Novel perspective in pancreatic cancer therapy: Targeting ferroptosis pathway

Ferroptosis-related LINC02535/has-miR-30c-5p/EIF2S1 axis as a novel prognostic biomarker involved in immune infiltration and progression of PDAC

BACKGROUND

PDAC, also known as pancreatic ductal adenocarcinoma, is often diagnosed at a late stage due to nonspecific symptoms and a distinct lack of reliable biomarkers for timely diagnosis. Ferroptosis, a novel non-apoptotic cell death mode discovered in recent years, is strongly linked to the progression of PDAC and the evasion of the immune system. The objective of this study is to discover a novel ceRNA biomarker associated with ferroptosis and investigate its possible molecular mechanisms and therapeutic potential in PDAC.

METHODS

Based on the FerrDb and TCGA databases, the R survival package was used to screen for ferroptosis-related mRNAs associated with PDAC prognosis. The ferroptosis-related ceRNA network was identified by miRTarBase, miRNet, and starBase and visualized using Cytoscape. The LASSO regression analysis was used to build a risk model associated with ceRNA. Additionally, we investigated the correlation between the ceRNA axis and the infiltration of immune cells in PDAC by employing the ssGSEA algorithm. Spearman correlation analysis was used to investigate the association between the ceRNA network and the expression levels of immune checkpoint genes in PDAC. The prediction of potential medications for PAAD patients with high risk scores was conducted using the R package oncoPredict and the Genomics of Drug Sensitivity in Cancer (GDSC) repository. Expression levels of LINC02535 in clinical specimens and PDAC cell lines were determined using qRT-PCR. CCK-8, colony formation, EdU, wound healing, and transwell assays were performed to assess the impact of reducing LINC02535 on the growth, migration, and invasion of PDAC cell lines BxPC3 and PANC1.

RESULTS

We first discovered a new LINC02535/miR-30c-5p/EIF2S1 axis associated with ferroptosis and created a prognostic nomogram for predicting overall survival. Meanwhile, the risk scores of the LINC02535/miR-30c-5p/EIF2S1 axis associated with ferroptosis were linked to immune subtypes in PDAC. The high immune infiltration subtype exhibited elevated ceRNA risk scores and EIF2S1 expression. The correlation analysis revealed a positive correlation between ceRNA risk scores and four immune cells, namely Activated CD4 T cell, Memory B cell, Neutrophil, and Type 2 T helper cell, as well as four immune checkpoint genes, namely CD274, HAVCR2, PDCD1LG2, and TIGIT. The analysis of drug sensitivity indicated that individuals with a high-risk score may exhibit greater sensitivity to inhibitors targeting MEK1/2 compared to those with a low-risk score. In our validation experiments, it was observed that the expression of LINC02535 was increased in both PDAC tissues and cell lines. Additionally, the inhibition of LINC02535 resulted in decreased proliferation, migration, and invasion of PDAC cells. Rescue experiments demonstrated that LINC02535 promoted PDAC cell growth and metastasis by upregulating EIF2S1 expression.

CONCLUSION

To summarize, a novel ferroptosis-associated LINC02535/miR-30c-5p/EIF2S1 ceRNA network for PDAC patients was established. The analysis of this network's functionality offers potential insights for clinical decision-making and the advancement of precision medicine.

Gemcitabine-loaded chitosan nanoparticles enhanced apoptotic and ferroptotic response of gemcitabine treatment alone in the pancreatic cancer cells in vitro

Gemcitabine (GEM) is a first-line treatment for pancreatic ductal adenocarcinoma (PDAC) patients, causing side effects and poor overall survival. Eighty percent of patients often develop resistance rapidly to GEM. Developing therapeutic approaches and increasing sensitivity to gemcitabine in PDAC has become one of the challenges in cancer research. We synthesized GEM-loaded NPs prepared with a method that combines ultrasonication and ionotropic gelation to overcome GEM-related limitations in PDAC. CFPAC-1 cells were treated with increased concentrations of GEM, empty chitosan, and GEM-loaded NPs (0.66, 1.32, 2.64, 5.32 µg/ml) for up to 48 h. Empty chitosan NPs did not show toxicity on L929 cells. Antioxidant enzyme activities, including glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6-PGD), glutathione reductase (GR), glutathione s-transferase (GST), and glutathione peroxidase (GPx), significantly reduced in GEM-loaded NPs compared to the GEM associated with increased oxidative stress, PPP, and glycolysis. Bcl-xL, NOXA/mcl-1, and Ca2+ levels significantly increased in GEM-loaded NP-administered cells compared to the GEM and control groups. In contrast, JNK, p38, STAT3, Akt, and CREB levels significantly decreased in the GEM-loaded NP group, addressing enhanced apoptotic response compared to the GEM alone. Increased ferroptosis activity in GEM-loaded NP-administered groups has been validated via decreased antioxidant enzyme activities, increased cytosolic Fe, Zn, Mg, and Mn levels, and reduced GPx activity compared to the GEM and control groups. For the first time in the literature, we showed biocompatible GEM-loaded NPs enhanced apoptotic and ferroptotic response in CFPAC-1 cells via downregulation of antioxidant, glycolysis, and PPP metabolism compared to the GEM alone.

The Role of Nrf2 in the Regulation of Mitochondrial Function and Ferroptosis in Pancreatic Cancer

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) represents the master regulator of the cellular antioxidant response and plays a critical role in tumorigenesis. This includes a preventive effect of Nrf2 on cell death through ferroptosis, which represents an essential mechanism of therapy resistance in malignant tumors, such as pancreatic ductal adenocarcinoma (PDAC) as one of the most aggressive and still incurable tumors. Addressing this issue, we provide an overview on Nrf2 mediated antioxidant response with particular emphasis on its effect on mitochondria as the organelle responsible for the execution of ferroptosis. We further outline how deregulated Nrf2 adds to the progression and therapy resistance of PDAC, especially with respect to the role of ferroptosis in anti-cancer drug mediated cell killing and how this is impaired by Nrf2 as an essential mechanism of drug resistance. Our review further discusses recent approaches for Nrf2 inhibition by natural and synthetic compounds to overcome drug resistance based on enhanced ferroptosis. Finally, we provide an outlook on therapeutic strategies based on Nrf2 inhibition combined with ferroptosis inducing drugs.

The predictive role of soluble programmed death ligand 1 in digestive system cancers

Introduction

The prognostic role of soluble programmed death ligand 1 (sPD-L1) in digestive system cancers (DSCs) remains inconclusive. This study aimed to explore the predictive value of sPD-L1 expression in DSCs.

Methods

Comprehensive searches were run on the electronic databases (PubMed, Web of Science, EMBASE, and the Cochrane Library) to identify studies that assessed the prognostic role of sPD-L1 in DSCs. Review Manager software (version 5.3) was used for all analyses. Pooled data for survival outcomes were measured as hazard ratios (HRs), 95% confidence intervals (CIs), and odds ratios and their 95% CIs.

Results

The search identified 18 studies involving 2,070 patients with DSCs. The meta-outcome revealed that a high level of sPD-L1 was related to poorer overall survival (HR, 3.06; 95% CI: 2.22-4.22, p<0.001) and disease-free survival (HR, 2.53; 95% CI: 1.67-3.83, p<0.001) in DSCs. Individually, the prognostic significance of high level of sPD-L1 expression was the highest in hepatic cell carcinoma (HR, 4.76; p<0.001) followed by gastric cancer (HR=3.55, p<0.001).

Conclusion

sPD-L1 may be a prognostic factor in DSCs for overall survival and disease-free survival. Inflammatory cytokines, treatment approaches, and other factors may affect the expression of sPD-L1. Therefore, the prognostic value of sPD-L1 for recurrence and metastasis should be further investigated. sPD-L1 may also predict response to treatment. Well-designed prospective studies with standard assessment methods should be conducted to determine the prognostic value of sPD-L1 in DSCs.

The role of amino acid metabolism alterations in pancreatic cancer: From mechanism to application

The incidence of pancreatic cancer is increasing in both developed and developing Nations. In recent years, various research evidence suggested that reprogrammed metabolism may play a key role in pancreatic cancer tumorigenesis and development. Therefore, it has great potential as a diagnostic, prognostic and therapeutic target. Amino acid metabolism is deregulated in pancreatic cancer, and changes in amino acid metabolism can affect cancer cell status, systemic metabolism in malignant tumor patients and mistakenly involved in different biological processes including stemness, proliferation and growth, invasion and migration, redox state maintenance, autophagy, apoptosis and even tumor microenvironment interaction. Generally, the above effects are achieved through two pathways, energy metabolism and signal transduction. This review aims to highlight the current research progress on the abnormal alterations of amino acids metabolism in pancreatic cancer, how they affect tumorigenesis and development of pancreatic cancer and the application prospects of them as diagnostic, prognostic and therapeutic targets.

Liposome-based diagnostic and therapeutic applications for pancreatic cancer

Pancreatic cancer is one of the harshest and most challenging cancers to treat, often labeled as incurable. Chemotherapy continues to be the most popular treatment yet yields a very poor prognosis. The main barriers such as inefficient drug penetration and drug resistance, have led to the development of drug carrier systems. The benefits, ease of fabrication and modification of liposomes render them as ideal future drug delivery systems. This review delves into the versatility of liposomes to achieve various mechanisms of treatment for pancreatic cancer. Not only are there benefits of loading chemotherapy drugs and targeting agents onto liposomes, as well as mRNA combined therapy, but liposomes have also been exploited for immunotherapy and can be programmed to respond to photothermal therapy. Multifunctional liposomal formulations have demonstrated significant pre-clinical success. Functionalising drug-encapsulated liposomes has resulted in triggered drug release, specific targeting, and remodeling of the tumor environment. Suppressing tumor progression has been achieved, due to their ability to more efficiently and precisely deliver chemotherapy. Currently, no multifunctional surface-modified liposomes are clinically approved for pancreatic cancer thus we aim to shed light on the trials and tribulations and progress so far, with the hope for liposomal therapy in the future and improved patient outcomes. STATEMENT OF SIGNIFICANCE: Considering that conventional treatments for pancreatic cancer are highly associated with sub-optimal performance and systemic toxicity, the development of novel therapeutic strategies holds outmost relevance for pancreatic cancer management. Liposomes are being increasingly considered as promising nanocarriers for providing not only an early diagnosis but also effective, highly specific, and safer treatment, improving overall patient outcome. This manuscript is the first in the last 10 years that revises the advances in the application of liposome-based formulations in bioimaging, chemotherapy, phototherapy, immunotherapy, combination therapies, and emergent therapies for pancreatic cancer management. Prospective insights are provided regarding several advantages resulting from the use of liposome technology in precision strategies, fostering new ideas for next-generation diagnosis and targeted therapies of pancreatic cancer.

Emerging current trends and research focus related to pancreatic cancer metabolism: A bibliometric and visualized analysis

Background

As a malignant digestive system tumor, pancreatic cancer has unique metabolic characteristics. In recent years, the study of pancreatic cancer metabolism is in full swing, which provides a new direction for the treatment of pancreatic cancer patients. However, there is no systematic report of pancreatic cancer metabolism. In this paper, bibliometrics and visualization methods were used to analyze the number of publications, countries/regions, authors, institutions, journals, co-cited references, and keywords of pancreatic cancer metabolism articles, to summarize the research trends and predict research hotspots.

Methods

We searched, screened and downloaded articles on pancreatic cancer metabolism through the Web of Science Core Collection (WoSCC). Using CiteSpace, VOSviewer and Bibliometrix Package to analyze publications, countries/regions, authors, institutions, journals, co-cited references, and keywords of pancreatic cancer metabolism to identify research trends and predict research hotspots.

Results

According to the inclusion and exclusion criteria, a total of 5,255 articles were retrieved during the period 1943-2022. The number of publications on pancreatic cancer metabolism is increasing year by year. The United States (n=1602, 30.49%), China (n=1074, 20.44%), and Italy (n=313, 5.96%) are the three countries with the largest number of publications and citations, and there is close cooperation between countries. LI J (n=55) is the most prolific author. FUDAN UNIV (n=348) is the most published institution. CANCERS (n=118), PLOS ONE (n=93), and CANCER RESEARCH (n=80) are the most popular journals in this field. "Nutriment-deficient environment", "cancer chemoprevention" and "targeting cancer stem cell" are the main areas of focus. "immunotherapy", "ferroptosis" and "targeted therapy" are hot keywords in recent years. Taking pancreatic cancer metabolism as an entry point to study the role of traditional Chinese medicine (TCM) mainly focuses on curcumin and resveratrol, lack of broader and deeper research on TCM.

Conclusions

The number of publications on pancreatic cancer metabolism has generally increased, and scholars have generally paid more attention to this field. "immunotherapy", "ferroptosis" and "targeted therapy" are the current research hotspots. The in-depth study of pancreatic cancer metabolism will provide new ideas for the treatment of pancreatic cancer.

Identifying a novel ferroptosis-related prognostic score for predicting prognosis in chronic lymphocytic leukemia

Background

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the western world. Although the treatment landscape for CLL is rapidly evolving, there are still some patients who develop drug resistance or disease refractory. Ferroptosis is a type of lipid peroxidation–induced cell death and has been suggested to have prognostic value in several cancers. Our research aims to build a prognostic model to improve risk stratification in CLL patients and facilitate more accurate assessment for clinical management.

Methods

The differentially expressed ferroptosis-related genes (FRGs) in CLL were filtered through univariate Cox regression analysis based on public databases. Least absolute shrinkage and selection operator (LASSO) Cox algorithms were performed to construct a prognostic risk model. CIBERSORT and single-sample gene set enrichment analysis (ssGSEA) were performed to estimate the immune infiltration score and immune-related pathways. A total of 36 CLL patients in our center were enrolled in this study as a validation cohort. Moreover, a nomogram model was established to predict the prognosis.

Results

A total of 15 differentially expressed FRGs with prognostic significance were screened out. After minimizing the potential risk of overfitting, we constructed a novel ferroptosis-related prognostic score (FPS) model with nine FRGs (AKR1C3, BECN1, CAV1, CDKN2A, CXCL2, JDP2, SIRT1, SLC1A5, and SP1) and stratified patients into low- and high-risk groups. Kaplan–Meier analysis showed that patients with high FPS had worse overall survival (OS) (P<0.0001) and treatment-free survival (TFS) (P<0.0001). ROC curves evaluated the prognostic prediction ability of the FPS model. Additionally, the immune cell types and immune-related pathways were correlated with the risk scores in CLL patients. In the validation cohort, the results confirmed that the high-risk group was related to worse OS (P<0.0001), progress-free survival (PFS) (P=0.0140), and TFS (P=0.0072). In the multivariate analysis, only FPS (P=0.011) and CLL-IPI (P=0.010) were independent risk indicators for OS. Furthermore, we established a nomogram including FPS and CLL-IPI that could strongly and reliably predict individual prognosis.

Conclusion

A novel FPS model can be used in CLL for prognostic prediction. The model index may also facilitate the development of new clinical ferroptosis-targeted therapies in patients with CLL.

CIRBP Regulates Pancreatic Cancer Cell Ferroptosis and Growth by Directly Binding to p53

Pancreatic cancer is one of the most malignant gastrointestinal tumors, and it is of great significance to explore the molecular mechanism of its progression and find new biological therapeutic targets. CIRBP is a cold-induced protein that plays a key role in many physiological and pathological processes, but its role in pancreatic cancer is still unclear. The expression of CIRBP in pancreatic cancer tissues was slightly lower than that in normal tissues, and the high expression of CIRBP was beneficial to survival. At the same time, immunohistochemical detection showed that the expression level of CIRBP in the cytoplasm of cancer tissues was significantly lower than that of adjacent tissues; survival curve analysis showed that pancreatic cancer patients with high nuclear CIRBP expression had a longer overall survival period. RIP results showed that CIRBP antibody significantly enriched p53 RNA, indicating that it could directly bind to p53. Cold treatment of pancreatic cancer cells significantly induced the expression of CIRBP, DPP4, NOX1, and FTH1 and inhibited the expression of p53 and GPX4. Cold induction enhanced the accumulation of Fe²⁺ in cells, promoted the generation of ROS, and inhibited the expression of GSH-Px. Therefore, cold induction promotes the process of ferroptosis by inducing the expression of CIRBP and then regulating key factors such as p53 and GPX4. In addition, cold induction significantly inhibited the proliferation of pancreatic cancer cells and induced cell apoptosis, but after the addition of ferroptosis inhibitor, cell proliferation and apoptosis did not change significantly. Therefore, CIRBP acts as a tumor suppressor gene in pancreatic cancer and induces ferroptosis through the p53/GPX4 pathway to inhibit cell growth, which may be an important target for the diagnosis and treatment of pancreatic cancer.