Targeting Programmed Cell Death -1 (PD-1) and Ligand (PD-L1): A new era in cancer active immunotherapy

DNA damage response-related signatures characterize the immune landscape and predict the prognosis of HCC via integrating single-cell and bulk RNA-sequencing

BACKGROUND

The occurrence and progression of hepatocellular carcinoma (HCC) are significantly affected by DNA damage response (DDR). Exploring DDR-related biomarkers can help predict the prognosis and immune characteristics of HCC.

METHODS

First, the single-cell RNA sequencing (scRNA-seq) dataset GSE242889 was processed and performed manual annotation. Then we found the marker genes of DDR-active subgroups based on "AUCell" algorithm. The "Limma" R package was used to identify differentially expressed genes (DEGs) between tumor and normal samples of HCC. The risk prognostic model was constructed by filtering genes using univariate Cox and LASSO regression analyses. Finally, the signatures were analyzed for immune infiltration, gene mutation, and drug sensitivity. Last but not least, KPNA2, which had the largest coefficient in our model was validated by experiments including western blot, MTT, colony formation and γ-H2AX assays.

RESULTS

We constructed a prognostic model based on 5 DDR marker genes including KIF2C, CDC20, KPNA2, UBE2S and ADH1B for HCC. We also proved that the model had an excellent performance in both training and validation cohorts. Patients in the high-risk group had a poorer prognosis, different immune features, gene mutation frequency, immunotherapy response and drug sensitivity compared with the low-risk group. Besides, our experimental results proved that KPNA2 was up-regulated in liver cancer cells than in hepatocytes. More importantly, the knockdown of KPNA2 significantly inhibited cell variability, proliferation and promoted DNA damage.

CONCLUSIONS

We innovatively integrated scRNA-seq and bulk RNA sequencing to construct the DDR-related prognostic model. Our model could effectively predict the prognosis, immune landscape and therapy response of HCC.

The impact of tertiary lymphoid structures on tumor prognosis and the immune microenvironment in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a common malignancy whose prognosis and treatment outcome are influenced by many factors. Some studies have found that tertiary lymphoid structures (TLSs) in cancer may contribute to prognosis and the prediction of immunotherapy efficacy However, the combined role of TLSs in NSCLC remains unclear. We accessed The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to obtain mRNA sequencing data and clinical information as the TCGA cohort, and used our own sample of 53 advanced NSCLC as a study cohort. The samples were divided into TLS+ and TLS- groups by pathological tissue sections. Patients of the TLS+ group had a better OS (p = 0.022), PFS (p = 0.042), and DSS (p = 0.004) in the TCGA cohort, and the results were confirmed by the study cohort (PFS, p = 0.012). Furthermore, our result showed that the count and size of TLSs are closely associated with the efficacy of immunotherapy. In addition, the TLS+ group was associated with better immune status and lower tumor mutation load. In the tumor microenvironment (TME), the expression levels of CD4+ T cells and CD8+ T cells of different phenotypes were associated with TLSs. Overall, TLSs are a strong predictor of survival and immunotherapeutic efficacy in advanced NSCLC, and T cell-rich TLSs suggest a more ordered and active immune response site, which aids in the decision-making and application of immunotherapy in the clinic.

Fc-Fc interactions and immune inhibitory effects of IgG4: implications for anti-PD-1 immunotherapies

BACKGROUND

The majority of anti-programmed cell-death 1 (PD-1) monoclonal antibodies (mAbs) use S228P mutation IgG4 as the structural basis to avoid the activation of immune cells or complement. However, little attention has been paid to the Fc-Fc interactions between IgG4 and other IgG Fc fragments that could result in adverse effects. Fc-null IgG1 framework is a potential safer alternative to avoid the undesirable Fc-Fc interactions and Fc receptor binding derived effects observed with IgG4. This study provides a comprehensive evaluation of anti-PD-1 mAbs of these two frameworks.

METHODS

Trastuzumab and rituximab (both IgG1), wildtype IgG1 and IgG4 were immobilized on nitrocellulose membranes, coated to microplates and biosensor chips, and bound to tumor cells as targets for Fc-Fc interactions. Wildtype IgG1 and IgG4, anti-PD-1 mAb nivolumab (IgG4 S228P), penpulimab (Fc-null IgG1), and tislelizumab (Fc-null IgG4 S228P-R409K) were assessed for their binding reactions to the immobilized IgG proteins and quantitative kinetic data were obtained. To evaluate the effects of the two anti-PD-1 mAbs on immune responses mediated by trastuzumab and rituximab in the context of combination therapy, we employed classic immune models for antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement dependent cytotoxicity. Tumor-bearing mouse models, both wildtype and humanized, were used for in vivo investigation. Furthermore, we also examined the effects of IgG1 and IgG4 on diverse immune cell populations RESULTS: Experiments demonstrated that wildtype IgG4 and nivolumab bound to immobilized IgG through Fc-Fc interactions, diminishing antibody-dependent cell-mediated cytotoxicity and phagocytosis reactions. Quantitative analysis of kinetic parameters suggests that nivolumab and wildtype IgG4 exhibit comparable binding affinities to immobilized IgG1 in both non-denatured and denatured states. IgG4 exerted inhibitory effects on various immune cell types. Wildtype IgG4 and nivolumab both promoted tumor growth in wildtype mouse models. Conversely, wildtype IgG1, penpulimab, and tislelizumab did not show similar adverse effects.

CONCLUSIONS

Fc-null IgG1 represents a safer choice for anti-PD-1 immunotherapies by avoiding both the adverse Fc-Fc interactions and Fc-related immune inhibitory effects of IgG4. Fc-null IgG4 S228P-R409K and Fc-null IgG1 displayed similar structural properties and benefits. This study contributes to the understanding of immunotherapy resistance and the advancement of safer immune therapies for cancer.

Prognostic Role of OX40, LAG-3, TIM-3 and PD-L1 Expression in Bone and Soft Tissue Sarcomas

Introduction: The current study aims to evaluate the OX40, TIM-3, LAG-3, and PD-L1 targeted pathways in the regulation of T-cell activity in sarcoma patients to determine their relationship with overall survival (OS). Method: This study included one hundred and eleven patients with bone and soft tissue sarcoma diagnosed in two centers between 2010 and 2020. OX40, LAG-3, TIM-3 and PD-L1 expression levels were evaluated immunohistochemically from pathology preparations. Results: PD-L1 staining was detected in tumor cells, OX40, LAG-3, TIM-3 staining was detected in inflammatory cells in tumor tissue. In univariate analysis, no significant relationship was found between OX40, TIM-3, LAG-3, and PD-L1 staining and overall survival (respectively: p = 0.12, p = 0.49, p = 0.31, p = 0.95). When grade and stage at diagnosis, which were found to be significant in univariate analysis, along with OX-40, TIM-3, LAG-3, and PD-L1, were evaluated in multivariate analysis, a positive effect of OX-40 staining on overall survival was determined (p = 0.009). Considering the correlation between PDL-1 and OX40, TIM-3, and LAG-3 staining, a significant positive correlation was found between PDL-1 and TIM-3 and LAG-3 staining (respectively; p = 0.002, p = 0.001). Conclusions: There was no significant relationship between the PDL-1 staining percentage of tumor cells and OX40, TIM-3, and LAG-3 staining in inflammatory cells with the OS of sarcoma patients. However, detecting a significant positive correlation between PDL-1 staining and TIM-3 and LAG-3 staining also holds promise for finding effective targetable combination therapies that can prolong survival in sarcoma patients in the future.

Detailed role of SR-A1 and SR-E3 in tumor biology, progression, and therapy

The first host defense systems are the innate immune response and the inflammatory response. Among innate immune cells, macrophages, are crucial because they preserve tissue homeostasis and eradicate infections by phagocytosis, or the ingestion of particles. Macrophages exhibit phenotypic variability contingent on their stimulation state and tissue environment and may be detected in several tissues. Meanwhile, critical inflammatory functions are played by macrophage scavenger receptors, in particular, SR-A1 (CD204) and SR-E3 (CD206), in a variety of pathophysiologic events. Such receptors, which are mainly found on the surface of multiple types of macrophages, have different effects on processes, including atherosclerosis, innate and adaptive immunity, liver and lung diseases, and, more recently, cancer. Although macrophage scavenger receptors have been demonstrated to be active across the disease spectrum, conflicting experimental findings and insufficient signaling pathways have hindered our comprehension of the molecular processes underlying its array of roles. Herein, as SR-A1 and SR-E3 functions are often binary, either protecting the host or impairing the pathophysiology of cancers has been reviewed. We will look into their function in malignancies, with an emphasis on their recently discovered function in macrophages and the possible therapeutic benefits of SR-A1 and SR-E3 targeting.

Discovery of 4-phenyl-1H-indazole derivatives as novel small-molecule inhibitors targeting the PD-1/PD-L1 interaction

The inhibition of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway with small molecules is a promising approach for cancer immunotherapy. Herein, novel small molecules compounds bearing various scaffolds including thiophene, thiazole, tetrahydroquinoline, benzimidazole and indazole were designed, synthesized and evaluated for their inhibitory activity against the PD-1/PD-L1 interaction. Among them, compound Z13 exhibited the most potent activity with IC50 of 189.6 nM in the homogeneous time-resolved fluorescence (HTRF) binding assay. Surface plasmon resonance (SPR) assay demonstrated that Z13 bound to PD-L1 with high affinity (KD values of 231 nM and 311 nM for hPD-L1 and mPD-L1, respectively). In the HepG2/Jurkat T co-culture cell model, Z13 decreased the viability rate of HepG2 cells in a concentration-dependent manner. In addition, Z13 showed significant in vivo antitumor efficacy (TGI = 52.6 % at 40 mg/kg) without obvious toxicity in the B16-F10 melanoma model. Furthermore, flow cytometry analysis demonstrated that Z13 inhibited tumor growth in vivo by activating the tumor immune microenvironment. These findings indicate that Z13 is a promising PD-1/PD-L1 inhibitor deserving further investigation.

Immune checkpoint inhibitors as the second-line treatment for advanced esophageal squamous cell carcinoma: a cost-effectiveness analysis based on network meta-analysis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have demonstrated superior clinical efficacy in prolonging overall survival (OS) as the second-line treatment for advanced or metastatic esophageal squamous cell carcinoma (ESCC), and were recommended by the guidelines. However, it remains uncertain which ICI is the most cost-effective. This study assessed the cost-effectiveness of ICIs as the second-line treatment for ESCC based on the perspective of the Chinese healthcare system.

METHODS

A network meta-analysis (NMA) was performed to obtain the Hazard ratios (HRs) for indirect comparisons. A three-state Markov model with a 10-year time horizon was conducted to assess the cost-effectiveness. The state transition probabilities were calculated with Kaplan-Meier (KM) curves data from clinical trial and HRs from the NMA. Utilities and costs were derived from local charges or previously published studies. Univariate and probabilistic sensitivity analyses (PSA) were performed to examine model robustness. The results were assessed based on the total costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs).

RESULTS

Five clinical trials (ATTRACTION-3, ESCORT, KEYNOTE-181, ORIENT-2, RATIONALE-302) with a total of 1797 patients were included in the NMA. The NMA showed that both camrelizumab and tislelizumab received relatively high rankings for progression-free survival (PFS) and OS. Compared with sintilimab, treatment with tislelizumab and camrelizumab gained 0.018 and 0.034 additional QALYs, resulting in incremental ICERs of $75,472.65/QALY and $175,681.9/QALY, respectively. Nivolumab and pembrolizumab produced lower QALYs and greater costs, suggesting that both were dominated in comparison to sintilimab. HRs and health state utilities were the most influential parameters in most univariate sensitivity analyses of paired comparisons. PSA results suggested that sintilimab had an 84.4% chance of being the most cost-effective treatment regimen at the WTP threshold of $38,223.34/QALY. In the scenario analysis, sintilimab would no longer be cost-effective, if the price of camrelizumab was assumed to decrease by 64.6% or the price of tislelizumab was assumed to decrease by 16.9%.

CONCLUSIONS AND RELEVANCE

Among the five potential competing ICIs, sintilimab was likely to be the most cost-effective regimen as the second-line treatment for locally advanced or metastatic ESCC in China.

Utilization of Immunotherapy as a Neoadjuvant Therapy for Liver Transplant Recipients with Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is widely recognized as the predominant type of primary liver malignancy. Orthotopic liver transplantation (OLT) has emerged as a highly effective treatment option for unresectable HCC. Immunotherapies as neoadjuvant options are now being actively investigated in the transplant oncology era to enhance outcomes in patients with HCC. Here, we report our experience with patients with HCC who had received Immune Checkpoint Inhibitors (ICPI) prior to curative OLT. Methods: This was a retrospective cohort that included patients with HCC who received ICPI prior to OLT at a single institution from January 2019 to August 2023. Graft rejection was assessed and reported along with the type of ICPI, malignancy treated, and the timing of ICPI in association with OLT. Results: During this cohort period, six patients with HCC underwent OLT after neoadjuvant ICPI. All patients were male with a median age of 61 (interquartile range: 59-64) years at OLT. Etiology associated with HCC was viral (N = 4) or Non-alcoholic steatohepatitis, NASH (N = 2). Tumor focality was multifocal (N = 4) and unifocal (N = 2). Lymphovascular invasion was identified in four patients. No perineural invasion was identified in any of the patients. All patients received ICPI including atezolizumab/bevacizumab (N = 4), nivolumab/ipilimumab (N = 1), and nivolumab as monotherapy (N = 1). All patients received either single or combined liver-directed/locoregional therapy, including transarterial chemoembolization (TACE), Yttrium-90 (Y90), stereotactic body radiotherapy (SBRT), and radiofrequency ablation (RFA). The median washout period was 5 months. All patients responded to ICPI and achieved a safe and successful OLT. All patients received tacrolimus plus mycophenolate as immunosuppressant (IS) therapy post-OLT and one patient received prednisone as additional IS. No patient had clinical evidence of rejection. Conclusions: This cohort emphasizes the success of tumor downstaging by ICPI for OLT when employed as the neoadjuvant therapy strategy. In addition, this study illustrated the importance of timing for the administration of ICPI before OLT. Given the lack of conclusive evidence in this therapeutic area, we believe that our study lays the groundwork for prospective trials to further examine the impact of ICPI prior to OLT.

Plant-derived Durvalumab variants show efficient PD-1/PD-L1 blockade and therapeutically favourable FcR binding

Immune checkpoint blocking therapy targeting the PD-1/PD-L1 inhibitory signalling pathway has produced encouraging results in the treatment of a variety of cancers. Durvalumab (Imfinzi®) targeting PD-L1 is currently used for immunotherapy of several tumour malignancies. The Fc region of this IgG1 antibody has been engineered to reduce FcγR interactions with the aim of enhancing blockade of PD-1/PD-L1 interactions without the depletion of PD-L1-expressing immune cells. Here, we used Nicotiana benthamiana to produce four variants of Durvalumab (DL): wild-type IgG1 and its 'Fc-effector-silent' variant (LALAPG) carrying further modifications to increase antibody half-life (YTE); IgG4S228P and its variant (PVA) with Fc mutations to decrease binding to FcγRI. In addition, DL variants were produced with two distinct glycosylation profiles: afucosylated and decorated with α1,6-core fucose. Plant-derived DL variants were compared to the therapeutic antibody regarding their ability to (i) bind to PD-L1, (ii) block PD-1/PD-L1 inhibitory signalling and (iii) engage with the neonatal Fc receptor (FcRn) and various Fcγ receptors. It was found that plant-derived DL variants bind to recombinant PD-L1 and to PD-L1 expressed in gastrointestinal cancer cells and are able to effectively block its interaction with PD-1 on T cells, thereby enhancing their activation. Furthermore, we show a positive impact of Fc amino acid mutations and core fucosylation on DL's therapeutic potential. Compared to Imfinzi®, DL-IgG1 (LALAPG) and DL-IgG4 (PVA)S228P show lower affinity to CD32B inhibitory receptor which can be therapeutically favourable. Importantly, DL-IgG1 (LALAPG) also shows enhanced binding to FcRn, a key determinant of serum half-life of IgGs.

Molecular insight into T cell exhaustion in hepatocellular carcinoma

Hepatocellular carcinoma is one of the leading causes of cancer-related mortality globally. The emergence of immunotherapy has been shown to be a promising therapeutic approach for hepatocellular carcinoma in recent years. It has been well known that T cell plays a key role in current immunotherapy. However, sustained exposure to antigenic stimulation within the tumor microenvironment may lead to T cell exhaustion, which may cause treatment ineffectiveness. Therefore, reversing T cell exhaustion has been an important issue for the clinical application of immunotherapy, and a comprehensive understanding of the intricacies surrounding T cell exhaustion and its underlying mechanisms is imperative for devising strategies to overcome the T cell exhaustion during treatment. In this review, we summarized the reported drivers of T cell exhaustion in hepatocellular carcinoma and delineate potential ways to reverse it. Additionally, we discussed the interplay among metabolic plasticity, epigenetic regulation, and transcriptional factors in exhausted T cells in hepatocellular carcinoma, and their implication for future clinical applications.

Clinical features and treatment outcomes of PD-1 inhibitor therapy in elderly patients (≥ 65 years) with advanced esophageal squamous cell carcinoma: a real-world study

PURPOSE

This study aims to determine the clinical features and outcomes of PD-1 inhibitor therapy as the initial treatment in patients aged 65 years or older with locally advanced or metastatic esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

The retrospective study conducted a comprehensive analysis of elder patients diagnosed with locally advanced or metastatic ESCC who underwent combined immunochemotherapy in the first affiliated hospital of Nanchang University from January 2019 to January 2023. The main efficacy measures were the objective response rate (ORR) and progression-free survival (PFS). The secondary endpoints were disease control rate (DCR) and overall survival (OS). The evaluation of safety was based on the assessment of adverse events (AEs).

RESULTS

A total of 88 patients were enrolled in the study. All patients received PD-1 inhibitors combined with chemotherapy including taxane and platinum as the first-line treatment. The median PFS was 6.2 months (95% CI: 5.1-7.3), and the median OS was 15.3 months (95% CI: 12.9-17.7). The ORR and DCR were 42.0% and 72.7%, correspondingly. 68 (77.3%) patients experienced treatment-related adverse events (TRAEs) of various degrees, with neutrophil count decreased (21, 23.9%) being the most frequent. TRAEs of grade 3 or 4 occurred in 13 (14.8%) patients.

CONCLUSION

The study demonstrated that individuals older than 65 years with locally advanced or metastatic ESCC have a survival benefit from the first-line treatment of PD-1 inhibitors combined therapy, with a manageable safety profile.

Design, Synthesis, and Evaluation of 8-(o-Tolyl)quinazoline Derivatives as Small-Molecule PD-1/PD-L1 Antagonists

Small-molecule inhibitors targeting programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) interactions can compensate for the shortcomings of antibody-based inhibitors and have attracted considerable attention, some of which have already entered clinical trials. Herein, based on our previous study on small-molecule PD-L1 inhibitors, we reported a series of 8-(o-tolyl)quinazoline derivatives by the skeleton merging strategy. Homogenous time-resolved fluorescence (HTRF) assay against PD-1/PD-L1 interaction identified compound A5, which showed the most potent inhibition with an IC50 value of 23.78 nM. Meanwhile, based on the results of HTRF assay, the structure-activity relationships (SARs) of the tail were focused on. Cell-based PD-1/PD-L1 blockade assay further revealed that A5 significantly blocked the PD-1/PD-L1 interaction at 1.1 μM in the co-culture system of Jurkat-NFAT-PD-1 cells and Hep3B-OS8-hPD-L1 cells with no significant cytotoxicity on Jurkat cells. Moreover, the proposed binding mode of A5 was investigated by a docking analysis. These results indicate that compound A5 is a promising lead compound that deserves further investigation.

Targeted immunotherapy to cancer stem cells: A novel strategy of anticancer immunotherapy

Cancer is a major disease that endangers human health. Cancer drug resistance and relapse are the two main causes contributing to cancer treatment failure. Cancer stem cells (CSCs) are a small fraction of tumor cells that are responsible for tumorigenesis, metastasis, relapse, and resistance to conventional anticancer therapies. Therefore, CSCs are considered to be the root of cancer recurrence, metastasis, and drug resistance. Novel anticancer strategies need to face this new challenge and explore their efficacy against CSCs. Recently, immunotherapy has made rapid advances in cancer treatment, and its potential against CSCs is also an interesting area of research. Meanwhile, immunotherapy strategies are novel therapeutic modalities with promising results in targeting CSCs. In this review, we summarize the targeting of CSCs by various immunotherapy strategies such as monoclonal antibodies(mAb), tumor vaccines, immune checkpoint inhibitors, and chimeric antigen receptor-T cells(CAR-T) in pre-clinical and clinical studies. This review provides new insights into the application of these immunotherapeutic approaches to potential anti-tumor therapies in the future.

Nucleic acid-based small molecules as targeted transcription therapeutics for immunoregulation

Transcription therapy is an emerging approach that centers on identifying the factors associated with the malfunctioning gene transcription machinery that causes diseases and controlling them with designer agents. Until now, the primary research focus in therapeutic gene modulation has been on small-molecule drugs that target epigenetic enzymes and critical signaling pathways. However, nucleic acid-based small molecules have gained popularity in recent years for their amenability to be pre-designed and realize operative control over the dynamic transcription machinery that governs how the immune system responds to diseases. Pyrrole-imidazole polyamides (PIPs) are well-established DNA-based small-molecule gene regulators that overcome the limitations of their conventional counterparts owing to their sequence-targeted specificity, versatile regulatory efficiency, and biocompatibility. Here, we emphasize the rational design of PIPs, their functional mechanisms, and their potential as targeted transcription therapeutics for disease treatment by regulating the immune response. Furthermore, we also discuss the challenges and foresight of this approach in personalized immunotherapy in precision medicine.

Discovery of Highly Potent Small-Molecule PD-1/PD-L1 Inhibitors with a Novel Scaffold for Cancer Immunotherapy

Inhibition of the PD-1/PD-L1 interaction through small-molecule inhibitors is a promising therapeutic approach in cancer immunotherapy. Herein, we utilized BMS-202 as the lead compound to develop a series of novel PD-1/PD-L1 small-molecule inhibitors with a naphthyridin scaffold. Among these compounds, X14 displayed the most potent inhibitory activity for the PD-1/PD-L1 interaction (IC50 = 15.73 nM). Furthermore, X14 exhibited good binding affinity to both human PD-L1 (KD = 14.62 nM) and mouse PD-L1 (KD = 392 nM). In particular, X14 showed favorable pharmacokinetic properties (oral bioavailability, F = 58.0%). In the 4T1 (mouse breast cancer cells) syngeneic mouse model, intragastric administration of X14 at 10 mg/kg displayed significant antitumor efficacy (TGI = 66%). Mechanistic investigations revealed that X14 effectively enhanced T-cell infiltration within the tumor microenvironment. Our study demonstrates that compound X14 exhibits potential as a candidate compound for the development of orally effective small-molecule inhibitors targeting PD-1/PD-L1.

Inhibitory receptors of plasmacytoid dendritic cells as possible targets for checkpoint blockade in cancer

Plasmacytoid dendritic cells (pDCs) are the major producers of type I interferons (IFNs), which are essential to mount antiviral and antitumoral immune responses. To avoid exaggerated levels of type I IFNs, which pave the way to immune dysregulation and autoimmunity, pDC activation is strictly regulated by a variety of inhibitory receptors (IRs). In tumors, pDCs display an exhausted phenotype and correlate with an unfavorable prognosis, which largely depends on the accumulation of immunosuppressive cytokines and oncometabolites. This review explores the hypothesis that tumor microenvironment may reduce the release of type I IFNs also by a more pDC-specific mechanism, namely the engagement of IRs. Literature shows that many cancer types express de novo, or overexpress, IR ligands (such as BST2, PCNA, CAECAM-1 and modified surface carbohydrates) which often represent a strong predictor of poor outcome and metastasis. In line with this, tumor cells expressing ligands engaging IRs such as BDCA-2, ILT7, TIM3 and CD44 block pDC activation, while this blocking is prevented when IR engagement or signaling is inhibited. Based on this evidence, we propose that the regulation of IFN secretion by IRs may be regarded as an "innate checkpoint", reminiscent of the function of "classical" adaptive immune checkpoints, like PD1 expressed in CD8+ T cells, which restrain autoimmunity and immunopathology but favor chronic infections and tumors. However, we also point out that further work is needed to fully unravel the biology of tumor-associated pDCs, the neat contribution of pDC exhaustion in tumor growth following the engagement of IRs, especially those expressed also by other leukocytes, and their therapeutic potential as targets of combined immune checkpoint blockade in cancer immunotherapy.

A combined approach of structure-based virtual screening and NMR to interrupt the PD-1/PD-L1 axis: Biphenyl-benzimidazole containing compounds as novel PD-L1 inhibitors

Immunotherapy has emerged as a game-changing approach for cancer treatment. Although monoclonal antibodies (mAbs) targeting the programmed cell death protein 1/programmed cell death protein 1 ligand 1 (PD-1/PD-L1) axis have entered the market revolutionizing the treatment landscape of many cancer types, small molecules, although presenting several advantages including the possibility of oral administration and/or reduced costs, struggled to enter in clinical trials, suffering of water insolubility and/or inadequate potency compared with mAbs. Thus, the search for novel scaffolds for both the design of effective small molecules and possible synergistic strategies is an ongoing field of interest. In an attempt to find novel chemotypes, a virtual screening approach was employed, resulting in the identification of new chemical entities with a certain binding capability, the most versatile of which was the benzimidazole-containing compound 10. Through rational design, a small library of its derivatives was synthesized and evaluated. The homogeneous time-resolved fluorescence (HTRF) assay revealed that compound 17 shows the most potent inhibitory activity (IC50 ) in the submicromolar range and notably, differently from the major part of PD-L1 inhibitors, exhibits satisfactory water solubility properties. These findings highlight the potential of benzimidazole-based compounds as novel promising candidates for PD-L1 inhibition.

Inhibition of UV-Induced Stress Signaling and Inflammatory Responses in SKH-1 Mouse Skin by Topical Small-Molecule PD-L1 Blockade

The immune checkpoint ligand PD-L1 has emerged as a molecular target for skin cancer therapy and might also hold promise for preventive intervention targeting solar UV light-induced skin damage. In this study, we have explored the role of PD-L1 in acute keratinocytic photodamage testing the effects of small-molecule pharmacological inhibition. Epidermal PD-L1 upregulation in response to chronic photodamage was established using immunohistochemical and proteomic analyses of a human skin cohort, consistent with earlier observations that PD-L1 is upregulated in cutaneous squamous cell carcinoma. Topical application of the small-molecule PD-L1 inhibitor BMS-202 significantly attenuated UV-induced activator protein-1 transcriptional activity in SKH-1 bioluminescent reporter mouse skin, also confirmed in human HaCaT reporter keratinocytes. RT-qPCR analysis revealed that BMS-202 antagonized UV induction of inflammatory gene expression. Likewise, UV-induced cleavage of procaspase-3, a hallmark of acute skin photodamage, was attenuated by topical BMS-202. NanoString nCounter transcriptomic analysis confirmed downregulation of cutaneous innate immunity- and inflammation-related responses, together with upregulation of immune response pathway gene expression. Further mechanistic analysis confirmed that BMS-202 antagonizes UV-induced PD-L1 expression both at the mRNA and protein levels in SKH-1 epidermis. These data suggest that topical pharmacological PD-L1 antagonism using BMS-202 shows promise for skin protection against photodamage.

Hepatocellular carcinoma: signaling pathways, targeted therapy, and immunotherapy

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with a high mortality rate. It is regarded as a significant public health issue because of its complicated pathophysiology, high metastasis, and recurrence rates. There are no obvious symptoms in the early stage of HCC, which often leads to delays in diagnosis. Traditional treatment methods such as surgical resection, radiotherapy, chemotherapy, and interventional therapies have limited therapeutic effects for HCC patients with recurrence or metastasis. With the development of molecular biology and immunology, molecular signaling pathways and immune checkpoint were identified as the main mechanism of HCC progression. Targeting these molecules has become a new direction for the treatment of HCC. At present, the combination of targeted drugs and immune checkpoint inhibitors is the first choice for advanced HCC patients. In this review, we mainly focus on the cutting-edge research of signaling pathways and corresponding targeted therapy and immunotherapy in HCC. It is of great significance to comprehensively understand the pathogenesis of HCC, search for potential therapeutic targets, and optimize the treatment strategies of HCC.

Combination Therapy and Dual-Target Inhibitors Based on LSD1: New Emerging Tools in Cancer Therapy

Lysine specific demethylase 1 (LSD1), a transcriptional modulator that represses or activates target gene expression, is overexpressed in many cancer and causes imbalance in the expression of normal gene networks. Over two decades, numerous LSD1 inhibitors have been reported, especially some of which have entered clinical trials, including eight irreversible inhibitors (TCP, ORY-1001, GSK-2879552, INCB059872, IMG-7289, ORY-2001, TAK-418, and LH-1802) and two reversible inhibitors (CC-90011 and SP-2577). Most clinical LSD1 inhibitors demonstrated enhanced efficacy in combination with other agents. LSD1 multitarget inhibitors have also been reported, exampled by clinical dual LSD1/histone deacetylases (HDACs) inhibitors 4SC-202 and JBI-802. Herein, we present a comprehensive overview of the combination of LSD1 inhibitors with various antitumor agents, as well as LSD1 multitarget inhibitors. Additionally, the challenges and future research directionsare also discussed, and we hope this review will provide new insight into the development of LSD1-targeted anticancer agents.

Immunotherapy for colorectal cancer: Rational strategies and novel therapeutic progress

There are increasing incidences and mortality rates for colorectal cancer in the world. It is common for chemotherapy and radiation given to patients with colorectal cancer to cause toxicities that limit their effectiveness and cause cancer cells to become resistant to these treatments. Additional targeted treatments are needed to improve patient's quality of life and outcomes. Immunotherapy has rapidly emerged as an incredibly exciting and promising avenue for cancer treatment in recent years. This innovative approach provides novel options for tackling solid tumors, effectively establishing itself as a new cornerstone in cancer treatment. Specifically, in the realm of colorectal cancer (CRC), there is great promise in developing new drugs that target immune checkpoints, offering a hopeful and potentially transformative solution. While immunotherapy of CRC has made significant advances, there are still obstacles and limitations. CRC patients have a poor response to treatment because of the immune-suppressing function of their tumor microenvironment (TME). In addition to blocking inhibitory immune checkpoints, checkpoint-blocking antibodies may also boost immune responses against tumors. The review summarizes recent advances in immune checkpoint inhibitors (ICIs) for CRC, including CTLA-4, PD-1, PD-L1, LAG-3, and TIM-3.

Modulation of miR-146b by N6-methyladenosine modification remodels tumor-associated macrophages and enhances anti-PD-1 therapy in colorectal cancer

PURPOSE

MicroRNA-146b (miR-146b) alleviates experimental colitis in mice by mediating macrophage polarization and the release of inflammatory factors. Our goals were to evaluate the antitumor efficacy of miR-146b in colorectal cancer (CRC) and to investigate the underlying mechanisms.

METHODS

We used murine models of CRC to evaluate whether miR-146b influenced the progression of tumors independent of tumor-associated macrophages (TAMs). RNA immunoprecipitation, N6-methyladenosine (m6A) RNA immunoprecipitation and in vitro pri-miRNA processing assays were conducted to examine whether m6A mediates the maturation of pri-miR-146b/miR-146b. In a series of in vitro and in vivo experiments, we further defined the molecular mechanisms of methyltransferase-like 3 (METTL3)/miR-146b-mediated antitumor immunity and its efficacy in combination with anti-PD-1 immunotherapy.

RESULTS

We found that miR-146b deletion supported tumor progression by increasing the number of alternatively activated (M2) TAMs. Mechanistically, the m6A-related "writer" protein METTL3 and "reader" protein HNRNPA2B1 controlled miR-146b maturation by regulating the m6A modification region of pri-miR-146b. Furthermore, miR-146b deletion promoted the polarization of M2-TAMs by enhancing phosphoinositide 3-kinase (PI3K)/AKT signaling, and this effect was mediated by the class IA PI3K catalytic subunit p110β, which reduced T cell infiltration, aggravated immunosuppression and ultimately promoted tumor progression. METTL3 knockdown or miR-146b deletion induced programmed death ligand 1 (PD-L1) production via the p110β/PI3K/AKT pathway in TAMs and consequently augmented the antitumor activity of anti-PD-1 immunotherapy.

CONCLUSIONS

The maturation of pri-miR-146b is m6A-dependent, and miR-146b deletion-mediated TAM differentiation promotes the development of CRC by activating the PI3K/AKT pathway, which induces upregulation of PD-L1 expression, inhibits T cell infiltration into the TME and enhances the antitumor activity of anti-PD-1 immunotherapy. The findings reveal that targeting miR-146b can serve as an adjuvant to anti-PD-1 immunotherapy.

KERS-Inspired Nanostructured Mineral Coatings Boost IFN-γ mRNA Therapeutic Index for Antitumor Immunotherapy

Tumor-associated macrophage (TAM) reprogramming is a promising therapeutic approach for cancer immunotherapy; however, its efficacy remains modest due to the low bioactivity of the recombinant cytokines used for TAM reprogramming. mRNA therapeutics are capable of generating fully functional proteins for various therapeutic purposes but accused for its poor sustainability. Inspired by kinetic energy recovery systems (KERS) in hybrid vehicles, a cytokine efficacy recovery system (CERS) is designed to substantially augment the therapeutic index of mRNA-based tumor immunotherapy via a "capture and stabilize" mechanism exerted by a nanostructured mineral coating carrying therapeutic cytokine mRNA. CERS remarkably recycles nearly 40% expressed cytokines by capturing them onto the mineral coating to extend its therapeutic timeframe, further polarizing the macrophages to strengthen their tumoricidal activity and activate adaptive immunity against tumors. Notably, interferon-γ (IFN-γ) produced by CERS exhibits ≈42-fold higher biological activity than recombinant IFN-γ, remarkably decreasing the required IFN-γ dosage for TAM reprogramming. In tumor-bearing mice, IFN-γ cmRNA@CERS effectively polarizes TAMs to inhibit osteosarcoma progression. When combined with the PD-L1 monoclonal antibody, IFN-γ cmRNA@CERS significantly boosts antitumor immune responses, and substantially prevents malignant lung metastases. Thus, CERS-mediated mRNA delivery represents a promising strategy to boost antitumor immunity for tumor treatment.

TH-302-loaded nanodrug reshapes the hypoxic tumour microenvironment and enhances PD-1 blockade efficacy in gastric cancer

BACKGROUND

Hypoxia, a common characteristic of the tumour microenvironment, is involved in tumour progression and immune evasion. Targeting the hypoxic microenvironment has been implicated as a promising antitumour therapeutic strategy. TH-302 can be selectively activated under hypoxic conditions. However, the effectiveness of TH-302 in gastric cancer combined immunotherapy remains unclear.

METHODS

We designed mPEG-PLGA-encapsulated TH-302 (TH-302 NPs) to target the hypoxic area of tumour tissues. A particle size analyzer was used to measure the average size and zeta potential of TH-302 NPs. The morphology was observed by transmission electron microscopy and scanning electron microscopy. The hypoxic area of tumour tissues was examined by immunofluorescence assays using pimonidazole. Flow cytometry analysis was performed to measure the levels of TNF-α, IFN-γ, and granzyme B. The synergistic antitumour activity of the combination of TH-302 NPs with anti-PD-1 (α-PD-1) therapy was assessed in vitro and in vivo. Haematoxylin and eosin staining of major organs and biochemical indicator detection were performed to investigate the biological safety of TH-302 NPs in vivo.

RESULTS

TH-302 NPs inhibited the proliferation and promoted the apoptosis of gastric cancer cells under hypoxic conditions. In vitro and in vivo experiments confirmed that TH-302 NPs could effectively alleviate tumour hypoxia. TH-302 NPs exhibited high bioavailability, effective tumour-targeting ability and satisfactory biosafety. Moreover, the combination of TH-302 NPs with α-PD-1 significantly improved immunotherapeutic efficacy in vivo. Mechanistically, TH-302 NPs reduced the expression of HIF-1α and PD-L1, facilitated the infiltration of CD8+ T cells and increased the levels of TNF-α, IFN-γ, and granzyme B in tumours, thereby enhancing the efficacy of α-PD-1 therapy.

CONCLUSION

TH-302 NPs alleviated the hypoxic tumour microenvironment and enhanced the efficacy of PD-1 blockade. Our results provide evidence that TH-302 NPs can be used as a safe and effective nanodrug for combined immunotherapy in gastric cancer treatment.

Mesothelin-targeted CAR-T therapy combined with irinotecan for the treatment of solid cancer

BACKGROUND

Chimeric antigen receptor (CAR) T cell therapy has shown promising results in treating blood cancers, but it has limited efficacy against solid tumors that express mesothelin (MSLN). One of the reasons is the immunosuppressive tumor microenvironment, which consists of physical barriers, multiple mechanisms of immune evasion, and various biochemical factors that favor tumor growth and survival. These factors reduce the antitumor activity of MSLN-targeted CAR T cells in clinical trials. Therefore, new therapeutic strategies are needed to enhance the effectiveness of MSLN-targeted CAR T cell therapy.

METHODS

To investigate whether the antitumor efficacy of anti-MSLN CAR-T cells depends on the epitopes they recognize, we generated MSLN-targeted CAR T cells that bind to different regions of MSLN (Region I, II, III and Full length). We then evaluated the antitumor activity of MSLN-targeted CAR T cells alone or in combination with the chemotherapeutic drug irinotecan or an anti-PD-1 antibody in vitro and in vivo.

RESULTS

We found that MSLN-targeted CAR T cells effectively killed MSLN-positive cancer cells (H9, H226 and Panc-1), but not MSLN-negative cells (A431) in vitro. In a mouse model of H9 tumor xenografts, all CAR T cells showed similar tumor suppression, but an MSLN-targeted scFv with Region I epitope, R47, performed slightly better. Combining irinotecan with CAR_R47 T cells enhanced tumor control synergistically in both H9 xenograft mice and patient-derived xenograft mice.

CONCLUSIONS

Our results suggest that irinotecan can enhance the antitumor activity of MSLN-targeted CAR T cells, and offer a promising combination therapy strategy for MSLN-positive solid tumors.

Small molecules targeting protein-protein interactions for cancer therapy

Protein-protein interactions (PPIs) are fundamental to many biological processes that play an important role in the occurrence and development of a variety of diseases. Targeting the interaction between tumour-related proteins with emerging small molecule drugs has become an attractive approach for treatment of human diseases, especially tumours. Encouragingly, selective PPI-based therapeutic agents have been rapidly advancing over the past decade, providing promising perspectives for novel therapies for patients with cancer. In this review we comprehensively clarify the discovery and development of small molecule modulators of PPIs from multiple aspects, focusing on PPIs in disease, drug design and discovery strategies, structure-activity relationships, inherent dilemmas, and future directions.

Paeoniflorin inhibits hepatocellular carcinoma growth by reducing PD-L1 expression

Abnormal expression of programmed death-ligand 1 (PD-L1) on cancer cells contributes to immune escape in hepatocellular carcinoma (HCC). Paeoniflorin has been shown to inhibit the growth of HCC; however, whether its inhibitory effect involves reducing PD-L1 expression on HCC cells remains unknown. We investigated the antitumor effects of paeoniflorin and its potential regulatory mechanisms in HCC. The effects of paeoniflorin on tumor growth and tumor immunity were determined in H22-xenografted mice and DEN-induced HCC rats. Small interfering RNA against suppressor of cytokine signaling 3 (SOCS3) was transfected into HepG2 cells to verify the effect of paeoniflorin on the SOCS3/signal transducer and activator of transcription 3 (STAT3)/PD-L1signaling pathway. The levels of SOCS3/STAT3/PD-L1 signaling pathway-related mRNAs and proteins were determined by real time-polymerase chain reaction and western blotting, respectively. Interleukin-2 (IL-2), interferon-γ (IFN-γ), granzyme B (GrB), and perforin 1 (PRF1) levels were detected in an H22 and mouse T cell co-culture system. Paeoniflorin can trigger T cell-mediated anti-tumor immune responses by increasing CD8+ T cell counts in tumor tissues, thereby inhibiting tumor growth. Moreover, paeoniflorin increased IL-2, IFN-γ, GrB, and PRF1 levels in the co-culture system. PD-L1 expression was suppressed by paeoniflorin, and this effect was mediated by the SOCS3/STAT3 signaling pathway. Paeoniflorin might thus act via enhancing SOCS3 to inhibit STAT3/PD-L1 signaling and subsequently restore T cell sensitivity to kill tumor cells. Our findings provide novel insights into the anticancer effects of paeoniflorin.

Prognostic value of soluble programmed cell death ligand-1 (sPD-L1) in lymphoma: a systematic review and meta-analysis

Previous studies on the prognostic value of soluble programmed cell death ligand 1 (sPD-L1) in lymphoma patients have yielded inconsistent results. Here, we conducted a meta-analysis and systematic review to investigate the prognostic significance of sPD-L1 in lymphoma, especially in diffuse large B-cell lymphoma (DLBCL) and NK/T-cell lymphoma (NK/TCL). A total of 11 studies with 1185 patients were included in the meta-analysis, and the combined results indicated that high sPD-L1 levels were associated with worse overall survival (OS) (HR = 2.27, 95%CI: 1.70-3.04) and progression-free survival (PFS) (HR = 2.68, 95%CI: 1.92-3.75). Furthermore, subgroup analysis showed that sPD-L1 remained a significant prognostic factor for OS. The meta-analysis indicated that sPD-L1 may be a potential prognostic biomarker for lymphoma, especially in DLBCL and NK/TCL, and high sPD-L1 levels were associated with worse survival prognosis.

PD-L1/BTLA Checkpoint Axis Exploited for Bacterial Immune Escape by Restraining CD8+ T Cell-Initiated Adaptive Immunity in Zebrafish

Programmed death-ligand 1/programmed cell death 1 (PD-L1/PD-1) is one of the most important immune checkpoints in humans and other mammalian species. However, the occurrence of the PD-L1/PD-1 checkpoint in evolutionarily ancient vertebrates remains elusive because of the absence of a PD-1 homolog before its appearance in tetrapods. In this article, we identified, to our knowledge, a novel PD-L1/B and T lymphocyte attenuator (BTLA) checkpoint in zebrafish by using an Edwardsiella tarda-induced bacterial infection model. Results showed that zebrafish (Danio rerio) PD-L1 (DrPD-L1) and BTLA (DrBTLA) were differentially upregulated on MHC class II+ macrophages (Mϕs) and CD8+ T cells in response to E. tarda infection. DrPD-L1 has a strong ability to interact with DrBTLA, as shown by the high affinity (KD = 5.68 nM) between DrPD-L1/DrBTLA proteins. Functionally, the breakdown of DrPD-L1/DrBTLA interaction significantly increased the cytotoxicity of CD8+BTLA+ T cells to E. tarda-infected PD-L1+ Mϕ cells and reduced the immune escape of E. tarda from the target Mϕ cells, thereby enhancing the antibacterial immunity of zebrafish against E. tarda infection. Similarly, the engagement of DrPD-L1 by soluble DrBTLA protein diminished the tolerization of CD8+ T cells to E. tarda infection. By contrast, DrBTLA engagement by a soluble DrPD-L1 protein drives aberrant CD8+ T cell responses. These results were finally corroborated in a DrPD-L1-deficient (PD-L1-/-) zebrafish model. This study highlighted a primordial PD-L1/BTLA coinhibitory axis that regulates CD8+ T cell activation in teleost fish and may act as an alternative to the PD-L1/PD-1 axis in mammals. It also revealed a previously unrecognized strategy for E. tarda immune evasion by inducing CD8+ T cell tolerance to target Mϕ cells through eliciting the PD-L1/BTLA checkpoint pathway.

Tislelizumab Plus Chemotherapy Versus Placebo Plus Chemotherapy as First-Line Treatment for Chinese Patients with Advanced Esophageal Squamous Cell Carcinoma: A Cost-Effectiveness Analysis

BACKGROUND AND OBJECTIVES

Advanced esophageal squamous cell carcinoma (ESCC) is a prevalent and highly malignant tumor with a poor prognosis. Recently, the RATIONALE-306 trial demonstrated that tislelizumab combined with chemotherapy provided overall survival benefits for these patients. This study aimed to assess the cost-effectiveness of this treatment approach in Chinese patients with advanced ESCC from the perspective of healthcare system.

METHODS

A Markov model was constructed to assess the economic and health benefits associated with tislelizumab plus chemotherapy over a 10-year lifetime horizon, utilizing data from the RATIONALE-306 trial. The analysis encompassed the calculation of several key parameters, including the incremental cost-effectiveness ratio (ICER), total cost, incremental cost, total effectiveness, and incremental effectiveness. Tislelizumab was considered cost-effective if the ICER obtained was below the willingness-to-pay (WTP) threshold of US$38,223 per quality-adjusted life-year (QALY); otherwise, it would be deemed not cost-effective. To ensure the robustness of the findings, the results were subjected to one-way sensitivity analysis and probabilistic sensitivity analysis (PSA).

RESULTS

In the base-case analysis, the incremental effectiveness and cost associated with tislelizumab plus chemotherapy, compared to chemotherapy alone, were determined to be 0.40 QALY and US$7604, respectively. This resulted in an ICER of US$18,846 per QALY, which is below the WTP threshold of US$38,223 per QALY. Furthermore, the results from the one-way sensitivity analysis and PSA indicated robustness of the findings.

CONCLUSION

Our lifetime simulation study demonstrated that, in the case of advanced ESCC, the combination of tislelizumab and chemotherapy offers increased effectiveness compared to chemotherapy alone, albeit at a higher cost. Moreover, considering the current WTP threshold in China, the addition of tislelizumab to chemotherapy is considered a cost-effective approach.

Oncolytic Virus Engineering and Utilizations: Cancer Immunotherapy Perspective

Oncolytic viruses have positively impacted cancer immunotherapy over the past 20 years. Both natural and genetically modified viruses have shown promising results in treating various cancers. Various regulatory authorities worldwide have approved four commercial oncolytic viruses, and more are being developed to overcome this limitation and obtain better anti-tumor responses in clinical trials at various stages. Faster advancements in translating research into the commercialization of cancer immunotherapy and a comprehensive understanding of the modification strategies will widen the current knowledge of future technologies related to the development of oncolytic viruses. In this review, we discuss the strategies of virus engineering and the progress of clinical trials to achieve virotherapeutics.

Theoretical and experimental studies on the interaction of biphenyl ligands with human and murine PD-L1: Up-to-date clues for drug design

Today it is widely recognized that the PD-1/PD-L1 axis plays a fundamental role in escaping the immune system in cancers, so that anti-PD-1/PD-L1 antibodies have been evaluated for their antitumor properties in more than 1000 clinical trials. As a result, some of them have entered the market revolutionizing the treatment landscape of specific cancer types. Nonetheless, a new era based on the development of small molecules as anti PD-L1 drugs has begun. There are, however, some limitations to advancing these compounds into clinical stages including the possible difficulty in counteracting the PD-1/PD-L1 interaction in vivo, the discrepancy between the in vitro IC₅₀ (HTFR assay) and cellular EC₅₀ (immune checkpoint blockade co-culture assay), and the differences in ligands' affinity between human and murine PD-L1, which can affect their preclinical evaluation. Here, an extensive theoretical study, assisted by MicroScale Thermophoresis binding assays and NMR experiments, was performed to provide an atomistic picture of the binding event of three representative biphenyl-based compounds in both human and murine PD-L1. Structural determinants of the species' specificity were unraveled, providing unprecedented details useful for the design of next generation anti-PD-L1 molecules.

Fecal microbiota transplantation and its repercussions in patients with melanoma refractory to anti-PD-1 therapy: scope review

INTRODUCTION

despite being extremely effective in some cases, up to 70% of patients with melanoma do not respond to anti-PD-1/PD-L1 (primary resistance) and many of the responders eventually progress (secondary resistance). Extensive efforts are being made to overcome this resistance through new strategies, especially aimed at modulating the intestinal microbiota.

OBJECTIVE

to assess whether fecal microbiota transplantation (FMT), associated with immunotherapy, is beneficial in the clinical course of patients with refractory melanoma.

METHODS

this is a scope review, based on studies collected on the MEDLINE, ScienceDirect, The Cochrane Library, Embase and BMJ Journals; using the terms: "Antibodies, Monoclonal"; "Drug Resistance, Neoplasm"; "Fecal Microbiota Transplantation"; "Host Microbial Interactions"; "Immunotherapy"; "Melanoma"; and "Microbiota". Clinical trials, in English, with relevant data on the subject and fully available were included. A cut-off period was not determined, due to the limited amount of evidence on the topic.

RESULTS

crossing the descriptors allowed the identification of 342 publications and, after applying the eligibility criteria, allowed the selection of 4 studies. From the analyses, it was observed that a considerable part of those studied overcame resistance to immune checkpoint inhibitors after FMT, with better response to treatment, less tumor growth and increased beneficial immune response.

CONCLUSION

it is noted that FMT favors the response of melanoma to immunotherapy, translated into significant clinical benefit. However, further studies are necessary for the complete elucidation of the bacteria and the mechanisms involved, as well as for the translation of new evidence to oncological care practice.

Redox Signaling Modulates Activity of Immune Checkpoint Inhibitors in Cancer Patients

Although immunotherapy is already a staple of cancer care, many patients may not benefit from these cutting-edge treatments. A crucial field of research now focuses on figuring out how to improve treatment efficacy and assess the resistance mechanisms underlying this uneven response. For a good response, immune-based treatments, in particular immune checkpoint inhibitors, rely on a strong infiltration of T cells into the tumour microenvironment. The severe metabolic environment that immune cells must endure can drastically reduce effector activity. These immune dysregulation-related tumour-mediated perturbations include oxidative stress, which can encourage lipid peroxidation, ER stress, and T regulatory cells dysfunction. In this review, we have made an effort to characterize the status of immunological checkpoints, the degree of oxidative stress, and the part that latter plays in determining the therapeutic impact of immunological check point inhibitors in different neoplastic diseases. In the second section of the review, we will make an effort to assess new therapeutic possibilities that, by affecting redox signalling, may modify the effectiveness of immunological treatment.

HUVECs affect HuT-78 cell apoptosis and cytokine production via the HIF-1α-PD-L1/PD-1 pathway under hypoxia

We investigated whether human umbilical vein endothelial cells (HUVECs) under hypoxic conditions can suppress the production of cytokines in Hut-78 cells via the HIF-1α/PD-L1/PD-1 pathway, and the intervention effect of Nivolumab. HUVECs and HuT-78 cells were monocultured or cocultured in a tri-gas incubator with or without Nivolumab pretreatment. Real-time PCR, western blotting, and protein chips were used. Transcriptional regulation of PD-L1 and PD-1 by HIF-1α was analyzed by ChIP-qPCR and luciferase reporter gene assays. Apoptosis was assessed by flow cytometry. In HuT-78 cells, hypoxic monoculture significantly increased the expression of HIF-1α, PD-1, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, IFN-α, and Bax, decreased the expression of Bcl-2, and resulted in increased apoptosis. In comparison to hypoxic monoculture, hypoxic coculture significantly reduced the expression of IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, and IFN-α, as well as Bcl-2, in HuT-78 cells. Meanwhile, Bax expression was significantly increased with elevated apoptosis in HuT-78 cells. However, pretreatment with Nivolumab significantly antagonized the reduction in cytokines and the elevation in apoptosis in HuT-78 cells. Chip-qPCR and luciferase reporter gene assays demonstrated that hypoxia significantly increased the binding of HIF-1α to the upstream regulatory regions of PD-1 at -63 and -66 bp and PD-L1 at -571 bp, promoting their transcription. Therefore, HUVECs under hypoxia can reduce cytokine production and inhibit their own apoptosis in co-culture with HuT-78 cells via the HIF-1α/PD-L1/PD-1 pathway. These findings provide new clues for exploring the combined use of immune checkpoint inhibitors and anti-angiogenic drugs in clinical settings.

Cuproptosis: mechanisms and links with cancers

Cuproptosis was a copper-dependent and unique kind of cell death that was separate from existing other forms of cell death. The last decade has witnessed a considerable increase in investigations of programmed cell death, and whether copper induced cell death was an independent form of cell death has long been argued until mechanism of cuproptosis has been revealed. After that, increasing number of researchers attempted to identify the relationship between cuproptosis and the process of cancer. Thus, in this review, we systematically detailed the systemic and cellular metabolic processes of copper and the copper-related tumor signaling pathways. Moreover, we not only focus on the discovery process of cuproptosis and its mechanism, but also outline the association between cuproptosis and cancers. Finally, we further highlight the possible therapeutic direction of employing copper ion ionophores with cuproptosis-inducing functions in combination with small molecule drugs for targeted therapy to treat specific cancers.

The establishment of B cell-deficient Igh-J KO mouse model by gene editing and efficacy evaluation

Over the last few years, immunotherapy has made significant progress in treating various cancers with therapeutic antibodies. However, therapeutic antibodies have been validated for inducing an unintended immune response in human and animal models, which leads to the emergence of anti-drug antibodies (ADAs) and affects their effectiveness and safety. In preclinical research, ADAs production by B cells may accelerate antibody metabolism and result in missing potential candidate molecules. Thus, it is urgent to develop preclinical models that remove only B cells without affecting the function of T and NK cells. Rearrangement of immunoglobulin heavy chain J gene fragment (Igh-J) is the first link in B cell development, and immunotherapies are currently leaning toward combination treatments with PD-1/PD-L1 antibodies, here we created humanized PD-1, PD-L1 and Igh-J knockout (hPD-1/hPD-L1, Igh-J KO) mice and validated by using the reported high immunogenicity drug M7824 (a protein designed to simultaneously block PD-L1 and TGF-β pathways, poorly anti-tumor efficacy in immunocompetent mice). Phenotypic analysis revealed that human PD-1 and PD-L1 were detectable in hPD-1/hPD-L1, Igh-J KO mice, but not mouse IgM and IgD. Igh-J KO depleted B cells while increased the percentage of other immune cell types. Meanwhile, the humanization of PD-1/PD-L1 and Igh-J KO had neither effect on the overall development, differentiation, or distribution of T cell subtypes, nor on the activation of NK and T cells, indicating that mice can be used for T and NK-related immunotherapies. Furthermore, M7824 treatment of these B cell-deficient mice inhibited tumor growth significantly, with higher M7824 analog concentrations and lower ADA-positive rates. These findings demonstrate that Igh-J KO mice are an effective and stable preclinical model for testing drugs based on T and NK cells with high immunogenicity in vivo.

Immunostimulatory oncolytic activity of coxsackievirus A11 in human malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive solid cancer with a poor prognosis, whereas coxsackievirus A11 (CVA11) is a potential oncolytic virus for cancer treatment. We here investigated the oncolytic activity of CVA11 with human MPM cell lines. CVA11 infection was cytotoxic in all six MPM cell lines examined and showed no or minimal cytotoxicity toward normal human normal cell lines. MPM cells with a higher surface level of intercellular adhesion molecule-1 (ICAM-1) expression tended to be more susceptible to CVA11-induced cytotoxicity, and a neutralizing antibody to ICAM-1 attenuated such cytotoxicity. CVA11 infection activated signaling by Akt and extracellular signal-regulated kinase (ERK) pathways, and inhibitors of such signaling also abrogated CVA11-mediated cytotoxicity. Furthermore, CVA11 infection-triggered multiple modes of tumor cell death including apoptosis, pyroptosis, and necroptosis, and such death was accompanied by the release or exposure of the proinflammatory cytokine interleukin-1β and damage-associated molecular patterns such as calreticulin, high-mobility group box-1, annexin A1, and heat shock protein 70, which are hallmarks of immunogenic cell death. Notably, in vivo treatment of human MPM xenografts with intratumoral CVA11 injection resulted in significant suppression of tumor growth in SCID mice, and all mice infected with CVA11 showed no significant change in body weight. Our findings collectively suggest that the oncolytic activity of CVA11 for MPM is dependent on ICAM-1 as a virus receptor, as well as on Akt and ERK signaling, and that oncolytic virotherapy with CVA11 is a promising treatment modality with immunostimulatory activity for human MPM.

Comprehensive analysis of the role of ICOS ( CD278 ) in pan-cancer prognosis and immunotherapy

BACKGROUND

The immunological checkpoint known as Inducible T Cell Costimulatory Factor (ICOS, Cluster of Differentiation, CD278) is activated and expressed on T cells. Both somatic cells and antigen-presenting cells expressed its ligand, ICOSL (including tumor cells in the tumor microenvironment).It is important for immunosuppression. Uncertainty surrounds the function of ICOS in tumor immunity.

METHODS

Several bioinformatics techniques were employed by us to thoroughly examine the expression and prognostic value of ICOS in 33 cancers based on data collected from TCGA and GTEx. In addition, ICOS was explored with pathological stage, tumor-infiltrating cells, immune checkpoint genes, mismatch repair (MMR) genes, DNA methyltransferases (DNMTs), microsatellite instability (MSI),and tumor mutation burden (TMB).In addition,To ascertain the level of ICOS expression in various cells, qRT-PCR was employed.

RESULTS

The findings revealed that ICOS expression was up regulation in most cancer types. The high expression of ICOS in tumor samples was related to the poor prognosis of UVM and LGG; The positive prognosis was boosted by the strong expression of ICOS in OV, SARC, SKCM, THYM, UCEC, and HNSC. The result is that the expression of malignancy was revealed by the immune cells' invasion.profile of ICOS in different types of cancer. Different ways that ICOS expression is connected to immune cell infiltration account for variations in patient survival. Additionally, the TMB, MSI, MMR, and DNMT genes as well as ICOS expression are linked in many cancer types.The results of PCR showed that it is highly expressed in gastric, breast, liver and renal cell carcinoma cell lines compared with normal cells.

CONCLUSION

This study suggests that ICOS may be a potential tumor immunotherapy target and prognostic marker.

Identification on surrogating overall survival with progression-free survival of first-line immunochemotherapy in advanced esophageal squamous cell carcinoma-an exploration of surrogate endpoint

BACKGROUND

Overall survival (OS) is the gold standard to assess novel therapeutics to treat cancer. However, to identify early efficacy and speed up drug approval, trials have used progression-free survival (PFS) as a surrogate endpoint (SE). Herein, we aimed to examine if PFS could function as an OS surrogate in advanced Esophageal Squamous Cell Carcinoma (ESCC) treated with first-line immunochemotherapy.

METHODS

Two hundred ninety-two advanced ESCC patients treated using inhibitors of PD-1/PD-L1 + chemotherapy or chemotherapy alone were collected. In addition, six phase III randomized clinical trials were eligible for inclusion. Bayesian normal-induced-copula-estimation model in retrospective patient data and regression analysis in the published trial data were used to determine the PFS-OS correlation.

RESULTS

PFS correlated moderately with OS in the retrospective cohort (Kendall's Tau = 0.684, τ = 0.436). In trial-level, treatments effects for PFS correlated weakly with those for OS in intention-to-treat population (R² = 0.436, adj.R² = 0.249, P > 0.05) and in PD-L1-enriched population (R² = 0.072). In arm-level, median PFS also correlated weakly with median OS. Moreover, analysis of the retrospective cohort demonstrated that the annual death risk after progression in the continued immunotherapy group was considerably lower than that in the discontinued group.

CONCLUSION

In trials of anti-PD-1 agents to treat advanced ESCC, the current results provide only weak support for PFS as an OS surrogate; OS cannot be substituted completely by PFS in these cases. The results also suggest that qualified patients with advanced ESCC might benefit from continuous immunotherapy beyond progression to achieve a decreased risk of death.

Targeting ubiquitin-specific protease 8 sensitizes anti-programmed death-ligand 1 immunotherapy of pancreatic cancer

Programmed death-1 (PD-1) and its ligand programmed death-ligand 1 (PD-L1) help tumor cells evade immune surveillance, and are regarded as important targets of anti-tumor immunotherapy. Post-translational modification of PD-L1 has potential value in immunosuppression. Here, we identified that ubiquitin-specific protease 8 (USP8) deubiquitinates PD-L1. Pancreatic cancer tissues exhibited significantly increased USP8 levels compared with those in normal tissues. Clinically, the expression of USP8 showed a significant association with the tumor-node-metastasis stage in multiple patient-derived cohorts of pancreatic cancer. Meanwhile, USP8 deficiency could reduce tumor invasion and migration and tumor size in an immunity-dependent manner, and improve anti-tumor immunogenicity. USP8 inhibitor pretreatment led to reduced tumorigenesis and immunocompetent mice with Usp8 knockdown tumors exhibited extended survival. Moreover, USP8 interacted positively with PD-L1 and upregulated its expression by inhibiting the ubiquitination-regulated proteasome degradation pathway in pancreatic cancer. Combination therapy with a USP8 inhibitor and anti-PD-L1 effectively suppressed pancreatic tumor growth by activation of cytotoxic T-cells and the anti-tumor immunity was mainly dependent on the PD-L1 pathway and CD8 + T cells. Our findings highlight the importance of targeting USP8, which can sensitize PD-L1-targeted pancreatic cancer to immunotherapy and might represent a novel therapeutic strategy to treat patients with pancreatic tumors in the future.

Identification and development of a novel risk model based on cuproptosis-associated RNA methylation regulators for predicting prognosis and characterizing immune status in hepatocellular carcinoma

BACKGROUND

Cuproptosis, a novel cell death caused by excess copper, is quite obscure in hepatocellular carcinoma (HCC) and needs more investigation.

METHODS

RNA-seq and clinical data of HCC patients TCGA database were analyzed to establish a predictive model through LASSO Cox regression analysis. External dataset ICGC was used for the verification. GSEA and CIBERSORT were applied to investigate the molecular mechanisms and immune microenvironment of HCC. Cuproptosis induced by elesclomol was confirmed via various in vitro experiments. The expression of prognostic genes was verified in HCC tissues using qRT-PCR analysis.

RESULTS

Initially, 18 cuproptosis-associated RNA methylation regulators (CARMRs) were selected for prognostic analysis. A nine-gene signature was created by applying the LASSO Cox regression method. Survival and ROC assays were carried out to validate the model using TCGA and ICGC database. Moreover, there exhibited obvious differences in drug sensitivity in terms of common drugs. A higher tumor mutation burden was shown in the high-risk group. Additionally, significant discrepancies were found between the two groups in metabolic pathways and RNA processing via GSEA analysis. Meanwhile, CIBERSORT analysis indicated different infiltrating levels of various immune cells between the two groups. Elesclomol treatment caused a unique form of programmed cell death accompanied by loss of lipoylated mitochondrial proteins and Fe-S cluster protein. The results of qRT-PCR indicated that most prognostic genes were differentially expressed in the HCC tissues.

CONCLUSION

Overall, our predictive signature displayed potential value in the prediction of overall survival of HCC patients and might provide valuable clues for personalized therapies.

Genomic and immunogenomic analysis of three prognostic signature genes in LUAD

BACKGROUND

Searching for immunotherapy-related markers is an important research content to screen for target populations suitable for immunotherapy. Prognosis-related genes in early stage lung cancer may also affect the tumor immune microenvironment, which in turn affects immunotherapy.

RESULTS

We analyzed the differential genes affecting lung cancer patients receiving immunotherapy through the Cancer Treatment Response gene signature DataBase (CTR-DB), and set a threshold to obtain a total of 176 differential genes between response and non-response to immunotherapy. Functional enrichment analysis found that these differential genes were mainly involved in immune regulation-related pathways. The early-stage lung adenocarcinoma (LUAD) prognostic model was constructed through the cancer genome atlas (TCGA) database, and three target genes (MMP12, NFE2, HOXC8) were screened to calculate the risk score of early-stage LUAD. The receiver operating characteristic (ROC) curve indicated that the model had good prognostic value, and the validation set (GSE50081, GSE11969 and GSE42127) from the gene expression omnibus (GEO) analysis indicated that the model had good stability, and the risk score was correlated with immune infiltrations to varying degrees. Multi-type survival analysis and immune infiltration analysis revealed that the transcriptome, methylation and the copy number variation (CNV) levels of the three genes were correlated with patient prognosis and some tumor microenvironment (TME) components. Drug sensitivity analysis found that the three genes may affect some anti-tumor drugs. The mRNA expression of immune checkpoint-related genes showed significant differences between the high and low group of the three genes, and there may be a mutual regulatory network between immune checkpoint-related genes and target genes. Tumor immune dysfunction and exclusion (TIDE) analysis found that three genes were associated with immunotherapy response and maybe the potential predictors to immunotherapy, consistent with the CTR-DB database analysis.

CONCLUSIONS

From the perspective of data mining, this study suggests that MMP12, NFE2, and HOXC8 may be involved in tumor immune regulation and affect immunotherapy. They are expected to become markers of immunotherapy and are worthy of further experimental research.

Triple negative breast cancer: Immunogenicity, tumor microenvironment, and immunotherapy

Triple negative breast cancer (TNBC) is a biologically diverse subtype of breast cancer characterized by genomic and transcriptional heterogeneity and exhibiting aggressive clinical behaviour and poor prognosis. In recent years, emphasis has been placed on the identification of mechanisms underlying the complex genomic and biological profile of TNBC, aiming to tailor treatment strategies. High immunogenicity, specific immune activation signatures, higher expression of immunosuppressive genes and higher levels of stromal Tumor Infiltrating Lymphocytes, constitute some of the key elements of the immune driven landscape associated with TNBC. The unprecedented response of TNBC to immunotherapy has undoubtedly changed the standard of care in this disease both in the early and the metastatic setting. However, the extent of interplay between immune infiltration and mutational signatures in TNBC is yet to be fully unravelled. In the present review, we present clinical evidence on the immunogenicity and tumour microenvironment influence on TNBC progression and the current treatment paradigms in TNBC based on immunotherapy.

The Immunosuppressive Effect of TNFR2 Expression in the Colorectal Cancer Microenvironment

Colorectal cancer (CRC) represents one of the most common causes of death among cancers worldwide. Its incidence has been increasing among the young population. Many risk factors contribute to the development and progression of CRC and about 70% of them are sporadic. The CRC microenvironment is highly heterogeneous and represents a very complex immunosuppressive platform. Many cytokines and their receptors are vital participants in this immunosuppressive microenvironment. Tumor necrosis factors (TNFs) and TNF receptor 2 (TNFR2) are critical players in the development of CRC. TNFR2 was observed to have increased the immunosuppressive activity of CRC cells via regulatory T cells (T regs) and myeloid-derived suppressor cells (MDSC) in the CRC microenvironment. However, the exact mechanism of TNFR2 in regulating the CRC prognosis remains elusive. Here, we discuss the role of TNFR2 in immune escape mechanism of CRC in the immunosuppressive cells, including Tregs and MDSCs, and the complex signaling pathways that facilitate the development of CRC. It is suggested that extensive studies on TNFR2 downstream signaling must be done, since TNFR2 has a high potential to be developed into a therapeutic agent and cancer biomarker in the future.

Exploring the landscape of immunotherapy approaches in sarcomas

Sarcomas comprise a heterogenous group of malignancies, of more than 100 different entities, arising from mesenchymal tissue, and accounting for 1% of adult malignancies. Surgery, radiotherapy and systemic therapy constitute the therapeutic armamentarium against sarcomas, with surgical excision and conventional chemotherapy, remaining the mainstay of treatment for local and advanced disease, respectively. The prognosis for patients with metastatic disease is dismal and novel therapeutic approaches are urgently required to improve survival outcomes. Immunotherapy, is a rapidly evolving field in oncology, which has been successfully applied in multiple cancers to date. Immunomodulating antibodies, adoptive cellular therapy, cancer vaccines, and cytokines have been tested in patients with different types of sarcomas through clinical trials, pilot studies, retrospective and prospective studies. The results of these studies regarding the efficacy of different types of immunotherapies in sarcomas are conflicting, and the application of immunotherapy in daily clinical practice remains limited. Additional clinical studies are ongoing in an effort to delineate the role of immunotherapy in patients with specific sarcoma subtypes.

Cost-effectiveness analysis of PD-1 inhibitors combined with chemotherapy as first-line therapy for advanced esophageal squamous-cell carcinoma in China

Objective: This study was aimed to investigate the cost-effectiveness of all available programmed death 1 (PD-1) inhibitors combined with chemotherapy in the first-line treatment of advanced esophageal squamous-cell carcinoma (ESCC) from the Chinese healthcare system perspective. Methods: A partitioned survival model with a 3-week cycle and a 10-year time horizon was constructed based on a network meta-analysis. The survival data and utility values were derived from clinical trials, and the direct medical costs were collected from public drug bidding database and published literature. Total costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were calculated. Scenario, one-way and probabilistic sensitivity analyses were performed to assess the uncertainty around model parameters. Results: Compared with mono-chemotherapy, toripalimab, sintilimab and camrelizumab plus chemotherapy were cost-effective treatment regimens, while serplulimab, pembrolizumab and nivolumab plus chemotherapy were not cost-effective options. Toripalimab plus chemotherapy provided the highest QALYs of 0.95 with the lower cost of $8,110.53 compared to other competing alternatives. The robustness of the base-case results was confirmed by scenario and one-way sensitivity analysis. At a willingness-to-pay threshold of three times per capita gross domestic product ($38,351.20) in 2021, the probability of toripalimab plus chemotherapy being the optimal option was 74.25% compared with other six competing alternatives. Conclusion: Toripalimab plus chemotherapy represented the most cost-effective option as the first-line therapy for advanced ESCC patients in China.

Review: PD-L1 as an emerging target in the treatment and prevention of keratinocytic skin cancer

Recent advances in the understanding and targeting of immune checkpoints have led to great progress in immune therapies against many forms of cancer. While many types of immune checkpoints are currently targeted in the clinic, this review will focus on recent research implicating the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) axis as an emerging focus for the treatment of keratinocytic tumors. PD-L1 is of particular interest in nonmelanoma skin cancer (NMSC), as it is not only upregulated in these tumors but is stimulated by environmental ultraviolet exposure. This response may also make PD-L1 an excellent target for photochemoprevention using topically applied small molecule inhibitors. Here, we summarize recent investigations on PD-L1 expression and clinically relevant immune checkpoint inhibitor treatment in cutaneous squamous cell carcinoma, basal cell carcinoma, and head and neck squamous cell carcinoma, as well as small molecule agents targeting PD-L1 that may be useful for clinical development aiming at treatment or prevention of NMSC.

Multi-omics analysis of N6-methyladenosine reader IGF2BP3 as a promising biomarker in pan-cancer

Background

Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) has been reported to exhibit an oncogenic effect as an RNA-binding protein (RBP) by promoting tumor cell proliferation, migration and invasion in several tumor types. However, a pan-cancer analysis of IGF2BP3 is not currently available, and the exact roles of IGF2BP3 in prognosis and immunology in cancer patients remain enigmatic. The main aim of this study was to provide visualization of the systemic prognostic landscape of IGF2BP3 in pan-cancer and to uncover the potential relationship between IGF2BP3 expression in the tumor microenvironment and immune infiltration profile.

Methods

Raw data on IGF2BP3 expression were obtained from GTEx, CCLE, TCGA, and HPA data portals. We have investigated the expression patterns, diagnostic and prognostic significance, mutation landscapes, functional analysis, and functional states of IGF2BP3 utilizing multiple databases, including HPA, TISIDB, cBioPortal, GeneMANIA, GESA, and CancerSEA. Moreover, the relationship of IGF2BP3 expression with immune infiltrates, TMB, MSI and immune-related genes was evaluated in pan-cancer. IGF2BP3 with drug sensitivity analysis was performed from the CellMiner database. Furthermore, the expression of IGF2BP3 in different grades of glioma was detected by immunohistochemical staining and western blot.

Results

We found that IGF2BP3 was ubiquitously highly expressed in pan-cancer and significantly correlated with diagnosis, prognosis, TMB, MSI, and drug sensitivity in various types of cancer. Besides, IGF2BP3 was involved in many cancer pathways and varied in different immune and molecular subtypes of cancers. Additionally, IGF2BP3 is critically associated with genetic markers of immunomodulators in various cancers. Finally, we validated that IGF2BP3 protein expression was significantly higher in glioma than in normal tissue, especially in GBM.

Conclusions

IGF2BP3 may be a potential molecular biomarker for diagnosis and prognosis in pan-cancer, especially for glioma. It could become a novel therapeutic target for various cancers.

The efficacy and safety of anti-PD-1/PD-L1 in treatment of glioma: a single-arm meta-analysis

Objective

This meta-analysis aimed to evaluate the efficacy and safety of PD-1/PD-L1 inhibitors in patients with glioma.

Methods

PubMed, EMBASE, Web of Science, and the Cochrane library were searched from inception to January 2023 without language restriction. Primary outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs). The risk of bias was assessed by subgroup analysis, sensitivity analysis, and publication bias, including funnel plot, Egger's test, and Begg's test.

Results

A total of 20 studies involving 2,321 patients were included in this meta-analysis. In the analysis of the included phase III clinical trials, the forest plot showed that PD-1/PD-L1 inhibitors did not improve the OS (HR=1.15, 95% CI: 1.03-1.29, P=0.02, I² = 14%) and PFS (HR=1.43, 95% CI: 1.03-1.99, P=0.03, I² = 87%). In the single-arm analysis, the forest plot demonstrated that the 6-month OS was 71% (95% CI: 57%-83%, I² = 92%), 1-year OS was 43% (95% CI: 33%-54%, I² = 93%), and the 2-year OS was 27% (95% CI: 13%-44%, I² = 97%). The pooled estimate of the median OS was 8.85 months (95% CI: 7.33-10.36, I² = 91%). Furthermore, the result indicated that the 6-month PFS was 28% (95% CI: 18%-40%, I² = 95%), 1-year PFS was 15% (95% CI: 8%-23%, I² = 92%), and the 18-month PFS was 10% (95% CI: 3%-20%, I² = 93%). The pooled estimate of the median PFS was 3.72 months (95% CI: 2.44-5.00, I² = 99%). For ORR, the pooled estimate of ORR was 10% (95% CI: 2%-20%, I² = 88%). We further analyzed the incidence of PD-1/PD-L1 inhibitor-related AEs, and the pooled incidence of AEs was 70% (95% CI: 58%-81%, I² = 94%). The incidence of AEs ≥ grade 3 was 19% (95% CI: 11%-30%, I² = 94%). The funnel plot for the median PFS and median OS was symmetric with no significant differences in Egger's test and Begg's test. The sensitivity analysis revealed that our results were stable and reliable.

Conclusion

The results of this meta-analysis suggest that anti-PD-1/PD-L1 therapy is relatively safe but could not prolong survival in glioma. More randomized controlled trials are needed to confirm our results.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023396057.