Redox homeostasis is a lifelong pursuit of cancer cells. Depending on the context, reactive oxygen species (ROS) exert paradoxical effects on cancers; an appropriate concentration stimulates tumorigenesis and supports the progression of cancer cells, while an excessive concentration leads to cell death. The upregulated antioxidant system in cancer cells limits ROS to a tumor-promoting level. In cancers, redox regulation interacts with tumor initiation, proliferation, metastasis, programmed cell death, autophagy, metabolic reprogramming, the tumor microenvironment, therapies, and therapeutic resistance to facilitate cancer development. This review discusses redox control and the major hallmarks of cancer.

Background: Pancreatic cancer exhibits limited clinical responses to immunotherapy, highlighting the need for new strategies to counteract its immunosuppressive microenvironment. Although metabolic reprogramming and epigenetic changes contribute to malignancy, the impact of lactate-driven histone lactylation on the tumour microenvironment (TME) has not been fully explored. Objective: This study aims to investigate the role of histone lactylation in pancreatic cancer, focusing on its effects on cholesterol metabolism and antitumour immunity. Designs: Global lactylome profiling was conducted to identify novel epigenetic mechanisms driven by lactate-induced histone lactylation. Mechanisms were investigated via RNA sequencing, CUT&Tag, immunoprecipitation-mass spectrometry and GST-pull down. Mass cytometry by time-of-flight, in vitro co-culture system, orthotopic pancreatic cancer models and flow cytometry were used to explore Acetyl-CoA acetyltransferase (ACAT2) functions. A proteolysis-targeting chimaera (PROTAC) was developed to degrade ACAT2. Results: Global lactylome profiling revealed that lactate-driven histone lactylation, particularly H3K18la, promotes the transcriptional activation of ACAT2. ACAT2 acetylates mitochondrial carrier homolog 2 (MTCH2), stabilising it and disrupting oxidative phosphorylation, which increases lactate production and fuels a positive feedback loop in pancreatic cancer. This loop facilitates the delivery of cholesterol via small extracellular vesicles (sEVs), polarising tumour-associated macrophages toward an immunosuppressive M2 phenotype. Additionally, the PROTAC targeting ACAT2 enhanced the efficacy of immune checkpoint blockade therapy in vivo . Conclusions: Our findings highlight the critical role of the H3K18la/ACAT2/sEV-cholesterol axis in TME reprogramming. Targeting this pathway may improve anti-PD-1 therapy response in pancreatic cancer, providing a novel therapeutic strategy by linking histone lactylation, cholesterol metabolic reprogramming and immune modulation.

The overall five-year survival rate of pancreatic cancer has hardly changed in the past few decades (less than 10%) because of resistance to all known therapies, including chemotherapeutic drugs. In the past few decades, gemcitabine has been at the forefront of treatment for pancreatic ductal adenocarcinoma, but more strategies to combat drug resistance need to be explored. One promising possibility is ferroptosis, a form of a nonapoptotic cell death that depends on intracellular iron and occurs through the accumulation of lipid reactive oxygen species, which are significant in drug resistance. In this article, we reviewed gemcitabine-resistance mechanisms; assessed the relationship among ferroptosis, tumorigenesis and gemcitabine resistance, and explored a new treatment method for pancreatic cancer.

RNA N6-methyladenosine (m⁶A) is an emerging regulator of mRNA modifications and represents a novel player in tumorigenesis. Although it has functional significance in both pathological and physiological processes, the role of m⁶A modification in pancreatic ductal cancer (PDAC) remains elusive. Here, we showed that high fat mass and obesity-associated gene (FTO) expression was associated with a poor prognosis in PDAC patients and that suppression of FTO expression inhibited cell proliferation. Here, m⁶A sequencing (m⁶A-seq) was performed to screen genes targeted by FTO. The effects of FTO stimulation on the biological characteristics of pancreatic cancer cells, including proliferation and colony formation, were investigated in vitro and in vivo. The results indicate that FTO directly targets platelet-derived growth factor C (PDGFC) and stabilizes its mRNA expression in an m⁶A-YTHDF2-dependent manner. m⁶A-methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR), RNA immunoprecipitation (RIP), and luciferase reporter assays were employed to validate the specific binding of FTO to PDGFC. PDGFC upregulation led to reactivation of the Akt signaling pathway, promoting cell growth. Overall, our study reveals that FTO downregulation leads to increased m⁶A modifications in the 3ʹ UTR of PDGFC and then modulates the degradation of its transcriptional level in an m⁶A-YTHDF2-dependent manner, highlighting a potential therapeutic target for PDAC treatment and prognostic prediction.

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal tumor with limited treatment options and poor patient survival. Circular RNAs (circRNA) play crucial regulatory roles in the occurrence and development of various cancers, including PDAC. In this study, using circRNA sequencing of diverse PDAC samples, we identified circRREB1 as an oncogenic circRNA that is significantly upregulated in PDAC and is correlated with an unfavorable patient prognosis. Functionally, loss of circRREB1 markedly inhibited glycolysis and stemness, whereas elevated circRREB1 elicited the opposite effects. Mechanistically, circRREB1 interacted with PGK1, disrupting the association between PTEN and PGK1 and increasing PGK1 phosphorylation to activate glycolytic flux. Moreover, circRREB1 promoted WNT7B transcription by directly interacting with YBX1 and facilitating its nuclear translocation, consequently activating the Wnt/β-catenin signaling pathway to maintain PDAC stemness. Overall, these results highlight circRREB1 as a key regulator of metabolic and stemness properties of PDAC. Significance: CircRREB1 stimulates PGK1 to induce glycolysis and activates the Wnt/β-catenin signaling pathway to maintain stemness in pancreatic cancer, indicating the potential of circRREB1 as a biomarker and therapeutic target.