Suppression of PD-L1 release from small extracellular vesicles promotes systemic anti-tumor immunity by targeting ORAI1 calcium channels

Berberine synergises with ferroptosis inducer sensitizing NSCLC to ferroptosis in p53-dependent SLC7A11-GPX4 pathway

Berberine (BBR) is a compound derived from Chinese herbal medicine, known for its anticancer properties through multiple signaling pathways. However, whether BBR can inhibit tumor growth by participating in ferroptosis remains unconfirmed. In this study, we demonstrated that berberine synergistically inhibited NSCLC in combination with multiple ferroptosis inducers, and this combination synergistically down-regulated the mRNA and protein expression of SLC7A11, GPX4, and NRF2, resulting in ferroptosis accompanied by significant depletion of GSH, and aberrant accumulation of reactive oxygen species and malondialdehyde. In a lung cancer allograft model, the combination treatment exhibited enhanced anticancer effects compared to using either drug alone. Notably, p53 is critical in determining the ferroptosis sensitivity. We found that the combination treatment did not elicit a synergistic anticancer effect in cells with a p53 mutation or with exogenous expression of mutant p53. These findings provide insight into the mechanism by which combination induces ferroptosis and the regulatory role of p53 in this process. It may guide the development of new strategies for treating NSCLC, offering great medical potential for personal diagnosis and treatment.

Alix-normalized exosomal programmed death-ligand 1 analysis in urine enables precision monitoring of urothelial cancer

Anti-programmed death-ligand 1 (PD-L1) Ab-based therapies have demonstrated potential for treating metastatic urothelial cancer with high PD-L1 expression. Urinary exosomes are promising biomarkers for liquid biopsy, but urine's high variability requires normalization for accurate analysis. This study proposes using the PD-L1/Alix ratio to normalize exosomal PD-L1 signal intensity with Alix, an internal exosomal protein less susceptible to heterogeneity concerns than surface protein markers. Extracellular vesicles were isolated using ExoDisc and characterized using various methods, including ExoView to analyze tetraspanins, PD-L1, and Alix on individual exosomes. On-disc ELISA was used to evaluate PD-L1 and Alix-normalized PD-L1 in 15 urothelial cancer patients during the initial treatment cycle with Tecentriq. Results showed that Alix signal range was relatively uniform, whereas tetraspanin marker intensity varied for individual exosome particles. On-disc ELISA was more reliable for detecting exosomal PD-L1 expression than standard plate ELISA-based measurement. Using exosomal Alix expression for normalization is a more reliable approach than conventional methods for monitoring patient status. Overall, the study provides a practical and reliable method for detecting exosomal PD-L1 in urine samples from patients with urothelial cancer.

Spatiotemporal characteristics of tissue derived small extracellular vesicles is associated with tumor relapse and anti-PD-1 response

Small extracellular vesicles (sEVs) residing at tumor tissues are valuable specimens for biopsy. Tumor heterogeneity is common across all cancer types, but the heterogeneity of tumor tissue-derived sEVs (Ti-sEVs) is undefined. This study aims to discover the spatial distributions of Ti-sEVs in oral squamous cell carcinoma (OSCC) tissues and explore how these vesicle distributions affect the patients' prognosis. Multi-regional sampling enabled us to uncover that Ti-sEVs' accumulation at peritumoral sites correlates with a higher disease-free survival rate, and conversely, sparse peritumoral Ti-sEVs tend to forecast a higher risk of relapse. Of those relapsed patients, Ti-sEVs strongly bind to extracellular matrix and subsequently degrade it for allowing themselves enter the bloodstream rather than staying in situ. In advanced OSCC patients, the quantity and spatial distribution of Ti-sEVs prior to anti-PD-1 treatment, as well as the temporal variance of Ti-sEVs before and after immunotherapy, strongly map the clinical response and can help to distinguish the patients with shrinking tumors from those with growing tumors. Our work elucidates the correlation of spatiotemporal features of Ti-sEVs with patients' therapeutic outcomes and exhibit the potential for using Ti-sEVs as a predictor to forecast prognosis and screen the responders to anti-PD-1 therapy.

Application of exosomes in tumor immunity: recent progresses

Exosomes are small extracellular vesicles secreted by cells, ranging in size from 30 to 150 nm. They contain proteins, nucleic acids, lipids, and other bioactive molecules, which play a crucial role in intercellular communication and material transfer. In tumor immunity, exosomes present various functions while the following two are of great importance: regulating the immune response and serving as delivery carriers. This review starts with the introduction of the formation, compositions, functions, isolation, characterization, and applications of exosomes, and subsequently discusses the current status of exosomes in tumor immunotherapy, and the recent applications of exosome-based tumor immunity regulation and antitumor drug delivery. Finally, current challenge and future prospects are proposed and hope to demonstrate inspiration for targeted readers in the field.

ORAI Ca2+ Channels in Cancers and Therapeutic Interventions

The ORAI proteins serve as crucial pore-forming subunits of calcium-release-activated calcium (CRAC) channels, pivotal in regulating downstream calcium-related signaling pathways. Dysregulated calcium homeostasis arising from mutations and post-translational modifications in ORAI can lead to immune disorders, myopathy, cardiovascular diseases, and even cancers. Small molecules targeting ORAI present an approach for calcium signaling modulation. Moreover, emerging techniques like optogenetics and optochemistry aim to offer more precise regulation of ORAI. This review focuses on the role of ORAI in cancers, providing a concise overview of their significance in the initiation and progression of cancers. Additionally, it highlights state-of-the-art techniques for ORAI channel modulation, including advanced optical tools, potent pharmacological inhibitors, and antibodies. These novel strategies offer promising avenues for the functional regulation of ORAI in research and may inspire innovative approaches to cancer therapy targeting ORAI.

Identification of the exosomal PD-L1 inhibitor to promote the PD-1 targeting therapy of gastric cancer

Programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) targeting therapy is widely applied in clinics for gastric cancer treatment. Nevertheless, the clinical response is not well acceptable due to the exosomal PD-L1. Hence, abrogation of the exosomal PD-L1 may be a strategy to sensitize the gastric cancer cell to PD-1 targeting therapy. With the aid of CD63 targeting antibody and PD-L1 targeting aptamer, HTRF based assay was established to quantify the exosomal PD-L1, and applied to our in-house compound library, resulting in the identification of moclobemide. Further optimization of moclobemide lead to EP16, which can inhibit the generation of exosomal PD-L1 with IC50 = 0.108 μM. By applying EP16 to gastric cancer cell line coupled with T-cell activity related experiment, it was validated to activate T-cell and can promote the response of PD-1 targeting therapy for gastric cancer treatment in vitro and in vivo. Collectively, our findings give a promising tool to promote the sensitivity of anti-PD-1 for gastric cancer treatment, and EP16 can serve as a leading compound for exosomal PD-L1 abrogation.

Exosomes as Emerging Regulators of Immune Responses in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by high blood glucose levels resulting from insulin resistance and impaired insulin secretion. Immune dysregulation-mediated chronic low-grade inflammation is a critical factor that poses a significant risk to the metabolic disorders of T2DM and its related complications. Exosomes, as small extracellular vesicles secreted by various cells, have emerged as essential regulators of intercellular communication and immune regulation. In this review, we summarize the current understanding of the role of exosomes derived from immune and nonimmune cells in modulating immune responses in T2DM by regulating immune cell functions and cytokine production. More importantly, we suggest potential strategies for the clinical applications of exosomes in T2DM management, including biomarkers for disease diagnosis and monitoring, exosome-based therapies for drug delivery vehicles, and targeted therapy for exosomes.

Roles of exosomes in immunotherapy for solid cancers

Although immunotherapy has made breakthrough progress, its efficacy in solid tumours remains unsatisfactory. Exosomes are the main type of extracellular vesicles that can deliver various intracellular molecules to adjacent or distant cells and organs, mediating various biological functions. Studies have found that exosomes can both activate the immune system and inhibit the immune system. The antigen and major histocompatibility complex (MHC) carried in exosomes make it possible to develop them as anticancer vaccines. Exosomes derived from blood, urine, saliva and cerebrospinal fluid can be used as ideal biomarkers in cancer diagnosis and prognosis. In recent years, exosome-based therapy has made great progress in the fields of drug transportation and immunotherapy. Here, we review the composition and sources of exosomes in the solid cancer immune microenvironment and further elaborate on the potential mechanisms and pathways by which exosomes influence immunotherapy for solid cancers. Moreover, we summarize the potential clinical application prospects of engineered exosomes and exosome vaccines in immunotherapy for solid cancers. Eventually, these findings may open up avenues for determining the potential of exosomes for diagnosis, treatment, and prognosis in solid cancer immunotherapy.

Prostate cancer-derived small extracellular vesicle proteins: the hope in diagnosis, prognosis, and therapeutics

Current diagnostic tools for prostate cancer (PCa) diagnosis and risk stratification are insufficient. The hidden onset and poor efficacy of traditional therapies against metastatic PCa make this disease a heavy burden in global men's health. Prostate cancer-derived extracellular vesicles (PCDEVs) have garnered attention in recent years due to their important role in communications in tumor microenvironment. Recent advancements have demonstrated PCDEVs proteins play an important role in PCa invasion, progression, metastasis, therapeutic resistance, and immune escape. In this review, we briefly discuss the applications of sEV proteins in PCa diagnosis and prognosis in liquid biopsy, focus on the roles of the PCa-derived small EVs (sEVs) proteins in tumor microenvironment associated with cancer progression, and explore the therapeutic potential of sEV proteins applied for future metastatic PCa therapy.

Extracellular vesicles as biomarkers for AIDS-associated non-Hodgkin lymphoma risk

Introduction

Extracellular vesicles are membrane-bound structures secreted into the extracellular milieu by cells and can carry bioactive molecules. There is emerging evidence suggesting that EVs play a role in the diagnosis, treatment, and prognosis of certain cancers. In this study, we investigate the association of EVs bearing PD-L1 and molecules important in B-cell activation and differentiation with AIDS-NHL risk.

Methods

EVs were isolated from archived serum collected prior to the diagnosis of AIDS-NHL in cases (N = 51) and matched HIV+ controls (N = 52) who were men enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Serum specimens of AIDS-NHL cases were collected at a mean time of 1.25 years (range of 2 to 36 months) prior to an AIDS-NHL diagnosis. The expression of PD-L1 and other molecules on EVs (CD40, CD40L, TNF-RII, IL-6Rα, B7-H3, ICAM-1, and FasL) were quantified by Luminex multiplex assay.

Results and discussion

We observed significantly higher levels of EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα in AIDS-NHL cases compared with controls. Using multivariate conditional logistic regression models adjusted for age and CD4+ T-cell count, we found that EVs bearing PD-L1 (OR = 1.93; 95% CI: 1.10 - 3.38), CD40 (OR = 1.97, 95% CI: 1.09 - 3.58), TNF-RII (OR = 5.06; 95% CI: 1.99 - 12.85) and/or IL-6Rα (OR = 4.67; 95% CI: 1.40 - 15.53) were significantly and positively associated with AIDS-NHL risk. In addition, EVs bearing these molecules were significantly and positively associated with non-CNS lymphoma: PD-L1 (OR = 1.94; 95% CI: 1.01 - 3.72); CD40 (OR = 2.66; 95% CI: 1.12 - 6.35); TNF-RII (OR = 9.64; 95% CI: 2.52 - 36.86); IL-6Rα (OR = 8.34; 95% CI: 1.73 - 40.15). These findings suggest that EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα could serve as biomarkers for the early detection of NHL in PLWH.

Suppression of PD-L1 release from small extracellular vesicles promotes systemic anti-tumor immunity by targeting ORAI1 calcium channels

Blockade of immune checkpoints as a strategy of cancer cells to overcome the immune response has received ample attention in cancer research recently. In particular, expression of PD-L1 by various cancer cells has become a paradigm in this respect. Delivery of PD-L1 to its site of action occurs either by local diffusion, or else by transport via small extracellular vesicles (sEVs, commonly referred to as exosomes). Many steps of sEVs formation, their packaging with PD-L1 and their release into the extracellular space have been studied in detail. The likely dependence of release on Ca²⁺ -signaling, however, has received little attention. This is surprising, since the intracellular Ca²⁺ -concentration is known as a prominent regulator of many secretory processes. Here, we report on the roles of three Ca²⁺ -dependent proteins in regulating release of PD-L1-containing sEVs, as well as on the growth of tumors in mouse models. We show that sEVs release in cancer cell lines is Ca²⁺ -dependent and the knockdown of the gene coding the Ca²⁺ -channel protein ORAI1 reduces Ca²⁺ -signals and release of sEVs. Consequently, the T cell response is reinvigorated and tumor progression in mouse models is retarded. Furthermore, analysis of protein expression patterns in samples from human cancer tissue shows that the ORAI1 gene is significantly upregulated. Such upregulation is identified as an unfavorable prognostic factor for survival of patients with non-small-cell lung cancer. We show that reduced Ca²⁺ -signaling after knockdown of ORAI1 gene also compromises the activity of melanophilin and Synaptotagmin-like protein 2, two proteins, which are important for correct localization of secretory organelles within cancer cells and their transport to sites of exocytosis. Thus, the Ca²⁺ -channel ORAI1 and Ca²⁺ -dependent proteins of the secretion pathway emerge as important targets for understanding and manipulating immune checkpoint blockade by PD-L1.