TDZD-8

To investigate the regulatory role of NANOG in genes associated with stemness, symmetric division, and therapeutic resistance in colorectal cancer stem-like cells (CRC-SCs), with a focus on ERK/GSK-3β/β-catenin signalling and epithelial-mesenchymal transition (EMT), in order to evaluate the translational potential of targeting NANOG-associated signalling pathways.

Stemness, signalling activity, and cell division modes were analysed using 3D colonospheres enriched for CRC-SCs. Drug responses to the MEK inhibitor U0126 and the GSK-3β inhibitor TDZD-8 were assessed in CRC patient-derived organoids (PDOs), alongside molecular assays, immunohistochemistry with H-score quantification in xenograft models, and molecular dynamics simulations.

NANOG overexpression enhanced the expression of stemness-associated genes, promoted symmetric cell division, and activated ERK/GSK-3β signalling, contributing to increased sphere formation. Inhibition of MEK and GSK-3β reduced EMT, cell proliferation, and symmetric division in CRC-SCs. NANOG-mediated dysregulation of ERK/GSK-3β altered β-catenin signalling and disrupted E-cadherin-dependent cell-cell adhesion. Molecular simulations and drug assays demonstrated that TDZD-8 and U0126 interfere with NANOG-DNA binding and β-catenin/E-cadherin interactions.

NANOG drives CRC-SC maintenance via ERK/GSK-3β/β-catenin signalling and EMT modulation. This study offers significant insights into the translational impact of targeting NANOG and its downstream pathways with small-molecule inhibitors U0126 and TDZD-8 and presents a promising strategy to reduce CRC-SCs stemness, functionality, and tumourigenicity.

Background: Recent studies have shown that fine particulate matter (PM2.5) exposure is a key harmful risk factor for chronic obstructive pulmonary disease (COPD) and PM2.5-associated ferroptosis plays an important role during the process of airway oxidative stress. Our preliminary study revealed that PM2.5 reduces the expression of phosphorylated glycogen synthase kinase (GSK)-3β in airway epithelial cells, the overactivity of the GSK-3β/Nuclear Factor erythroid 2-Related Factor 2 (NRF2) pathway is related to ferroptosis. Accordingly, we explored whether PM2.5 could induce ferroptosis in airway epithelial cells and promote the development of COPD via the GSK-3β/NRF2 pathway. Methods: The effect of GSK-3β/NRF2-mediated ferroptosis was assessed using an in vivo model of 20 μg/μl PM2.5-induced COPD by tracheal infusion and 50 μg/ml PM2.5-exposed airway epithelial cells in vitro. Then we performed qRT-PCR to detect mRNA expression; Western blotting, immunofluorescence and immunohistochemical staining to detect protein expression; flow cytometry and spectrophotometry to measure the levels of intracellular lipid peroxidation; small animal spirometry to examine the lung function in mouse, and hematoxylin and eosin (H&E) staining to measure the average alveolar septa in mouse lung sections. Results: We found that PM2.5 decreased the ferroptosis marker mRNA expression of NRF2, SLC7A11 and GPX4, and also decreased the protein expression of p-GSK-3β, NRF2, SLC7A11 and FTH-1, increased the protein expression of NCOA4, then increased the level of lipid peroxidation and MDA in human airway epithelial cells. Further, PM2.5 reduced the expression of p-GSK-3β, NRF2, SLC7A11 and GPX4 in the lungs, subsequently induced lung injury and impaired lung function of mice. Treatment with ferroptosis inhibitors FER-1 and GSK-3β inhibitor TDZD-8 reversed this effect. Conclusion: Our findings suggested that PM2.5 induced ferroptosis of airway epithelial cells, contributing to airway oxidative stress via the GSK-3β/NRF2 signaling pathway in vivo and in vitro, which could be a therapeutic target for PM2.5-induced COPD.