Inhibition of KDM4A restricts SQLE transcription and induces oxidative stress imbalance to suppress bladder cancer

The duality of GSK-3β in urinary bladder cancer: Tumor suppressor and promoter roles through multiple signaling pathways

Urinary bladder cancer (UBC), the tenth most common cancer globally, is primarily categorized into non-muscle-invasive (NMIBC) and muscle-invasive (MIBC) types. NMIBC has a low risk of metastasis but tends to recur frequently after transurethral resection, whereas MIBC is associated with a higher likelihood of metastasis and poorer prognosis. At diagnosis, roughly 75 % of UBC patients have NMIBC, while the remaining 25 % present with tumor invasion into the bladder's muscle layer. The molecular complexity of UBC has driven research toward identifying subtypes for more personalized treatment approaches. Glycogen synthase kinase-3β (GSK-3β) has emerged as a pivotal regulator in UBC through its dual roles across six key pathways: (1) Wnt/β-catenin regulation (tumor suppression vs oncogenic activation), (2) ER stress responses (apoptosis induction vs cytoprotection), (3) Akt/GSK-3β/β-catenin/c-Myc signaling, (4) PI3K/Akt/mTOR interactions, (5) NF-κB-mediated immune modulation, and (6) Snail1/β-catenin-driven epithelial mesenchymal transition (EMT). Our analysis reveals that GSK-3β's context-dependent functions create both therapeutic opportunities and challenges - while inhibition suppresses tumor growth via β-catenin degradation, it may simultaneously activate NF-κB-mediated oncogenic processes. These paradoxical effects are particularly evident in the tumor microenvironment, where GSK-3β modulation differentially regulates CD8+ T cell function and macrophage polarization. Understanding these complex pathway interactions is crucial for developing precision therapies that exploit GSK-3β's tumor-suppressive roles while mitigating its oncogenic potential.

Multidimensional insights into squalene epoxidase drug development: in vitro mechanisms, in silico modeling, and in vivo implications

INTRODUCTION

Squalene epoxidase (SQLE) is a pivotal enzyme in sterol biosynthesis, catalyzing the conversion of squalene to 2,3-oxidosqualene. Beyond its core role in cholesterol homeostasis, SQLE is implicated in cancer, hypercholesterolemia, and fungal infections, positioning it as a valuable therapeutic target.

AREAS COVERED

We conducted a comprehensive literature search across primary databases to gather in vitro, in silico, and in vivo evidence on SQLE. This review explores the enzyme's structural and functional features, including substrate specificity and catalytic mechanisms, and examines inhibitor interactions. Computational methods predict enzyme - inhibitor dynamics, guiding drug design, while in vivo investigations clarify SQLE's role in metabolic disorders and tumorigenesis. Challenges include drug resistance and study discrepancies, but emerging technologies, such as cryo-electron microscopy and CRISPR editing, offer new avenues for deeper exploration.

EXPERT OPINION

SQLE is an underexplored yet promising therapeutic target, with particular relevance to oxidative stress, ferroptosis, and gut microbiota research. Overcoming current barriers through advanced technologies and multidisciplinary strategies could propel SQLE-targeted treatments into clinical practice, supporting precision medicine and broader translational applications.

Disturbing Cholesterol/Sphingolipid Metabolism by Squalene Epoxidase Arises Crizotinib Hepatotoxicity

Metabolic disorders have been identified as one of the causes of drug-induced liver injury; however, the direct regulatory mechanism regarding this disorder has not yet been clarified. In this study, a single regulatory mechanism of small molecule kinase inhibitors, with crizotinib as the representative drug is elucidated. First, it is discovered that crizotinib induced aberrant lipid metabolism and apoptosis in the liver. A mechanistic study revealed that crizotinib treatment promoted the accumulation of squalene epoxidase (SQLE) by inhibiting autophagosome-lysosome fusion which blocked the autophagic degradation of SQLE. A maladaptive increase in SQLE led to disturbances in cholesterol and sphingolipid metabolism via an enzymatic activity-dependent manner. Abnormal cholesterol results in both steatosis and inflammatory infiltration, and disturbances in sphingolipid metabolism promote cell apoptosis by inducing lysosomal membrane permeabilization. The restoration of the level or activity of SQLE ameliorated steatosis and hepatocyte injury. The autophagy activator known as metformin or the SQLE enzymatic inhibitor known as terbinafine has potential clinical use for alleviating crizotinib hepatotoxicity.

Ferroptosis: iron release mechanisms in the bioenergetic process

Ferroptosis, an iron-dependent form of cell death, has been the focus of extensive research over the past decade, leading to the elucidation of key molecules and mechanisms involved in this process. While several studies have highlighted iron sources for the Fenton reaction, the predominant mechanism for iron release in ferroptosis has been identified as ferritinophagy, which occurs in response to iron starvation. However, much of the existing literature has concentrated on lipid peroxidation rather than on the mechanisms of iron release. This review proposes three distinct mechanisms of iron mobilization: ferritinophagy, reductive pathways with selective gating of ferritin pores, and quinone-mediated iron mobilization. Notably, the latter two mechanisms operate independently of iron starvation and rely primarily on reductants such as NADH and O2•-. The inhibition of the respiratory chain, particularly under the activation of α-ketoglutarate dehydrogenase, leads to the accumulation of these reductants, which in turn promotes iron release from ferritin and indirectly inhibits AMP-activated protein kinase through excessive iron levels. In this work, we delineate the intricate relationship between iron mobilization and bioenergetic processes under conditions of oxidative stress. Furthermore, this review aims to enhance the understanding of the connections between ferroptosis and these mechanisms.