miR-146a inhibits ovarian tumor growth in vivo via targeting immunosuppressive neutrophils and enhancing CD8+ T cell infiltration

Development of an innovative extracellular vesicle mimetic delivery platform for efficient miRNA delivery to tumours

Extracellular vesicles (EVs) display high degree of tissue tropism and therefore represent promising carriers for tissue-specific delivery of genes or drugs for the treatment of human diseases. However, current approaches for the loading of therapeutics into EVs have low entrapment efficiency and also do not adequately deplete endogenous EV content; thus, more effective approaches are needed. Here, we report an innovative EXtraCElluar vesicle surface Ligand-NanoParticles (EXCEL NPs), generated by transferring moieties of EVs onto the surface of synthetic nanoparticles. EXCEL NPs facilitate the efficient entrapment of therapeutics (89 % efficiency) and are completely devoid of pre-existing unwanted EV internal content. Importantly, we show that EXCEL NPs formulated using EVs derived from endothelial cells, astrocytes and macrophages retain the delivery characteristics of the original EVs. Using miRNA-146a as a model anti-cancer therapeutic, we further demonstrated successful delivery of miRNA-146a to IG10 orthotopic ovarian tumours in immune competent mice using EXCEL NPs formulated with macrophage-derived EVs. Our findings establish a new clinically translatable approach to leverage characteristics of endogenous EVs for therapeutic delivery. The versatility of the platform enables future application to different target cell types and therapeutic modalities.

p53: A player in the tumor microenvironment

Approximately half of all cancers have p53 inactivating mutations, in addition to which most malignancies inactivate the p53 pathway by increasing p53 inhibitors, decreasing p53 activators, or inactivating p53 downstream targets. A growing number of researches have demonstrated that p53 can influence tumor progression through the tumor microenvironment (TME). TME is involved in the process of tumor development and metastasis and affects the clinical prognosis of patients. p53 participates in host immunity and engages in the immune landscape of the TME, but the specific mechanisms remain to be investigated. This review briefly explores the interactions between different states of p53 and TME components and their mechanisms, as well as their effects on tumor progression. To understand the progress of drug development and clinical studies related to p53 and tumor microenvironment.

Inflammation and Immune Escape in Ovarian Cancer: Pathways and Therapeutic Opportunities

Ovarian cancer (OC) remains one of the most lethal gynecological malignancies, largely due to its late-stage diagnosis and high recurrence rates. Chronic inflammation is a critical driver of OC progression, contributing to immune evasion, tumor growth, and metastasis. Inflammatory cytokines, including IL-6, TNF-α, and IL-8, as well as key signaling pathways such as nuclear factor kappa B (NF-kB) and signal transducer and activator of transcription 3 (STAT3), are upregulated in OC, promoting a tumor-promoting environment. The tumor microenvironment (TME) is characterized by immune cells like tumor-associated macrophages (TAMs) and regulatory T cells (Tregs), which suppress anti-tumor immune responses, facilitating immune evasion. Furthermore, OC cells utilize immune checkpoint pathways, including PD-1/PD-L1, to inhibit cytotoxic T cell activity. Targeting these inflammatory and immune evasion mechanisms offers promising therapeutic strategies. COX-2 inhibitors, Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway blockers, and NF-kB inhibitors have shown potential in preclinical studies, while immune checkpoint inhibitors targeting PD-1/PD-L1 and CTLA-4 have been explored with mixed results in OC. Additionally, emerging research on the microbiome and inflammation-related biomarkers, such as microRNAs (miRNAs) and exosomes, points to new opportunities for early detection and precision medicine. Future approaches to OC treatment must focus on personalized strategies that target the inflammatory TME, integrating anti-inflammatory therapies with immunotherapy to enhance patient outcomes. Continued research into the interplay between inflammation and immune evasion in OC is essential for developing effective, long-lasting treatments.

Unraveling the interplay of CD8 + T cells and microRNA signaling in cancer: implications for immune dysfunction and therapeutic approaches

MicroRNAs (miRNAs) emerge as critical regulators of CD8 + T cell function within the complex tumor microenvironment (TME). This review explores the multifaceted interplay between miRNAs and CD8 + T cells across various cancers. We discuss how specific miRNAs influence CD8 + T cell activation, recruitment, infiltration, and effector function. Dysregulation of these miRNAs can contribute to CD8 + T cell exhaustion and immune evasion, hindering anti-tumor immunity. Conversely, manipulating miRNA expression holds promise for enhancing CD8 + T cell activity and improving cancer immunotherapy outcomes. We delve into the role of miRNAs in CD8 + T-cell function across different cancer types, including gliomas, gastric and colon cancer, oral squamous cell carcinoma, thyroid carcinoma, lymphomas, melanoma, breast cancer, renal cell carcinoma, ovarian cancer, uterine corpus endometrial cancer, bladder cancer, acute myeloid leukemia, chronic myelogenous leukemia, and osteosarcoma. Additionally, we explore how extracellular vesicles and cytokines modulate CD8 + T-cell function through complex interactions with miRNAs. Finally, we discuss the potential impact of radiotherapy and specific drugs on miRNA expression and CD8 + T-cell activity within the TME. This review highlights the immense potential of targeting miRNAs to manipulate CD8 + T-cell activity for the development of novel and improved cancer immunotherapies.

MiRNAs as Regulators of Immune Cells in the Tumor Microenvironment of Ovarian Cancer

Ovarian cancer is one of the leading causes of cancer deaths among women. There is an ongoing need to develop new biomarkers and targeted therapies to improve patient outcomes. One of the most critical research areas in ovarian cancer is identifying tumor microenvironment (TME) functions. TME consists of tumor-infiltrating immune cells, matrix, endothelial cells, pericytes, fibroblasts, and other stromal cells. Tumor invasion and growth depend on the multifactorial crosstalk between tumor cells and immune cells belonging to the TME. MiRNAs, which belong to non-coding RNAs that post-transcriptionally control the expression of target genes, regulate immune responses within the TME, shaping the landscape of the intrinsic environment of tumor cells. Aberrant expression of miRNAs may lead to the pathological dysfunction of signaling pathways or cancer cell-regulatory factors. Cell-to-cell communication between infiltrating immune cells and the tumor may depend on exosomes containing multiple miRNAs. MiRNAs may exert both immunosuppressive and immunoreactive responses, which may cause cancer cell elimination or survival. In this review, we highlighted recent advances in the field of miRNAs shaping the landscape of immune cells in the TME.

CXCL5 impedes CD8+ T cell immunity by upregulating PD-L1 expression in lung cancer via PXN/AKT signaling phosphorylation and neutrophil chemotaxis

BACKGROUND

Lung cancer remains one of the most prevalent cancer types worldwide, with a high mortality rate. Upregulation of programmed cell death protein 1 (PD-1) and its ligand (PD-L1) may represent a key mechanism for evading immune surveillance. Immune checkpoint blockade (ICB) antibodies against PD-1 or PD-L1 are therefore widely used to treat patients with lung cancer. However, the mechanisms by which lung cancer and neutrophils in the microenvironment sustain PD-L1 expression and impart stronger inhibition of CD8+ T cell function remain unclear.

METHODS

We investigated the role and underlying mechanism by which PD-L1+ lung cancer and PD-L1+ neutrophils impede the function of CD8+ T cells through magnetic bead cell sorting, quantitative real-time polymerase chain reaction (RT-PCR), western blotting, enzyme-linked immunosorbent assays, confocal immunofluorescence, gene silencing, flow cytometry, etc. In vivo efficacy and safety studies were conducted using (Non-obeseDiabetes/severe combined immune deficiency) SCID/NOD mice. Additionally, we collected clinical and prognostic data from 208 patients who underwent curative lung cancer resection between 2017 and 2018.

RESULTS

We demonstrated that C-X-C motif chemokine ligand 5 (CXCL5) is markedly overexpressed in lung cancer cells and is positively correlated with a poor prognosis in patients with lung cancer. Mechanistically, CXCL5 activates the phosphorylation of the Paxillin/AKT signaling cascade, leading to upregulation of PD-L1 expression and the formation of a positive feedback loop. Moreover, CXCL5 attracts neutrophils, compromising CD8+ T cell-dependent antitumor immunity. These PD-L1+ neutrophils aggravate CD8+ T cell exhaustion following lung cancer domestication. Combined treatment with anti-CXCL5 and anti-PD-L1 antibodies significantly inhibits tumor growth in vivo.

CONCLUSIONS

Our findings collectively demonstrate that CXCL5 promotes immune escape through PD-L1 upregulation in lung cancer and neutrophils chemotaxis through autocrine and paracrine mechanisms. CXCL5 may serve as a potential therapeutic target in synergy with ICBs in lung cancer immunotherapy.

Let-7i enhances anti-tumour immunity and suppresses ovarian tumour growth

Cancer immunotherapy has seen significant success in the last decade for cancer management by enhancing endogenous cancer immunity. However, immunotherapies developed thus far have seen limited success in the majority of high-grade serous carcinoma (HGSC) ovarian cancer patients. This is largely due to the highly immunosuppressive tumour microenvironment of HGSC and late-stage identification. Thus, novel treatment interventions are needed to overcome this immunosuppression and complement existing immunotherapies. Here, we have identified through analysis of > 600 human HGSC tumours a critical role for Let-7i in modulating the tumoural immune network. Tumoural expression of Let-7i had high positive correlation with anti-cancer immune signatures in HGSC patients. Confirming this role, enforced Let-7i expression in murine HGSC tumours resulted in a significant decrease in tumour burden with a significant increase in tumour T cell numbers in tumours. In concert with the improved tumoural immunity, Let-7i treatment also significantly increased CD86 expression in antigen presenting cells (APCs) in the draining lymph nodes, indicating enhanced APC activity. Collectively, our findings highlight an important role of Let-7i in anti-tumour immunity and its potential use for inducing an anti-tumour effect in HGSC.

Neutrophils at the Crossroads: Unraveling the Multifaceted Role in the Tumor Microenvironment

Over the past decade, research has prominently established neutrophils as key contributors to the intricate landscape of tumor immune biology. As polymorphonuclear granulocytes within the innate immune system, neutrophils play a pivotal and abundant role, constituting approximately ∼70% of all peripheral leukocytes in humans and ∼10-20% in mice. This substantial presence positions them as the frontline defense against potential threats. Equipped with a diverse array of mechanisms, including reactive oxygen species (ROS) generation, degranulation, phagocytosis, and the formation of neutrophil extracellular traps (NETs), neutrophils undeniably serve as indispensable components of the innate immune system. While these innate functions enable neutrophils to interact with adaptive immune cells such as T, B, and NK cells, influencing their functions, they also engage in dynamic interactions with rapidly dividing tumor cells. Consequently, neutrophils are emerging as crucial regulators in both pro- and anti-tumor immunity. This comprehensive review delves into recent research to illuminate the multifaceted roles of neutrophils. It explores their diverse functions within the tumor microenvironment, shedding light on their heterogeneity and their impact on tumor recruitment, progression, and modulation. Additionally, the review underscores their potential anti-tumoral capabilities. Finally, it provides valuable insights into clinical therapies targeting neutrophils, presenting a promising approach to leveraging innate immunity for enhanced cancer treatment.

Role of microRNAs in Immune Regulation with Translational and Clinical Applications

MicroRNAs (miRNAs) are 19-23 nucleotide long, evolutionarily conserved noncoding RNA molecules that regulate gene expression at the post-transcriptional level. In this review, involvement of miRNAs is summarized in the differentiation and function of immune cells, in anti-infective immune responses, immunodeficiencies and autoimmune diseases. Roles of miRNAs in anticancer immunity and in the transplantation of solid organs and hematopoietic stem cells are also discussed. Major focus is put on the translational clinical applications of miRNAs, including the establishment of noninvasive biomarkers for differential diagnosis and prediction of prognosis. Patient selection and response prediction to biological therapy is one of the most promising fields of application. Replacement or inhibition of miRNAs has enormous therapeutic potential, with constantly expanding possibilities. Although important challenges still await solutions, evaluation of miRNA fingerprints may contribute to an increasingly personalized management of immune dysregulation with a remarkable reduction in toxicity and treatment side effects. More detailed knowledge of the molecular effects of physical exercise and nutrition on the immune system may facilitate self-tailored lifestyle recommendations and advances in prevention.