•Within the TME CAFs play an essential role in tumor progression.•CAFs are implicated in the induction of radioresistance.•Crosstalk between tumor cells, immune cells and CAFs dictates radiotherapy ...outcome.
Tumor growth is not only dictated by events involving tumor cells, but also by the environment they reside in, the so-called tumor microenvironment (TME). In the TME, cancer-associated fibroblasts (CAFs) are often the predominant cell type. CAFs were long considered to be of limited importance in the TME, but are now recognized for their pivotal role in cancer progression. Recently, it has become evident that different subsets of CAFs exist, with certain CAF subtypes having protumorigenic properties, whereas others show more antitumorigenic characteristics. Currently, the intricate interaction between the different subsets of CAFs with tumor cells, but also with immune cells that reside in the TME, is still poorly understood. This crosstalk of CAFs with tumor and immune cells in the TME largely dictates how a tumor responds to therapy and whether the tumor will eventually be eliminated, stay dormant or will progress and metastasize. Radiotherapy (RT) is a widely used and mostly very effective local cancer treatment, but CAFs are remarkably RT resistant. Although radiation does cause persistent DNA damage, CAFs do not die upon clinically applied doses of RT, but rather become senescent. Through the secretion of cytokines and growth factors they have been implicated in the induction of tumor radioresistance and recruitment of specific immune cells to the TME, thereby affecting local immune responses. In this review we will discuss the versatile role of CAFs in the TME and their influence on RT response.
Knockout (KO) mouse models play critical roles in elucidating biological processes behind disease-associated or disease-resistant traits. As a presumed consequence of gene KO, mice display certain ...phenotypes. Based on insight into the molecular role of said gene in a biological process, it is inferred that the particular biological process causally underlies the trait. This approach has been crucial towards understanding the basis of pathological and/or advantageous traits associated with
KO mice.
KO mice suffer from severe, early-onset retinal degeneration. MERTK, expressed in retinal pigment epithelia, is a receptor tyrosine kinase with a critical role in phagocytosis of apoptotic cells or cellular debris. Therefore, early-onset, severe retinal degeneration was described to be a direct consequence of failed MERTK-mediated phagocytosis of photoreceptor outer segments by retinal pigment epithelia. Here, we report that the loss of
alone is not sufficient for retinal degeneration. The widely used
KO mouse carries multiple coincidental changes in its genome that affect the expression of a number of genes, including the
paralog
. Retinal degeneration manifests only when the function of
is concomitantly lost. Furthermore,
KO mice display improved anti-tumor immunity. MERTK is expressed in macrophages. Therefore, enhanced anti-tumor immunity was inferred to result from the failure of macrophages to dispose of cancer cell corpses, resulting in a pro-inflammatory tumor microenvironment. The resistance against two syngeneic mouse tumor models observed in
KO mice is not, however, phenocopied by the loss of
alone. Neither
nor macrophage phagocytosis by alternate genetic redundancy accounts for the absence of anti-tumor immunity. Collectively, our results indicate that context-dependent epistasis of independent modifier alleles determines
KO traits.
BackgroundImmunotherapy is now considered as the new pillar in treatment of cancer patients. Dendritic cells (DCs) play an essential role in stimulating anti-tumor immune responses, as they are ...capable of cross-presenting exogenous tumor antigens in MHCI complexes to activate naïve CD8+ T cells. Analgesics, like non-steroid anti-inflammatory drugs (NSAIDs), are frequently given to cancer patients to help relieve pain, however little is known about their impact on DC function.MethodsHere, we investigated the effect of the NSAIDs diclofenac, ibuprofen and celecoxib on the three key processes of DCs required for proper CD8+ cytotoxic T cell induction: antigen cross-presentation, co-stimulatory marker expression, and cytokine production.ResultsOur results show that TLR-induced pro- and anti-inflammatory cytokine excretion by human monocyte derived and murine bone-marrow derived DCs is diminished after NSAID exposure.ConclusionsThese results indicate that various NSAIDs can affect DC function and warrant further investigation into the impact of NSAIDs on DC priming of T cells and cancer immunotherapy efficacy.
Basement membrane transmigration during embryonal development, tissue homeostasis and tumor invasion relies on invadosomes, a collective term for invadopodia and podosomes. An adequate structural ...framework for this process is still missing. Here, we reveal the modular actin nano-architecture that enables podosome protrusion and mechanosensing. The podosome protrusive core contains a central branched actin module encased by a linear actin module, each harboring specific actin interactors and actin isoforms. From the core, two actin modules radiate: ventral filaments bound by vinculin and connected to the plasma membrane and dorsal interpodosomal filaments crosslinked by myosin IIA. On stiff substrates, the actin modules mediate long-range substrate exploration, associated with degradative behavior. On compliant substrates, the vinculin-bound ventral actin filaments shorten, resulting in short-range connectivity and a focally protrusive, non-degradative state. Our findings redefine podosome nanoscale architecture and reveal a paradigm for how actin modularity drives invadosome mechanosensing in cells that breach tissue boundaries.
Background Immunotherapy is now considered as the new pillar in treatment of cancer patients. Dendritic cells (DCs) play an essential role in stimulating anti-tumor immune responses, as they are ...capable of cross-presenting exogenous tumor antigens in MHCI complexes to activate naïve CD8+ T cells. Analgesics, like non-steroid anti-inflammatory drugs (NSAIDs), are frequently given to cancer patients to help relieve pain, however little is known about their impact on DC function. Methods Here, we investigated the effect of the NSAIDs diclofenac, ibuprofen and celecoxib on the three key processes of DCs required for proper CD8+ cytotoxic T cell induction: antigen cross-presentation, co-stimulatory marker expression, and cytokine production. Results Our results show that TLR-induced pro- and anti-inflammatory cytokine excretion by human monocyte derived and murine bone-marrow derived DCs is diminished after NSAID exposure. Conclusions These results indicate that various NSAIDs can affect DC function and warrant further investigation into the impact of NSAIDs on DC priming of T cells and cancer immunotherapy efficacy.
Neoadjuvant therapy is the cornerstone of modern rectal cancer treatment. Insights into the biology of tumor responses are essential for the successful implementation of organ-preserving strategies, ...as different treatments may lead to specific tumor responses. In this study, we aim to explore treatment-specific responses of the tumor microenvironment. Patients with locally advanced adenocarcinoma of the rectum who had received neo-adjuvant chemotherapy (CT), neo-adjuvant radiochemotherapy (RCT), neo-adjuvant radiotherapy with a long-interval (LRT) or short-interval (SRT) or no neoadjuvant therapy (NT) as control were included. Multiplex-immunofluorescence was performed to determine the presence of cytotoxic T-cells (T-cyt; CD3+CD8+), regulatory T-cells (T-reg; CD3+FOXP3+), T-helper cells (T-helper; CD3+CD8-FOXP3-), B cells (CD20+), dendritic cells (CD11c+) and tumor cells (panCK+). A total of 80 rectal cancer patients were included. Treatment groups were matched for gender, tumor location, response to therapy, and TNM stage. The pattern of response (shrinkage
vs.
fragmentation) was, however, different between treatment groups. Our analyses reveal that RCT-treated patients exhibited lower stromal T-helper, T-reg, and T-cyt cells compared to other treatment regimens. In conclusion, we demonstrated treatment-specific differences in the immune microenvironment landscape of rectal cancer patients. Understanding the underlying mechanisms of this landscape after a specific therapy will benefit future treatment decisions.
Topical application of the vitamin D (VitD) analog calcipotriol is a highly effective standard treatment modality of psoriatic skin lesions. However, the immune modulatory effects of the treatment ...are incompletely understood. VitD is well known to induce tolerogenic responses in conventional dendritic cells (cDCs). Plasmacytoid DCs (pDCs) comprise a specialized, naturally occurring DC subset known to be important in autoimmune diseases including psoriasis. pDCs from the blood rapidly infiltrate psoriatic skin and are key to the initiation of the immune-mediated pathogenesis of the disease. We now demonstrate that pDCs express various proteins of the VitD receptor (VDR) pathway, including the VitD-metabolizing enzymes Cyp27B1 and Cyp24A1, and that VDR is transcriptionally active in pDCs. Moreover, VitD impairs the capacity of murine and human pDCs to induce T-cell proliferation and secretion of the T-helper 1 cytokine IFNγ. The inhibitory effect of VitD is dependent on the expression of the VDR in the DCs. This study demonstrates that VitD signaling can act as a natural inhibitory mechanism on both cDCs and pDCs, which may instigate the development of VitD-based therapeutic applications for psoriasis and other inflammatory skin diseases.
During the last years, preclinical and clinical studies have emerged supporting the rationale to integrate radiotherapy and immunotherapy. Radiotherapy may enhance the effects of immunotherapy by ...improving tumor antigen release, antigen presentation, and T-cell infiltration. Recently, magnetic resonance guided radiotherapy (MRgRT) has become clinically available. Compared to conventional radiotherapy techniques, MRgRT firstly allows for daily on-table treatment adaptation, which enables both dose escalation for increasing tumor response and superior sparing of radiosensitive organs-at-risk for reducing toxicity. The current review focuses on the potential of combining MR-guided adaptive radiotherapy with immunotherapy by providing an overview on the current status of MRgRT, latest developments in preclinical and clinical radio-immunotherapy, and the unique opportunities and challenges for MR-guided radio-immunotherapy. MRgRT might especially assist in answering open questions in radio-immunotherapy regarding optimal radiation dose, fractionation, timing of immunotherapy, appropriate irradiation volumes, and response prediction.
Current multimodal treatments for patients with neuroblastoma (NBL), including anti‐disialoganglioside (GD2) monoclonal antibody (mAb) based immunotherapy, result in a favorable outcome in around ...only half of the patients with advanced disease. To improve this, novel immunocombinational strategies need to be developed and tested in autologous preclinical NBL models. A genetically well‐explored autologous mouse model for NBL is the TH‐MYCN model. However, the immunobiology of the TH‐MYCN model remains largely unexplored. We developed a mouse model using a transplantable TH‐MYCN cell line in syngeneic C57Bl/6 mice and characterized the immunobiology of this model. In this report, we show the relevance and opportunities of this model to study immunotherapy for human NBL. Similar to human NBL cells, syngeneic TH‐MYCN‐derived 9464D cells endogenously express the tumor antigen GD2 and low levels of MHC Class I. The presence of the adaptive immune system had little or no influence on tumor growth, showing the low immunogenicity of the NBL cells. In contrast, depletion of NK1.1+ cells resulted in enhanced tumor outgrowth in both wild‐type and Rag1−/− mice, showing an important role for NK cells in the natural anti‐NBL immune response. Analysis of the tumor infiltrating leukocytes ex vivo revealed the presence of both tumor associated myeloid cells and T regulatory cells, thus mimicking human NBL tumors. Finally, anti‐GD2 mAb mediated NBL therapy resulted in ADCC in vitro and delayed tumor outgrowth in vivo. We conclude that the transplantable TH‐MYCN model represents a relevant model for the development of novel immunocombinatorial approaches for NBL patients.
What's new?
Natural killer (NK) cells may serve a role in immune defense against neuroblastoma, though limitations in existing models have prevented extensive study of the immunological characteristics of the disease. Here, to better understand the immunobiology of neuroblastoma, the TH‐MYCN mouse model was adapted for immunological investigation. Tumor cells (9464D) derived from immunologically compatible C57Bl/6 TH‐MYCN mice were found to express the tumor antigen GD2. In addition, depletion of NK cells was associated with tumor outgrowth in both wild‐type and Rag1‐/‐ C57Bl/6 mice, whereas immunotherapy targeted against GD2 decreased tumor growth.
In the last decade, organoid technology has developed as a primary research tool in basic biological and clinical research. The reliance on poorly defined animal‐derived extracellular matrix, ...however, severely limits its application in regenerative and translational medicine. Here, a well‐defined, synthetic biomimetic matrix based on polyisocyanide (PIC) hydrogels that support efficient and reproducible formation of mammary gland organoids (MGOs) in vitro is presented. Only decorated with the adhesive peptide RGD for cell binding, PIC hydrogels allow MGO formation from mammary fragments or from purified single mammary epithelial cells. The cystic organoids maintain their capacity to branch for over two months, which is a fundamental and complex feature during mammary gland development. It is found that small variations in the 3D matrix give rise to large changes in the MGO: the ratio of the main cell types in the MGO is controlled by the cell–gel interactions via the cell binding peptide density, whereas gel stiffness controls colony formation efficiency, which is indicative of the progenitor density. Simple hydrogel modifications will allow for future introduction and customization of new biophysical and biochemical parameters, making the PIC platform an ideal matrix for in depth studies into organ development and for application in disease models.
A fully synthetic and highly tailorable matrix material is presented that supports the formation of organoids. With minimal adhesive peptide functionalization, this polyisocyanide hydrogel allows single cells to develop into mammary gland organoids. As tuning the hydrogel properties controls organoid composition, future customization will set the stage for improved control of organoid production and in‐depth studies into organ development.
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