Identification of unique neoantigen qualities in long-term survivors of pancreatic cancer

T lymphocyte‑related immune response and immunotherapy in gastric cancer (Review)

Gastric cancer (GC) remains a global healthcare challenge because of its high incidence and poor prognosis. The efficacy of current chemotherapy regimens for advanced GC is limited. T cells, which have been implicated in the progression of GC, have a significant impact in the tumor microenvironment. With a more detailed understanding of the mechanisms underlying the cancer immunoediting process, immunotherapy may become a promising treatment option for patients with GC. Several clinical trials are currently investigating different mechanisms targeting the tumor immune response. The present review summarized T cell-involved immune responses and various immunotherapy strategies for GC.

Tumour mutational burden: clinical utility, challenges and emerging improvements

Tumour mutational burden (TMB), defined as the total number of somatic non-synonymous mutations present within the cancer genome, varies across and within cancer types. A first wave of retrospective and prospective research identified TMB as a predictive biomarker of response to immune-checkpoint inhibitors and culminated in the disease-agnostic approval of pembrolizumab for patients with TMB-high tumours based on data from the Keynote-158 trial. Although the applicability of outcomes from this trial to all cancer types and the optimal thresholds for TMB are yet to be ascertained, research into TMB is advancing along three principal avenues: enhancement of TMB assessments through rigorous quality control measures within the laboratory process, including the mitigation of confounding factors such as limited panel scope and low tumour purity; refinement of the traditional TMB framework through the incorporation of innovative concepts such as clonal, persistent or HLA-corrected TMB, tumour neoantigen load and mutational signatures; and integration of TMB with established and emerging biomarkers such as PD-L1 expression, microsatellite instability, immune gene expression profiles and the tumour immune contexture. Given its pivotal functions in both the pathogenesis of cancer and the ability of the immune system to recognize tumours, a profound comprehension of the foundational principles and the continued evolution of TMB are of paramount relevance for the field of oncology.

Updates in Molecular Profiling of Pancreatic Ductal Adenocarcinoma

Outcomes from pancreatic ductal adenocarcinoma (PDAC) remain poor and better methods of prognostication and therapeutic approaches are needed. Recent advances in cancer genomics have led to the development of molecular subtypes of PDAC associated with clinical outcomes. Current evidence also suggests that the subtypes have differential response to first-line chemotherapy regimens. PDAC is also characterized by different stroma and immune environments. Further work is needed to confirm the utility of these subtypes to predicting response to different systemic therapies.

Identification of immunogenic HLA class I and II neoantigens using surrogate immunopeptidomes

Neoantigens arising from somatic mutations are tumor specific and induce antitumor host T cell responses. However, their sequences are individual specific and need to be identified for each patient for therapeutic applications. Here, we present a proteogenomic approach for neoantigen identification, named Neoantigen Selection using a Surrogate Immunopeptidome (NESSIE). This approach uses an autologous wild-type immunopeptidome as a surrogate for the tumor immunopeptidome and allows human leukocyte antigen (HLA)-agnostic identification of both HLA class I (HLA-I) and HLA class II (HLA-II) neoantigens. We demonstrate the direct identification of highly immunogenic HLA-I and HLA-II neoantigens using NESSIE in patients with colorectal cancer and endometrial cancer. Fresh or frozen tumor samples are not required for analysis, making it applicable to many patients in clinical settings. We also demonstrate tumor prevention by vaccination with selected neoantigens in a preclinical mouse model. This approach may benefit personalized T cell-mediated immunotherapies.

Pancreatic ductal adenocarcinoma cells reshape the immune microenvironment: Molecular mechanisms and therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is a digestive system malignancy characterized by challenging early detection, limited treatment alternatives, and generally poor prognosis. Although there have been significant advancements in immunotherapy for hematological malignancies and various solid tumors in recent decades, with impressive outcomes in recent preclinical and clinical trials, the effectiveness of these therapies in treating PDAC continues to be modest. The unique immunological microenvironment of PDAC, especially the abnormal distribution, complex composition, and variable activation states of tumor-infiltrating immune cells, greatly restricts the effectiveness of immunotherapy. Undoubtedly, integrating data from both preclinical models and human studies helps accelerate the identification of reliable molecules and pathways responsive to targeted biological therapies and immunotherapies, thereby continuously optimizing therapeutic combinations. In this review, we delve deeply into how PDAC cells regulate the immune microenvironment through complex signaling networks, affecting the quantity and functional status of immune cells to promote immune escape and tumor progression. Furthermore, we explore the multi-modal immunotherapeutic strategies currently under development, emphasizing the transformation of the immunosuppressive environment into an anti-tumor milieu by targeting specific molecular and cellular pathways, providing insights for the development of novel treatment strategies.

Spatial Heterogeneity of Immune Regulators Drives Dynamic Changes in Local Immune Responses, Affecting Disease Outcomes in Pancreatic Cancer

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is considered a low-immunogenic (LI) tumor with a "cold" tumor microenvironment and is mostly unresponsive to immune checkpoint blockade therapies. In this study, we decipher the impact of intratumoral heterogeneity of immune determinants on antitumor responses.

EXPERIMENTAL DESIGN

We performed spatial proteomic and transcriptomic analyses and multiplex immunofluorescence on multiple tumor regions, including tumor center (TC) and invasive front (IF), from 220 patients with PDAC, classified according to their transcriptomic immune signaling into high-immunogenic PDAC (HI-PDAC, n = 54) and LI PDAC (LI-PDAC, n = 166). Spatial compartments (tumor: pancytokeratin+/CD45- and leukocytes: pancytokeratin-/CD45+) were defined by fluorescence imaging.

RESULTS

HI-PDAC exhibited higher densities of cytotoxic T lymphocytes with upregulation of T-cell priming-associated immune determinants, including CD40, ITGAM, glucocorticoid-induced TNF-related receptor, CXCL10, granzyme B, IFNG, and HLA-DR, which were significantly more prominent at the IF than at the TC. In contrast, LI-PDAC exhibited immune-evasive tumor microenvironments with downregulation of immune determinants and a negative gradient from TC to IF. Patients with HI-PDAC had significantly better outcomes but showed more frequently exhausted immune phenotypes.

CONCLUSIONS

Our results indicate strategic differences in the regulation of immune determinants, leading to different levels of effectiveness of antitumor responses between HI and LI tumors and dynamic spatial changes, which affect the evolution of immune evasion and patient outcomes. This finding supports the coevolution of tumor and immune cells and may help define therapeutic vulnerabilities to improve antitumor immunity and harness the responsiveness to immune checkpoint inhibitors in patients with PDAC.

Microbiome modulation of antigen presentation in tolerance and inflammation

The microbiome regulates mammalian immune responses from early life to adulthood. Antigen presentation, orchestrating these responses, integrates commensal and pathogenic signals. However, the temporal and spatial specificity of microbiome impacts on antigen presentation and downstream tolerance versus inflammation remain incompletely understood. Herein, we review the influences of antigen presentation of microbiome-related epitopes on immunity; impacts of microbiome-based modulation of antigen presentation on innate and adaptive immune responses; and their ramifications on homeostasis and immune-related disease, ranging from auto-inflammation to tumorigenesis. We highlight mechanisms driving these influences, such as 'molecular mimicry', in which microbiome auto-antigen presentation aberrantly triggers an immune response driving autoimmunity or influences conferred by microbiome-derived metabolites on antigen-presenting cells in inflammatory bowel disease. We discuss unknowns, controversies, and challenges associated with the study of microbiome regulation of antigen presentation while demonstrating how increasing knowledge may contribute to the development of microbiome-based therapeutics modulating immune responses in a variety of clinical contexts.

Biological Barriers for Drug Delivery and Development of Innovative Therapeutic Approaches in HIV, Pancreatic Cancer, and Hemophilia A/B

Biological barriers remain a major obstacle for the development of innovative therapeutics. Depending on a disease's pathophysiology, the involved tissues, cell populations, and cellular components, drugs often have to overcome several biological barriers to reach their target cells and become effective in a specific cellular compartment. Human biological barriers are incredibly diverse and include multiple layers of protection and obstruction. Importantly, biological barriers are not only found at the organ/tissue level, but also include cellular structures such as the outer plasma membrane, the endolysosomal machinery, and the nuclear envelope. Nowadays, clinicians have access to a broad arsenal of therapeutics ranging from chemically synthesized small molecules, biologicals including recombinant proteins (such as monoclonal antibodies and hormones), nucleic-acid-based therapeutics, and antibody-drug conjugates (ADCs), to modern viral-vector-mediated gene therapy. In the past decade, the therapeutic landscape has been changing rapidly, giving rise to a multitude of innovative therapy approaches. In 2018, the FDA approval of patisiran paved the way for small interfering RNAs (siRNAs) to become a novel class of nucleic-acid-based therapeutics, which-upon effective drug delivery to their target cells-allow to elegantly regulate the post-transcriptional gene expression. The recent approvals of valoctocogene roxaparvovec and etranacogene dezaparvovec for the treatment of hemophilia A and B, respectively, mark the breakthrough of viral-vector-based gene therapy as a new tool to cure disease. A multitude of highly innovative medicines and drug delivery methods including mRNA-based cancer vaccines and exosome-targeted therapy is on the verge of entering the market and changing the treatment landscape for a broad range of conditions. In this review, we provide insights into three different disease entities, which are clinically, scientifically, and socioeconomically impactful and have given rise to many technological advancements: acquired immunodeficiency syndrome (AIDS) as a predominant infectious disease, pancreatic carcinoma as one of the most lethal solid cancers, and hemophilia A/B as a hereditary genetic disorder. Our primary objective is to highlight the overarching principles of biological barriers that can be identified across different disease areas. Our second goal is to showcase which therapeutic approaches designed to cross disease-specific biological barriers have been promising in effectively treating disease. In this context, we will exemplify how the right selection of the drug category and delivery vehicle, mode of administration, and therapeutic target(s) can help overcome various biological barriers to prevent, treat, and cure disease.

The Road Ahead in Pancreatic Cancer: Emerging Trends and Therapeutic Prospects

This review explores the challenges and emerging trends in pancreatic cancer therapy. In particular, we focus on the tumor microenvironment and the potential of immunotherapy for pancreatic cancer. Pancreatic ductal adenocarcinoma, characterized by its dense stromal architecture, presents unique challenges for effective treatment. Recent advancements have emphasized the role of the tumor microenvironment in therapeutic resistance and disease progression. We discuss novel strategies targeting the desmoplastic barrier and immunosuppressive cells to enhance immune cell infiltration and activation. Recent clinical trials, particularly those involving novel immunotherapeutic agents and tumor vaccines, are examined to understand their efficacy and limitations. Our analysis reveals that combining immunotherapy with chemotherapy, radiation therapy, or drugs targeting epigenetic processes shows promise, improving overall survival rates and response to treatment. For instance, trials utilizing checkpoint inhibitors in combination with standard chemotherapies have extended disease-free survival by up to 6 months compared to chemotherapy alone. Importantly, vaccines targeting specific tumor neoantigens have shown the potential to increase patient survival. However, these approaches also face significant challenges, including overcoming the immunosuppressive tumor microenvironment and enhancing the delivery and efficacy of therapeutic agents. By providing an overview of both the promising results and the obstacles encountered, this review aims to highlight ongoing efforts to refine immunotherapy approaches for better patient outcomes.

Enhancing pancreatic cancer immunotherapy: Leveraging localized delivery strategies through the use of implantable devices and scaffolds

Pancreatic cancer (PC) remains the predominant type of upper gastrointestinal tract cancer, associated with heightened morbidity and a survival rate below 12%. While immunotherapy has brought about transformative changes in the standards of care for most solid tumors, its application in PC is hindered by the ''cold tumor'' microenvironment, marked by the presence of immunosuppressive cells. Modest response rates in PC are attributed, in part to, the fibrotic stroma that obstructs the delivery of systemic immunotherapy. Furthermore, the occurrence of immune-related adverse events (iRAEs) often necessitates the use of sub-therapeutic doses or treatment discontinuation. In the pursuit of innovative approaches to enhance the effectiveness of immunotherapy for PC, implantable drug delivery devices and scaffolds emerge as promising strategies. These technologies offer the potential for sustained drug delivery directly to the tumor site, overcoming stromal barriers, immunosuppression, T cell exclusion, immunotherapy resistance, optimizing drug dosage, and mitigating systemic toxicity. This review offers a comprehensive exploration of pancreatic ductal adenocarcinoma (PDAC), the most common and aggressive form of PC, accompanied by a critical analysis of the challenges the microenvironment presents to the development of successful combinational immunotherapy approaches. Despite efforts, these approaches have thus far fallen short in enhancing treatment outcomes for PDAC. The review will subsequently delve into the imperative need for refining delivery strategies, providing an examination of past and ongoing studies in the field of localized immunotherapy for PDAC. Addressing these issues will lay the groundwork for the development of effective new therapies, thereby enhancing treatment response, patient survival, and overall quality of life for individuals diagnosed with PDAC.

Host-Gut Microbiota Metabolic Interactions and Their Role in Precision Diagnosis and Treatment of Gastrointestinal Cancers

The critical role of the gut microbiome in gastrointestinal cancers is becoming increasingly clear. Imbalances in the gut microbial community, referred to as dysbiosis, are linked to increased risks for various forms of gastrointestinal cancers. Pathogens like Fusobacterium and Helicobacter pylori relate to the onset of esophageal and gastric cancers, respectively, while microbes such as Porphyromonas gingivalis and Clostridium species have been associated with a higher risk of pancreatic cancer. In colorectal cancer, bacteria such as Fusobacterium nucleatum are known to stimulate the growth of tumor cells and trigger cancer-promoting pathways. On the other hand, beneficial microbes like Bifidobacteria offer a protective effect, potentially inhibiting the development of gastrointestinal cancers. The potential for therapeutic interventions that manipulate the gut microbiome is substantial, including strategies to engineer anti-tumor metabolites and employ microbiota-based treatments. Despite the progress in understanding the influence of the microbiome on gastrointestinal cancers, significant challenges remain in identifying and understanding the precise contributions of specific microbial species and their metabolic products. This knowledge is essential for leveraging the role of the gut microbiome in the development of precise diagnostics and targeted therapies for gastrointestinal cancers.

Driver mutation subtypes involve with differentiated immunophenotypes influencing pancreatic cancer outcomes

Despite many studies focusing on the prognostic biomarkers in pancreatic adenocarcinomas (PAADs), there is ill-informed about the relationships between their genomic features and immune characteristics. Herein, we deeply investigated the involvement of major driver mutation subtypes with immunophenotypes impacting PAAD outcomes. Based on public data analyses of RNA expression-based immune subtypes in PAAD, in contrast to KRAS G12D & TP53 co-mutant patients with poor outcomes, the best immune subtype C3 (inflammatory) characterized by high Th1/Th2 ratio was relatively enriched in KRASnon-G12DTP53wt patients with better survival, whereas the inferior subtype C2 (IFN-γ dominant) with low Th1/Th2 ratio was more common in the former than in the latter. Moreover, contrary to the highly immunosuppressive microenvironment (high Treg, high ratio of Treg to tumor-specific CD4+ T cell) in KRASG12DTP53mut patients, KRASG12VTP53wt individuals exhibited an inflamed context profiled by multiplex immunohistochemistry. It could be responsible for their outstanding survival advantage over others in postsurgical PAAD patients receiving adjuvant chemotherapy as shown by our cohort. Together, KRASG12VTP53wt may be a promising biomarker for prognostic evaluation and screening certain candidates with PAAD to get desirable survival benefit from adjuvant chemotherapy.

Development of an engineered extracellular vesicles-based vaccine platform for combined delivery of mRNA and protein to induce functional immunity

mRNA incorporated in lipid nanoparticles (LNPs) became a new class of vaccine modality for induction of immunity against COVID-19 and ushered in a new era in vaccine development. Here, we report a novel, easy-to-execute, and cost effective engineered extracellular vesicles (EVs)-based combined mRNA and protein vaccine platform (EVX-M+P vaccine) and explore its utility in proof-of-concept immunity studies in the settings of cancer and infectious disease. As a first example, we engineered EVs, natural nanoparticle carriers shed by all cells, to contain ovalbumin mRNA and protein (EVOvaM+P vaccine) to serve as cancer vaccine against ovalbumin-expressing melanoma tumors. EVOvaM+P administration to mice with established melanoma tumors resulted in tumor regression associated with effective humoral and adaptive immune responses. As a second example, we generated engineered EVs that contain Spike (S) mRNA and protein to serve as a combined mRNA and protein vaccine (EVSpikeM+P vaccine) against SARS-CoV-2 infection. EVSpikeM+P vaccine administration in mice and baboons elicited robust production of neutralizing IgG antibodies against RBD (receptor binding domain) of S protein and S protein specific T cell responses. Our proof-of-concept study describes a new platform with an ability for rapid development of combination mRNA and protein vaccines employing EVs for deployment against cancer and other diseases.

The tumor immune microenvironment in resected treatment-naive pancreatic cancer patients with long-term survival

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. Presently, only a fraction of patients undergo successful surgical resection, the most effective treatment. Enhancing treatment strategies necessitates a deep comprehension of the factors underlying extended survival after surgical resection in patients.

METHODS

This study aims to identify the important factors of PDAC patients' long-term survival with metatranscriptomics and multiplex immunofluorescence (IF) staining analyses. Specifically, differences in tumor immune microenvironment (TIME) were investigated between treatment-naïve PDAC short-term survivors (STS, overall survival <6 months) and long-term survivors (LTS, overall survival >5 years).

RESULTS

As a result, we detected 589 over-expressed genes, including HOXB9, CDA, and HOXB8, and 507 under-expressed genes, including AMY2B, SCARA5, and SLC2A2 in LTS. Most of the Reactome overbiological pathways enriched in our data were over-expressed in LTS, such as RHO GTPase Effectors and Cell Cycle Checkpoints. Eleven microbiomes significantly differed between LTS and STS, including Sphingopyxis and Capnocytophaga. Importantly, we demonstrate that the TIME profile with an increased abundance of memory B cells and the reduction of M0 and pro-tumoral M2 macrophages are associated with a good prognosis in PDAC.

CONCLUSIONS

In this study, we delved into the TIME with metatranscriptomics and IF staining analyses to understand the prerequisite of prolonged survival in PDAC patients. In LTS, several biological pathways were overexpressed, and specific microbiomes were identified. Furthermore, apparent differences in driven immune factors were found that provide valuable insights into developing new treatment strategies.

Inhibition of insulin-like growth factors increases production of CXCL9/10 by macrophages and fibroblasts and facilitates CD8+ cytotoxic T cell recruitment to pancreatic tumours

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with an urgent unmet clinical need for new therapies. Using a combination of in vitro assays and in vivo preclinical models we demonstrate that therapeutic inhibition of the IGF signalling axis promotes the accumulation of CD8+ cytotoxic T cells within the tumour microenvironment of PDAC tumours. Mechanistically, we show that IGF blockade promotes macrophage and fibroblast production of the chemokines CXCL9 and CXCL10 to facilitate CD8+ T cell recruitment and trafficking towards the PDAC tumour. Exploring this pathway further, we show that IGF inhibition leads to increased STAT1 transcriptional activity, correlating with a downregulation of the AKT/STAT3 signalling axis, in turn promoting Cxcl9 and Cxcl10 gene transcription. Using patient derived tumour explants, we also demonstrate that our findings translate into the human setting. PDAC tumours are frequently described as "immunologically cold", therefore bolstering CD8+ T cell recruitment to PDAC tumours through IGF inhibition may serve to improve the efficacy of immune checkpoint inhibitors which rely on the presence of CD8+ T cells in tumours.

MSH6 germline mutations leading to Lynch syndrome-associated cholangiocarcinoma: a case report

Lynch syndrome, a hereditary cancer susceptibility syndrome, arises from pathogenic mutations in mismatch repair genes. This syndrome is strongly linked to colorectal and endometrial cancers, as well as an elevated risk for other cancers such as gastric, ovarian, renal pelvis/ureter, and prostate. Notably, Lynch syndrome is rarely associated with cholangiocarcinoma (CCA). In this case study, we present a unique instance of Lynch syndrome-related CCA resulting from a singular MSH6 mutation. Notably, our findings reveal discrepancies between immunohistochemistry (IHC) and microsatellite stability results compared to genetic testing outcomes. This discrepancy underscores the limitations of solely relying on IHC analysis and microsatellite stability testing for the detection of hereditary tumors, emphasizing the crucial role of genetic testing in such cases. This insight enhances our comprehension of the mechanisms involved in cancer development and underscores the significance of thorough analysis integrating immunohistochemistry and genetic testing for diagnosing Lynch syndrome-related cancers.

Broadening oncological boundaries: the intratumoral microbiota

The microbiota of solid tumors was identified >100 years ago; however, heterogeneous composition and diversity have been revealed only recently. Growing evidence has suggested that several functional mechanisms of the intratumoral microbiota affect tumorigenesis and progression, suggesting that the intratumoral microbiota is a promising biomarker for multiple cancers. The low biomass of the intratumoral microbiota poses a major challenge to related research, thus necessitating the use of a multiple-modality integrated framework to resolve this dilemma. Advanced techniques such as single-cell sequencing provide significant clues, and the gradual optimization of functional experiments and culture-based methods enables deeper investigation of the underlying mechanisms involved. In this review, we outline the current state of research on the intratumoral microbiota and describe the challenges and comprehensive strategies for future research.

Computational Methods for Predicting Key Interactions in T Cell-Mediated Adaptive Immunity

The adaptive immune system recognizes pathogen- and cancer-specific features and is endowed with memory, enabling it to respond quickly and efficiently to repeated encounters with the same antigens. T cells play a central role in the adaptive immune system by directly targeting intracellular pathogens and helping to activate B cells to secrete antibodies. Several fundamental protein interactions-including those between major histocompatibility complex (MHC) proteins and antigen-derived peptides as well as between T cell receptors and peptide-MHC complexes-underlie the ability of T cells to recognize antigens with great precision. Computational approaches to predict these interactions are increasingly being used for medically relevant applications, including vaccine design and prediction of patient response to cancer immunotherapies. We provide computational researchers with an accessible introduction to the adaptive immune system, review computational approaches to predict the key protein interactions underlying T cell-mediated adaptive immunity, and highlight remaining challenges.

Stem-like T cells in cancer and autoimmunity

Stem-like T cells are characterized by their ability to self-renew, survive long-term, and give rise to a heterogeneous pool of effector and memory T cells. Recent advances in single-cell RNA-sequencing (scRNA-seq) and lineage tracing technologies revealed an important role for stem-like T cells in both autoimmunity and cancer. In cancer, stem-like T cells constitute an important arm of the anti-tumor immune response by giving rise to effector T cells that mediate tumor control. In contrast, in autoimmunity stem-like T cells perform an unfavorable role by forming a reservoir of long-lived autoreactive cells that replenish the pathogenic, effector T-cell pool and thereby driving disease pathology. This review provides background on the discovery of stem-like T cells and their function in cancer and autoimmunity. Moreover, the influence of the microbiota and metabolism on the stem-like T-cell pool is summarized. Lastly, the implications of our knowledge about stem-like T cells for clinical treatment strategies for cancer and autoimmunity will be discussed.

Harnessing microbial antigens as cancer antigens: a promising avenue for cancer immunotherapy

Immunotherapy has revolutionized cancer treatment by leveraging the immune system's innate capabilities to combat malignancies. Despite the promise of tumor antigens in stimulating anti-tumor immune responses, their clinical utility is hampered by limitations in eliciting robust and durable immune reactions, exacerbated by tumor heterogeneity and immune evasion mechanisms. Recent insights into the immunogenic properties of host homologous microbial antigens have sparked interest in their potential for augmenting anti-tumor immunity while minimizing off-target effects. This review explores the therapeutic potential of microbial antigen peptides in tumor immunotherapy, beginning with an overview of tumor antigens and their challenges in clinical translation. We further explore the intricate relationship between microorganisms and tumor development, elucidating the concept of molecular mimicry and its implications for immune recognition of tumor-associated antigens. Finally, we discuss methodologies for identifying and characterizing microbial antigen peptides, highlighting their immunogenicity and prospects for therapeutic application.

Peptide-stimulated T cells bypass immune checkpoint inhibitor resistance and eliminate autologous microsatellite instable colorectal cancer cells

Two hypermutated colon cancer cases with patient-derived cell lines, peripheral and tumor-infiltrating T cells available were selected for detailed investigation of immunological response.T cells co-cultured with autologous tumor cells showed only low levels of pro-inflammatory cytokines and failed at tumor recognition. Similarly, treatment of co-cultures with immune checkpoint inhibitors (ICI) did not boost antitumor immune responses. Since proteinase inhibitor 9 (PI-9) was detected in tumor cells, a specific inhibitor (PI-9i) was used in addition to ICI in T cell cytotoxicity testing. However, only pre-stimulation with tumor-specific peptides (cryptic and neoantigenic) significantly increased recognition and elimination of tumor cells by T cells independently of ICI or PI-9i.We showed, that ICI resistant tumor cells can be targeted by tumor-primed T cells and also demonstrated the superiority of tumor-naïve peripheral blood T cells compared to highly exhausted tumor-infiltrating T cells. Future precision immunotherapeutic approaches should include multimodal strategies to successfully induce durable anti-tumor immune responses.

Panoramic tumor microenvironment in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is notorious for its resistance to various treatment modalities. The genetic heterogeneity of PDAC, coupled with the presence of a desmoplastic stroma within the tumor microenvironment (TME), contributes to an unfavorable prognosis. The mechanisms and consequences of interactions among different cell types, along with spatial variations influencing cellular function, potentially play a role in the pathogenesis of PDAC. Understanding the diverse compositions of the TME and elucidating the functions of microscopic neighborhoods may contribute to understanding the immune microenvironment status in pancreatic cancer. As we delve into the spatial biology of the microscopic neighborhoods within the TME, aiding in deciphering the factors that orchestrate this intricate ecosystem. This overview delineates the fundamental constituents and the structural arrangement of the PDAC microenvironment, highlighting their impact on cancer cell biology.

RNA vaccines for cancer: Principles to practice

Vaccines are the most impactful medicines to improve health. Though potent against pathogens, vaccines for cancer remain an unfulfilled promise. However, recent advances in RNA technology coupled with scientific and clinical breakthroughs have spurred rapid discovery and potent delivery of tumor antigens at speed and scale, transforming cancer vaccines into a tantalizing prospect. Yet, despite being at a pivotal juncture, with several randomized clinical trials maturing in upcoming years, several critical questions remain: which antigens, tumors, platforms, and hosts can trigger potent immunity with clinical impact? Here, we address these questions with a principled framework of cancer vaccination from antigen detection to delivery. With this framework, we outline features of emergent RNA technology that enable rapid, robust, real-time vaccination with somatic mutation-derived neoantigens-an emerging "ideal" antigen class-and highlight latent features that have sparked the belief that RNA could realize the enduring vision for vaccines against cancer.

Combining CD40 agonist mitazalimab with mFOLFIRINOX in previously untreated metastatic pancreatic ductal adenocarcinoma (OPTIMIZE-1): a single-arm, multicentre phase 1b/2 study

BACKGROUND

Current systemic therapies for metastatic pancreatic ductal adenocarcinoma are associated with poor outcomes with a 5-year overall survival rate under 5%. We aimed to assess the safety and antitumour activity of mitazalimab, a human CD40 agonistic IgG1 antibody, with modified FOLFIRINOX (mFOLFIRINOX; fluorouracil, leucovorin, oxaliplatin, and irinotecan), in chemotherapy-naive patients with metastatic pancreatic ductal adenocarcinoma.

METHODS

OPTIMIZE-1 was a single-arm, multicentre, phase 1b/2 study which enrolled adults with histologically-confirmed metastatic pancreatic ductal adenocarcinoma and European Cooperative Oncology Group performance status 0 or 1 in 14 university hospitals in Belgium, France, and Spain. The primary endpoint of phase 1b was to determine the recommended phase 2 dose of intravenous mitazalimab (450 μg/kg or 900 μg/kg) when combined with intravenous mFOLFIRINOX (oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, irinotecan 150 mg/m2, fluorouracil 2400 mg/m2). In the first 21-day treatment cycle, mitazalimab was administered on days 1 and 10, and mFOLFIRINOX on day 8. In subsequent 14-day cycles mitazalimab was administered 2 days after mFOLFIRINOX. The phase 2 primary endpoint was objective response rate. Activity and safety analyses were conducted on the full analysis set (all patients who received the combination of mitazalimab at the recommended phase 2 dose and mFOLFIRINOX for at least two treatment cycles) and safety set (all patients who received any study treatment), respectively. Enrolment is complete, and data represents a primary analysis of the ongoing trial. The trial is registered at Clinicaltrials.gov (NCT04888312).

FINDINGS

Between Sept 29, 2021, and March 28, 2023, 88 patients were screened and 70 patients were enrolled (40 [57%] were female and 30 [43%] were male). In phase 1b, 900 μg/kg mitazalimab was determined as the recommended phase 2 dose. Overall, five patients received 450 μg/kg mitazalimab; 65 received 900 μg/kg mitazalimab. No dose-limiting toxicities were observed at 450 μg/kg, and one dose-limiting toxicity was observed at 900 μg/kg. 57 patients were evaluated for activity, and all 70 patients were included in the safety set. At data cutoff on Nov 14, 2023, median follow-up was 12·7 months (95% CI 11·1-15·7). Of the 57 patients, 29 (51%) remained on study and 18 (32%) remained on treatment. The primary endpoint (objective response rate >30%) was met (objective response rates in 23 [40%]; one-sided 90% CI ≥32 of 57 patients). The most common grade 3 or worse adverse events were neutropenia (18 [26%] of 70 patients), hypokalaemia (11 patients [16%]), and anaemia and thrombocytopenia (eight patients [11%]). Serious adverse events were reported in 29 (41%) of 70 patients, the most common being vomiting (five [7%] of 70 patients), decreased appetite (four [6%]), and diarrhoea and cholangitis (three [4%] of 70 patients for each), none considered related to mitazalimab. No treatment-related deaths were reported.

INTERPRETATION

Mitazalimab with mFOLFIRINOX demonstrated manageable safety and encouraging activity, warranting continued development in a phase 3, randomised, controlled trial. The results from OPTIMIZE-1 pave the way for further exploration and confirmation of a novel immunotherapy treatment regimen for metastatic pancreatic ductal adenocarcinoma, which is a complex and aggressive cancer with very low survival rates and restricted treatment options.

FUNDING

Alligator Bioscience.

Identification of pancreatic adenocarcinoma immune subtype associated with tumor neoantigen from aberrant alternative splicing

Background

Pancreatic adenocarcinoma (PAAD) is referred to as an immunologically "cold" tumor that responds poorly to immunotherapy. A fundamental theory that explains the low immunogenicity of PAAD is the dramatically low tumor mutation burden (TMB) of PAAD tumors, which fails to induce sufficient immune response. Alternative splicing of pre-mRNA, which could alter the proteomic diversity of many cancers, has been reported to be involved in neoantigen production. Therefore, we aim to identify novel PAAD antigens and immune subtypes through systematic bioinformatics research.

Methods

Data for splicing analysis were downloaded from The Cancer Genome Atlas (TCGA) SpliceSeq database. Among the available algorithms, we chose CIBERSORT to evaluate the immune cell distribution among PAADs. The TCGA-PAAD expression matrix was used to construct a co-expression network. Single-cell analysis was performed based on the Seurat workflow.

Results

Integrated analysis of aberrantly upregulated genes, alternatively spliced genes, genes associated with nonsense-mediated RNA decay (NMD) factors, antigen presentation and overall survival (OS) in TCGA-PAAD revealed that PLEC is a promising neoantigen for PAAD-targeted therapy. We identified a C2 TCGA-PAAD subtype that had better prognosis and more CD8+ T-cell infiltration. We propose a novel immune subtyping system for PAAD to indicate patient prognosis and opportunities for immunotherapy, such as immune checkpoint (ICP) inhibitors.

Conclusions

In conclusion, the present study used a transcriptome-guided approach to screen neoantigen candidates based on alternative splicing, NMD factors, and antigen-presenting signatures for PAAD. A prognosis model with guidance of immunotherapy will aid in patient selection for appropriate treatment.

Type I conventional dendritic cells facilitate immunotherapy in pancreatic cancer

Inflammation and tissue damage associated with pancreatitis can precede or occur concurrently with pancreatic ductal adenocarcinoma (PDAC). We demonstrate that in PDAC coupled with pancreatitis (ptPDAC), antigen-presenting type I conventional dendritic cells (cDC1s) are specifically activated. Immune checkpoint blockade therapy (iCBT) leads to cytotoxic CD8+ T cell activation and elimination of ptPDAC with restoration of life span even upon PDAC rechallenge. Using PDAC antigen-loaded cDC1s as a vaccine, immunotherapy-resistant PDAC was rendered sensitive to iCBT with elimination of tumors. cDC1 vaccination coupled with iCBT identified specific CDR3 sequences in the tumor-infiltrating CD8+ T cells with potential therapeutic importance. This study identifies a fundamental difference in the immune microenvironment in PDAC concurrent with, or without, pancreatitis and provides a rationale for combining cDC1 vaccination with iCBT as a potential treatment option.

Unveiling the intratumoral microbiota within cancer landscapes

Recent advances in cancer research have unveiled a significant yet previously underappreciated aspect of oncology: the presence and role of intratumoral microbiota. These microbial residents, encompassing bacteria, fungi, and viruses within tumor tissues, have been found to exert considerable influence on tumor development, progression, and the efficacy of therapeutic interventions. This review aims to synthesize these groundbreaking discoveries, providing an integrated overview of the identification, characterization, and functional roles of intratumoral microbiota in cancer biology. We focus on elucidating the complex interactions between these microorganisms and the tumor microenvironment, highlighting their potential as novel biomarkers and therapeutic targets. The purpose of this review is to offer a comprehensive understanding of the microbial dimension in cancer, paving the way for innovative approaches in cancer diagnosis and treatment.

Exploring prognostic and immunological characteristics of pancreatic ductal adenocarcinoma through comprehensive genomic analysis of tertiary lymphoid structures and CD8 + T-cells

PURPOSE

Tertiary lymphoid structures (TLSs) and CD8 + T-cells are potential prognostic indicators for pancreatic ductal adenocarcinoma (PDAC). We established a novel scoring system for evaluating the risk for PDAC based on TLS- and CD8 + T-cell-related genes.

METHODS

We analyzed single-cell sequence data from PDAC patients in the Genome Sequence Archive. Bioinformatics and machine algorithms established and validated a scoring method (T-C score) based on PDAC survival-related genes highly expressed in TLSs and CD8 + T-cells. Patients were stratified into the low- and high-T-C score groups. Differences in survival, pathway enrichment, mutation status, immune cell infiltration, expression of immune checkpoint-associated genes, tumor stemness, and response to antitumor therapy were compared through computer simulation methods.

RESULTS

Overall survival differed significantly between the training and validation cohorts' low- and high-T-C score groups. The low-T-C score group correlated with lower tumor mutation burden and lower levels of tumor stemness compared with the high-T-C score group. Patients with lower T-C scores exhibited advantages in immunotherapeutic responses and might be more sensitive to the chemotherapeutic regimen and multi-kinase inhibitors.

CONCLUSION

The T-C score could serve as an effective model for predicting the survival and therapeutic responses of patients with PDAC.

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

Phase I Trial of Viral Vector-Based Personalized Vaccination Elicits Robust Neoantigen-Specific Antitumor T-Cell Responses

PURPOSE

Personalized vaccines targeting multiple neoantigens (nAgs) are a promising strategy for eliciting a diversified antitumor T-cell response to overcome tumor heterogeneity. NOUS-PEV is a vector-based personalized vaccine, expressing 60 nAgs and consists of priming with a nonhuman Great Ape Adenoviral vector (GAd20) followed by boosts with Modified Vaccinia Ankara. Here, we report data of a phase Ib trial of NOUS-PEV in combination with pembrolizumab in treatment-naïve patients with metastatic melanoma (NCT04990479).

PATIENTS AND METHODS

The feasibility of this approach was demonstrated by producing, releasing, and administering to 6 patients 11 of 12 vaccines within 8 weeks from biopsy collection to GAd20 administration.

RESULTS

The regimen was safe, with no treatment-related serious adverse events observed and mild vaccine-related reactions. Vaccine immunogenicity was demonstrated in all evaluable patients receiving the prime/boost regimen, with detection of robust neoantigen-specific immune responses to multiple neoantigens comprising both CD4 and CD8 T cells. Expansion and diversification of vaccine-induced T-cell receptor (TCR) clonotypes was observed in the posttreatment biopsies of patients with clinical response, providing evidence of tumor infiltration by vaccine-induced neoantigen-specific T cells.

CONCLUSIONS

These findings indicate the ability of NOUS-PEV to amplify and broaden the repertoire of tumor-reactive T cells to empower a diverse, potent, and durable antitumor immune response. Finally, a gene signature indicative of the reduced presence of activated T cells together with very poor expression of the antigen-processing machinery genes has been identified in pretreatment biopsies as a potential biomarker of resistance to the treatment.

Advances in Surgery and (Neo) Adjuvant Therapy in the Management of Pancreatic Cancer

A multimodality approach, which usually includes chemotherapy, surgery, and/or radiotherapy, is optimal for patients with localized pancreatic cancer. The timing and sequence of these interventions depend on anatomic resectability and the biological suitability of the tumor and the patient. Tumors with vascular involvement (ie, borderline resectable/locally advanced) require surgical reassessments after therapy and participation of surgeons familiar with advanced techniques. When indicated, venous reconstruction should be offered as standard of care because it has acceptable morbidity. Morbidity and mortality of pancreas surgery may be mitigated when surgery is performed at high-volume centers.

Intratumoral Cell Neighborhoods Coordinate Outcomes in Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

Pancreatic ductal adenocarcinoma (PDA) is a highly lethal disease characterized by a spatially heterogeneous tumor microenvironment. Within the PDA microenvironment, cells organize into communities where cell fate is influenced by neighboring cells of diverse ontogeny and function. However, it remains unclear how cell neighborhoods in the tumor microenvironment evolve with treatment and impact clinical outcomes.

METHODS

Here, using automated chromogenic multiplex immunohistochemistry and unsupervised computational image analysis of human PDA tumors, we investigated cell neighborhoods in surgically resected tumors from patients with chemotherapy-naïve PDA (n = 59) and neoadjuvant chemotherapy-treated PDA (n = 57). Single cells were defined by lineage markers (CD3, CD8, Foxp3, CD68, CK19), proliferation (Ki67), and neighboring cells.

RESULTS

Distinct intratumoral immune and tumor cell subsets were defined by neighboring cells. Higher content of stromal-associated macrophages was seen in chemotherapy-naïve tumors from long-term survivors (overall survival >3 years) compared with short-term survivors (overall survival <1 year), whereas immune-excluded tumor cells were higher in short-term survivors. Chemotherapy-treated vs -naïve tumors showed lower content of tumor-associated T cells and macrophages but similar densities of stromal-associated immune cells. However, proliferating tumor cell subsets with immune-rich neighborhoods were higher in chemotherapy-treated tumors. In a blinded analysis of tumors from patients treated with neoadjuvant chemotherapy, a composite index comprising lower quantities of immune-excluded tumor cells and higher spatially distinct immune cell subsets was associated with prolonged survival.

CONCLUSIONS

Together, these data provide new insights into discrete cell communities in PDA and show their clinical relevance.

Targeting Neoantigens in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and is currently the third leading cause of cancer-related death in the United States after lung and colon cancer. PDAC is estimated to be the second leading cause of cancer-related death by 2030. The diagnosis at a late stage is the underlying cause for higher mortality and poor prognosis after surgery. Treatment resistance to chemotherapy and immunotherapy results in recurrence after surgery and poor prognosis. Neoantigen burden and CD8+ T-cell infiltration are associated with clinical outcomes in PDAC and paucity of neoantigen-reactive tumor-infiltrating lymphocytes may be the underlying cause for treatment resistance for immunotherapy. This suggests a need to identify additional neoantigens and therapies targeting these neoantigens to improve clinical outcomes in PDAC. In this review, we focus on describing the pathophysiology, current treatment strategies, and treatment resistance in PDAC followed by the need to target neoantigens in PDAC.

Manipulating regulatory T cells: is it the key to unlocking effective immunotherapy for pancreatic ductal adenocarcinoma?

The five-year survival rates for pancreatic ductal adenocarcinoma (PDAC) have scarcely improved over the last half-century. It is inherently resistant to FDA-approved immunotherapies, which have transformed the outlook for patients with other advanced solid tumours. Accumulating evidence relates this resistance to its hallmark immunosuppressive milieu, which instils progressive dysfunction among tumour-infiltrating effector T cells. This milieu is established at the inception of neoplasia by immunosuppressive cellular populations, including regulatory T cells (Tregs), which accumulate in parallel with the progression to malignant PDAC. Thus, the therapeutic manipulation of Tregs has captured significant scientific and commercial attention, bolstered by the discovery that an abundance of tumour-infiltrating Tregs correlates with a poor prognosis in PDAC patients. Herein, we propose a mechanism for the resistance of PDAC to anti-PD-1 and CTLA-4 immunotherapies and re-assess the rationale for pursuing Treg-targeted therapies in light of recent studies that profiled the immune landscape of patient-derived tumour samples. We evaluate strategies that are emerging to limit Treg-mediated immunosuppression for the treatment of PDAC, and signpost early-stage trials that provide preliminary evidence of clinical activity. In this context, we find a compelling argument for investment in the ongoing development of Treg-targeted immunotherapies for PDAC.

Prediction of tumor-specific splicing from somatic mutations as a source of neoantigen candidates

Motivation

Neoantigens are promising targets for cancer immunotherapies and might arise from alternative splicing. However, detecting tumor-specific splicing is challenging because many non-canonical splice junctions identified in tumors also appear in healthy tissues. To increase tumor-specificity, we focused on splicing caused by somatic mutations as a source for neoantigen candidates in individual patients.

Results

We developed the tool splice2neo with multiple functionalities to integrate predicted splice effects from somatic mutations with splice junctions detected in tumor RNA-seq and to annotate the resulting transcript and peptide sequences. Additionally, we provide the tool EasyQuant for targeted RNA-seq read mapping to candidate splice junctions. Using a stringent detection rule, we predicted 1.7 splice junctions per patient as splice targets with a false discovery rate below 5% in a melanoma cohort. We confirmed tumor-specificity using independent, healthy tissue samples. Furthermore, using tumor-derived RNA, we confirmed individual exon-skipping events experimentally. Most target splice junctions encoded neoepitope candidates with predicted major histocompatibility complex (MHC)-I or MHC-II binding. Compared to neoepitope candidates from non-synonymous point mutations, the splicing-derived MHC-I neoepitope candidates had lower self-similarity to corresponding wild-type peptides. In conclusion, we demonstrate that identifying mutation-derived, tumor-specific splice junctions can lead to additional neoantigen candidates to expand the target repertoire for cancer immunotherapies.

Availability and implementation

The R package splice2neo and the python package EasyQuant are available at https://github.com/TRON-Bioinformatics/splice2neo and https://github.com/TRON-Bioinformatics/easyquant, respectively.

HHLA2 deficiency inhibits pancreatic cancer progression and THP-1 macrophage M2 polarization via EGFR/MAPK/ERK and mTOR/AKT pathway

BACKGROUND

Human endogenous retrovirus subfamily H long terminal repeat associating protein 2, (HHLA2), a member of B7 family, exhibits heightened expression in various malignant tumors. However, the exact functions of HHLA2 in pancreatic cancer (PC) remain incompletely elucidated.

METHODS

We initially conducted an analysis of the B7 family members' expression pattern in pancreatic tumor samples and adjacent normal tissues using The Cancer Genome Atlas (TCGA) database. Subsequently, immunohistochemistry, RT-qPCR and western blot methods were used to assess HHLA2 expression levels in PC tissues and cell lines. Furthermore, after silencing HHLA2 in PC cell lines, cell migration and proliferation of PC cells were detected by wound healing and CCK-8 assays, and cell invasion of PC cells was detected by transwell assays. We also investigated the regulation of epithelial-mesenchymal transition (EMT) markers and levels of EGFR, MEK, ERK1/2, mTOR and AKT via western blot analysis. Finally, the correlation between HHLA2 expression and immune infiltration was further explored.

RESULTS

Silencing of HHLA2 resulted in the inhibition of PC cell proliferation, migration and invasion, potentially through the suppression of the EGFR/MAPK/ERK and mTOR/AKT signaling pathway. Additionally, silencing HHLA2 led to the inhibition of M2-type polarization of tumor associated macrophages (TAMs).

CONCLUSION

The knockdown of HHLA2 was observed to inhibit the migration and invasion of PC cells through the regulation of the EMT process and EGFR/MAPK/ERK and mTOR/AKT pathway. Furthermore, silencing HHLA2 was found to modulate M2 polarization of TAMs. These finding suggest that HHLA2 could be a promising therapeutic target for Pancreatic cancer.

MUC16: clinical targets with great potential

Mucin 16 (MUC16) is a membrane-bound mucin that is abnormally expressed or mutated in a variety of diseases, especially tumors, while being expressed in normal body epithelium. MUC16 and its extracellular components are often important cancer-related biomarkers. Abnormal expression of MUC16 promotes tumor progression through mesenchymal protein, PI3K/AKT pathway, JAK2/STAT3 pathway, ERK/FBW7/c-Myc, and other mechanisms, and plays an important role in the occurrence and development of tumors. In addition, MUC16 also helps tumor immune escape by inhibiting T cells and NK cells. Many drugs and trials targeting MUC16 have been developed, and MUC16 may be a new direction for future treatments. In this paper, the mechanism of action of MUC16 in the development of cancer, especially in the immune escape of tumor, is introduced in detail, indicating the potential of MUC16 in clinical treatment.

Cellular collusion: cracking the code of immunosuppression and chemo resistance in PDAC

Despite the efforts, pancreatic ductal adenocarcinoma (PDAC) is still highly lethal. Therapeutic challenges reside in late diagnosis and establishment of peculiar tumor microenvironment (TME) supporting tumor outgrowth. This stromal landscape is highly heterogeneous between patients and even in the same patient. The organization of functional sub-TME with different cellular compositions provides evolutive advantages and sustains therapeutic resistance. Tumor progressively establishes a TME that can suit its own needs, including proliferation, stemness and invasion. Cancer-associated fibroblasts and immune cells, the main non-neoplastic cellular TME components, follow soluble factors-mediated neoplastic instructions and synergize to promote chemoresistance and immune surveillance destruction. Unveiling heterotypic stromal-neoplastic interactions is thus pivotal to breaking this synergism and promoting the reprogramming of the TME toward an anti-tumor milieu, improving thus the efficacy of conventional and immune-based therapies. We underscore recent advances in the characterization of immune and fibroblast stromal components supporting or dampening pancreatic cancer progression, as well as novel multi-omic technologies improving the current knowledge of PDAC biology. Finally, we put into context how the clinic will translate the acquired knowledge to design new-generation clinical trials with the final aim of improving the outcome of PDAC patients.

Metal-Organic Framework-Based Nanovaccine for Relieving Immunosuppressive Tumors via Hindering Efferocytosis of Macrophages and Promoting Pyroptosis and Cuproptosis of Cancer Cells

Current cancer vaccines face challenges due to an immunosuppressive tumor microenvironment and their limited ability to produce an effective immune response. To address the above limitations, we develop a 3-(2-spiroadamantyl)-4-methoxy-4-(3-phosphoryloxy)-phenyl-1,2-dioxetane (alkaline phosphatase substrate) and XMD8-92 (extracellular signal-regulated kinase 5 inhibitor)-codelivered copper-tetrahydroxybenzoquinone (Cu-THBQ/AX) nanosized metal-organic framework to in situ-generate therapeutic vaccination. Once inside the early endosome, the alkaline phosphatase overexpressed in the tumor cells' membrane activates the in situ type I photodynamic effect of Cu-THBQ/AX for generating •O2-, and the Cu-THBQ/AX catalyzes O2 and H2O2 to •O2- and •OH via semiquinone radical catalysis and Fenton-like reactions. This surge of ROS in early endosomes triggers caspase-3-mediated proinflammatory pyroptosis via activating phospholipase C. Meanwhile, Cu-THBQ/AX can also induce the oligomerization of dihydrolipoamide S-acetyltransferase to trigger tumor cell cuproptosis. The production of •OH could also trigger the release of XMD8-92 for effectively inhibiting the efferocytosis of macrophages to convert immunosuppressive apoptosis of cancer cells into proinflammatory secondary necrosis. The simultaneous induction of pyroptosis, cuproptosis, and secondary necrosis effectively converts the tumor microenvironment from "cold" to "hot" conditions, making it an effective antigen pool. This transformation successfully activates the antitumor immune response, inhibiting tumor growth and metastasis.

Blockade of histamine receptor H1 augments immune checkpoint therapy by enhancing MHC-I expression in pancreatic cancer cells

BACKGROUND

Although immune checkpoint blockade (ICB) therapy has proven to be extremely effective at managing certain cancers, its efficacy in treating pancreatic ductal adenocarcinoma (PDAC) has been limited. Therefore, enhancing the effect of ICB could improve the prognosis of PDAC. In this study, we focused on the histamine receptor H1 (HRH1) and investigated its impact on ICB therapy for PDAC.

METHODS

We assessed HRH1 expression in pancreatic cancer cell (PCC) specimens from PDAC patients through public data analysis and immunohistochemical (IHC) staining. The impact of HRH1 in PCCs was evaluated using HRH1 antagonists and small hairpin RNA (shRNA). Techniques including Western blot, flow cytometry, quantitative reverse transcription polymerase chain reaction (RT-PCR), and microarray analyses were performed to identify the relationships between HRH1 and major histocompatibility complex class I (MHC-I) expression in cancer cells. We combined HRH1 antagonism or knockdown with anti-programmed death receptor 1 (αPD-1) therapy in orthotopic models, employing IHC, immunofluorescence, and hematoxylin and eosin staining for assessment.

RESULTS

HRH1 expression in cancer cells was negatively correlated with HLA-ABC expression, CD8+ T cells, and cytotoxic CD8+ T cells. Our findings indicate that HRH1 blockade upregulates MHC-I expression in PCCs via cholesterol biosynthesis signaling. In the orthotopic model, the combined inhibition of HRH1 and αPD-1 blockade enhanced cytotoxic CD8+ T cell penetration and efficacy, overcoming resistance to ICB therapy.

CONCLUSIONS

HRH1 plays an immunosuppressive role in cancer cells. Consequently, HRH1 intervention may be a promising method to amplify the responsiveness of PDAC to immunotherapy.

Antibiotic use reduces the efficacy of immune checkpoint inhibitors in patients with urothelial carcinoma: A systematic review and meta-analysis

CONTEXT

Antibiotics have been suggested to diminish the efficacy of immune checkpoint inhibitors (ICIs) by alterations of the gut microbiota.

OBJECTIVE

To perform a meta-analysis summarizing the effect of antibiotics on the overall survival (OS) and progression-free survival (PFS) of urothelial cancer (UC) patients receiving ICI.

EVIDENCE ACQUISITION

PubMed, EMBASE (Ovid), and the Cochrane Library were searched to identify studies published up to July 14, 2023. Studies reporting the associations between antibiotics use and OS and PFS in UC patients treated with ICI were included in this systematic review and meta-analysis. The random-effect model was used to pool the Hazard Ratios (HRs) for OS and PFS with 95% confidence interval (95%CI). The ROBINS-I was used to assess the risk of bias in the included studies, while the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was used to inform the quality of evidence.

EVIDENCE SYNTHESIS

Thirteen nonrandomized studies involving a total of 5,095 ICI-treated UC patients were included in this review, of which 1434 (28%) received antibiotics. Overall, compared to patients who did not receive antibiotics, the pooled HRs for OS and PFS in those who received antibiotics were 1.45 [95% CI 1.25-1.68] and 1.40 [95% CI 1.05-1.87], respectively. Subgroup analysis revealed that the types of ICI and timing of antibiotic initiation did not influence the effect of antibiotics on OS and PFS in UC patients (P > 0.05).

CONCLUSIONS

Antibiotic use significantly reduced OS and PFS in UC patients receiving ICI. While antibiotics remain crucial for the treatment of infections in UC patients, antibiotics should be prescribed cautiously in UC patients receiving ICI.

PATIENT SUMMARY

Antibiotic use is associated with worsened survival in UC patients receiving immune checkpoint inhibitors.

Hepatocytes coordinate immune evasion in cancer via release of serum amyloid A proteins

T cell infiltration into tumors is a favorable prognostic feature, but most solid tumors lack productive T cell responses. Mechanisms that coordinate T cell exclusion are incompletely understood. Here we identify hepatocyte activation via interleukin-6/STAT3 and secretion of serum amyloid A (SAA) proteins 1 and 2 as important regulators of T cell surveillance of extrahepatic tumors. Loss of STAT3 in hepatocytes or SAA remodeled the tumor microenvironment with infiltration by CD8+ T cells, while interleukin-6 overexpression in hepatocytes and SAA signaling via Toll-like receptor 2 reduced the number of intratumoral dendritic cells and, in doing so, inhibited T cell tumor infiltration. Genetic ablation of SAA enhanced survival after tumor resection in a T cell-dependent manner. Likewise, in individuals with pancreatic ductal adenocarcinoma, long-term survivors after surgery demonstrated lower serum SAA levels than short-term survivors. Taken together, these data define a fundamental link between liver and tumor immunobiology wherein hepatocytes govern productive T cell surveillance in cancer.

Tumor Antigens beyond the Human Exome

With the advent of immunotherapeutics, a new era in the combat against cancer has begun. Particularly promising are neo-epitope-targeted therapies as the expression of neo-antigens is tumor-specific. In turn, this allows the selective targeting and killing of cancer cells whilst healthy cells remain largely unaffected. So far, many advances have been made in the development of treatment options which are tailored to the individual neo-epitope repertoire. The next big step is the achievement of efficacious "off-the-shelf" immunotherapies. For this, shared neo-epitopes propose an optimal target. Given the tremendous potential, a thorough understanding of the underlying mechanisms which lead to the formation of neo-antigens is of fundamental importance. Here, we review the various processes which result in the formation of neo-epitopes. Broadly, the origin of neo-epitopes can be categorized into three groups: canonical, noncanonical, and viral neo-epitopes. For the canonical neo-antigens that arise in direct consequence of somatic mutations, we summarize past and recent findings. Beyond that, our main focus is put on the discussion of noncanonical and viral neo-epitopes as we believe that targeting those provides an encouraging perspective to shape the future of cancer immunotherapeutics.

Microphysiological systems as models for immunologically 'cold' tumors

The tumor microenvironment (TME) is a diverse milieu of cells including cancerous and non-cancerous cells such as fibroblasts, pericytes, endothelial cells and immune cells. The intricate cellular interactions within the TME hold a central role in shaping the dynamics of cancer progression, influencing pivotal aspects such as tumor initiation, growth, invasion, response to therapeutic interventions, and the emergence of drug resistance. In immunologically 'cold' tumors, the TME is marked by a scarcity of infiltrating immune cells, limited antigen presentation in the absence of potent immune-stimulating signals, and an abundance of immunosuppressive factors. While strategies targeting the TME as a therapeutic avenue in 'cold' tumors have emerged, there is a pressing need for novel approaches that faithfully replicate the complex cellular and non-cellular interactions in order to develop targeted therapies that can effectively stimulate immune responses and improve therapeutic outcomes in patients. Microfluidic devices offer distinct advantages over traditional in vitro 3D co-culture models and in vivo animal models, as they better recapitulate key characteristics of the TME and allow for precise, controlled insights into the dynamic interplay between various immune, stromal and cancerous cell types at any timepoint. This review aims to underscore the pivotal role of microfluidic systems in advancing our understanding of the TME and presents current microfluidic model systems that aim to dissect tumor-stromal, tumor-immune and immune-stromal cellular interactions in various 'cold' tumors. Understanding the intricacies of the TME in 'cold' tumors is crucial for devising effective targeted therapies to reinvigorate immune responses and overcome the challenges of current immunotherapy approaches.

Second-Line Treatment of Pancreatic Adenocarcinoma: Shedding Light on New Opportunities and Key Talking Points from Clinical Trials

Despite improvements in overall cancer mortality, deaths related to pancreatic cancer continue to rise. Following first-line treatment, second-line options are significantly limited. Classically, first-line treatment consisted of either gemcitabine or 5-fluorouracil based systemic chemotherapy. Upon progression of disease or recurrence, subsequent second-line treatment is still gemcitabine or 5-fluorouracil based chemotherapy, depending on what was used in the first line and the timing of progression or recurrence. A better understanding of the molecular underpinnings of pancreatic adenocarcinoma (PDAC) has led to new treatment strategies including specifically targeting the desmoplastic stroma, cytokine signaling and actionable mutations. Furthermore, efforts are also directed to enhance the immunogenicity profile of PDAC's well-established immunologically "cold" tumor microenvironment. More recently, the outstanding response rates of chimeric antigen receptor T (CAR-T) cells in hematologic malignancies, have led to clinical trials to evaluate the treatment modality in PDAC. In this review, we summarize recently presented clinical trials for metastatic pancreatic adenocarcinoma with novel treatment approaches in the second line and beyond.

The mechanism of USP43 in the development of tumor: a literature review

Ubiquitination of the proteins is crucial for governing protein degradation and regulating fundamental cellular processes. Deubiquitinases (DUBs) have emerged as significant regulators of multiple pathways associated with cancer and other diseases, owing to their capacity to remove ubiquitin from target substrates and modulate signaling. Consequently, they represent potential therapeutic targets for cancer and other life-threatening conditions. USP43 belongs to the DUBs family involved in cancer development and progression. This review aims to provide a comprehensive overview of the existing scientific evidence implicating USP43 in cancer development. Additionally, it will investigate potential small-molecule inhibitors that target DUBs that may have the capability to function as anti-cancer medicines.

Novel insights into TCR-T cell therapy in solid neoplasms: optimizing adoptive immunotherapy

Adoptive immunotherapy in the T cell landscape exhibits efficacy in cancer treatment. Over the past few decades, genetically modified T cells, particularly chimeric antigen receptor T cells, have enabled remarkable strides in the treatment of hematological malignancies. Besides, extensive exploration of multiple antigens for the treatment of solid tumors has led to clinical interest in the potential of T cells expressing the engineered T cell receptor (TCR). TCR-T cells possess the capacity to recognize intracellular antigen families and maintain the intrinsic properties of TCRs in terms of affinity to target epitopes and signal transduction. Recent research has provided critical insight into their capability and therapeutic targets for multiple refractory solid tumors, but also exposes some challenges for durable efficacy. In this review, we describe the screening and identification of available tumor antigens, and the acquisition and optimization of TCRs for TCR-T cell therapy. Furthermore, we summarize the complete flow from  laboratory to clinical applications of TCR-T cells. Last, we emerge future prospects for improving therapeutic efficacy in cancer world with combination therapies or TCR-T derived products. In conclusion, this review depicts our current understanding of TCR-T cell therapy in solid neoplasms, and provides new perspectives for expanding its clinical applications and improving therapeutic efficacy.

Tumor-resident microbes: the new kids on the microenvironment block

Tumor-resident microbes (TRM) are an integral component of the tumor microenvironment (TME). TRM can influence tumor growth, distant dissemination, and response to therapies by interfering with molecular pathways in tumor cells as well as with other components of the TME. Novel technologies are improving the identification and visualization of cell type-specific microbes in the TME. The mechanisms that mediate the role of TRM at the primary tumors and metastatic sites are being elucidated. This knowledge is providing novel perspectives for targeting microbes or using microbial interventions for cancer interception or therapy.

Emerging potential of immunopeptidomics by mass spectrometry in cancer immunotherapy

With significant advances in analytical technologies, research in the field of cancer immunotherapy, such as adoptive T cell therapy, cancer vaccine, and immune checkpoint blockade (ICB), is currently gaining tremendous momentum. Since the efficacy of cancer immunotherapy is recognized only by a minority of patients, more potent tumor-specific antigens (TSAs, also known as neoantigens) and predictive markers for treatment response are of great interest. In cancer immunity, immunopeptides, presented by human leukocyte antigen (HLA) class I, play a role as initiating mediators of immunogenicity. The latest advancement in the interdisciplinary multiomics approach has rapidly enlightened us about the identity of the "dark matter" of cancer and the associated immunopeptides. In this field, mass spectrometry (MS) is a viable option to select because of the naturally processed and actually presented TSA candidates in order to grasp the whole picture of the immunopeptidome. In the past few years the search space has been enlarged by the multiomics approach, the sensitivity of mass spectrometers has been improved, and deep/machine-learning-supported peptide search algorithms have taken immunopeptidomics to the next level. In this review, along with the introduction of key technical advancements in immunopeptidomics, the potential and further directions of immunopeptidomics will be reviewed from the perspective of cancer immunotherapy.

Characterizing and forecasting neoantigens-resulting from MUC mutations in COAD

BACKGROUND

The treatment for colon adenocarcinoma (COAD) faces challenges in terms of immunotherapy effectiveness due to multiple factors. Because of the high tumor specificity and immunogenicity, neoantigen has been considered a pivotal target for cancer immunotherapy. Therefore, this study aims to identify and predict the potential tumor antigens of MUC somatic mutations (MUCmut) in COAD.

METHODS

Three databases of TCGA, TIMER2.0, and cBioPortal were used for a detailed evaluation of the association between MUCmut and multi-factors like tumor mutation burden (TMB), microsatellite instability (MSI), prognosis, and the tumor microenvironment within the context of total 2242 COAD patients. Next, TSNAdb and the differential agretopicity index (DAI) were utilized to predict high-confidence neopeptides for MUCmut based on 531 COAD patients' genomic information. DAI was calculated by subtraction of its predicted HLA binding affinity of the MUCmut peptide from the corresponding wild-type peptide.

RESULTS

The top six mutation frequencies (14 to 2.9%) were from MUC16, MUC17, MUC5B, MUC2, MUC4 and MUC6. COAD patients with MUC16 and MUC4 mutations had longer DFS and PFS. However, patients with MUC13 and MUC20 mutations had shorter OS. Patients with the mutation of MUC16, MUC5B, MUC2, MUC4, and MUC6 exhibited higher TMB and MSI. Moreover, these mutations from the MUC family were associated with the infiltration of diverse lymphocyte cells and the expression of immune checkpoint genes. Through TSNAdb 1.0/NetMHCpan v2.8, 452 single nucleotide variants (SNVs) of MUCmut peptides were identified. Moreover, through TSNAdb2.0/NetMHCpan v4.0, 57 SNVs, 1 Q-frame shift (TS), and 157 short insertions/deletions (INDELs) of MUCmut were identified. Finally, 10 high-confidence neopeptides of MUCmut were predicted by DAI.

CONCLUSIONS

Together, our findings establish the immunogenicity and therapeutic potential of mutant MUC family-derived neoantigens. Through combining the tools of TSNAdb and DAI, a group of novel MUCmut neoantigens were identified as potential targets for immunotherapy.