Exosomal ACADM sensitizes gemcitabine-resistance through modulating fatty acid metabolism and ferroptosis in pancreatic cancer

HSPB1/KDM1 A facilitates ANXA2 expression via hypomethylated DNA promoter to inhibit ferroptosis and enhance gemcitabine resistance in pancreatic cancer

Chemotherapy resistance contributes to the unsatisfied prognosis in pancreatic cancer (PC) patients. Heat shock protein beta-1 (HSPB1) plays a tumor promoting role in PC by inhibiting ferroptosis. This study aims to explore whether high expression of HSPB1 was responsible for ferroptosis and gemcitabine (GEM) resistance in PC. Here, we found that HSPB1 was upregulated in GEM-resistant PC cells and tumor tissues, as confirmed by RT-qPCR and Western blotting assays. Knockdown of HSPB1 enhanced GEM sensitivity, decreased the abilities of proliferation and invasion, and promoted apoptosis in GEM-resistant PC cells. Utilizing commercial kits, HSPB1 inhibition triggered ferroptosis, as indicated by increased levels of reactive oxygen species, malondialdehyde, and Fe2+, along with reduced glutathione (GSH) levels. Furthermore, the methylation specific PCR (MSP) results demonstrated a significant decrease in the methylation level of annexin A2 (ANXA2) CpG. The Chromatin immunoprecipitation (ChIP), ChIP-Re-ChIP, and Co-IP experiments revealed that HSPB1 interacts with lysine-specific histone demethylase 1A (KDM1A), recruiting KDM1A-CoREST complex to the ANXA2 promoter to enhance ANXA2 expression through demethylation of H3K9me2. Additionally, ANXA2 depletion further inhibited cell proliferation and invasion and induced ferroptosis in KDM1A-silenced cells, whereas ANXA2 overexpression produced the opposite effects. Finally, HSPB1 overexpression reduced gemcitabine sensitivity by promoting tumor growth in nude mice. Altogether, HSPB1 promoted ANXA2 expression by facilitating H3K9me2 demethylation through the recruitment of KDM1A-CoREST complex to the ANXA2 promoter, thereby inhibiting ferroptosis and enhancing GEM resistance in PC. These data provided a new insight for overcoming GEM-resistant PC.

Exosomes: their role and therapeutic potential in overcoming drug resistance of gastrointestinal cancers

Gastrointestinal cancers are prevalent malignant neoplasms in clinical medicine. The development of drug resistance in gastrointestinal cancers result in tumor recurrence and metastasis and greatly diminish the efficacy of treatment. Exosomes, as the shuttle of intercellular molecular cargoes in tumor micro-environment, secreted from tumor and stromal cells mediate drug resistance by regulating epithelial-mesenchymal transition, drug efflux, stem-like phenotype and cell metabolism. Meanwhile, exosomes have already received tremendous attention in biomedical study as potential drug resistant biomarkers as well as treatment strategy in gastrointestinal cancers. Primary challenge to implement this potential is the ability to obtain high-grade exosomes efficiently; however, exosomes lack standard protocols for their processing and characterization. Furthermore, this field suffers from insufficient standardized reference materials and workflow for purification, detection and analysis of exosomes with defined biological properties. This review summarize the unique biogenesis, composition and novel detection methods of exosomes and informed the underlying correlation between exosomes and drug resistance of gastrointestinal cancers. Moreover, the clinical applications of exosomes are also summarized, might providing novel therapy for the individual treatment of gastrointestinal cancers.

Exosome-mediated ferroptosis in the tumor microenvironment: from molecular mechanisms to clinical application

Ferroptosis in the tumor microenvironment (TME) plays a crucial role in the development, metastasis, immune escape, and drug resistance of various types of cancer. A better understanding of ferroptosis in the TME could illuminate novel aspects of this process and promote the development of targeted therapies. Compelling evidence indicates that exosomes are key mediators in regulating the TME. In this respect, it is now understood that exosomes can deliver biologically functional molecules to recipient cells, influencing cancer progression by reprogramming the metabolism of cancer cells and their surrounding stromal cells through ferroptosis. In this review, we focus on the role of exosomes in the TME and describe how they contribute to tumor reprogramming, immunosuppression, and the formation of pre-metastatic niches through ferroptosis. In addition, we highlight exosome-mediated ferroptosis as a potential target for cancer therapy and discuss strategies employing exosomes in ferroptosis treatment. Finally, we outline the current applications and challenges of targeted exosome-mediated ferroptosis therapy in tumor immunotherapy and chemotherapy. Our aim is to advance research on the link between exosomes and ferroptosis in the TME, and we pose questions to guide future studies in this area.

Metabolic Reprogramming of Gastric Cancer Revealed by a Liquid Chromatography-Mass Spectrometry-Based Metabolomics Study

BACKGROUND/OBJECTIVES

Gastric cancer (GC) is a prevalent malignant tumor worldwide, with its pathological mechanisms largely unknown. Understanding the metabolic reprogramming associated with GC is crucial for the prevention and treatment of this disease. This study aims to identify significant alterations in metabolites and pathways related to the development of GC.

METHODS

A liquid chromatography-mass spectrometry-based non-targeted metabolomics data acquisition was performed on paired tissues from 80 GC patients. Differences in metabolic profiles between tumor and adjacent normal tissues were first investigated through univariate and multivariate statistical analyses. Additionally, differential correlation network analysis and a newly proposed network analysis method (NAM) were employed to explore significant metabolite pathways and subnetworks related to tumorigenesis and various TNM stages of GC.

RESULTS

Over half of the annotated metabolites exhibited significant alterations. Phosphatidylcholine (PC)_30_0 and fatty acid C20_3 demonstrated strong diagnostic performance for GC, with AUCs of 0.911 and 0.934 in the discovery and validation sets, respectively. Differential correlation network analysis revealed significant fatty acid-related metabolic reprogramming in GC with elevated levels of medium-chain acylcarnitines and increased activity of medium-chain acyl-CoA dehydrogenase, firstly observed in clinical GC tissues. Of note, using NAM, two correlation subnetworks were identified as having significant alterations across different TNM stages, centered with choline and carnitine C4_0-OH, respectively.

CONCLUSIONS

The identified significant alterations in fatty acid metabolism and TNM-related metabolic subnetworks in GC tissues will facilitate future investigations into the metabolic reprogramming associated with gastric cancer.

Disulfidptosis classification of pancreatic carcinoma reveals correlation with clinical prognosis and immune profile

BACKGROUND

Disulfidptosis, a novel form of metabolism-related regulated cell death, is a promising intervention for cancer therapeutic intervention. Although aberrant expression of long-chain noncoding RNAs (lncRNAs) expression has been associated with pancreatic carcinoma (PC) development, the biological properties and prognostic potential of disulfidptosis-related lncRNAs (DRLs) remain unclear.

METHODS

We obtained RNA-seq data, clinical data, and genomic mutations of PC from the TCGA database, and then determined DRLs. We developed a risk score model and analyzed the role of risk score in the predictive ability, immune cell infiltration, immunotherapy response, and drug sensitivity.

RESULTS

We finally established a prognostic model including three DRLs (AP005233.2, FAM83A-AS1, and TRAF3IP2-AS1). According to Kaplan-Meier curve analysis, the survival time of patients in the low-risk group was significantly longer than that in the high-risk group. Based on enrichment analysis, significant associations between metabolic processes and differentially expressed genes were assessed in two risk groups. In addition, we observed significant differences in the tumor immune microenvironment landscape. Tumor Immune Dysfunction and Rejection (TIDE) analysis showed no statistically significant likelihood of immune evasion in both risk groups. Patients exhibiting both high risk and high tumor mutation burden (TMB) had the poorest survival times, while those falling into the low risk and low TMB categories showed the best prognosis. Moreover, the risk group identified by the 3-DRLs profile showed significant drug sensitivity.

CONCLUSIONS

Our proposed 3-DRLs-based feature could serve as a promising tool for predicting the prognosis, immune landscape, and treatment response of PC patients, thus facilitating optimal clinical decision-making.

Extracellular vesicles in tumor immunity: mechanisms and novel insights

Extracellular vesicles (EVs), nanoscale vesicles secreted by cells, have attracted considerable attention in recent years due to their role in tumor immunomodulation. These vesicles facilitate intercellular communication by transporting proteins, nucleic acids, and other biologically active substances, and they exhibit a dual role in tumor development and immune evasion mechanisms. Specifically, EVs can assist tumor cells in evading immune surveillance and attack by impairing immune cell function or modulating immunosuppressive pathways, thereby promoting tumor progression and metastasis. Conversely, they can also transport and release immunomodulatory factors that stimulate the activation and regulation of the immune system, enhancing the body's capacity to combat malignant diseases. This dual functionality of EVs presents promising avenues and targets for tumor immunotherapy. By examining the biological characteristics of EVs and their influence on tumor immunity, novel therapeutic strategies can be developed to improve the efficacy and relevance of cancer treatment. This review delineates the complex role of EVs in tumor immunomodulation and explores their potential implications for cancer therapeutic approaches, aiming to establish a theoretical foundation and provide practical insights for the advancement of future EVs-based cancer immunotherapy strategies.

N-glycosylation Modification of CTSD Affects Liver Metastases in Colorectal Cancer

Liver metastasis is the primary factor contributing to unfavorable prognosis in colorectal cancer (CRC). Although N-glycosylation is implicated in metastasis, there is a notable paucity of comprehensive studies addressing the N-glycosylation proteomics associated with liver metastasis in CRC. In this study, N-glycosylated proteins and N-glycosylation sites of differential expression between primary lesions and paired liver metastatic lesions are identified. Cathepsin D (CTSD) is further screened as a potentially pivotal N-glycosylated protein in CRC liver metastasis. Glycosyltransferases complex DDOST and STT3B can regulate N-glycosylation modification at residue 263 of CTSD (a protease), thereby affecting CTSD protease to lyse ACADM. ACADM can regulate ferroptosis-related proteins (ACSL4, SLC7A11, and GPX4) to further influence the invasion and metastasis of CRC cells. This newly discovered mechanism provides potential therapeutic targets for CRC treatment and insights for controlling CRC progression and metastasis.

Emerging roles of non-coding RNAs in modulating the PI3K/Akt pathway in cancer

Cancer progression results from the dysregulation of molecular pathways, each with unique features that can either promote or inhibit tumor growth. The complexity of carcinogenesis makes it challenging for researchers to target all pathways in cancer therapy, emphasizing the importance of focusing on specific pathways for targeted treatment. One such pathway is the PI3K/Akt pathway, which is often overexpressed in cancer. As tumor cells progress, the expression of PI3K/Akt increases, further driving cancer advancement. This study aims to explore how ncRNAs regulate the expression of PI3K/Akt. NcRNAs are found in both the cytoplasm and nucleus, and their functions vary depending on their location. They can bind to the promoters of PI3K or Akt, either reducing or increasing their expression, thus influencing tumorigenesis. The ncRNA/PI3K/Akt axis plays a crucial role in determining cell proliferation, metastasis, epithelial-mesenchymal transition (EMT), and even chemoresistance and radioresistance in human cancers. Anti-tumor compounds can target ncRNAs to modulate the PI3K/Akt axis. Moreover, ncRNAs can regulate the PI3K/Akt pathway both directly and indirectly.

Causal associations of tea consumption on risk of pancreatic adenocarcinoma and the mediating role of vascular endothelial growth factor D levels

Tea is one of the most widely consumed beverages in the world. However, the association between tea and risk of pancreatic adenocarcinoma remains controversial. This study aimed to investigate the causal relationship between tea consumption and risk of pancreatic adenocarcinoma and to explore their mediating effects. The two-sample Mendelian randomisation (MR) analysis showed an inverse causal relationship between tea intake and pancreatic adenocarcinoma (OR: 0·111 (0·02, 0·85), P < 0·04). To examine the mediating effects, we explored the potential mechanisms by which tea intake reduces the risk of pancreatic adenocarcinoma. Based on the oral bioavailability and drug-like properties in Traditional Chinese Medicine Systems Pharmacology database, we selected the main active ingredients of tea. We screened out the fifteen representative targeted genes by Pharmmapper database, and the gene ontology enrichment analysis showed that these targeted genes were related to vascular endothelial growth factor (VEGF) pathway. The two-step MR analysis of results showed that only VEGF-D played a mediating role, with a mediation ratio of 0·230 (0·066, 0·394). In conclusion, the findings suggest that VEGF-D mediates the effect of tea intake on the risk of pancreatic adenocarcinoma.

Emerging role of tumor microenvironmental nutrients and metabolic molecules in ferroptosis: Mechanisms and clinical implications

In recent years, ferroptosis has gradually attracted increasing attention because of its important role in tumors. Ferroptosis resistance is an important cause of tumor metastasis, recurrence and drug resistance. Exploring the initiating factors and specific mechanisms of ferroptosis has become a key strategy to block tumor progression and improve drug sensitivity. As the external space in direct contact with tumor cells, the tumor microenvironment has a great impact on the biological function of tumor cells. The relationships between abnormal environmental characteristics (hypoxia, lactic acid accumulation, etc.) in the microenvironment and ferroptosis of tumor cells has not been fully characterized. This review focuses on the characteristics of the tumor microenvironment and summarizes the mechanisms of ferroptosis under different environmental factors, aiming to provide new insights for subsequent targeted therapy. Moreover, considering the presence of anticancer drugs in the microenvironment, we further summarize the mechanisms of ferroptosis to provide new strategies for the sensitization of tumor cells to drugs.

Exploring the impact of flavin homeostasis on cancer cell metabolism

Flavins and their associated proteins have recently emerged as compelling players in the landscape of cancer biology. Flavins, encompassing flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), serve as coenzymes in a multitude of cellular processes, such as metabolism, apoptosis, and cell proliferation. Their involvement in oxidative phosphorylation, redox homeostasis, and enzymatic reactions has long been recognized. However, recent research has unveiled an extended role for flavins in the context of cancer. In parallel, riboflavin transporters (RFVTs), FAD synthase (FADS), and riboflavin kinase (RFK) have gained prominence in cancer research. These proteins, responsible for riboflavin uptake, FAD biosynthesis, and FMN generation, are integral components of the cellular machinery that governs flavin homeostasis. Dysregulation in the expression/function of these proteins has been associated with various cancers, underscoring their potential as diagnostic markers, therapeutic targets, and key determinants of cancer cell behavior. This review embarks on a comprehensive exploration of the multifaceted role of flavins and of the flavoproteins involved in nucleus-mitochondria crosstalk in cancer. We journey through the influence of flavins on cancer cell energetics, the modulation of RFVTs in malignant transformation, the diagnostic and prognostic significance of FADS, and the implications of RFK in drug resistance and apoptosis. This review also underscores the potential of these molecules and processes as targets for novel diagnostic and therapeutic strategies, offering new avenues for the battle against this relentless disease.

Developing a machine learning-based prognosis and immunotherapeutic response signature in colorectal cancer: insights from ferroptosis, fatty acid dynamics, and the tumor microenvironment

Instruction

Colorectal cancer (CRC) poses a challenge to public health and is characterized by a high incidence rate. This study explored the relationship between ferroptosis and fatty acid metabolism in the tumor microenvironment (TME) of patients with CRC to identify how these interactions impact the prognosis and effectiveness of immunotherapy, focusing on patient outcomes and the potential for predicting treatment response.

Methods

Using datasets from multiple cohorts, including The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), we conducted an in-depth multi-omics study to uncover the relationship between ferroptosis regulators and fatty acid metabolism in CRC. Through unsupervised clustering, we discovered unique patterns that link ferroptosis and fatty acid metabolism, and further investigated them in the context of immune cell infiltration and pathway analysis. We developed the FeFAMscore, a prognostic model created using a combination of machine learning algorithms, and assessed its predictive power for patient outcomes and responsiveness to treatment. The FeFAMscore signature expression level was confirmed using RT-PCR, and ACAA2 progression in cancer was further verified.

Results

This study revealed significant correlations between ferroptosis regulators and fatty acid metabolism-related genes with respect to tumor progression. Three distinct patient clusters with varied prognoses and immune cell infiltration were identified. The FeFAMscore demonstrated superior prognostic accuracy over existing models, with a C-index of 0.689 in the training cohort and values ranging from 0.648 to 0.720 in four independent validation cohorts. It also responses to immunotherapy and chemotherapy, indicating a sensitive response of special therapies (e.g., anti-PD-1, anti-CTLA4, osimertinib) in high FeFAMscore patients.

Conclusion

Ferroptosis regulators and fatty acid metabolism-related genes not only enhance immune activation, but also contribute to immune escape. Thus, the FeFAMscore, a novel prognostic tool, is promising for predicting both the prognosis and efficacy of immunotherapeutic strategies in patients with CRC.

Breaking the Barriers of Therapy Resistance: Harnessing Ferroptosis for Effective Hepatocellular Carcinoma Therapy

Ferroptosis is a type of cell death that relies on iron and is distinguished by the occurrence of lipid peroxidation and the buildup of reactive oxygen species. Ferroptosis has been demonstrated to have a significant impact on the advancement and resistance to treatment of hepatocellular carcinoma (HCC), thereby highlighting its potential as a viable therapeutic target. Ferroptosis was observed in HCC tissues in contrast to normal liver tissue. The inhibition of ferroptosis has been found to increase the viability of HCC cells and decrease their susceptibility to various anticancer therapies, including chemotherapy, radiotherapy, and immune checkpoint blockade. The administration of drugs that directly modulate ferroptosis regulators or induce excessive production of lipid-reactive oxygen species has demonstrated the potential to enhance the responsiveness of drug-resistant HCC cells to treatment. However, the precise mechanism underlying this phenomenon remains ambiguous. This review presents a comprehensive overview of the crucial role played by ferroptosis in enhancing the efficacy of treatment for hepatocellular carcinoma (HCC). The main aim of this study is to examine the feasibility of utilizing ferroptosis as a therapeutic approach to improve the efficacy of HCC treatment and overcome drug resistance.

Role of Exosomes in Cancer and Aptamer-Modified Exosomes as a Promising Platform for Cancer Targeted Therapy

Exosomes are increasingly recognized as important mediators of intercellular communication in cancer biology. Exosomes can be derived from cancer cells as well as cellular components in tumor microenvironment. After secretion, the exosomes carrying a wide range of bioactive cargos can be ingested by local or distant recipient cells. The released cargos act through a variety of mechanisms to elicit multiple biological effects and impact most if not all hallmarks of cancer. Moreover, owing to their excellent biocompatibility and capability of being easily engineered or modified, exosomes are currently exploited as a promising platform for cancer targeted therapy. In this review, we first summarize the current knowledge of roles of exosomes in risk and etiology, initiation and progression of cancer, as well as their underlying molecular mechanisms. The aptamer-modified exosome as a promising platform for cancer targeted therapy is then briefly introduced. We also discuss the future directions for emerging roles of exosome in tumor biology and perspective of aptamer-modified exosomes in cancer therapy.

Pioglitazone, a peroxisome proliferator‑activated receptor γ agonist, induces cell death and inhibits the proliferation of hypoxic HepG2 cells by promoting excessive production of reactive oxygen species

Hypoxia is a hallmark of solid tumors. Hypoxic cancer cells adjust their metabolic characteristics to regulate the production of cellular reactive oxygen species (ROS) and facilitate ROS-mediated metastasis. Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that regulates the transcription of fatty acid metabolism-related genes that have a key role in the survival and proliferation function of hypoxic cancer cells. In the present study, mRNA expression in HepG2 cells under chemically induced hypoxia was assessed. The protein expression levels of hypoxia-inducible factor 1α (HIF-1α) were measured using western blotting. Following treatment with the PPARγ agonist pioglitazone, cell viability was assessed using a Cell Counting Kit-8 assay, whilst cell proliferation and death were determined using 5-ethynyl-2'-deoxyuridine incorporation staining, and calcein-acetoxymethyl ester and propidium iodide staining, respectively. Cellular ROS production was assessed using dihydroethidium staining. Cobalt chloride was used to induce hypoxia in HepG2 cells, which was evaluated using HIF-1α expression. The results revealed that the mRNA expression of PPARγ, CD36, acetyl-co-enzyme A dehydrogenase (ACAD) medium chain (ACADM) and ACAD short-chain (ACADS) was downregulated in hypoxic HepG2 cells. The PPARγ agonist pioglitazone decreased the cell viability of hypoxic HepG2 cells by inhibiting cell proliferation and inducing cell death. Following treatment with the PPARγ agonist pioglitazone, hypoxic HepG2 cells produced excessive ROS. ROS-mediated cell death induced by the PPARγ agonist pioglitazone was rescued with the antioxidant N-acetyl-L-cysteine. The downregulated mRNA expression of PPARγ, CD36, ACADM and ACADS was not reverted by a PPARγ agonist in hypoxic HepG2 cells. By contrast, the PPARγ agonist suppressed the mRNA expression of BCL2, which was upregulated in hypoxic HepG2 cells. In summary, the PPARγ agonist stimulated excessive ROS production to inhibit cell proliferation and increase the death of hypoxic HepG2 cells by decreasing BCL2 mRNA expression, suggesting a negative association between PPARγ and BCL2 in the regulation of ROS production in hypoxic HepG2 cells.

Paris saponin VII promotes ferroptosis to inhibit breast cancer via Nrf2/GPX4 axis

Breast cancer (BC) is one of the malignancies threatening the woman's health. Our study aims to explore the underlying mechanism behind the anti-tumor function of Paris saponin VII (PS VII) in BC. Xenografting experiment was conducted to monitor the tumor growth. The Ki67 and 4-HNE expression were analyzed via immunohistochemical assay. After different treatments, the cell viability, proliferation, invasion, and migration capacity of BC cells were measured by the CCK-8, colony formation, transwell, and wound healing assays, respectively. The ratio of GSH/GSSG was measured by the GSH/GSSG ratio detection assay kit. The lipid ROS and Fe2+ levels were quantified by flow cytometry analysis. The expressions of TFR1, ACSL4, Nrf2, and GPX4 were measured via western blotting. Compared with the Ctrl group, the tumor volumes, and Ki67 expression were markedly reduced in PS VII groups, and the BC cell viability was decreased by PS VII treatment in a dose-dependent manner. The colony numbers, invasive cells, and migration rates were also significantly decreased by PS VII treatment. Then, the Nrf2 as well as GPX4 expressions were decreased and TFR1 expression was increased by PS VII treatment in vitro and in vivo, while there was no difference in ACSL4 expression between Ctrl and PS VII groups. Moreover, the above effects of PS VII could not be observed in GPX4 knockdown cells. PS VII can promote ferroptosis to inhibit BC via the Nrf2/GPX4 axis, which innovatively suggests the pro-ferroptosis effect and therapeutic potential of PS VII in BC.