A snapshot of the PD-1/PD-L1 pathway

Obesity Promotes Marrow-Derived Myeloid Cell Accumulation While Exercise Reduces Proliferative Signaling in Colon Cancer

PURPOSE

Obesity increases colon cancer risk that has been previously linked to marrow-derived myeloid cells. We previously demonstrated that exercise training (EX) prevents colon cancer initiation, potentially through reduced myelopoiesis. However, it remains unknown whether early myeloid cell accumulation and inflammation in the colon precedes carcinogenesis with high-fat diet (HFD)-induced obesity, and if EX can attenuate these effects. We hypothesized that obesity would promote colon carcinogenesis that was preceded by myeloid cell accumulation and inflammation that would be attenuated by EX.

METHODS

C57BL/6 mice were randomized to a HFD or control (CON) diet for 8 weeks. The HFD mice switched to CON diet and all mice were given intraperitoneal injections of azoxymethane (AOM) to induce colon cancer and randomized into EX or sedentary (SED) conditions.

RESULTS

HFD mice developed more aberrant crypt foci (ACF), a marker for early carcinogenesis, compared with CON ( P < 0.01), and EX developed fewer ACF compared with SED ( P < 0.0001). Marrow-derived ( P < 0.001) CD206 + macrophages were elevated in HFD compared with CON at study week 16 ( P < 0.01). Marrow-derived CD206 - macrophages ( P < 0.05) and marrow-derived ( P < 0.05) CD206 + macrophages were more abundant in HFD compared with CON at study week 42. EX did not alter colon immune cell populations. β-catenin protein was higher in HFD compared with CON at study week 42 ( P < 0.05), and STAT3 protein content was lower at study week 28 with EX compared with SED ( P < 0.05).

CONCLUSIONS

The results suggest that obesity promotes colon ACF formation, potentially through early inflammatory myeloid cell accumulation. Despite attenuating ACF, EX did not alter myeloid cell accumulation in the colon, suggesting that EX inhibits ACF formation through alternative mechanisms which may include reduced β-catenin and STAT3 signaling.

Pulsed electric field ablation as a candidate to enhance the anti-tumor immune response to immune checkpoint inhibitors

Cancer ablation with pulsed electric fields (PEFs) involves the delivery of high-voltage, short-duration electrical pulses that destabilize tumor cells, leading to cellular death. Unlike most conventional ablation technologies, PEF ablation is non-thermal, allowing for safe and targeted energy delivery to the tumor without damaging surrounding tissue and critical structures. PEFs allow for specific dosing, predictable treatment zones, and preservation of the extracellular matrix and adjacent vascular tissues. Preclinical and preliminary clinical data suggest that PEF ablation may induce inflammatory changes in the tumor microenvironment (TME) that engage host innate and adaptive immune cells, stimulating an anti-tumor response. Specifically, PEF promotes local and systemic anti-tumor immune activation through immunogenic cell death and the release of damage-associated molecular patterns (DAMPs) and tumor antigens. This tumor-specific immune activation could potentially enhance response to immune checkpoint inhibitor (ICI) therapies. Furthermore, PEF ablation induces the formation of tertiary lymphoid structures (TLSs) in the TME, which are predictive biomarkers for responsiveness to ICI across several solid tumors. This combination of effects activates antigen-presenting cells and stimulates the effector T cell response, which is often inhibited in ICI-resistant cancer patients. In this review, the onco-immunological characteristics of PEF ablation are discussed, with special emphasis placed on the clinical potential of PEF ablation to induce anti-cancer immune responses and enhance responsiveness to ICI therapy in ablated and non-ablated (abscopal) tumors.

Reduced expression of programmed cell death protein 1 on peripheral regulatory B cells in pre-eclampsia - Signs of impaired immune suppression

Immunological changes are believed to be a part of pre-eclampsia etiology. This study investigated the distribution of the specific peripheral B lymphocyte phenotypes in pre-eclampsia cases compared to uncomplicated pregnancies. The study cohort included 29 women with pre-eclampsia and 14 women with uncomplicated pregnancies. Blood samples were collected in the third trimester of primigravidae pregnancies, and immune cells were analyzed using flow cytometry. Cases with pre-eclampsia showed a significantly reduced expression of programmed cell death protein 1 (PD-1) on CD27+CD24hiCD38hi regulatory B cells compared with control pregnancies (p = 0.002; multivariate logistic regression: p = 0.009). Trends for a reduced PD-1 expression on regulatory CD27+CD24hi B cells and on live CD19+ B cells were observed in cases of pre-eclampsia (p = 0.011 and p = 0.035; respectively). No significant differences between pre-eclampsia cases and controls in percentages of B cells, B1a cells, plasmablasts, naïve B cells, transitional/immature B cells, memory B cells, regulatory CD27+CD24hi B cells and regulatory CD27+CD24hiCD38hi B cells were observed. This is the first study to report reduced PD-1 expression on live B cells and regulatory B cells in pre-eclampsia. These results are in line with previous studies of peripheral regulatory T cells and decidual lymphocytes from pre-eclampsia patients. Reduced PD-1 expression on regulatory B cells in pre-eclampsia could indicate that a lack of immune suppression might play a role in the pathophysiology of pre-eclampsia.

Copper in the colorectal cancer microenvironment: pioneering a new era of cuproptosis-based therapy

Copper, an essential trace element and biochemical cofactor in humans plays a critical role in maintaining health. Recent studies have identified a significant association between copper levels and the progression and metastasis of cancer. Copper is primarily absorbed in the intestinal tract, often leading to an imbalance of copper ions in the body. Colorectal cancer (CRC), the most common cancer originating in the intestines, thrives in an environment with elevated copper concentrations. Current research is focused on uncovering the relationship between copper and CRC which has introduced new concepts such as cuproplasia and cuproptosis, significantly deepening our understanding of copper's influence on cell proliferation and death. Cuproplasia is a kind of cell proliferation mediated by the co-regulatory activities of enzymes and non-enzymatic factors, while cuproptosis refers to cell death induced by excessive copper, which results in abnormal oligomerization of lipacylated proteins and the reduction of iron-sulfur cluster proteins. Exploring cuproplasia and cuproptosis opens new avenues for treating CRC. This review aims to summarize the critical role of copper in promoting colorectal cancer, the dual effects of copper in the tumor microenvironment (TME), and strategies for leveraging this unique microenvironment to induce cuproptosis in colorectal cancer. Understanding the relationship between copper and CRC holds promise for establishing a theoretical foundation for innovative therapeutic strategies in CRC.

The role of inhibitory immune checkpoint receptors in the pathogenesis of Alzheimer's disease

There is mounting evidence that microglial cells have a key role in the pathogenesis of Alzheimer's disease (AD). In AD pathology, microglial cells not only are unable to remove β-amyloid (Aβ) plaques and invading pathogens but also are involved in synaptic pruning, chronic neuroinflammation, and neuronal degeneration. Microglial cells possess many different inhibitory immune checkpoint receptors, such as PD-1, LILRB2-4, Siglecs, and SIRPα receptors, which can be targeted by diverse cell membrane-bound and soluble ligand proteins to suppress the functions of microglia. Interestingly, in the brains of AD patients there are elevated levels of many of the inhibitory ligands acting via these inhibitory checkpoint receptors. For instance, Aβ oligomers, ApoE4, and fibronectin are able to stimulate the LILRB2-4 receptors. Increased deposition of sialoglycans, e.g., gangliosides, inhibits microglial function via Siglec receptors. AD pathology augments the accumulation of senescent cells, which are known to possess a high level of PD-L1 proteins, and thus, they can evade immune surveillance. A decrease in the expression of SIRPα receptor in microglia and its ligand CD47 in neurons enhances the phagocytic pruning of synapses in AD brains. Moreover, cerebral neurons contain inhibitory checkpoint receptors which can inhibit axonal growth, reduce synaptic plasticity, and impair learning and memory. It seems that inappropriate inhibitory immune checkpoint signaling impairs the functions of microglia and neurons thus promoting AD pathogenesis. KEY MESSAGES: Microglial cells have a major role in the pathogenesis of AD. A decline in immune activity of microglia promotes AD pathology. Microglial cells and neurons contain diverse inhibitory immune checkpoint receptors. The level of ligands for inhibitory checkpoint receptors is increased in AD pathology. Impaired signaling of inhibitory immune checkpoint receptors promotes AD pathology.

Immune Checkpoint Inhibitor-Associated Cutaneous Adverse Events: Mechanisms of Occurrence

Immunotherapy, particularly that based on blocking checkpoint proteins in many tumors, including melanoma, Merkel cell carcinoma, non-small cell lung cancer (NSCLC), triple-negative breast (TNB cancer), renal cancer, and gastrointestinal and endometrial neoplasms, is a therapeutic alternative to chemotherapy. Immune checkpoint inhibitor (ICI)-based therapies have the potential to target different pathways leading to the destruction of cancer cells. Although ICIs are an effective treatment strategy for patients with highly immune-infiltrated cancers, the development of different adverse effects including cutaneous adverse effects during and after the treatment with ICIs is common. ICI-associated cutaneous adverse effects include mostly inflammatory and bullous dermatoses, as well as severe cutaneous side reactions such as rash or inflammatory dermatitis encompassing erythema multiforme; lichenoid, eczematous, psoriasiform, and morbilliform lesions; and palmoplantar erythrodysesthesia. The development of immunotherapy-related adverse effects is a consequence of ICIs' unique molecular action that is mainly mediated by the activation of cytotoxic CD4+/CD8+ T cells. ICI-associated cutaneous disorders are the most prevalent effects induced in response to anti-programmed cell death 1 (PD-1), anti-cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), and anti-programmed cell death ligand 1 (PD-L1) agents. Herein, we will elucidate the mechanisms regulating the occurrence of cutaneous adverse effects following treatment with ICIs.

Solid cancer-directed CAR T cell therapy that attacks both tumor and immunosuppressive cells via targeting PD-L1

Chimeric antigen receptor (CAR) T cell therapy has encountered limited success in solid tumors. The lack of dependable antigens and the immunosuppressive tumor microenvironment (TME) are major challenges. Within the TME, tumor cells along with immunosuppressive cells employ an immune-evasion mechanism that upregulates programmed death ligand 1 (PD-L1) to deactivate effector T cells; this makes PD-L1 a reliable, universal target for solid tumors. We developed a novel PD-L1 CAR (MC9999) using our humanized anti-PD-L1 monoclonal antibody, designed to simultaneously target tumor and immunosuppressive cells. The antigen-specific antitumor effects of MC9999 CAR T cells were observed consistently across four solid tumor models: breast cancer, lung cancer, melanoma, and glioblastoma multiforme (GBM). Notably, intravenous administration of MC9999 CAR T cells eradicated intracranially established LN229 GBM tumors, suggesting penetration of the blood-brain barrier. The proof-of-concept data demonstrate the cytolytic effect of MC9999 CAR T cells against immunosuppressive cells, including microglia HMC3 cells and M2 macrophages. Furthermore, MC9999 CAR T cells elicited cytotoxicity against primary tumor-associated macrophages within GBM tumors. The concept of targeting both tumor and immunosuppressive cells with MC9999 was further validated using CAR T cells derived from cancer patients. These findings establish MC9999 as a foundation for the development of effective CAR T cell therapies against solid tumors.

Role of PD-1/PD-L1 signaling axis in oncogenesis and its targeting by bioactive natural compounds for cancer immunotherapy

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

Prevalence of HPV in anal cancer: exploring the role of infection and inflammation

Anal cancer incidence is rising globally, driven primarily by human papillomavirus (HPV) infection. HPV, especially high-risk types 16 and 18, is considered a necessary cause of anal squamous cell carcinoma. Certain populations like people living with HIV, men who have sex with men, inflammatory bowel disease patients, smokers, and those with compromised immunity face elevated risk. Chronic inflammation facilitates viral persistence, cell transformation, and immune evasion through pathways involving the PD-1/PD-L1 axis. HIV coinfection further increases risk by impairing immune surveillance and epithelial integrity while promoting HPV oncogene expression. Understanding these inflammatory processes, including roles of CD8 + T cells and PD-1/PD-L1, could guide development of immunotherapies against anal cancer. This review summarizes current knowledge on inflammation's role in anal cancer pathogenesis and the interplay between HPV, HIV, and host immune factors.

Notch Signaling and PD-1/PD-L1 Interaction in Hepatocellular Carcinoma: Potentialities of Combined Therapies

Immunotherapy has shown significant improvement in the survival of patients with hepatocellular carcinoma (HCC) compared to TKIs as first-line treatment. Unfortunately, approximately 30% of HCC exhibits intrinsic resistance to ICIs, making new therapeutic combinations urgently needed. The dysregulation of the Notch signaling pathway observed in HCC can affect immune cell response, reducing the efficacy of cancer immunotherapy. Here, we provide an overview of how Notch signaling regulates immune responses and present the therapeutic rationale for combining Notch signaling inhibition with ICIs to improve HCC treatment. Moreover, we propose using exosomes as non-invasive tools to assess Notch signaling activation in hepatic cancer cells, enabling accurate stratification of patients who can benefit from combined strategies.

Evolving Treatment Landscape of Frontline Therapy for Metastatic Urothelial Carcinoma: Current Insights and Future Perspectives

Cisplatin-based chemotherapy has long been the standard first-line (1L) treatment for metastatic urothelial carcinoma (mUC). However, up to 50% of patients with mUC may be ineligible for cisplatin owing to comorbidities, necessitating alternative primary treatment options. Immune checkpoint inhibitors (ICIs) have emerged as a vital alternative for those unable to receive cisplatin. Nevertheless, the prognosis of advanced UC remains dire and challenges persist in optimizing 1L therapy. Recent medical advancements have redirected attention towards innovative drug combinations for the primary treatment of mUC. The combination of enfortumab vedotin (EV) and pembrolizumab has shown significantly improved overall and progression-free survival rates compared to those with chemotherapy alone. This combination can be used as a 1L treatment for patients with mUC who are cisplatin-ineligible or require alternatives to standard chemotherapy. While platinum-based chemotherapy continues to be essential for many patients, the approval of EV and pembrolizumab as 1L treatments for cisplatin-ineligible patients signifies a major breakthrough in primary cancer care. These therapies offer enhanced outcomes in terms of survival and response rates and highlight the increasing relevance of ICI-containing regimens in frontline cancer care. This review provides an exhaustive overview of the current frontline treatment landscape of mUC and explores new therapeutic strategies, with the aim of facilitating clinical decision-making and guiding therapeutic strategies in patients with mUC.

Knockout of B2M in combination with PD-L1 overexpression protects MSC-derived new islet β cells from graft rejection in the treatment of canine diabetes mellitus

BACKGROUND

The immunogenicity of allogeneic mesenchymal stem cells (MSCs) is significantly enhanced after transplantation or differentiation, and these cells can be recognized and cleared by recipient immune cells. Graft rejection has become a major obstacle to improving the therapeutic effect of allogeneic MSCs or, after their differentiation, transplantation in the treatment of diabetes and other diseases. Solving this problem is helpful for prolonging the time that cells play a role in the recipient body and for significantly improving the clinical therapeutic effect.

METHODS

In this study, canine adipose-derived mesenchymal stem cells (ADSCs) were used as seed cells, and gene editing technology was used to knock out the B2M gene in these cells and cooperate with the overexpression of the PD-L1 gene. Gene-edited ADSCs (GeADSCs), whose biological characteristics and safety are not different from those of normal canine ADSCs, have been obtained.

RESULTS

The immunogenicity of GeADSCs is reduced, the immune escape ability of GeADSCs is enhanced, and GeADSCs can remain in the body for a longer time. Using the optimized induction program, the efficiency of the differentiation of GeADSCs into new islet β-cells was increased, and the maturity of the new islet β-cells was increased. The immunogenicity of new islet β-cells decreased, and their immune escape ability was enhanced after the cells were transplanted into diabetic dogs (the graft site was prevascularized by the implantation of a scaffold to form a vascularized pouch). The number of infiltrating immune cells and the content of immune factors were decreased at the graft site.

CONCLUSIONS

New islet β-cell transplantation, which has low immunogenicity, can reverse diabetes in dogs, and the therapeutic effect of cell transplantation is significantly enhanced. This study provides a new method for prolonging the survival and functional time of cells in transplant recipients and significantly improving the clinical therapeutic effect.

Immune Checkpoints in B Cells: Unlocking New Potentials in Cancer Treatment

B cells are crucial component of humoral immunity, and their role in the tumor immune microenvironment (TME) has garnered significant attention in recent years. These cells hold great potential and application prospects in the field of tumor immunotherapy. Research has demonstrated that the TME can remodel various B cell functions, including proliferation, differentiation, antigen presentation, and antibody production, thereby invalidating the anti-tumor effects of B cells. Concurrently, numerous immune checkpoints (ICs) on the surface of B cells are upregulated. Aberrant B-cell IC signals not only impair the function of B cells themselves, but also modulate the tumor-killing effects of other immune cells, ultimately fostering an immunosuppressive TME and facilitating tumor immune escape. Blocking ICs on B cells is beneficial for reversing the immunosuppressive TME and restoring anti-tumor immune responses. In this paper, the intricate connection between B-cell ICs and the TME is delved into, emphasizing the critical role of targeting B-cell ICs in anti-tumor immunity, which may provide valuable insights for the future development of tumor immunotherapy based on B cells.

Integrated proteomic and glycoproteomic analysis reveals heterogeneity and molecular signatures of brain metastases from lung adenocarcinomas

Brain metastasis is a major cause of poor prognosis and death in lung adenocarcinoma (LUAD); however, the understanding of therapeutic strategies and mechanisms for brain metastases from LUAD (BM-LUAD) remains notably limited, especially at the proteomics levels. To address this issue, we conducted integrated proteomic and glycoproteomic analyses on 49 BM-LUAD tumors, revealing two distinct subtypes of the disease: BM-S1 and BM-S2. Whole exome sequencing analysis revealed that somatic mutations in STK11 and KEAP1, as well as copy number deletions on chr19p13.3, such as STK11, UQCR11, and SLC25A23, were more frequently detected in BM-S2. In BM-S1 tumors, we observed significant infiltration of GFAP + astrocytes, as evidenced by elevated levels of GFAP, GABRA2, GABRG1 and GAP43 proteins and an enrichment of astrocytic signatures in both our proteomic data and external spatial transcriptomic data. Conversely, BM-S2 tumors demonstrated higher levels of PD-1 immune cell infiltration, supported by the upregulation of PD-1 and LAG-3 genes. These findings suggest distinct microenvironmental adaptations required by the different BM-LUAD subtypes. Additionally, we observed unique glycosylation patterns between the subtypes, with increased fucosylation in BM-S1 and enhanced sialylation in BM-S2, primarily affected by glycosylation enzymes such as FUT9, B4GALT1, and ST6GAL1. Specifically, in BM-S2, these sialylation modifications are predominantly localized to the lysosomes, underscoring the critical role of N-glycosylation in the tumor progression of BM-LUAD. Overall, our study not only provides a comprehensive multi-omic data resource but also offers valuable biological insights into BM-LUAD, highlighting potential mechanisms and therapeutic targets for further investigation.

The Role of PD-1/PD-L1 and IL-7 in Lymphocyte Dynamics and Sepsis Progression: A Biomarker Study in Critically Ill Patients

Sepsis pathophysiology involves a dysregulated immune response to infection, excessive inflammation, and immune paralysis. This study explores the relationships between cell death biomarkers (serum-soluble levels of programmed cell death protein 1 (PD-1), programmed death ligand 1 (PD-L1), and interleukin-7 (IL-7)) and the percentages of various lymphocyte subsets in relation to the severity and progression of sepsis. This prospective, observational study included 87 critically ill patients. We monitored parameters on days 1 (sepsis was diagnosed according to the Sepsis-3 Consensus) and 5. We established an IL-7 cutoff value of 1.94 pg/mL by comparing levels between a healthy control group and patients with sepsis (p < 0.0001). Lymphopenia was observed in all patients, with negative correlations between helper T lymphocytes and cytotoxic and B lymphocytes, and positive correlations involving cytotoxic lymphocytes across all groups. We found correlations between PD-1/PD-L1 and lymphocyte subsets. IL-7 showed a statistical correlation with PD-1 in non-survivors. Assessing lymphocyte levels shows potential as a biomarker for evaluating the progression of sepsis. Monitoring IL-7 levels could help assess survival, as low levels are associated with higher mortality risk. Monitoring IL-7 levels could help assess survival, as low levels are associated with higher mortality risk. Elevated PD-1/PD-L1 expression impairs costimulatory signalling, reducing T cell responses and lymphopenia, which increases the risk of nosocomial infections.

IMM2520, a novel anti-CD47/PD-L1 bispecific antibody for cancer immune therapy

PD-1/PD-L1 is an important signaling pathway in the adaptive immune system. The CD47/SIRPα signaling pathway is a crucial "do not eat me" signal for innate immunity. This study evaluated the anti-tumor mechanism of IMM2520 in vitro and in vivo. IMM2520 was generated using the "mab-trap" platform. IMM2520 showed high affinity to PD-L1 and relatively lower affinity to CD47, displaying preferential binding to PD-L1 on tumor cells. IMM2520 had the potent ability to inhibit the PD-1/PD-L1 and CD47/SIRPα signaling pathways and killed tumor cells through ADCC and ADCP. Importantly, IMM2520 did not bind to human red blood cells or induce erythrocyte agglutination. IMM2520 demonstrated a tendency to bind to CD47+/PD-L1+ tumor cells, reducing its binding to CD47 single-positive cells. In mouse transplantation models, compared with the first-generation CD47/PD-L1 BsAb (IMM2505), IMM2520 exhibited stronger and dose-dependent antitumor activity. These findings imply that IMM2520 may offer a novel therapeutic alternative for cancer patients.

Synergistic integration of mRNA-LNP with CAR-engineered immune cells: Pioneering progress in immunotherapy

Chimeric antigen receptor T cell (CAR-T) therapy has emerged as a revolutionary approach in the treatment of malignancies. Despite its remarkable successes, this field continues to grapple with challenges such as scalability, safety concerns, limited therapeutic effect, in vivo persistence, and the need for precise control over CAR expression. In the post-pandemic era of COVID-19 vaccine immunization, the application of messenger RNA (mRNA) encapsulated within lipid nanoparticles (LNPs) has recently garnered significant attention as a potential solution to address these challenges. This review delves into the dynamic landscape of mRNA-LNP technology and its potential implications for CAR-engineered immune cell-based immunotherapy.

Anti-CTLA-4 antibody self-presented dendritic cell nanovesicles boost the immunotherapy of hepatocellular carcinoma after microwave ablation

Microwave ablation (MWA) is a frequently adopted regional therapy for treating hepatocellular carcinoma (HCC) in clinic. However, incomplete microwave ablation (IMWA) is often inevitable due to the restraint of ablating large tumors or tumors in special locations, resulting in a high recurrence rate of HCC. Moreover, the most promising immune checkpoint blockade (ICB)-based immunotherapy is raising hindered by the toxicity and insufficient immune response. To overcome these barriers, we conjugate small nanovesicle (smDV)-derived from matured dendritic cells (mDCs) with anti-CTLA-4 antibody (smDV-aCTLA-4) using a metabolic tagging technology, which could trigger the infiltration of cytotoxic T cells (CTLs) and adopted tumor-infiltrating lymphocytes (TILs) in residual HCC after IMWA. In HCC microenvironment, the administration of smDV-aCTLA-4 could promote antigen presentation and immune checkpoint suppression to activate CTLs and improve the safety of anti-CTLA-4 antibody. Moreover, the anti-tumor efficacy of CTLs elicited by smDV-aCTLA-4 could also be further enhanced by anti-programmed death 1 (aPD-1) antibody. In addition, compared to the adoptive TILs therapy, the treatment using smDV-aCTLA-4-bonded TILs (smDV-aCTLA-4@TILs) could promote the proliferation and infiltration of cytotoxic TILs in residual HCC after IMWA. Our results clearly evidenced the potency of a new type of engineered DC nanovesicles in reducing HCC recurrence after IMWA.

Expression of Programmed Death Ligand 1 and Indoleamine 2,3-Dioxygenase in Oral Lichen Planus and Oral Lichenoid Lesions

BACKGROUND

Oral lichen planus (OLP) and oral lichenoid lesions (OLL) are inflammatory T-cell mediated disorders of the oral mucosa (OM). Both are associated with an increased risk of oral squamous cell carcinoma, with OLL possibly having a higher rate of malignant transformation than OLP. Programmed death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase (IDO) are immunosuppressive molecules possessing inhibitory effect on T-cells and have been implicated in carcinogenesis. The aim of this study was to examine the expression of PD-L1 and IDO in OLP and OLL.

METHODS

Sixty-eight formalin-fixed, paraffin-embedded tissue samples diagnosed as OLP, compatible with OLP, or OLL were divided into OLP (n = 39) or OLL (n = 29) groups based on both clinical and histopathological diagnostic criteria. Samples of healthy OM (n = 9) served as controls. Samples were immunohistochemically stained for PD-L1 and IDO, and staining distribution and intensity were evaluated.

RESULTS

Immunohistochemical expression of PD-L1 was increased in the basal and intermediate layers of epithelium in OLP and in lamina propria in both OLP and OLL compared to controls. OLP and OLL showed increased expression of IDO in epithelium and lamina propria compared to controls. PD-L1 staining intensity in the basal epithelial layer, and IDO staining intensity in lamina propria were increased in OLP compared to OLL.

CONCLUSION

The results indicate that the expression of PD-L1 and IDO increases in OLP and OLL, suggesting that these molecules may play a role in the pathogenesis of both disorders.

Hypoxia-induced PD-L1 expression and modulation of muscle stem cell allograft rejection

Stem cell therapy has shown immense promise in treating genetic disorders, particularly muscular diseases like Duchenne muscular dystrophy (DMD). This study investigates a novel method to enhance the viability of stem cell transplants in DMD by upregulating Programmed Death Ligand 1 (PD-L1) in muscle stem cells (MuSCs) through preconditioning with hypoxia and/or interferon-γ (IFN-γ) to mitigate T cell immune rejection. MuSCs were treated with 5% hypoxia for 72 h and further treated with IFN-γ to enhance PD-L1 expression. Additionally, gain and loss experiments using a PD-L1 inhibitor (BMS-1) were conducted to investigate cellular expression profiles in vitro and cell transplantation outcomes in vivo. Our results showed significant upregulation of PD-L1 in MuSCs under hypoxia and IFN-γ conditions without affecting cellular proliferation and differentiation in vitro. In vivo, these preconditioned MuSCs led to decreased infiltration of CD4+ and CD8+ T cells in implanted limb muscles of mouse models. Blocking PD-L1 reduced graft survival in muscles treated with MuSCs. Conversely, increased PD-L1 expression and reduced T cell infiltration correlated with improved graft survival, as identified by pre-labeled LacZ + MuSCs following transplantation. This study provides evidence that hypoxia and IFN-γ preconditioning of MuSCs can significantly enhance the efficacy of cell therapy for DMD by mitigating immune rejection. Our strategic approach aimed to improve donor cell survival and function post-transplantation by modifying immune responses towards the donor cells.

PD-1 immunology in the kidneys: a growing relationship

In recent years, knowledge regarding immune regulation has expanded rapidly, and major advancements have been made in immunotherapy for immune-associated disorders, particularly cancer. The programmed cell death 1 (PD-1) pathway is a cornerstone in immune regulation. It comprises PD-1 and its ligands mediating immune tolerance mechanisms and immune homeostasis. Accumulating evidence demonstrates that the PD-1 axis has a crucial immunosuppressive role in the tumor microenvironment and autoimmune diseases. PD-1 receptors and ligands on immune cells and renal parenchymal cells aid in maintaining immunological homeostasis in the kidneys. Here, we present a comprehensive review of PD-1 immunology in various kidney disorders, including renal cell carcinoma, glomerulonephritis, kidney transplantation, renal aging, and renal immune-related adverse events secondary to PD-1 immunotherapy.

Detection and Validation of Organic Metabolites in Urine for Clear Cell Renal Cell Carcinoma Diagnosis

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) comprises the majority, approximately 70-80%, of renal cancer cases and often remains asymptomatic until incidentally detected during unrelated abdominal imaging or at advanced stages. Currently, standardized screening tests for renal cancer are lacking, which presents challenges in disease management and improving patient outcomes. This study aimed to identify ccRCC-specific volatile organic compounds (VOCs) in the urine of ccRCC-positive patients and develop a urinary VOC-based diagnostic model.

METHODS

This study involved 233 pretreatment ccRCC patients and 43 healthy individuals. VOC analysis utilized stir-bar sorptive extraction coupled with thermal desorption gas chromatography/mass spectrometry (SBSE-TD-GC/MS). A ccRCC diagnostic model was established via logistic regression, trained on 163 ccRCC cases versus 31 controls, and validated with 70 ccRCC cases versus 12 controls, resulting in a ccRCC diagnostic model involving 24 VOC markers.

RESULTS

The findings demonstrated promising diagnostic efficacy, with an Area Under the Curve (AUC) of 0.94, 86% sensitivity, and 92% specificity.

CONCLUSIONS

This study highlights the feasibility of using urine as a reliable biospecimen for identifying VOC biomarkers in ccRCC. While further validation in larger cohorts is necessary, this study's capability to differentiate between ccRCC and control groups, despite sample size limitations, holds significant promise.

Inhibitory immune checkpoints suppress the surveillance of senescent cells promoting their accumulation with aging and in age-related diseases

The accumulation of pro-inflammatory senescent cells within tissues is a common hallmark of the aging process and many age-related diseases. This modification has been called the senescence-associated secretory phenotype (SASP) and observed in cultured cells and in cells isolated from aged tissues. Currently, there is a debate whether the accumulation of senescent cells within tissues should be attributed to increased generation of senescent cells or to a defect in their elimination from aging tissues. Emerging studies have revealed that senescent cells display an increased expression of several inhibitory immune checkpoint ligands, especially those of the programmed cell death protein-1 (PD-1) ligand-1 (PD-L1) proteins. It is known that the PD-L1 ligands, especially those of cancer cells, target the PD-1 receptor of cytotoxic CD8+ T and natural killer (NK) cells disturbing their functions, e.g., evoking a decline in their cytotoxic activity and promoting their exhaustion and even apoptosis. An increase in the level of the PD-L1 protein in senescent cells was able to suppress their immune surveillance and inhibit their elimination by cytotoxic CD8+ T and NK cells. Senescent cells are known to express ligands for several inhibitory immune checkpoint receptors, i.e., PD-1, LILRB4, NKG2A, TIM-3, and SIRPα receptors. Here, I will briefly describe those pathways and examine whether these inhibitory checkpoints could be involved in the immune evasion of senescent cells with aging and age-related diseases. It seems plausible that an enhanced inhibitory checkpoint signaling can prevent the elimination of senescent cells from tissues and thus promote the aging process.

Anti-PD-L1 checkpoint inhibitor combined with nanocarrier-mediated cisplatin codelivery system for effective treatment of pancreatic cancer

Immune checkpoint inhibitor-based cancer immunotherapy has shown promise as a potential treatment in the clinic. It has been reported that anti-PD-L1 combined with cisplatin treatment can improve the antitumor effect. However, the therapeutic outcome is limited due to the abundance of tumor stroma in pancreatic cancer (PC), which prevented the penetration of cisplatin and anti-PD-L1 into tumor regions, thus impeding the effectiveness in the treatment of PC. In this study, a nanocarrier-mediated codelivery system of hyaluronidase and cisplatin was constructed, which can degrade the stroma and promote cisplatin and anti-PD-L1 to penetrate the tumor stroma into the deep tumor, so as to suppress PC effectively. When combined the cisplatin nanocarrier system BPEI-SS-Pt/HAase@CaP (BSP/H@CaP) with an immune checkpoint inhibitor to overcome the poor therapeutic outcome of PC, the results indicated that the therapeutic effect of BSP/H@CaP combined with anti-PD-L1 was better than that of BSP/H@CaP and single anti-PD-L1 group. Because the stroma is degrading, a higher amount of BPEI-SS-Pt and anti-PD-L1 can enter the tumor stroma and reach the inner depths of the tumor for immune stimulation, leading to a synergistically augmented chemotherapy and immunotherapy for PC. The above combination therapy is useful for clinical translation to overcome the treatment resistance of matrix-rich PC.

The role of programmed death receptor (PD-)1/PD-ligand (L)1 in periodontitis and cancer

The programmed-death-ligand-1 (PD-L1) is an immune-modulating molecule that is constitutively expressed on various immune cells, different epithelial cells and a multitude of cancer cells. It is a costimulatory molecule that may impair T-cell mediated immune response. Ligation to the programmed-death-receptor (PD)-1, on activated T-cells and further triggering of the related signaling pathways can induce T-cells apoptosis or anergy. The upregulation of PD-L1 in various cancer types, including oral squamous cell carcinomas, was demonstrated and has been linked to immune escape of tumors and poor prognosis. A bidirectional relationship exists between the increased PD-L1 expression and periodontitis as well as the epithelial-mesenchymal transition (EMT), a process of interconversion of epithelial cells to mesenchymal cells that may induce immune escape of tumors. Interaction between exosomal PD-L1 and PD-1 on T-cells may cause immunosuppression by blocking the activation and proliferation of T-cells. The efficacy and importance of treatment with PD-1/PD-L1 checkpoint inhibitors and their prognostic influence on human cancers was demonstrated. Regarding PD-1/PD-L1 checkpoint inhibitors, resistances exist or may develop, basing on various factors. Further investigations of the underlying mechanisms will help to overcome the therapeutic limitations that result from resistances and to develop new strategies for the treatment of cancer.

Alternative Strategies for Delivering Immunotherapeutics Targeting the PD-1/PD-L1 Immune Checkpoint in Cancer

The programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immune checkpoint constitutes an inhibitory pathway best known for its regulation of cluster of differentiation 8 (CD8)+ T cell-mediated immune responses. Engagement of PD-L1 with PD-1 expressed on CD8+ T cells activates downstream signaling pathways that culminate in T cell exhaustion and/or apoptosis. Physiologically, these immunosuppressive effects exist to prevent autoimmunity, but cancer cells exploit this pathway by overexpressing PD-L1 to facilitate immune escape. Intravenously (IV) administered immune checkpoint inhibitors (ICIs) that block the interaction between PD-1/PD-L1 have achieved great success in reversing T cell exhaustion and promoting tumor regression in various malignancies. However, these ICIs can cause immune-related adverse events (irAEs) due to off-tumor toxicities which limits their therapeutic potential. Therefore, considerable effort has been channeled into exploring alternative delivery strategies that enhance tumor-directed delivery of PD-1/PD-L1 ICIs and reduce irAEs. Here, we briefly describe PD-1/PD-L1-targeted cancer immunotherapy and associated irAEs. We then provide a detailed review of alternative delivery approaches, including locoregional (LDD)-, oncolytic virus (OV)-, nanoparticle (NP)-, and ultrasound and microbubble (USMB)-mediated delivery that are currently under investigation for enhancing tumor-specific delivery to minimize toxic off-tumor effects. We conclude with a commentary on key challenges associated with these delivery methods and potential strategies to mitigate them.

Photonanozyme-Kras-ribosome combination treatment of non-small cell lung cancer after COVID-19

With the outbreak of the coronavirus disease 2019 (COVID-19), reductions in T-cell function and exhaustion have been observed in patients post-infection of COVID-19. T cells are key mediators of anti-infection and antitumor, and their exhaustion increases the risk of compromised immune function and elevated susceptibility to cancer. Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer with high incidence and mortality. Although the survival rate after standard treatment such as surgical treatment and chemotherapy has improved, the therapeutic effect is still limited due to drug resistance, side effects, and recurrence. Recent advances in molecular biology and immunology enable the development of highly targeted therapy and immunotherapy for cancer, which has driven cancer therapies into individualized treatments and gradually entered clinicians' views for treating NSCLC. Currently, with the development of photosensitizer materials, phototherapy has been gradually applied to the treatment of NSCLC. This review provides an overview of recent advancements and limitations in different treatment strategies for NSCLC under the background of COVID-19. We discuss the latest advances in phototherapy as a promising treatment method for NSCLC. After critically examining the successes, challenges, and prospects associated with these treatment modalities, their profound prospects were portrayed.

Immune Checkpoint Inhibitors-Associated Diabetes and Ketoacidosis Were Found in FDA Adverse Event Reporting System: A Real-World Evidence Database Study

OBJECTIVE

To investigate the risk of developing diabetes and ketoacidosis in clinical patients with immune checkpoint inhibitors (ICIs).

METHODS

We looked in the FDA Adverse Event Reporting System for reports of ICIs-associated diabetes mellitus (DM) and ketoacidosis between January 2004 and March 2022. We explored the signals using fourfold table-based proportional imbalance algorithms. Patient characteristics, country distribution, and outcomes of adverse reactions were described. Kruskal-Wallis test was used to compare the time of onset and prognosis of adverse reactions.

RESULTS

A total of 2110 reports of ICIs-related DM were included in the study. The largest number of reports was from Japan (752, 35.64%), followed by the United States and France (624, 29.57%; 183, 8.67%). Seven drugs detected signals of DM and ketoacidosis according to 4 proportional imbalance algorithms: nivolumab, pembrolizumab, cemiplimab, dostarlimab, atezolizumab, avelumab, and durvalumab. Diabetes and ketoacidosis generally occurred early in the course of ICIs treatment, the median time to event onset was 144.5 (interquartile range 27-199) days. ICIs-related diabetes and ketoacidosis events resulted in 934 major medical events (44.3%), 524 hospitalizations (24.8%), 60 life-threatening events (2.8%), 42 deaths (2.0%), and 39 disability events (1.8%).

CONCLUSION

The study reveals the risk and characteristics of diabetes and ketoacidosis associated with ICIs, which may provide evidence for postmarketing evaluation. Careful consideration should be given to the possibility of an increased risk of diabetes and ketoacidosis after using ICIs, and careful monitoring for diabetes and ketoacidosis is recommended.

O-GlcNAc signaling: Implications for stress-induced adaptive response pathway in the tumor microenvironment

The tumor microenvironment (TME) consists of tumor cells, non-tumor cells, extracellular matrix, and signaling molecules, which can contribute to tumor initiation, progression, and therapy resistance. In response to starvation, hypoxia, and drug treatments, tumor cells undergo a variety of deleterious endogenous stresses, such as hypoxia, DNA damage, and oxidative stress. In this context, to survive the difficult situation, tumor cells evolve multiple conserved adaptive responses, including metabolic reprogramming, DNA damage checkpoints, homologous recombination, up-regulated antioxidant pathways, and activated unfolded protein responses. In the last decades, the protein O-GlcNAcylation has emerged as a crucial causative link between glucose metabolism and tumor progression. Here, we discuss the relevant pathways that regulate the above responses. These pathways are adaptive adjustments induced by endogenous stresses in cells. In addition, we systematically discuss the role of O-GlcNAcylation-regulated stress-induced adaptive response pathways (SARPs) in TME remodeling, tumor progression, and treatment resistance. We also emphasize targeting O-GlcNAcylation through compounds that modulate OGT or OGA activity to inhibit tumor progression. It seems that targeting O-GlcNAcylated proteins to intervene in TME may be a novel approach to improve tumor prognosis.

Case report: Malignant epithelioid angiosarcoma in a Chinese female patient

Perivascular epithelioid cell tumors (PEComas) are mesenchymal tumors that exhibit characteristic epithelioid or spindle cell morphology and typically grow around blood vessels. These tumors are characterized by the expression of melanocytic and smooth muscle markers, such as HMB-45, Melan-A, and smooth muscle actin, indicating a dual differentiation phenotype. PEComas are extremely rare diseases, and patients typically have a very poor prognosis. Here, we report a case of malignant cutaneous PEComa with pulmonary metastasis in a Chinese female and review relevant literature. The patient underwent surgical resection of a soft tissue tumor in the left upper arm under general anesthesia, and the subsequent pathological findings suggested a tumor with perivascular epithelioid cell differentiation (PEComa). The patient received adjuvant chemotherapy and radiotherapy after surgical resection, along with monitoring through computed tomography (CT) scans. Three months later, pulmonary metastasis was detected, but both the cutaneous PEComa in the left upper limb and the pulmonary metastatic lesions were stably controlled under active management and treatment. This is a rare case worth reporting and studying, and therefore, we conducted a long-term follow-up, and we hope to provide help for the clinical treatment of PEComa.

The expression of PD-L1 on tumor-derived exosomes enhances infiltration and anti-tumor activity of αCD3 × αPD-L1 bispecific antibody-armed T cells

Anti-cluster of differentiation (CD) 3 × α programmed death-ligand 1 (PD-L1) bispecific T-cell engager (BsTE)-bound T-cells (BsTE:T) are a promising new cancer treatment agent. However, the mechanisms of action of bispecific antibody-armed activated T-cells are poorly understood. Therefore, this study aimed to investigate the anti-tumor mechanism and efficacy of BsTE:T. The BsTE:T migration was assessed in vivo and in vitro using syngeneic and xenogeneic tumor models, flow cytometry, immunofluorescence staining, transwell migration assays, microfluidic chips, Exo View R100, western blotting, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 technology. In murine B16 melanoma, MC38 colon cancer, and human multiple myeloma cells, BsTE:T exhibited superior tumor elimination relative to that of T-cells or BsTE alone. Moreover, BsTE:T migration into tumors was significantly enhanced owing to the presence of PD-L1 in tumor cells and secretion of PD-L1-containing exosomes. Furthermore, increased infiltration of CD44highCD62Llow effector memory CD8+ T-cells into tumors was closely associated with the anti-tumor effect of BsTE:T. Therefore, BsTE:T is an innovative potential anti-tumor therapy, and exosomal PD-L1 plays a crucial role both in vitro and in vivo in the anti-tumor activity of BsTE:T.

PD-1/PD-L1 axis: implications in immune regulation, cancer progression, and translational applications

The PD-1/PD-L1 axis is a complex signaling pathway that has an important role in the immune system cells. Programmed cell death protein 1 (PD-1) acts as an immune checkpoint on the T lymphocytes, B lymphocytes, natural killer (NK), macrophages, dendritic cells (DCs), monocytes, and myeloid cells. Its ligand, the programmed cell death 1 ligand (PD-L1), is expressed in the surface of the antigen-presenting cells (APCs). The binding of both promotes the downregulation of the T cell response to ensure the activation to prevent the onset of chronic immune inflammation. This axis in the tumor microenvironment (TME) performs a crucial role in the tumor progression and the escape of the tumor by neutralizing the immune system, the engagement of PD-L1 with PD-1 in the T cell causes dysfunctions, neutralization, and exhaustion, providing the tumor mass production. This review will provide a comprehensive overview of the functions of the PD-1/PD-L1 system in immune function, cancer, and the potential therapeutic implications of the PD-1/PD-L1 pathway for cancer management.

Maternal Soluble Programmed Death Ligand-1 (sPD-L1) and T-regulatory Cells (Tregs) Alteration in Preeclampsia: A Cross-Sectional Study From Eastern India

Background Studies have shown that aberrant reactions of the immune system play an important role in the pathogenesis of preeclampsia. The immune checkpoint molecules programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) system and the T-regulatory cells (Tregs) system are decisive in the regulation of immune responses and can be the target molecules in preeclampsia. In this study, an attempt has been made to evaluate the soluble PD-L1 (sPD-L1) in the serum of preeclampsia cases and correlate it with Tregs and inflammatory markers to have an insight into the link between these immunomodulatory molecules in the pathogenesis of preeclampsia. Materials and methods Ten normal fertile women, 20 trimester-matched normal pregnancy cases, and 20 preeclampsia cases were enrolled in the study. Serum sPD-L1, transforming growth factor beta 1 (TGF-β1), and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). High-sensitive C-reactive protein (hsCRP) was estimated using a clinical biochemistry autoanalyzer. Tregs were evaluated using flow cytometry. Results and discussion The immune checkpoint molecule PD-L1 inversely correlated with Tregs in preeclampsia cases. Associated inflammation was seen by raised IL-6 and hsCRP. The breakdown of immunological tolerance is mainly caused by the dysregulating the Tregs/Th17 balance, which leads to conditions of autoimmunity and chronic inflammatory disorders. PD-L1 can be the link between this immunological misbalance. Conclusion Our study, showing an increase in sPD-L1 and TGF and a decrease in Tregs with an increase in inflammatory markers like IL-6 and hsCRP levels in preeclampsia, has potential implications for early diagnosis and management of the condition. PD-L1 and Tregs can be target molecules for early management of preeclampsia.

Emerging Therapeutic Targets and Future Directions in Advanced Gastric Cancer: A Comprehensive Review

Metastatic gastric cancer (GC) still represents a critical clinical challenge, with limited treatment options and a poor prognosis. Most patients are diagnosed at advanced stages, limiting the chances of surgery and cure. The identification of molecular targets and the possibility of combining immune checkpoint inhibitors with chemotherapy have recently reshaped the therapeutic landscape of metastatic gastric cancer. The new classification of gastric cancer, mainly based on immunologic and molecular criteria such as programmed cell death 1 (PD-1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), has made it possible to identify and differentiate patients who may benefit from immunotherapy, targeted therapy, or chemotherapy alone. All relevant and available molecular and immunological targets in clinical practice for the systemic treatment of this disease are presented. Particular attention is given to possible future approaches, including circulating tumor DNA (ctDNA) for therapeutic monitoring, new targeting agents against molecular pathways such as fibroblast growth factor receptor (FGFR) and MET, chimeric antigen receptor (CAR)-T cells, and cancer vaccines. This review aims to provide a comprehensive understanding of current targets in advanced gastric cancer and to offer valuable insights into future directions of research and clinical practice in this challenging disease.

Immune Checkpoint Inhibitors for Pediatric Cancers: Is It Still a Stalemate?

The knowledge surrounding the application of immune checkpoint inhibitors (ICIs) in the treatment of pediatric cancers is continuously expanding and evolving. These therapies work by enhancing the body's natural immune response against tumors, which may have been suppressed by certain pathways. The effectiveness of ICIs in treating adult cancers has been widely acknowledged. However, the results of early phase I/II clinical trials that exclusively targeted the use of ICIs for treating different pediatric cancers have been underwhelming. The response rates to ICIs have generally been modest, except for cases of pediatric classic Hodgkin lymphoma. There seems to be a notable disparity in the immunogenicity of childhood cancers compared to adult cancers, potentially accounting for this phenomenon. On average, childhood cancers tend to have significantly fewer neoantigens. In recent times, there has been a renewed sense of optimism regarding the potential benefits of ICI therapies for specific groups of children with cancer. In initial research, individuals diagnosed with pediatric hypermutated and SMARCB1-deficient cancers have shown remarkable positive outcomes when treated with ICI therapies. This is likely due to the underlying biological factors that promote the expression of neoantigens and inflammation within the tumor. Ongoing trials are diligently assessing the effectiveness of ICIs for pediatric cancer patients in these specific subsets. This review aimed to analyze the safety and effectiveness of ICIs in pediatric patients with different types of highly advanced malignancies.

Significance of PD-L1 and Tumor Microenvironment in Laryngeal Squamous Cell Cancer

BACKGROUND

Despite the considerable advancement in the field of medicine over recent decades, laryngeal cancer continues to be a challenge. The field of immune oncology has generated promising immunomodulation therapies and opened up new ways of treatment.

METHODS

Our retrospective study included 102 patients diagnosed with laryngeal squamous cell cancer (LSCC). Immunohistochemistry was used to evaluate the expression of PD-L1 and tumor microenvironment cells (CD4, CD8, CD68 and CD163).

RESULTS

PD-L1 expression showed statistically significant positive correlations with all examined tumor microenvironment cells. Patients with high CD68 and CD163 expression intratumorally (p = 0.0005 and p = 0.006, respectively) had statistically significant shorter disease-specific survival. Moreover, a statistically shorter time to recurrence was found in patients with high CD68 intratumoral and CD8 overall counts (p = 0.049 and p = 0.019, respectively). Also, high CD8 overall (>23%) and CD68 intratumoral (>2.7%) expression were statistically significant predictors of recurrence (p = 0.028, OR = 3.11 and p = 0.019, OR = 3.13, respectively).

CONCLUSIONS

Higher CD68 and CD163 expression represented significantly worse prognosticators for clinical outcomes in patients with LSCC. In order to determine which LSCC patients will benefit from anti-PD-1/PD-L1 inhibitors, it is crucial to elucidate the relationship between PD-L1 expression, immune cell distribution and prognosis in LSCC patients.

Microbiota-associated mechanisms in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide, ranking third in terms of incidence and second as a cause of cancer-related death. There is growing scientific evidence that the gut microbiota plays a key role in the initiation and development of CRC. Specific bacterial species and complex microbial communities contribute directly to CRC pathogenesis by promoting the neoplastic transformation of intestinal epithelial cells or indirectly through their interaction with the host immune system. As a result, a protumoural and immunosuppressive environment is created conducive to CRC development. On the other hand, certain bacteria in the gut microbiota contribute to protection against CRC. In this chapter, we analysed the relationship of the gut microbiota to CRC and the associations identified with specific bacteria. Microbiota plays a key role in CRC through various mechanisms, such as increased intestinal permeability, inflammation and immune system dysregulation, biofilm formation, genotoxin production, virulence factors and oxidative stress. Exploring the interaction between gut microbiota and tumourigenesis is essential for developing innovative therapeutic approaches in the fight against CRC.

Rational design of small-sized peptidomimetic inhibitors disrupting protein-protein interaction

Protein-protein interactions are fundamental to nearly all biological processes. Due to their structural flexibility, peptides have emerged as promising candidates for developing inhibitors targeting large and planar PPI interfaces. However, their limited drug-like properties pose challenges. Hence, rational modifications based on peptide structures are anticipated to expedite the innovation of peptide-based therapeutics. This review comprehensively examines the design strategies for developing small-sized peptidomimetic inhibitors targeting PPI interfaces, which predominantly encompass two primary categories: peptidomimetics with abbreviated sequences and low molecular weights and peptidomimetics mimicking secondary structural conformations. We have also meticulously detailed several instances of designing and optimizing small-sized peptidomimetics targeting PPIs, including MLL1-WDR5, PD-1/PD-L1, and Bak/Bcl-xL, among others, to elucidate the potential application prospects of these design strategies. Hopefully, this review will provide valuable insights and inspiration for the future development of PPI small-sized peptidomimetic inhibitors in pharmaceutical research endeavors.

Molecular glues for protein-protein interactions: Progressing toward a new dream

The modulation of protein-protein interactions with small molecules is one of the most rapidly developing areas in drug discovery. In this review, we discuss advances over the past decade (2014-2023) focusing on molecular glues (MGs)-monovalent small molecules that induce proximity, either by stabilizing native interactions or by inducing neomorphic interactions. We include both serendipitous and rational discoveries and describe the different approaches that were used to identify them. We classify the compounds in three main categories: degradative MGs, non-degradative MGs or PPI stabilizers, and MGs that induce self-association. Diverse, illustrative examples with structural data are described in detail, emphasizing the elements of molecular recognition and cooperative binding at the interface that are fundamental for a MG mechanism of action.

Targeted delivery of anti-miRNA21 sensitizes PD-L1high tumor to immunotherapy by promoting immunogenic cell death

Rationale: Growing evidence has demonstrated that miRNA-21 (miR-21) upregulation is closely associated with tumor pathogenesis. However, the mechanisms by which miR-21 inhibition modulates the immunosuppressive tumor microenvironment (TME) and improves tumor sensitivity to immune checkpoint blockade therapies remain largely unexplored. In this study, we demonstrate the precise delivery of anti-miR-21 using a PD-L1-targeting peptide conjugate (P21) to the PD-L1high TME. Methods: Investigating miR-21 inhibition mechanisms involved conducting quantitative real-time PCR, western blot, flow cytometry, and confocal microscopy analyses. The antitumor efficacy and immune profile of P21 monotherapy, or combined with anti-PD-L1 immune checkpoint inhibitors, were assessed in mouse models bearing CT26.CL25 tumors and 4T1 breast cancer. Results Inhibition of oncogenic miR-21 in cancer cells by P21 efficiently activates tumor suppressor genes, inducing autophagy and endoplasmic reticulum stress. Subsequent cell-death-associated immune activation (immunogenic cell death) is initiated via the release of damage-associated molecular patterns. The in vivo results also illustrated that the immunogenic cell death triggered by P21 could effectively sensitize the immunosuppressive TME. That is, P21 enhances CD8+ T cell infiltration in tumor tissues by conferring immunogenicity to dying cancer cells and promoting dendritic cell maturation. Meanwhile, combining P21 with an anti-PD-L1 immune checkpoint inhibitor elicits a highly potent antitumor effect in a CT26.CL25 tumor-bearing mouse model and 4T1 metastatic tumor model. Conclusions: Collectively, we have clarified a miR-21-related immunogenic cell death mechanism through the precise delivery of anti-miR-21 to the PD-L1high TME. These findings highlight the potential of miR-21 as a target for immunotherapeutic interventions.

Navigating through novelties concerning mCRC treatment-the role of immunotherapy, chemotherapy, and targeted therapy in mCRC

Over the course of nearly six decades since the inception of initial trials involving 5-FU in the treatment of mCRC (metastatic colorectal cancer), our progressive comprehension of the pathophysiology, genetics, and surgical techniques related to mCRC has paved the way for the introduction of novel therapeutic modalities. These advancements not only have augmented the overall survival but have also positively impacted the quality of life (QoL) for affected individuals. Despite the remarkable progress made in the last two decades in the development of chemotherapy, immunotherapy, and target therapies, mCRC remains an incurable disease, with a 5-year survival rate of 14%. In this comprehensive review, our primary goal is to present an overview of mCRC treatment methods following the latest guidelines provided by the National Comprehensive Cancer Network (NCCN), the American Society of Clinical Oncology (ASCO), and the American Society of Colon and Rectal Surgeons (ASCRS). Emphasis has been placed on outlining treatment approaches encompassing chemotherapy, immunotherapy, targeted therapy, and surgery's role in managing mCRC. Furthermore, our review delves into prospective avenues for developing new therapies, offering a glimpse into the future of alternative pathways that hold potential for advancing the field.

Tumor cells inhibit the activation of ILC2s through up-regulating PD-1 expression

OBJECTIVE

Up-regulating programmed cell death ligand-1(PD-L1) expressed on tumor cells and tumor-infiltrating myeloid cells interacting with up-regulated programmed cell death-1 (PD-1) expressed on tumor-infiltrating lymphoid cells greatly hinder their tumor-inhibiting effect. It is necessary to explore the deep mechanism of this negative effect, so as to find the potential methods to improve the immunotherapy efficiency.

METHODS AND RESULTS

In this study, we found that the PD-1 expression in lung cancer-infiltrating type II innate lymphoid cells (ILC2s) was highly up-regulated, which greatly restrained the activation and function of ILC2s. Furthermore, anti-PD-1 could restore the inhibition and effective cytokine secretion of ILC2s when co-cultured with tumor cells. In vivo studies proved that anti-PD-1 treatment promoted the activation of tumor-infiltrating ILC2s and inhibited the tumor growth of LLC-bearing nude mice.

DISCUSSION

Our studies demonstrate a new PD-1/PD-L1 axis regulating mechanism on innate immune cells, which provide a useful direction to ILC2s-based immunotherapy to cancer diseases.

The role of the immunosuppressive PD-1/PD-L1 checkpoint pathway in the aging process and age-related diseases

The accumulation of senescent cells within tissues is a hallmark of the aging process. Senescent cells are also commonly present in many age-related diseases and in the cancer microenvironment. The escape of abnormal cells from immune surveillance indicates that there is some defect in the function of cytotoxic immune cells, e.g., CD8+ T cells and natural killer (NK) cells. Recent studies have revealed that the expression of programmed death-ligand 1 (PD-L1) protein is abundantly increased in senescent cells. An increase in the amount of PD-L1 protein protects senescent cells from clearance by the PD-1 checkpoint receptor in cytotoxic immune cells. In fact, the activation of the PD-1 receptor suppresses the cytotoxic properties of CD8+ T and NK cells, promoting a state of immunosenescence. The inhibitory PD-1/PD-L1 checkpoint pathway acts in cooperation with immunosuppressive cells; for example, activation of PD-1 receptor can enhance the differentiation of regulatory T cells (Treg), myeloid-derived suppressor cells (MDSC), and M2 macrophages, whereas the cytokines secreted by immunosuppressive cells stimulate the expression of the immunosuppressive PD-L1 protein. Interestingly, many signaling pathways known to promote cellular senescence and the aging process are crucial stimulators of the expression of PD-L1 protein, e.g., epigenetic regulation, inflammatory mediators, mTOR-related signaling, cGAS-STING pathway, and AhR signaling. It seems that the inhibitory PD-1/PD-L1 immune checkpoint axis has a crucial role in the accumulation of senescent cells and thus it promotes the aging process in tissues. Thus, the blockade of the PD-1/PD-L1 checkpoint signaling might be a potential anti-aging senolytic therapy. KEY MESSAGES: Senescent cells accumulate within tissues during aging and age-related diseases. Senescent cells are able to escape immune surveillance by cytotoxic immune cells. Expression of programmed death-ligand 1 (PD-L1) markedly increases in senescent cells. Age-related signaling stimulates the expression of PD-L1 protein in senescent cells. Inhibitory PD-1/PD-L1 checkpoint pathway suppresses clearance of senescent cells.

Tissue fibroblasts are versatile immune regulators: An evaluation of their impact on the aging process

Fibroblasts are abundant stromal cells which not only control the integrity of extracellular matrix (ECM) but also act as immune regulators. It is known that the structural cells within tissues can establish an organ-specific immunity expressing many immune-related genes and closely interact with immune cells. In fact, fibroblasts can modify their immune properties to display both pro-inflammatory and immunosuppressive activities in a context-dependent manner. After acute insults, fibroblasts promote tissue inflammation although they concurrently recruit immunosuppressive cells to enhance the resolution of inflammation. In chronic pathological states, tissue fibroblasts, especially senescent fibroblasts, can display many pro-inflammatory and immunosuppressive properties and stimulate the activities of different immunosuppressive cells. In return, immunosuppressive cells, such as M2 macrophages and myeloid-derived suppressor cells (MDSC), evoke an excessive conversion of fibroblasts into myofibroblasts, thus aggravating the severity of tissue fibrosis. Single-cell transcriptome studies on fibroblasts isolated from aged tissues have confirmed that tissue fibroblasts express many genes coding for cytokines, chemokines, and complement factors, whereas they lose some fibrogenic properties. The versatile immune properties of fibroblasts and their close cooperation with immune cells indicate that tissue fibroblasts have a crucial role in the aging process and age-related diseases.

The role of ferroptosis in radiotherapy and combination therapy for head and neck squamous cell carcinoma (Review)

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive, heterogeneous tumour usually caused by alcohol and tobacco consumption, making it one of the most common malignancies worldwide. Despite the fact that various therapeutic approaches such as surgery, radiation therapy (RT), chemotherapy (CT) and targeted therapy have been widely used for HNSCC in recent years, its recurrence rate and mortality rate remain high. RT is the standard treatment choice for HNSCC, which induces reactive oxygen species production and causes oxidative stress, ultimately leading to tumour cell death. CT is a widely recognized form of cancer treatment that treats a variety of cancers by eliminating cancer cells and preventing them from reproducing. Immune checkpoint inhibitor and epidermal growth factor receptor are important in the treatment of recurrent or metastatic HNSCC. Iron death, a type of cell death regulated by peroxidative damage to phospholipids containing polyunsaturated fatty acids in cell membranes, has been found to be a relevant death response triggered by tumour RT in recent years. In the present review, an overview of the current knowledge on RT and combination therapy and iron death in HNSCC was provided, the mechanisms by which RT induces iron death in tumour cells were summarized, and therapeutic strategies to target iron death in HNSCC were explored. The current review provided important information for future studies of iron death in the treatment of HNSCC.

Nivolumab and Ipilimumab Acting as Tormentors of Advanced Tumors by Unleashing Immune Cells and Associated Collateral Damage

Combining immune checkpoint inhibitors, specifically nivolumab (anti-PD-1) and ipilimumab (anti-CTLA-4), holds substantial promise in revolutionizing cancer treatment. This review explores the transformative impact of these combinations, emphasizing their potential for enhancing therapeutic outcomes across various cancers. Immune checkpoint proteins, such as PD1 and CTLA4, play a pivotal role in modulating immune responses. Blocking these checkpoints unleashes anticancer activity, and the synergy observed when combining multiple checkpoint inhibitors underscores their potential for enhanced efficacy. Nivolumab and ipilimumab harness the host's immune system to target cancer cells, presenting a powerful approach to prevent tumor development. Despite their efficacy, immune checkpoint inhibitors are accompanied by a distinct set of adverse effects, particularly immune-related adverse effects affecting various organs. Understanding these challenges is crucial for optimizing treatment strategies and ensuring patient well-being. Ongoing clinical trials are actively exploring the combination of checkpoint inhibitory therapies, aiming to decipher their synergistic effects and efficacy against diverse cancer types. This review discusses the mechanisms, adverse effects, and various clinical trials involving nivolumab and ipilimumab across different cancers, emphasizing their transformative impact on cancer treatment.

The role of PD-1/PD-L1 signaling pathway in cancer pathogenesis and treatment: a systematic review

Aim: Cancer as a complex disease poses significant challenges for both diagnosis and treatment. Researchers have been exploring various avenues to find effective therapeutic strategies, with a particular emphasis on cellular signaling pathways and immunotherapy. One such pathway that has recently been suggested is the PD-1/PD-L1 pathway, which is an immune checkpoint signaling system that plays an important role in regulating the immune system and maintaining tissue homeostasis. Cancer cells exploit this pathway by producing PD-L1, which attaches to PD-1 on T cells, thus inhibiting immune responses and enabling the cancer cells to escape detection by the immune system. This study aimed to evaluate the role of the PD-1/PD-L1 pathway in cancer pathogenesis and treatment. Method: This study was performed based on the principles of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). All in vitro , in vivo , and clinical studies that were published in English have been considered during a thorough search of the Scopus, Web of Science, and PubMed databases without date restriction until March 2024. Results: According to the studies reviewed, the PD-1/PD-L1 signaling axis suggests promising therapeutic effects on various types of cancers such as non-small cell lung cancer, melanoma, breast cancer, hepatocellular carcinoma, squamous cell carcinoma, and colorectal cancer, among others. Additionally, research suggests that immune checkpoint inhibitors that block PD1/PD-L1, such as pembrolizumab, atezolizumab, nivolumab, durvalumab, cemiplimab, avelumab, etc. , can effectively prevent tumor cells from escaping the immune system. Moreover, there might be a possible interaction between microbiome, obesity, etc. on immune mechanisms and on the immune checkpoint inhibitors (ICIs). Conclusion: Although we have gained considerable knowledge about ICIs, we are still facing challenges in effectively prescribing the appropriate ICIs for individual patients. This is largely due to the complex interactions between different intracellular pathways, which need to be thoroughly studied. To resolve this issue, it is necessary to conduct more reliable clinical trials that can produce a scientific consensus.

The Role of αvβ3 Integrin in Cancer Therapy Resistance

A relevant challenge for the treatment of patients with neoplasia is the development of resistance to chemo-, immune-, and radiotherapies. Although the causes of therapy resistance are poorly understood, evidence suggests it relies on compensatory mechanisms that cells develop to replace specific intracellular signaling that should be inactive after pharmacological inhibition. One such mechanism involves integrins, membrane receptors that connect cells to the extracellular matrix and have a crucial role in cell migration. The blockage of one specific type of integrin is frequently compensated by the overexpression of another integrin dimer, generally supporting cell adhesion and migration. In particular, integrin αvβ3 is a key receptor involved in tumor resistance to treatments with tyrosine kinase inhibitors, immune checkpoint inhibitors, and radiotherapy; however, the specific inhibition of the αvβ3 integrin is not enough to avoid tumor relapse. Here, we review the role of integrin αvβ3 in tumor resistance to therapy and the mechanisms that have been proposed thus far. Despite our focus on the αvβ3 integrin, it is important to note that other integrins have also been implicated in drug resistance and that the collaborative action between these receptors should not be neglected.

TWIST1 Drives Cytotoxic CD8+ T-Cell Exhaustion through Transcriptional Activation of CD274 (PD-L1) Expression in Breast Cancer Cells

In breast cancer, epithelial-mesenchymal transition (EMT) is positively associated with programmed death ligand 1 (PD-L1) expression and immune escape, and TWIST1 silences ERα expression and induces EMT and cancer metastasis. However, how TWIST1 regulates PD-L1 and immune evasion is unknown. This study analyzed TWIST1 and PD-L1 expression in breast cancers, investigated the mechanism for TWIST1 to regulate PD-L1 transcription, and assessed the effects of TWIST1 and PD-L1 in cancer cells on cytotoxic CD8+ T cells. Interestingly, TWIST1 expression is correlated with high-level PD-L1 expression in ERα-negative breast cancer cells. The overexpression and knockdown of TWIST1 robustly upregulate and downregulate PD-L1 expression, respectively. TWIST1 binds to the PD-L1 promoter and recruits the TIP60 acetyltransferase complex in a BRD8-dependent manner to transcriptionally activate PD-L1 expression, which significantly accelerates the exhaustion and death of the cytotoxic CD8+ T cells. Accordingly, knockdown of TWIST1 or BRD8 or inhibition of PD-L1 significantly enhances the tumor antigen-specific CD8+ T cells to suppress the growth of breast cancer cells. These results demonstrate that TWIST1 directly induces PD-L1 expression in ERα-negative breast cancer cells to promote immune evasion. Targeting TWIST1, BRD8, and/or PD-L1 in ERα-negative breast cancer cells with TWIST1 expression may sensitize CD8+ T-cell-mediated immunotherapy.

PD-L1 Expression in Nonbacterial Chronic Cystitis and Bladder Cancer

INTRODUCTION AND HYPOTHESIS

The objective was to assess PD-L1 expression in nonbacterial chronic cystitis (NCC) and bladder cancer (BC).

METHODS

The present study included 20 NCC and 20 BC patients. The degree of inflammation of the bladder wall was assessed on slides stained with H&E. Viral pathogens (herpes simplex virus, Epstein-Barr virus, cytomegalovirus, and high-risk HPVs) were detected using real-time polymerase chain reaction analyses of the bladder specimens. Immunohistochemistry was performed to assess the PD-L1 expression in bladder tissue.

RESULTS

Expression of PD-L1 was detected in 40% of NCC patients and 85% of BC patients. Viral pathogens were found in 50% of NCC patients and 60% of BC patients, with EBV being the most common. In NCC patients the immune cell score correlated strongly with the degree of inflammatory infiltration of the bladder wall (r = 0.867, p < 0.001), the presence of lymphoid aggregates in the submucosa (r = 0.804, p < 0.001), koilocytosis (r = 0.620, p = 0.004), and the presence of viral pathogens (r = 0.784, p < 0.001). In BC patients the immune cell score correlated with the degree of inflammatory infiltration of the bladder wall (r = 0.534, p = 0.015) and the presence of viral pathogens (r = 0.626, p = 0.003), but not with the presence of lymphoid aggregates in the submucosa (r = 0.083, p = 0.729), and koilocytosis (r = 0.366, p = 0.112).

CONCLUSIONS

Expression of PD-L1 was detected in a cohort of NCC patients, although the PD-L1 positivity rate was lower than that in BC. Our results demonstrate that the degree of PD-L1 expression in bladder tissue is associated with the presence of viral infections and with the degree of inflammatory infiltration of the bladder wall in both NCC and BC.