Research studies aimed at improving the outcomes of patients with pancreatic ductal adenocarcinoma (PDAC) have brought about limited progress, and in clinical practice, the optimized use of surgery, chemotherapy and supportive care have led to modest improvements in survival that have probably reached a plateau. As a result, PDAC is expected to be the second leading cause of cancer-related death in Western societies within a decade. The development of therapeutic advances in PDAC has been challenging owing to a lack of actionable molecular targets, a typically immunosuppressive microenvironment, and a disease course characterized by rapid progression and clinical deterioration. Yet, the progress in our understanding of PDAC and identification of novel therapeutic opportunities over the past few years is leading to a strong sense of optimism in the field. In this Perspective, we address the aforementioned challenges, including biological aspects of PDAC that make this malignancy particularly difficult to treat. We explore specific areas with potential for therapeutic advances, including targeting mutant KRAS, novel strategies to harness the antitumour immune response and approaches to early detection, and propose mechanisms to improve clinical trial design and to overcome various community and institutional barriers to progress.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by a dense extracellular matrix (ECM) and a uniquely immunosuppressive tumor microenvironment (TME), which together form a formidable barrier that hinders deep drug penetration, limiting the efficacy of conventional therapies and leading to poor patient outcomes. Nanocarrier technology emerges as a promising strategy to improve treatment efficacy in PDAC. Nanocarriers can not only improve drug penetration through their adjustable physicochemical properties but also effectively regulate immune cell function in pancreatic cancer TME and promote anti-tumor immune response. This mini-review discusses the effects of nanocarriers on the immune microenvironment of PDAC, analyzing their mechanisms in modulating immune cells, overcoming ECM barriers, and reshaping the TME.

Over the last decade, immune checkpoint inhibitors (ICIs) like PD-1/PD-L1 or CTLA-4, which reinvigorate T cells for tumor control have become standard-of-care treatment options. In response to the increasingly recognized mechanisms of resistance to T cell activation in immunologically cold tumors, immuno-oncology drug development has started to shift beyond T cell approaches. These include tumor-associated macrophages (TAMs), a major pro-tumor immune cell population in the tumor microenvironment known to silence immune responses.

Here we outline anti-TAM therapies in current development, either as monotherapy or in combination with other treatment modalities. We describe emerging drugs targeting TAMs under investigation in phase II and III testing with a focus on their distinguishing mechanism of action which include (1) reprogramming of TAMs toward anti-tumor function and immune surveillance, (2) blockade of recruitment, and (3) reduction and ablation of TAMs.

Several new immuno-oncology agents are under investigation to harness anti-tumor functions of TAMs. While robust anti-tumor efficacy of anti-TAM therapies across advanced solid organ cancers remains elusive to-date, TAM reprogramming therapies have yielded benefits in select cancers. The inherent heterogeneity of the diverse TAM population will require enhanced investments into biomarker-driven approaches to fully leverage its therapeutic potential.

T cells and their effector functions, in particular the canonical cytotoxicity of CD8+ T cells involving perforin, granzymes, Fas ligand (FasL), and tumor necrosis factor related apoptosis inducing ligand (TRAIL), are crucial for tumor immunity. Here, we reveal a previously unidentified mechanism by which CD40L-expressing CD8+ T cells induce cytotoxicity in cancer cells. In murine models, up to 50% of tumor-specific CD8+ T cells expressed CD40L, and conditional CD40L ablation in CD8+ T cells alone led to tumor formation. Mechanistically, CD40L+CD8+ T cells can induce cell death in CD40-expressing cancer cells by triggering caspase-8 activation. We demonstrate that a gene signature for resistance to CD40 signaling-induced cell death strongly correlates with worse survival in different human cancer cohorts. Our results introduce CD40L as a rather counterintuitive, noncanonical cytotoxic factor that complements the capabilities of CD8+ T cells to combat cancers and has the potential to enhance the efficacy of immunotherapies.

The tumor microenvironment (TME) plays a crucial role in cancer development and spreading being considered as "the dark side of the tumor". Within this term tumor cells, immune components, supporting cells, extracellular matrix and a myriad of bioactive molecules that synergistically promote tumor development and therapeutic resistance, are included. Recent findings revealed the profound impacts of TME on cancer development, serving as physical support, critical mediator and biodynamic matrix in cancer evolution, immune modulation, and treatment outcomes. TME targeting strategies built on vasculature, immune checkpoints, and immuno-cell therapies, have paved the way for revolutionary clinical interventions. On this basis, the relevance of pre-clinical and clinical investigations has rapidly become fundamental for implementing novel therapeutical strategies breaking cell-cell and cell -mediators' interactions between TME components and tumor cells. This review summarizes the key players in the breast and pancreatic TME, elucidating the intricate interactions among cancer cells and their essential role for cancer progression and therapeutic resistance. Different tumors such breast and pancreatic cancer have both different and similar stroma features, that might affect therapeutic strategies. Therefore, this review aims to comprehensively evaluate recent findings for refining breast and pancreatic cancer therapies and improve patient prognoses by exploiting the TME's complexity in the next future.

Macrophages play a critical role in various diseases, including cancer, where their involvement is characterized by a dual nature. There is a growing focus on tumor-associated macrophages (TAMs) in cancer research due to their complex interactions with tumor biology. With the expanding body of research in this area, a retrospective analysis of published articles is warranted to gain insights into evolving trends. This bibliometric study aims to assist researchers in identifying key areas of interest and emerging directions within the field of TAM research.

A bibliometric analysis was performed using the Bibliometrix Package in R Software and CiteSpace software.

The volume of research on TAMs continues to increase, with this study identifying major contributors to the field. The focus of research has shifted from traditional methods, such as flow cytometry and histological techniques, toward single-cell omics approaches, which offer unbiased insights into TAM heterogeneity. Current areas of interest include biomarkers, immune therapies, TAM states, tumor microenvironments, macrophage-targeted agents, and the response of TAMs to therapeutic interventions. These topics are anticipated to remain prominent in the near future.

The study provides an overview of annual publication trends, influential papers, key journals, frequently used keywords, leading authors, and contributing institutions. It also highlights the interdisciplinary evolution of TAM-related research and the connections between these areas of study.

Dysregulated cell movement is a hallmark of cancer progression and metastasis, the leading cause of cancer-related mortality. The metastatic cascade involves tumour cell migration, invasion, intravasation, dissemination, and colonisation of distant organs. These processes are influenced by reciprocal interactions between cancer cells and the tumour microenvironment (TME), including immune cells, stromal components, and extracellular matrix proteins. The epithelial-mesenchymal transition (EMT) plays a crucial role in providing cancer cells with invasive and stem-like properties, promoting dissemination and resistance to apoptosis. Conversely, the mesenchymal-epithelial transition (MET) facilitates metastatic colonisation and tumour re-initiation. Immune cells within the TME contribute to either anti-tumour response or immune evasion. These cells secrete cytokines, chemokines, and growth factors that shape the immune landscape and influence responses to immunotherapy. Notably, immune checkpoint blockade (ICB) has transformed cancer treatment, yet its efficacy is often dictated by the immune composition of the tumour site. Elucidating the molecular cross-talk between immune and cancer cells, identifying predictive biomarkers for ICB response, and developing strategies to convert cold tumours into immune-active environments is critical to overcoming resistance to immunotherapy and improving patient survival.

Many cancer patients develop resistance to immunotherapy, highlighting the urgent need for novel therapeutic strategies. Various factors contribute to tumor resistance to immunotherapy, among which tumor-associated macrophages (TAMs) are critical regulators of tumor sensitivity. Therefore, combining cancer immunotherapies with drug delivery systems (DDSs) targeting TAMs has become an intriguing treatment strategy. However, the target molecules used in DDSs are limited to a few receptors expressed on TAMs. Therefore, the identification of novel target molecules for TAM-specific DDS is urgently needed. The current study evaluated the ability of a cholesteryl pullulan (CHP) nanogel to target TAMs via mDC-SIGN (CD209b). This nanogel encapsulated the cytotoxic protein drug Pseudomonas exotoxin A and was injected into a tumor-bearing mouse model. This treatment significantly reduced the abundance of CD209b-positive M2 TAMs and enhanced antitumor immune responses. Ultimately, tumor growth was suppressed, even in a low-immunogenic tumor model. Hence, CD209b is an effective target molecule for M2 TAM-specific DDSs that can be used to develop novel cancer therapies.

Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive and fatal cancer. M1 macrophages are generally considered to have anti-tumor properties, capable of suppressing tumor growth and metastasis by secreting pro-inflammatory cytokines and enhancing the immune response.

The objective of this research was to pinpoint crucial genes associated with M1 macrophages and search for a new way to activate the M1 phenotype of macrophages in PDA.

The level of immune cell infiltration was assessed using CIBERSORT in TCGA-PAAD cohort and ICGC-PACA cohort. We performed weighted gene co-expression network analysis (WGCNA) to identify the module most correlated with M1 macrophages and we identified hub genes through protein-protein interaction (PPI) analyse. Through survival analysis, correlation analysis and single cell analysis, we obtained the relationship between hub genes and prognosis, and the relationship between key genes and immune cells, as well as its expression in various cells.

PRSS1 (Cationic trypsinogen) and CTRB1 (Chymosinogen B) were hub genes of the M1 macrophage-associated WGCNA module (211genes) and are closely related to the extension of survival time, which are also verified as cell growth-related genes by DepMap database. Through single-cell sequencing analysis, we determined that the expression levels of PRSS1 and CTRB1 in the acinar cells of tumor tissues were diminished. PRSS1 and CTRB1 are considered to be the signature genes of acinar cells. The proportion of acinar cells was also correlated with the infiltration of CD8T cells and M1 cells. Immunostaining revealed elevated expression levels of PRSS1 and CTRB1 in adjacent normal tissues. Cell line experiments confirmed that macrophages polarize towards M1 by engulfing pancreatic enzyme granules, thereby inhibiting the malignant phenotype of tumor cells.

Our findings highlight the critical role of acinar cells in modulating the immune microenvironment of pancreatic tumors by influencing macrophage polarization. This insight may provide novel opportunities for therapeutic interventions in cancer treatment.

Idiopathic inflammatory myopathies (IIMs) are heterogeneous autoimmune disorders characterized by muscle inflammation, weakness, and extramuscular manifestations such as interstitial lung disease, skin rash, arthritis, dysphagia, myocarditis and other systemic organ involvement. Although T and B cells have historically been central to the understanding of IIM immunopathology, monocytes and their differentiated progenitor cells, macrophages, are increasingly being recognized as critical mediators of both tissue damage and repair. In subtypes such as dermatomyositis, immune-mediated necrotizing myopathy and antisynthetase syndrome, macrophages infiltrate skeletal muscle and other affected tissues, contributing to inflammation via production of pro-inflammatory cytokines, chemokines, and reactive oxygen species. Dysregulated interferon signaling, mitochondrial stress, and aberrant metabolic states in these cells further perpetuate tissue injury in IIMs. Conversely, certain macrophage subsets can support muscle fiber regeneration and dampen inflammation, underscoring the dual roles these cells can play. Future research into the heterogeneity of monocytes and macrophages, including single-cell transcriptomic and metabolomic approaches, will help clarify disease mechanisms, identify biomarkers of disease activity and prognosis, and guide novel therapeutic strategies targeting these innate immune cells in IIM.

Genes that participate in the absorption, distribution, metabolism, excretion (ADME) processes occupy a central role in pharmacokinetics. Meanwhile, variability in clinical outcomes and responses to treatment is notable in bladder cancer (BLCA).

Our study utilized expansive datasets from TCGA and the GEO to explore prognostic factors in bladder cancer. Utilizing both univariate Cox regression and the lasso regression techniques, we identified ADME genes critical for patient outcomes. Utilizing genes identified in our study, a model for assessing risk was constructed. The evaluation of this model's predictive precision was conducted using Kaplan-Meier survival curves and assessments based on ROC curves. Furthermore, we devised a predictive nomogram, offering a straightforward visualization of crucial prognostic indicators. To explore the potential factors mediating the differences in outcomes between high and low risk groups, we performed comprehensive analyses including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG)-based enrichment analyses, immune infiltration variations, somatic mutation landscapes, and pharmacological sensitivity response assessment etc. Immediately following this, we selected core genes based on the PPI network and explored the prognostic potential of the core genes as well as immune modulation, and pathway activation. And the differential expression was verified by immunohistochemistry and qRT-PCR. Finally we explored the potential of the core genes as pan-cancer biomarkers.

Our efforts culminated in the establishment of a validated 17-gene ADME-centered risk prediction model, displaying remarkable predictive accuracy for BLCA prognosis. Through separate cox regression analyses, the importance of the model's risk score in forecasting BLCA outcomes was substantiated. Furthermore, a novel nomogram incorporating clinical variables alongside the risk score was introduced. Comprehensive studies established a strong correlation between the risk score and several key indicators: patterns of immune cell infiltration, reactions to immunotherapy, landscape of somatic mutation and profiles of drug sensitivity. We screened the core prognostic gene CYP2C8, explored its role in tumor bioregulation and validated its upregulated expression in bladder cancer. Furthermore, we found that it can serve as a reliable biomarker for pan-cancer.

The risk assessment model formulated in our research stands as a formidable instrument for forecasting BLCA prognosis, while also providing insights into the disease's progression mechanisms and guiding clinical decision-making strategies.

Pancreatic ductal adenocarcinoma (PDAC) has a poor survival rate and limited treatments. Agonistic CD40 antibodies are promising, but clinical trials have shown only modest efficacy and significant hepatotoxicity. We previously reported that IL-1 pathway blockade enhances agonistic CD40 antibody efficacy against melanoma by depleting polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs; CD11b+Ly6C+Ly6G+). Because PMN-MDSCs also cause liver toxicity, we investigated the impact of IL-1R1 blockade on the efficacy and toxicity of agonistic CD40 antibody therapy in PDAC. Agonistic CD40 antibody therapy induced immune activation and significantly prolonged survival in orthotopic PDAC-bearing mice. IL-1R1 blockade monotherapy downregulated innate and adaptive immune response and exacerbated tumor growth. Although combination therapy upregulated several immune-related pathways and boosted innate and adaptive immune responses. IL-1R1 blockade failed to improve the overall antitumor efficacy of agonistic CD40 antibody therapy and exacerbated liver toxicity. Ly6G+ cell depletion in mice reduced the efficacy of agonistic CD40 antibody therapy, suggesting that Ly6G+ immune cells (PMN-MDSCs or neutrophils) exhibit an antitumor rather than immunosuppressive role in PDAC. Our findings underscore the complex role of IL-1 signaling in modulating immune responses in PDAC and caution against pursuing IL-1R1 blockade, either as monotherapy or combined with agonistic CD40 antibodies, in clinical trials for PDAC.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging zoonotic pathogen with different pathogenesis in humans and camels. The mechanisms behind the higher tolerance of camels to MERS-CoV infection are still unknown. Monocytes are innate myeloid cells that are able, depending on the local stimulation in their microenvironment, to differentiate into different functional subtypes of macrophages with an impact on the adaptive immune response. Several in vitro protocols have been used to induce the differentiation of monocyte-derived macrophages (MDMs) in human and several veterinary species. Such protocols are not available for camel species. In the present study, monocytes were separated from camel blood and differentiated in vitro in the presence of different stimuli into MDM. Camel MDMs generated in the presence of a combined stimulation of monocytes with LPS and GM-CSF resulted in the development of an M1 macrophages phenotype with increased abundance of the antigen-presentation receptor MHCII molecules and a decreased expression of the scavenger receptor CD163. The expression pattern of the cell markers CD163, CD14, CD172a, CD44, and CD9 on MDM generated in the presence of the MERS-CoV S1 protein revealed similarity with M-CSF-induced MDM, suggesting the potential of the MERS-CoV S1 protein to induce an M2 macrophages phenotype. Similarly to the effect of M-CSF, MERS-CoV-S protein-induced MDMs showed enhanced phagocytosis activity compared to non-polarized or LPS/GM-CSF-polarized MDMs. Collectively, our study represents the first report on the in vitro generation of monocyte-derived macrophages (MDMs) in camels and the characterization of some phenotypic and functional properties of camel MDM under the effect of M1 and M2 polarizing stimuli. In addition, the results suggest a polarizing effect of the MERS-CoV S1 protein on camel MDMs, developing an M2-like phenotype with enhanced phagocytosis activity. To understand the clinical relevance of these in vitro findings on disease pathogenesis and camel immune response toward MERS-CoV infection, further studies are required.

Pancreatic adenocarcinoma (PAAD) is a highly lethal malignancy with an immunosuppressive microenvironment and a limited immunotherapy response. Cholesterol is necessary for rapid growth of cancer cells, and cholesterol metabolism reprogramming is a hallmark of PAAD. How PAAD cells initiate cholesterol reprogramming to sustain their growth demand and suppressive immunomicroenvironment remains elusive. In this study, we for the first time revealed that PAAD cells overcome cholesterol shortage and immune surveillance via ectopically overexpressing NPC1L1, a cholesterol transporter, but function as a two-pronged checkpoint, which not only directly suppresses TCR activation of CD8+T cells but also hijacks the intracellular cholesterol from CD8+T cells. In vivo, we showed that ezetimibe, an NPC1L1 inhibitor usually for hypercholesterolemia, efficiently prevented PAAD cells from depriving cholesterol of CD8+T cells, and improved the anti-tumor immunity of PAAD to synergize with PD-1 blockade, suggesting NPC1L1 as a promising target to rescue the anti-tumor activity in PAAD.

Bispecific antibodies (BsAbs) represent a promising strategy for cancer immunotherapy. Challenges in immunotherapy include inefficient early events in the immune response cycle, such as antigen presentation and T cell priming. Background stimulation of CD40 with agonistic antibodies is a promising strategy to enhance the therapeutic efficacy of immune checkpoint inhibitors (ICIs). Assisted by Alphafold2(AlphaFold-Multimer), we developed a humanized CD40 agonistic antibody that exhibits activation only in the presence of cross-linking. It also demonstrates that the current AlphaFold2(AlphaFold2-Multimer) can predict antibody-antigen complexes. Due to the unique epitope, it demonstrates superior activation compared to APX005M (S267E). Building upon this, we created a novel bispecific antibody (anti-PD-L1/CD40 bispecific antibody, referred to as "BA4415") designed to activate CD40 signaling specifically in the context of PD-L1 while simultaneously blocking PD-1/PD-L1 signaling. Results from functional evaluations using effector cells revealed the superior biological activity of BA4415 compared to the combination of each monoclonal antibody. BA4415 demonstrated the ability to enhance T-cell cytokine release in vitro assays, exhibiting superior functional attributes compared to the anti-PD-L1 antibody. Furthermore, in humanized transgenic mice challenged with huPD-L1-expressing tumor cells, BA4415 induced superior anti-tumor activity. This novel anti-PD-L1/CD40 bispecific antibody holds potential for strong anti-tumor therapeutic efficacy by selectively restricting CD40 stimulation in tumors.

Macrophages are present at high frequency in most solid tumor types, and their relative abundance negatively correlates with therapy responses and survival outcomes. Tissue-resident macrophages are highly tuned to integrate tissue niche signals, and multiple factors within the idiosyncratic tumor microenvironment (TME) drive macrophages to polarization states that favor immune suppression, tumor growth and metastasis. These diverse functional states are underpinned by extensive and complex rewiring of tumor-associated macrophage (TAM) metabolism. In this Review, we link distinct and specific macrophage functional states within the TME to major, phenotype-sustaining metabolic programs and discuss the metabolic impact of macrophage-modulating therapeutic interventions.

Oncolytic virus (OV) mediated immunotherapy is one of the recent techniques used to treat higher grade cancers where conventional therapies like chemotherapy, radiation fail. OVs as a therapeutic tool show high efficacy and fewer side effects than conventional methods as supported by multiple preclinical and clinical studies since they are engineered to target tumours. In this chapter, we discuss the modifications in viruses to make them oncolytic, types of strains commonly administered, mechanisms employed by viruses to specifically target and eradicate malignancy and progress achieved as reported in case studies (preclinical and clinical trials). OVs also face some unique challenges with respect to the malignancy being treated and the varied pathogen exposure of the patients, which is also highlighted here. Since pathogen exposure varies according to population dynamics worldwide, chances of generating a non-specific recall response to an OV cannot be negated. Lastly, the future perspectives and ongoing practises of combination therapies are discussed as they provide a leading edge over monotherapies in terms of tumour clearance, blocking metastasis and enhancing patient survival. Efforts undertaken to overcome current challenges are also highlighted.

Pancreatic cancer (PC) is characterised by late diagnosis, tumour heterogeneity, and a peculiar immunosuppressive microenvironment, leading to poor clinical outcomes. Local ablative techniques have been proposed to treat unresectable PC patients, although their impact on activating the host immune system and overcoming resistance to immunotherapy remains elusive.

We dissected the immune-modulatory abilities triggered by local ablation in mouse and human PC models and human specimens, integrating phenotypic and molecular technologies with functional assays.

Local ablation treatment performed in mice bearing orthotopic syngeneic PC tumours triggered tumour necrosis and a short-term inflammatory process characterised by the prompt increase of HMGB1 plasma levels, coupled with an enhanced amount of circulating and tumour infiltrating myeloid cells and increased MHCII expression in splenic myeloid antigen-presenting cells. Local ablation synergised with immunotherapy to restrict tumour progression and improved the survival of PC-bearing mice by evoking a T lymphocyte-dependent anti-tumour immune response. By integrating spatial transcriptomics with histological techniques, we pinpointed how combination therapy could reshape TME towards an anti-tumour milieu characterised by the preferential entrance and colocalization of activated T lymphocytes and myeloid cells endowed with antigen presentation features instead of T regulatory lymphocytes and CD206-expressing tumour-associated macrophages. In addition, treatment-dependent TME repolarization extended to neoplastic cells, promoting a shift from squamous to a more differentiated classical phenotype. Finally, we validated the immune regulatory properties induced by local ablation in PC patients and identified an association of the short-term treatment-dependent increase of neutrophils, NLR and HMGB1 with a longer time to progression.

Therefore, local ablation might overcome the current limitations of immunotherapy in PC.

The tumor microenvironment (TME) is integral to cancer progression, impacting metastasis and treatment response. It consists of diverse cell types, extracellular matrix components, and signaling molecules that interact to promote tumor growth and therapeutic resistance. Elucidating the intricate interactions between cancer cells and the TME is crucial in understanding cancer progression and therapeutic challenges. A critical process induced by TME signaling is the epithelial-mesenchymal transition (EMT), wherein epithelial cells acquire mesenchymal traits, which enhance their motility and invasiveness and promote metastasis and cancer progression. By targeting various components of the TME, novel investigational strategies aim to disrupt the TME's contribution to the EMT, thereby improving treatment efficacy, addressing therapeutic resistance, and offering a nuanced approach to cancer therapy. This review scrutinizes the key players in the TME and the TME's contribution to the EMT, emphasizing avenues to therapeutically disrupt the interactions between the various TME components. Moreover, the article discusses the TME's implications for resistance mechanisms and highlights the current therapeutic strategies toward TME modulation along with potential caveats.

To develop pH (pHe)-triggered membrane adhesive nanoliposome (pHTANL) of CD40a to enhance anti-tumor activity in pancreatic cancer while reducing systemic toxicity.

A small library of nanoliposomes (NL) with various lipid compositions were synthesized to prepare pH (pHe)-triggered membrane adhesive nanoliposome (pHTANL). Physical and functional characterization of pHTANL-CD40a was performed via dynamic light scattering (DLS), Transmission Electron Microscopy (TEM), confocal microscopy, and flow cytometry. In vivo studies were performed using PDAC (Panc02) transplanted mice. Tumor tissue was analyzed by flow cytometry, and plasma cytokines and liver enzymes were analyzed by ELISA.

pHTANL-CD40a reduced tumor growth, enhanced tumor immune infiltration/activation, and enhanced survival compared to vehicle and free-CD40a. Importantly, pHTANL-CD40a treatment resulted in significantly lower systemic toxicity as indicated by unchanged body weight, minimal organ deformity, and reduced serum levels of liver enzyme alanine transaminase (ALT) and inflammatory cytokine IL-6.

pHTANL-CD40a is more effective than free CD40a in anti-tumor activity, especially in altering the TME immune landscape for a potential therapeutic benefit in combination with immunotherapy.

Genetically engineered mouse models (GEMMs) are instrumental for modelling local and systemic features of complex diseases, such as cancer. Non-invasive, longitudinal cell detection and monitoring in tumors, metastases and/or the micro-environment is paramount to achieve a better spatiotemporal understanding of cancer progression and to evaluate therapies in preclinical studies. Bioluminescent and fluorescent reporters marking tumor cells or their microenvironment are valuable for non-invasive cell detection and monitoring in vivo. Here, we report the generation of a dual reporter allele allowing simultaneous bioluminescence and fluorescence detection of cells that have undergone Cre-Lox recombination in mice. The single copy knock-in allele in the permissive collagen I locus was evaluated in the context of several cancer GEMMs, where Cre expression was achieved genetically or by ectopic virus-mediated delivery. The new reporter allele was also combined with gene-targeted alleles widely used in bone, prostate, brain and pancreas cancer research, as well as with alleles inserted into the commonly used Rosa26 and collagen I loci. This allele is, therefore, a useful addition to the portfolio of reporters to help advance preclinical research.

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related deaths with a 5-year survival rate of 13%. Surgical resection remains the only curative option as systemic therapies offer limited benefit. Poor response to chemotherapy and immunotherapy is due, in part, to the dense stroma and heterogeneous tumor microenvironment (TME). Opportunities to target the PDAC stroma may increase the effectiveness of existing or novel therapies. Current strategies targeting the stromal compartment within the PDAC TME primarily focus on degrading extracellular matrix or inhibiting stromal cell activity, angiogenesis, or hypoxic responses. In addition, extensive work has attempted to use immune targeting strategies to improve clinical outcomes. Preclinically, these strategies show promise, especially with the ability to alter the tumor ecosystem; however, when translated to the clinic, most of these trials have failed to improve overall patient outcomes. In this review, we catalog the heterogenous elements of the TME and discuss the potential of combination therapies that target the heterogeneity observed in the TME between patients and how molecular stratification could improve responses to targeted and combination therapies.

Essential membrane components and metabolites with a wide range of biological roles are both produced by cholesterol metabolism. Cell-intrinsic and cell-extrinsic stimuli alter cholesterol metabolism in the tumor microenvironment (TME), which in turn encourages colorectal carcinogenesis. Metabolites produced from cholesterol play intricate roles in promoting the development of colorectal cancer (CRC) and stifling immunological responses. By altering the extracellular matrix of the main tumor, redesigning its immunological environment, and altering its mechanical stiffness, cholesterol can encourage the epithelial-mesenchymal transition of the primary tumor, opening up a pathway for tumor metastasis. Its functions in TME remodeling and tumor prevention have been recently identified. In this review we address the function of cholesterol in TME remodeling and therapeutic techniques designed to block cholesterol metabolism, and discuss how combining these strategies with already available anti-CRC medicines can have combined effects and open up new therapeutic avenues.

The role of myeloid cells in tumor immunity is multifaceted. While dendritic cells support T cell-mediated tumor control, the highly heterogenous populations of macrophages, neutrophils, and immature myeloid cells were generally considered immunosuppressive. This view has led to effective therapies reinvigorating tumor-reactive T cells; however, targeting the immunosuppressive effects of macrophages and neutrophils to boost the cancer immunity cycle was clinically less successful. Recent studies interrogating the role of immune cells in the context of successful immunotherapy affirm the key role of T cells, but simultaneously challenge the idea that the cytotoxic function of T cells is the main contributor to therapy-driven tumor regression. Rather, therapy-activated intra-tumoral T cells recruit and activate or reprogram several myeloid effector cell types, the presence of which is necessary for tumor rejection. Here, we reappreciate the key role of myeloid effector cells in tumor rejection as this may help to shape future successful immunotherapies.

Trained immunity (TI) is functional memory displayed by innate immune cells (IICs). TI facilitates rapid, non-specific responses to pathogens upon secondary challenge. It is driven by immunological signaling and metabolic rewriting via epigenetic alteration, triggered by recognition of certain stimuli. Recently, immune checkpoint inhibitors have come into common use in clinical oncology settings, and genetically engineered cytotoxic T cells comprise a potent cancer treatment strategy. However, the contributions of TI in the tumor microenvironment (TME) are only beginning to be uncovered. Accumulating evidence that various microorganisms and vaccines convey tumoricidal ability suggest that TI may become a useful anti-cancer tool. The expected roles of TI in tumor therapy are the 1) promotion of proinflammatory cytokine section, 2) enhancement of phagocytosis, 3) quick expansion and recruitment of cancer-specific cytotoxic T cells to the TME through neoantigen presentation, 4) reversal of immunosuppression in the TME, and 5) removal of pathogens associated with carcinogenesis or tumor development. Medium- to long-term TI durability may reduce the risk of tumor development. Recent findings on TI usher in new aspirations for cancer treatment.

The advent of checkpoint therapy is one of the most important recent advancements in cancer therapy. Though checkpoint therapy is a mainstay in some cancers, it has been largely ineffective in treating cancers of the pancreas. Pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumors are seldom responsive to checkpoint inhibition.

Here we present two cases of advanced pancreatic cancers that either failed to respond or recurred following conventional treatments. Tissue from each tumor was sequenced and analyzed for PD-L1 expression. Each patient was started on checkpoint blockade after assessing for a predictive biomarker, either the combined positive score or the tumor mutational burden. In each case, checkpoint blockade led to durable radiographic responses.

We therefore propose that it is reasonable to assess combined positive score and tumor mutational burden in refractory or recurrent pancreatic cancers when initiation of ICB is being considered.

Despite the notable efficacy of anti-PD1 therapy in the management of hepatocellular carcinoma (HCC) patients, resistance in most individuals necessitates additional investigation. For this study, we collected tumor tissues from nine HCC patients receiving anti-PD1 monotherapy and conducted RNA sequencing. These findings revealed significant upregulation of GSDME, which is predominantly expressed by tumor-associated macrophages (TAMs), in anti-PD1-resistant patients. Furthermore, patients with elevated levels of GSDME+ macrophages in HCC tissues presented a poorer prognosis. The analysis of single-cell sequencing data and flow cytometry revealed that the suppression of GSDME expression in nontumor cells resulted in a decrease in the proportion of M2-like macrophages within the tumor microenvironment (TIME) of HCC while concurrently augmenting the cytotoxicity of CD8 + T cells. The non-N-terminal fragment of GSDME within macrophages combines with PDPK1, thereby activating the PI3K-AKT pathway and facilitating M2-like polarization. The small-molecule Eliprodil inhibited the increase in PDPK1 phosphorylation mediated by GSDME site 1. The combination of Eliprodil and anti-PD1 was effective in the treatment of both spontaneous HCC in c-Myc + /+;Alb-Cre + /+ mice and in a hydrodynamic tail vein injection model, which provides a promising strategy for novel combined immunotherapy.

АBSTRACT: With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.

Macrophages engulf apoptotic bodies and cellular debris as part of homeostasis, but they can also phagocytose live cells such as aged red blood cells. Pharmacologic reprogramming with the SMAC mimetic LCL161 in combination with T cell-derived cytokines can induce macrophages to phagocytose live cancer cells in mouse models. Here we extend these findings to encompass a wide range of monovalent and bivalent SMAC mimetic compounds, demonstrating that live cell phagocytosis is a class effect of these agents. We demonstrate robust phagocytosis of live pancreatic and breast cancer cells by primary human macrophages across a range of healthy donors. Unlike mouse macrophages where combination of SMAC mimetics with lymphotoxin enhanced phagocytosis, human macrophages were more efficiently polarized to phagocytose live cells by the combination of SMAC mimetics and IFNψ. We profiled phagocytic macrophages by transcriptional and proteomic methodologies, uncovering a positive feedback loop of autocrine TNFα production.

Idiopathic inflammatory myopathies are a group of systemic autoimmune diseases characterized by chronic muscle inflammation and diverse clinical manifestations. Macrophages, pivotal components of innate immunity, are implicated in immune responses, inflammation resolution, and tissue repair. Distinct macrophage polarization states play vital roles in disease progression and resolution. Mechanistically, activated macrophages release proinflammatory cytokines, chemokines, and reactive oxygen species, perpetuating immune responses and tissue damage. Dysregulated macrophage polarization contributes to sustained inflammation. Here, we reviewed the intricate contributions of macrophages to IIM pathogenesis and explored novel therapeutic avenues. We discussed emerging strategies targeting macrophages, including receptor-based interventions and macrophage polarization modulation, for IIM treatment. This review underscores the multifaceted involvement of macrophages in IIM pathogenesis and offers insights into potential therapeutic approaches targeting these immune cells for disease management.

Acute myeloid leukemia (AML) is a malignant tumor with high recurrence and refractory rates and low survival rates. Increased glycolysis is characteristic of metabolism in AML blast cells and is also associated with chemotherapy resistance. The purpose of this study was to use gene expression and clinical information from The Cancer Genome Atlas (TCGA) database to identify subtypes of AML associated with lactate metabolism. Two different subtypes linked to lactate metabolism, each with specific immunological features and consequences for prognosis, were identified in this study. Using the TCGA and International Cancer Genome Consortium (GEO) cohorts, a prognostic model composed of genes (LMNA, RETN and HK1) for the prognostic value of the lactate metabolism-related risk score prognostic model was created and validated, suggesting possible therapeutic uses. Additionally, the diagnostic value of the prognostic model genes was explored. LMNA and HK1 were ultimately identified as hub genes, and their roles in AML were determined through immune infiltration, GeneMANIA, GSEA, methylation analysis and single-cell analysis. LMNA was upregulated in AML associating with a poor prognosis while HK1 was downregulated in AML associating with a favorable prognosis. The findings underscore the noteworthy impact of genes linked to lactate metabolism in AML and illustrate the possible therapeutic usefulness of the lactate metabolism-related risk score and the hub lactate metabolism-related genes in guiding AML patients' treatment choices.

Associations between inflammation and cancer were first discovered approximately 160 years ago by Rudolf Virchow, who observed that tumors were infiltrated with inflammatory cells, and defined inflammation as a pathological condition. Inflammation has now emerged as one of the key mediators in oncogenesis and tumor progression, including pancreatic ductal adenocarcinoma (PDAC). However, the role of inflammatory processes in cancers is complicated and controversial, and the detailed regulatory mechanisms are still unclear. This review elucidates the dynamic interplay between inflammation and immune regulation, microenvironment alteration, metabolic reprogramming, and microbiome risk factors in PDAC, committing to exploring a deeper understanding of the role of crucial inflammatory pathways and molecules for providing insights into therapeutic strategies.

Endometriosis negatively impacts the health-related quality of life of 190 million women worldwide. Novel advances in nonhormonal treatments for this debilitating condition are desperately needed. Macrophages play a vital role in the pathophysiology of endometriosis and represent a promising therapeutic target. In the current study, we revealed the full transcriptomic complexity of endometriosis-associated macrophage subpopulations using single-cell analyses in a preclinical mouse model of experimental endometriosis. We have identified two key lesion-resident populations that resemble i) tumor-associated macrophages (characterized by expression of Folr2, Mrc1, Gas6, and Ccl8+) that promoted expression of Col1a1 and Tgfb1 in human endometrial stromal cells and increased angiogenic meshes in human umbilical vein endothelial cells, and ii) scar-associated macrophages (Mmp12, Cd9, Spp1, Trem2+) that exhibited a phenotype associated with fibrosis and matrix remodeling. We also described a population of proresolving large peritoneal macrophages that align with a lipid-associated macrophage phenotype (Apoe, Saa3, Pid1) concomitant with altered lipid metabolism and cholesterol efflux. Gain of function experiments using an Apoe mimetic resulted in decreased lesion size and fibrosis, and modification of peritoneal macrophage populations in the preclinical model. Using cross-species analysis of mouse and human single-cell datasets, we determined the concordance of peritoneal and lesion-resident macrophage subpopulations, identifying key similarities and differences in transcriptomic phenotypes. Ultimately, we envisage that these findings will inform the design and use of specific macrophage-targeted therapies and open broad avenues for the treatment of endometriosis.

Published in Cancer Research in 2007, Clark and colleagues first introduced the concept that the immune microenvironment evolves in lockstep with the progression of pancreatic cancer. Leveraging genetically engineered mouse models of the disease that were described a few years earlier, Clark and colleagues used a combination of approaches to describe the dynamics of immune evolution in precursor lesions all the way to overt malignancy. They discovered that immunosuppression is established at the earliest stages of carcinogenesis. Here, we discuss their findings, how they led to a wealth of functional work, and how they have been expanded upon since the advent of -omics technologies. See related article by Clark and colleagues, Cancer Res 2007;67:9518-27.

Pancreatic ductal adenocarcinoma (PDAC) presents a fatal clinical challenge characterized by a dismal 5-year overall survival rate, primarily due to the lack of early diagnosis and limited therapeutic efficacy. Immunotherapy, a proven success in multiple cancers, has yet to demonstrate significant benefits in PDAC. Recent studies have revealed the immunosuppressive characteristics of the PDAC tumor microenvironment (TME), including immune cells with suppressive properties, desmoplastic stroma, microbiome influences, and PDAC-specific signaling pathways. In this article, we review recent advances in understanding the immunosuppressive TME of PDAC, TME differences among various mouse models of pancreatic cancer, and the mechanisms underlying resistance to immunotherapeutic interventions. Furthermore, we discuss the potential of targeting cancer cell-intrinsic pathways and TME components to sensitize PDAC to immune therapies, providing insights into strategies and future perspectives to break through the barriers in improving pancreatic cancer treatment.

Macrophage-based cell therapy is promising in solid tumors, but the efficient acquisition of macrophages remains a challenge. Induced pluripotent stem cell (iPSC)-induced macrophages are a valuable source, but time-consuming and costly. The application of reprogramming technologies allows for the generation of macrophages from somatic cells, thereby facilitating the advancement of cell-based therapies for numerous malignant diseases.

The composition of CD45+ myeloid-like cell complex (MCC) and induced macrophage (iMac) were analyzed by flow cytometry and single-cell RNA sequencing. The engraftment capacity of CD45+ MCC was evaluated by two transplantation assays. Regulation of c-Myc on MafB was evaluated by ChIP-qPCR and promoter reporter and dual luciferase assays. The phenotype and phagocytosis of iMac were explored by flow cytometry and immunofluorescence. Leukemia, breast cancer, and patient-derived tumor xenograft models were used to explore the anti-tumor function of iMac.

Here we report on the establishment of a novel methodology allowing for reprogramming fibroblasts into functional macrophages with phagocytic activity by c-Myc overexpression. Fibroblasts with ectopic expression of c-Myc in iPSC medium rapidly generated CD45+ MCC intermediates with engraftment capacity as well as the repopulation of distinct hematopoietic compartments. MCC intermediates were stably maintained in iPSC medium and continuously generated functional and highly pure iMac just by M-CSF cytokine stimulation. Single-cell transcriptomic analysis of MCC intermediates revealed that c-Myc up-regulated the expression of MafB, a major regulator of macrophage differentiation, to promote macrophage differentiation. Characterization of the iMac activity showed NF-κB signaling activation and a pro-inflammatory phenotype. iMac cells displayed significantly increased in vivo persistence and inhibition of tumor progression in leukemia, breast cancer, and patient-derived tumor xenograft models.

Our findings demonstrate that c-Myc alone is enough to reprogram fibroblasts into functional macrophages, supporting that c-Myc reprogramming strategy of fibroblasts can help circumvent long-standing obstacles to gaining "off-the-shelf" macrophages for anti-cancer immunotherapy.

Highly malignant pancreatic ductal adenocarcinoma (PDAC) is characterised by an abundant immunosuppressive and fibrotic tumour microenvironment (TME). Future therapeutic attempts will therefore demand the targeting of tumours and stromal compartments in order to be effective. Here we investigate whether dual specificity and tyrosine phosphorylation-regulated kinase 1B (DYRK1B) fulfil these criteria and represent a promising anticancer target in PDAC.

We used transplantation and autochthonous mouse models of PDAC with either genetic Dyrk1b loss or pharmacological DYRK1B inhibition, respectively. Mechanistic interactions between tumour cells and macrophages were studied in direct or indirect co-culture experiments. Histological analyses used tissue microarrays from patients with PDAC. Additional methodological approaches included bulk mRNA sequencing (transcriptomics) and proteomics (secretomics).

We found that DYRK1B is mainly expressed by pancreatic epithelial cancer cells and modulates the influx and activity of TME-associated macrophages through effects on the cancer cells themselves as well as through the tumour secretome. Mechanistically, genetic ablation or pharmacological inhibition of DYRK1B strongly attracts tumoricidal macrophages and, in addition, downregulates the phagocytosis checkpoint and 'don't eat me' signal CD24 on cancer cells, resulting in enhanced tumour cell phagocytosis. Consequently, tumour cells lacking DYRK1B hardly expand in transplantation experiments, despite their rapid growth in culture. Furthermore, combining a small-molecule DYRK1B-directed therapy with mammalian target of rapamycin inhibition and conventional chemotherapy stalls the growth of established tumours and results in a significant extension of life span in a highly aggressive autochthonous model of PDAC.

In light of DYRK inhibitors currently entering clinical phase testing, our data thus provide a novel and clinically translatable approach targeting both the cancer cell compartment and its microenvironment.