Endoplasmic reticulum-targeted delivery of celastrol and PD-L1 siRNA for reinforcing immunogenic cell death and potentiating cancer immunotherapy

Celastrol enhanced CD8+T cell immunity in melanoma by targeting SHP2 and upregulating MHC-I

BACKGROUND

Celastrol (CEL) has demonstrated promising anti-cancer properties, yet its specific mechanisms against melanoma remain insufficient. This study investigated the CEL's anti-tumor effects and determined its potential mechanisms in the regulation of MHC-I expression in melanoma. In addition, we also tested its efficacy in sensitizing immune checkpoint inhibitors (ICIs) to melanoma.

METHODS

CEL's anti-tumor activity was evaluated in B16F10 melanoma-bearing C57BL/6 mice across five groups (control, CEL 0.5 mg/kg, CEL 1 mg/kg, CEL 2 mg/kg, and ICIs), the tumor volume, histopathology, and body weight were assessed. Mechanistic insights were obtained through network pharmacology and RNA sequencing in B16F10 cells. Differential gene and pathway analysis were validated using qRT-PCR, Western blotting, and flow cytometry. CD8+T cell activation and cytotoxicity were analyzed in co-culture with CEL-pretreated B16F10 cells using flow cytometry and ELISA. CEL's interaction with potential targets was determined by molecular docking, surface plasmon resonance (SPR), and siRNA. The synergistic effect of CEL combined with ICIs was confirmed in B16F10-bearing C57BL/6 mice, and tumor-infiltrating T cells were assessed by flow cytometry across four groups (control, CEL, ICIs, CEL+ICIs).

RESULTS

CEL exhibited a significant anti-tumor effect in B16F10 melanoma-bearing mice. Mechanistically, CEL-pretreated B16F10 cells notably enhanced CD8+T cell activation and promoted IFNγ and TNFα secretion, leading to B16F10 cell death. CEL upregulated MHC-I expression through activation of the JAK/STAT1 pathway in B16F10 cells. The binding assay revealed that CEL interacted with SHP2, with an affinity of 37.93 μM. When SHP2 was silenced in B16F10 cells by siRNA, CEL failed to induce MHC-I upregulation. Moreover, CEL combined with ICIs produced superior antitumor efficacy compared to ICIs alone, which was accompanied by increased CD8+T cell infiltration in melanoma.

CONCLUSION

CEL enhanced CD8+T cell immunity by upregulating MHC-I expression in melanoma cells, these effects were at least partially through targeting SHP2 and activating JAK/STAT1 pathway. CEL might be a novel sensitizer for ICIs in melanoma.

Immunogenic cell death biomarkers for sepsis diagnosis and mechanism via integrated bioinformatics

Immunogenic cell death (ICD) has been implicated in sepsis, a condition with high mortality, through mechanisms involving endoplasmic reticulum stress and other pathophysiological pathways. This study aimed to identify and validate ICD-related biomarkers for sepsis diagnosis and to elucidate their underlying mechanisms. Publicly available datasets (GSE65682, GSE95233 and GSE69528) and 57 ICD-related genes (ICDRGs) were collected for analysis. Candidate genes were selected using differential expression analysis and weighted gene co-expression network analysis (WGCNA). By integrating machine learning models, receiver operating characteristic (ROC) curves, and gene expression analysis, biomarkers for sepsis diagnosis were identified. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were conducted to explore the potential mechanisms by which the biomarkers influence sepsis. Additionally, immune infiltration analysis, subcellular localization, and disease association analysis were carried out. Finally, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to validate the expression of the biomarkers in clinical sepsis blood samples. The biomarkers BCL2, PRF1, CXCR3, and EIF2AK3 demonstrated robust diagnostic potential for sepsis, each exhibiting an area under the curve (AUC) exceeding 0.8 in both the GSE65682 and GSE95233 datasets. These biomarkers were significantly downregulated in sepsis and were predominantly enriched in the ribosome. GSVA identified the top three activated pathways as β-alanine metabolism, citrate cycle/TCA cycle, and glyoxylate and dicarboxylate metabolism, while the most inhibited pathways included glycosphingolipid biosynthesis (lacto and neolacto series), α-linolenic acid metabolism, and linoleic acid metabolism. Immune infiltration analysis revealed reduced infiltration in sepsis, with CD8 + T cells showing the highest positive correlation with activated NK cells and PRF1. Subcellular localization analysis indicated that all four biomarkers were situated on the organelle membrane. Disease association analysis revealed correlations between these biomarkers and conditions such as hypertension and asthma. RT-qPCR analysis confirmed that the expression patterns of the biomarkers were consistent with the dataset findings, reinforcing the reliability and validity of the bioinformatic analyses. This study identified four ICD-related biomarkers (BCL2, PRF1, CXCR3, and EIF2AK3) that may help recognize early signs of sepsis, facilitate monitoring of disease progression, and have significant potential for clinical diagnosis and therapeutic strategies in sepsis.

Advances in cancer immunotherapy: historical perspectives, current developments, and future directions

Cancer immunotherapy, encompassing both experimental and standard-of-care therapies, has emerged as a promising approach to harnessing the immune system for tumor suppression. Experimental strategies, including novel immunotherapies and preclinical models, are actively being explored, while established treatments, such as immune checkpoint inhibitors (ICIs), are widely implemented in clinical settings. This comprehensive review examines the historical evolution, underlying mechanisms, and diverse strategies of cancer immunotherapy, highlighting both its clinical applications and ongoing preclinical advancements. The review delves into the essential components of anticancer immunity, including dendritic cell activation, T cell priming, and immune surveillance, while addressing the challenges posed by immune evasion mechanisms. Key immunotherapeutic strategies, such as cancer vaccines, oncolytic viruses, adoptive cell transfer, and ICIs, are discussed in detail. Additionally, the role of nanotechnology, cytokines, chemokines, and adjuvants in enhancing the precision and efficacy of immunotherapies were explored. Combination therapies, particularly those integrating immunotherapy with radiotherapy or chemotherapy, exhibit synergistic potential but necessitate careful management to reduce side effects. Emerging factors influencing immunotherapy outcomes, including tumor heterogeneity, gut microbiota composition, and genomic and epigenetic modifications, are also examined. Furthermore, the molecular mechanisms underlying immune evasion and therapeutic resistance are analyzed, with a focus on the contributions of noncoding RNAs and epigenetic alterations, along with innovative intervention strategies. This review emphasizes recent preclinical and clinical advancements, with particular attention to biomarker-driven approaches aimed at optimizing patient prognosis. Challenges such as immunotherapy-related toxicity, limited efficacy in solid tumors, and production constraints are highlighted as critical areas for future research. Advancements in personalized therapies and novel delivery systems are proposed as avenues to enhance treatment effectiveness and accessibility. By incorporating insights from multiple disciplines, this review aims to deepen the understanding and application of cancer immunotherapy, ultimately fostering more effective and widely accessible therapeutic solutions.

Recent advances in PD-L1 siRNA nanocarriers for cancer therapy

Tumor immune evasion depends on the programmed death-ligand 1 (PD-L1) mechanism, making it a prominent target in cancer therapy. Small interfering RNA (siRNA) designed to inhibit PD-L1 expression presents an innovative approach for boosting immunity against tumors. However, the therapeutic use of siRNA faces challenges, primarily due to its instability and inefficient cellular delivery. Recent advancements in nanocarrier technologies have shown promise in overcoming these obstacles, improving the delivery and efficacy of PD-L1 siRNA. This review comprehensively explores various nanocarrier systems, including lipid nanoparticles, polymeric carriers, and inorganic nanoparticles, highlighting their design innovations and applications in targeting PD-L1 in diverse cancer models. We discuss the synergistic effects of PD-L1 siRNA delivered via nanocarriers in conjunction with chemotherapy and immunomodulators, showcasing their potential to boost immune responses and reduce tumor growth. Additionally, we address ongoing challenges such as optimizing biodistribution and minimizing off-target effects, which hinder clinical translation. By synthesizing recent research findings, this review aims to illuminate the transformative potential of PD-L1 siRNA nanocarriers in cancer immunotherapy, paving the way for future studies aimed at enhancing therapeutic strategies and improving patient outcomes.

Metal-based immunogenic cell death inducers for cancer immunotherapy

Immunogenic cell death (ICD) has attracted enormous attention over the past decade due to its unique characteristics in cancer cell death and its role in activating innate and adaptive immune responses against tumours. Many efforts have been dedicated to screening, identifying and discovering ICD inducers, resulting in the validation of several based on metal complexes. In this review, we provide a comprehensive summary of current metal-based ICD inducers, their molecular mechanisms for triggering ICD initiation and subsequent protective antitumour immune responses, along with considerations for validating ICD both in vitro and in vivo. We also aim to offer insights into the future development of metal complexes with enhanced ICD-inducing properties and their applications in potentiating antitumour immunity.

Extracellular Vesicle-Based Antitumor Nanomedicines

Extracellular vesicles (EVs) have emerged as promising bioactive carriers for delivering therapeutic agents, including nucleic acids, proteins, and small-molecule drugs, owing to their excellent physicochemical stability and biocompatibility. However, comprehensive reviews on the various types of EV-based nanomedicines for cancer therapy remain scarce. This review explores the potential of EVs as antitumor nanomedicines. Methods for EV extraction, drug loading, and engineering modifications are systematically examined, and the strengths and limitations of these technical approaches are critically assessed. Additionally, key strategies for developing EV-based antitumor therapies are highlighted. Finally, the opportunities and challenges associated with advancing EVs toward clinical translation are discussed. With the integration of multiple disciplines, robust EV-based therapeutic platforms are expected to be manufactured to provide more personalized and effective solutions for oncology patients.

Injectable celastrol-loading emulsion hydrogel for immunotherapy of low-immunogenic cancer

Immunotherapy, exemplified by immune checkpoint blockade (ICB), has been extensively employed in antitumor treatments. Nevertheless, its efficacy in addressing low-immunogenic tumors has not yielded satisfactory results, primarily due to the depletion and inadequate infiltration of effector T cells within the tumor microenvironment (TME). Here, we construct an injectable water-in-oil emulsion hydrogel to load clinically used Celastrol (Gel@Cel), which addresses the limitations of Cel's hydrophobicity. Cel can both inhibit tumor cell proliferation and promote tumor cell apoptosis, while simultaneously inducing immunogenic cell death, through activation of the AKT and MAPK pathways. In a model of clinically refractory hepatocellular carcinoma with malignant ascites, intraperitoneal administration of Gel@Cel significantly inhibits tumor progression and activates antitumor immune effects through lipase-controlled release of Cel, as compared to free Cel. Intriguingly, the Gel@Cel induces the activation of dendritic cells, resulting in the infiltration of cytotoxic T cells in the TME of ascites. Furthermore, the administration of Cel increases the expression of programmed cell death protein ligand-1 (PD-L1) in tumor cells. Moreover, combining the PD-1 antibody (αPD-1) with Gel@Cel further enhances the antitumor effect and amplifies the immune activation. In conclusion, Gel@Cel exhibits promising therapeutic potential in the treatment of low-immunogenic tumors, especially when combined with ICB therapy.

Regulatory function of endoplasmic reticulum stress in colorectal cancer: Mechanism, facts, and perspectives

Colorectal cancer (CRC) is an exceedingly common and profoundly impactful malignancy of the digestive system, posing a grave threat to human health. Endoplasmic reticulum stress (ERS) is an intracellular biological reaction that mobilizes the unfolded protein response (UPR) to tackling dysregulation in protein homeostasis. This process subtly modulates the cell to either restore normal cellular function or steer it towards apoptosis. The high metabolic demands of CRC cells sculpt a rigorous tumor microenvironment (TME), compelling CRC cells to experience ERS. Adaptive responses induced by mild ERS furnish the necessary conditions for the survival of CRC cells, whereas the cell death mechanisms triggered by sustained ERS could be considered a prospective strategy for cancer therapy. Considering the complex regulation of ERS in cancer development, this article offers a comprehensive review of the molecular mechanisms through which ERS influences CRC fate. It provides crucial insights for exploring the role of ERS in the occurrence and progression of CRC, laying a new theoretical foundation for devising precise therapeutic strategies targeting ERS. Furthermore, by synthesizing extensive clinical and preclinical studies, we delve into therapeutic strategies targeting ERS, including the potential of targeting ERS in immunotherapy, the utilization of native compounds, advancements in proteasome inhibitors, and the potential synergies of these strategies with traditional chemotherapy agents and emerging therapeutic approaches.

Nanomedicine in Immunotherapy for Non-Small Cell Lung Cancer: Applications and Perspectives

Non-small cell lung cancer (NSCLC) has a strikingly high incidence rate globally. Although immunotherapy brings a great breakthrough in its clinical treatment of NSCLC, significant challenges still need to be overcome. The development of novel multi-functional nanomedicines in the realm of tumor immunotherapy offers promising opportunities for NSCLC patients, as nanomedicines exhibit significant advantages, including specific targeting of tumor cells, improved drug bioavailability, reduced systemic toxicity, and overcoming of immune resistance. In this review, the core features and current clinical status of strategies for NSCLC immunotherapy including immune checkpoint blockade, antibody-drug conjugates, cell engagers, adoptive cells, and cancer vaccines, are surveyed. Particular emphasis is placed on the recent development of nanomedicines that boost these strategies. Nanomedicine can provide novel perspectives for NSCLC immunotherapy.

A KIF20A-based thermosensitive hydrogel vaccine effectively potentiates immune checkpoint blockade therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly prevalent malignancy with limited treatment efficacy despite advances in immune checkpoint blockade (ICB) therapy. The inherently weak immune responses in HCC necessitate novel strategies to improve anti-tumor immunity and synergize with ICB therapy. Kinesin family member 20A (KIF20A) is a tumor-associated antigen (TAA) overexpressed in HCC, and it could be a promising target for vaccine development. This study confirmed KIF20A as a promising immunogenic antigen through transcriptomic mRNA sequencing analysis in the context of HCC. Therefore, we developed a thermosensitive hydrogel vaccine formulation (K/RLip@Gel) to optimize antigen delivery while enabling sustained in vivo release. The vaccine efficiently elicited robust immune responses by activating DCs and T cells. Moreover, K/RLip@Gel improved the therapeutic efficacy of PD-L1 blockade in subcutaneous and orthotopic cell-derived xenograft (CDX) models, along with immune-humanized patient-derived xenograft (PDX) HCC models, which was evidenced by improved maturation of DCs and elevated infiltration and activation of CD8+ T cells. These findings highlight the potential of KIF20A-based vaccines to synergistically improve ICB therapy outcomes in HCC, providing a promising approach for enhancing anti-tumor immunity and improving clinical outcomes.

Enhanced Gut-to-Liver Oral Drug Delivery via Ligand-Modified Nanoparticles by Attenuating Protein Corona Adsorption

The development of effective oral drug delivery systems for targeted gut-to-liver transport remains a significant challenge due to the multiple biological barriers including the harsh gastrointestinal tract (GIT) environment and the complex protein corona (PC) formation. In this study, we developed ligand-modified nanoparticles (NPs) that enable gut-to-liver drug delivery by crossing the GIT and attenuating PC formation. Specifically, mesoporous silica nanoparticles (MSNs) were functionalized with peptides targeting the neonatal Fc receptor (FcRn), capitalizing on FcRn expression in the small intestine and liver for targeted drug delivery. We showed that MSNs decorated with a small cyclic FcRn binding peptide (MSNs-FcBP) obtained enhanced diffusion in intestinal mucus and superior transportation across the intestine compared to unmodified MSNs and MSNs decorated with a large IgG Fc fragment (MSNs-Fc), which correlated with diminished protein adsorption and weaker interaction with mucin. After entering the blood circulation, reduced serum PC formation by MSNs-FcBP reduces the proteolytic and phagocytic propensity of the reticuloendothelial system, ultimately ameliorating accumulation in hepatocytes. Pharmacokinetic and pharmacodynamic studies in diabetic mice revealed that MSNs-FcBP effectively transported the therapeutic agent exenatide across the intestinal epithelium, leading to a significant hypoglycemic response and improved glucose tolerance. This study underscores the critical role of ligand selection in limiting protein corona formation, thereby significantly enhancing gut-to-liver drug delivery by increasing mucus permeation and minimizing serum-protein interactions. The effective delivery of exenatide in diabetic mice illustrates the potential of this strategy to optimize oral drug bioavailability and therapeutic efficacy.

Circular RNA circWBSCR22 facilitates colorectal cancer metastasis by enhancing CHD4's protein stability

Widespread metastases continue to be a massive challenge for colorectal cancer (CRC) therapy and contribute to the high mortality rate in patients with CRC. Circular RNAs (circRNAs) are a novel group of endogenous RNAs identified as agents modulating tumorigenesis and aggressiveness with tissue heterogeneity. However, the biological functions of circRNAs in CRC metastasis remain largely unknown. Here, we identified that circWBSCR22, a novel circRNA back-spliced from the WBSCR22 pre-mRNA, was significantly elevated in CRC tissue compared with adjacent normal tissue. Further gain- and loss-of-function assays manifested that circWBSCR22 promotes epithelial-mesenchymal transition (EMT) and metastasis in vitro and in vivo, which are mediated by the chromodomain helicase-DNA-binding protein 4 (CHD4) protein. Mechanically, circWBSCR22 binds directly to up-frameshift protein 1 (UPF1), an RNA binding protein recognized for its function in RNA surveillance, and hinders its role in directing CHD4 protein ubiquitination for degradation. Consequently, by stabilizing the CHD4 protein, circWBSCR22 hastens the development and metastasis of CRC. Therefore, our findings first delineate the oncogenic role and mechanism of circWBSCR22 in CRC growth and metastasis and its potential to serve as a therapeutic target for CRC.