COX-2 inhibition alters the phenotype of tumor-associated macrophages from M2 to M1 in ApcMin/+ mouse polyps

Current understanding on TREM-2 molecular biology and physiopathological functions

Triggering receptor expressed on myeloid cells 2 (TREM-2), a glycosylated receptor belonging to the immunoglobin superfamily and especially expressed in the myeloid cell lineage, is frequently explained as a reminiscent receptor for both adaptive and innate immunity regulation. TREM-2 is also acknowledged to influence NK cell differentiation via the PI3K and PLCγ signaling pathways, as well as the partial activation or direct inhibition of T cells. Additionally, TREM-2 overexpression is substantially linked to cell-specific functions, such as enhanced phagocytosis, reduced toll-like receptor (TLR)-mediated inflammatory cytokine production, increased transcription of anti-inflammatory cytokines, and reshaped T cell function. Whereas TREM-2-deficient cells exhibit diminished phagocytic function and enhanced proinflammatory cytokines production, proceeding to inflammatory injuries and an immunosuppressive environment for disease progression. Despite the growing literature supporting TREM-2+ cells in various diseases, such as neurodegenerative disorders and cancer, substantial facets of TREM-2-mediated signaling remain inadequately understood relevant to pathophysiology conditions. In this direction, herein, we have summarized the current knowledge on TREM-2 biology and cell-specific TREM-2 expression, particularly in the modulation of pivotal TREM-2-dependent functions under physiopathological conditions. Furthermore, molecular regulation and generic biological relevance of TREM-2 are also discussed, which might provide an alternative approach for preventing or reducing TREM-2-associated deformities. At last, we discussed the TREM-2 function in supporting an immunosuppressive cancer environment and as a potential drug target for cancer immunotherapy. Hence, summarized knowledge of TREM-2 might provide a window to overcome challenges in clinically effective therapies for TREM-2-induced diseases in humans.

Inflammation and cancer: friend or foe?

Chronic inflammation plays a crucial role in the onset and progression of pathologies like neurodegenerative and cardiovascular diseases, diabetes, and cancer, since tumor development and chronic inflammation are linked, sharing common signaling pathways. At least 20% of breast and colorectal cancers are associated with chronic inflammation triggered by infections, irritants, or autoimmune diseases. Obesity, chronic inflammation, and cancer interconnection underscore the importance of population-based interventions in maintaining healthy body weight, to disrupt this axis. Given that the dietary inflammatory index is correlated with an increased risk of cancer, adopting an anti-inflammatory diet supplemented with nutraceuticals may be useful for cancer prevention. Natural products and their derivatives offer promising antitumor activity with favorable adverse effect profiles; however, the development of natural bioactive drugs is challenging due to their variability and complexity, requiring rigorous research processes. It has been shown that combining anti-inflammatory products, such as non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and statins, with plant-derived products demonstrate clinical utility as accessible adjuvants to traditional therapeutic approaches, with known safety profiles. Pharmacological approaches targeting multiple proteins involved in inflammation and cancer pathogenesis emerge as a particularly promising option. Given the systemic and multifactorial nature of inflammation, comprehensive strategies are essential for long term success in cancer therapy. To gain insights into carcinogenic phenomena and discover diagnostic or clinically relevant biomarkers, is pivotal to understand genetic variability, environmental exposure, dietary habits, and TME composition, to establish therapeutic approaches based on molecular and genetic analysis. Furthermore, the use of endocannabinoid, cannabinoid, and prostamide-type compounds as potential therapeutic targets or biomarkers requires further investigation. This review aims to elucidate the role of specific etiological agents and mediators contributing to persistent inflammatory reactions in tumor development. It explores potential therapeutic strategies for cancer treatment, emphasizing the urgent need for cost-effective approaches to address cancer-associated inflammation.

Deregulation of interferon-gamma receptor 1 expression and its implications for lung adenocarcinoma progression

Interferon-gamma (IFN-γ) plays a dual role in cancer; it is both a pro- and an antitumorigenic cytokine, depending on the type of cancer. The deregulation of the IFN-γ canonic pathway is associated with several disorders, including vulnerability to viral infections, inflammation, and cancer progression. In particular, the interplay between lung adenocarcinoma (LUAD) and viral infections appears to exist in association with the deregulation of IFN-γ signaling. In this mini-review, we investigated the status of the IFN-γ signaling pathway and the expression level of its components in LUAD. Interestingly, a reduction in IFNGR1 expression seems to be associated with LUAD progression, affecting defenses against viruses such as severe acute respiratory syndrome coronavirus 2. In addition, alterations in the expression of IFNGR1 may inhibit the antiproliferative action of IFN-γ signaling in LUAD.

Cathepsin D promotes polarization of tumor-associated macrophages and metastasis through TGFBI-CCL20 signaling

M2-like tumor-associated macrophages (TAMs) are risk factors for cancer progression and metastasis. However, the mechanisms underlying their polarization are still not fully understood. Although cathepsin D (Cat D) has been reported as a procarcinogenic factor, little is known about the functional role of Cat D in the tumor microenvironment (TME). This study aimed to explore the effect and molecular mechanisms of Cat D in the TME. Cat D knockout (KO) altered the cytokine secretion pattern and induced TAM reprogramming from the M2 to M1 subtype, thereby preventing epithelial-mesenchymal transition and tumor metastasis. Mechanistically, we identified transforming growth factor beta-induced protein (TGFBI) as a Cat D target protein that is specifically associated with TAM polarization. Elevated TGFBI expression in Cat D KO cancer cells resulted in a decline in M2-like TAM polarization. Our RNA-sequencing results indicated that the cancer cell-secreted chemokine CCL20 is a major secretory chemokine for Cat D-TGFBI-mediated TAM polarization. In contrast, Cat D overexpression accelerated TAM polarization into M2-like cells by suppressing TGFBI expression. In addition, the double Cat D and TGFBI KO rescued the inhibitory effects of Cat D KO on tumor metastasis by controlling TAM and T-cell activation. These findings indicated that Cat D contributes to cancer metastasis through TGFBI-mediated TAM reprogramming. Cat D deletion inhibits M2-like TAM polarization through TGFBI-mediated CCL20 expression, reprogramming the immunosuppressive TME. Our results open a potential new avenue for therapy focused on eliminating tumor metastasis.

Celecoxib and cisplatin dual-loaded microspheres synergistically enhance transarterial chemoembolization effect of hepatocellular carcinoma

Transarterial chemoembolization (TACE) is a first-line treatment for intermediate to advanced-stage liver cancer, with drug-eluting microspheres commonly used as embolic agents. However, currently available drug-eluting microspheres suffer from low drug-loading capacity and limited drug options. In this work, we developed polydopamine-modified polyvinyl alcohol dual-drug-loaded microspheres encapsulating celecoxib and cisplatin (referred to as PCDMS). Physicochemical characterization revealed that the surface of the microspheres displayed increased roughness after polydopamine modification, and celecoxib and cisplatin were successfully loaded onto the microsphere surface. In vitro cell experiments demonstrated that the PCDMS significantly inhibited the proliferation and migration of highly metastatic human liver cancer cells (MHCC-97H) and human liver cancer cells (SMMC-7721). Furthermore, the dual-loaded microspheres exhibited remarkable tumor growth inhibition and reshaped the tumor microenvironment in both subcutaneous H22 liver cancer model in Balb/c mice and intrahepatic VX2 tumor model in New Zealand rabbits, demonstrating a synergistic antitumor effect where 1 + 1>2. This work provides a potential therapeutic approach for the treatment of refractory liver cancer and holds significant translational potential.

Tumor-associated macrophages in colorectal cancer metastasis: molecular insights and translational perspectives

Metastasis is the leading cause of high mortality in colorectal cancer (CRC), which is not only driven by changes occurring within the tumor cells, but is also influenced by the dynamic interaction between cancer cells and components in the tumor microenvironment (TME). Currently, the exploration of TME remodeling and its impact on CRC metastasis has attracted increasing attention owing to its potential to uncover novel therapeutic avenues. Noteworthy, emerging studies suggested that tumor-associated macrophages (TAMs) within the TME played important roles in CRC metastasis by secreting a variety of cytokines, chemokines, growth factors and proteases. Moreover, TAMs are often associated with poor prognosis and drug resistance, making them promising targets for CRC therapy. Given the prognostic and clinical value of TAMs, this review provides an updated overview on the origin, polarization and function of TAMs, and discusses the mechanisms by which TAMs promote the metastatic cascade of CRC. Potential TAM-targeting techniques for personalized theranostics of metastatic CRC are emphasized. Finally, future perspectives and challenges for translational applications of TAMs in CRC development and metastasis are proposed to help develop novel TAM-based strategies for CRC precision medicine and holistic healthcare.

A moderate dosage of prostaglandin E2-mediated annexin A1 upregulation promotes alkali-burned corneal repair

Corneal alkali burn remains a clinical challenge in ocular emergency, necessitating the development of effective therapeutic drugs. Here, we observed the arachidonic acid metabolic disorders of corneas induced by alkali burns and aimed to explore the role of Prostaglandin E2 (PGE2), a critical metabolite of arachidonic acid, in the repair of alkali-burned corneas. We found a moderate dosage of PGE2 promoted the alkali-burned corneal epithelial repair, whereas a high dosage of PGE2 exhibited a contrary effect. This divergent effect is attributed to different dosages of PGE2 regulating ANXA1 expression differently. Mechanically, a high dosage of PGE2 induced higher GATA3 expression, followed by enhanced GATA3 binding to the ANXA1 promoter to inhibit ANXA1 expression. In contrast, a moderate dosage of PGE2 increased CREB1 phosphorylation and reduced GATA3 binding to the ANXA1 promoter, promoting ANXA1 expression. We believe PGE2 and its regulatory target ANXA1 could be potential drugs for alkali-burned corneas.

Drug Repurposing to Circumvent Immune Checkpoint Inhibitor Resistance in Cancer Immunotherapy

Immune checkpoint inhibitors (ICI) have achieved unprecedented clinical success in cancer treatment. However, drug resistance to ICI therapy is a major hurdle that prevents cancer patients from responding to the treatment or having durable disease control. Drug repurposing refers to the application of clinically approved drugs, with characterized pharmacological properties and known adverse effect profiles, to new indications. It has also emerged as a promising strategy to overcome drug resistance. In this review, we summarized the latest research about drug repurposing to overcome ICI resistance. Repurposed drugs work by either exerting immunostimulatory activities or abolishing the immunosuppressive tumor microenvironment (TME). Compared to the de novo drug design strategy, they provide novel and affordable treatment options to enhance cancer immunotherapy that can be readily evaluated in the clinic. Biomarkers are exploited to identify the right patient population to benefit from the repurposed drugs and drug combinations. Phenotypic screening of chemical libraries has been conducted to search for T-cell-modifying drugs. Genomics and integrated bioinformatics analysis, artificial intelligence, machine and deep learning approaches are employed to identify novel modulators of the immunosuppressive TME.

Lipid Metabolic Regulatory Crosstalk Between Cancer Cells and Tumor-Associated Macrophages

In the tumor microenvironment, tumor-associated macrophages (TAMs) are one of the most abundant cell populations, playing key roles in tumorigenesis, chemoresistance, immune evasion, and metastasis. There is an important interaction between TAMs and cancer cells: on the one hand, tumors control the function of infiltrating macrophages, contributing to reprogramming of TAMs, and on the other hand, TAMs affect the growth of cancer cells. This review focuses on lipid metabolism changes in the complex relationship between cancer cells and TAMs. We discuss how lipid metabolism in cancer cells affects macrophage phenotypic and metabolic changes and, subsequently, how altered lipid metabolism of TAMs influences tumor progression. Identifying the metabolic changes that influence the complex interaction between tumor cells and TAMs is also an important step in exploring new therapeutic approaches that target metabolic reprogramming of immune cells to enhance their tumoricidal potential and bypass therapy resistance. Our work may provide new targets for antitumor therapies.

Targeting Transcription Factor YY1 for Cancer Treatment: Current Strategies and Future Directions

Cancer represents a significant and persistent global health burden, with its impact underscored by its prevalence and devastating consequences. Whereas numerous oncogenes could contribute to cancer development, a group of transcription factors (TFs) are overactive in the majority of tumors. Targeting these TFs may also combat the downstream oncogenes activated by the TFs, making them attractive potential targets for effective antitumor therapeutic strategy. One such TF is yin yang 1 (YY1), which plays crucial roles in the development and progression of various tumors. In preclinical studies, YY1 inhibition has shown efficacy in inhibiting tumor growth, promoting apoptosis, and sensitizing tumor cells to chemotherapy. Recent studies have also revealed the potential of combining YY1 inhibition with immunotherapy for enhanced antitumor effects. However, clinical translation of YY1-targeted therapy still faces challenges in drug specificity and delivery. This review provides an overview of YY1 biology, its role in tumor development and progression, as well as the strategies explored for YY1-targeted therapy, with a focus on their clinical implications, including those using small molecule inhibitors, RNA interference, and gene editing techniques. Finally, we discuss the challenges and current limitations of targeting YY1 and the need for further research in this area.

Dual identity of tumor-associated macrophage in regulated cell death and oncotherapy

Tumor-associated macrophage (TAM) affects the intrinsic properties of tumor cells and the tumor microenvironment (TME), which can stimulate tumor cell proliferation, migration, and genetic instability, and macrophage diversity includes the diversity of tumors with different functional characteristics. Macrophages are now a central drug target in various diseases, especially in the TME, which, as "tumor promoters" and "immunosuppressors", have different responsibilities during tumor development and accompany by significant dynamic alterations in various subpopulations. Remodelling immunosuppression of TME and promotion of pre-existing antitumor immune responses is critical by altering TAM polarization, which is relevant to the efficacy of immunotherapy, and uncovering the exact mechanism of action of TAMs and identifying their specific targets is vital to optimizing current immunotherapies. Hence, this review aims to reveal the triadic interactions of macrophages with programmed death and oncotherapy, and to integrate certain relationships in cancer treatment.

Type 1 and type 2 cytokine-mediated immune orchestration in the tumour microenvironment and their therapeutic potential

Cancer remains the second leading cause of death worldwide despite modern breakthroughs in medicine, and novel treatments are urgently needed. The revolutionary success of immune checkpoint inhibitors in the past decade serves as proof of concept that the immune system can be effectively harnessed to treat cancer. Cytokines are small signalling proteins with critical roles in orchestrating the immune response and have become an attractive target for immunotherapy. Type 1 immune cytokines, including interferon γ (IFNγ), interleukin-12 (IL-12), and tumour necrosis factor α (TNFα), have been shown to have largely tumour suppressive roles in part through orchestrating anti-tumour immune responses mediated by natural killer (NK) cells, CD8⁺ T cells and T helper 1 (Th1) cells. Conversely, type 2 immunity involving group 2 innate lymphoid cells (ILC2s) and Th2 cells are involved in tissue regeneration and wound repair and are traditionally thought to have pro-tumoural effects. However, it is found that the classical type 2 immune cytokines IL-4, IL-5, IL-9, and IL-13 may have conflicting roles in cancer. Similarly, type 2 immunity-related cytokines IL-25 and IL-33 with recently characterised roles in cancer may either promote or suppress tumorigenesis in a context-dependent manner. Furthermore, type 1 cytokines IFNγ and TNFα have also been found to have pro-tumoural effects under certain circumstances, further complicating the overall picture. Therefore, the dichotomy of type 1 and type 2 cytokines inhibiting and promoting tumours respectively is not concrete, and attempts of utilising these for cancer immunotherapy must take into account all available evidence. This review provides an overview summarising the current understanding of type 1 and type 2 cytokines in tumour immunity and discusses the prospects of harnessing these for immunotherapy in light of previous and ongoing clinical trials.

Investigating the spatial interaction of immune cells in colon cancer

The intricate network of interactions between cells and molecules in the tumor microenvironment creates a heterogeneous ecosystem. The proximity of the cells and molecules to their activators and inhibitors is essential in the progression of tumors. Here, we develop a system of partial differential equations coupled with linear elasticity to investigate the effects of spatial interactions on the tumor microenvironment. We observe interesting cell and cytokine distribution patterns, which are heavily affected by macrophages. We also see that cytotoxic T cells get recruited and suppressed at the site of macrophages. Moreover, we observe that anti-tumor macrophages reorganize the patterns in favor of a more spatially restricted cancer and necrotic core. Furthermore, the adjoint-based sensitivity analysis indicates that the most sensitive model's parameters are directly related to macrophages. The results emphasize the widely acknowledged effect of macrophages in controlling cancer cells population and spatially arranging cells in the tumor microenvironment.

Transdermal delivery of celecoxib and α-linolenic acid from microemulsion-incorporated dissolving microneedles for enhanced osteoarthritis therapy

Dissolving microneedles, the promising vehicles for transdermal delivery, are incapable of directly loading hydrophobic components that limit the application of transdermal drug delivery. Microemulsion holds great potential in the solubilisation of water-insoluble drugs but is limited by the high epidermal retention. In this study, we fabricated microemulsion-incorporated dissolving microneedles co-loading celecoxib and α-linolenic acid (Cel-MEs@MNs) for enhancing osteoarthritis (OA) therapy via synergistic anti-inflammation and potent transdermal delivery. Cel-MEs@MNs composed of celecoxib & α-linolenic acid-coloaded microemulsion (Cel-MEs) and hyaluronic acid-based microneedles (MNs) can be completely dissolved in 90 s with a particle size of ∼30 nm. Each microneedle array with a hardness exceeding 30 N contained 57.9 ± 2.5 μg of celecoxib and 442.5 ± 24.2 μg of α-linolenic acid. The 8 h-cumulative transdermal of celecoxib from Cel-MEs@MNs was 89.2 ± 5.1 μg celecoxib/cm², which is 2.98-fold higher than that from Cel-MEs. Combinational celecoxib and α-linolenic acid with a weight ratio of 1/5 can synergistically induce M1-like macrophage to M2 repolarization, reduce M1-like macrophages-resulted chondrocytes apoptosis, and lower serum prostaglandin E-2 (PGE-2). Notably, Cel-MEs@MNs amplified such collaborated anti-inflammatory effects. More importantly, in the treatment of OA-bearing rat models, Cel-MEs@MNs with a half-dose of celecoxib and α-linolenic acid significantly shrunk the paw swelling, reduced inflammatory cytokines, and improved cartilage damage compared with the oral administration of celecoxib and α-linolenic acid, as well as transdermal administration of Cel-MEs. Such an integrational strategy of microemulsion-incorporated dissolving MNs offers the feasibility of combinational celecoxib and α-linolenic acid in transdermal permeation and boosted OA therapy.

Selective COX-2 Inhibitor Etoricoxib's Liposomal Formulation Attenuates M2 Polarization of TAMs and Enhances its Anti-metastatic Potential

INTRODUCTION

COX-2 inhibition in pro-tumoral M2 polarization of Tumor-Associated Macrophages (TAMs) underscore the improved prognosis and response to cancer therapy. Thus, etoricoxib, a COX-2 inhibiting NSAID drug is highly effective against tumorigenesis, but its compromised solubility and associated hepatotoxicity, and cardiotoxicity limit its clinical translation.

OBJECTIVE

In view of the consequences, the proposed study entails the development of a liposomal formulation for etoricoxib and evaluates its anticancer potential.

METHODS AND RESULT

Etoricoxib loaded liposome was prepared by thin layer hydration method and characterized as a nearly monodisperse system with particle size (91.64 nm), zeta potential (-44.5 mV), drug loading (17.22%), and entrapment efficiency (94.76%). The developed formulation was administered subcutaneously into the orthotopic 4T1/Balb/c mice model. Its treatment significantly reduced tumor size and skewed M2 polarization of TAMs to a greater extent against free etoricoxib. Furthermore, Tumor tissues analyzed through immunoblotting study confirmed the reduction in Akt phosphorylation at Thr308 residue and pro-tumoral VEGF, MMP-9, and MMP-2 proteins; Moreover, histology studies and microCT analysis of bones revealed the enhanced anti-metastatic potential of etoricoxib delivered through developed formulation against free etoricoxib.

CONCLUSION

As an epilogue, the developed formulation efficiently delivers poorly soluble etoricoxib, enhances its therapeutic potential as an anti-tumor and anti-metastatic agent, and directs explorative research for clinical translation.

Cyclooxygenase-2-Prostaglandin E2 pathway: A key player in tumor-associated immune cells

Cyclooxygenases-2 (COX-2) and Prostaglandin E2 (PGE2), which are important in chronic inflammatory diseases, can increase tumor incidence and promote tumor growth and metastasis. PGE2 binds to various prostaglandin E receptors to activate specific downstream signaling pathways such as PKA pathway, β-catenin pathway, NF-κB pathway and PI3K/AKT pathway, all of which play important roles in biological and pathological behavior. Nonsteroidal anti-inflammatory drugs (NSAIDs), which play as COX-2 inhibitors, and EP antagonists are important in anti-tumor immune evasion. The COX-2-PGE2 pathway promotes tumor immune evasion by regulating myeloid-derived suppressor cells, lymphocytes (CD8⁺ T cells, CD4⁺ T cells and natural killer cells), and antigen presenting cells (macrophages and dendritic cells). Based on conventional treatment, the addition of COX-2 inhibitors or EP antagonists may enhance immunotherapy response in anti-tumor immune escape. However, there are still a lot of challenges in cancer immunotherapy. In this review, we focus on how the COX-2-PGE2 pathway affects tumor-associated immune cells.

Effect of NETs/COX-2 pathway on immune microenvironment and metastasis in gastric cancer

Background

Neutrophil extracellular traps (NETs) are crucial in the progression of several cancers. The formation of NETs is closely related to reactive oxygen species (ROS), and the granule proteins involved in nucleosome depolymerization under the action of ROS together with the loosened DNA compose the basic structure of NETs. This study aims to investigate the specific mechanisms of NETs promoting gastric cancer metastasis in order to perfect the existing immunotherapy strategies.

Methods

In this study, the cells and tumor tissues of gastric cancer were detected by immunological experiments, real-time polymerase chain reaction and cytology experiments. Besides, bioinformatics analysis was used to analyze the correlation between cyclooxygenase-2 (COX-2) and the immune microenvironment of gastric cancer, as well as its effect on immunotherapy.

Results

Examination of clinical specimens showed that NETs were deposited in tumor tissues of patients with gastric cancer and their expression was significantly correlated with tumor staging. Bioinformatics analysis showed that COX-2 was involved in gastric cancer progression and was associated with immune cell infiltration as well as immunotherapy. In vitro experiments, we demonstrated that NETs could activate COX-2 through Toll-like receptor 2 (TLR2) and thus enhance the metastatic ability of gastric cancer cells. In addition, in a liver metastasis model of nude mice we also demonstrated the critical role of NETs and COX-2 in the distant metastasis of gastric cancer.

Conclusion

NETs can promote gastric cancer metastasis by initiating COX-2 through TLR2, and COX-2 may become a target for gastric cancer immunotherapy.

Antitumor Therapy Targeting the Tumor Microenvironment

The development and progression of tumors in human tissues extensively rely on its surrounding environment, that is, tumor microenvironment which includes a variety of cells, molecules, and blood vessels. These components are modified, organized, and integrated to support and facilitate the growth, invasion, and metabolism of tumor cells, suggesting them as potential therapeutic targets in anticancer treatment. An increasing number of pharmacological agents have been developed and clinically applied to target the oncogenic components in the tumor microenvironment, and in this review, we will summarize these pharmacological agents that directly or indirectly target the cellular or molecular components in the tumor microenvironment. However, difficulties and challenges still exist in this field, which will also be reported in this literature.

Crosstalk between epithelium, myeloid and innate lymphoid cells during gut homeostasis and disease

The gut epithelium not only provides a physical barrier to separate a noxious outside from a sterile inside but also allows for highly regulated interactions between bacteria and their products, and components of the immune system. Homeostatic maintenance of an intact epithelial barrier is paramount to health, requiring an intricately regulated and highly adaptive response of various cells of the immune system. Prolonged homeostatic imbalance can result in chronic inflammation, tumorigenesis and inefficient antitumor immune control. Here we provide an update on the role of innate lymphoid cells, macrophages and dendritic cells, which collectively play a critical role in epithelial barrier maintenance and provide an important linkage between the classical innate and adaptive arm of the immune system. These interactions modify the capacity of the gut epithelium to undergo continuous renewal, safeguard against tumor formation and provide feedback to the gut microbiome, which acts as a seminal contributor to cellular homeostasis of the gut.

The implications from the interplay of neoadjuvant chemoradiotherapy and the immune microenvironment in rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) is recommended for the treatment of locally advanced rectal cancer. Even though the combination of nCRT and immune checkpoint inhibitors (ICIs) has received much attention, the specific combination modes and dose fractions in radiotherapy (RT) are still indistinct. This review focuses on the immunological mechanism involved in nCRT, the clinical efficacy, the immunological effect of different combined strategies, concurrent or sequential nCRT plus ICIs, long-course RT and short-course RT. This review discusses the impact of nCRT on tumor immunity and summarizes the availability of different dose fractions in RT and distinct combined strategies, aiming at providing clues for optimal neoadjuvant therapy options that maximize efficacy and minimize side effects.

An innate IL-25-ILC2-MDSC axis creates a cancer-permissive microenvironment for Apc mutation-driven intestinal tumorigenesis

Interleukin-25 (IL-25) and group 2 innate lymphoid cells (ILC2s) defend the host against intestinal helminth infection and are associated with inappropriate allergic reactions. IL-33-activated ILC2s were previously found to augment protective tissue-specific pancreatic cancer immunity. Here, we showed that intestinal IL-25-activated ILC2s created an innate cancer-permissive microenvironment. Colorectal cancer (CRC) patients with higher tumor IL25 expression had reduced survival and increased IL-25R-expressing tumor-resident ILC2s and myeloid-derived suppressor cells (MDSCs) associated with impaired antitumor responses. Ablation of IL-25 signaling reduced tumors, virtually doubling life expectancy in an Apc mutation-driven model of spontaneous intestinal tumorigenesis. Mechanistically, IL-25 promoted intratumoral ILC2s, which sustained tumor-infiltrating MDSCs to suppress antitumor immunity. Therapeutic antibody-mediated blockade of IL-25 signaling decreased intratumoral ILC2s, MDSCs, and adenoma/adenocarcinoma while increasing antitumor adaptive T cell and interferon-γ (IFN-γ)-mediated immunity. Thus, the roles of innate epithelium-derived cytokines IL-25 and IL-33 as well as ILC2s in cancer cannot be generalized. The protumoral nature of the IL-25-ILC2 axis in CRC highlights this pathway as a potential therapeutic target against CRC.

Reprogramming the tumor microenvironment by genome editing for precision cancer therapy

The tumor microenvironment (TME) is essential for immune escape by tumor cells. It plays essential roles in tumor development and metastasis. The clinical outcomes of tumors are often closely related to individual differences in the patient TME. Therefore, reprogramming TME cells and their intercellular communication is an attractive and promising strategy for cancer therapy. TME cells consist of immune and nonimmune cells. These cells need to be manipulated precisely and safely to improve cancer therapy. Furthermore, it is encouraging that this field has rapidly developed in recent years with the advent and development of gene editing technologies. In this review, we briefly introduce gene editing technologies and systematically summarize their applications in the TME for precision cancer therapy, including the reprogramming of TME cells and their intercellular communication. TME cell reprogramming can regulate cell differentiation, proliferation, and function. Moreover, reprogramming the intercellular communication of TME cells can optimize immune infiltration and the specific recognition of tumor cells by immune cells. Thus, gene editing will pave the way for further breakthroughs in precision cancer therapy.

Design of Dual COX-2 and 5-LOX Inhibitors with Iron-Chelating Properties Using Structure-Based and Ligand-Based Methods

Background:

Inflammation is a critical component of many disease progressions, such as malignancy, cardiovascular and rheumatic diseases. The inhibition of inflammatory mediators synthesis by modulation of cyclooxygenase (COX) and lipoxygenase (LOX) pathways provides challenging strategy for development of more effective drugs.

Objective:

The aim of this study was to design dual COX-2 and 5-LOX inhibitors with iron-chelating properties using a combination of ligand-based (three-dimensional quantitative structure-activity relationship (3D-QSAR)) and structure-based (molecular docking) methods.

Methods:

The 3D-QSAR analysis was applied on a literature dataset consisting of 28 dual COX-2 and 5- LOX inhibitors in Pentacle software. The quality of developed COX-2 and 5-LOX 3D-QSAR models were evaluated by internal and external validation methods. The molecular docking analysis was performed in GOLD software, while selected ADMET properties were predicted in ADMET predictor software.

Results:

According to the molecular docking studies, the class of sulfohydroxamic acid analogues, previously designed by 3D-QSAR, were clustered as potential dual COX-2 and 5-LOX inhibitors with ironchelating properties. Based on the 3D-QSAR and molecular docking, 1j, 1g and 1l were selected as the most promising dual COX-2 and 5-LOX inhibitors. According to the in silico ADMET predictions, all compounds had ADMET_Risk score less than 7 and CYP_Risk score lower than 2.5. Designed compounds were not estimated as hERG inhibitors and 1j had improved intrinsic solubility (8.704) in comparison to the dataset compounds (0.411-7.946).

Conclusion:

By combining 3D-QSAR and molecular docking, three compounds (1j, 1g and 1l) were selected as the most promising designed dual COX-2 and 5-LOX inhibitors, for which good activity, as well as favourable ADMET properties and toxicity, are expected.

The COX-2-PGE2 pathway promotes tumor evasion in colorectal adenomas

The mechanisms underlying the regulation of a checkpoint receptor, PD-1, in tumor-infiltrating immune cells during the development of colorectal cancer (CRC) are not fully understood. Here we demonstrate that COX-2-derived PGE2, an inflammatory mediator and tumor promoter, induces PD-1 expression by enhancing NF-κB's binding to the PD-1 promoter via an EP4-PI3K-Akt signaling pathway in both CD8+ T cells and macrophages. Moreover, PGE2 suppresses CD8+ T cell proliferation and cytotoxicity against tumor cells and impairs macrophage phagocytosis of cancer cells via an EP4-PI3K-Akt-NF-κB-PD-1 signaling pathway. In contrast, inhibiting the COX-2-PGE2-EP4 pathway increases intestinal CD8+ T cell activation and proliferation and enhances intestinal macrophage phagocytosis of carcinoma cells accompanied by reduction of PD-1 expression in intestinal CD8+ T cells and macrophages in ApcMin/+ mice. PD-1 expression correlates well with COX-2 levels in human CRC specimens. Both elevated PD-1 and COX-2 are associated with poorer overall survival in colorectal cancer patients. Our results uncover a novel role of PGE2 in tumor immune evasion. They may provide the rationale for developing new therapeutic approaches to subvert this process by targeting immune checkpoint pathways using EP4 antagonists. In addition, our findings reveal a novel mechanism explaining how NSAIDs reduce colorectal cancer risk by suppressing tumor immune evasion.

Innate Immunity and Cancer Pathophysiology

Chronic inflammation increases the risk of several cancers, including gastric, colon, and hepatic cancers. Conversely, tumors, similar to tissue injury, trigger an inflammatory response coordinated by the innate immune system. Cellular and molecular mediators of inflammation modulate tumor growth directly and by influencing the adaptive immune response. Depending on the balance of immune cell types and signals within the tumor microenvironment, inflammation can support or restrain the tumor. Adding to the complexity, research from the past two decades has revealed that innate immune cells are highly heterogeneous and plastic, with variable phenotypes depending on tumor type, stage, and treatment. The field is now on the cusp of being able to harness this wealth of data to (a) classify tumors on the basis of their immune makeup, with implications for prognosis, treatment choice, and clinical outcome, and (b) design therapeutic strategies that activate antitumor immune responses by targeting innate immune cells.

Macrophage COX2 Mediates Efferocytosis, Resolution Reprogramming, and Intestinal Epithelial Repair

BACKGROUND AND AIMS

Phagocytosis (efferocytosis) of apoptotic neutrophils by macrophages anchors the resolution of intestinal inflammation. Efferocytosis prevents secondary necrosis and inhibits further inflammation, and also reprograms macrophages to facilitate tissue repair and promote resolution function. Macrophage efferocytosis and efferocytosis-dependent reprogramming are implicated in the pathogenesis of inflammatory bowel disease. We previously reported that absence of macrophage cyclooxygenase 2 (COX2) exacerbates inflammatory bowel disease-like intestinal inflammation. To elucidate the underlying pathogenic mechanism, we investigated here whether COX2 mediates macrophage efferocytosis and efferocytosis-dependent reprogramming, including intestinal epithelial repair capacity.

METHODS

Using apoptotic neutrophils and synthetic apoptotic targets, we determined the effects of macrophage specific Cox2 knockout and pharmacological COX2 inhibition on the efferocytosis capacity of mouse primary macrophages. COX2-mediated efferocytosis-dependent eicosanoid lipidomics was determined by liquid chromatography tandem mass spectrometry. Small intestinal epithelial organoids were employed to assay the effects of COX2 on efferocytosis-dependent intestinal epithelial repair.

RESULTS

Loss of COX2 impaired efferocytosis in mouse primary macrophages, in part, by affecting the binding capacity of macrophages for apoptotic cells. This effect was comparable to that of high-dose lipopolysaccharide and was accompanied by both dysregulation of macrophage polarization and the inhibited expression of genes involved in apoptotic cell binding. COX2 modulated the production of efferocytosis-dependent lipid inflammatory mediators that include the eicosanoids prostaglandin I2, prostaglandin E2, lipoxin A4, and 15d-PGJ2; and further affected secondary efferocytosis. Finally, macrophage efferocytosis induced, in a macrophage COX2-dependent manner, a tissue restitution and repair phenotype in intestinal epithelial organoids.

CONCLUSIONS

Macrophage COX2 potentiates efferocytosis capacity and efferocytosis-dependent reprogramming, facilitating macrophage intestinal epithelial repair capacity.

Cyclooxygenases and Prostaglandins in Tumor Immunology and Microenvironment of Gastrointestinal Cancer

Chronic inflammation is a known risk factor for gastrointestinal cancer. The evidence that nonsteroidal anti-inflammatory drugs suppress the incidence, growth, and metastasis of gastrointestinal cancer supports the concept that a nonsteroidal anti-inflammatory drug target, cyclooxygenase, and its downstream bioactive lipid products may provide one of the links between inflammation and cancer. Preclinical studies have demonstrated that the cyclooxygenase-2-prostaglandin E₂ pathway can promote gastrointestinal cancer development. Although the role of this pathway in cancer has been investigated extensively for 2 decades, only recent studies have described its effects on host defenses against transformed epithelial cells. Overcoming tumor-immune evasion remains one of the major challenges in cancer immunotherapy. This review summarizes the impacts of the cyclooxygenase-2-prostaglandin E₂ pathway on gastrointestinal cancer development. Our focus was to highlight recent advances in our understanding of how this pathway induces tumor immune evasion.

Tumour Microenvironment Stress Promotes the Development of Drug Resistance

Multi-drug resistance (MDR) is a leading cause of cancer-related death, and it continues to be a major barrier to cancer treatment. The tumour microenvironment (TME) has proven to play an essential role in not only cancer progression and metastasis, but also the development of resistance to chemotherapy. Despite the significant advances in the efficacy of anti-cancer therapies, the development of drug resistance remains a major impediment to therapeutic success. This review highlights the interplay between various factors within the TME that collectively initiate or propagate MDR. The key TME-mediated mechanisms of MDR regulation that will be discussed herein include (1) altered metabolic processing and the reactive oxygen species (ROS)-hypoxia inducible factor (HIF) axis; (2) changes in stromal cells; (3) increased cancer cell survival via autophagy and failure of apoptosis; (4) altered drug delivery, uptake, or efflux and (5) the induction of a cancer stem cell (CSC) phenotype. The review also discusses thought-provoking ideas that may assist in overcoming the TME-induced MDR. We conclude that stressors from the TME and exposure to chemotherapeutic agents are strongly linked to the development of MDR in cancer cells. Therefore, there remains a vast area for potential research to further elicit the interplay between factors existing both within and outside the TME. Elucidating the mechanisms within this network is essential for developing new therapeutic strategies that are less prone to failure due to the development of resistance in cancer cells.

Normalization of the tumor microvasculature based on targeting and modulation of the tumor microenvironment

Angiogenesis is an essential process for tumor development. Owing to the imbalance between pro- and anti-angiogenic factors, the tumor vasculature possesses the characteristics of tortuous, hyperpermeable vessels and compressive force, resulting in a reduction in the effect of traditional chemotherapy and radiotherapy. Anti-angiogenesis has emerged as a promising strategy for cancer treatment. Tumor angiogenesis, however, has been proved to be a complex process in which the tumor microenvironment (TME) plays a vital role in the initiation and development of the tumor microvasculature. The host stromal cells in the TME, such as cancer associated fibroblasts (CAFs), tumor associated macrophages (TAMs) and Treg cells, contribute to angiogenesis. Furthermore, the abnormal metabolic environment, such as hypoxia and acidosis, leads to the up-regulated expression of angiogenic factors. Indeed, normalization of the tumor microvasculature via targeting and modulating the TME has become a promising strategy for anti-angiogenesis and anti-tumor therapy. In this review, we summarize the abnormalities of the tumor microvasculature, tumor angiogenesis induced by an abnormal metabolic environment and host stromal cells, as well as drug delivery therapies to restore the balance between pro- and anti-angiogenic factors by targeting and normalizing the tumor vasculature in the TME.

Bringing Macrophages to the Frontline against Cancer: Current Immunotherapies Targeting Macrophages

Macrophages are found in all tissues and display outstanding functional diversity. From embryo to birth and throughout adult life, they play critical roles in development, homeostasis, tissue repair, immunity, and, importantly, in the control of cancer growth. In this review, we will briefly detail the multi-functional, protumoral, and antitumoral roles of macrophages in the tumor microenvironment. Our objective is to focus on the ever-growing therapeutic opportunities, with promising preclinical and clinical results developed in recent years, to modulate the contribution of macrophages in oncologic diseases. While the majority of cancer immunotherapies target T cells, we believe that macrophages have a promising therapeutic potential as tumoricidal effectors and in mobilizing their surroundings towards antitumor immunity to efficiently limit cancer progression.

Immunomodulation and Biomaterials: Key Players to Repair Volumetric Muscle Loss

Volumetric muscle loss (VML) is defined as a condition in which a large volume of skeletal muscle is lost due to physical insult. VML often results in a heightened immune response, resulting in significant long-term functional impairment. Estimates indicate that ~250,000 fractures occur in the US alone that involve VML. Currently, there is no active treatment to fully recover or repair muscle loss in VML patients. The health economics burden due to VML is rapidly increasing around the world. Immunologists, developmental biologists, and muscle pathophysiologists are exploring both immune responses and biomaterials to meet this challenging situation. The inflammatory response in muscle injury involves a non-specific inflammatory response at the injured site that is coordination between the immune system, especially macrophages and muscle. The potential role of biomaterials in the regenerative process of skeletal muscle injury is currently an important topic. To this end, cell therapy holds great promise for the regeneration of damaged muscle following VML. However, the delivery of cells into the injured muscle site poses a major challenge as it might cause an adverse immune response or inflammation. To overcome this obstacle, in recent years various biomaterials with diverse physical and chemical nature have been developed and verified for the treatment of various muscle injuries. These biomaterials, with desired tunable physicochemical properties, can be used in combination with stem cells and growth factors to repair VML. In the current review, we focus on how various immune cells, in conjunction with biomaterials, can be used to promote muscle regeneration and, most importantly, suppress VML pathology.

New Angiogenic Regulators Produced by TAMs: Perspective for Targeting Tumor Angiogenesis

Simple Summary

Since the targeting of a single pro-angiogenic factor fails to improve oncological disease outcome, significant efforts have been made to identify new pro-angiogenic factors that could compensate for the deficiency of current therapy or act independently as single drugs. Our review aims to present the state-of-the art for well-known and recently described factors produced by macrophages that induce and regulate angiogenesis. A number of positive and negative regulators of angiogenesis in the tumor microenvironment are produced by tumor-associated macrophages (TAMs). Accumulating evidence has indicated that, apart from the well-known angiogenic factors, there are plenty of novel angiogenesis-regulating proteins that belong to different classes. We summarize the data regarding the direct or indirect mechanisms of the interaction of these factors with endothelial cells during angiogenesis. We highlight the recent findings that explain the limitations in the efficiency of current anti-angiogenic therapy approaches.

Abstract

Angiogenesis is crucial to the supply of a growing tumor with nutrition and oxygen. Inhibition of angiogenesis is one of the main treatment strategies for colorectal, lung, breast, renal, and other solid cancers. However, currently applied drugs that target VEGF or receptor tyrosine kinases have limited efficiency, which raises a question concerning the mechanism of patient resistance to the already developed drugs. Tumor-associated macrophages (TAMs) were identified in the animal tumor models as a key inducer of the angiogenic switch. TAMs represent a potent source not only for VEGF, but also for a number of other pro-angiogenic factors. Our review provides information about the activity of secreted regulators of angiogenesis produced by TAMs. They include members of SEMA and S100A families, chitinase-like proteins, osteopontin, and SPARC. The COX-2, Tie2, and other factors that control the pro-angiogenic activity of TAMs are also discussed. We highlight how these recent findings explain the limitations in the efficiency of current anti-angiogenic therapy. Additionally, we describe genetic and posttranscriptional mechanisms that control the expression of factors regulating angiogenesis. Finally, we present prospects for the complex targeting of the pro-angiogenic activity of TAMs.

Preferential Expression of Programmed Death Ligand 1 Protein in Tumor-Associated Macrophages and Its Potential Role in Immunotherapy for Hepatocellular Carcinoma

A predictive biomarker of immune checkpoint inhibitor (ICI)-based treatments in hepatocellular carcinoma (HCC) has not been clearly demonstrated. In this study, we focused on the infiltration and programmed death ligand 1 (PD-L1) expression of tumor-associated macrophages (TAMs) in the tumor microenvironment of HCC. Immunohistochemistry demonstrated that PD-L1 was preferentially expressed on CD68+ macrophages in the tumor microenvironment of HCC, suggestive of its expression in TAMs rather than in T cells or tumor cells (P < 0.05). A co-culture experiment using activated T cells and M2 macrophages confirmed a significant increase in T cell functionality after the pretreatment of M2 macrophages with anti-PD-L1. Syngeneic mouse model experiments demonstrated that TAMs expressed PD-L1 and tumors treated with anti-PD-L1 showed smaller diameters than those treated with IgG. In these mice, anti-PD-L1 treatment increased activation markers in intratumoral CD8+ T cells and reduced the size of the TAM population. Regarding nivolumab-treated patients, three of eight patients responded to the anti-PD-1 treatment. The percentage of Ki-67-positive CD4+ and CD8+ T cells was higher in responders than non-responders after nivolumab. Overall, PD-L1 expression on TAMs may be targeted by immune-based HCC treatment, and ICI treatment results in the reinvigoration of exhausted CD8+ T cells in HCC.

Immune Microenvironment: New Insight for Familial Adenomatous Polyposis

Currently, the main treatment for familial adenomatous polyposis (FAP) is surgery, however, surgery is far from ideal as there are many complications such as uncontrollable bowel movements, pouch inflammation, anastomotic stricture, and secondary fibroids. Therefore, it is necessary to further expand the understanding of FAP and develop new treatments for FAP. The immune microenvironment including immune cells and cytokines, plays an important role in FAP and the progression of FAP to adenocarcinoma, thus it may be a promising treatment for FAP. In the current review, we summarized the recent progress in the immune microenvironment of FAP.

Macrophage reprogramming for therapy

Dysfunction of the immune system underlies a plethora of human diseases, requiring the development of immunomodulatory therapeutic intervention. To date, most strategies employed have been focusing on the modification of T lymphocytes, and although remarkable improvement has been obtained, results often fall short of the intended outcome. Recent cutting-edge technologies have highlighted macrophages as potential targets for disease control. Macrophages play central roles in development, homeostasis and host defence, and their dysfunction and dysregulation have been implicated in the onset and pathogenesis of multiple disorders including cancer, neurodegeneration, autoimmunity and metabolic diseases. Recent advancements have led to a greater understanding of macrophage origin, diversity and function, in both health and disease. Over the last few years, a variety of strategies targeting macrophages have been developed and these open new therapeutic opportunities. Here, we review the progress in macrophage reprogramming in various disorders and discuss the potential implications and challenges for macrophage-targeted approaches in human disease.

The role of macrophage in regulating tumour microenvironment and the strategies for reprogramming tumour-associated macrophages in antitumour therapy

Tumour-associated macrophages (TAMs) that present abundantly in the tumour microenvironment (TME) exhibit a protumour property, such as promoting genetic instability, tumour metastasis and immunosuppression. Macrophage-targeted therapeutic approaches hence have been applied and shown their significances in the process of tumour immune treatment, including blocking TAM recruitment, depleting or transforming TAMs that already exist in the tumour site. Here, we summarized the functional regulation of TAMs in the respects of hypoxia environment, metabolism in the tumour microenvironment and the transcription factors involved. We reviewed the strategies for transforming TAMs, including immune stimuli targeting TAMs, inhibitors against TAMs, pathogen or irradiation stimulation on TAMs, and the application of natural compounds in TAMs. Furthermore, we also discussed the macrophage-targeted therapies in the clinical studies. Taken together, this review tries to shed light on the TAM regulation and the main strategies of TAM reprogramming for an enhanced immune surveillance.

An Overview of Advances in Cell-Based Cancer Immunotherapies Based on the Multiple Immune-Cancer Cell Interactions

Tumors have a complex ecosystem in which behavior and fate are determined by the interaction of diverse cancerous and noncancerous cells at local and systemic levels. A number of studies indicate that various immune cells participate in tumor development (Fig. 1). In this review, we will discuss interactions among T lymphocytes (T cells), B cells, natural killer (NK) cells, dendritic cells (DCs), tumor-associated macrophages (TAMs), neutrophils, and myeloid-derived suppressor cells (MDSCs). In addition, we will touch upon attempts to either use or block subsets of immune cells to target cancer.

New insights into molecular pathways in colorectal cancer: Adiponectin, interleukin-6 and opioid signaling

Colorectal cancer (CRC) is one of the most common cause of death among neoplasms around the world. The environmental factors, like diet and obesity, are crucial in CRC pathogenesis by creating cancer-favorable microenvironment and hormonal changes. Adiponectin, the adipose tissue-specific hormone, is generally considered to negatively correlate with CRC development. The interleukin 6 (IL-6) is one of the most important pro-inflammatory cytokine connected with CRC, which is strongly inflammation-associated. The opioids are variable group substantially correlated with cancers - the endogenous opioids affect immune system and cell cycle including proliferation and cell death whereas exogenous opioids are leading clinically used analgesics in terminal cancer patients. In this review we discuss the involvement of adiponectin, IL-6 and opioids in CRC pathogenesis, their link with obesity, possible cross-talk and potential novel therapeutic approach in CRC treatment.

Targeting Lipid Metabolism in Liver Cancer

Cancer cells are highly dependent on different metabolic pathways for sustaining their survival, growth, and proliferation. Lipid metabolism not only provides the energetic needs of the cells but also provides the raw material for cellular growth and the signaling molecules for many oncogenic pathways. Mainly processed in the liver, lipids play an essential role in the physiology of this organ and in the pathological progression of many diseases such as metabolic syndrome and hepatocellular carcinoma (HCC). The progression of HCC is associated with inflammation and complex metabolic reprogramming, and its prognosis remains poor because of the lack of effective therapies despite many years of dedicated research. Defects in hepatic lipid metabolism induce abnormal gene expression and rewire many cellular pathways involved in oncogenesis and metastasis, implying that interfering with lipid metabolism within the tumor and the surrounding microenvironment may be a novel therapeutic approach for treating liver cancer patients. Therefore, this review focuses on the latest advances in drugs targeting lipid metabolism and leading to promising outcomes in preclinical studies and some ongoing clinical trials.

At the Forefront of the Mucosal Barrier: The Role of Macrophages in the Intestine

Macrophages are part of the innate immunity and are key players for the maintenance of intestinal homeostasis. They belong to the group of mononuclear phagocytes, which exert bactericidal functions and help to clear apoptotic cells. Moreover, they play essential roles for the maintenance of epithelial integrity and tissue remodeling during wound healing processes and might be implicated in intestinal tumor development. Macrophages are antigen-presenting cells and secrete immune-modulatory factors, like chemokines and cytokines, which are necessary to activate other intestinal immune cells and therefore to shape immune responses in the gut. However, overwhelming activation or increased secretion of pro-inflammatory cytokines might also contribute to the pathogenesis of inflammatory bowel disease. Presently, intestinal macrophages are in the center of intense studies, which might help to develop new therapeutic strategies to counteract the development or treat already existing inflammatory diseases in the gut. In this review, we focus on the origin of intestinal macrophages and, based on current knowledge, discuss their role in the gut during homeostasis and inflammation, as well as during intestinal wound healing and tumor development.

Overcoming resistance to STING agonist therapy to incite durable protective antitumor immunity

BACKGROUND

Activating the Stimulator of Interferon Genes (STING) adaptor incites antitumor immunity against immunogenic tumors in mice, prompting clinical trials to test STING activators. However, STING signaling in the tumor microenvironment (TME) during development of Lewis lung carcinoma (LLC) suppresses antitumor immunity to promote tumor growth. We hypothesized that local immune balance favoring suppression of antitumor immunity also attenuates antitumor responses following STING activation. The purpose of this study was to evaluate how STING activation impacts antitumor responses in mice bearing LLC tumors.

METHODS

Mice bearing established LLC tumors were treated with synthetic cyclic diadenyl monophosphate (CDA) to activate STING. Mice were monitored to assess LLC tumor growth, survival and protective antitumor immunity. Transcriptional and metabolic analyses were used to identify pathways responsive to CDA, and mice were co-treated with CDA and drugs that disrupt these pathways.

RESULTS

CDA slowed LLC tumor growth but most CDA-treated mice (77%) succumbed to tumor growth. No evidence of tumor relapse was found in surviving CDA-treated mice at experimental end points but mice were not immune to LLC challenge. CDA induced rapid increase in immune regulatory pathways involving programmed death-1 (PD-1), indoleamine 2,3 dioxygenase (IDO) and cyclooxygenase-2 (COX2) in the TME. PD-1 blockade enhanced antitumor responses to CDA and increased mouse survival but mice did not eliminate primary tumor burdens. Two IDO inhibitor drugs had little or no beneficial effects on antitumor responses to CDA. A third IDO inhibitor drug synergized with CDA to enhance tumor control and survival but mice did not eliminate primary tumor burdens. In contrast, co-treatments with CDA and the COX2-selective inhibitor celecoxib controlled tumor growth, leading to uniform survival without relapse, and mice acquired resistance to LLC re-challenge and growth of distal tumors not exposed directly to CDA. Thus, mice co-treated with CDA and celecoxib acquired stable and systemic antitumor immunity.

CONCLUSIONS

STING activation incites potent antitumor responses and boosts local immune regulation to attenuate antitumor responses. Blocking STING-responsive regulatory pathways synergizes with CDA to enhance antitumor responses, particularly COX2 inhibition. Thus, therapy-induced resistance to STING may necessitate co-treatments to disrupt regulatory pathways responsive to STING in patients with cancer.

FDPS promotes glioma growth and macrophage recruitment by regulating CCL20 via Wnt/β-catenin signalling pathway

Glioma is one of the most lethal tumours and common malignant in the central nervous system (CNS), which exhibits diffuse invasion and aggressive growth. Several studies have reported the association of FDPS to tumour development and progression. However, the role of FDPS in progression of glioma and macrophage recruitment is not well‐elucidated. In the current study, a remarkable enhancement in FDPS level was observed in glioma tissues and associated with poor prognosis, contributed to tumour growth. FDPS was correlated with macrophage infiltration in glioma and pharmacological deletion of macrophages largely abrogated the oncogenic functions of FDPS in glioma. Mechanistically, FDPS activated Wnt/β‐catenin signalling pathway and ultimately facilitates macrophage infiltration by inducing CCL20 expression. In conclusion, overexpressed FDPS exhibits an immunomodulatory role in glioma. Therefore, targeting FDPS may be an effective therapeutic strategy for glioma.

EP4 signalling is essential for controlling islet inflammation by causing a shift in macrophage polarization in obesity/type 2 diabetes

Activation of the prostaglandin E₂ receptor EP4 alters polarization of adipose tissue macrophages towards the anti-inflammatory M2 phenotype to suppress chronic inflammation. However, the role of EP4 signalling in pancreatic macrophages that affect insulin secretion is unclear. We examined the role of EP4 signalling in islet inflammation in vitro and in vivo. Obese diabetic db/db mice were treated with an EP4-selective agonist or vehicle for 4 weeks. Islet morphology did not significantly differ and glucose-stimulated insulin secretion was increased, whereas the pancreatic M1/M2 ratio was decreased in the EP4 agonist-treated group compared to the vehicle group. Because EP4 activation in MIN6 cells did not affect insulin secretion, we used a MIN6/macrophage co-culture system to evaluate the role of EP4 signalling in islet inflammation and subsequent inhibition of insulin release. Co-culture with M1-polarized macrophages markedly suppressed insulin expression in MIN6 cells; however, modulation of M1 polarization by the EP4 agonist significantly reversed the negative impact of co-cultivation on insulin production. The enhanced expression levels of pro-inflammatory cytokines in co-cultured MIN6 cells were markedly inhibited by EP4 agonist treatment of M1 macrophages. Thus, EP4 activation may suppress islet inflammation and protect β-cell function by altering inflammatory macrophages in the diabetic pancreas.

Combined chemotherapy with cyclooxygenase-2 (COX-2) inhibitors in treating human cancers: Recent advancement

Chemotherapy with a single chemotherapeutic agent or a combined chemotherapeutic regimen is the clinically standardized treatment for almost all human cancers. Upregulated expression of cyclooxygenase (COX)-2, also known as prostaglandin-endoperoxide synthase (PTGS), is associated with human carcinogenesis and cancer progression and COX-2 inhibitors show antitumor activity in different human cancers. Thus, a combination of chemotherapeutic agents with COX-2 inhibitors has been shown to improve therapeutic effects on human cancers. This review discusses and summarizes recent advances in cancer control and treatment using various antineoplastic drugs combined with COX-2 inhibitors. These combinations showed synergistic antitumor effects. At the gene level, COX-2 inhibitors can reduce inflammatory factors thereby regulating macrophage recruitment for activating the antitumor immune microenvironment; downregulating vascular endothelial growth factor (VEGF) to inhibit tumor angiogenesis; and inhibiting the PI3K/Akt signaling pathway to induce tumor cell apoptosis. In addition, such a combination can reduce toxicity and chemoresistance and enhance radiosensitivity, although COX-2 inhibitors-related cardiotoxicity may potentially affect its use. Further in-depth investigation of these drug combinations is needed to maximize antitumor efficacy and minimize the side effects.

Inflammatory Responses during Tumour Initiation: From Zebrafish Transgenic Models of Cancer to Evidence from Mouse and Man

The zebrafish is now an important model organism for cancer biology studies and provides unique and complementary opportunities in comparison to the mammalian equivalent. The translucency of zebrafish has allowed in vivo live imaging studies of tumour initiation and progression at the cellular level, providing novel insights into our understanding of cancer. Here we summarise the available transgenic zebrafish tumour models and discuss what we have gleaned from them with respect to cancer inflammation. In particular, we focus on the host inflammatory response towards transformed cells during the pre-neoplastic stage of tumour development. We discuss features of tumour-associated macrophages and neutrophils in mammalian models and present evidence that supports the idea that these inflammatory cells promote early stage tumour development and progression. Direct live imaging of tumour initiation in zebrafish models has shown that the intrinsic inflammation induced by pre-neoplastic cells is tumour promoting. Signals mediating leukocyte recruitment to pre-neoplastic cells in zebrafish correspond to the signals that mediate leukocyte recruitment in mammalian tumours. The activation state of macrophages and neutrophils recruited to pre-neoplastic cells in zebrafish appears to be heterogenous, as seen in mammalian models, which provides an opportunity to study the plasticity of innate immune cells during tumour initiation. Although several potential mechanisms are described that might mediate the trophic function of innate immune cells during tumour initiation in zebrafish, there are several unknowns that are yet to be resolved. Rapid advancement of genetic tools and imaging technologies for zebrafish will facilitate research into the mechanisms that modulate leukocyte function during tumour initiation and identify targets for cancer prevention.

Immunogenic cell death in colon cancer prevention and therapy

Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide. The colonic mucosa constitutes a critical barrier and a major site of immune regulation. The immune system plays important roles in cancer development and treatment, and immune activation caused by chronic infection or inflammation is well-known to increase cancer risk. During tumor development, neoplastic cells continuously interact with and shape the tumor microenvironment (TME), which becomes progressively immunosuppressive. The clinical success of immune checkpoint blockade therapies is limited to a small set of CRCs with high tumor mutational load and tumor-infiltrating T cells. Induction of immunogenic cell death (ICD), a type of cell death eliciting an immune response, can therefore help break the immunosuppressive TME, engage the innate components, and prime T cell-mediated adaptive immunity for long-term tumor control. In this review, we discuss the current understanding of ICD induced by antineoplastic agents, the influence of driver mutations, and recent developments to harness ICD in colon cancer. Mechanism-guided combinations of ICD-inducing agents with immunotherapy and actionable biomarkers will likely offer more tailored and durable benefits to patients with colon cancer.

Cyclic adenosine monophosphate in acute ischemic stroke: some to update, more to explore

The development of effective treatment for ischemic stroke, which is a common cause of morbidity and mortality worldwide, remains an unmet goal because the current first-line treatment management interventional therapy has a strict time window and serious complications. In recent years, a growing body of evidence has shown that the elevation of intracellular and extracellular cyclic adenosine monophosphate (cAMP) alleviates brain damage after ischemic stroke by attenuating neuroinflammation in the central nervous system and peripheral immune system. In the central nervous system, upregulated intracellular cAMP signaling can alleviate immune-mediated damage by restoring neuronal morphology and function, inhibiting microglia migration and activation, stabilizing the membrane potential of astrocytes and improving the cellular functions of endothelial cells and oligodendrocytes. Enhancement of the extracellular cAMP signaling pathway can improve neurological function by activating the cAMP-adenosine pathway to reduce immune-mediated damage. In the peripheral immune system, cAMP can act on various immune cells to suppress peripheral immune function, which can alleviate the inflammatory response in the central nervous system and improve the prognosis of acute cerebral ischemic injury. Therefore, cAMP may play key roles in reducing post-stroke neuroinflammatory damage. The protective roles of the cAMP indicate that the cAMP enhancing drugs such as cAMP supplements, phosphodiesterase inhibitors, adenylate cyclase agonists, which are currently used in the treatment of heart and lung diseases. They are potentially able to be applied as a new therapeutic strategy in ischemic stroke. This review focuses on the immune-regulating roles and the clinical implication of cAMP in acute ischemic stroke.

Evaluation of Glycosylated PTGS2 in Colorectal Cancer for NSAIDS-Based Adjuvant Therapy

Observational/retrospective studies indicate that prostaglandin-endoperoxide synthase-2 (PTGS2) inhibitors could positively affect colorectal cancer (CRC) patients' survival after diagnosis. To obtain an acceptable cost/benefit balance, the inclusion of PTGS2 inhibitors in the adjuvant setting needs a selective criterion. We quantified the 72 kDa, CRC-associated, glycosylated form of PTGS2 in 100 frozen CRC specimens and evaluated PTGS2 localization by IHC in the same tumors, scoring tumor epithelial-derived and stroma-derived fractions. We also investigated the involvement of interleukin-1 beta (IL1β) in PTGS2 induction, both in vitro and in CRC lysates. Finally, we used overall survival (OS) as a criterion for patient selection. Glycosylated PTGS2 can be quantified with high sensibility in tissue lysates, but the expression in both tumor and stromal cells limits its use for predictive purposes. Immunohistochemistry (IHC) analysis indicates that stromal PTGS2 expression could exert a protective role on patient OS. Stromal PTGS2 was prevalently expressed by cancer-associated fibroblasts exerting a barrier function near the gut lumen, and it apparently favored the antitumor M1 macrophage population. IL1β was directly linked to gPTGS2 expression both in vitro and in tumors, but its activity was apparently prevalent on the stromal cell population. We suggest that stromal PTGS2 could exert a positive effect on patients OS when expressed in the luminal area of the tumor.