Cxcl13, Ccl19 and Ccl21. Reflecting the requirement of gp130-driven STAT3 signalling for gastric tumourigenesis, submucosal TLS development was also STAT3-dependent, but independent of the cytokine IL-17 which has been linked with lymphoid neogenesis in chronic inflammation and autoimmunity. Interestingly, upregulated lymphoid chemokine expression and TLS formation were also observed in a chronic gastritis model induced by Helicobacter felis infection. Tumour-associated TLSs were also observed in patients with intestinal-type gastric cancer, and a gene signature linked with TLS development in gp130F/F mice was associated with advanced clinical disease, but was not prognostic of patient survival. Collectively, our in vivo data reveal that hyperactive gp130-STAT3 signalling closely links gastric tumourigenesis with lymphoid neogenesis, and while a TLS gene signature was associated with advanced gastric cancer in patients, it did not indicate a favourable prognosis.

The hyaluronic acid-rich node and duct system is a structure organized for innate immunity and mediates the local inflammation

The Hyaluronic Acid-rich Node and Duct System (HAR-NDS or NDS), Primo Vascular System (PVS) or Bonghan System (BHS), is thought to be a third circulatory system independent of the blood and lymphatic systems and a structure of connected nodes and ducts. Although it seems to be part of the immune system as it is enriched with cells of innate immunity, little is known about its immunological roles. We performed cellular profiling and secretome analysis of NDS in a steady state and under TLR2- or TLR4-mediated local inflammation, and found that the NDS is pre-dominantly enriched with the myeloid cells, selectively attracts the inflammatory macrophages and neutrophils, has a flexible structure just like the lymph node, and is structured with the fibroblastic reticular cells and reticular network. NDS dominantly harbored the myeloid cells in both steady and activated status, and secreted various types of inflammatory cytokines by proinflammatory stimuli. These results suggest that NDS is the lymphoid structure for the innate immunity and plays an intermediary role in the innate immune cell-mediated local inflammation.

Synergistic and low adverse effect cancer immunotherapy by immunogenic chemotherapy and locally expressed PD-L1 trap

Although great success has been obtained in the clinic, the current immune checkpoint inhibitors still face two challenging problems: low response rate and immune-related adverse effects (irAEs). Here we report the combination of immunogenic chemotherapy and locally expressed PD-L1 trap fusion protein for efficacious and safe cancer immunotherapy. We demonstrate that oxaliplatin (OxP) boosts anti-PD-L1 mAb therapy against murine colorectal cancer. By design of a PD-L1 trap and loading its coding plasmid DNA into a lipid-protamine-DNA nanoparticle, PD-L1 trap is produced transiently and locally in the tumor microenvironment, and synergizes with OxP for tumor inhibition. Significantly, unlike the combination of OxP and anti-PD-L1 mAb, the combination of OxP and PD-L1 trap does not induce obvious Th17 cells accumulation in the spleen, indicating better tolerance and lower tendency to irAEs. The reports here may highlight the potential of applying PD-L1 inhibitor, especially locally expressed PD-L1 trap, in cancer therapy following OxP-based chemotherapy.

Microsatellite-stable (MSS) colorectal cancer (CRC) has shown poor response to checkpoint blockade immunotherapy. Here, the authors show that the combination of oxaliplatin with anti-PDL1 mAb is specifically efficient in the treatment of MSS CRC.

Understanding the tumor immune microenvironment (TIME) for effective therapy

The clinical successes in immunotherapy have been both astounding and at the same time unsatisfactory. Countless patients with varied tumor types have seen pronounced clinical response with immunotherapeutic intervention; however, many more patients have experienced minimal or no clinical benefit when provided the same treatment. As technology has advanced, so has the understanding of the complexity and diversity of the immune context of the tumor microenvironment and its influence on response to therapy. It has been possible to identify different subclasses of immune environment that have an influence on tumor initiation and response and therapy; by parsing the unique classes and subclasses of tumor immune microenvironment (TIME) that exist within a patient's tumor, the ability to predict and guide immunotherapeutic responsiveness will improve, and new therapeutic targets will be revealed.

Immune-based identification of cancer patients at high risk of progression

Tumors are highly heterogeneous structures where malignant cells interact with a large variety of cell populations, including a clinically-relevant immune component. We review and compare the most recent methods designed to analyze and quantify the composition of immune and stromal microenvironment of tumors and discuss their use in identification of patients for high risk of progression. If the impact of the various immune components on patient's relapse share common rules in most malignancies, clear cell renal cell tumors behave differently with regards to immunity. We focus on this specific pathology to show how the tumor interacts with the host's immune system and how this intricate relationship shapes the clinical outcome.

GADD45β Loss Ablates Innate Immunosuppression in Cancer

T-cell exclusion from the tumor microenvironment (TME) is a major barrier to overcoming immune escape. Here, we identify a myeloid-intrinsic mechanism governed by the NF-κB effector molecule GADD45β that restricts tumor-associated inflammation and T-cell trafficking into tumors. In various models of solid cancers refractory to immunotherapies, including hepatocellular carcinoma and ovarian adenocarcinoma, Gadd45b inhibition in myeloid cells restored activation of proinflammatory tumor-associated macrophages (TAM) and intratumoral immune infiltration, thereby diminishing oncogenesis. Our results provide a basis to interpret clinical evidence that elevated expression of GADD45B confers poor clinical outcomes in most human cancers. Furthermore, they suggest a therapeutic target in GADD45β for reprogramming TAM to overcome immunosuppression and T-cell exclusion from the TME.Significance: These findings define a myeloid-based immune checkpoint that restricts T-cell trafficking into tumors, with potentially important therapeutic implications to generally improve the efficacy of cancer immunotherapy. Cancer Res; 78(5); 1275-92. ©2017 AACR.

Role of nonresolving inflammation in hepatocellular carcinoma development and progression

Hepatocellular carcinoma (HCC) has become a leading cause of cancer-related death, making the elucidation of its underlying mechanisms an urgent priority. Inflammation is an adaptive response to infection and tissue injury under strict regulations. When the host regulatory machine runs out of control, nonresolving inflammation occurs. Nonresolving inflammation is a recognized hallmark of cancer that substantially contributes to the development and progression of HCC. The HCC-associated inflammation can be initiated and propagated by extrinsic pathways through activation of pattern-recognition receptors (PRRs) by pathogen-associated molecule patterns (PAMPs) derived from gut microflora or damage-associated molecule patterns (DAMPs) released from dying liver cells. The inflammation can also be orchestrated by the tumor itself through secreting factors that recruit inflammatory cells to the tumor favoring the buildup of a microenvironment. Accumulating datas from human and mouse models showed that inflammation promotes HCC development by promoting proliferative and survival signaling, inducing angiogenesis, evading immune surveillance, supporting cancer stem cells, activating invasion and metastasis as well as inducing genomic instability. Targeting inflammation may represent a promising avenue for the HCC treatment. Some inhibitors targeting inflammatory pathways have been developed and under different stages of clinical trials, and one (sorafenib) have been approved by FDA. However, as most of the data were obtained from animal models, and there is a big difference between human HCC and mouse HCC models, it is challenging on successful translation from bench to bedside.

Growth and Immune Evasion of Lymph Node Metastasis

Cancer patients with lymph node (LN) metastases have a worse prognosis than those without nodal disease. However, why LN metastases correlate with reduced patient survival is poorly understood. Recent findings provide insight into mechanisms underlying tumor growth in LNs. Tumor cells and their secreted molecules engage stromal, myeloid, and lymphoid cells within primary tumors and in the lymphatic system, decreasing antitumor immunity and promoting tumor growth. Understanding the mechanisms of cancer survival and growth in LNs is key to designing effective therapy for the eradication of LN metastases. In addition, uncovering the implications of LN metastasis for systemic tumor burden will inform treatment decisions. In this review, we discuss the current knowledge of the seeding, growth, and further dissemination of LN metastases.

The immunology of hepatocellular carcinoma

In contrast to most other malignancies, hepatocellular carcinoma (HCC), which accounts for approximately 90% of primary liver cancers, arises almost exclusively in the setting of chronic inflammation. Irrespective of etiology, a typical sequence of chronic necroinflammation, compensatory liver regeneration, induction of liver fibrosis and subsequent cirrhosis often precedes hepatocarcinogenesis. The liver is a central immunomodulator that ensures organ and systemic protection while maintaining immunotolerance. Deregulation of this tightly controlled liver immunological network is a hallmark of chronic liver disease and HCC. Notably, immunotherapies have raised hope for the successful treatment of advanced HCC. Here we summarize the roles of specific immune cell subsets in chronic liver disease, with a focus on non-alcoholic steatohepatitis and HCC. We review new advances in immunotherapeutic approaches for the treatment of HCC and discuss the challenges posed by the immunotolerant hepatic environment and the dual roles of adaptive and innate immune cells in HCC.

Immune Cell Infiltration and Tertiary Lymphoid Structures as Determinants of Antitumor Immunity

Limited representation of intratumoral immune cells is a major barrier to tumor control. However, simply enhancing immune responses in tumor-draining lymph nodes or through adoptive transfer may not overcome the limited ability of tumor vasculature to support effector infiltration. An alternative is to promote a sustained immune response intratumorally. This idea has gained traction with the observation that many tumors are associated with tertiary lymphoid structures (TLS), which organizationally resemble lymph nodes. These peri- and intratumoral structures are usually, but not always, associated with positive prognoses in patients. Preclinical and clinical data support a role for TLS in modulating immunity in the tumor microenvironment. However, there appear to be varied functions of TLS, potentially based on their structure or location in relation to the tumor or the origin or location of the tumor itself. Understanding more about TLS development, composition, and function may offer new therapeutic opportunities to modulate antitumor immunity.

Defining High Endothelial Venules and Tertiary Lymphoid Structures in Cancer

High endothelial venules (HEVs) are structurally distinct blood vessels that develop during embryonic and neonatal life in all secondary lymphoid organs except the spleen. HEVs are critical for initiating and maintaining immune responses because they extract naïve and memory lymphocytes from the bloodstream, regardless of antigen receptor specificity, and deliver them to antigen-presenting cells inside lymph nodes under homeostatic conditions. HEVs also develop postnatally in nonlymphoid organs during chronic inflammation driven by autoimmunity, infection, allografts, and cancer. Extranodal HEVs are usually surrounded by dense lymphocytic infiltrates organized into lymph-node like, T- and B-cell-rich areas called tertiary lymphoid structures (TLS). HEV neogenesis is thought to facilitate the generation of tissue-destroying lymphocytes inside chronically inflamed tissues and cancers.We are studying the mechanisms underpinning HEV neogenesis in solid cancers and the role of homeostatic T-cell trafficking in controlling cancer immunity. In this chapter we describe methods for identifying HEV in tissue sections of cancerous tissues in humans and mice using immunohistochemical staining for the HEV-specific marker peripheral lymph node addressin (PNAd). L-selectin binding to PNAd is a necessary first step in homeostatic lymphocyte trafficking which is the defining function of HEV. We also describe methods to measure L-selectin-dependent homing of lymphocytes from the bloodstream into lymphoid tissues and tumors in preclinical cancer models.

Exploring the Role of Tertiary Lymphoid Structures Using a Mouse Model of Bacteria-Infected Lungs

Animal models can be helpful tools for deciphering the generation, maintenance, and role of tertiary lymphoid structures (TLS) during infections or tumor development. We describe here the establishment of a persistent lung infection in immune-competent mice by intratracheal instillation of agarose beads containing Pseudomonas aeruginosa or Staphylococcus aureus bacteria. After instillation, animals develop a chronic pulmonary infection, marked by the presence of TLS. This experimental setting allows the study of the function of TLS induced by bacteria encountered in patients with cystic fibrosis (CF) as P. aeruginosa and S. aureus are the two main bacterial strains that infect bronchi of adult CF patients. Additionally, we describe also how to manipulate the immune response in these infected animals by targeting immune cells involved in TLS function. Overall, this approach makes it possible to explore the role of chronic inflammation in the induction and maintenance of TLS in infected tissues.

Tertiary Lymphoid Structures in Cancer: Drivers of Antitumor Immunity, Immunosuppression, or Bystander Sentinels in Disease?

Secondary lymphoid organs are integral to initiation and execution of adaptive immune responses. These organs provide a setting for interactions between antigen-specific lymphocytes and antigen-presenting cells recruited from local infected or inflamed tissues. Secondary lymphoid organs develop as a part of a genetically preprogrammed process during embryogenesis. However, organogenesis of secondary lymphoid tissues can also be recapitulated in adulthood during de novo lymphoid neogenesis of tertiary lymphoid structures (TLSs). These ectopic lymphoid-like structures form in the inflamed tissues afflicted by various pathological conditions, including cancer, autoimmunity, infection, or allograft rejection. Studies are beginning to shed light on the function of such structures in different disease settings, raising important questions regarding their contribution to progression or resolution of disease. Data show an association between the tumor-associated TLSs and a favorable prognosis in various types of human cancer, attracting the speculation that TLSs support effective local antitumor immune responses. However, definitive evidence for the role for TLSs in fostering immune responses in vivo are lacking, with current data remaining largely correlative by nature. In fact, some more recent studies have even demonstrated an immunosuppressive, tumor-promoting role for cancer-associated TLSs. In this review, we will discuss what is known about the development of cancer-associated TLSs and the current understanding of their potential role in the antitumor immune response.

Viral Load Affects the Immune Response to HBV in Mice With Humanized Immune System and Liver

BACKGROUND & AIMS

Hepatitis B virus (HBV) infects hepatocytes, but the mechanisms of the immune response against the virus and how it affects disease progression are unclear.

METHODS

We performed studies with BALB/c Rag2^-/-Il2rg^-/-Sirpa^NODAlb-uPA^tg/tg mice, stably engrafted with human hepatocytes (HUHEP) with or without a human immune system (HIS). HUHEP and HIS-HUHEP mice were given an intraperitoneal injection of HBV. Mononuclear cells were isolated from spleen and liver for analysis by flow cytometry. Liver was analyzed by immunohistochemistry and mRNA levels were measured by quantitative reverse transcription polymerase chain reaction (PCR). Plasma levels of HBV DNA were quantified by PCR reaction, and antigen-specific antibodies were detected by immunocytochemistry of HBV-transfected BHK-21 cells.

RESULTS

Following HBV infection, a complete viral life cycle, with production of HBV DNA, hepatitis B e (HBe), core (HBc) and surface (HBs) antigens, and covalently closed circular DNA, was observed in HUHEP and HIS-HUHEP mice. HBV replicated unrestricted in HUHEP mice resulting in high viral titers without pathologic effects. In contrast, HBV-infected HIS-HUHEP mice developed chronic hepatitis with 10-fold lower titers and antigen-specific IgGs, (anti-HBs, anti-HBc), consistent with partial immune control. HBV-infected HIS-HUHEP livers contained infiltrating Kupffer cells, mature activated natural killer cells (CD69+), and PD-1+ effector memory T cells (CD45RO+). Reducing the viral inoculum resulted in more efficient immune control. Plasma from HBV-infected HIS-HUHEP mice had increased levels of inflammatory and immune-suppressive cytokines (C-X-C motif chemokine ligand 10 and interleukin 10), which correlated with populations of intrahepatic CD4+ T cells (CD45RO+PD-1+). Mice with high levels of viremia had HBV-infected liver progenitor cells. Giving the mice the nucleoside analogue entecavir reduced viral loads and decreased liver inflammation.

CONCLUSION

In HIS-HUHEP mice, HBV infection completes a full life cycle and recapitulates some of the immunopathology observed in patients with chronic infection. Inoculation with different viral loads led to different immune responses and levels of virus control. We found HBV to infect liver progenitor cells, which could be involved in hepatocellular carcinogenesis. This is an important new system to study anti-HBV immune responses and screen for combination therapies against hepatotropic viruses.

Systematic Screening of Chemokines to Identify Candidates to Model and Create Ectopic Lymph Node Structures for Cancer Immunotherapy

The induction of ectopic lymph node structures (ELNs) holds great promise to augment immunotherapy against multiple cancers including metastatic melanoma, in which ELN formation has been associated with a unique immune-related gene expression signature composed of distinct chemokines. To investigate the therapeutic potential of ELNs induction, preclinical models of ELNs are needed for interrogation of these chemokines. Computational models provide a non-invasive, cost-effective method to investigate leukocyte trafficking in the tumor microenvironment, but parameterizing such models is difficult due to differing assay conditions and contexts among the literature. To better achieve this, we systematically performed microchemotaxis assays on purified immune subsets including human pan-T cells, CD4⁺ T cells, CD8⁺ T cells, B cells, and NK cells, with 49 recombinant chemokines using a singular technique, and standardized conditions resulting in a dataset representing 238 assays. We then outline a groundwork computational model that can simulate cellular migration in the tumor microenvironment in response to a chemoattractant gradient created from stromal, lymphoid, or antigen presenting cell interactions. The resulting model can then be parameterized with standardized data, such as the dataset presented here, and demonstrates how a computational approach can help elucidate developing ELNs and their impact on tumor progression.

Treg Depletion Licenses T Cell-Driven HEV Neogenesis and Promotes Tumor Destruction

T-cell infiltration into tumors represents a critical bottleneck for immune-mediated control of cancer. We previously showed that this bottleneck can be overcome by depleting immunosuppressive Foxp3+ regulatory T cells (Tregs), a process that can increase frequencies of tumor-infiltrating lymphocytes through promoting the development of specialized portals for lymphocyte entry, namely high endothelial venules (HEVs). In this paper, we used a carcinogen-induced tumor model that allows for coevolution of the tumor microenvironment and the immune response to demonstrate that Treg depletion not only results in widespread disruption to HEV networks in lymph nodes (LNs) but also activates CD8+ T cells, which then drive intratumoral HEV development. Formation of these vessels contrasts with ontogenic HEV development in LNs in that the process is dependent on the TNF receptor and independent of lymphotoxin β receptor-mediated signaling. These intratumoral HEVs do not express the chemokine CCL21, revealing a previously undescribed intratumoral blood vessel phenotype. We propose a model where Treg depletion enables a self-amplifying loop of T-cell activation, which promotes HEV development, T-cell infiltration, and ultimately, tumor destruction. The findings point to a need to test for HEV development as part of ongoing clinical studies in patients with cancer. Cancer Immunol Res; 5(11); 1005-15. ©2017 AACR.

Tertiary Lymphoid Structures Associate with Tumour Stage in Urothelial Bladder Cancer

BACKGROUND

Urothelial bladder cancer (UBC) is a highly prevalent disease in North America, however its optimal management remains elusive. The contribution of B cell associated responses is poorly understood in bladder cancer. Lymphoid neogenesis is a hallmark of an active immune response at tumor sites that sometimes leads to formation of tertiary lymphoid structures (TLS) that resemble germinal centers formed in secondary lymphoid organs.

OBJECTIVE

This study was conducted with an aim to investigate the presence and characteristics of TLS in UBC with a focus to compare and contrast the TLS formation in treatment naive low grade non-muscle invasive (NMIBC) and muscle invasive bladder cancers (MIBC).

METHODS

The study cohort consisted of transurethral bladder resection tumour (TURBT) specimens from 28 patients. Sections showing lymphoid aggregates in hematoxylin and eosin (H&E) stained TURBT specimens were further subjected to multi-color immunohistochemistry using immune cell markers specific to CD20+ B cells, CD3+ and CD8+ T cells, PNAd+ high endothelial venules, CD208+ mature dendritic cells, CD21+ follicular dendritic cells to confirm the hallmarks of classical germinal centers.

RESULTS

Our pilot study investigating the presence of TLS in bladder cancer patients is the first to demonstrate that well-formed TLS are more common in aggressive high grade MIBC tumors compared to low grade NIMBC.

CONCLUSIONS

These novel findings suggest B cell mediated anti-tumour humoral immune responses in bladder cancer progression.

Resident fibroblasts in the kidney: a major driver of fibrosis and inflammation

Background

Chronic kidney disease (CKD) is a leading cause of end stage renal disease (ESRD) and cardiovascular morbidity and mortality worldwide, resulting in a growing social and economic burden. The prevalence and burden of CKD is anticipated to further increase over the next decades as a result of aging.

Main body of abstract

In the pathogenesis of CKD, irrespective of the etiology, resident fibroblasts are key players and have been demonstrated to play crucial roles for disease initiation and progression. In response to injury, resident fibroblasts transdifferentiate into myofibroblasts that express alpha smooth muscle actin (αSMA) and have an increased capacity to produce large amounts of extracellular matrix (ECM) proteins, leading to renal fibrosis. In addition to this fundamental role of fibroblasts as drivers for renal fibrosis, growing amounts of evidence have shown that resident fibroblasts are also actively involved in initiating and promoting inflammation during kidney injury. During the myofibroblastic transition described above, resident fibroblasts activate NF-κB signaling and produce pro-inflammatory cytokines and chemokines, promoting inflammation. Furthermore, under aging milieu, resident fibroblasts transdifferentiate into several distinct phenotypic fibroblasts, including CXCL13/CCL19-producing fibroblasts, retinoic acid-producing fibroblasts, and follicular dendritic cells, in response to injury and orchestrate tertiary lymphoid tissue (TLT) formation, which results in uncontrolled aberrant inflammation and retards tissue repair. Anti-inflammatory agents can improve myofibroblastic transdifferentiation and abolish TLT formation, suggesting that targeting these inflammatory fibroblasts can potentially ameliorate kidney disease.

Short conclusion

Beyond its conventional role as an executor of fibrosis, resident fibroblasts display more pro-inflammatory phenotypes and contribute actively to driving inflammation during kidney injury.

The immune contexture in cancer prognosis and treatment

Immunotherapy is currently the most rapidly advancing area of clinical oncology, and provides the unprecedented opportunity to effectively treat, and even cure, several previously untreatable malignancies. A growing awareness exists of the fact that the success of chemotherapy and radiotherapy, in which the patient's disease can be stabilized well beyond discontinuation of treatment (and occasionally is cured), also relies on the induction of a durable anticancer immune response. Indeed, the local immune infiltrate undergoes dynamic changes that accompany a shift from a pre-existing immune response to a therapy-induced immune response. As a result, the immune contexture, which is determined by the density, composition, functional state and organization of the leukocyte infiltrate of the tumour, can yield information that is relevant to prognosis, prediction of a treatment response and various other pharmacodynamic parameters. Several complementary technologies can be used to explore the immune contexture of tumours, and to derive biomarkers that could enable the adaptation of individual treatment approaches for each patient, as well as monitoring a response to anticancer therapies.

Tertiary Lymphoid Structures: An Anti-tumor School for Adaptive Immune Cells and an Antibody Factory to Fight Cancer?

Tertiary lymphoid structures (TLS) present in human solid tumors are essential for the shaping of a favorable immune micro-environment to control tumor development in most cases. They represent a formidable school for T-cell priming, B cell activation, and differentiation into plasma cells and an exquisitely located factory for antibody production. The manipulation of TLS neogenesis and maintenance represents, therefore, an exciting task to set up efficient anti-cancer vaccine strategies leading to long-lasting anti-tumor adaptive responses. To achieve this goal, a number of important issues are still pending. How TLS-T and -B cells and antibodies locally produced are related to the improved survival of cancer patients with high density of TLS is still unclear. In addition, the mechanisms by which tumors escape the immune surveillance exerted by TLS are still poorly understood and the role of immune suppressive cytokines, regulatory T cells, and/or antibodies in this process remains to be explored. The identification of the key parameters that distinguish TLS with anti- or possible pro-tumor activity is also essential to make the therapeutic targeting of TLS a success. Finally, how TLS-based therapeutic approaches can be associated with targeted therapies or immunointerventions, such as the use of ICP blockers to improve anti-tumor responses, is an open question. We will discuss these different issues in the present review.

Liver specific gene immunotherapies resolve immune suppressive ectopic lymphoid structures of liver metastases and prolong survival

The ability to generate potent immunotherapies locally and transiently for the treatment of cancers is a promising strategy to improve efficacy and decrease off-target toxicities. Here, we explored an alternative approach for the delivery of immunotherapeutic agents, in which we deliver the pDNA of an engineered PD-L1 trap and/or CXCL12 trap to the nucleus of liver hepatocytes via a lipid calcium phosphate nanoparticle. This strategy greatly increased the concentrations of immunotherapeutic agents in the local tissue, allowing the therapy to inhibit the accumulation of immune suppressive cells and liver metastasis. Furthermore, we find that the lipid calcium phosphate nanoparticles containing the pCXCL12 trap resolved the formation of immune suppressive ectopic lymphoid structures, while the pPD-L1 trap promoted T-cell survival and migration into the liver following vaccination against tumor antigens (>180% increase in survival). This approach showed superior efficacy in the treatment of the liver metastasis compared to free protein immunotherapies. This strategy should be considered as an approach to support liver metastasis therapies as well as for future research interested in manipulating the chemokine/cytokine immune factors within the liver.

SIGNIFICANCE

Our approach results in transient liver specific expression of gene immunotherapies with improved efficacy and reduced off-target toxicities over traditional systemically administered immunotherapies. This approach would allow clinicians to manipulate the liver and immune microenvironment to resist cancer invasion, improve organ health, and prolong patient survival.

IGFBP7 Deletion Promotes Hepatocellular Carcinoma

Activation of IGF signaling is a major oncogenic event in diverse cancers, including hepatocellular carcinoma (HCC). In this setting, the insulin-like growth factor binding protein IGFBP7 inhibits IGF signaling by binding the IGF1 receptor (IGF1R), functioning as a candidate tumor suppressor. IGFBP7 abrogates tumors by inhibiting angiogenesis and inducing cancer-specific senescence and apoptosis. Here, we report that Igfbp7-deficient mice exhibit constitutively active IGF signaling, presenting with proinflammatory and immunosuppressive microenvironments and spontaneous liver and lung tumors occurring with increased incidence in carcinogen-treated subjects. Igfbp7 deletion increased proliferation and decreased senescence of hepatocytes and mouse embryonic fibroblasts, effects that were blocked by treatment with IGF1 receptor inhibitor. Significant inhibition of genes regulating immune surveillance was observed in Igfbp7^-/- murine livers, which was associated with a marked inhibition in antigen cross-presentation by Igfbp7^-/- dendritic cells. Conversely, IGFBP7 overexpression inhibited growth of HCC cells in syngeneic immunocompetent mice. Depletion of CD4⁺ or CD8⁺ T lymphocytes abolished this growth inhibition, identifying it as an immune-mediated response. Our findings define an immune component of the pleiotropic mechanisms through which IGFBP7 suppresses HCC. Furthermore, they offer a genetically based preclinical proof of concept for IGFBP7 as a therapeutic target for immune management of HCC. Cancer Res; 77(15); 4014-25. ©2017 AACR.

AllergoOncology - the impact of allergy in oncology: EAACI position paper

Th2 immunity and allergic immune surveillance play critical roles in host responses to pathogens, parasites and allergens. Numerous studies have reported significant links between Th2 responses and cancer, including insights into the functions of IgE antibodies and associated effector cells in both antitumour immune surveillance and therapy. The interdisciplinary field of AllergoOncology was given Task Force status by the European Academy of Allergy and Clinical Immunology in 2014. Affiliated expert groups focus on the interface between allergic responses and cancer, applied to immune surveillance, immunomodulation and the functions of IgE-mediated immune responses against cancer, to derive novel insights into more effective treatments. Coincident with rapid expansion in clinical application of cancer immunotherapies, here we review the current state-of-the-art and future translational opportunities, as well as challenges in this relatively new field. Recent developments include improved understanding of Th2 antibodies, intratumoral innate allergy effector cells and mediators, IgE-mediated tumour antigen cross-presentation by dendritic cells, as well as immunotherapeutic strategies such as vaccines and recombinant antibodies, and finally, the management of allergy in daily clinical oncology. Shedding light on the crosstalk between allergic response and cancer is paving the way for new avenues of treatment.

CD8 T cells contribute to lacrimal gland pathology in the nonobese diabetic mouse model of Sjögren syndrome

Sjögren syndrome is an autoimmune disease characterized by targeted destruction of the lacrimal and salivary glands resulting in symptoms of severe ocular and oral dryness. Despite its prevalence, the mechanisms driving autoimmune manifestations are unclear. In patients and in the nonobese diabetic (NOD) mouse model of Sjögren syndrome, lymphocytic infiltrates consist of CD4 and CD8 T cells, although the role of CD8 T cells in disease pathogenesis has been largely unexplored. Here, we evaluated the contribution of CD8 T cells to lacrimal and salivary gland autoimmunity. Within the lacrimal and salivary glands of NOD mice, CD8 T cells were proliferating, expressed an activated phenotype, and produced inflammatory cytokines. Transfer of purified CD8 T cells isolated from the cervical lymph nodes (LNs) of NOD mice into NOD-severe combined immunodeficiency recipients resulted in inflammation of the lacrimal glands, but was not sufficient to cause inflammation of the salivary glands. Lacrimal gland-infiltrating CD8 T cells displayed a cytotoxic phenotype, and epithelial cell damage in the lacrimal glands was observed in recipients of CD8 T cells regardless of the presence of CD4 T cells. Collectively, our results demonstrate that CD8 T cells have a pathogenic role in lacrimal gland autoimmunity. The gland-specific pathogenicity of CD8 T cells makes them a valuable resource to further understand the mechanisms that discriminate lacrimal versus salivary gland autoimmunity and for the development of new therapeutics that target the early stages of disease.

CCR6+ B lymphocytes responding to tumor cell-derived CCL20 support hepatocellular carcinoma progression via enhancing angiogenesis

BACKGROUND & AIMS

Different immune cells in tumor microenvironment shape tumor progression. CCL20 over-expression was reported as one of the "stemness" trait in TP53 mutated hepatocellular carcinoma (HCC). We aimed to understand the effect of CCL20 on HCC progression.

METHODS

In two HCC cohort patients (n=95, n=85 respectively), serum CCL20 concentration was quantified by using ELISA. Expressions of CCL20 and CCR6 in 41 paired HCC tumor and adjacent non-tumor tissues were determined by quantitative Real-Time PCR, confirmed by immunohistochemistry (CCL20) or by flow cytometry analysis (CCR6). Chemotaxis of splenocytes or purified CD19⁺ B cells to tumor cell-derived CCL20, and angiogenesis of different CD19⁺ B subtypes responding to tumor cell-derived CCL20 were measured in vitro. H22 murine hepatoma cells were inoculated into immunocompetent or immunodeficient SCID mice, tumor growth and metastasis were monitored after the mice were treated with anti-CCL20 neutralizing antibody or depleted B cells by anti-CD20.

RESULTS

Elevation of pretherapy serum CCL20 in HCC patients and increase of CCR6 expression in HCC tissues were closely associated with tumor metastasis and disease poor prognosis. In HCC tissues, CCL20 expression was positively correlated with CCR6 (R² =0.3134, P=0.0002), and CCR6 was exclusively identified in tumor infiltrated immune cells. CD19⁺CD5⁺ B lymphocytes expressed higher CCR6, responded to tumor cell-derived CCL20 and enhanced angiogenesis in vitro. Neutralizing CCL20 activity in immunocompetent mice, not in SCID mice, attenuated tumor incidence, restrained tumor growth and distal metastasis. Tumor angiogenesis was significantly inhibited after CCL20 activity was blockade. In addition, inhibiting B lymphocyte infiltration into tumor mileum also attenuated tumor growth.

CONCLUSIONS

Tumor cell-derived CCL20 interacts with CCR6 highly expressed CD19⁺CD5⁺ B cells, to promote HCC progression, which might be via enhancing angiogenesis.

Liver Cancer Cell of Origin, Molecular Class, and Effects on Patient Prognosis

Primary liver cancer is the second leading cause of cancer-related death worldwide and therefore a major public health challenge. We review hypotheses of the cell of origin of liver tumorigenesis and clarify the classes of liver cancer based on molecular features and how they affect patient prognosis. Primary liver cancer comprises hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), and other rare tumors, notably fibrolamellar carcinoma and hepatoblastoma. The molecular and clinical features of HCC versus iCCA are distinct, but these conditions have overlapping risk factors and pathways of oncogenesis. A better understanding of the cell types originating liver cancer can aid in exploring molecular mechanisms of carcinogenesis and therapeutic options. Molecular studies have identified adult hepatocytes as the cell of origin. These cells have been proposed to transform directly into HCC cells (via a sequence of genetic alterations), to dedifferentiate into hepatocyte precursor cells (which then become HCC cells that express progenitor cell markers), or to transdifferentiate into biliary-like cells (which give rise to iCCA). Alternatively, progenitor cells also give rise to HCCs and iCCAs with markers of progenitor cells. Advances in genome profiling and next-generation sequencing have led to the classification of HCCs based on molecular features and assigned them to categories such as proliferation-progenitor, proliferation-transforming growth factor β, and Wnt-catenin β1. iCCAs have been assigned to categories of proliferation and inflammation. Overall, proliferation subclasses are associated with a more aggressive phenotype and poor outcome of patients, although more specific signatures have refined our prognostic abilities. Analyses of genetic alterations have identified those that might be targeted therapeutically, such as fusions in the FGFR2 gene and mutations in genes encoding isocitrate dehydrogenases (in approximately 60% of iCCAs) or amplifications at 11q13 and 6p21 (in approximately 15% of HCCs). Further studies of these alterations are needed before they can be used as biomarkers in clinical decision making.

High Endothelial Venules and Other Blood Vessels: Critical Regulators of Lymphoid Organ Development and Function

The blood vasculature regulates both the development and function of secondary lymphoid organs by providing a portal for entry of hemopoietic cells. During the development of lymphoid organs in the embryo, blood vessels deliver lymphoid tissue inducer cells that initiate and sustain the development of lymphoid tissues. In adults, the blood vessels are structurally distinct from those in other organs due to the requirement for high levels of lymphocyte recruitment under non-inflammatory conditions. In lymph nodes (LNs) and Peyer's patches, high endothelial venules (HEVs) especially adapted for lymphocyte trafficking form a spatially organized network of blood vessels, which controls both the type of lymphocyte and the site of entry into lymphoid tissues. Uniquely, HEVs express vascular addressins that regulate lymphocyte entry into lymphoid organs and are, therefore, critical to the function of lymphoid organs. Recent studies have demonstrated important roles for CD11c+ dendritic cells in the induction, as well as the maintenance, of vascular addressin expression and, therefore, the function of HEVs. Tertiary lymphoid organs (TLOs) are HEV containing LN-like structures that develop inside organized tissues undergoing chronic immune-mediated inflammation. In autoimmune lesions, the development of TLOs is thought to exacerbate disease. In cancerous tissues, the development of HEVs and TLOs is associated with improved patient outcomes in several cancers. Therefore, it is important to understand what drives the development of HEVs and TLOs and how these structures contribute to pathology. In several human diseases and experimental animal models of chronic inflammation, there are some similarities between the development and function of HEVs within LN and TLOs. This review will summarize current knowledge of how hemopoietic cells with lymphoid tissue-inducing, HEV-inducing, and HEV-maintaining properties are recruited from the bloodstream to induce the development and control the function of lymphoid organs.

Tertiary lymphoid structures, drivers of the anti-tumor responses in human cancers

The characterization of the microenvironment of human tumors led to the description of tertiary lymphoid structures (TLS) characterized by mature dendritic cells in a T-cell zone adjacent to B-cell follicle including a germinal center. TLS represent sites of lymphoid neogenesis that develop in most solid cancers. Analysis of the current literature shows that the TLS presence is associated with a favorable clinical outcome for cancer patients, regardless of the approach used to quantify TLS and the stage of the disease. Using several approaches that combine immunohistochemistry, gene expression assays, and flow cytometry on large series of lung tumors, our work demonstrated that TLS are important sites for the initiation and/or maintenance of the local and systemic T- and B-cell responses against tumors. Surrounded by high endothelial venules, they represent a privileged area for the recruitment of lymphocytes into tumors and generation of central-memory T and B cells that circulate and limit cancer progression. TLS can be considered as a novel biomarker to stratify the overall survival risk of untreated cancer patients and as a marker of efficient immunotherapies. The induction and manipulation of cancer-associated TLS using drug agonists and/or biotherapies should open new avenues to treat cancer patients.

The Role of Cancer-Associated Fibroblasts and Fibrosis in Liver Cancer

Liver cancer is the second leading cause of cancer mortality worldwide, causing more than 700,000 deaths annually. Because of the wide landscape of genomic alterations and limited therapeutic success of targeting tumor cells, a recent focus has been on better understanding and possibly targeting the microenvironment in which liver tumors develop. A unique feature of liver cancer is its close association with liver fibrosis. More than 80% of hepatocellular carcinomas (HCCs) develop in fibrotic or cirrhotic livers, suggesting an important role of liver fibrosis in the premalignant environment (PME) of the liver. Cholangiocarcinoma (CCA), in contrast, is characterized by a strong desmoplasia that typically occurs in response to the tumor, suggesting a key role of cancer-associated fibroblasts (CAFs) and fibrosis in its tumor microenvironment (TME). Here, we discuss the functional contributions of myofibroblasts, CAFs, and fibrosis to the development of HCC and CCA in the hepatic PME and TME, focusing on myofibroblast- and extracellular matrix-associated growth factors, fibrosis-associated immunosuppressive pathways, as well as mechanosensitive signaling cascades that are activated by increased tissue stiffness. Better understanding of the role of myofibroblasts in HCC and CCA development and progression may provide the basis to target these cells for tumor prevention or therapy.

Potential of Cells and Cytokines/Chemokines to Regulate Tertiary Lymphoid Structures in Human Diseases

Tertiary lymphoid structures (TLS) are ectopic lymphoid tissues involved in chronic inflammation, autoimmune diseases, transplant rejection and cancer. They exhibit almost all the characteristics of secondary lymphoid organs (SLO), which are associated with adaptive immune responses; as such, they contain organized B-cell follicles with germinal centers, distinct areas containing T cells and dendritic cells, high endothelial venules, and lymphatics. In this review, we briefly describe the formation of SLO, and describe the cellular subsets and molecular cues involved in the formation and maintenance of TLS. Finally, we discuss the associations of TLS with human diseases, especially autoimmune diseases, and the potential for therapeutic targeting.

Crosstalk between Innate Lymphoid Cells and Other Immune Cells in the Tumor Microenvironment

Our knowledge and understanding of the tumor microenvironment (TME) have been recently expanded with the recognition of the important role of innate lymphoid cells (ILC). Three different groups of ILC have been described based on their ability to produce cytokines that mediate the interactions between innate and adaptive immune cells in a variety of immune responses in infection, allergy, and autoimmunity. However, recent evidence from experimental models and clinical studies has demonstrated that ILC contribute to the mechanisms that generate suppressive or tolerant environments that allow tumor regression or progression. Defining the complex network of interactions and crosstalk of ILC with other immune cells and understanding the specific contributions of each type of ILC leading to tumor development will allow the manipulation of their function and will be important to develop new interventions and therapeutic strategies.

Chronic hepatitis C virus infection and pathogenesis of hepatocellular carcinoma

Hepatitis C virus (HCV) infection is one of the major causes of advanced liver disease and hepatocellular carcinoma (HCC) worldwide. While the knowledge about the molecular virology of HCV infection has markedly advanced, the molecular mechanisms of disease progression leading to fibrosis, cirrhosis and HCC are still unclear. Accumulating experimental and clinical studies indicate that HCV may drive hepatocarcinogenesis directly via its proteins or transcripts, and/or indirectly through induction of chronic liver inflammation. Despite the possibility to eradicate HCV infection through direct-acting antiviral treatment, the risk of HCC persists although specific biomarkers to estimate this risk are still missing. Thus, a better understanding of HCV-induced HCC and more physiological liver disease models are required to prevent cancer development.

Understanding Immune Cells in Tertiary Lymphoid Organ Development: It Is All Starting to Come Together

Tertiary lymphoid organs (TLOs) are frequently observed in tissues affected by non-resolving inflammation as a result of infection, autoimmunity, cancer, and allograft rejection. These highly ordered structures resemble the cellular composition of lymphoid follicles typically associated with the spleen and lymph node compartments. Although TLOs within tissues show varying degrees of organization, they frequently display evidence of segregated T and B cell zones, follicular dendritic cell networks, a supporting stromal reticulum, and high endothelial venules. In this respect, they mimic the activities of germinal centers and contribute to the local control of adaptive immune responses. Studies in various disease settings have described how these structures contribute to either beneficial or deleterious outcomes. While the development and architectural organization of TLOs within inflamed tissues requires homeostatic chemokines, lymphoid and inflammatory cytokines, and adhesion molecules, our understanding of the cells responsible for triggering these events is still evolving. Over the past 10–15 years, novel immune cell subsets have been discovered that have more recently been implicated in the control of TLO development and function. In this review, we will discuss the contribution of these cell types and consider the potential to develop new therapeutic strategies that target TLOs.

Tertiary Lymphoid Structures in Cancers: Prognostic Value, Regulation, and Manipulation for Therapeutic Intervention

Tertiary lymphoid structures (TLS) are ectopic lymphoid aggregates that reflect lymphoid neogenesis occurring in tissues at sites of inflammation. They are detected in tumors where they orchestrate local and systemic anti-tumor responses. A correlation has been found between high densities of TLS and prolonged patient's survival in more than 10 different types of cancer. TLS can be regulated by the same set of chemokines and cytokines that orchestrate lymphoid organogenesis and by regulatory T cells. Thus, TLS offer a series of putative new targets that could be used to develop therapies aiming to increase the anti-tumor immune response.

Lymphotoxin in physiology of lymphoid tissues - Implication for antiviral defense

Lymphotoxin (LT) is a member of the tumor necrosis factor (TNF) superfamily of cytokines which serves multiple functions, including the control of lymphoid organ development and maintenance, as well as regulation of inflammation and autoimmunity. Although the role of LT in organogenesis and maintenance of lymphoid organs is well established, the contribution of LT pathway to homeostasis of lymphoid organs during the immune response to pathogens is less understood. In this review, we highlight recent advances on the role of LT pathway in antiviral immune responses. We discuss the role of LT signaling in lymphoid organ integrity, type I IFN production and regulation of protection and immunopathology during viral infections. We further discuss the potential of therapeutic targeting LT pathway for controlling immunopathology and antiviral protection.