Inverse correlation between metastatic load and immune infiltration

Digestive diseases comprise a diverse range of illnesses, which are prevalent worldwide and represent an important health issue. This is particularly relevant for the impact of metabolic dysfunction-associated steatotic liver disease (MASLD) due to its close association with the obesity pandemic, contributing to the escalation of MASLD as the most common form of chronic liver disease, and the main cause of liver cancer. Not only does MASLD reflect the deterioration of liver health, but it also has far-reaching consequences for the development of extrahepatic digestive diseases. Along with the progression of liver and digestive diseases to liver, colorectal and pancreatic cancer, the onset of inflammation in diseases of the digestive tract, drug-induced liver injury, and cholestasis, drives and contributes to the rise of these diseases in the future, which merit the attention of clinical and translational research to increase our understanding of the pathogenic mechanisms underlying these disorders in order to improve the diagnosis, management, and treatment. With this goal in mind, the current collaborative review gathers experts in a wide range of liver and digestive diseases to provide an up-to-date overview of the mechanisms of disease and identify novel strategies for the improvement of these important health issues.

Number of resident and migratory cDCs is unchanged in the tumor-draining lymph nodes of metastases-bearing TYK2-/- host mice

Immunophenotyping of established metastases by flow cytometry in TYK2-/- and TYK2Δhem host mice

Colorectal cancer liver metastasis (CRLM) is a major clinical problem. The regulators of immunosurveillance of CRLM could hold potential for developing therapeutic strategies to prevent or treat metastasis. In this study, using a murine colorectal cancer organoid-based transplantation model, we identified TYK2 as a key factor controlling CRLM. Evaluation of the effects of Tyk2 deletion in different subsets of immune cells and in colorectal cancer cells demonstrated that TYK2 was not required in cancer cells, macrophages, NK cells, T cells, or Kupffer cells. Instead, TYK2 controlled CRLM via a dendritic cell-dependent mechanism that relied on MHC-I-mediated cross-presentation of antigens to CD8+ T cells. Analysis of single-cell RNA sequencing data from primary colorectal cancer and CRLM revealed that TYK2 was predominantly expressed in a dendritic cell population destined to present antigens in tumor-draining lymph nodes. Treatment with the TYK2 inhibitor deucravacitinib, which is approved by the FDA for treating plaque psoriasis and is under clinical investigation for other autoimmune diseases, promoted CRLM. Together, these data demonstrate that TYK2 controls CRLM immunosurveillance, which should be carefully considered when treating patients with TYK2 inhibitors.Significance: TYK2 restricts the metastasis of colorectal tumors to the liver by supporting dendritic cell-dependent induction of antitumor CD8+ T cells, which could impact the use of TYK2 inhibitors in patients.

mRNA expression of cytokines, chemokines, costimulatory molecules and immune checkpoints in healthy and metastases-bearing livers of TYK2flox/flox and TYK2Δhem host mice

BACKGROUND:Prostate cancer ranks as the second most frequently diagnosed cancer in men worldwide. Recent research highlights the crucial roles IL6ST-mediated signaling pathways play in the development and progression of various cancers, particularly through hyperactivated STAT3 signaling. However, the molecular programs mediated by IL6ST/STAT3 in prostate cancer are poorly understood. METHODS:To investigate the role of IL6ST signaling, we constitutively activated IL6ST signaling in the prostate epithelium of a Pten-deficient prostate cancer mouse model in vivo and examined IL6ST expression in large cohorts of prostate cancer patients. We complemented these data with in-depth transcriptomic and multiplex histopathological analyses. RESULTS:Genetic cell-autonomous activation of the IL6ST receptor in prostate epithelial cells triggers active STAT3 signaling and significantly reduces tumor growth in vivo. Mechanistically, genetic activation of IL6ST signaling mediates senescence via the STAT3/ARF/p53 axis and recruitment of cytotoxic T-cells, ultimately impeding tumor progression. In prostate cancer patients, high IL6ST mRNA expression levels correlate with better recurrence-free survival, increased senescence signals and a transition from an immune-cold to an immune-hot tumor. CONCLUSIONS:Our findings demonstrate a context-dependent role of IL6ST/STAT3 in carcinogenesis and a tumor-suppressive function in prostate cancer development by inducing senescence and immune cell attraction. We challenge the prevailing concept of blocking IL6ST/STAT3 signaling as a functional prostate cancer treatment and instead propose cell-autonomous IL6ST activation as a novel therapeutic strategy.

Altered immunophenotype of micrometastatic lesions in TYK2Δhem host mice

Expression of TYK2 in human CRC-derived LAMP3+ CCR7+ cDCs

Tyk2 deletion in AKP organoids has no effect on CRLM

TYK2 deficiency in host mice promotes liver metastasis of AKP organoids seeded via the portal vein

Evaluation of TYK2 deletion in conditional mouse models

The increasing prevalence of inflammatory bowel disease (IBD) and rising pollution from micro- and nanoplastic (MNP) particles has prompted investigations on their potential interconnection. To elucidate the complex relationship between IBD and exposure to MNPs, we induced colitis in mice using dextran sodium sulfate (DSS) and orally administered a mixture of polystyrene (PS) MNPs (diameter 10, 1, and 0.29 µm). These particles enabled a detailed examination of MNP biodistribution, innate immune cell response and gut microbiome alterations under inflammatory conditions. Specifically, the nanosized PS particles predominantly accumulated in the bloodstream and excretory organs, with enhanced accumulation in the inflamed gut/colon. Proteomic analysis of the colon revealed alterations in molecular pathways related to protein transport, metabolism, and immune responses. Specifically, we found macrophage proteome signatures with pro-inflammatory polarization, highlighting the intricate effects of MNPs on inflammation and immune cell behavior. Moreover, MNPs significantly disrupted the gut microbiome, reducing microbial diversity and shifting bacterial populations towards pro-inflammatory and potentially pathogenic species. These changes suggest that MNP exposure could exacerbate colitis through complex interactions involving MNPs, immune responses, and microbial dynamics. The widespread presence of MNPs underscores the urgent need for comprehensive strategies to address MNP pollution, its implications for disease, and potential impacts on public health.

BACKGROUND:Enhanced protein expression of ALL1-fused gene from chromosome 1q (AF1Q) after (chemo)radiotherapy has been described in vitro, but is largely understudied in gastrointestinal cancer. We aimed to investigate AF1q expression in rectal cancer (RC) patients treated with short-term radiation therapy and a possible correlation with markers crucial for RC prognosis. METHODS:A cohort of 75 RC patients scheduled for surgery was defined and patients with moderately locally advanced tumors (cT3Nx) received preoperative hyperfractionated short-term radiation therapy (cumulative dose 25 Gy). Immunohistochemical analysis was conducted to assess AF1q, STAT1, IDO1 and other prognostic markers (CD3/CD8-Immunoscore, PD-L1) and marker correlations were evaluated. RESULTS:Irradiated tumors exhibited significantly higher AF1q expression than treatment-naïve samples (n = 60: AF1q + to AF1q+++ 98.3% (n = 59), AF1q- 1.7% (n = 1) vs. n = 15: AF1q + 78.6% (n = 11), AF1q- 21.4% (n = 4); p < 0.001). Specifically, irradiated tumors showed high STAT1, but low IDO1 expression compared to treatment-naïve samples (p = 0.019 and p = 0.015, respectively). Overall, enhanced tumoral AF1q expression was associated with negative lymph node stage (p = 0.012) as well as with diminished expression of STAT1 (rs = -0.468, p = 0.038) and IDO1 (rs = -0.246, p = 0.020). CONCLUSION:AF1q is expressed in RC, especially after short-term radiation therapy. Here, AF1q may support tumor suppression, possibly through the involvement of the pro-apoptotic STAT1 axis. Further mechanistic evidence and investigation involving a larger patient cohort are needed to validate a radiation-induced, AF1q-driven tumor-suppressing effect, which may impact RC patient outcomes.

Inflammation is a widely recognized key contributor to KRAS-driven lung adenocarcinoma (LUAD). Tumor-associated macrophages (TAM) are an integral part of the tumor microenvironment and create a supportive niche that sustains inflammation-driven tumorigenesis. In the present study, we unravel a dual role of sphingosine kinase 1 (SPHK1) in KRAS-driven LUAD. While SPHK1 promotes tumorigenesis in in vitro experimental models, it paradoxically suppresses tumorigenesis in in vivo models of KRAS-mutated LUAD. Mechanistically, tumor-intrinsic loss of SPHK1 leads to disrupted lipid homeostasis, increased inflammation and infiltration by TAM, ultimately driving tumor progression. Thus, our study suggests that clinically targeting the SPHK1/S1P axis could potentially result in increased tumor progression, possibly by rewiring the tumor microenvironment toward a more inflammatory and pro-tumorigenic state.

Abstract Introduction: Lung cancer is the leading cause of death worldwide. One third of lung adenocarcinomas (LUADs), the most abundant form of lung cancer, harbors activating mutations in KRAS. Since human KRAS-mutant LUAD is correlated to an inflammatory phenotype, we hypothesized that the JAK-STAT pathway plays a crucial role in disease progression. Indeed, preliminary data demonstrated that human KRAS-mutant LUADs are associated with activation of the JAK-STAT signaling pathway, including upregulation of STAT1 expression. Therefore, we aimed to elucidate the tumorigenic functions of STAT1 in KRAS-mutant LUAD. Methods: To analyze the functions of STAT1 in KRAS-driven LUAD, we used C57BL/6 mice, which were genetically engineered in order to develop KRAS-driven autochthonous LUAD deficient for P53. Tumors additionally expressed ovalbumin (OVA) which acts as a neoantigen to induce immune infiltration (KPO mice). In this immunogenic mouse model, STAT1 was deleted in the tumors (KPOS mice) and overall survival was assessed by Kaplan Meier analysis. Tumor burden and infiltration was analyzed in lungs via H&E, IHC, and IF staining 6 weeks after tumor induction. An inflammatory cytokine antibody array was performed with lung fluid and single cell sequencing with cells isolated from lungs at 10 weeks. Results and discussion: Expression of OVA in tumor cells increased infiltration by T cells and prolonged survival suggesting neoantigen presentation in this mouse model. When STAT1 was deleted in OVA expressing tumors the survival was significantly decreased. Further, tumor burden as well as tumor size and grades were increased in KPOS lungs. Interestingly, infiltration of CD4 T cells was diminished upon loss of STAT1 while the percentage of CD8 T cells in tumors did not change suggesting an immunosuppressive tumor microenvironment. Indeed, M2 macrophages were increased in tumors lacking STAT1 and less proliferating immune cells were found indicating immune cell inhibition. This was further supported by the increase of CCL9 in KPOS lungs which might induce macrophage recruitment and further T cell inhibition. Finally, scRNAseq analysis revealed that KPOS lungs were composed of distinct immune cell populations as well as states. Conclusion: This data suggests that loss of STAT1 in tumor cells promotes secretion of CCL9 that drives recruitment of immunosuppressive macrophages to the tumor microenvironment. As a result, T helper cells are excluded from tumors and cytotoxic T cells are inhibited or exhausted. Further experiments will delineate the immune cell states and the mechanisms leading to this interesting phenotype. Citation Format: Christoph Trenk, Maša Bereš, Katalin Deszo, Jaqueline Horvath, Monika Homolya, Andreea Corina Luca, Robert Eferl, Herwig Peter Moll, Emilio Casanova. Loss of STAT1 promotes an immunosuppressive tumor microenvironment in KRAS-driven lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6862.

Background The increasing prevalence of inflammatory bowel disease (IBD) and rising pollution from micro- and nanoplastic (MNP) particles has prompted investigations on their potential interconnection. To elucidate the complex relationship between IBD and exposure to MNPs, we induced colitis in mice using dextran sodium sulfate (DSS) and orally administered a solution of differently sized polystyrene (PS) MNPs (diameter 10, 1, and 0.29 µm). These particles facilitated a detailed examination of MNP biodistribution, macrophage response, and gut microbiome alterations under inflammatory conditions. Results Specifically nanosized PS particles accumulated in the bloodstream and excretory organs, with enhanced accumulation in the colitis model. Macrophages shifted towards a pro-inflammatory phenotype, with decreased anti-inflammatory markers highlighting the intricate effects of MNPs on inflammation and immune cell behavior. Moreover, MNPs significantly disrupted the gut microbiome, reducing microbial diversity and shifting bacterial populations towards pro-inflammatory and potentially pathogenic species. Conclusions These changes suggest that MNP exposure could exacerbate colitis through complex interactions involving MNPs, immune responses, and microbial dynamics. The fast growing exposure to MNPs underscores the urgent need for comprehensive public health strategies to address MNP pollution, its implications for disease and potential impacts on public health.

Metastatic colorectal cancer is one of the leading causes of cancer-related deaths worldwide. Traditional chemotherapy extended the lifespan of cancer patients by only a few months, but targeted therapies and immunotherapy prolonged survival and led to long-term remissions in some cases. Type I and II interferons have direct pro-apoptotic and anti-proliferative effects on cancer cells and stimulate anti-cancer immunity. As a result, interferon production by cells in the tumor microenvironment is in the spotlight of immunotherapies as it affects the responses of anti-cancer immune cells. However, promoting effects of interferons on colorectal cancer metastasis have also been reported. Here we summarize our knowledge about pro- and anti-metastatic effects of type I and II interferons in colorectal cancer liver metastasis and discuss possible therapeutic implications.

Lung cancer is responsible for the majority of cancer-related deaths worldwide. Within this severe disease lung adenocarcinoma (LUAD) belongs to the most common form of lung cancer. LUAD is highly correlated with KRAS mutations. Although, the first KRAS inhibitors entered into clinics recently, therapy resistance arises. Since KRAS-mutant LUAD is an inflammation driven disease, we focus on the JAK-STAT pathway as an alternative target. Preliminary data suggests that human KRAS-mutant LUAD is correlated to enriched JAK-STAT signaling, as well as STAT1 upregulation. Accordingly, we aimed to explore the tumorigenic functions of STAT1 in this form of lung cancer. Genetically engineered C57BL6/N mice which develop autochthonous KRAS-driven and P53-deficient LUAD proficient (KP) and deficient for STAT1 (KPS) were used. In a second mouse model expression of ovalbumin was induced in tumor cells, mimicking a neoantigen to increase immune infiltration in the presence (KPO) or absence of STAT1 (KPOS). Kaplan-Meyer analysis was performed to assess the overall survival. Tumor burden, as well as immune infiltration was analyzed in lungs 6 and 10 weeks after tumor induction via H&E, IHC and IF staining. Furthermore, the lung fluid was collected by bronchoalveolar lavage and used to profile inflammatory cytokines. Deletion of STAT1 reduced the survival in KRAS-driven LUAD mice only when ovalbumin was expressed. Tumor burden and tumor grades were increased in tumors lacking STAT1 at 6 and 10 weeks after tumor initiation. Surprisingly, although tumors of KPOS mice showed a decreased infiltration by T cells and CD4 T cells, CD8 T cell infiltration did not change, suggesting a tumor suppressive function of STAT1 via T cell exhaustion. Moreover, the macrophage attracting cytokine CCL9 secretion was upregulated and the number of tumor infiltrating, immunosuppressive macrophages was increased in KPOS mice. This data implicates a tumor suppressive function of STAT1 by secretion of cytokines that can recruit suppressive myeloid immune cells to the TME leading to CD4 T cell exclusion and CD8 T cell exhaustion. Further studies are needed on the changes in the immune infiltrating cells to explain the mechanism behind these intriguing findings. Citation Format: Christoph Trenk, Rebecca Sagmeister, Jaqueline Horvath, Monika Homolya, Andreea Corina Luca, Robert Eferl, Herwig Moll, Emilio Casanova. STAT1 suppresses KRAS-driven lung adenocarcinoma depending on the tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3650.

Intestinal epithelial cells are covered by the brush border, which consists of densely packed microvilli. The Intermicrovillar Adhesion Complex (IMAC) links the microvilli and is required for proper brush border organization. Whether microvillus crosslinking is involved in the intestinal barrier function or colitis is currently unknown. We investigate the role of microvillus crosslinking in colitis in mice with deletion of the IMAC component CDHR5. Electron microscopy shows pronounced brush border defects in CDHR5-deficient mice. The defects result in severe mucosal damage after exposure to the colitis-inducing agent DSS. DSS increases the permeability of the mucus layer and brings bacteria in direct contact with the disorganized brush border of CDHR5-deficient mice. This correlates with bacterial invasion into the epithelial cell layer which precedes epithelial apoptosis and inflammation. Single-cell RNA sequencing data of patients with ulcerative colitis reveals downregulation of CDHR5 in enterocytes of diseased areas. Our results provide experimental evidence that a combination of microvillus crosslinking defects with increased permeability of the mucus layer sensitizes to inflammatory bowel disease.