PD-L1 methylation restricts PD-L1/PD-1 interactions to control cancer immune surveillance

Targeting PD-1 post-translational modifications for improving cancer immunotherapy

Programmed cell death protein 1 (PD-1) is a critical immune checkpoint receptor that suppresses immune responses largely through its interaction with PD-L1. Tumors exploit this mechanism to evade immune surveillance, positioning immune checkpoint inhibitors targeting the PD-1/PD-L1 axis as groundbreaking advancements in cancer therapy. However, the overall effectiveness of these therapies is often constrained by an incomplete understanding of the underlying mechanisms. Recent research has uncovered the pivotal role of various post-translational modifications (PTMs) of PD-1, including ubiquitination, UFMylation, phosphorylation, palmitoylation, and glycosylation, in regulating its protein stability, localization, and protein-protein interactions. As much, dysregulation of these PTMs can drive PD-1-mediated immune evasion and contribute to therapeutic resistance. Notably, targeting PD-1 PTMs with small-molecule inhibitors or monoclonal antibodies (MAbs) has shown potential to bolster anti-tumor immunity in both pre-clinical mouse models and clinical trials. This review highlights recent findings on PD-1's PTMs and explores emerging therapeutic strategies aimed at modulating these modifications. By integrating these mechanistic insights, the development of combination cancer immunotherapies can be further rationally advanced, offering new avenues for more effective and durable treatments.

Baicalein tethers CD274/PD-L1 for autophagic degradation to boost antitumor immunity

Immune checkpoint inhibitors, especially those targeting CD274/PD-L1yield powerful clinical therapeutic efficacy. Thoughmuch progress has been made in the development of antibody-basedCD274 drugs, chemical compounds applied for CD274degradation remain largely unavailable. Herein,baicalein, a monomer of traditional Chinese medicine, isscreened and validated to target CD274 and induces itsmacroautophagic/autophagic degradation. Moreover, we demonstrate thatCD274 directly interacts with MAP1LC3B (microtubule associatedprotein 1 light chain 3 beta). Intriguingly, baicalein potentiatesCD274-LC3 interaction to facilitate autophagic-lysosomal degradationof CD274. Importantly, targeted CD274. degradation via baicaleininhibits tumor development by boosting T-cell-mediated antitumorimmunity. Thus, we elucidate a critical role of autophagy-lysosomalpathway in mediating CD274 degradation, and conceptually demonstratethat the design of a molecular "glue" that tethers the CD274-LC3interaction is an appealing strategy to develop CD274 inhibitors incancer therapy.Abbreviations: ATTECs: autophagy-tethering compounds; AUTACs: AUtophagy-TArgeting Chimeras; AUTOTACs: AUTOphagy-TArgeting Chimeras; AMPK: adenosine 5'-monophosphate (AMP)-activated protein kinase; BiFC: bimolecular fluorescence complementation; BafA1: bafilomycin A1; CD274/PD-L1/B7-H1: CD274 molecule; CQ: chloroquine; CGAS: cyclic GMP-AMP synthase; DAPI: 4'6-diamino-2-phenylindole; FITC: fluorescein isothiocyanate isomer; GFP: green fluorescent protein; GZMB: granzyme B; IHC: immunohistochemistry; ICB: immune checkpoint blockade; KO: knockout; KD: equilibrium dissociation constant; LYTAC: LYsosome-TArgeting Chimera; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MST: microscale thermophoresis; NFAT: nuclear factor of activated T cells; NFKB/NF-kB: nuclear factor kappa B; NSCLC: non-small-cell lung cancer; PDCD1: programmed cell death 1; PROTACs: PROteolysis TArgeting Chimeras; PRF1: perforin 1; PE: phosphatidylethanolamine; PHA: phytohemagglutinin; PMA: phorbol 12-myristate 13-acetate; STAT: signal transducer and activator of transcription; SPR: surface plasmon resonance; TILs: tumor-infiltrating lymphocyte; TME: tumor microenvironment.

Lysine methyltransferase SETD7 in cancer: functions, molecular mechanisms and therapeutic implications

Since its discovery as a histone methyltransferase, SETD7 has been implicated in many signaling pathways and carcinogenesis. SETD7 catalyzes the methylation of histone H3 and non-histone proteins, regulating their translation, stability and activity. SETD7 is frequently abnormally expressed and has a significant influence on cell proliferation, invasion, autophagy and immune response. As cancer is a complex disease, an outstanding concept in cancer biology is the "hallmarks of cancer". In this review, we focus on the involvement of SETD7 in the hallmarks of cancer, describing its functions and underlying mechanisms in detail. Additionally, we discuss non-coding RNAs and chemical inhibitors targeting SETD7, highlighting the potential and importance of SETD7 in cancer therapy.

Alternative Splicing in Lung Adenocarcinoma: From Bench to Bedside

Lung adenocarcinoma (LUAD) is a highly heterogeneous tumor and the most prevalent pathological type of lung cancer. The alternative splicing (AS) of mRNA enables the generation of multiple protein products from a single gene. This is a tightly regulated process that significantly contributes to the proteome diversity in eukaryotes. Recent multi-omics studies have delineated the splicing profiles that underline LUAD tumorigenesis from initiation to metastasis. Such progress holds robust promise to facilitate the development of screening strategies and individualized therapies. Perturbed AS fosters the emergence of novel neoantigen resources and disturbances in the immune microenvironment, which allow new investigations into modulatory targets for LUAD immunotherapy. This review presents an update on the landscape of dysregulated splicing events in LUAD and the associated mechanisms and theranostic perspectives with unique insights into AS-based immunotherapy, such as Chimeric Antigen Receptor T cell therapy. These AS variants can be used in conjunction with current therapeutic modules in LUAD, allowing bench to bedside translation to combat this highly malignant cancer.

Design, Synthesis, Evaluation, and SAR of 5-Phenylisoindoline Derivatives, a Potent Class of Small-Molecule Inhibitors Targeting the Programmed Cell Death-1/Programmed Cell Death-Ligand 1 (PD-1/PD-L1) Interaction

A novel series of 5-phenylisoindoline derivatives were designed, synthesized, and evaluated for their activity to inhibit the interaction of PD-1/PD-L1 through the homogeneous time-resolved fluorescence assay. Meanwhile, structure-activity relationships were discussed according to both experiments and calculations. Several compounds exhibited potent activity with an IC50 value less than 10 nM, especially D6 (4.8 nM). D6 could promote IFN-γ secretion and reduce the proportion of PD-L1 late apoptosis at 100 nM in the coculture model of peripheral blood mononuclear cells and hPD-L1-FC. Beyond this, the in vitro model showed D6 could lead to the weakening of migration caused by the PD-1/PD-L1 axis. Furthermore, D6 also displayed dose-dependent and low-toxic efficacy in the MC38 mouse tumor model with the tumor growth inhibition of 52.8% (20 mg/kg, ip) and 64.4% (160 mg/kg, i.g.). Mechanistic investigations suggested that D6 could activate the immune microenvironment in the tumor. Thus, D6 is a promising small molecule lead for blocking PD-1/PD-L1.

NAD+ Metabolism Reprogramming Drives SIRT1-Dependent Deacetylation Inducing PD-L1 Nuclear Localization in Cervical Cancer

Cervical cancer (CC) is a major health threat to women, with immunotherapies targeting the programmed death receptor 1/programmed death ligand 1(PD-1/PD-L1) axis showing promise but encountering resistance in a significant patient population. This resistance has driven a critical quest to uncover the underlying mechanisms. This study uncovers a novel metabolic axis involving the nicotinamide adenine dinucleotide (NAD+) salvage pathway enzyme nicotinamide phosphoribosyltransferase (NAMPT) and the deacetylase Sirtuin 1 (SIRT1), which regulates PD-L1 expression and nuclear localization in CC. This axis may be a key factor contributing to the resistance observed in immunotherapy. This study reveals that PD-L1 overexpression in cancers is regulated by both transcriptional and post-transcriptional processes. Acetyl-proteomic analysis pinpoints SIRT1 as a central regulator in the deacetylation of histone H3 at lysines 27, which may influence PD-L1 subcellular distribution. This finding reveals the epigenetic control of immune checkpoint proteins by metabolic pathways, offering a new perspective on the regulation of PD-L1. The identification of the NAMPT/SIRT1 metabolic axis as a critical factor suggests that targeting this axis may enhance therapeutic responses.

Programmed Cell Death Ligand as a Biomarker for Response to Immunotherapy: Contribution of Mass Spectrometry-Based Analysis

Immune checkpoint inhibition is a major component in today's cancer immunotherapy. In recent years, the FDA has approved a number of immune checkpoint inhibitors (ICIs) for the treatment of melanoma, non-small-cell lung, breast and gastrointestinal cancers. These inhibitors, which target cytotoxic T-lymphocyte antigen-4, programmed cell death (PD-1), and programmed cell death ligand (PD-L1) checkpoints have assumed a leading role in immunotherapy. The same inhibitors exert significant antitumor effects by overcoming tumor cell immune evasion and reversing T-cell exhaustion. The initial impact of this therapy in cancer treatment was justly described as revolutionary, however, clinical as well as research data which followed demonstrated that these innovative drugs are costly, are associated with potentially severe adverse effects, and only benefit a small subset of patients. These limitations encouraged enhanced research and clinical efforts to identify predictive biomarkers to stratify patients who are most likely to benefit from this form of therapy. The discovery and characterization of this class of biomarkers is pivotal in guiding individualized treatment against various forms of cancer. Currently, there are three FDA-approved predictive biomarkers, however, none of which on its own can deliver a reliable and precise response to immune therapy. Present literature identifies the absence of precise predictive biomarkers and poor understanding of the mechanisms behind tumor resistance as the main obstacles facing ICIs immunotherapy. In the present text, we discuss the dual role of PD-L1 as a biomarker for response to immunotherapy and as an immune checkpoint. The contribution of mass spectrometry-based analysis, particularly the impact of protein post-translational modifications on the performance of this protein is underlined.

Palmitoylation of PD-L1 Regulates Its Membrane Orientation and Immune Evasion

Recently identified palmitoylation of PD-L1 is essential for immune regulation. To elucidate the underlying molecular mechanism, we performed giant plasma membrane vesicle (GPMV) experiments, μs-scale all-atom molecular dynamics (MD) simulations, fluorescence resonance energy transfer (FRET) experiments, and immune killing experiments. GPMV experiments indicated that PD-L1 palmitoylation enhanced its lipid raft affinity. MD simulations revealed dramatically different membrane orientation states of PD-L1 in liquid-ordered (Lo, lipid raft) compared to liquid-disordered (Ld, nonraft) membrane environments, which was validated by FRET experiments. The Ld region promoted the "lie-down" orientation of PD-L1, which could inhibit its association with the PD-1 protein on immune cells and thus promote the immune killing of cancer cells. This hypothesis was supported by immune killing experiments using γδT cells as effector cells and NCI-H1299 lung cancer cells as target cells. In short, our study demonstrates that the palmitoylation affects PD-L1's membrane localization and then membrane orientation, which thus regulates its binding with T cell PD-1 and the immune regulation. These observations may guide therapeutic strategies by explicating the regulation of immune checkpoint proteins by post-translational modifications and membrane environments.

Epigenetic modifications in early stage lung cancer: pathogenesis, biomarkers, and early diagnosis

The integration of liquid biopsy with epigenetic markers offers significant potential for early lung cancer detection and personalized treatment. Epigenetic alterations, including DNA methylation, histone modifications, and noncoding RNA changes, often precede genetic mutations and are critical in cancer progression. In this study, we explore how liquid biopsy, combined with epigenetic markers, can provide early detection of lung cancer, potentially predicting onset up to 4 years before clinical diagnosis. We discuss the challenges of targeting epigenetic regulators, which could disrupt cellular balance if overexploited, and the need for maintaining key gene expressions in therapeutic applications. This review highlights the promise and challenges of using liquid biopsy and epigenetic markers for early-stage lung cancer diagnosis, with a focus on optimizing treatment strategies for personalized and precision medicine.

A new strategy for the treatment of advanced ovarian cancer: utilizing nanotechnology to regulate the tumor microenvironment

Advanced ovarian cancer (AOC) is prone to recurrence, which can be attributed to drug resistance. Drug resistance may be related to the tumor microenvironment (TME), including the immune and non-immune TME. In the immune TME, the immune effector cells such as dendritic cells (DCs), M1-like tumor-associated macrophages (M1-TAMs), and T cells are inhibited. In contrast, immunosuppressive cells such as M2-like tumor-associated macrophages (M2-TAMs), myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs) are activated. These changes make it difficult to produce immune effects and affect the efficacy of chemo-immunotherapy. In the non-immune TME, mechanisms such as apoptosis inhibition, DNA damage response (DDR), and epithelial-mesenchymal transition (EMT) can promote tumor growth, metastasis, and drug resistance. Despite the challenges posed by the TME in the treatment of AOC, the unique biological advantages of nanoparticles (NPs) make it possible to regulate the TME. NPs can stimulate the immune responses of M1-TAMs, DCs, and T cells while reducing the infiltration of immune suppressive cells such as M2-TAMs and Tregs, thereby regulating the AOC immune TME. In addition, NPs can regulate the non-immune TME by reducing apoptosis in AOC cells, inhibiting homologous recombination (HR) repair, reversing EMT, and achieving the effect of reversing drug resistance. In summary, the application of NPs provides some new venues for clinical treatment in AOC.

Molecular and cellular morphology of placenta unveils new mechanisms of reproductive immunology

INTRODUCTION

Despite of numerous studies of the placenta, some molecular and cellular characteristics, particularly the relationship among different cell types, have not been well understood. We aim to investigate the basic and intricate details of cellular and molecular elements in early and late phase placentas to gain better understanding of the immune regulation of human reproductive process.

METHODS

A novel combination of techniques of spatial transcriptomics(ST), multiple immunohistochemistry, and a dual labeling combining immunohistochemistry and (fluorescence in situ hybridization) FISH on normal and ectopic pregnancy and animal models was employed to investigate the placenta at tissue, cell, protein and molecular levels and to trace the fetal and maternal origin of every cell in early and late placentas.

RESULTS

Original discoveries include early expression of immune checkpoint proteins in embryo trophoblasts even before implantation. The detailed distributional relationships among different cell types of fetal and maternal origins in placenta and decidua indicate an immune rejection of the mother towards the fetus and this was counterbalanced by immune inhibitory proteins and blocking antibody Immunoglobulin G4 (IgG4) at the junction between the fetus and the mother. In contrary to common believe, we found that vascular endothelial and glandular epithelial cells in the decidua remain maternal in origin and were not replaced by fetal cells. At term placenta, fetal immune cells infiltrated into the maternal side of the decidus and vice versa indicating a possible immune reaction between fetal and maternal immune systems and suggesting a possible immune mechanism for trigger of parturition. The ability of trophoblasts to create an immune suppressed environment was also supported by findings in ectopic pregnancy and the animal models.

CONCLUSION

The findings indicate a fetus-driven mechanism of immune balance involving both cellular and humoral immunity in human reproduction.

Progress in understanding the regulatory mechanisms of immune checkpoint proteins PD-1 and PD-L1 expression

Programmed Death Protein-1 (PD-1) is a cell surface receptor that serves as a checkpoint for T cells, playing a pivotal role in regulating T-cell apoptosis. The binding of PD-1 to its ligand, Programmed Death Ligand 1 (PD-L1), inhibits anti-tumor immunity by suppressing T-cell activation signals. Indeed, the PD-1/PD-L1 pathway governs the induction and maintenance of immune tolerance within the tumor microenvironment. Consequently, the regulation of PD-1/PD-L1 immune checkpoint expression is of paramount importance. This review summarizes the mechanisms governing PD1/PD-L1 expression at various stages, including transcription, post-transcription (mRNA processing), and post-translation (protein modifications), as well as immunotherapy targeting PD1/PD-L1, aiming to further explore novel strategies for tumor immunotherapy.

High CD38 expression defines a mitochondrial function-adapted CD8+ T cell subset with implications for lung cancer immunotherapy

Despite identifying specific CD8+ T cell subsets associated with immunotherapy resistance, the molecular pathways driving this process remain elusive. Given the potential role of CD38 in regulating CD8+ T cell function, we aimed to investigate the accumulation of CD38+CD8+ T cells in lung cancer and explore its role in immunotherapy resistance. Phenotypic analysis of tumoral CD8+ T cells from both lung cancer patients and immunotherapy-resistant preclinical models revealed that CD38-expressing CD8+ T cells consist of CD38hi and CD38int subsets. These cells exhibited higher expression of exhaustion markers and displayed dysregulated mitochondrial bioenergetics. Notably, increased levels of CD38hiCD8+ T cells in the peripheral, but not central, tumor microenvironment were associated with a favorable response to anti-PD-1 therapy in non-small-cell lung cancer and correlated with the depth of clinical regression. This was evidenced by the greater depletion of CD38hiCD8+ T cells in patients with higher regional CD38hiCD8+ T cell infiltration. In immune checkpoint blockade (ICB)-resistant murine lung cancer models, PD-L1 mAbs alone failed to effectively reduce CD38hiCD8+ T cell levels. Notably, combination therapy with PD-L1 mAbs and EGCG selectively restricted CD38hiCD8+ T cell infiltration and enhanced IFN-γ production, significantly improving survival in this carcinoma model. The restoration of immunotherapy sensitivity was linked to improved mitochondrial function in CD38hiCD8+ T cells, which was validated by the established relationship between IFN-γ production and mitochondrial metabolism. Collectively, our data highlight the role of CD38-coupled mitochondrial dysfunction in promoting CD8+ T cell exhaustion and intrinsic resistance to ICB therapy, thereby offering a rationale for targeting CD38 to enhance the therapeutic efficacy of PD-1 blockade in lung cancer.

RNA modifications in cancer

RNA modifications are emerging as critical cancer regulators that influence tumorigenesis and progression. Key modifications, such as N6-methyladenosine (m6A) and 5-methylcytosine (m5C), are implicated in various cellular processes. These modifications are regulated by proteins that write, erase, and read RNA and modulate RNA stability, splicing, translation, and degradation. Recent studies have highlighted their roles in metabolic reprogramming, signaling pathways, and cell cycle control, which are essential for tumor proliferation and survival. Despite these scientific advances, the precise mechanisms by which RNA modifications affect cancer remain inadequately understood. This review comprehensively examines the role RNA modifications play in cancer proliferation, metastasis, and programmed cell death, including apoptosis, autophagy, and ferroptosis. It explores their effects on epithelial-mesenchymal transition (EMT) and the immune microenvironment, particularly in cancer metastasis. Furthermore, RNA modifications' potential in cancer therapies, including conventional treatments, immunotherapy, and targeted therapies, is discussed. By addressing these aspects, this review aims to bridge current research gaps and underscore the therapeutic potential of targeting RNA modifications to improve cancer treatment strategies and patient outcomes.

Biomarkers for immunotherapy resistance in non-small cell lung cancer

Immunotherapy has revolutionised the treatment landscape of non-small cell lung cancer (NSCLC), significantly improving survival outcomes and offering renewed hope to patients with advanced disease. However, the majority of patients experience limited long-term benefits from immune checkpoint inhibition (ICI) due to the development of primary or acquired immunotherapy resistance. Accurate predictive biomarkers for immunotherapy resistance are essential for individualising treatment strategies, improving survival outcomes, and minimising potential treatment-related harm. This review discusses the mechanisms underlying resistance to immunotherapy, addressing both cancer cell-intrinsic and cancer cell-extrinsic resistance processes. We summarise the current utility and limitations of two clinically established biomarkers: programmed death ligand 1 (PD-L1) expression and tumour mutational burden (TMB). Following this, we present a comprehensive review of emerging immunotherapy biomarkers in NSCLC, including tumour neoantigens, epigenetic signatures, markers of the tumour microenvironment (TME), genomic alterations, host-microbiome composition, and circulating biomarkers. The potential clinical applications of these biomarkers, along with novel approaches to their biomarker identification and targeting, are discussed. Additionally, we explore current strategies to overcome immunotherapy resistance and propose incorporating predictive biomarkers into an adaptive clinical trial design, where specific immune signatures guide subsequent treatment selection.

KDM5D histone demethylase mediates p38α inactivation via its enzymatic activity to inhibit cancer progression

The p38 MAP kinase (MAPK) signaling pathway plays pivotal roles in various cellular processes. Phosphorylation serves as a canonical way to regulate p38α activation through a phosphorylation cascade. Thus, understanding the mechanism governing p38α phosphorylation is important. The present study demonstrated that p38α undergoes methylation at K165, which promote its phosphorylation in tumor cells. Inhibition of p38α methylation impairs p38α phosphorylation, repressing tumor progression in vitro and in vivo. Mechanistically, KDM5D is a demethylase that interacts with p38α, mediating demethylation at K165 and inhibiting p38α phosphorylation. Moreover, KDM5D is expressed at low levels in non-small cell lung cancer (NSCLC), and high KDM5D expression is positively correlated with cancer survival. KDM5D markedly inhibits cell proliferation and migration via inactivating p38α, thereby slowing cancer progression in xenograft models. In summary, these findings highlight KDM5D as a demethylase of p38α at K165, elucidating a unique role for lysine demethylation in integrating cytoplasmic kinase-signaling cascades. The present results revealed the critical role of KDM5D in suppressing tumor progression, suggesting that KDM5D can serve as a potential drug target for combating hyperactive p38α-driven lung cancer.

Dual impacts of serine/glycine-free diet in enhancing antitumor immunity and promoting evasion via PD-L1 lactylation

The effect of the serine/glycine-free diet (-SG diet) on colorectal cancer (CRC) remains unclear; meanwhile, programmed death-1 (PD-1) inhibitors are less effective for most CRC patients. Here, we demonstrate that the -SG diet inhibits CRC growth and promotes the accumulation of cytotoxic T cells to enhance antitumor immunity. Additionally, we also identified the lactylation of programmed death-ligand 1 (PD-L1) in tumor cells as a mechanism of immune evasion during cytotoxic T cell-mediated antitumor responses, and blocking the PD-1/PD-L1 signaling pathway is able to rejuvenate the function of CD8+ T cells recruited by the -SG diet, indicating the potential of combining the -SG diet with immunotherapy. We conducted a single-arm, phase I study (ChiCTR2300067929). The primary outcome suggests that the -SG diet is feasible and safe for regulating systemic immunity. Secondary outcomes include patient tolerability and potential antitumor effects. Collectively, our findings highlight the promising therapeutic potential of the -SG diet for treating solid tumors.

TIGIT: Will it be the next star therapeutic target like PD-1 in hematological malignancies?

Research on the mechanism and application of checkpoint inhibitory receptors in hematologic diseases has progressed rapidly. However, in the treatment of relapserefractory (R/R) hematologic malignancies and anti-programmed cell death protein 1 (PD-1), patients who are resistant to anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) are in urgent need of alternative therapeutic targets. T cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT) has a broad prospect as an inhibitory receptor like PD-1, but its more specific mechanism of action and application in hematologic diseases still need to be further studied. In this review, we discuss the mechanism of TIGIT pathway, combined effects with other immune checkpoints, immune-related therapy, the impact of TIGIT on hematopoietic stem cell transplantation (HSCT) and the tumor microenvironment (TME) provides a potential therapeutic target for hematologic malignancies.

Methylation modification of non-histone proteins in breast cancer: an emerging targeted therapeutic strategy

Breast cancer is a major public health concern worldwide, being the most commonly diagnosed cancer among women and a leading cause of cancer-related deaths. Recent studies have highlighted the significance of non-histone methylation in breast cancer, which modulates the activity, interaction, localization, and stability of target proteins. This regulation affects critical processes such as oncogenesis, tumor growth, proliferation, invasion, migration, and immune responses. This review delves into the enzymes responsible for non-histone methylation, such as protein arginine methyltransferases (PRMTs), lysine methyltransferases (KMTs), and demethylases, and explores their roles in breast cancer. By elucidating the molecular mechanisms and functional consequences of non-histone methylation, this review aims to provide insights into novel therapeutic strategies targeting these pathways. The therapeutic potential of targeting non-histone methylation to overcome drug resistance and enhance treatment efficacy in breast cancer is also discussed, highlighting promising avenues for future research and clinical applications.

Regulation of post-translational modification of PD-L1 and associated opportunities for novel small-molecule therapeutics

PD-L1 is overexpressed on the surface of tumor cells and binds to PD-1, resulting in tumor immune escape. Therapeutic strategies to target the PD-1/PD-L1 pathway involve blocking the binding. Immune checkpoint inhibitors have limited efficacy against tumors because PD-L1 is also present in the cytoplasm. PD-L1 of post-translational modifications (PTMs) have uncovered numerous mechanisms contributing to carcinogenesis and have identified potential therapeutic targets. Therefore, small molecule inhibitors can block crucial carcinogenic signaling pathways, making them a potential therapeutic option. To better develop small molecule inhibitors, we have summarized the PTMs of PD-L1. This review discusses the regulatory mechanisms of small molecule inhibitors in carcinogenesis and explore their potential applications, proposing a novel approach for tumor immunotherapy based on PD-L1 PTM.

Lysine methylation modifications in tumor immunomodulation and immunotherapy: regulatory mechanisms and perspectives

Lysine methylation is a crucial post-translational modification (PTM) that significantly impacts gene expression regulation. This modification not only influences cancer development directly but also has significant implications for the immune system. Lysine methylation modulates immune cell functions and shapes the anti-tumor immune response, highlighting its dual role in both tumor progression and immune regulation. In this review, we provide a comprehensive overview of the intrinsic role of lysine methylation in the activation and function of immune cells, detailing how these modifications affect cellular processes and signaling pathways. We delve into the mechanisms by which lysine methylation contributes to tumor immune evasion, allowing cancer cells to escape immune surveillance and thrive. Furthermore, we discuss the therapeutic potential of targeting lysine methylation in cancer immunotherapy. Emerging strategies, such as immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell (CAR-T) therapy, are being explored for their efficacy in modulating lysine methylation to enhance anti-tumor immune responses. By targeting these modifications, we can potentially improve the effectiveness of existing treatments and develop novel therapeutic approaches to combat cancer more effectively.

Association of CD8+TILs co-expressing granzyme A and interferon-γ with colon cancer cells in the tumor microenvironment

CD8+T cells secreting granzyme A (GZMA) can induce pyroptosis in tumor cells by effectively cleaving gasdermin B (GSDMB), which is stimulated by interferon-γ (IFN-γ). However, the interaction between GZMA-expressing CD8+T cells and GSDMB-expressing tumor cells in colon cancer remains poorly understood. Our research employed multi-color immunohistochemistry (mIHC) staining and integrated clinical data to explore the spatial distribution and clinical relevance of GZMA- and IFN-γ-expressing CD8+ tumor-infiltrating lymphocytes (TILs), as well as GSDMB-expressing CK+ cells, within the tumor microenvironment (TME) of human colon cancer samples. Additionally, we utilizing single-cell RNA sequencing (scRNA-seq) data to examine the functional dynamics and interactions among these cell populations. scRNA-seq analysis of colorectal cancer (CRC) tissues revealed that CD8+TILs co-expressed GZMA and IFN-γ, but not other cell types. Our mIHC staining results indicated that a significant reduction in the infiltration of GZMA+IFN-γ+CD8+TILs in colon cancer patients (P < 0.01). Functional analysis results indicated that GZMA+IFN-γ+CD8+TILs demonstrated enhanced activation and effector functions compared to other CD8+TIL subsets. Furthermore, GSDMB-expressing CK+ cells exhibited augmented immunogenicity. Correlation analysis highlighted a positive association between GSDMB+CK+ cells and GZMA+IFN-γ+CD8+TILs (r = 0.221, P = 0.033). Analysis of cell-cell interactions further showed that these interactions were mediated by IFN-γ and transforming growth factor-β (TGF-β), the co-stimulatory molecule ICOS, and immune checkpoint molecules TIGIT and TIM-3. These findings suggested that GZMA+IFN-γ+CD8+TILs modulating GSDMB-expressing tumor cells, significantly impacted the immune microenvironment and patients' prognosis in colon cancer. By elucidating these mechanisms, our present study aims to provide novel insights for the advancement of immunotherapeutic strategies in colon cancer.

SETD7 Promotes Cell Proliferation and Migration via Methylation-mediated TAF7 in Clear Cell Renal Cell Carcinoma

SET domain containing 7(SETD7), a member of histone methyltransferases, is abnormally expressed in multiple tumor types. However, the biological function and underlying molecular mechanism of SETD7 in clear cell renal cell carcinoma (ccRCC) remain unclear. Here, we explored the biological effects of SETD7-TAF7-CCNA2 axis on proliferation and metastasis in ccRCC. We identified both SETD7 and TAF7 were up-regulated and significantly promoted the proliferation and migration of ccRCC cells. Concurrently, there was a significant positive correlation between the expression of SETD7 and TAF7, and the two were colocalized in the nucleus. Mechanistically, SETD7 methylates TAF7 at K5 and K300 sites, resulting in the deubiquitination and stabilization of TAF7. Furthermore, re-expression of TAF7 could partially restore SETD7 knockdown inhibited ccRCC cells proliferation and migration. In addition, TAF7 transcriptionally activated to drive the expression of cyclin A2 (CCNA2). And more importantly, the methylation of TAF7 at K5 and K300 sites exhibited higher transcriptional activity of CCNA2, which promotes formation and progression of ccRCC. Our findings reveal a unique mechanism that SETD7 mediated TAF7 methylation in regulating transcriptional activation of CCNA2 in ccRCC progression and provide a basis for developing effective therapeutic strategies by targeting members of SETD7-TAF7-CCNA2 axis.

Treatment-related adverse events of immune checkpoint inhibitors in clinical trials: a systematic review and meta-analysis

Aim

This study comprehensively assesses the incidence and profiles of treatment-related adverse events (trAEs) of immune checkpoint inhibitor (ICI)-based therapies across cancer at various sites.

Methods

We systematically searched the PubMed, Embase, and Cochrane databases for trials investigating ICI-based therapies published between their inception and August 2023.

Results

In total, 147 studies involving 45,855 patients met the inclusion criteria. Among them, patients treated with ICIs reported 39.8% and 14.9% of all-grade and grade ≥3 immune-related adverse events (irAEs), respectively. The most common all-grade irAEs were dermatological and gastrointestinal issues, diarrhea, and pruritus, whereas patients who received ICIs showed most common grade ≥3 irAEs, including gastrointestinal events, diarrhea, increased aspartate aminotransferase and alanine transaminase levels, and hepatic and dermatological events. The overall trAE incidence in patients treated with ICIs was 83.2% for all-grade trAEs and 38.2% for grade ≥3 trAEs. TrAE incidence was highest for patients treated with cytotoxic T lymphocyte antigen-4 inhibitors for all-grade and grade ≥3 trAEs, with incidences of 86.4% and 39.2%, respectively. ICIs combined with targeted therapy showed the highest all-grade and grade ≥3 trAEs, with incidences of 96.3% and 59.4%, respectively. The most common all-grade trAEs were anemia, decrease in white blood cell count, decrease in neutrophil count, nausea, fatigue, diarrhea, and alopecia; patients who received ICIs presented relatively high incidences of grade ≥3 trAEs.

Conclusion

This study provided comprehensive data regarding irAEs and trAEs in patients receiving ICIs. These results should be applied in clinical practice to provide an essential reference for safety profiles of ICIs.

Systematic review registration

INPLASY platform, identifier INPLASY202380119.

Genome-Wide Methylation Analysis in Two Wild-Type Non-Small Cell Lung Cancer Subgroups with Negative and High PD-L1 Expression

We conducted a pilot study to analyze the differential methylation status of 20 primary acinar adenocarcinomas of the lungs. These adenocarcinomas had to be wild type in mutation analysis and had either high (TPS > 50%; n = 10) or negative (TPS < 1%; n = 10) PD-L1 status to be integrated into our study. To examine the methylation of 866,895 specific sites, we utilized the Illumina Infinium EPIC bead chip array. Both hypermethylation and hypomethylation play significant roles in tumor development, progression, and metastasis. They also impact the formation of the tumor microenvironment, which plays a decisive role in tumor differentiation, epigenetics, dissemination, and immune evasion. The gained methylation patterns were correlated with PD-L1 expression. Our analysis has identified distinct methylation patterns in lung adenocarcinomas with high and negative PD-L1 expression. After analyzing the correlation between the methylation results of genes and promoters with their pathobiology, we found that tumors with high expression of PD-L1 tend to exhibit oncogenic effects through hypermethylation. On the other hand, tumors with negative PD-L1 expression show loss of their suppressor functions through hypomethylation. The suppressor functions of hypermethylated genes and promoters are ineffective compared to simultaneously activated dominant oncogenic mechanisms. The tumor microenvironment supports tumor growth in both groups.

LSD2 Is an Epigenetic Player in Multiple Types of Cancer and Beyond

Histone demethylases, enzymes responsible for removing methyl groups from histone proteins, have emerged as critical players in regulating gene expression and chromatin dynamics, thereby influencing various cellular processes. LSD2 and LSD1 have attracted considerable interest among these demethylases because of their associations with cancer. However, while LSD1 has received significant attention, LSD2 has not been recognized to the same extent. In this study, we conduct a comprehensive comparison between LSD2 and LSD1, with a focus on exploring LSD2's implications. While both share structural similarities, LSD2 possesses unique features as well. Functionally, LSD2 shows diverse roles, particularly in cancer, with tissue-dependent roles. Additionally, LSD2 extends beyond histone demethylation, impacting DNA methylation, cancer cell reprogramming, E3 ubiquitin ligase activity and DNA damage repair pathways. This study underscores the distinct roles of LSD2, providing insights into their contributions to cancer and other cellular processes.

Emerging therapeutic frontiers in cancer: insights into posttranslational modifications of PD-1/PD-L1 and regulatory pathways

The interaction between programmed cell death ligand 1 (PD-L1), which is expressed on the surface of tumor cells, and programmed cell death 1 (PD-1), which is expressed on T cells, impedes the effective activation of tumor antigen-specific T cells, resulting in the evasion of tumor cells from immune-mediated killing. Blocking the PD-1/PD-L1 signaling pathway has been shown to be effective in preventing tumor immune evasion. PD-1/PD-L1 blocking antibodies have garnered significant attention in recent years within the field of tumor treatments, given the aforementioned mechanism. Furthermore, clinical research has substantiated the efficacy and safety of this immunotherapy across various tumors, offering renewed optimism for patients. However, challenges persist in anti-PD-1/PD-L1 therapies, marked by limited indications and the emergence of drug resistance. Consequently, identifying additional regulatory pathways and molecules associated with PD-1/PD-L1 and implementing judicious combined treatments are imperative for addressing the intricacies of tumor immune mechanisms. This review briefly outlines the structure of the PD-1/PD-L1 molecule, emphasizing the posttranslational modification regulatory mechanisms and related targets. Additionally, a comprehensive overview on the clinical research landscape concerning PD-1/PD-L1 post-translational modifications combined with PD-1/PD-L1 blocking antibodies to enhance outcomes for a broader spectrum of patients is presented based on foundational research.

Biomarkers predicting the efficacy of immune checkpoint inhibitors in hepatocellular carcinoma

In recent years, immune checkpoint inhibitors (ICIs) have emerged as a transformative approach in treating advanced hepatocellular carcinoma (HCC). Despite their success, challenges persist, including concerns about their effectiveness, treatment costs, frequent occurrence of treatment-related adverse events, and tumor hyperprogression. Therefore, it is imperative to identify indicators capable of predicting the efficacy of ICIs treatment, enabling optimal patient selection to maximize clinical benefits while minimizing unnecessary toxic side effects and economic losses. This review paper categorizes prognostic biomarkers of ICIs treatment into the following categories: biochemical and cytological indicators, tumor-related markers, imaging and personal features, etiology, gut microbiome, and immune-related adverse events (irAEs). By organizing these indicators systematically, we aim to guide biomarker exploration and inform clinical treatment decisions.

Progresses in biomarkers for cancer immunotherapy

Currently, checkpoint inhibitor-based immunotherapy has emerged as prevailing treatment modality for diverse cancers. However, immunotherapy as a first-line therapy has not consistently yielded durable responses. Moreover, the risk of immune-related adverse events increases with combination regimens. Thus, the development of predictive biomarkers is needed to optimize individuals benefit, minimize risk of toxicities, and guide combination approaches. The greatest focus has been on tumor programmed cell death-ligand 1 (PD-L1), microsatellite instability (MSI), and tumor mutational burden (TMB). However, there remains a subject of debate due to thresholds variability and significant heterogeneity. Major unmet challenges in immunotherapy are the discovery and validation of predictive biomarkers. Here, we show the status of tumor PD-L1, MSI, TMB, and emerging data on novel biomarker strategies with oncogenic signaling and epigenetic regulation. Considering the exploration of peripheral and intestinal immunity has served as noninvasive alternative in predicting immunotherapy, this review also summarizes current data in systemic immunity, encompassing solute PD-L1 and TMB, circulating tumor DNA and infiltrating lymphocytes, routine emerging inflammatory markers and cytokines, as well as gut microbiota. This review provides up-to-date information on the evolving field of currently available biomarkers in predicting immunotherapy. Future exploration of novel biomarkers is warranted.

Cancer immunotherapies: advances and bottlenecks

Immunotherapy has ushered in a new era in cancer treatment, and cancer immunotherapy continues to be rejuvenated. The clinical goal of cancer immunotherapy is to prime host immune system to provide passive or active immunity against malignant tumors. Tumor infiltrating leukocytes (TILs) play an immunomodulatory role in tumor microenvironment (TME) which is closely related to immune escape of tumor cells, thus influence tumor progress. Several cancer immunotherapies, include immune checkpoint inhibitors (ICIs), cancer vaccine, adoptive cell transfer (ACT), have shown great efficacy and promise. In this review, we will summarize the recent research advances in tumor immunotherapy, including the molecular mechanisms and clinical effects as well as limitations of immunotherapy.

Development of a Patient-Derived 3D Immuno-Oncology Platform to Potentiate Immunotherapy Responses in Ascites-Derived Circulating Tumor Cells

High-grade serous ovarian cancer (HGSOC) is responsible for the majority of gynecology cancer-related deaths. Patients in remission often relapse with more aggressive forms of disease within 2 years post-treatment. Alternative immuno-oncology (IO) strategies, such as immune checkpoint blockade (ICB) targeting the PD-(L)1 signaling axis, have proven inefficient so far. Our aim is to utilize epigenetic modulators to maximize the benefit of personalized IO combinations in ex vivo 3D patient-derived platforms and in vivo syngeneic models. Using patient-derived tumor ascites, we optimized an ex vivo 3D screening platform (PDOTS), which employs autologous immune cells and circulating ascites-derived tumor cells, to rapidly test personalized IO combinations. Most importantly, patient responses to platinum chemotherapy and poly-ADP ribose polymerase inhibitors in 3D platforms recapitulate clinical responses. Furthermore, similar to clinical trial results, responses to ICB in PDOTS tend to be low and positively correlated with the frequency of CD3+ immune cells and EPCAM+/PD-L1+ tumor cells. Thus, the greatest response observed with anti-PD-1/anti-PD-L1 immunotherapy alone is seen in patient-derived HGSOC ascites, which present with high levels of systemic CD3+ and PD-L1+ expression in immune and tumor cells, respectively. In addition, priming with epigenetic adjuvants greatly potentiates ICB in ex vivo 3D testing platforms and in vivo tumor models. We further find that epigenetic priming induces increased tumor secretion of several key cytokines known to augment T and NK cell activation and cytotoxicity, including IL-6, IP-10 (CXCL10), KC (CXCL1), and RANTES (CCL5). Moreover, epigenetic priming alone and in combination with ICB immunotherapy in patient-derived PDOTS induces rapid upregulation of CD69, a reliable early activation of immune markers in both CD4+ and CD8+ T cells. Consequently, this functional precision medicine approach could rapidly identify personalized therapeutic combinations able to potentiate ICB, which is a great advantage, especially given the current clinical difficulty of testing a high number of potential combinations in patients.

Immune-related adverse events associated with nab-paclitaxel/paclitaxel combined with immune checkpoint inhibitors: a systematic review and network meta-analysis

Objective

The combination of nanoparticle albumin-bound paclitaxel (nab-PTX)/paclitaxel (PTX) with immune checkpoint inhibitors (ICIs) has demonstrated significant efficacy in cancer patients. However, the safety of these combination regimens remains conflicting in former researches. Therefore, in order to address this issue, we performed a systematic review and network meta-analysis (NMA) to evaluate and compare the safety profile.

Methods

We performed a systematic review by searching randomized controlled trials (RCTs) from PubMed, EMBASE, Cochrane Library, ClinicalTrials.gov, and Web of Science up to August 15, 2022. The primary outcomes were all-grade (grade 1-5) and high-grade (grade 3-5) immune-related adverse events (irAEs). Secondary outcomes were all-grade (grade 1-5) and high-grade (grade 3-5) irAEs of subgroups of ICIs.

Results

There were 22 RCTs included in the NMA, involving a total of 15 963 patients diagnosed with any type of cancer. ICIs+nab-PTX was associated with a noticeably decreased risk of grade 3-5 pneumonitis (odds ratio [OR]=0.28, 95% credible interval [CrI]: 0.09,0.90) compared to ICI monotherapy; ICIs+PTX showed a lower risk of grade 1-5 hyperthyroidism (OR=0.46, 95% CrI: 0.22-0.96) and grade 1-5 hypothyroidism (OR=0.49, 95% CrI: 0.26-0.93) than ICIs. Compared with PD-1, PD-1+PTX was associated with a statistically significantly lower risk of grade 1-5 pneumonitis (OR=0.32, 95% CrI: 0.11-0.92). PD-L1 resulted in a noticeably lower risk of grade 1-5 hypothyroidism (OR=0.34, 95% CrI: 0.12-1.00) than PD-L1+PTX. Nearly all treatment regimens containing ICIs demonstrated significantly higher risks of irAEs compared to the standard chemotherapy groups.

Conclusion

Nab-PTX/PTX+ICIs demonstrated an approach leading to decreased risk of irAEs compared with ICI monotherapy. This finding supports that ICIs+nab-PTX/PTX may be a safer treatment strategy. Moreover, we also found that the combination regimens containing ICIs had a higher risk of irAEs than standard chemotherapy. Additionally, ICIs+nab-PTX demonstrated a decreased risk of irAEs compared to ICIs+PTX. PD-1 inhibitors were associated with a higher risk of irAEs than PD-L1 inhibitors.