Exosomal circ50547 as a potential marker and promotor of gastric cancer progression via miR-217/HNF1B axis.

BACKGROUND: Exosomes, one of small extracellular vesicles, play a vital role in cell to cell communication and contribute to the advancement of tumors through their cargo molecules. Exosomal circRNAs have emerged as significant players in various types of tumors. Thus, this study aimed to investigate how exosomal circRNAs are involved in the diagnosis and progression of gastric cancer (GC). METHODS: Serum exosomes were characterized using transmission electron microscopy, nanoparticle tracking analysis and Western blot. CCK-8, colony formation and transwell assays were conducted to study the function of hsa_circ_0050547 (named as circ50547). qRT-PCR was used to quantify the expression of circ50547 in GC tissues and serum exosomes. Fluorescence in situ hybridization was applied to detect the cellular distribution of circ50547. Stemness and drug-resistance were detected by sphere formation, WB, flow cytometry and half-maximal inhibitory concentration analyses. Bioinformatic analyses, luciferase experiments, qRT-PCR and WB were used to investigate molecular mechanisms. RESULTS: We discovered for the first time a new type of GC-derived exosomal circRNA, circ50547. We found that circ50547 is highly expressed in both GC tissues and serum exosomes. Interestingly, we observed that the diagnostic value of exosomal circ50547 is superior to that of serum circ50547. Circ50547 overexpression enhanced the proliferation, migration, invasion, stemness and drug resistance of GC cells, while knockdown of circ50547 showed the opposite effect. Mechanistically, circ50547 acted as a sponge for miR-217 to regulate the expression of HNF1B, which promoted gastric cancer progression. CONCLUSION: Exosomal circ50547 may be a promising marker for the diagnosis and prognosis prediction of GC. These findings suggest that it plays an oncogenic role through miR-217/HNF1B signaling pathway in GC.

Arachidonic acid released by PIK3CA mutant tumor cells triggers malignant transformation of colonic epithelium by inducing chromatin remodeling.

Key gene mutations are essential for colorectal cancer (CRC) development; however, how the mutated tumor cells impact the surrounding normal cells to promote tumor progression has not been well defined. Here, we report that PIK3CA mutant tumor cells transmit oncogenic signals and result in malignant transformation of intestinal epithelial cells (IECs) via paracrine exosomal arachidonic acid (AA)-induced H3K4 trimethylation. Mechanistically, PIK3CA mutations sustain SGK3-FBW7-mediated stability of the cPLA2 protein, leading to the synthetic increase in AA, which is transported through exosome and accumulated in IECs. Transferred AA directly binds Menin and strengthens the interactions of Menin and MLL1/2 methyltransferase. Finally, the combination of VTP50469, an inhibitor of the Menin-MLL interaction, and alpelisib synergistically represses PDX tumors harboring PIK3CA mutations. Together, these findings unveil the metabolic link between PIK3CA mutant tumor cells and the IECs, highlighting AA as the potential target for the treatment of patients with CRC harboring PIK3CA mutations.

Erratum: Circular RNA Hsa_circRNA_101996 promotes the development of Gastric Cancer via Upregulating Matrix Metalloproteinases-2/Matrix Metalloproteinases-9 through MicroRNA-143/Ten-eleven translocation-2 Pathway: Erratum.

[This corrects the article DOI: 10.7150/jca.62121.].

Signal mining and risk analysis of Alprazolam adverse events based on the FAERS database.

This study aims to evaluate the safety of Alprazolam by analyzing the FAERS database, provide data analysis for monitoring adverse drug reactions. This research encompasses adverse event (AE) reports related to Alprazolam from the first quarter of 2004 to the second quarter of 2023. Four signal mining and analysis methods were utilized, including Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Empirical Bayesian Geometric Mean (EBGM). Further exploration was conducted regarding patient characteristics and types of AEs. A total of 23,575 AE reports in which Alprazolam was the primary suspect drug were collected, identifying 347 Preferred Term (PT) signals and 27 System Organ Classes (SOCs). The number of AE reports increased annually, especially in 2015, 2018, 2019, and 2020. The main affected groups were females and the age range of 18 to 45. Psychiatric disorders, Nervous system disorders, and Gastrointestinal disorders were the most common the organ system in which the AEs occurred. There is a certain risk of drug abuse and suicide with Alprazolam. Most notably, several AEs not recorded in the Alprazolam leaflet appeared among the top 30 PTs in signal strength, including but not limited to Benzodiazepine drug level abnormal, Acquired amegakaryocytic thrombocytopenia, Cutaneous T-cell dyscrasia, and Coronary No-reflow Phenomenon. For the first time, AEs related to the cardiovascular system and platelet function were unveiled. The severe AE reports that resulted in "hospitalization" and "death" accounted for 30.96% and 21.86%. This study highlights the risks of suicide and misuse of Alprazolam. Other potential severe or fatal AEs, such as those related to the cardiovascular system, platelet function, and others, require further research to determine their precise mechanisms and risk factors.

CircUSP1 as a novel marker promotes gastric cancer progression via stabilizing HuR to upregulate USP1 and Vimentin.

Circular RNAs (circRNAs) play a crucial role in regulating various tumors. However, their biological functions and mechanisms in gastric cancer (GC) have not been well understood. Here, we discovered a stable cytoplasmic circRNA named circUSP1 (hsa_circ_000613) in GC. CircUSP1 upregulation in GC tissues was correlated with tumor size and differentiation. We observed that circUSP1 promoted GC growth and metastasis. Mechanistically, circUSP1 mainly interacted with the RRM1 domain of an RNA-binding protein (RBP) called HuR, stabilizing its protein level by inhibiting ß-TrCP-mediated ubiquitination degradation. The oncogenic properties of HuR mediated promotive effects of circUSP1 in GC progression. Moreover, we identified USP1 and Vimentin as downstream targets of HuR in post-transcriptional regulation, mediating the effects of circUSP1. The parent gene USP1 also enhanced the viability and mobility of GC cells. Additionally, tissue-derived circUSP1 could serve as an independent prognostic factor for GC, while plasma-derived circUSP1 showed promise as a diagnostic biomarker, outperforming conventional markers including serum alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA) and carbohydrate antigen 199 (CA19-9). Our study highlights that circUSP1 promotes GC progression by binding to and stabilizing oncogenic HuR, thereby facilitating the upregulation of USP1 and Vimentin at the post-transcriptional level. These findings suggest that circUSP1 could be a potential therapeutic target and a diagnostic and prognostic biomarker for GC.

Emerging role of extracellular vesicles in diabetic retinopathy.

Diabetic retinopathy (DR), a complex complication of diabetes mellitus (DM), is a leading cause of adult blindness. Hyperglycemia triggers DR, resulting in microvascular damage, glial apoptosis, and neuronal degeneration. Inflammation and oxidative stress play crucial roles during this process. Current clinical treatments for DR primarily target the advanced retinal disorder but offer limited benefits with inevitable side effects. Extracellular vesicles (EVs) exhibit unique morphological features, contents, and biological properties and can be found in cell culture supernatants, various body fluids, and tissues. In DR, EVs with specific cargo composition would induce the reaction of receptor cell once internalized, mediating cellular communication and disease progression. Increasing evidence indicates that monitoring changes in EV quantity and content in DR can aid in disease diagnosis and prognosis. Furthermore, extensive research is investigating the potential of these nanoparticles as effective therapeutic agents in preclinical models of DR. This review explores the current understanding of the pathological effects of EVs in DR development, discusses their potential as biomarkers and therapeutic strategies, and paves the way for further research and therapeutic advancements.

A molecular container providing supramolecular protection against acetylcholine hydrolysis.

Alzheimer's disease (AD) is characterized by cognitive decline, often attributed to the deficiency of acetylcholine, which can undergo hydrolysis by acetylcholinesterase (AChE) within the biological milieu. Here, we report a supramolecular strategy that takes advantage of confinement effects to inhibit such a hydrolysis process, shedding some light on AD therapy. A water-soluble and bowl-shaped molecule, hexacarboxylated tribenzotriquinacene (TBTQ-C6), was employed to shield acetylcholine (G1) from enzymatic degradation through host-guest binding interactions. Our study revealed highly efficient host-guest interactions with a binding ratio of 1 : 3, resulting in a significant reduction in acetylcholine hydrolysis from 91.1% to 7.4% in the presence of AChE under otherwise identical conditions. Furthermore, TBTQ-C6 showed potential for attenuating the degradation of butyrylcholine (G2) by butyrylcholinesterase (BChE). The broader implications of this study extend to the potential use of molecular containers in various biochemical and pharmacological applications, opening new avenues for research in the field of neurodegenerative diseases.

Engineered extracellular vesicle-encapsulated CHIP as novel nanotherapeutics for treatment of renal fibrosis.

Renal interstitial fibrosis (RIF) is a fundamental pathological feature of chronic kidney disease (CKD). However, toxicity and poor renal enrichment of fibrosis inhibitors limit their further applications. In this study, a platform for CKD therapy is developed using superparamagnetic iron oxide nanoparticles (SPION) decorated mesenchymal stem cells derived extracellular vesicles with carboxyl terminus of Hsc70-interacting protein (CHIP) high expression (SPION-EVs) to achieve higher renal-targeting antifibrotic therapeutic effect. SPION-EVs selectively accumulate at the injury renal sites under an external magnetic field. Moreover, SPION-EVs deliver CHIP to induce Smad2/3 degradation in renal tubular cells which alleviates Smad2/3 activation-mediated fibrosis-like changes and collagen deposition. The extracellular vesicle engineering technology provides a potential nanoplatform for RIF therapy through CHIP-mediated Smad2/3 degradation.

A Dual Role of Mesenchymal Stem Cell Derived Small Extracellular Vesicles on TRPC6 Protein and Mitochondria to Promote Diabetic Wound Healing.

Diabetic wounds exhibit delayed and incomplete healing, usually due to vascular and nerve damage. Dysregulation of cellular Ca2+ homeostasis has recently been shown to be closely related to insulin resistance and type 2 diabetes mellitus. However, the involvement of this dysregulation in diabetic wound complications remains unknown. In this study, we found calcium dysregulation in patients with diabetic ulcers via tissue protein profiling. High glucose and glucometabolic toxicant stimulation considerably impaired the function of TRPC6, a pore subunit of transient receptor potential channels mediating Ca2+ influx, and mitochondria, which regulate calcium cycling and metabolism. Furthermore, we found that mesenchymal stem cell (MSC)-derived small extracellular vesicles (MSC-sEVs) could play a dual role in restoring the function of TRPC6 and mitochondria by delivering transcription factor SP2 and deubiquitinating enzyme USP9, respectively. MSC-sEVs could transfer SP2 that activated TRPC6 expression by binding to its specific promoter regions (-1519 to -1725 bp), thus recovering Ca2+ influx and downstream pathways. MSC-sEVs also promoted mitophagy to restore mitochondrial function by transporting USP9 that stabilized the expression of Parkin, a major player in mitophagy, thereby guaranteeing Ca2+ efflux and avoidance of Ca2+ overload. Targeting the regulation of calcium homeostasis provides a perspective for understanding diabetic wound healing, and the corresponding design of MSC-sEVs could be a potential therapeutic strategy.

Exosomal miRNAs from neutrophils act as accurate biomarkers for gastric cancer diagnosis.

BACKGROUND: Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. Sensitive and accurate biomarkers can greatly aid in early diagnosis and favorable prognosis. Neutrophils are the most abundant immune cells in human circulation and play a critical role in tumor progression. Neutrophil-derived exosomes (Neu-Exo) contain abundant bioactive molecules and are critically involved in disease progression. METHODS: We proposed a Dynabeads-based (CD66b antibody-coupled) separation and detection system for Neu-Exo analysis. Dual antibody-assisted fluorescent Dynabeads was established to detect Neu-Exo abundance. MiRNA signature of Neu-Exo was identified by RNA sequencing. QRT-PCR and droplet digital PCR (ddPCR) were used for candidate miRNA detection and the potential of Neu-Exo miRNAs in the diagnosis of gastric cancer was evaluated. RESULTS: Dual antibody-assisted fluorescent Dynabeads obtained a detection limit of 7.8 × 105 particles/mL of Neu-Exo and a recovery rate of 81 % under optimized conditions. ROC curve indicated that the abundance of CD66b+ Neu-Exo could well distinguish GC patients from healthy controls (HC) (AUC > 0.8). Additionally, miR-223-3p was found among the top differentially expressed miRNAs in Neu-Exo and presented superior diagnostic value in gastric cancer. Droplet digital PCR (ddPCR) significantly improved the diagnostic efficiency to differentiate GC patients from HC and benign gastric diseases (BGD) patients (AUC > 0.9). CONCLUSION: The Dynabeads-based separation and detection system, assisted with ddPCR analysis, provides a promising platform to enrich Neu-Exo and analyze miRNA profile for gastric cancer liquid biopsy.

Indoleamine 2, 3-dioxygenase-transfected bone marrow-derived mesenchymal stem cells promote corneal allograft survival by inhibiting T cell proliferation: A rat study.

PURPOSE: Allograft rejection is still the main cause of corneal transplantation failure. Therefore, we investigated the role of indoleamine 2,3-dioxygenase (IDO)-transfected bone marrow-derived mesenchymal stem cells (IDO-BMSCs) in corneal allograft rejection in rats. METHODS: IDO-BMSCs were constructed and co-cultured with CD4+CD24- T cells to detect their effects on the proliferation of CD4+CD25-T cells in vitro. A corneal allograft rat model was used to confirm our in vitro and in vivo observations. Therefore, IDO-BMSCs were injected directly into the recipient's conjunctiva on the day of corneal transplantation and on day 5 after operation. Corneal graft rejection indices, including corneal neovascularization, opacity, and edema, were measured for up to 14 days after transplantation. The recipients' cervical lymph nodes and peripheral blood were collected to test the role of IDO-BMSCs in immune cells using flow cytometry. RESULTS: The lentivirus-mediated IDO gene was successfully transfected into BMSCs, which stably secreted the IDO protein. The proliferation of CD4+CD25-T cells was significantly inhibited after their co-culture with IDO-BMSCs. Subconjunctival injection of IDO-BMSCs into corneal allografts of rats effectively reduced graft neovascularization, promoted allograft survival, and induced immune tolerance. Both CD4+ and CD8+ T cells in the local lymph nodes and peripheral blood, along with CD4+CD25-T cells in the local lymph nodes, were significantly reduced after transplantation. CONCLUSION: Our results suggest that IDO-BMSC treatment enhances the direct immunomodulatory effect of corneal allograft transplants in rats, promoting corneal allograft survival by inhibiting the proliferation of CD4+, CD8+, and CD4+CD25-T cells. Therefore, modification of BMSCs by lentivirus-mediated IDO gene transfection may provide a novel strategy for controlling corneal allograft rejection.

Engineered mesenchymal stem cell-derived small extracellular vesicles for diabetic retinopathy therapy through HIF-1α/EZH2/PGC-1α pathway.

Diabetic retinopathy (DR) is a leading cause of blindness worldwide with limited treatment options. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) hold promise as a cell-free therapy for retinal diseases. In this study, we present evidence that the intravitreal injection of MSC-sEVs improved retinal function and alleviated retinal apoptosis, inflammation, and angiogenesis in both db/db mice and streptozotocin-induced diabetic rats. Mechanistically, hyperglycemia-induced activation of hypoxia-inducible factor-1α (HIF-1α) inhibited the tripartite motif 21 (TRIM21)-mediated ubiquitination and degradation of enhancer of zeste homologue 2 (EZH2), ultimately resulting in the downregulation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) through EZH2-induced methylation modification. The presence of miR-5068 and miR-10228 in MSC-sEVs targeted the HIF-1α/EZH2/PGC-1α pathway. The blockade of miR-5068 and miR-10228 abolished the retinal therapeutic effects of MSC-sEVs. Additionally, we engineered MSC-sEVs with elevated levels of miR-5068 and miR-10228 to enhance retinal repair efficiency. Together, our findings provide novel insights into the mechanism underlying DR progress and highlight the potential of MSC-sEVs, especially engineered MSC-sEVs, as a therapeutic option for DR.

Circular RNA CDR1as Mediated by Human Antigen R (HuR) Promotes Gastric Cancer Growth via miR-299-3p/TGIF1 Axis.

Background: Gastric cancer (GC) remains a common malignancy worldwide with a limited understanding of the disease mechanisms. A novel circular RNA CDR1as has been recently reported to be a crucial regulator of human cancer. However, its biological role and mechanism in the GC growth are still far from clear. Methods: Small interfering RNAs (siRNAs), lentivirus or plasmid vectors were applied for gene manipulation. The CDR1as effects on the GC growth were evaluated in CCK8 and colony formation assays, a flow cytometry analysis and mouse xenograft tumor models. A bioinformatics analysis combined with RNA immunoprecipitation (RIP), RNA pull-down assays, dual-luciferase reporter gene assays, Western blot, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and functional rescue experiments were used to identify the CDR1as target miRNA, the downstream target gene and its interaction with human antigen R (HuR). Results: The CDR1as overexpression promoted the GC growth in vitro and in vivo and reduced the apoptotic rate of GC cells. Its knockdown inhibited the GC cell proliferation and viability and increased the cell apoptotic rate. Proliferation-related proteins PCNA and Cyclin D1 and apoptosis-related proteins Bax, Bcl-2, Caspase-3 and Caspase-9 were regulated. Mechanically, the cytoplasmic CDR1as acted as a miR-299-3p sponge to relieve its suppressive effects on the GC cell growth. Oncogenic TGIF1 was a miR-299-3p downstream target gene that mediated the promotive effects of CDR1as and regulated the PCNA and Bax levels. HuR interacted with CDR1as via the RRM2 domain and positively regulated the CDR1as level and its oncogenic role as well as downstream target TGIF1. Conclusions: CDR1as promotes the GC growth through the HuR/CDR1as/miR-299-3p/TGIF1 axis and could be used as a new therapeutic target for GC.

Visualization of microRNA therapy in cancers delivered by small extracellular vesicles.

MicroRNA (miRNA) delivery by extracellular vesicles (EVs) has recently inspired tremendous developments in cancer treatments. However, hybridization between miRNA and its target mRNA is still difficult to be imaged in vivo to assess the therapeutic effects in time. Herein we design a nano-scale fluorescent "off-on" complex encapsulated by small extracellular vesicles (sEVs) for real-time visualization and evaluation of gene therapy efficiency in human gastric cancer cells and murine xenograft tumor models. The complex is formed by π-π stacking between graphene quantum dots (GQDs) and tumor suppressor miR-193a-3p conjugated fluorescent tag whose signals remain off when binding to GQDs. Loaded into sEVs using tunable sonication techniques, the GQDs/Cy5-miR particles enter the tumor cells and promote miR-193a-3p escape from endosomes. The miR-193a-3p in GQDs/Cy5-miR is unleashed to pair the specific target oncogene cyclin D1 (CCND1), therefore turning on the fluorescence of miRNA tags. We find out that GQDs/Cy5-miR@sEVs can activate the "turn-on" fluorescent signal and exhibit the longest retention time in vivo, which suggests a minimized degradation of miR-193a-3p in dynamic processes of miRNA-mRNA binding. More importantly, GQDs/Cy5-miR@sEVs significantly promote cancer apoptosis in vitro and in vivo via the enhanced cellular uptake. Our study demonstrates that GQDs/Cy5-miR@sEVs represent an efficient and refined theranostic platform for gene therapy in cancers.

Facile production of cellulose nanofibers from raw elephant grass by an aluminum chloride-enhanced acidic deep eutectic solvent.

To develop a greener and more efficient method for producing cellulose nanofibers (CNFs) from raw plants, an AlCl3-enhanced ternary deep eutectic solvent, DES2 (consisting of choline chloride, citric acid, and AlCl3·6H2O in a molar ratio of 1:0.4:0.08), was synthesized. Raw elephant grass (EG) was pretreated with DES2, followed by sodium chlorite (NaClO2) bleaching and ultrasonic disruption to extract high-performance CNFs. The DES2 and NaClO2 treatments effectively removed hemicellulose and lignin, achieving removal rates of 99.23 % and 99.62 %, respectively, while maintaining a cellulose content of 78.3 %. DES2 demonstrated easy recyclability and maintained excellent biomass pretreatment performance even after multiple cycles. Following a brief 30-min intermittent ultrasound treatment, the resulting CNFs demonstrated superior crystallinity, increased carboxyl content, and a narrower width distribution compared to CNFs obtained from AlCl3-free DES1. Optimized conditions at 110 °C yielded CNFs with 85.3 % crystallinity, 0.64 mmol/g carboxyl content, 5.15 nm width distribution, and excellent dispersion in water for at least six months. Additionally, CNFs enhanced the tensile strength of chia seed mucilage (CM) composite films, showing a significant improvement to 26.6 MPa, representing a 231.3 % increase over the control film. This study offers a promising approach for efficiently producing CNFs from raw plants.

HDAC inhibition delays photoreceptor loss in Pde6b mutant mice of retinitis pigmentosa: insights from scRNA-seq and CUT&Tag.

Purpose: This research aimed to ascertain the neuroprotective effect of histone deacetylase (HDAC) inhibition on retinal photoreceptors in Pde6brd1 mice, a model of retinitis pigmentosa (RP). Methods: Single-cell RNA-sequencing (scRNA-seq) explored HDAC and poly (ADP-ribose) polymerase (PARP)-related gene expression in both Pde6b-mutant rd1 and wild-type (WT) mice. The CUT&Tag method was employed to examine the functions of HDAC in rd1 mice. Organotypic retinal explant cultures from WT and rd1 mice were exposed to the HDAC inhibitor SAHA (suberoylanilide hydroxamic acid) postnatally, from day 5 to day 11. The terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) assay was applied to quantify the percentage of photoreceptor loss in the outer nuclear layer (ONL). HDAC activity was confirmed to be inhibited by SAHA through an HDAC activity assay. Moreover, the study evaluated PARP activity, a key driver of the initial response to DNA damage during photoreceptor degeneration, following HDAC inhibition. Results: The scRNA-seq revealed that diverse roles of HDAC and PARP isoforms in photoreceptor cell death. HDAC-related genes appeared to regulate cell death and primary immunodeficiency. Alterations in HDAC activity were consistent with the TUNEL-positive cells in the ONL at different time points. Notably, SAHA significantly postponed photoreceptor loss and decreased HDAC and PARP activity, thereby implicating both in the same degenerative pathway. Conclusions: This study highlights that the interaction between HDAC inhibition and PARP can delay photoreceptor cell death, proposing a promising therapeutic approach for RP.

Exosomal hsa_circ_000200 as a potential biomarker and metastasis enhancer of gastric cancer via miR-4659a/b-3p/HBEGF axis.

BACKGROUND: Exosome, a component of liquid biopsy, loaded protein, DNA, RNA and lipid gradually emerges as biomarker in tumors. However, exosomal circRNAs as biomarker and function mechanism in gastric cancer (GC) are not well understood. METHODS: Differentially expressed circRNAs in GC and healthy people were screened by database. The identification of hsa_circ_000200 was verified by RNase R and sequencing, and the expression of hsa_circ_000200 was evaluated using qRT-PCR. The biological function of hsa_circ_000200 in GC was verified in vitro. Western blot, RIP, RNA fluorescence in situ hybridization, and double luciferase assay were utilized to explore the potential mechanism of hsa_circ_000200. RESULTS: Hsa_circ_000200 up-regulated in GC tissue, serum and serum exosomes. Hsa_circ_000200 in serum exosomes showed better diagnostic ability than that of tissues and serum. Combined with clinicopathological parameters, its level was related to invasion depth, TNM staging, and distal metastasis. Functionally, knockdown of hsa_circ_000200 inhibited GC cells proliferation, migration and invasion in vitro, while its overexpression played the opposite role. Importantly, exosomes with up-regulated hsa_circ_000200 promoted the proliferation and migration of co-cultured GC cells. Mechanistically, hsa_circ_000200 acted as a "ceRNA" for miR-4659a/b-3p to increase HBEGF and TGF-ß/Smad expression, then promoted the development of GC. CONCLUSIONS: Our findings suggest that hsa_circ_000200 promotes the progression of GC through hsa_circ_000200/miR-4659a/b-3p/HBEGF axis and affecting the expression of TGF-ß/Smad. Serum exosomal hsa_circ_000200 may serve as a potential biomarker for GC.

Engineered Exosomes for Drug Delivery in Cancer Therapy: A promising approach and application.

A significant amount of research effort is currently focused on investigating the role of exosomes in various cancers. These tiny vesicles, apart from acting as biomarkers, also play a crucial role in tumor formation and development. Several studies have demonstrated that exosomes can be a drug delivery vehicle for cancer therapy. In this paper, we highlight the key advantages of exosomes as a drug delivery candidate, with a particular focus on their low immunogenicity, natural targeting ability and suitable mechanical properties. Furthermore, we propose that the selection of appropriate exosomes and drug loading methods based on therapeutic goals and product heterogeneity is essential for preparing engineered exosomes. We comprehensively analyzed the superiorities of current drug-loading methods to improve the creation of designed exosomes. Moreover, we systematically review the applications of engineered exosomes in various therapies such as immunotherapy, gene therapy, protein therapy, chemotherapy, indicating that engineered exosomes have the potential to be reliable and, safe drug carriers that can address the unmet needs in cancer clinical practice.

Gastric cancer mesenchymal stem cells via the CXCR2/HK2/PD-L1 pathway mediate immunosuppression.

BACKGROUND: Anti-PD-1 immunotherapy has emerged as an important therapeutic modality in advanced gastric cancer (GC). However, drug resistance frequently develops, limiting its effectiveness. METHODS: The role of gastric cancer mesenchymal stem cells (GCMSCs) in anti-PD-1 resistance was evaluated in vivo in NPGCD34+ or NCGPBMC xenograft mouse model. In addition, we investigated CD8+T cell infiltration and effector function by spectral cytometry and IHC. The effects of GCMSCs conditional medium (GCMSC-CM) on GC cell lines were characterized at the level of the proteome, secretome using western blot, and ELISA assays. RESULTS: We reported that GCMSCs mediated tolerance mechanisms contribute to tumor immunotherapy tolerance. GCMSC-CM attenuated the antitumor activity of PD-1 antibody and inhibited immune response in humanized mouse model. In GC cells under serum deprivation and hypoxia, GCMSC-CM promoted GC cells proliferation via upregulating PD-L1 expression. Mechanistically, GCMSC-derived IL-8 and AKT-mediated phosphorylation facilitated HK2 nuclear localization. Phosphorylated-HK2 promoted PD-L1 transcription by binding to HIF-1α. What is more, GCMSC-CM also induced lactate overproduction in GC cells in vitro and xenograft tumors in vivo, leading to impaired function of CD8+ T cells. Furthermore, CXCR1/2 receptor depletion, CXCR2 receptor antagonist AZD5069 and IL-8 neutralizing antibody application also significantly reversed GCMSCs mediated immunosuppression, restoring the antitumor capacity of PD-1 antibody. CONCLUSIONS: Our findings reveal that blocking GCMSCs-derived IL-8/CXCR2 pathway decreasing PD-L1 expression and lactate production, improving antitumor efficacy of anti-PD-1 immunotherapy, may be of value for the treatment of advanced gastric carcinoma.

Exosomal circRNA: emerging insights into cancer progression and clinical application potential.

Exosomal circRNA serves a novel genetic information molecule, facilitating communication between tumor cells and microenvironmental cells, such as immune cells, fibroblasts, and other components, thereby regulating critical aspects of cancer progression including immune escape, tumor angiogenesis, metabolism, drug resistance, proliferation and metastasis. Interestingly, microenvironment cells have new findings in influencing tumor progression and immune escape mediated by the release of exosomal circRNA. Given the intrinsic stability, abundance, and broad distribution of exosomal circRNAs, they represent excellent diagnostic and prognostic biomarkers for liquid biopsy. Moreover, artificially synthesized circRNAs may open up new possibilities for cancer therapy, potentially bolstered by nanoparticles or plant exosome delivery strategies. In this review, we summarize the functions and underlying mechanisms of tumor cell and non-tumor cell-derived exosomal circRNAs in cancer progression, with a special focus on their roles in tumor immunity and metabolism. Finally, we examine the potential application of exosomal circRNAs as diagnostic biomarkers and therapeutic targets, highlighting their promise for clinical use.