In human beings heterogenous, pervasive and lethal malignancies of different parts of the gastrointestinal (GI) tract viz., tumours of the oesophagus, stomach, small intestine, colon, and rectum, represent gastrointestinal malignancies. Primary treatment modality for gastric cancer includes chemotherapy, surgical interventions, radiotherapy, monoclonal antibodies and inhibitors of angiogenesis. However, there is a need to improve upon the existing treatment modality due to associated adverse events and the development of resistance towards treatment. Additionally, age has been found to contribute to increasing the incidence of tumours due to immunosenescence-associated immunosuppression. Immunosenescence is the natural process of ageing, wherein immune cells as well as organs begin to deteriorate resulting in a dysfunctional or malfunctioning immune system. Accretion of senescent cells in immunosenescence results in the creation of a persistent inflammatory environment or inflammaging, marked with elevated expression of pro-inflammatory and immunosuppressive cytokines and chemokines. Perturbation in the T-cell pools and persistent stimulation by the antigens facilitate premature senility of the immune cells, and senile immune cells exacerbate inflammaging conditions and the inefficiency of the immune system to identify the tumour antigen. Collectively, these conditions contribute positively towards tumour generation, growth and eventually proliferation. Thus, activating the immune cells to distinguish the tumour cells from normal cells and invade them seems to be a logical strategy for the treatment of cancer. Consequently, various approaches to immunotherapy, viz., programmed death ligand-1 (PD-1) inhibitors, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors etc are being extensively evaluated for their efficiency in gastric cancer. In fact, PD-1 inhibitors have been sanctioned as late late-line therapy modality for gastric cancer. The present review will focus on deciphering the link between the immune system and gastric cancer, and the alterations in the immune system that incur during the development of gastrointestinal malignancies. Also, the mechanism of evasion by tumour cells and immune checkpoints involved along with different approaches of immunotherapy being evaluated in different clinical trials will be discussed.

N6-methyladenosine (m6A) RNA methylation is crucially involved in the genesis and advancement of gastric cancer (GC) by controlling various pathobiological aspects including gene expression, signal transduction, metabolism, cell death, epithelial-mesenchymal transition, angiogenesis, and exosome function. Despite its importance, the exact mechanisms by which m6A modification influences GC biology remain inadequately explored. This review consolidates the latest advances in uncovering the mechanisms and diverse roles of m6A in GC and proposes new research and translational directions. Key regulators (writers, readers, and erasers) of m6A, such as METTL3/14/16 and WTAP, significantly affect cancer progression, anticancer immune response, and treatment outcomes. m6A modification also impacts immune cell infiltration and the tumor microenvironment, highlighting its potential as a diagnostic and prognostic marker. Interactions between m6A methylation and non-coding RNAs offer further novel insights into GC development and therapeutic targets. Targeting m6A regulators could enhance immunotherapy response, overcome treatment resistance, and improve oncological and clinical outcomes. Models based on m6A can precisely predict treatment response and prognosis in GC. Additional investigation is needed to fully understand the mechanisms of m6A methylation and its potential clinical applications and relevance (e.g., as precise markers for early detection, prediction of outcome, and response to therapy and as therapeutic targets) in GC. Future research should focus on in vivo studies, potential clinical trials, and the examination of m6A modification in other types of cancers.

Although immune checkpoint inhibitors show great promise, not all patients respond and many do not achieve durable responses. Consequently, further investigations into potentially targetable molecules that regulate immune checkpoints are warranted. Previous studies in several cancers demonstrated that interferons produced by tumor-infiltrating leukocytes regulate immunosuppressive PD-L1, PD-L2 and IDO1 through JAK/STAT signaling. Here, we investigated a novel role for an immunosuppressive environmental chemical receptor, previously implicated in smoking-related cancers, in IFN signaling in human lung adenocarcinoma (LUAD) cells. Deletion of the aryl hydrocarbon receptor (AhR) from A549 LUAD cells significantly decreased baseline JAK2, STAT1, STAT3, IRF1 (a JAK/STAT target), PD-L1, PD-L2, and IDO1 expression. IFNγ and IFNα increased expression of JAK/STAT and immune checkpoint genes and proteins, but these increases were significantly diminished or absent in AhR-knockout cells. The AhR similarly controls IFN-induced, JAK/STAT-driven increases in multiple MHC class I- and class II-related genes. AhR control of type I and type II interferon signaling is mediated through up-regulation of a lncRNA, the IFN-stimulated non-coding RNA 1 (INCR1), and through repression of an RNA-binding protein, heterogeneous nuclear ribonucleoprotein H1 (HNRNPH1), which sequesters JAK/STAT-related and immune checkpoint gene transcripts. The data suggest that the AhR is a key mediator of tumor immunosuppression through regulation of IFN-induced INCR1 and JAK/STAT signaling and, thereby, expression of immune checkpoints. However, that immunosuppression may be tempered by AhR control of MHC expression. Given the multiple roles of JAK/STAT signaling in the immune system, the results also suggest multiple levels on which the AhR may affect tumor immunity.

Epstein-Barr virus (EBV)-associated gastric cancers (EBVaGCs) account for about 10% of gastric cancers globally, with higher prevalence in East Asia and Latin America. These cancers develop through a "gastritis-infection-cancer sequence" and are characterized by unique molecular signatures, including CpG island methylator phenotype and mutations in ARID1A and PIK3CA genes. EBVaGCs typically present in the proximal stomach with diffuse-type histology and dense lymphocytic infiltration. Key viral proteins EBNA1 and LMP2A drive oncogenesis by altering cellular processes and immune responses. The IFN-γ signature and extensive epigenetic modifications contribute to their distinct profile. Despite often presenting at advanced stages, EBVaGCs generally have a more favorable prognosis. EBV employs sophisticated strategies to evade immune detection, utilizing latent proteins and noncoding RNAs. Paradoxically, despite an immune-hot environment, EBVaGCs demonstrate effective immune evasion, partly due to the expression of immune checkpoint molecules like PD-L1 and LAG3. Treatment approaches vary based on disease stage, from endoscopic resection for early-stage cancers to systemic therapies for advanced cases. Immunotherapy, particularly PD-1/PD-L1 inhibitors, shows promising results. Emerging research suggests combining these with LAG3 inhibitors may enhance efficacy. Ongoing research and advanced genomic techniques continue to reveal new insights, paving the way for personalized therapies and novel diagnostic approaches.

Colon adenocarcinoma (COAD) is the most common subtype of colorectal cancer, originating from glandular cells in the colon. Despite diagnostic and therapeutic advances, its prognosis remains poor. Copper, an essential micronutrient, is involved in tumorigenesis and other biological processes. In this study, we identified copper metabolism-related genes (CMRG) associated with COAD prognosis from TCGA and GEO databases and constructed a CMRG-based risk model. We assessed its clinical relevance through analyses of immune infiltration, immunotherapy response, and drug sensitivity. Single-cell sequencing revealed the spatial and cellular distribution of CMRG in COAD tissues, providing insight into their roles in the tumour microenvironment. COX19 was selected for further validation, and in vitro experiments (western blot, PCR, siRNA, colony formation, and Transwell assays) confirmed its role in promoting COAD cell invasion and proliferation. These findings highlight the involvement of copper metabolism in COAD progression and suggest potential targets for therapy.

Immunotherapy emerges as a promising approach, marked by recent substantial progress in elucidating how the host immune response impacts tumor development and its sensitivity to various treatments. Immune checkpoint inhibitors have revolutionized cancer therapy by unleashing the power of the immune system to recognize and eradicate tumor cells. Among these, inhibitors targeting the programmed cell death protein 1 (PD-1) and its ligand (PD-L1) have garnered significant attention due to their remarkable clinical efficacy across various malignancies. This review delves into the mechanisms of action, clinical applications, and emerging therapeutic strategies surrounding PD-1/PD-L1 blockade. We explore the intricate interactions between PD-1/PD-L1 and other immune checkpoints, shedding light on combinatorial approaches to enhance treatment outcomes and overcome resistance mechanisms. Furthermore, we discuss the expanding landscape of immune checkpoint inhibitors beyond PD-1/PD-L1, including novel targets such as CTLA-4, LAG-3, TIM-3, and TIGIT. Through a comprehensive analysis of preclinical and clinical studies, we highlight the promise and challenges of immune checkpoint blockade in cancer immunotherapy, paving the way for future advancements in the field.

Senescent and cancer cells share common inflammatory characteristics, including factors of the senescence-associated secretory phenotype (SASP) and the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway. Inflammation in the tumor microenvironment not only provides an opportunity for immune cells to attack cancer cells, but also promotes cancer invasion and metastasis. Immune checkpoint molecule PD-L1 is transcriptionally induced by inflammation, and the immunological state of PD-L1-positive tumors influences the efficacy of Immune checkpoint inhibitors (ICIs). ICIs are effective against the PD-L1-positive "hot" tumors; however, the non-immunoactive "cold" tumors that express PD-L1 rarely respond to ICIs, suggesting that converting PD-L1-positive "cold" tumors into "hot" tumors would improve the efficacy of ICIs. To eliminate cancer via the innate immune system, a therapeutic strategy for manipulating inflammatory responses must be established. To date, the molecular mechanisms of inflammation-induced tumorigenesis are not yet fully understood. However, it is becoming clear that the regulatory mechanisms of inflammation in cancer via the cGAS-STING pathway play an important role in both cancer and sensescent cells. In this review, we focus on inflammation and immune escape triggered by DNA damage in cancer and senescent cells.

Suppression of tumor-reactive CD8+ T cells is common within the tumor microenvironment. However, little is known about how tumors systemically affect the overall CD8+ T cell compartment. Here we demonstrate that peripheral blood CD8+ T cells from patients with lung cancer showed altered compositions particularly within CD45RA-CCR7- effector memory subpopulation. Specifically, patients with lung cancer exhibited increased frequency of more differentiated effector memory cells, which are less susceptible to T cell-receptor-induced proliferation. Further analysis using single-cell RNA sequencing revealed that these alterations were correlated with reduced quiescence and increased spontaneous activation at a systemic level, indicative of homeostatic dysregulation of the entire CD8+ T cell population. This phenomenon was found to be correlated with a poor clinical response to immune checkpoint inhibitor therapy across four independent cohorts, consisting of a total of 224 patients with lung cancer. These findings suggest that lung cancers continue to counteract potentially tumor-reactive CD8+ T cells by inducing homeostatic dysregulation of the entire CD8+ T cell compartment systematically.

A striking characteristic of liver cancer is its extensive heterogeneity, particularly with regard to its varied response to immunotherapy. In this study, we employed multimodal sequencing approaches to explore the various aspects of neoadjuvant nivolumab treatment in liver cancer patients. We used spatially-resolved transcriptomics, single- and bulk-cell transcriptomics, and TCR clonotype analyses to examine the spatiotemporal dynamics of the effects of nivolumab. We observed a significantly higher clonal expansion of T cells in the tumors of patients who responded to the treatment, while lipid accumulation was detected in those of non-responders, likely due to inherent differences in lipid metabolic processes. Furthermore, we found a preferential enrichment of T cells, which was associated with a better drug response. Our results also indicate a functional antagonism between tumor-associated macrophages (TAMs) and CD8 cells and their spatial separation. Notably, we identified a UBASH3B/NR1I2/CEACAM1/HAVCR2 signaling axis, highlighting the intense communication among TAMs, tumor cells, and T-cells that leads to pro-tumorigenic outcomes resulting in poorer nivolumab response. In summary, using integrative multimodal sequencing investigations, combined with the multi-faceted exploration of pre- and post-treatment samples of neoadjuvant nivolumab-treated HCC patients, we identified useful mechanistic determinants of therapeutic response. We also reconstructed the spatiotemporal model that recapitulates the physiological restoration of T cell cytotoxicity by anti-PD1 blockade. Our findings could provide important biomarkers and explain the mechanistic basis differentiating the responders and non-responders.

IFNγ plays both positive and negative roles in the regulation of innate and adaptive immune responses against tumors and virally infected tissues by upregulating CXCL10 and PD-L1 expression.

To identify novel pathways and drugs that regulate the IFNγ-dependent PD-L1, we expressed GFP under the control of mouse PD-L1 promoter in mouse cancer cells that up regulate PD-L1 and CXCL10 in response to IFNγ stimulation. Using these cells, we screened an FDA approved library of 1496 small molecules known for their ability to inhibit IFNγ-dependent increase in PD-L1.

We identified 46 drugs that up regulated and 4 that down regulated IFNγ-dependent PD-L1 expression. We discovered that in addition to the known JAK inhibitors Ruxolitinib and Baricitinib, Dinaciclib, a CDK1/2/5/9 inhibitor, and Ganetespib, a Hsp90 inhibitor, significantly inhibit both PD-L1 and CXCL10 expression in the model cells. Furthermore, both drugs suppressed IFNγ-dependent CXCL10 and PD-L1 expression in-vitro in primary human lung cells and human cancer cells. These drugs also significantly inhibited delayed-type hypersensitivity (DTH) in-vivo in an inflammation mouse model.

Our novel screening platform can therefore be used in the future to identify novel immunomodulators and pathways in cancer and inflammation, expanding therapeutic horizons.

Gastric cancer (GC) is linked to high morbidity and mortality rates. Approximately two-thirds of GC patients are diagnosed at an advanced or metastatic stage. Conventional treatments for GC, including surgery, radiotherapy, and chemotherapy, offer limited prognostic improvement. Recently, immunotherapy has gained attention for its promising therapeutic effects in various tumors. Immunotherapy functions by activating and regulating the patient's immune cells to target and eliminate tumor cells, thereby reducing the tumor burden in the body. Among immunotherapies, immune checkpoint inhibitors (ICIs) are the most advanced. ICIs disrupt the inhibitory protein-small molecule (PD-L1, CTLA4, VISTA, TIM-3 and LAG3) interactions produced by immune cells, reactivating these cells to recognize and attack tumor cells. However, adverse reactions and resistance to ICIs hinder their further clinical and experimental development. Therefore, a comprehensive understanding of the advancements in ICIs for GC is crucial. This article discusses the latest developments in clinical trials of ICIs for GC and examines combination therapies involving ICIs (targeted therapy, chemotherapy, radiotherapy), alongside ongoing clinical trials. Additionally, the review investigates the tumor immune microenvironment and its role in non-responsiveness to ICIs, highlighting the function of tumor immune cells in ICI efficacy. Finally, the article explores the prospects and limitations of new immunotherapy-related technologies, such as tumor vaccines, nanotechnologies, and emerging therapeutic strategies, aiming to advance research into personalized and optimized immunotherapy for patients with locally advanced gastric cancer.

SARS-CoV-2 and other viruses rely on the protease function of the TMPRSS2 protein to invade host cells. Despite cancer patients often experience poorer outcomes following SARS-CoV-2 infection, the role of TMPRSS2 in different cancer types has not yet been analyzed in detail. Therefore, the aim of the study was to determine the expression, function and clinical relevance of TMPRSS2 in tumors.

Publicly accessible RNA sequencing data from tumors, adjacent tissues and whole blood samples of COVID-19 patients as well as data from human tumor epithelial and endothelial cells infected with SARS-CoV-2 were analyzed for TMPRSS2 expression and correlated to the expression of immune-relevant genes and clinical parameters. In vitro models of cells transfected with TMPRSS2 (TMPRSS2high), siTMPRSS2 or mock controls (TMPRSS2low cells) were analyzed by qPCR, flow cytometry, ELISA and Western blot for the expression of immune response-relevant molecules. Co-cultures of TMPRSS2 model systems with blood peripheral mononuclear cells were employed to evaluate immune cell migration, cytotoxicity and cytokine release.

Higher expression levels of TMPRSS2 were found in blood from patients infected with SARS-CoV-2, while TMPRSS2 expression levels significantly varied between the tumor types analyzed. TMPRSS2high tumor cells exhibit increased activity of the interferon (IFN) signal pathway accompanied by an increased expression of class I human leukocyte antigens (HLA-I) and programmed cell death ligand 1 (PD-L1) elevated interleukin 6 (IL-6) secretion and reduced NK cell-mediated cytotoxicity compared to TMPRSS2low mock controls. Treatment with a Janus kinase (JAK) 2 inhibitor or TMPRSS2-specific siRNA decreased TMPRSS2 expression. Co-cultures of the in vitro TMPRSS2 models with peripheral blood mononuclear cells in the presence of the immune checkpoint inhibitor nivolumab resulted in a significantly increased migration and infiltration of immune cells towards TMPRSS2high cells and a reduced release of the innate immunity-related cytokines CCL2 and CCL3.

This study provides novel insights into the role of TMPRSS2 in various tumor systems and the impact of SARS-CoV-2 infection on the host immunogenicity via the activation of immune-relevant pathways. These findings were linked to the efficacy of immune checkpoint inhibitor therapy, offering a potential alternative strategy to mitigate the severity of COVID-19.

Despite advances in cancer immunotherapy, such as targeting the PD-1/PD-L1 axis, a substantial number of patients harbor tumors that are resistant or relapse. Selective engagement of T-cell co-stimulatory molecules with bispecific antibodies may offer novel therapeutic options by enhancing signal 1-driven activation occurring via T-cell receptor engagement. In this study, we report the development and preclinical characterization of NI-3201, a PD-L1×CD28 bispecific antibody generated on the κλ-body platform that was designed to promote T-cell activity and antitumor function through a dual mechanism of action. We confirmed that NI-3201 blocks the PD-L1/PD-1 immune checkpoint pathway and conditionally provides T-cell co-stimulation via CD28 (signal 2) when engaging PD-L1+ tumors or immune cells. In systems with signal 1-primed T cells, NI-3201 enhanced potent effector functionality: in vitro through antigen-specific recall assays with cytomegalovirus-specific T cells and in vivo by inducing tumor regression and immunologic memory in tumor-associated antigen-expressing MC38 syngeneic mouse models. When T-cell engagers were used to provide synthetic signal 1, the combination with NI-3201 resulted in synergistic T cell-dependent cytotoxicity and potent antitumor activity in two humanized mouse tumor models. Nonhuman primate safety assessments showed favorable tolerability and pharmacokinetics at pharmacologically active doses. Quantitative systems pharmacology modeling predicted that NI-3201 exposure results in antitumor activity in patients, but this remains to be investigated. Overall, this study suggests that by combining PD-L1 blockade with safe and effective CD28 co-stimulation, NI-3201 has the potential to improve cancer immunotherapy outcomes, and the clinical development of NI-3201 for PD-L1+ solid tumors is planned.

While immunotherapy has shown some efficacy in lung adenocarcinoma (LUAD) patients, many respond only partially or not at all. One limitation in improving outcomes is the lack of a complete understanding of immune checkpoint regulation. Here, we investigated a possible link between an environmental chemical receptor implicated in lung cancer and immune regulation, the AhR, a known but counterintuitive mediator of immunosuppression (interferon (IFN)-γ), and regulation of two immune checkpoints (PD-L1 and IDO). AhR gene-edited LUAD cell lines, a syngeneic LUAD mouse model, bulk and scRNA sequencing of LUADs and tumor-infiltrating T cells were used to map out a signaling pathway leading from IFN-γ through the AhR to JAK/STAT, PD-L1, IDO, and tumor-mediated immunosuppression. The data demonstrate that: (1) IFN-γ activation of the JAK/STAT pathway leading to PD-L1 and IDO1 up-regulation is mediated by the AhR in murine and human LUAD cells, (2) AhR-driven IDO1 induction results in the production of Kynurenine (Kyn), an AhR ligand, which likely mediates an AhR→IDO1→Kyn→AhR amplification loop, (3) transplantation of AhR-knockout LUAD cells results in long-term tumor immunity in most recipients. (4) The 23% of AhR-knockout tumors that do grow do so at a much slower pace than controls and exhibit higher densities of CD8+ T cells expressing markers of immunocompetence, increased activity, and increased cell-cell communication. The data definitively link the AhR to IFN-γ-induced JAK/STAT pathway and immune checkpoint-mediated immunosuppression and support the targeting of the AhR in the context of LUAD.

We evaluated whether indoleamine 2,3-dioxygenase (IDO1) inhibitor (IDOi) BMS986205 + PD-1 inhibitor nivolumab enhanced T-cell activity and augmented immune-mediated antitumor responses in untreated, resectable head and neck squamous cell carcinoma (HNSCC). We employed response-adaptive surgical timing to identify responders to immunotherapy and enhance their response.

Patients with HNSCC were 3:1 randomized to receive nivolumab with or without BMS986205 orally daily (NCT03854032). In the combination arm, BMS986205 was initiated 7 days prior to nivolumab. Patients were stratified by human papillomavirus (HPV) status. Response-adaptive surgical timing involved response assessment by radiographic criteria 4 weeks after treatment with nivolumab in both arms. Nonresponders underwent surgical resection, whereas responders received 4 more weeks of randomized therapy before surgery. Biomarker analysis utilized pathologic treatment response (pTR) and RNA sequencing.

Forty-two patients were enrolled, and the addition of IDOi to nivolumab did not result in greater rate of radiographic response (P = 0.909). Treatment was well tolerated, with only 2 (5%) patients experiencing grade 3 immune-related adverse events. The addition of IDOi augmented rates of pTR in patients with high baseline IDO1 RNA expression (P < 0.05). Response-adaptive surgical timing demonstrated reliability in differentiating pathologic responders versus nonresponders (P = 0.009). A pretreatment NK cell signature, PD-L1 status, and IFN-γ expression in the HPV- cohort correlated with response. The HPV+ cohort found B-cell and cancer-associated fibroblast signatures predictive of response/nonresponse.

Response-adaptive surgical timing enhanced treatment response. IDOi BMS986205 augmented pTR in patients with high IDO1 expression in baseline samples, indicating a need for identifying and targeting resistant nodes to immunotherapy. HPV status-dependent signatures predicting response to immunotherapy in HNSCC warrant further study.

Signal regulatory protein alpha (SIRPα) inhibits phagocytosis by macrophages by interacting with CD47. Despite its known role in various cancers, the clinical significance of SIRPα in gastric cancer (GC) remains unclear. This study aimed to elucidate the clinical implications of SIRPα in GC, exploring its relevance to immunotherapy efficacy and the tumor microenvironment.

Two cohorts were studied: a gastrectomy cohort (137 patients) and an immune checkpoint inhibitor (ICI)-treated cohort (19 patients with unresectable advanced GC who received nivolumab). Immunohistochemistry was used to assess SIRPα, CD80, CD163, CD8, and PD-L1 expressions. Kaplan-Meier curves and Cox models were used to analyze the clinical outcomes. In vitro experiments used peripheral blood mononuclear cells and THP-1 macrophage cell lines to examine SIRPα responses to interferon-γ (IFN-γ).

In the gastrectomy cohort, high SIRPα expression correlated with advanced tumor invasion, distant metastasis, and poor recurrence-free and overall survival. SIRPα expression was also significantly associated with macrophage and CD8 + T cells infiltration and PD-L1 expression. In the ICI-treated cohort, high SIRPα expression was associated with better overall survival after nivolumab induced. Moreover, in vitro IFN-γ stimulation upregulated SIRPα expression on monocytes in peripheral blood mononuclear cells and THP-1 cells, suggesting high SIRPα expression may reflect an active immune microenvironment.

SIRPα expression is not only a poor prognostic factor for GC, possibly through inhibition of the CD47-SIRP⍺ pathway, but may also be involved in the efficacy of ICI therapy in GC.

Endocervical adenocarcinoma (ECA) comprises a heterogeneous group of diseases whose incidence has increased significantly in recent decades. ECA can be histologically classified into human papillomavirus-associated (HPVA) and non-HPVA (NHPVA) types. Given the variability in pathological features and clinical behavior between the subtypes, evaluating their respective immune microenvironments is essential. They can be categorized into distinct tumor microenvironment immune types (TMIT).

A total of 540 surgically resected ECA samples were classified into HPVA and NHPVA subgroups. Tumor-infiltrating immune markers were assessed using immunohistochemistry. We categorized ECA into four TMIT based on PD-L1 and CD8+ tumor-infiltrating lymphocytes (TILs) expression, and analyzed their prognostic significance.

PD-L1 positivity was observed in 319 out of 464 (68.8%) HPVA and 55 out of 76 (72.4%) NHPVA. Across the entire cohort, high CD8+ TILs expression was significantly associated with improved disease-free survival (DFS, p=0.018) and overall survival (OS, p=0.031). A total of 177 samples (32.8%) were classified as TMIT I (high PD-L1 and high CD8+ TILs), exhibiting markedly denser immune cell infiltration compared to the other TMIT groups. In NHPVA subgroup, TMIT was significantly associated with both DFS (p=0.005) and OS (p=0.003). Multivariate analysis identified TMIT as an independent prognostic factor for DFS in the NHPVA group, with TMIT I indicating a more favorable prognosis (p=0.042).

TMIT I group within the NHPVA population is most likely to benefit from PD-L1/PD-1 blockade immunotherapies. The immune classification of ECA demonstrates significant prognostic value, suggesting its potential utility in guiding clinical stratification and therapeutic decision-making.

Gastric cancer (GC) ranks as the fifth most prevalent malignant neoplasm globally, with an increased death rate despite recent advancements in research and therapeutic options. Different molecular subtypes of GC have distinct interactions with the immune system, impacting the tumor microenvironment (TME), prognosis, and reaction to immunotherapy. Tumor-infiltrating lymphocytes (TILs) in the TME are crucial for preventing tumor growth and metastasis, as evidenced by research showing that patients with GC who have a significant density of TILs have better survival rates. But cancer cells have evolved a variety of mechanisms to evade immune surveillance, both sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) and Programmed Death-Ligand 1 (PD-L1) playing a pivotal role in the development of an immunosuppressive TME. They prevent T cell activation and proliferation resulting in a decrease in the immune system's capacity to recognize and eliminate malignant cells. These immune checkpoint molecules function via different but complementary mechanisms, the expression of Siglec-15 being mutually exclusive with PD-L1 and, therefore, providing a different therapeutic approach. The review explores how TILs affect tumor growth and patient outcomes in GC, with particular emphasis on their interactions within the TME and potential targeting of the PD-L1 and Siglec-15 pathways for immunotherapy.

The hepatocyte growth factor (HGF) along with its receptor (c-MET) are crucial in preserving standard cellular physiological activities, and imbalances in the c-MET signaling pathway can lead to the development and advancement of tumors. It has been extensively demonstrated that immune checkpoint inhibitors (ICIs) can result in prolonged remission in certain patients. Nevertheless, numerous preclinical studies have shown that MET imbalance hinders the effectiveness of anti-PD-1/PD-L1 treatments through various mechanisms. Consequently, clarifying the link between the c-MET signaling pathway and the tumor microenvironment (TME), as well as uncovering the effects of anti-MET treatment on ICI therapy, is crucial for enhancing the outlook for tumor patients. In this review, we examine the impact of abnormal activation of the HGF/c-MET signaling pathway on the control of the TME and the processes governing PD-L1 expression in cancer cells. The review thoroughly examines both clinical and practical evidence regarding the use of c-MET inhibitors alongside PD-1/PD-L1 inhibitors, emphasizing that focusing on c-MET with immunotherapy enhances the effectiveness of treating MET tumors exhibiting elevated PD-L1 expression.

The T-cell antigen coupler (TAC) is a chimeric receptor that facilitates tumor antigen-specific activation of T cells by co-opting the endogenous T-cell receptor complex in the absence of tonic signaling. Previous data demonstrate that the TAC affords T cells with the ability to induce durable and safe antitumor responses in preclinical models of hematologic and solid tumors. In this study, we describe the preclinical pharmacology and safety of an autologous Claudin 18.2 (CLDN18.2)-directed TAC T-cell therapy, TAC01-CLDN18.2, in preparation for a phase I/II clinical study in subjects with CLDN18.2-positive solid tumors. Following a screen of putative TAC constructs, the specificity, activity, and cytotoxicity of TAC T cells expressing the final CLDN18.2-TAC receptor were evaluated in vitro and in vivo using gastric, gastroesophageal, and pancreatic tumor models as well as human cells derived from normal tissues. CLDN18.2-specific activity and cytotoxicity of CLDN18.2-TAC T cells were observed in coculture with various 2D tumor cultures naturally expressing CLDN18.2 as well as tumor spheroids. These effects occurred in models with low antigen levels and were positively associated with increasing CLDN18.2 expression. CLDN18.2-TAC T cells effectively eradicated established tumor xenografts in mice in the absence of observed off-target or on-target/off-tumor effects, elicited durable efficacy in recursive killing and tumor rechallenge experiments, and remained unreactive in coculture with human cells representing vital organs. Thus, the data demonstrate that CLDN18.2-TAC T cells can induce a specific and long-lasting antitumor response in various CLDN18.2-positive solid tumor models without notable TAC-dependent toxicities, supporting the clinical development of TAC01-CLDN18.2.

Non-Small Cell Lung Cancer (NSCLC) is the leading cause of cancer death worldwide. Although immune checkpoint inhibitors (ICIs) have shown remarkable clinical efficacy, they can also induce a paradoxical cancer acceleration, known as hyperprogressive disease (HPD), whose causative mechanisms are still unclear.

This study investigated the mechanisms of ICI resistance in an HPD-NSCLC model. Two primary cell cultures were established from samples of a NSCLC patient, before ICI initiation ("baseline", NSCLC-B) and during HPD ("hyperprogression", NSCLC-H). The cell lines were phenotypically and molecularly characterized through immunofluorescence, Western Blotting and RNA-Seq analysis. To assess cell plasticity and aggressiveness, cellular growth patterns were evaluated both in vitro and in vivo through 2D and 3D cell growth assays and patient-derived xenografts establishment. In vitro investigations, including the evaluation of cell sensitivity to interferon-gamma (IFN-γ) and cell response to PD-L1 modulation, were conducted to explore the influence of these factors on cell plasticity regulation.

NSCLC-H exhibited increased expression of specific CD44 isoforms and a more aggressive phenotype, including organoid formation ability, compared to NSCLC-B. Plastic changes in NSCLC-H were well described by a deep transcriptome shift, that also affected IFN-γ-related genes, including PD-L1. IFN-γ-mediated cell growth inhibition was compromised in both 2D-cultured NSCLC-B and NSCLC-H cells. Further, the cytokine induced a partial activation of both type I and type II IFN-pathway mediators, together with a striking increase in NSCLC-B growth in 3D cell culture systems. Finally, low IFN-γ doses and PD-L1 modulation both promoted plastic changes in NSCLC-B, increasing CD44 expression and its ability to produce spheres.

Our findings identified plasticity as a relevant hallmark of ICI-mediated HPD by demonstrating that ICIs can modulate the IFN-γ and PD-L1 pathways, driving tumor cell plasticity and fueling HPD development.

Cutaneous squamous cell carcinoma (cSCC) is an increasingly common malignancy of the skin and the leading cause of death from skin cancer in adults over the age of 85. Fibroblast growth factor receptor 2 (FGFR2) has been identified as an important effector of signaling pathways that lead to the growth and development of cSCC. In recent years, there have been numerous studies evaluating the role FGFR2 plays in multiple cancers, its contribution to resistance to anticancer therapy, and new drugs that may be used to inhibit FGFR2. This review will provide an overview of our current understanding of FGFR2 and potential mechanisms in which we can target FGFR2 in cSCC. The goals of this review are the following: (1) to highlight our current knowledge of the role of FGFR2 in healthy skin and contrast this with its role in the development of cancer; (2) to further explain the specific molecular mechanisms that FGFR2 uses to promote tumorigenesis; (3) to describe how FGFR2 contributes to more invasive disease; (4) to describe its immunosuppressive effects in skin; and (5) to evaluate its effect on current anticancer therapy and discuss therapies on the horizon to target FGFR2 related malignancy.

Immune checkpoints are essential for regulating excessive autoimmune responses and maintaining immune homeostasis. However, in the tumor microenvironment, these checkpoints can lead to cytotoxic T cell exhaustion, allowing cancer cells to evade immune surveillance and promote tumor progression. The expression of programmed death-ligand 1 (PD-L1) in cancer cells is associated with poor prognoses, reduced survival rates, and lower responses to therapies. Consequently, downregulating PD-L1 expression has become a key strategy in developing immune checkpoint inhibitors (ICIs). Caryophylli cortex (CC), derived from the bark of the clove tree Syzygium aromaticum, possesses antioxidant and cytotoxic properties against cancer cells, yet its potential as an ICI remains unclear.

In this study, we aimed to investigate whether CC extract modulates PD-L1 expression in cancer cells and activates T cell immunity through a co-culture system of cancer cells and T cells, as well as in hPD-L1/MC-38 tumor-bearing animal models.

Our findings indicate that CC extract significantly downregulated both constitutive and inducible PD-L1 expression at non-toxic concentrations for cancer cells while simultaneously enhancing cancer cell mortality and T cell activity in the co-culture system. Furthermore, the administration of CC extract to hPD-L1/MC-38 tumor-bearing mice resulted in a greater than 70% reduction in tumor growth and increased infiltration of CD8+ T cells within the tumor microenvironment. Principal component analysis identified bergenin, chlorogenic acid, and ellagic acid as active ICIs.

These findings suggest that CC extract exerts a potent antitumor effect as an immune checkpoint blocker by inhibiting PD-L1 expression in cancer cells and disrupting the PD-1/PD-L1 interaction.

Cancer is a global health problem and one of the leading causes of mortality. Immune checkpoint inhibitors have revolutionized the field of oncology, emerging as a powerful treatment strategy. A key pathway that has garnered considerable attention is programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1). The interaction between PD-L1 expressed on tumor cells and PD-1 reduces the innate immune response and thus compromises the capability of the body's immune system. Furthermore, it controls the phenotype and functionality of innate and adaptive immune components. A range of monoclonal antibodies, including avelumab, atezolizumab, camrelizumab, dostarlimab, durvalumab, sinitilimab, toripalimab, and zimberelimab, have been developed for targeting the interaction between PD-1 and PD-L1. These agents can induce a broad spectrum of autoimmune-like complications that may affect any organ system. Recent studies have focused on the effect of various natural compounds that inhibit immune checkpoints. This could contribute to the existing arsenal of anticancer drugs. Several bioactive natural agents have been shown to affect the PD-1/PD-L1 signaling axis, promoting tumor cell apoptosis, influencing cell proliferation, and eventually leading to tumor cell death and inhibiting cancer progression. However, there is a substantial knowledge gap regarding the role of different natural compounds targeting PD-1 in the context of cancer. Hence, this review aims to provide a common connection between PD-1/PD-L1 blockade and the anticancer effects of distinct natural molecules. Moreover, the primary focus will be on the underlying mechanism of action as well as the clinical efficacy of bioactive molecules. Current challenges along with the scope of future research directions targeting PD-1/PD-L1 interactions through natural substances are also discussed.

The tumor immune microenvironment (TIME) plays a critical role in cancer development and response to immunotherapy. Immune checkpoint inhibitors aim to reverse the immunosuppressive effects of the TIME, but their success has been limited. Immunotherapy directed at PD-1/PD-L1 has been widely employed, yielding positive results. Unfortunately, the gradual emergence of resistance to PD-1/PD-L1 inhibition has diminished the effectiveness of this immunotherapy in cancer patients, emphasizing the need for new compounds that will be more effective in managing immunotherapy. This study investigated the effect of the natural compound cardamonin on PD-L1 expression and its ability to modulate the TIME, which could overcome immunotherapy resistance in triple-negative breast cancer (TNBC). This investigation used two genetically distinct triple-negative breast cancer cell lines, MDA-MB-231 (MDA-231) and MDA-MB-468 (MDA-468). The results show that TNBC cell treatment with cardamonin inhibited PD-L1 expression and reduced JAK1 and STAT3 levels in MDA-231 cells, while it increased JAK1 expression in MDA-468 cells. Also, cardamonin increased the expression of Nrf2 in both cell lines. In addition, cardamonin decreased MUC1, NF-κB1, and NF-κB2 expression in MDA-MB-231 cells and selectively reduced NF-κB1 expression in MDA-468 cells. Furthermore, cardamonin very potently reduced the inflammatory cytokine CCL2 levels. The decrease in CCL2 release reduces the chemoattraction of macrophages in the tumor microenvironment, which may increase the effectiveness of PD-1/PD-L1 inhibition and allow T-cell infiltration. These findings suggest that the cardamonin modulation of TIME holds promise in reversing resistance of PD-1/PD-L1 inhibition when it is used along with immunotherapy in TNBC treatment.

Dental pulp stem cells (DPSCs) have acquired noteworthy attention for their application in treating ischemic diseases and facilitating tissue regeneration. However, the host's immune response following allogenic DPSC transplantation often handicaps the long-term survival of transplanted cells, thereby limiting the application of DPSCs in cell therapy. This study aims to investigate whether genetic modification can alleviate the immunogenicity of DPSCs.

Beta 2-microglobulin (B2M) and the class II histocompatibility complex transactivator (CIITA) were individually knocked down in DPSCs by lentiviral particles encoding short hairpin (sh) RNAs. The self-renewal capacity and pluripotency of DPSCs-shB2M (B2M silenced DPSCs) and DPSCs-shCIITA (CIITA silenced DPSCs) were evaluated by CCK8 and differentiation assays including osteogenesis, adipogenesis, and neurogenesis. The expression of HLA-I and HLA-II in DPSCs-shB2M and DPSCs-shCIITA after IFN-γ treatment were analyzed by western blotting, immunofluorescence, and flow cytometry. The function of genetically modified cells was assessed by leukocyte-mediated cytotoxicity and T-cell proliferation assays.

Western blotting, immunofluorescence, and flow cytometry revealed that DPSCs-shB2M and DPSCs-shCIITA exhibited impaired IFN-γ inducible HLA-I and HLA-II expression. There were no significant differences in the self-renewal capacity and pluripotency among DPSCs-shB2M, DPSCs-shCIITA, and control groups (p > 0.05). Lower leukocyte-mediated cytotoxicity and higher cell survival rates were found in DPSCs-shB2M and DPSCs-shCIITA groups compared to the control (p < 0.05). T cell proliferation was significantly inhibited in both DPSCs-shB2M and DPSCs-shCIITA groups (p < 0.05).

Genetic knockdown of B2M or CIITA in DPSCs substantially reduced their immunogenicity without compromising their stemness, thereby broadening the clinical application of DPSCs in cell therapy and tissue regeneration.

This investigation evaluated the mechanism of hsa_circ_0000423 in colorectal cancer (CRC).

The hsa_circ_0000423 gene was identified by bioinformatics analyses of GEO circRNA microarrays, and its expression in CRC was investigated. Based on this, in vitro experiments were conducted. Assays with dual luciferase reporter and RIP were conducted to detect interactions between hsa_circ_0000423, miR-369-3p and CCND1. Cell proliferation was measured by MTT and colony formation assay assays, apoptosis was detected by flow cytometry, migration and invasion were detected by Transwell, and expression of EMT-related proteins was detected by Western Blot. SW480 cells and T cells were co-cultured to assess immune escape.

hsa_circ_0000423 and CCND1 were elevated in CRC while miR-369-3p was downregulated Silencing hsa_circ_0000423 resulted in reduced CCND1 expression by upregulating miR-369-3p. Overexpressing CCND1 or down-regulating miR-369-3p both interrupted the anti-tumor role of silencing hsa_circ_0000423 on CRC cells.

Hsa_circ_0000423 promotes CCND1 expression through competitive binding of miR-369-3p and promotes CRC cell development and immune escape.

In our previous study, we have isolated cytochalasin H (CyH) from endophytic fungus derived from mangrove plant and found that CyH inhibited the proliferation of non-small cell lung cancer (NSCLC) cells. Recently, epidermal growth factor receptor (EGFR) activation and programmed cell death 1 ligand (PD-L1) expression have been demonstrated to mediate NSCLC resistance to gefitinib, first-generation EGFR tyrosine kinase inhibitor (EGFR-TKI). Here, we further investigated the effect of CyH on EGFR activation, PD-L1 expression, and gefitinib sensitivity in NSCLC cell lines, A549 (wild-type EGFR), HCC827 (EGFR mutation), and NCI-H1975 (dual EGFR mutations and acquired gefitinib resistance) and animal model. Our results showed that CyH significantly inhibited EGFR activation and PD-L1 expression in NSCLC cells. Additionally, CyH dramatically promoted the inhibitory effect of gefitinib on the proliferation of A549 and HCC827 cells, and enhanced the sensitivity to gefitinib in NCI-H1975 cells. Moreover, CyH increased the inhibitory effect of gefitinib on EGFR activation and PD-L1 expression in HCC827 and NCI-H1975 cells. Animal experiments further demonstrated that CyH significantly promoted the inhibitory effect of gefitinib on the growth of NSCLC and the expression of Ki-67, p-EGFR, and PD-L1 in NCI-H1975 NSCLC xenograft tumors of nude mice. Furthermore, CyH inhibited the activation of JAK3/STAT signaling pathway. Taken together, our findings suggest that CyH promotes the sensitivity to gefitinib in NSCLC cells through the inhibition of EGFR activation and PD-L1 expression.

Background: Immune checkpoint inhibitor (ICI) therapy is becoming the standard of care for the treatment of advanced non-small-cell lung cancer. However, T-cell activation by ICIs frequently induces a flare-up of preexisting autoimmune diseases such as rheumatoid arthritis (RA). Janus kinase (JAK) inhibitors are increasingly used in the treatment of RA, but they could interfere with the efficacy of ICIs by inhibiting interferon signaling. Case Report: Here, we describe a case in which upadacitinib, a JAK1-selective inhibitor, was used to manage a severe RA flare-up occurring during ICI therapy with pembrolizumab, an anti-programmed cell death protein-1 antibody. A 54-year-old man with RA was diagnosed with grade IV lung squamous cell carcinoma. The patient had maintained RA remission for 4 years at the time of lung cancer diagnosis. After seven cycles of pembrolizumab therapy, the size of the primary tumor was markedly reduced, but a severe RA flare-up and organizing pneumonia (OP)-like pulmonary lesions occurred. Considering the severity of the flare-up, pembrolizumab was discontinued. Upadacitinib induced swift recovery from the RA flare-up and OP. Eleven months after the last pembrolizumab use, almost all metastatic lesions in the body had disappeared. We did not observe recurrence of lung cancer for more than 1 year during upadacitinib therapy. Conclusions: Upadacitinib could be a safe and effective option to treat severe RA flare-ups occurring during anti-PD-1 ICI therapy.

Interferon-γ (IFN-γ) is a potent cytokine critical for response to immunotherapy, yet conventional methods to systemically deliver this cytokine have been hindered by severe dose-limiting toxicities. Here, we engineered a strain of probiotic bacteria that home to tumors and locally release IFN-γ. A single intratumoral injection of these IFN-γ-producing bacteria was sufficient to drive systemic tumor antigen-specific antitumor immunity, without observable toxicity. Although cancer cells use various resistance mechanisms to evade immune responses, bacteria-derived IFN-γ overcame primary resistance to programmed cell death 1 (PD-1) blockade via activation of cytotoxic Foxp3-CD4+ and CD8+ T cells. Moreover, by activating natural killer (NK) cells, bacteria-derived IFN-γ also overcame acquired resistance mechanisms to PD-1 blockade, specifically loss-of-function mutations in IFN-γ signaling and antigen presentation pathways. Collectively, these results demonstrate the promise of combining IFN-γ-producing bacteria with PD-1 blockade as a therapeutic strategy for overcoming immunotherapy-resistant, locally advanced, and metastatic disease.

Immune checkpoint inhibitors (ICIs) that against programmed cell death protein-1 (PD-1) and its ligand PD-L1 have been approved as a promising treatment of many human cancers. However, the responses to these ICIs were limited in patients with ovarian cancer. Studies have indicated that the response to PD-1/PD-L1 blockade might be correlated with the PD-L1 expression level in cancer cells. Nucleophosmin (NPM/B23) was found to be a potential target for immunotherapy. Whether NPM/B23 plays a role in cancer-associated immunity, such as PD-1/PD-L1 axis, and its underlying mechanisms remain largely unknown in ovarian cancer.

We applied ovarian cancer cell lines as research models. The effect of modulating PD-L1 by NPM/B23 was subsequently confirmed via Western blot, flow cytometry, qRT-PCR, luciferase reporter assays, and immunoprecipitation. Protein stability and ubiquitin assay assays were used to analyze the interplay between NPM/B23 and NF-ĸB/p65 in PD-L1 regulation. The MOSEC/Luc xenograft mouse model was used to validate the role of NPM/B23-PD-L1 through tumor growth in vivo.

Our results revealed that NPM/B23 negatively regulates PD-L1 expression via a protein complex with NF-κB/p65 and through an IFN-γ pathway. Moreover, NPM/B23 inhibitor/modulator sensitized ovarian cancer cells to the anti-PD-1 antibody by regulating PD-L1 expression in the immunocompetent mouse model. Compared to anti-PD-1 antibody alone, a combination of anti-PD-1 antibody and NPM/B23 inhibitor/modulator showed reduced tumorigenesis and increased CD8+ T-cell expansion, thus contributing to prolonged survival on MOSEC/Luc-bearing mouse model.

Targeting NPM/B23 is a novel and potential therapeutic approach to sensitize ovarian cancer cells to immunotherapy.

While immunotherapy has shown efficacy in lung adenocarcinoma (LUAD) patients, many respond only partially or not at all. One limitation in improving outcomes is the lack of a complete understanding of immune checkpoint regulation. Here, we investigated a possible link between an environmental chemical receptor implicated in lung cancer and immune regulation, (the aryl hydrocarbon receptor/AhR), a known but counterintuitive mediator of immunosuppression (IFNγ), and regulation of two immune checkpoints (PD-L1 and IDO). AhR gene-edited LUAD cell lines, a syngeneic LUAD mouse model, bulk- and scRNA sequencing of LUADs and tumor-infiltrating leukocytes were used to map out a signaling pathway leading from IFNγ through the AhR to JAK/STAT, PD-L1, IDO, and tumor-mediated immunosuppression. The data demonstrate that: 1) IFNγ activation of the JAK/STAT pathway leading to PD-L1 and IDO1 upregulation is mediated by the AhR in murine and human LUAD cells, 2) AhR-driven IDO1 induction results in the production of Kynurenine (Kyn), an AhR ligand, which likely mediates an AhR→IDO1→Kyn→AhR amplification loop, 3) transplantation of AhR-knockout LUAD cells results in long-term tumor immunity in most recipients. 4) The 23% of AhR-knockout tumors that do grow do so at a much slower pace than controls and exhibit higher densities of CD8+ T cells expressing markers of immunocompetence, increased activity, and increased cell-cell communication. The data definitively link the AhR to IFNγ-induced JAK/STAT pathway and immune checkpoint-mediated immunosuppression and support the targeting of the AhR in the context of LUAD.

Neoadjuvant chemotherapy (NACT) is a viable therapeutic option for women diagnosed locally advanced cervical cancer (LACC). However, the factors influencing pathological response are still controversial. We collected pair specimens of 185 LACC patients before and after receiving NACT and conducted histological evaluation. 8 fresh tissues pre-treatment were selected from the entire cohort to conducted immune gene expression profiling. A novel pathological grading system was established by comprehensively assessing the percentages of viable tumor, inflammatory stroma, fibrotic stroma, and necrosis in the tumor bed. Then, 185 patients were categorized into either the good pathological response (GPR) group or the poor pathological response (PPR) group post-NACT, with 134 patients (72.4%, 134/185) achieving GPR. Increasing tumor-infiltrating lymphocytes (TILs) and tumor-infiltrating lymphocytes volume (TILV) pre-treatment were correlated with GPR, with TILV emerging as an independent predictive factor for GPR. Additionally, CIBERSORT analysis revealed noteworthy differences in the expression of immune makers between cPR and non-cPR group. Furthermore, a significantly heightened density of CD8 + T cells and a reduced density of FOXP3 + T cells were observed in GPR than PPR. Importantly, patients exhibiting GPR or inflammatory type demonstrated improved overall survival and disease-free survival. Notably, stromal type was an independent prognostic factor in multivariate analysis. Our study indicates the elevated TILV in pre-treatment specimens may predict a favorable response to NACT, while identifying stromal type in post-treatment specimens as an independent prognostic factor. Moreover, we proposed this pathological grading system in NACT patients, which may offer a more comprehensive understanding of treatment response and prognosis.