A nanounit strategy reverses immune suppression of exosomal PD-L1 and is associated with enhanced ferroptosis

The link between intracellular calcium signaling and exosomal PD-L1 in cancer progression and immunotherapy

Exosomes are small membrane vesicles containing microRNA, RNA, DNA fragments, and proteins that are transferred from donor cells to recipient cells. Tumor cells release exosomes to reprogram the factors associated with the tumor microenvironment (TME) causing tumor metastasis and immune escape. Emerging evidence revealed that cancer cell-derived exosomes carry immune inhibitory molecule program death ligand 1 (PD-L1) that binds with receptor program death protein 1 (PD-1) and promote tumor progression by escaping immune response. Currently, some FDA-approved monoclonal antibodies are clinically used for cancer treatment by blocking PD-1/PD-L1 interaction. Despite notable treatment outcomes, some patients show poor drug response. Exosomal PD-L1 plays a vital role in lowering the treatment response, showing resistance to PD-1/PD-L1 blockage therapy through recapitulating the effect of cell surface PD-L1. To enhance therapeutic response, inhibition of exosomal PD-L1 is required. Calcium signaling is the central regulator of tumorigenesis and can regulate exosome biogenesis and secretion by modulating Rab GTPase family and membrane fusion factors. Immune checkpoints are also connected with calcium signaling and calcium channel blockers like amlodipine, nifedipine, lercanidipine, diltiazem, and verapamil were also reported to suppress cellular PD-L1 expression. Therefore, to enhance the PD-1/PD-L1 blockage therapy response, the reduction of exosomal PD-L1 secretion from cancer cells is in our therapeutic consideration. In this review, we proposed a therapeutic strategy by targeting calcium signaling to inhibit the expression of PD-L1-containing exosome levels that could reduce the anti-PD-1/PD-L1 therapy resistance and increase the patient's drug response rate.

Challenges Coexist with Opportunities: Spatial Heterogeneity Expression of PD-L1 in Cancer Therapy

Cancer immunotherapy using anti-programmed death-ligand 1 (PD-L1) antibodies has been used in various clinical applications and achieved certain results. However, such limitations as autoimmunity, tumor hyperprogression, and overall low patient response rate impede its further clinical application. Mounting evidence has revealed that PD-L1 is not only present in tumor cell membrane but also in cytoplasm, exosome, or even nucleus. Among these, the dynamic and spatial heterogeneous expression of PD-L1 in tumors is mainly responsible for the unsatisfactory efficacy of PD-L1 antibodies. Hence, numerous studies focus on inhibiting or degrading PD-L1 to improve immune response, while a comprehensive understanding of the molecular mechanisms underlying spatial heterogeneity of PD-L1 can fundamentally transform the current status of PD-L1 antibodies in clinical development. Herein, the concept of spatial heterogeneous expression of PD-L1 is creatively introduced, encompassing the structure and biological functions of various kinds of PD-L1 (including mPD-L1, cPD-L1, nPD-L1, and exoPD-L1). Then an in-depth analysis of the regulatory mechanisms and potential therapeutic targets of PD-L1 is provided, seeking to offer a solid basis for future investigation. Moreover, the current status of agents is summarized, especially small molecular modulators development directed at these new targets, offering a novel perspective on potential PD-L1 therapeutics strategies.

Semiconducting Polymers for Cancer Immunotherapy

As a monumental breakthrough in cancer treatment, immunotherapy has attracted tremendous attention in recent years. However, one challenge faced by immunotherapy is the low response rate and the immune-related adverse events (irAEs). Therefore, it is important to explore new therapeutic strategies and platforms for boosting therapeutic benefits and decreasing the side effects of immunotherapy. In recent years, semiconducting polymer (SP), a category of organic materials with π-conjugated aromatic backbone, has been attracting considerable attention because of their outstanding characteristics such as excellent photophysical features, good biosafety, adjustable chemical flexibility, easy fabrication, and high stability. With these distinct advantages, SP is extensively explored for bioimaging and photo- or ultrasound-activated tumor therapy. Here, the recent advancements in SP-based nanomedicines are summarized for enhanced tumor immunotherapy. According to the photophysical properties of SPs, the cancer immunotherapies enabled by SPs with the photothermal, photodynamic, or sonodynamic functions are highlighted in detail, with a particular focus on the construction of combination immunotherapy and activatable nanoplatforms to maximize the benefits of cancer immunotherapy. Herein, new guidance and comprehensive insights are provided for the design of SPs with desired photophysical properties to realize maximized effectiveness of required biomedical applications.

Targeting ferroptosis in melanoma: cancer therapeutics

Melanoma is an aggressive kind of skin cancer; its rate has risen rapidly over the past few decades. Melanoma reports for only about 1% of skin cancers but leads to a high majority of skin cancer deaths. Thus, new useful therapeutic approaches are currently required, to state effective treatments to consistently enhance the overall survival rate of melanoma patients. Ferroptosis is a recently identified cell death process, which is different from autophagy, apoptosis, necrosis, and pyroptosis in terms of biochemistry, genetics, and morphology which plays an important role in cancer treatment. Ferroptosis happens mostly by accumulating iron and lipid peroxides in the cell. Recently, studies have revealed that ferroptosis has a key role in the tumor's progression. Especially, inducing ferroptosis in cells can inhibit the tumor cells' growth, leading to back warding tumorigenesis. Here, we outline the ferroptosis characteristics from its basic role in melanoma cancer and mention its possible applications in melanoma cancer treatment. Video Abstract.

GW4869 Can Inhibit Epithelial-Mesenchymal Transition and Extracellular HSP90α in Gefitinib-Sensitive NSCLC Cells

Objective

GW4869 is an exosomal inhibitor. It is necessary to delay the occurrence of gefitinib resistance during non-small-cell lung cancer (NSCLC) treatment. This study aimed to investigate the anti-tumor effects of GW4869 on epithelial-mesenchymal transition (EMT) and expression of extracellular heat shock protein 90α (eHSP90α) that contributes to acquired resisitance. Our study provides a new sight into the treatment of EGFR-mutated NSCLC.

Materials and Methods

We performed western blotting to detect levels of EMT and eHSP90α. Wound healing and transwell assays were performed to evaluate the behavioral dynamics of EMT. A nude mouse model of HCC827 was established in vivo.

Results

GW4869 inhibited the expression of eHSP90α, EMT, invasion and migration abilities of HCC827 and PC9. GW4869 enhanced sensitivity to gefitinib in BALB/c nude mice bearing tumors of HCC827.

Conclusion

These studies suggest that GW4869 can inhibit EMT and extracellular HSP90α, providing new strategies for enhancing gefitinib sensitivity in NSCLC.

A STING pathway-activatable contrast agent for MRI-guided tumor immunoferroptosis synergistic therapy

The immunotherapy efficiency of stimulator of interferon genes (STING)-activatable drugs (e.g., 7-ethyl-10-hydroxycamptothecin, SN38) is limited by their non-specificity to tumor cells and the slow excretion of the DNA-containing exosomes from the treated cancer cells. The efficacy of tumor ferroptosis therapy is always limited by the elimination of lipid peroxides (LPO) by the pathways of glutathione peroxidase 4 (GPX4), dihydroorotate dehydrogenase (DHODH) and ferroptosis suppressor protein 1(FSP1). To solve these problems, in this study, we developed a STING pathway-activatable contrast agent (i.e., FeGd-HN@TA-Fe2+-SN38 nanoparticles) for magnetic resonance imaging (MRI)-guided tumor immunoferroptosis synergistic therapy. The remarkable in vivo MRI performance of FeGd-HN@TA-Fe2+-SN38 is attributed to its high accumulation at tumor location, the high relaxivities of FeGd-HN core, and the pH-sensitive TA-Fe2+-SN38 layer. The effectiveness and biosafety of the immunoferroptosis synergistic therapy induced by FeGd-HN@TA-Fe2+-SN38 are demonstrated by the in vivo investigations on the 4T1 tumor-bearing mice. The mechanisms of in vivo immunoferroptosis synergistic therapy by FeGd-HN@TA-Fe2+-SN38 are demonstrated by measurements of in vivo ROS, LPO, GPX4 and SLC7A11 levels, the intratumor matured DCs and CD8+ T cells, the protein expresion of STING and IRF-3, and the secretion of IFN-β and IFN-γ.

Exosomes in Cancer Progression and Therapy Resistance: Molecular Insights and Therapeutic Opportunities

The development of therapy resistance still represents a major hurdle in treating cancers, leading to impaired treatment success and increased patient morbidity. The establishment of minimally invasive liquid biopsies is a promising approach to improving the early diagnosis, as well as therapy monitoring, of solid tumors. Because of their manifold functions in the tumor microenvironment, tumor-associated small extracellular vesicles, referred to as exosomes, have become a subject of intense research. Besides their important roles in cancer progression, metastasis, and the immune response, it has been proposed that exosomes also contribute to the acquisition and transfer of therapy resistance, mainly by delivering functional proteins and RNAs, as well as facilitating the export of active drugs or functioning as extracellular decoys. Extensive research has focused on understanding the molecular mechanisms underlying the occurrence of resistance and translating these into strategies for early detection. With this review, we want to provide an overview of the current knowledge about the (patho-)biology of exosomes, as well as state-of-the-art methods of isolation and analysis. Furthermore, we highlight the role of exosomes in tumorigenesis and cancer treatment, where they can function as therapeutic agents, biomarkers, and/or targets. By focusing on their roles in therapy resistance, we will reveal new paths of exploiting exosomes for cancer diagnosis and treatment.

Ferroptosis-related STEAP3 acts as predictor and regulator in diffuse large B cell lymphoma through immune infiltration

Diffuse large B cell lymphoma (DLBCL) is a usual-seen hematological malignant tumor possessing molecular and genetic heterogeneity. Ferroptosis induction has been increasingly acknowledged to be an advantageous therapeutic method in tumor treatment by triggering cell death of tumor cells. However, studies on the function of ferroptosis in DLBCL remain scarce, especially the interaction with the tumor immune microenvironment (TIME). The clinical and biological functions of ferroptosis-related genes in DLBCL were still warranted to be explored. A ferroptosis-related risk model was constructed, followed by functional enrichment analyses and evaluation of immune profile. Quantitative real-time PCR, western blotting, and immunohistochemistry were conducted to examine the RNA and protein levels. Dysregulated expression of the major ferroptosis-related genes was found in DLBCL. A prognostic risk model based on 10 ferroptosis-related genes was constructed. The risk score served as an independent prognostic indicator for DLBCL patients in univariate and multivariate Cox regression analysis. Patients with low-risk scores presented a more favorable prognosis. Functional enrichment analysis revealed that immune-related pathways were significantly enriched, and the high-risk group exhibited less immunocyte infiltration, lower immunoscore, and downregulated PD-L1 expression relative to the low-risk group. Two molecular subtypes were determined through consensus clustering of the expression of ferroptosis-related genes. Cluster 1 was relevant to favorable prognosis, higher immunoscore, and elevated PD-L1 expression. More importantly, STEAP3 was screened as a reliable biomarker for DLBCL, and its enhanced expression levels of mRNA and protein were verified in public databases and clinical specimens. Our study demonstrated the crucial role of ferroptosis-related genes including STEAP3 in the TIME of DLBCL and identified promising novel molecular targets for DLBCL treatment.

Ferroptosis as a promising therapeutic strategy for melanoma

Malignant melanoma (MM) is the most common and deadliest type of skin cancer and is associated with high mortality rates across all races and ethnicities. Although present treatment options combined with surgery provide short-term clinical benefit in patients and early diagnosis of non-metastatic MM significantly increases the probability of survival, no efficacious treatments are available for MM. The etiology and pathogenesis of MM are complex. Acquired drug resistance is associated with a pool prognosis in patients with advanced-stage MM. Thus, these patients require new therapeutic strategies to improve their treatment response and prognosis. Multiple studies have revealed that ferroptosis, a non-apoptotic form of regulated cell death (RCD) characterized by iron dependant lipid peroxidation, can prevent the development of MM. Recent studies have indicated that targeting ferroptosis is a promising treatment strategy for MM. This review article summarizes the core mechanisms underlying the development of ferroptosis in MM cells and its potential role as a therapeutic target in MM. We emphasize the emerging types of small molecules inducing ferroptosis pathways by boosting the antitumor activity of BRAFi and immunotherapy and uncover their beneficial effects to treat MM. We also summarize the application of nanosensitizer-mediated unique dynamic therapeutic strategies and ferroptosis-based nanodrug targeting strategies as therapeutic options for MM. This review suggests that pharmacological induction of ferroptosis may be a potential therapeutic target for MM.

Advances in hyperbaric oxygen to promote immunotherapy through modulation of the tumor microenvironment

Hyperbaric oxygen therapy is a relatively safe treatment method that has been used for a long time in the clinic. It has been proven that it can enhance the sensitivity of radiotherapy and photodynamic therapy for cancer. However, there are few studies on hyperbaric oxygen and immunotherapy. In this article, we summarize that hyperbaric oxygen therapy regulates the tumor microenvironment through various pathways such as improving tumor hypoxia, targeting hypoxia-inducing factors, and generating reactive oxygen species. The change in the tumor microenvironment ultimately affects the curative effect of immunotherapy. Therefore, hyperbaric oxygen can influence immunotherapy by regulating the tumor microenvironment, providing a direction for the future development of immunotherapy.

Protocol for evaluation of tumor-derived exosome-induced cancer cell metastasis in a mouse model

Exosomes mediate intracellular communication between cancer cells and the local/distant microenvironment, which promotes systemic dissemination of cancer. Here, we present a protocol for tumor-derived exosome isolation and in vivo metastasis evaluation in a mouse model. We describe steps for isolating and characterizing exosomes, establishing a metastatic mouse model, and injecting exosomes into mouse. We then detail hematoxylin and eosin staining and analysis. This protocol can be used to investigate exosome function and identify unexplored metastatic regulators related to exosome biogenesis. For complete details on the use and execution of this protocol, please refer to Lee et al. (2023).1.

Maltol has anti-cancer effects via modulating PD-L1 signaling pathway in B16F10 cells

Introduction: Among skin cancers, melanoma has a high mortality rate. Recent advances in immunotherapy, particularly through immune checkpoint modulation, have improved the clinical treatment of melanoma. Maltol has various bioactivities, including anti-oxidant and anti-inflammatory properties, but the anti-melanoma property of maltol remains underexplored. The aim of this work is to explore the anti-melanoma potential of maltol through regulating immune checkpoints. Methods: The immune checkpoint PD-L1 was analyzed using qPCR, immunoblots, and immunofluorescence. Melanoma sensitivity towards T cells was investigated via cytotoxicity, cell viability, and IL-2 assays employing CTLL-2 cells. Results: Maltol was found to reduce melanin contents, tyrosinase activity, and expression levels of tyrosinase and tyrosinase-related protein 1. Additionally, maltol suppressed the proliferative capacity of B16F10 and induced cell cycle arrest. Maltol increased apoptotic rates by elevating cleaved caspase-3 and PARP. The co-treatment with maltol and cisplatin revealed a synergistic effect on inhibiting growth and promoting apoptosis. Maltol suppressed IFN-γ-induced PD-L1 and cisplatin-upregulated PD-L1 by attenuating STAT1 phosphorylation, thereby enhancing cisplatin's cytotoxicity against B16F10. Maltol augmented sensitivity to CTLL-2 cell-regulated melanoma destruction, leading to an increase in IL-2 production. Discussion: These findings demonstrate that maltol restricts melanoma growth through the downregulation of PD-L1 and elicits T cell-mediated anti-cancer responses, overcoming PD-L1-mediated immunotherapy resistance of cisplatin. Therefore, maltol can be considered as an effective therapeutic agent against melanoma.

ExoPD-L1: an assistant for tumor progression and potential diagnostic marker

The proliferation and function of immune cells are often inhibited by the binding of programmed cell-death ligand 1 (PD-L1) to programmed cell-death 1 (PD-1). So far, many studies have shown that this combination poses significant difficulties for cancer treatment. Fortunately, PD-L1/PD-1 blocking therapy has achieved satisfactory results. Exosomes are tiny extracellular vesicle particles with a diameter of 40~160 nm, formed by cells through endocytosis. The exosomes are a natural shelter for many molecules and an important medium for information transmission. The contents of exosomes are composed of DNA, RNA, proteins and lipids etc. They are crucial to antigen presentation, tumor invasion, cell differentiation and migration. In addition to being present on the surface of tumor cells or in soluble form, PD-L1 is carried into the extracellular environment by tumor derived exosomes (TEX). At this time, the exosomes serve as a medium for communication between tumor cells and other cells or tissues and organs. In this review, we will cover the immunosuppressive role of exosomal PD-L1 (ExoPD-L1), ExoPD-L1 regulatory factors and emerging approaches for quantifying and detecting ExoPD-L1. More importantly, we will discuss how targeted ExoPD-L1 and combination therapy can be used to treat cancer more effectively.

Hydrogen Sulfide Gas Amplified ROS Cascade: FeS@GOx Hybrid Nanozyme Designed for Boosting Tumor Chemodynamic Immunotherapy

Chemodynamic immunotherapy that utilizes catalysts to produce reactive oxygen species (ROS) for killing tumor cells and arousing antitumor immunity has received considerable attention. However, it is still restricted by low ROS production efficiency and insufficient immune activation, due to intricate redox homeostasis in the tumor microenvironment (TME). Herein, a metalloprotein-like hybrid nanozyme (FeS@GOx) is designed by in situ growth of nanozyme (ferrous sulfide, FeS) in a natural enzyme (glucose oxidase, GOx) to amplify ROS cascade for boosting chemodynamic immunotherapy. In FeS@GOx, GOx allows the conversion of endogenous glucose to gluconic acid and hydrogen peroxide, which provides favorable increasing hydrogen peroxide for subsequent Fenton reaction of FeS nanozymes, thus reinforcing ROS production. Notably, hydrogen sulfide (H2 S) release is activated by the gluconic acid generation-related pH decrease, which can suppress the activity of endogenous thioredoxin reductase and catalase to further inhibit ROS elimination. Thus, FeS@GOx can sustainably amplify ROS accumulation and perturb intracellular redox homeostasis to improve chemodynamic therapy and trigger robust immunogenic cell death for effective immunotherapy combined with immune checkpoint blockade. This work proposes a feasible H2 S amplified ROS cascade strategy employing a bioinspired hybrid nanozyme, providing a novel pathway to multi-enzyme-mediated TME modulation for precise and efficient chemodynamic immunotherapy.

Polysaccharide hydrogel platforms as suitable carriers of liposomes and extracellular vesicles for dermal applications

Lipid-based nanocarriers have been extensively investigated for their application in drug delivery. Particularly, liposomes are now clinically established for treating various diseases such as fungal infections. In contrast, extracellular vesicles (EVs) - small cell-derived nanoparticles involved in cellular communication - have just recently sparked interest as drug carriers but their development is still at the preclinical level. To drive this development further, the methods and technologies exploited in the context of liposome research should be applied in the domain of EVs to facilitate and accelerate their clinical translation. One of the crucial steps for EV-based therapeutics is designing them as proper dosage forms for specific applications. This review offers a comprehensive overview of state-of-the-art polysaccharide-based hydrogel platforms designed for artificial and natural vesicles with application in drug delivery to the skin. We discuss their various physicochemical and biological properties and try to create a sound basis for the optimization of EV-embedded hydrogels as versatile therapeutic avenues.

Function and clinical application of exosome-how to improve tumor immunotherapy?

In recent years, immunotherapy has been increasingly used in clinical practice to treat tumors. However, immunotherapy's efficacy varies between tumor types and patient populations, and long-term drug resistance often occurs during treatment. Therefore, it is essential to explore the molecular mechanisms of immunotherapy to improve its efficacy. In this review, we focus on the significance of tumor-derived exosomes in the clinical treatment of tumors and how modifying these exosomes may enhance immune effectiveness. Specifically, we discuss exosome components, such as RNA, lipids, and proteins, and the role of membrane molecules on exosome surfaces. Additionally, we highlight the importance of engineered exosomes for tumor immunotherapy. Our goal is to propose new strategies to improve the efficacy of tumor immunotherapy.

Hydrazide/Metal/Indocyanine Green Coordinated Nanoplatform for Potentiating Reciprocal Ferroptosis and Immunity against Melanoma

Ferroptosis holds great potential in cancer treatment, but its efficacy is severely limited by a low Fenton reaction efficacy. Meanwhile, the interactive relationship between Ferroptosis and the PD-1 blockade is still vague. Herein, a hydrazide/Cu/Fe/indocyanine green coordinated nanoplatform (TCFI) is constructed by a hydrazide-metal-sulfonate coordination process. The TCFI nanoplatform exhibits Fenton-/catalase-/glutathione oxidase-like triple activities and accordingly can trigger lipid peroxidation, relieve hypoxia, and downregulate the glutathione/glutathione peroxidase 4 axis, thus achieving positively and negatively dually enhanced Ferroptosis in B16F10 cancer cells. Under near-infrared laser irradiation, the TCFI nanoplatform induces robust immunogenic cancer cell death by elevating the intracellular reactive oxygen species level through synergistic photodynamic therapy/Ferroptosis, which significantly potentiates CD8+ T cell infiltration into tumors and interferon-γ secretion. Moreover, upregulated interferon-γ efficiently inhibits system xc- activity and sensitizes cancer cells to Ferroptosis. Interestingly, the PD-1 blockade may strengthen the reciprocal process. The combination of the TCFI nanoplatform and αPD-1 can eliminate primary tumors and inhibit distant tumor growth, lung metastasis, and tumor recurrence. This study presents a simple and novel coordination strategy to fabricate tumor microenvironment-responsive nanodrugs and highlights the enhancement effect of photodynamic therapy on reciprocal Ferroptosis and antitumor immunity.

MAT1A Suppression by the CTBP1/HDAC1/HDAC2 Transcriptional Complex Induces Immune Escape and Reduces Ferroptosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains a significant health burden globally due to its high prevalence and morbidity. C-terminal-binding protein 1 (CTBP1) is a transcriptional corepressor that modulates gene transcription by interacting with transcription factors or chromatin-modifying enzymes. High CTBP1 expression has been associated with the progression of various human cancers. In this study, bioinformatics analysis suggested the existence of a CTBP1/histone deacetylase 1 (HDAC1)/HDAC2 transcriptional complex that regulates the expression of methionine adenosyltransferase 1A (MAT1A), whose loss has been associated with ferroptosis suppression and HCC development. Thus, this study aims to investigate the interactions between the CTBP1/HDAC1/HDAC2 complex and MAT1A and their roles in HCC progression. First, high expression of CTBP1 was observed in HCC tissues and cells, where it promoted HCC cell proliferation and mobility while inhibiting cell apoptosis. CTBP1 interacted with HDAC1 and HDAC2 to suppress the MAT1A transcription, and silencing of either HDAC1 or HDAC2 or overexpression of MAT1A led to the inhibition of cancer cell malignancy. In addition, MAT1A overexpression resulted in increased S-adenosylmethionine levels, which promoted ferroptosis of HCC cells directly or indirectly by increasing CD8+ T-cell cytotoxicity and interferon-γ production. In vivo, MAT1A overexpression suppressed growth of CTBP1-induced xenograft tumors in mice while enhancing immune activity and inducing ferroptosis. However, treatment with ferrostatin-1, a ferroptosis inhibitor, blocked the tumor-suppressive effects of MAT1A. Collectively, this study reveals that the CTBP1/HDAC1/HDAC2 complex-induced MAT1A suppression is liked to immune escape and reduced ferroptosis of HCC cells.

Ferroptosis: a novel regulated cell death participating in cellular stress response, radiotherapy, and immunotherapy

BACKGROUND

Ferroptosis is a regulated cell death mode triggered by iron-dependent toxic membrane lipid peroxidation. As a novel cell death modality that is morphologically and mechanistically different from other forms of cell death, such as apoptosis and necrosis, ferroptosis has attracted extensive attention due to its association with various diseases. Evidence on ferroptosis as a potential therapeutic strategy has accumulated with the rapid growth of research on targeting ferroptosis for tumor suppression in recent years.

METHODS

We summarize the currently known characteristics and major regulatory mechanisms of ferroptosis and present the role of ferroptosis in cellular stress responses, including ER stress and autophagy. Furthermore, we elucidate the potential applications of ferroptosis in radiotherapy and immunotherapy, which will be beneficial in exploring new strategies for clinical tumor treatment.

RESULT AND CONCLUSION

Based on specific biomarkers and precise patient-specific assessment, targeting ferroptosis has great potential to be translated into practical new approaches for clinical cancer therapy, significantly contributing to the prevention, diagnosis, prognosis, and treatment of cancer.

Therapeutic effects of human umbilical cord mesenchymal stem cell-derived extracellular vesicles on ovarian functions through the PI3K/Akt cascade in mice with premature ovarian failure

Premature ovarian failure (POF) mainly refers to ovarian dysfunction in females younger than forty. Mesenchymal stem cells (MSCs) are considered an increasingly promising therapy for POF. This study intended to uncover the therapeutic effects of human umbilical cord MSC-derived extracellular vesicles (hucMSCEVs) on POF. hucMSCs were identified by observing morphology and examining differentiation capabilities. EVs were extracted from hucMSCs and later identified utilizing nanoparticle tracking analysis, transmission electron microscopy, and Western blotting. POF mouse models were established by injecting D-galactose (Dgal). The estrous cycles were assessed through vaginal cytology, and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-mullerian hormone (AMH), estradiol (E2), and progesterone (P) were measured by ELISA. The human ovarian granulosa cell line KGN was used for in vitro experiments. The uptake of hucMSC-EVs by KGN cells was detected. After D-gal treatment, cell proliferation and apoptosis were assessed via CCK-8 assay and flow cytometry. The PI3K/Akt pathway-related proteins were determined by Western blotting. Our results revealed that POF mice had prolonged estrous cycles, increased FSH and LH levels, and decreased AMH, E2, and P levels. Treatment with hucMSC-EVs partially counteracted the above changes. D-gal treatment reduced proliferation and raised apoptosis in KGN cells, while hucMSC-EV treatment annulled the changes. D-gal-treated cells exhibited downregulated p-PI3K/PI3K and p-Akt/Akt levels, while hucMSC-EVs activated the PI3K/Akt pathway. LY294002 suppressed the roles of hucMSC-EVs in promoting KGN cell proliferation and lowering apoptosis. Collectively, hucMSC-EVs facilitate proliferation and suppress apoptosis of ovarian granulosa cells by activating the PI3K/Akt pathway, thereby alleviating POF.

Harnessing the Potential of Non-Apoptotic Cell Death Processes in the Treatment of Drug-Resistant Melanoma

Melanoma is a highly malignant skin cancer that is known for its resistance to treatments. In recent years, there has been significant progress in the study of non-apoptotic cell death, such as pyroptosis, ferroptosis, necroptosis, and cuproptosis. This review provides an overview of the mechanisms and signaling pathways involved in non-apoptotic cell death in melanoma. This article explores the interplay between various forms of cell death, including pyroptosis, necroptosis, ferroptosis, and cuproptosis, as well as apoptosis and autophagy. Importantly, we discuss how these non-apoptotic cell deaths could be targeted as a promising therapeutic strategy for the treatment of drug-resistant melanoma. This review provides a comprehensive overview of non-apoptotic processes and gathers recent experimental evidence that will guide future research and eventually the creation of treatment strategies to combat drug resistance in melanoma.

Bioactive fatty acid analog-derived hybrid nanoparticles confer antibody-independent chemo-immunotherapy against carcinoma

Typical chemo-immunotherapy against malignant carcinoma, is characterized by the combined application of chemotherapeutic agents and monoclonal antibodies for immune checkpoint blockade (ICB). Temporary ICB with antibodies would not depress tumor intrinsic PD-L1 expression and potential PD-L1 adaptive upregulation during chemotherapy, thus exerting limited immunotherapy efficacy. Herein, we developed novel polymer-lipid hybrid nanoparticles (2-BP/CPT-PLNs) for inducing PD-L1 degradation by inhibiting palmitoylation with bioactive palmitic acid analog 2-bromopalmitate (2-BP) to replace PD-L1 antibody (αPD-L1) for ICB therapy, thus achieving highly efficient antitumor immune via immunogenic cell death (ICD) induced by potentiated chemotherapy. GSH-responsive and biodegradable polymer-prodrug CPT-ss-PAEEP₁₀ assisted as a cationic helper polymer could help to stabilize 2-BP/CPT-PLNs co-assembled with 2-BP, and facilitate the tumor site-specific delivery and intracellular release of water-insoluble camptothecin (CPT) in vivo. 2-BP/CPT-PLNs would reinforce cytotoxic CD8⁺ T cell-mediated antitumor immune response via promoting intratumoral lymphocytes cells infiltration and activation. 2-BP/CPT-PLNs significantly prevented melanoma progression and prolonged life survival of mice beyond the conventional combination of irinotecan hydrochloride (CPT-11) and αPD-L1. Our work first provided valuable instructions for developing bioactive lipid analogs-derived nanoparticles via lipid metabolism intervention for oncotherapy.

Exosomes: Diagnostic and Therapeutic Implications in Cancer

Exosomes are a subset of extracellular vesicles produced by all cells, and they are present in various body fluids. Exosomes play crucial roles in tumor initiation/progression, immune suppression, immune surveillance, metabolic reprogramming, angiogenesis, and the polarization of macrophages. In this work, we summarize the mechanisms of exosome biogenesis and secretion. Since exosomes may be increased in the cancer cells and body fluids of cancer patients, exosomes and exosomal contents can be used as cancer diagnostic and prognostic markers. Exosomes contain proteins, lipids, and nucleic acids. These exosomal contents can be transferred into recipient cells. Therefore, this work details the roles of exosomes and exosomal contents in intercellular communications. Since exosomes mediate cellular interactions, exosomes can be targeted for developing anticancer therapy. This review summarizes current studies on the effects of exosomal inhibitors on cancer initiation and progression. Since exosomal contents can be transferred, exosomes can be modified to deliver molecular cargo such as anticancer drugs, small interfering RNAs (siRNAs), and micro RNAs (miRNAs). Thus, we also summarize recent advances in developing exosomes as drug delivery platforms. Exosomes display low toxicity, biodegradability, and efficient tissue targeting, which make them reliable delivery vehicles. We discuss the applications and challenges of exosomes as delivery vehicles in tumors, along with the clinical values of exosomes. In this review, we aim to highlight the biogenesis, functions, and diagnostic and therapeutic implications of exosomes in cancer.

In Situ Transformable Nanoplatforms with Supramolecular Cross-Linking Triggered Complementary Function for Enhanced Cancer Photodynamic Therapy

In vivo cross-linking of nanoparticles is widely used to increase accumulation of therapeutic agents at tumor site for enhanced therapy. However, the components in nanoplatforms usually only play for one role and are independent of each other, unable to amplify their biofunctions. Herein, a complementary functioning tumor microenvironment triggered, supramolecular coordination-induced nanoparticle cross-linking strategy is constructed for enhanced photodynamic therapy. Manganese oxide (MnO_x ) and polyhydroxy photosensitizer hypericin (Hyp) are coated and loaded onto lanthanide-doped upconversion nanoparticles (UCNPs) to form transformable UCNP@MnO_x -Hyp. In CT26 mouse colon cancer cells and xenograft tumors, UCNP@MnO_x -Hyp is reduced by glutathione and H₂ O₂ , releasing Mn²⁺ and Hyp for in situ cross-linking to transform to UCNP@Mn²⁺ -Hyp. Compared to the simple photosensitizer-loaded UCNP@PEI-Hyp, the Mn²⁺ -Hyp coordination redshifts absorbance of Hyp and improves the energy transfer efficiency from UCNPs to Hyp (5.6-fold). In turn, the supramolecular coordination-induced UCNPs cross-linking exhibits enhanced luminescence recovery and increased intracellular accumulation of both UCNPs and Hyp, thus enhancing the photodynamic therapy efficacy both at cellular level (2.1-fold) and in vivo, realizing the function amplification of each component after responsive transformation and offering a new avenue for enhanced cancer therapy.

An enzyme-responsive and transformable PD-L1 blocking peptide-photosensitizer conjugate enables efficient photothermal immunotherapy for breast cancer

Mild photothermal therapy combined with immune checkpoint blockade has received increasing attention for the treatment of advanced or metastatic cancers due to its good therapeutic efficacy. However, it remains a challenge to facilely integrate the two therapies and make it potential for clinical translation. This work designed a peptide-photosensitizer conjugate (PPC), which consisted of a PD-L1 antagonist peptide (CVRARTR), an MMP-2 specific cleavable sequence, a self-assembling motif, and the photosensitizer Purpurin 18. The single-component PPC can self-assemble into nanospheres which is suitable for intravenous injection. The PPC nanosphere is cleaved by MMP-2 when it accumulates in tumor sites, thereby initiating the cancer-specific release of the antagonist peptide. Simultaneously, the nanospheres gradually transform into co-assembled nanofibers, which promotes the retention of the remaining parts within the tumor. In vivo studies demonstrated that PPC nanospheres under laser irradiation promote the infiltration of cytotoxic T lymphocytes and maturation of DCs, which sensitize 4T1 tumor cells to immune checkpoint blockade therapy. Therefore, PPC nanospheres inhibit tumor growth efficiently both in situ and distally and blocked the formation of lung metastases. The present study provides a simple and efficient integrated strategy for breast cancer photoimmunotherapy.

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A peptide-photosensitizer conjugate (PPC) with self-assembled ability.

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Self-assembled PPC realized enzyme-responsive PD-L1 blocking peptide release.

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Shape transformation from nanospheres to co-assembled nanofibers.

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Efficient integrated strategy for breast cancer photoimmunotherapy.

From Exosome Biogenesis to Absorption: Key Takeaways for Cancer Research

Exosomes are mediators of intercellular communication in normal physiology and diseases. While many studies have emerged on the function of exosomal cargoes, questions remain regarding the origin of these exosomes. The packaging and secretion of exosomes in different contexts modify exosomal composition, which may in turn impact delivery, uptake and cargo function in recipient cells. A mechanistic understanding of exosome biology is therefore crucial to investigating exosomal function in complex biological systems and to the development of novel therapeutic approaches. Here, we outline the steps in exosome biogenesis, including endosome formation, MVB formation, cargo sorting and extracellular release, as well as exosome absorption, including targeting, interaction with recipient cells and the fate of internalized exosomes. In addition to providing a framework of exosome dynamics, we summarize current evidence on major pathways and regulatory mechanisms. We also highlight the various mechanisms observed in cancer and point out directions to improve study design in exosome biology. Further research is needed to illuminate the relationship between exosome biogenesis and function, which will aid the development of translational applications.

Heterostructural Nanoadjuvant CuSe/CoSe2 for Potentiating Ferroptosis and Photoimmunotherapy through Intratumoral Blocked Lactate Efflux

The desirable curative effect in clinical immunotherapy has been challenging due to the immunosuppressive tumor microenvironment (TME) with high lactic acid (LA) metabolism in solid tumors. Although targeting metabolic reprogramming of tumor cells can restore the survival and function of immune cells in the TME, it is also plagued by insufficient immunogenicity. Herein, an activatable immunomodulatory nanoadjuvant CuSe/CoSe₂@syrosingopine (CSC@Syro) is constructed for simultaneously relieving immunosuppressive TME and boosting tumor immune response. Specifically, CuSe/CoSe₂ (CSC) exhibits TME-activated glutathione (GSH) depletion and hydroxyl radical (^•OH) generation for potential ferroptosis. Meanwhile, the remarkable photothermal conversion efficiency and elevated photocatalytic ROS level both promote CSC heterostructures to induce robust immunogenic cell death (ICD). Besides, the loaded syrosingopine inhibitor achieves LA metabolism blockade in cancer cells by downregulating the expression of monocarboxylate transporter 4 (MCT4), which could sensitize ferroptosis by intracellular milieu acidification and neutralize the acidic TME to alleviate immunosuppression. Hence, advanced metabolic modulation confers the potentiated immune infiltration of ICD-stimulated T lymphocytes and further reinforces antitumor therapy. In brief, CSC@Syro-mediated synergistic therapy could elicit potent immunogenicity and suppress tumor proliferation and metastasis effectually by integrating the tumor metabolic regulation and ferroptosis with immunotherapy.

Bioactive inorganic nanomaterials for cancer theranostics

Bioactive materials are a special class of biomaterials that can react in vivo to induce a biological response or regulate biological functions, thus achieving a better curative effect than traditional inert biomaterials. For cancer theranostics, compared with organic or polymer nanomaterials, inorganic nanomaterials possess unique physical and chemical properties, have stronger mechanical stability on the basis of maintaining certain bioactivity, and are easy to be compounded with various carriers (polymer carriers, biological carriers, etc.), so as to achieve specific antitumor efficacy. After entering the nanoscale, due to the nano-size effect, high specific surface area and special nanostructures, inorganic nanomaterials exhibit unique biological effects, which significantly influence the interaction with biological organisms. Therefore, the research and applications of bioactive inorganic nanomaterials in cancer theranostics have attracted wide attention. In this review, we mainly summarize the recent progress of bioactive inorganic nanomaterials in cancer theranostics, and also introduce the definition, synthesis and modification strategies of bioactive inorganic nanomaterials. Thereafter, the applications of bioactive inorganic nanomaterials in tumor imaging and antitumor therapy, including tumor microenvironment (TME) regulation, catalytic therapy, gas therapy, regulatory cell death and immunotherapy, are discussed. Finally, the biosafety and challenges of bioactive inorganic nanomaterials are also mentioned, and their future development opportunities are prospected. This review highlights the bioapplication of bioactive inorganic nanomaterials.

Metal-Phenolic Network-Facilitated "Foe-to-Friend" Conversion of Melittin for Cancer Immunotherapy with Boosted Abscopal Effect

As a naturally occurring cytolytic peptide, melittin (Mel) has strong cytolytic activity and is a potent therapeutic peptide for cancer therapy. However, the serious hemolytic activity of Mel largely impedes its clinical applications. In this work, based on the strong interactions between proteins/peptides and polyphenols, we develop a tannic acid-Fe³⁺ metal-phenolic network (MPN)-based strategy that can convert Mel from foe to friend via shielding its positive charges and reducing its hemolytic activity. Besides, an immune adjuvant resiquimod (R848) is also introduced for immunostimulation, affording the final Mel- and R848-coloaded nanodrug. The Mel-caused membrane disruption can induce immunogenic cell death for immunostimulation, R848 can act as an immune adjuvant to further facilitate the immunostimulatory effect, and the tannic acid-Fe³⁺ MPN-mediated Fenton reaction can produce reactive oxygen species for cancer treatment. Further experiments reveal that the nanodrug can effectively cause immunogenic cell death of tumor cells and arouse robust intratumoral and systemic antitumor immunostimulation. In the bilateral tumor-bearing mouse models, the nanodrug considerably destroys the primary tumor and also boosts the abscopal effect to ablate the distant tumor. Collectively, the MPN-facilitated "foe-to-friend" strategy may promote the practical applications of Mel and foster the development of cancer immunotherapeutics.

Extracellular Vesicles in Cancer Drug Resistance: Implications on Melanoma Therapy

Extracellular vesicles (EVs) are involved in the pathogenesis of neoplastic diseases. Their role in mediating drug resistance has been widely described in several types of cancers, including melanoma. EVs can mediate drug resistance through several different mechanisms, such as drug-sequestration, transfer of pro-survival proteins and RNA, induction of cancer stem cell-like features and interaction with cells of the tumor microenvironment and immune-system. Melanoma is a highly immunogenic tumor originating from the malignant transformation of melanocytes. Several therapeutic strategies currently used in the treatment of melanoma and the combination of BRAF and MEK-inhibitors, as well as immune check-point inhibitors (ICI), have consistently improved the overall survival time of melanoma patients. However, the development of resistance is one of the biggest problems leading to a poor clinical outcome, and EVs can contribute to this. EVs isolated from melanoma cells can contain "sequestered" chemotherapeutic drugs in order to eliminate them, or bioactive molecules (such as miRNA or proteins) that have been proven to play a crucial role in the transmission of resistance to sensitive neoplastic cells. This leads to the hypothesis that EVs could be considered as resistance-mediators in sensitive melanoma cells. These findings are a pivotal starting point for further investigations to better understand EVs' role in drug resistance mechanisms and how to target them. The purpose of this review is to summarize knowledge about EVs in order to develop a deeper understanding of their underlying mechanisms. This could lead to the development of new therapeutic strategies able to bypass EV-mediated drug-resistance in melanoma, such as by the use of combination therapy, including EV release inhibitors.

HRS Regulates Small Extracellular Vesicle PD-L1 Secretion and Is Associated with Anti-PD-1 Treatment Efficacy

PD-L1 localized to immunosuppressive small extracellular vesicles (sEV PD-L1) contributes to tumor progression and is associated with resistance to immune-checkpoint blockade (ICB) therapy. Here, by establishing a screening strategy with a combination of tissue microarray (TMA), IHC staining, and measurement of circulating sEV PD-L1, we found that the endosomal sorting complex required for transport (ESCRT) member protein hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) was the key regulator of circulating sEV PD-L1 in head and neck squamous cell carcinoma (HNSCC) patients. Increased HRS expression was found in tumor tissues and positively correlated with elevated circulating sEV PD-L1 in patients with HNSCC. The expression of HRS was also negatively correlated to the infiltration of CD8+ T cells. Knockdown of HRS markedly reduced PD-L1 expression in HNSCC cell-derived sEVs, and these sEVs from HRS knockdown cells showed decreased immunosuppressive effects on CD8+ T cells. Knockout of HRS inhibited tumor growth in immunocompetent mice together with PD-1 blockade. Moreover, a higher HRS expression was associated with a lower response rate to anti-PD-1 therapy in patients with HNSCC. In summary, our study reveals HRS, the core component of ESCRT-0, regulates sEV PD-L1 secretion, and is associated with the response to ICB therapy in patients with HNSCC, suggesting HRS is a promising target to improve cancer immunotherapy.

Circulating Exosomal PD-L1 at Initial Diagnosis Predicts Outcome and Survival of Patients with Osteosarcoma

PURPOSE

It is difficult to predict prognosis of patients with osteosarcoma at initial diagnosis due to lack of efficient prognostic parameters. We evaluated the relationship between level of circulating serum exosomal PD-L1 (Sr-exosomal PD-L1) at initial diagnosis and oncologic outcome during the follow-up.

EXPERIMENTAL DESIGN

Sixty-seven patients with newly diagnosed osteosarcoma were prospectively recruited. Fasting blood was collected and exosome isolation was performed using ultracentrifugation method. Evaluation of Sr-exosomal PD-L1 was performed respectively by immunogold labeling and ELISA method. Correlation between level of Sr-exosomal PD-L1 at initial diagnosis and clinical risk factors was assessed.

RESULTS

Mean follow-up was 46.7 months. Two-year and 5-year overall survival (OS) rates were respectively 96.9% and 62.5%. Two-year and 5-year disease-free survival (DFS) rates were respectively 85.0% and 31.4%. Results revealed a significantly positive association between high PD-L1 cargo of circulating exosomes and clinicopathologic disease markers such as pulmonary metastasis, multiple metastasis, and death. Patients who died of disease at final follow-up had higher level of Sr-exosomal PD-L1 at initial diagnosis, which compared with patients who were still alive at last follow-up. Patients in group of ≥14.23 pg/mL Sr-exosomal PD-L1 at initial diagnosis had inferior DFS compared with patients in group of <14.23 pg/mL at initial diagnosis. Patients in group of ≥25.96 pg/mL at initial diagnosis had poor OS compared with patients in group of <25.96 pg/mL at initial diagnosis.

CONCLUSIONS

Use of liquid biopsy of circulating exosomal PD-L1 at initial diagnosis provides a robust means of predicting prognosis for patients with a newly diagnosed osteosarcoma.

Critical roles of linker length in determining the chemical and self-assembly stability of SN38 homodimeric nanoprodrugs

Homodimeric prodrug nanoassemblies (HDPNs) have been widely studied for efficient cancer therapy by virtue of their ultra-high drug loading and distinct nanostructure. However, the development of SN38 HDPNs is still a great challenge due to the rigid planar aromatic ring structure. Improving the structural flexibility of homodimeric prodrugs by increasing the linker length may be a potential strategy for constructing SN38 HDPNs. Herein, three SN38 homodimeric prodrugs with different linker lengths were synthesized. The number of carbon atoms from the disulfide bond to the adjacent ester bond is 1 (denoted as α-SN38-SS-SN38), 2 (β-SN38-SS-SN38), and 3 (γ-SN38-SS-SN38), respectively. Interestingly, we found that α-SN38-SS-SN38 exhibited extremely low yield and poor chemical stability. Additionally, β-SN38-SS-SN38 demonstrated suitable chemical stability but poor self-assembly stability. In comparison, γ-SN38-SS-SN38 possessed good chemical and self-assembly stability, thereby improving the tumor accumulation and antitumor efficacy of SN38. We developed the SN38 HDPNs for the first time and illustrated the underlying molecular mechanism of increasing the linker length to enhance the chemical and self-assembly stability of homodimeric prodrugs. These findings would provide new insights for the rational design of HDPNs with superior performance.

Mechanisms of function and clinical potential of exosomes in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) remains one of the most lethal and widespread malignancies in China. Exosomes, a subset of tiny extracellular vesicles manufactured by all cells and present in all body fluids, contribute to intercellular communication and have become a focus of the search for new therapeutic strategies for cancer. A number of global analyses of exosome-mediated functions and regulatory mechanism in malignant diseases have recently been reported. There is extensive evidence that exosomes can be used as diagnostic and prognostic markers for cancer. However, our understanding of their clinical value and mechanisms of action in ESCC is still limited and has not been systematically reviewed. Here, we review current research specifically focused on the functions and mechanisms of action of ESCC tumor-derived exosomes and non-ESCC-derived exosomes in ESCC progression and describe opportunities and challenges in the clinical translation of exosomes.

Research advances in the understanding of how exosomes regulate ferroptosis in cancer

Exosomes are extracellular vesicles that can release different bioactive substances to affect tumor cells and cell death pathways. As an important mediator of cell communication, exosomes participate in the occurrence and development of a variety of diseases. Ferroptosis, one of the newly defined forms of regulated cell death, is characterized by massive accumulation of iron ions and lipid peroxidation. An increasing number of studies have shown that ferroptosis plays an important role in malignant tumors. Moreover, exosomes have been recognized for their potential in cancer therapy based on ferroptosis. To further describe how could exosomes regulate ferroptosis in cancer and provide better understanding of the mechanisms involved, this paper reviews the definition as well as the underlying molecular mechanisms of ferroptosis, including iron metabolism, amino acid metabolism, lipid metabolism and so on. Then, we illustrated how could exosomes regulate the ferroptosis pathway and suggested their promising potential as a novel tumor therapy for cancer patients. Finally, we described the perspectives of ferroptosis by exosomes in tumor treatment. Therefore, exosomes have the potential to regulate ferroptosis in clinical cancer treatment.

Implications of Crosstalk between Exosome-Mediated Ferroptosis and Diseases for Pathogenesis and Treatment

Ferroptosis is a type of iron-dependent cell death caused by ferrous iron overload, reactive oxygen species generation through the Fenton reaction, and lipid peroxidation, leading to antioxidative system dysfunction and, ultimately, cell membrane damage. The functional role of ferroptosis in human physiology and pathology is considered a cause or consequence of diseases. Circulating exosomes mediate intercellular communication and organ crosstalk. They not only transport functional proteins and nucleic acids derived from parental cells but also serve as vehicles for the targeted delivery of exogenous cargo. Exosomes regulate ferroptosis by delivering the biological material to the recipient cell, affecting ferroptosis-related proteins, or transporting ferritin-bound iron out of the cell. This review discusses pathogenesis mediated by endogenous exosomes and the therapeutic potential of exogenous exosomes for ferroptosis-related diseases. In addition, this review explores the role of exosome-mediated ferroptosis in ferroptosis-related diseases with an emphasis on strategies for engineering exosomes for ferroptosis therapy.

Iron-Containing Protein-Mimic Supramolecular Iron Delivery Systems for Ferroptosis Tumor Therapy

Ferroptosis provides an innovative theoretical basis and method for tumor therapy but is limited by the low efficiency of conventional iron delivery systems. Herein, an efficient supramolecular iron delivery system (SIDS) is demonstrated upon the hydrolysis of FeCl₃, condensation of amino acids, and self-assembly of iron-containing components. The as-assembled SIDS possesses a shuttle-like core/shell structure with β-FeOOH as the core and Fe³⁺/polyamino acid coordinated networks as shells. The iron content of SIDS is up to 42 wt %, which is greatly higher than that of ferritin. The iron-containing protein-mimic structure and shuttle-like morphology of SIDS facilitate tumor accumulation and cell internalization. Once exposed to the tumor microenvironment with overexpressed glutathione (GSH), the SIDS will disassemble, accompanied by the depletion of GSH and the release of Fe²⁺, leading to dual amplified ferroptosis. Primary studies indicate that SIDS exhibits outstanding antitumor efficacy on bladder cancer.

Extracellular Vesicles Are Important Mediators That Regulate Tumor Lymph Node Metastasis via the Immune System

Extracellular vesicles (EVs) are particles with a lipid bilayer structure, and they are secreted by various cells in the body. EVs interact with and modulate the biological functions of recipient cells by transporting their cargoes, such as nucleic acids and proteins. EVs influence various biological phenomena, including disease progression. They also participate in tumor progression by stimulating a variety of signaling pathways and regulating immune system activation. EVs induce immune tolerance by suppressing CD8⁺ T-cell activation or polarizing macrophages toward the M2 phenotype, which results in tumor cell proliferation, migration, invasion, and metastasis. Moreover, immune checkpoint molecules are also expressed on the surface of EVs that are secreted by tumors that express these molecules, allowing tumor cells to not only evade immune cell attack but also acquire resistance to immune checkpoint inhibitors. During tumor metastasis, EVs contribute to microenvironmental changes in distant organs before metastatic lesions appear; thus, EVs establish a premetastatic niche. In particular, lymph nodes are adjacent organs that are connected to tumor lesions via lymph vessels, so that tumor cells metastasize to draining lymph nodes at first, such as sentinel lymph nodes. When EVs influence the microenvironment of lymph nodes, which are secondary lymphoid tissues, the immune response against tumor cells is weakened; subsequently, tumor cells spread throughout the body. In this review, we will discuss the association between EVs and tumor progression via the immune system as well as the clinical application of EVs as biomarkers and therapeutic agents.

Boosting ferroptosis and microtubule inhibition for antitumor therapy via a carrier-free supermolecule nanoreactor

Traditional microtubule inhibitors fail to significantly enhance the effect of colorectal cancer; hence, new and efficient strategies are necessary. In this study, a supramolecular nanoreactor (DOC@TA-Fe³⁺) based on tannic acid (TA), iron ion (Fe³⁺), and docetaxel (DOC) with microtubule inhibition, reactive oxygen species (ROS) generation, and glutathione peroxidase 4 (GPX4) inhibition, is prepared for ferroptosis/apoptosis treatment. After internalization by CT26 cells, the DOC@TA-Fe³⁺ nanoreactor escapes from the lysosomes to release payloads. The subsequent Fe³⁺/Fe²⁺ conversion mediated by TA reducibility can trigger the Fenton reaction to enhance the ROS concentration. Additionally, Fe³⁺ can consume glutathione to repress the activity of GPX4 to induce ferroptosis. Meanwhile, the released DOC controls microtubule dynamics to activate the apoptosis pathway. The superior in vivo antitumor efficacy of DOC@TA-Fe³⁺ nanoreactor in terms of tumor growth inhibition and improved survival is verified in CT26 tumor-bearing mouse model. Therefore, the nanoreactor can act as an effective apoptosis and ferroptosis inducer for application in colorectal cancer therapy.

Extracellular vesicles: A dive into their role in the tumor microenvironment and cancer progression

Extracellular vesicles (EVs) encompass a diverse set of membrane-derived particles released from cells and are found in numerous biological matrices and the extracellular space. Specific classes of EVs include apoptotic bodies, exosomes, and microvesicles, which vary in their size, origin, membrane protein expression, and interior cargo. EVs provide a mechanism for shuttling cargo between cells, which can influence cell physiology by transporting proteins, DNA, and RNA. EVs are an abundant component of the tumor microenvironment (TME) and are proposed to drive tumor growth and progression by communicating between fibroblasts, macrophages, and tumor cells in the TME. The cargo, source, and type of EV influences the pro- or anti-tumoral role of these molecules. Therefore, robust EV isolation and characterization techniques are required to ensure accurate elucidation of their association with disease. Here, we summarize different EV subclasses, methods for EV isolation and characterization, and a selection of current clinical trials studying EVs. We also review key studies exploring the role and impact of EVs in the TME, including how EVs mediate intercellular communication, drive cancer progression, and remodel the TME.

A nanoformulation for immunosuppression reversal and broad-spectrum self-amplifying antitumor ferroptosis-immunotherapy

The efficacy of immunotherapy combined with other therapeutic modalities in the management of cancer has been extensively studied. However, no effective strategy to improve the antitumor effects of immunotherapy at the tumor site has been developed. In this study, we describe a nanoformulation (CP) that integrates ferroptosis-inducing cannabinoid nanoparticles with immunostimulatory Poly(I:C) to enhance antitumor immune responses by activating ferroptosis-immunotherapy pathways. The results indicated that CP nanoformulation effectively induced ferroptosis, cellular immunogenic death, and anti-tumor immune responses which initiate T cell responses leading to the inhibition of established tumors. In addition, CP nanoformulations reversed the tumor immunosuppressive microenvironment and promoted tumor ferroptosis. These results indicated that the self-amplifying nanoformulation may be an effective strategy for broad-spectrum cancer immunotherapy.

Dissecting order amidst chaos of programmed cell deaths: construction of a diagnostic model for KIRC using transcriptomic information in blood-derived exosomes and single-cell multi-omics data in tumor microenvironment

Background

Kidney renal clear cell carcinoma (KIRC) is the most frequently diagnosed subtype of renal cell carcinoma (RCC); however, the pathogenesis and diagnostic approaches for KIRC remain elusive. Using single-cell transcriptomic information of KIRC, we constructed a diagnostic model depicting the landscape of programmed cell death (PCD)-associated genes, namely cell death-related genes (CDRGs).

Methods

In this study, six CDRG categories, including apoptosis, necroptosis, autophagy, pyroptosis, ferroptosis, and cuproptosis, were collected. RNA sequencing (RNA-seq) data of blood-derived exosomes from the exoRBase database, RNA-seq data of tissues from The Cancer Genome Atlas (TCGA) combined with control samples from the GTEx databases, and single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database were downloaded. Next, we intersected the differentially expressed genes (DEGs) of the KIRC cohort from exoRBase and the TCGA databases with CDRGs and DEGs obtained from single-cell datasets, further screening out the candidate biomarker genes using clinical indicators and machine learning methods and thus constructing a diagnostic model for KIRC. Finally, we investigated the underlying mechanisms of key genes and their roles in the tumor microenvironment using scRNA-seq, single-cell assays for transposase-accessible chromatin sequencing (scATAC-seq), and the spatial transcriptomics sequencing (stRNA-seq) data of KIRC provided by the GEO database.

Result

We obtained 1,428 samples and 216,155 single cells. After the rational screening, we constructed a 13-gene diagnostic model for KIRC, which had high diagnostic efficacy in the exoRBase KIRC cohort (training set: AUC = 1; testing set: AUC = 0.965) and TCGA KIRC cohort (training set: AUC = 1; testing set: AUC = 0.982), with an additional validation cohort from GEO databases presenting an AUC value of 0.914. The results of a subsequent analysis revealed a specific tumor epithelial cell of TRIB3^high subset. Moreover, the results of a mechanical analysis showed the relatively elevated chromatin accessibility of TRIB3 in tumor epithelial cells in the scATAC data, while stRNA-seq verified that TRIB3 was predominantly expressed in cancer tissues.

Conclusions

The 13-gene diagnostic model yielded high accuracy in KIRC screening, and TRIB3^high tumor epithelial cells could be a promising therapeutic target for KIRC.

Monophosphoryl lipid A ameliorates radiation-induced lung injury by promoting the polarization of macrophages to the M1 phenotype

Background

Radiation-induced lung injury (RILI) often occurs during clinical chest radiotherapy and acute irradiation from accidental nuclear leakage. This study explored the role of monophosphoryl lipid A (MPLA) in RILI.

Materials and Methods

The entire thoracic cavity of C57BL/6N mice was irradiated at 20 Gy with or without pre-intragastric administration of MPLA. HE staining, Masson trichrome staining, and TUNEL assay were used to assess lung tissue injury after treatment. The effect of irradiation on the proliferation of MLE-12 cells was analyzed using the Clonogenic assay. The effect of MPLA on the apoptosis of MLE-12 cells was analyzed using flow cytometry. Expression of γ-H2AX and epithelial-mesenchymal transition (EMT) markers in MLE-12 cells was detected by immunofluorescence and Western blot, respectively.

Results

MPLA attenuated early pneumonitis and late pulmonary fibrosis after thoracic irradiation and reversed radiation-induced EMT in C57 mice. MPLA further promoted proliferation and inhibited apoptosis of irradiated MLE-12 cells in vitro. Mechanistically, the radioprotective effect of MPLA was mediated by exosomes secreted by stimulated macrophages. Macrophage-derived exosomes modulated DNA damage in MLE-12 cells after irradiation. MPLA promoted the polarization of RAW 264.7 cells to the M1 phenotype. The exosomes secreted by M1 macrophages suppressed EMT in MLE-12 cells after irradiation.

Conclusion

MPLA is a novel treatment strategy for RILI. Exosomes derived from macrophages are key to the radioprotective role of MPLA in RILI.

A novel classification based on non-apoptosis cell death predicts clinical outcomes and immunotherapy response of clear renal cell carcinoma

BACKGROUND

Non-apoptosis cell death could be a secondary consequence of the immune response, which profoundly influences tumor microenvironment (TME), escaping from chemotherapy/immunotherapy-induced apoptosis resistance effects. Whereas, systemic analysis of non-apoptosis regulated cell death associated with TME and clinical outcomes remains unveiled.

METHODS

Our kidney clear carcinoma (KIRC) samples from The Cancer Genome Atlas (TCGA) were stratified into three clusters based on the activity of autophagic cell death, ferroptosis, pyroptosis and necroptosis. Clinical prognosis, TME landscape, biological functions and somatic mutation frequency were compared among the clusters. Additionally, to identify a gene signature highly correlated with clinical prognosis, a risk score model was constructed, and the clinical prognosis, immune infiltration, somatic mutation and biological pathways of risk score subgroups were investigated.

RESULTS

Our non-apoptosis cell death clusters are robustly predictive of immunotherapy responses. Patients in Cluster B are the most sensitive to immune checkpoint blockades-depended immunotherapy. Our risk score model was also verified as a promising biomarker for clinical prognosis and immunotherapy efficiency. Where, the High-risk score group was more sensitive to immunotherapy.

CONCLUSIONS

The novel non-apoptosis cell death-based classification and risk score model could predict the outcome of immunotherapy, and highly associate with immune infiltration. These findings may provide a novel strategy to aid in identificatin of biomarkers and selecting personalized therapeutic strategies.

Engineering metal‐phenolic networks for enhancing cancer therapy by tumor microenvironment modulation

The complicated tumor microenvironment (TME) is featured by low pH values, high redox status, and hypoxia, which greatly supports the genesis, development, and metastasis of tumors, leading to drug resistance and clinical failure. Moreover, a lot of immunosuppressive cells infiltrate in such TME, resulting in depressing immunotherapy. Therefore, the development of TME-responsive nanoplatforms has shown great significance in enhancing cancer therapeutics. Metal-phenolic networks (MPNs)-based nanosystems, which self-assemble via coordination of phenolic materials and metal ions, have emerged as excellent TME theranostic nanoplatforms. MPNs have unique properties including fast preparation, tunable morphologies, pH response, and biocompatibility. Besides, functionalization and surface modification can endow MPNs with specific functions for application requirements. Here, the representative engineering strategies of various polyphenols are first introduced, followed by the introduction of the engineering mechanisms of polyphenolic nanosystems, fabrication, and distinct properties of MPNs. Then, their advances in TME modulation are highlighted, such as antiangiogenesis, hypoxia relief, combination therapy sensitization, and immunosuppressive TME reversion. Finally, we will discuss the challenges and future perspectives of MPNs-based nanosystems for enhancing cancer therapy. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Engineered nanomedicines block the PD-1/PD-L1 axis for potentiated cancer immunotherapy

Immunotherapy, in particular immune checkpoint blockade (ICB) therapy targeting the programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) axis, has remarkably revolutionized cancer treatment in the clinic. Anti-PD-1/PD-L1 therapy is designed to restore the antitumor response of cytotoxic T cells (CTLs) by blocking the interaction between PD-L1 on tumour cells and PD-1 on CTLs. Nevertheless, current anti-PD-1/PD-L1 therapy suffers from poor therapeutic outcomes in a large variety of solid tumours due to insufficient tumour specificity, severe cytotoxic effects, and the occurrence of immune resistance. In recent years, nanosized drug delivery systems (NDDSs), endowed with highly efficient tumour targeting and versatility for combination therapy, have paved a new avenue for cancer immunotherapy. In this review article, we summarized the recent advances in NDDSs for anti-PD-1/PD-L1 therapy. We then discussed the challenges and further provided perspectives to promote the clinical application of NDDS-based anti-PD-1/PD-L1 therapy.

Ferroptosis, necroptosis, and pyroptosis in the tumor microenvironment: Perspectives for immunotherapy of SCLC

Small cell lung cancer (SCLC) is an aggressive form of lung cancer characterized by dismal prognosis. Although SCLC may initially respond well to platinum-based chemotherapy, it ultimately relapses and is almost universally resistant to this treatment. Immune checkpoint inhibitors (ICIs) have been approved as the first- and third-line therapeutic regimens for extensive-stage or relapsed SCLC, respectively. Despite this, only a minority of patients with SCLC respond to ICIs partly due to a lack of tumor-infiltrating lymphocytes (TILs). Transforming the immune "cold" tumors into "hot" tumors that are more likely to respond to ICIs is the main challenge for SCLC therapy. Ferroptosis, necroptosis, and pyroptosis represent the newly discovered immunogenic cell death (ICD) forms. Promoting ICD may alter the tumor microenvironment (TME) and the influx of TILs, and combination of their inducers and ICIs plays a synergistical role in enhancing antitumor effects. Nevertheless, the combination of the above two modalities has not been systematically discussed in SCLC therapy. In the present review, we summarize the roles of distinct ICD mechanisms on antitumor immunity and recent advances of ferroptosis-, necroptosis- and pyroptosis-inducing agents, and present perspectives on these cell death mechanisms in immunotherapy of SCLC.