Aberrant arachidonic acid (AA) metabolism is a hallmark of cancer, and cytosolic phospholipase A2 (PLA2G4A) is the rate-limiting enzyme that initiates this cascade. However, the cell-intrinsic role of PLA2G4A and its downstream signaling mechanisms in non-small cell lung cancer (NSCLC) remain poorly understood. Here, we show that PLA2G4A is significantly upregulated in NSCLC patients and cell lines. Gain-of-function experiments in 16HBE normal bronchial epithelial cells demonstrate that ectopic PLA2G4A expression promotes proliferation, induces epithelial-mesenchymal transition, and cooperates with MYC to drive tumor formation in vivo. Conversely, CRISPR-Cas9-mediated knockout of PLA2G4A suppresses cell proliferation, soft agar colony formation, and invasion, while inducing G1 phase arrest and apoptosis. In vivo, PLA2G4A knockout inhibits tumor growth and lung colonization. Mechanistically, transcriptomics and biochemical analysis reveal that PLA2G4A knockout reduces IL-1β expression and suppresses MAPK pathway activity, leading to decreased phosphorylation of heat shock factor 1 (HSF1). Pharmacological inhibition of IL-1β phenocopies these effects, and ectopic HSF1 expression rescues the proliferative defect caused by PLA2G4A ablation. Upstream, we identify SP1 as a candidate transcriptional regulator of PLA2G4A. Collectively, these findings suggest a linear SP1/PLA2G4A/IL-1β/MAPK/HSF1 signaling axis that operates cell-intrinsically to promote NSCLC proliferation, survival, and metastasis. Targeting this pathway may represent a potential therapeutic avenue for NSCLC.
Environmental stressors challenge cellular homeostasis, yet how they corrupt proteostasis to drive tissue injury remains incompletely defined. Here, we report that aberrant accumulation of disulfide-crosslinked proteins, a hallmark of disulfide stress, acts as a novel, actionable molecular lesion in ultraviolet B (UVB)-induced skin photodamage and photoaging. This lesion executes disulfidptosis, a recently discovered form of regulated cell death. We demonstrate that disulfide stress acts as a quantifiable pathogenic continuum, linking acute UVB insult to chronic tissue degeneration in skin. Core biochemical features of disulfidptosis, including NADPH depletion, excessive disulfide-bond formation, and F-actin collapse, were consistently observed in human keratinocytes from physiologically relevant systems: sun-exposed skin, ex vivo UVB-irradiated skin, and keratinocytes cultured in vitro. Genetic and pharmacological interrogation across murine models of chronic and acute injury established NCKAP1 as an essential mediator and revealed that inhibition of this pathway (via the reducing agent TCEP) robustly mitigates keratinocyte death and tissue damage. Our work defines UVB-induced disulfide stress and NCKAP1-mediated disulfidptosis as a previously unrecognized proteotoxic axis in environmental skin disease. We posit that disulfide-bond dyshomeostasis may represent a targetable vulnerability in a range of age-related and environmental pathologies characterized by proteostasis collapse, offering a new paradigm for therapeutic intervention beyond dermatology.
Diabetic vasculopathy represents one of the most serious complications of type 2 diabetes mellitus (T2DM). Growing evidence suggests that its pathogenesis is closely linked to chronic inflammation-driven phenotypic switching of vascular smooth muscle cells (VSMCs), which under hyperglycemic conditions exhibit heightened proliferative and migratory activity. While hydrogen sulfide (H₂S) is known for its antioxidant and anti-inflammatory roles in diabetic vasculopathy, the specific mechanisms by which H₂S alleviates these abnormal VSMCs phenotypes in T2DM remain unclear. Using T2DM mice and mouse aortic vascular smooth muscle cells (MOVAS) cultured under high-glucose-high-fat (HGHF) conditions, we observed a marked decrease in both the expression of the H₂S-synthesizing enzyme cystathionine γ-lyase (CSE) and endogenous H₂S production. These changes were accompanied by elevated oxidative stress, activation of the NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, and enhanced MOVAS proliferation and migration. Notably, the H₂S donor NaHS reversed these changes. Further investigation into protein S-sulfhydration revealed that H₂S promotes the S-sulfhydration of thioredoxin reductase 1 (TrxR1). Through pharmacological inhibition and rescue experiments, we demonstrated that H₂S mediates S-sulfhydration at the Cys611 residue of TrxR1, thereby regulating its enzymatic activity and influencing the thioredoxin 1 (Trx1)–thioredoxin-interacting protein (TXNIP)–NLRP3 signaling axis. This process leads to suppression of inflammasome activation and contributes to the antioxidant, anti-inflammatory, anti-migratory, and anti-proliferative effects observed in MOVAS. Our study reveals a novel pathway whereby H₂S alleviates diabetic vascular complications via TrxR1 S-sulfhydration at Cys611 and subsequent inhibition of the Trx1–TXNIP–NLRP3 axis, highlighting a promising therapeutic target.
Patients with Alzheimer’s disease (AD) exhibit reduced cerebral venous oxygen saturation, that progresses with disease severity and correlates with cognitive decline. The underlying causes of this hypoxia, however, remain unclear. The accumulation of beta-amyloid (Aβ42) and its pathological isoform with isomerized Asp7 (isoAβ42) in the brain are the key pathological factors in AD. Given that red blood cells (RBCs) are the primary carrier of Aβ in the bloodstream and their loading with Aβ42 increases with age and AD, we studied whether Aβ42 and isoAβ42 binding affects human RBC oxygen transport. Here, we demonstrate for the first time that elevated beta-amyloids binding to RBCs reduces hemoglobin oxygen affinity and slows down the rate of oxygen release. This reduction of hemoglobin oxygen affinity is caused by a decrease in the level of reactive oxygen species (ROS). As a result, Aβ42 binding decreases hemoglobin glutathionylation and its alpha-helical content, whereas isoAβ42 reduces NO level and alters heme-state of hemoglobin. Importantly, inhibition of NADPH oxidase abolishes the impact of Aβ on ROS, oxygen affinity and alpha-helical content. Therefore, we propose that beta-amyloids impair erythrocyte oxygen affinity primarily through the suppression of NADPH oxidase activity. Moreover, we found a negative correlation between the Aβ42 amount on the surface of RBCs and the level of intracellular ROS in transgenic APP/PS1-mouse model of AD. The study reveals a new role for Aβ42 in the regulation of Hb-O₂-affinity and O₂-release from RBCs, raising the possibility of one mechanism underlying the reduced blood oxygen saturation reported in Alzheimer’s disease.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with poor patient outcomes due to development of tumor cell drug resistance impacting treatment efficacy. Shifts in tumor cell transcriptional subtypes from well-differentiated classical to poorly differentiated basal-like cells can drive PDAC chemotherapeutic resistance. Such transcriptomic changes have been linked to cellular metabolic states, but how coordination of transcriptional and metabolic programs is mediated at the molecular level remains unclear. The stress-responsive long noncoding RNA NEAT1, an essential constituent of nuclear condensates called paraspeckles, has been associated with classical PDAC and was previously linked to regulation of cellular metabolism. In this study, we utilized a high-throughput drug screening approach in NEAT1-deficient cancer cells to uncover functional metabolic targets in these cells, identifying ferroptosis via GPX4 inhibition as a major vulnerability of cells lacking paraspeckles. We find that the paraspeckle-forming isoform of NEAT1 is central to ferroptosis suppression, and we extend these results into PDAC cell line models with genetic suppression or activation of NEAT1. We find that NEAT1-nucleated paraspeckles underlie the expression program tied to the classical PDAC subtype and promote ferroptosis resistance. We pinpoint the paraspeckle-suppressive RNA-binding protein QKI, associated with basal-like PDAC, as a positive regulator of ferroptosis susceptibility, possibly through its suppression of paraspeckles. These results link NEAT1 and regulation of paraspeckle condensates to subtype-specific ferroptosis susceptibility in PDAC and offer novel avenues for targeting metabolic vulnerabilities of pancreatic cancer cells on the basis of transcriptional subtype.
