PD-L1/PD-L1 signalling promotes colorectal cancer cell migration ability through RAS/MEK/ERK

An antibody targeting an immune checkpoint molecule BTN2A2 enhances anti-tumor immunity

Tumors exploit immune checkpoints to evade immune responses. Therefore, targeting these checkpoints has become a key strategy in cancer immunotherapy. In this study, we have developed a novel immune checkpoint inhibitor (ICI) targeting the B7 family-related molecule BTN2A2. The human BTN2A2 protein, which was highly expressed in some tumor tissues and activated antigen-presenting cells (APCs), can inhibit T cell activation and proliferation. The anti-BTN2A2 monoclonal antibody (mAb) can neutralize the inhibitory effect of BTN2A2 on T cells. In mouse models of pancreatic cancer and glioma, compared to the control group, the anti-BTN2A2 treatment group exhibited tumor shrinkage of 35.8 % (P < 0.05) and 51.2 % (P < 0.01), respectively, along with increased CD8+ tumor-infiltrating lymphocytes (TILs) by 1.7-fold (P < 0.001) and 2.2-fold (P < 0.001), respectively. In addition, anti-BTN2A2 mAb also increased the infiltration of B cells, M1 macrophages, and the expression of inflammatory cytokines in T cells, while reducing the infiltration of M2 macrophages, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs). Thus, anti-hBTN2A2 mAb normalizes the immunodeficient tumor microenvironment (TME) and inhibits tumor growth. Our results suggest that targeting the BTN2A2 immune checkpoint may represent a novel strategy for cancer treatment, especially in immunosuppressive 'cold' tumors.

Application of single-cell sequencing in the study of immune cell infiltration in inflammatory bowel disease and colorectal cancer

The rapid advancement of single-cell sequencing (SCS) technology has provided new insights into the relationship between inflammatory bowel disease (IBD) and colorectal cancer (CRC). This technique allows for detailed cellular analysis, enabling researchers to uncover the infiltration patterns of immune cells within the gut microenvironment and their roles in disease progression. This review summarizes significant research findings on the interplay between IBD and CRC, the characteristics of immune cell infiltration, and potential therapeutic targets identified through SCS. The aim is to offer references for future clinical studies and treatment strategies in this field.

Recent advances in biomimetic nanodelivery systems for cancer Immunotherapy

Tumor immunotherapy is a developing and promising therapeutic method. However, the mechanism of tumor immune microenvironment and individual differences of patients make the clinical application of immunotherapy still very limited. The resulting targeting of the tumor environment and immune system is a suitable strategy for tumor therapy. Biomimetic nanodelivery systems (BNDS) coated with nanoparticles has brought new hope for tumor immunotherapy. Due to its high targeting, maximum drug delivery efficiency and immune escape, BNDS has become one of the options for tumor immunotherapy in the future. BNDS combines the advantages of natural cell membranes and nanoparticles and has good targeting properties. This review summarizes the relationship between tumor and immune microenvironment, classification of immunotherapy, engineering modification of cell membrane, and a comprehensive overview of different types of membrane BNDS in immunotherapy. Furthermore, the prospects and challenges of biomimetic nanoparticles coated with membranes in tumor immunotherapy are further discussed.

Programmed Death-1 Ligand 1 Domain Organization, Signaling Motifs, and Interactors in Cancer Immunotherapy

Immunotherapies targeting the programmed cell death-1 ligand 1 (PD-L1) and programmed cell death 1 (PD-1) pathway sparked a revolution in cancer treatment. These breakthrough therapies work by disrupting the interaction between PD-1-expressed on T cells-and its ligand PD-L1, commonly found on the surface of cancer cells. By using monoclonal antibodies to block this binding, the immune system is unleashed to fight cancer more effectively. However, PD-L1's role extends far beyond immune evasion. When situated on cancer cells, PD-L1 transmits inhibitory signals through PD-1, silencing the effector functions of T cells. However, PD-L1 also engages in reverse signaling, also called intrinsic signaling, delivering intracellular instructions that contribute to cancer cell survival, even in the absence of PD-1 binding. This signaling cascade shields cancer cells from apoptosis, drives proliferation, regulates DNA damage responses, and even functions as a co-transcriptional transactivator, amplifying cancer's ability to thrive. The intricate mechanisms behind PD-L1's intrinsic signaling are under intense investigation. In this review, we provide a historical perspective on the discoveries leading to PD-L1's structure, signaling motifs, and interacting partners, shedding light on its multifaceted roles and the promising therapeutic possibilities ahead.

miR-186-5p Down-Regulates PD-L1 Level in Acute Myeloid Leukemia Cells and Inhibits Tumorigenesis and Immune Escape

Acute myeloid leukemia (AML) is a malignant tumor of blood cells, which seriously interferes with the generation of normal cells. Although miR-186-5p is diminished in AML, its exact mechanism is not well understood. miR-186-5p and PD-L1 levels in AML cells (HL-60, KG-1, TF-1a, MOLT-3) and subcutaneous tumor tissue were discovered through qRT-PCR and Western blot. miR-186-5 p and PD-L1 combining sites were foreseen by the database and verified by dual luciferase and immunoprecipitation experiments. AML cells with miR-186-5p overexpression or knockdown and PD-L1 overexpression were cocultured with CD4+ and CD8+ T cells. The proliferation, migration, invasion and apoptosis of AML cells, CD8+ and CD4+ T cell growth and apoptosis, and activated markers (Perforin and Granzyme B) and secreted cytokines (IFN-γ, IL-4 and TNF-α) levels were detected by CCK8, Transwell, flow cytometry, CFSE, Western blot and ELISA, respectively. Subcutaneous xenograft magnitude and mass in nude mice were measured. Ki67 level was identified through immunohistochemistry. CD4+ and CD8+ T cell level and infiltration were detected by immunofluorescence and flow cytometry. miR-186-5p was downregulated, and PD-L1 was boosted in AML cells and subcutaneous tumor tissues (p < 0.05), while miR-186-5p targeted down-regulate PD-L1. miR-186-5p upregulation hindered AML cell multiplication, migration, invasion and facilitate cell death, and enhanced the proliferation activity, activation markers (Perforin and Granzyme B) and secreted cytokines (IFN-γ, IL-4, TNF-α) of CD8+ and CD4+ T cells, inhibited apoptosis, and inhibited immune escape (p < 0.05). Knockdown of miR-186-5p can promote AML progression, but PD-L1 upregulation weakens the antitumor impact of miR-186-5p overexpression (p < 0.05). Transplanted tumor mice experiments also found that miR-186-5p hindered PD-L1 and tumor growth (p < 0.05). In conclusion, miR-186-5p can target inhibit PD-L1, suppress AML cells multiplication, movement, invasion and immune escape, and then reduce AML, aiming to provide support and basis for the pathological mechanism and prevention and treatment strategy of AML.

Influence of gut microbiota and immune markers in different stages of colorectal adenomas

Objective

Colorectal adenomas (CRA) are the primary precancerous lesions leading to colorectal cancer (CRC). Early detection and intervention of CRA can significantly reduce the incidence of CRC. We investigated the relationships between the gut microbiome and the expression levels of PD-L1, IL-6, and IFN-γ at different CRA stages.

Methods

Participants were divided into normal, non-advanced adenoma (NAA), and advanced adenoma (AA) groups. PD-L1 expression in collected tissues was analyzed via immunohistochemistry (IHC) and Western blotting. Serum IL-6 and IFN-γ levels were measured using Enzyme-Linked Immunosorbent Assay (ELISA). 16S rRNA gene sequencing was used to examine gut microbiota changes, with correlation analysis to assess microbial influences on CRA progression.

Results

The main differences in bacterial composition among the three groups were found within the Firmicutes and Bacteroidetes phyla. In the normal vs. NAA comparison, Clostridium sensu stricto, Faecalimonas, Gemmiger, and Ruminococcus were more abundant in the normal group, while Solobacterium was enriched in the NAA group. For the normal vs. AA comparison, the normal group was enriched with Anaerostipes, Blautia, Clostridium sensu stricto, Intestinibacter, Phocaeicola, and Turicibacter, whereas Solobacterium was more abundant in the AA group. In the NAA vs. AA comparison, the NAA group exhibited higher levels of Blautia, Faecalimonas, and Turicibacter relative to the AA group. Anaerostipes and Blautia are positively correlated with taurine and hypotaurine metabolism, propanoate metabolism, and zeatin biosynthesis. PD-L1 protein levels progressively increase with CRA advancement. Additionally, Faecalimonas, and Solobacterium were negatively associated with IFN-γ, while Gemmiger, and Anaerostipes were positively associated with IL-6.

Conclusion

This study highlights the dynamic alterations in gut microbiota composition and their potential influence on the regulation of inflammatory cytokines and PD-L1 expression during CRA progression. The enrichment of protective taxa, such as Anaerostipes and Blautia, in the normal group emphasizes their potential role in mitigating adenoma progression. Dietary modulation to promote the proliferation of these beneficial bacteria could serve as a promising strategy to improve colorectal health. Future research should further explore the specific relationships between dietary components, gut microbiota, and metabolic pathways, and assess the effects of dietary interventions on gut health.

Investigation the immunotherapeutic potential of miR-4477a targeting PD-1/PD-L1 in breast cancer cell line using a CD8+ co-culture model

BACKGROUND

In the present study, we investigated the immunotherapeutic and anticancer activities of microRNA-4477a (miR-4477a) as a PD-L1 inhibitor in breast cancer cells (MCF-7).

METHODS

To this end, a series of analytical procedures were conducted, including bioinformatic analysis, RT-PCR analysis, PD-L1 ELISA, in vitro co-culture analysis, cytotoxicity assays, cell migration assays, and colony formation assays, with the objective of determining the anticancer activity of the compound in question.

RESULTS

The results demonstrated that miR-4477a can bind to three distinct regions of PD-L1 mRNA with high scores (94%, 88% and 80%), effectively targeting and suppressing the crucial regulatory pathways of cancer cells. In vitro studies demonstrated that a 25 nM dose of miR-4477a caused relatively high cytotoxicity in the MCF-7 cell line, suppressed PD-L1 gene expression, and decreased sPD-L1 protein levels, strongly inhibited cell migration, and significantly reduced colony formation. The in vitro co-culture analysis revealed that cancer cells were unable to evade the surveillance and cytotoxic activity of T cells (CD8+) due to the blockade of PD-L1 expression by miR-4477a.

CONCLUSIONS

In conclusion, miRNA-4477a has the capacity to regulate immune responses in breast cancer cells and may therefore be a promising candidate for use in cancer immunotherapy as a therapeutic agent.

LncRNA SNHG16 Drives PD-L1-Mediated Immune Escape in Colorectal Cancer through Regulating miR-324-3p/ELK4 Signaling

Colorectal cancer (CRC) is a common malignancy that claims the life of many patients. Nucleolar RNA host gene 16 (SNHG16) has been identified as an oncogene in CRC development. However, the role and mechanism of SNHG16 in CRC remain unclear. A total of 27 cases of CRC tumor tissues and adjacent tissues were collected to investigate the expression and correlation among SNHG16, miR-324-3p, ELK4 and PD-L1 using qRT-PCR, western blot and Pearson analysis. Cell proliferation, migration and invasion abilities were determined using CCK-8 and transwell assays. The cytotoxicity of CD8 + T cells and the apoptosis of CD8+ T cells was evaluated by LDH assay and flow cytometry, respectively. Dual luciferase assay, RIP and ChIP methods were performed to verify molecular interactions. Our results showed that SNHG16, ELK4 and PD-L1 expression were abnormally elevated and miR-324-3p expression was decreased in tumor tissues from CRC patients and CRC cells. SNHG16 silencing resulted in suppression of cell growth, metastasis, and immune escape of CRC cells, which was reversed by miR-324-3p inhibitor and ELK4 overexpression. Mechanistically, SNHG16 acted as a competitive endogenous RNA to enhance ELK4 expression by sponging miR-324-3p, thereby provoking the transcription of PD-L1. Our results demonstrated that SNHG16 silencing led to the suppression of cell growth, metastasis, and immune escape of CRC cells through mediating miR-324-3p/ELK4/PD-L1 axis, offering promising targets for CRC treatment.

Baicalin attenuates PD-1/PD-L1 axis-induced immunosuppression in piglets challenged with Glaesserella parasuis by inhibiting the PI3K/Akt/mTOR and RAS/MEK/ERK signalling pathways

Infection of piglets with Glaesserella parasuis (G. parasuis) induces host immunosuppression. However, the mechanism underlying the immunosuppression of piglets remains unclear. Activation of the PD-1/PD-L1 axis has been shown to trigger host immunosuppression. Baicalin possesses anti-inflammatory and immunomodulatory functions. However, whether baicalin inhibits PD-1/PD-L1 activation and thus alleviates host immunosuppression has not been investigated. In this study, the effect of baicalin on the attenuation of piglet immunosuppression induced by G. parasuis was evaluated. Seventy piglets were randomly divided into the control group, infection group, levamisole group, BMS-1 group, 25 mg/kg baicalin group, 50 mg/kg baicalin group and 100 mg/kg baicalin group. Following pretreatment with levamisole, BMS-1 or baicalin, the piglets were challenged with 1 × 108 CFU of G. parasuis. Our results showed that baicalin, levamisole and BMS-1 modified routine blood indicators and biochemical parameters; downregulated IL-1β, IL-10, IL-18, TNF-α and IFN-γ mRNA expression; and upregulated IL-2 and IL-8 mRNA expression in blood. Baicalin, levamisole and BMS-1 increased the proportions of CD3+ T cells, CD3+CD4+ T cells, CD3+CD8+ T cells and CD3-CD21+ B cells in the splenocyte population, increased the proportions of CD3+ T cells, CD3+CD4+ T cells and CD3+CD8+ T cells in the blood, and inhibited PD-1/PD-L1 and TIM-3 activation. Baicalin, levamisole and BMS-1 reduced p-PI3K, p-Akt, and p-mTOR expression, the p-MEK1/2/MEK1/2 and p-ERK1/2/ERK1/2 ratios and increased RAS expression. Baicalin, levamisole and BMS-1 provided substantial protection against G. parasuis challenge and relieved tissue histopathological damage. Our findings might provide new strategies for controlling G. parasuis infection and other immunosuppressive diseases.

Hsa_circ_0004872 mitigates proliferation, metastasis and immune escape of meningioma cells by suppressing PD-L1

Meningioma is a prevalent intracranial malignancy known for its aggressive growth. Circular RNAs (circRNAs) play a crucial role in the development of various cancers. However, their involvement in meningioma remains understudied. This study aimed to investigate the function and underlying mechanism of hsa_circ_0004872 in meningioma. The molecular expression of hsa_circ_0004872, PD-L1 and EIF4A3 was identified by RT-qPCR and/or western blot assays. Cell viability, migration, and invasion were assessed through CCK-8 and Transwell assays, respectively. Cytotoxicity was determined using an LDH assay, and cell apoptosis was monitored by flow cytometry. The RNA and protein interactions were assessed through RNA-protein immunoprecipitation (RIP) and RNA pull down analyses. Our findings revealed that hsa_circ_0004872 expression was significantly downregulated in both meningioma tissue samples and cells. Overexpression of hsa_circ_0004872 inhibited the proliferation, metastasis, and immune escape of meningioma cells, as well as enhanced the cytotoxicity of CD8+ T cells by suppressing PD-L1. Furthermore, hsa_circ_0004872 directly interacted with EIF4A3, leading to the degradation of PD-L1 mRNA. Finally, inhibiting EIF4A3 improved the proliferation, metastasis, and immune escape of meningioma cells, as well as the cytotoxicity of CD8+ T cells. Our study demonstrated that hsa_circ_0004872 mitigated the proliferation, metastasis,and immune escape of meningioma cells by targeting the EIF4A3/PD-L1 axis. These findings suggested that hsa_circ_0004872 and EIF4A3 might serve as promising biological markers and therapeutic targets for meningioma treatment.

Immune checkpoints between epithelial-mesenchymal transition and autophagy: A conflicting triangle

Inhibitory immune checkpoint (ICP) molecules are pivotal in inhibiting innate and acquired antitumor immune responses, a mechanism frequently exploited by cancer cells to evade host immunity. These evasion strategies contribute to the complexity of cancer progression and therapeutic resistance. For this reason, ICP molecules have become targets for antitumor drugs, particularly monoclonal antibodies, collectively referred to as immune checkpoint inhibitors (ICI), that counteract such cancer-associated immune suppression and restore antitumor immune responses. Over the last decade, however, it has become clear that tumor cell-associated ICPs can also induce tumor cell-intrinsic effects, in particular epithelial-mesenchymal transition (EMT) and macroautophagy (hereafter autophagy). Both of these processes have profound implications for cancer metastasis and drug responsiveness. This article reviews the positive or negative cross-talk that tumor cell-associated ICPs undergo with autophagy and EMT. We discuss that tumor cell-associated ICPs are upregulated in response to the same stimuli that induce EMT. Moreover, ICPs themselves, when overexpressed, become an EMT-inducing stimulus. As regards the cross-talk with autophagy, ICPs have been shown to either stimulate or inhibit autophagy, while autophagy itself can either up- or downregulate the expression of ICPs. This dynamic equilibrium also extends to the autophagy-apoptosis axis, further emphasizing the complexities of cellular responses. Eventually, we delve into the intricate balance between autophagy and apoptosis, elucidating its role in the broader interplay of cellular dynamics influenced by ICPs. In the final part of this article, we speculate about the driving forces underlying the contradictory outcomes of the reciprocal, inhibitory, or stimulatory effects between ICPs, EMT, and autophagy. A conclusive identification of these driving forces may allow to achieve improved antitumor effects when using combinations of ICIs and compounds acting on EMT and/or autophagy. Prospectively, this may translate into increased and/or broadened therapeutic efficacy compared to what is currently achieved with ICI-based clinical protocols.

The pleiotropic enhancer enh9 promotes cell proliferation and migration in non-small cell lung cancer via ERMP1 and PD-L1

Enhancers, cis-acting DNA elements for transcriptional regulation, are important regulators of cell identity and disease. However, of the hundreds of thousands of enhancers annotated in the human genome, only a few have been studied for their regulatory mechanisms and functions in cancer progression and therapeutic resistance. Here, we report the pleiotropy of one enhancer (named enh9) in both cell proliferation and migration in non-small cell lung cancer (NSCLC) cells. By integrating multi-genomic data, ERMP1 and PD-L1 were screened out as potential targets of enh9. CUT&Tag sequencing demonstrated that enh9 was involved in the genomic interactions between the transcription factor RELA and the promoters of ERMP1 and PD-L1. In addition, ERMP1 and PD-L1 were validated to be involved in cell proliferation and migration, respectively. Our study fully elucidated the function and transcriptional regulation mechanisms of enh9 in NSCLC. The exploration on enhancers is promising to provide new insights for cancer diagnosis and therapy.

Reduced NCK1 participates in unexplained recurrent miscarriage by regulating trophoblast functions and macrophage proliferation at maternal-fetal interface

Recurrent miscarriage (RM) seriously affects the physical and mental health of women of childbearing age, and 50% of the causes are unknown. Thus, it is valuable to investigate the causes of unexplained recurrent miscarriage (uRM). Similarities between tumor development and embryo implantation make us realize that tumor studies are informative for uRM. The non-catalytic region of tyrosine kinase adaptor protein 1 (NCK1) is highly expressed in some tumors, and can promote tumor growth, invasion and migration. In this present paper, we firstly explore the role of NCK1 in uRM. We find that the NCK1 and PD-L1 are greatly reduced in peripheral blood mononuclear cells (PBMC) and decidua from patients with uRM. Next, we construct NCK1-knockdown HTR-8/SVneo cells, and find that NCK1-knockdown HTR-8/SVneo cells exhibit reduced proliferation and migration ability. Then we demonstrate that the expression of PD-L1 protein is decreased when the NCK1 is knocked down. In co-culture experiments with THP-1 and differently treated HTR-8/SVneo cells, we observe significantly increased proliferation of THP-1 in NCK1-knockdown group. In conclusion, NCK1 may be involved in RM by regulating trophoblast proliferation, migration, and regulating PD-L1-mediated macrophage proliferation at the maternal-fetal interface. Moreover, NCK1 has the potential to be a new predictor and therapeutic target.

Immune-related adverse events induced by programmed death protein-1 inhibitors from the perspective of lymphoma immunotherapy

Lymphoma, which is highly malignant, stems from lymph nodes and lymphoid tissue. Lymphoma cells express programmed death-ligand 1/2 (PD-L1/PD-L2), which binds with programmed cell death 1 protein (PD-1) to establish inhibitory signaling that impedes the normal function of T cells and allows tumor cells to escape immune system surveillance. Recently, immune checkpoint inhibitor immunotherapies such as PD-1 inhibitors (nivolumab and pembrolizumab) have been introduced into the lymphoma treatment algorithm and have shown remarkable clinical efficacy and greatly improve prognosis in lymphoma patients. Accordingly, the number of lymphoma patients who are seeking treatment with PD-1 inhibitors is growing annually, which results in an increasing number of patients developing immune-related adverse events (irAEs). The occurrence of irAEs inevitably affects the benefits provided by immunotherapy, particularly when PD-1 inhibitors are applied. However, the mechanisms and characteristics of irAEs induced by PD-1 inhibitors in lymphoma need further investigation. This review article summarizes the latest research advances in irAEs during treatment of lymphoma with PD-1 inhibitors. A comprehensive understanding of irAEs incurred in immunotherapy can help to achieve better efficacy with PD-1 inhibitors in lymphoma.

Recent Advancement of PD-L1 Detection Technologies and Clinical Applications in the Era of Precision Cancer Therapy

Programmed death-1 is a protein found on the surface of immune cells that can interact with its ligand, programmed death-ligand 1 (PD-L1), which is expressed on the plasma membrane, the surface of secreted cellular exosomes, in cell nuclei, or as a circulating soluble protein. This interaction can lead to immune escape in cancer patients. In clinical settings, PD-L1 plays an important role in tumor disease diagnosis, determining therapeutic effectiveness, and predicting patient prognosis. PD-L1 inhibitors are also essential components of tumor immunotherapy. Thus, the detection of PD-L1 levels is crucial, especially in the era of precision cancer therapy. In recent years, innovations have been made in traditional immunoassay methods and the development of new immunoassays for PD-L1 detection. This review aims to summarize recent research progress in tumor PD-L1 detection technology and highlight the clinical applications of PD-L1.