Lung cancer is among the most clinically challenging tumors because of its aggressive proliferation, metastasis, and the presence of cancer stem cells (CSCs). Natural bioactive substances have been used for cancer prevention, and, in particular, resveratrol (RSV), a stilbene-based compound with wide biological properties, has been proposed for chemoprevention. Its lesser-known analogue 4,4’-dihydroxy-trans-stilbene (DHS) has demonstrated superior activity both in cell-based assays and in mouse and zebrafish in vivo models. The present study analyzed the effects of DHS and RSV on A549 lung cancer cells, with a particular focus on stemness features and CSCs, isolated by sorting of the side population (SP). The results show that both stilbenes, especially DHS, strongly inhibited cell cycle progression. A reduction in the S phase was induced by DHS, whereas an increase in this phase was obtained with RSV. In addition, 50% reductions in the clonogenicity and soft agar colony formation were observed with the DHS treatment only. Finally, both stilbenes, especially DHS, reduced stemness marker expression in A549 cells and their sorted SP fraction. Spheroid formation, higher in SP cells than in the main population (MP), was significantly reduced after pretreatment with DHS, which was found to decrease SOX2 levels more than RSV. These findings indicate that stilbenes, and particularly DHS, affect stemness features of A549 cells and the SP fraction, suggesting their potential utility as anticancer agents, either alone or combined with chemotherapeutic drugs.

Sigma1 receptor (S1R) and some aquaporins (AQPs) are involved in controlling oxidative stress, but only recently has their possible interaction emerged. S1R acts by interacting with proteins in the plasma membrane and organelles and AQPs by favoring the hydrogen peroxide (H₂O₂) cell removal. To date, the possible regulation of peroxiporins by S1R has not been explored. Using H₂O₂ HyPer7 biosensors and knockdown techniques, we investigated (1) the AQPs and S1R functional involvement in H₂O₂ diffusion through the plasma membrane and in the outer and inner mitochondrial membranes, and (2) the possible interaction between S1R and AQPs. Our data showed the functional involvement of different AQPs in the diffusion of H₂O₂: AQP3, AQP6, and AQP8 in the plasma membrane; AQP6 in the outer mitochondrial membrane; and AQP6 and AQP8 in the inner mitochondrial membrane. The knockdown of S1R demonstrated its involvement in the overall diffusion of H₂O₂ across the three compartments. The double knockdown of S1R and a single AQP indicated that AQP8 and AQP6 could be regulated by S1R. These findings demonstrate the coordinated role of AQPs in the mitochondria and the plasma membranes and that S1R modulates the AQP-facilitated H₂O₂ cell removal, thus controlling the oxidative status and, most likely, the oxidative stress.

Cigarette smoke is a major inducer of oxidative stress, promoting reactive oxygen species (ROS) accumulation and contributing to the pathogenesis of chronic obstructive pulmonary disease (COPD) and lung cancer. Heated tobacco products (HTP) and e-cigarettes are promoted as reduced-risk alternatives; however, their impact on cellular redox regulation remains unclear. Here, we investigated the effects of conventional cigarette smoke extract (CSE), HTP, and e-cigarette extracts on hydrogen peroxide (H₂O₂) permeability mediated by aquaporins (peroxiporins) and on the activity of key antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase) in ATII-like cells. Eight aquaporins were detected at the mRNA level, and seven were confirmed at the protein level. CSE markedly inhibited H₂O₂ permeability across plasma, mitochondrial, and nuclear membranes. HTP extract impaired H₂O₂ transport across the plasma membrane and nuclear envelope, while mitochondrial permeability was preserved. Both CSE and HTP extract reduced superoxide dismutase and glutathione peroxidase activities. In contrast, e-cigarette extract exerted minimal effects on membrane H₂O₂ permeability and selectively decreased superoxide dismutase activity. Overall, our findings identify a graded pattern of oxidative toxicity (CSE > HTP > e-cigarette) and highlight peroxiporins as critical regulators of intracellular redox homeostasis. Although less harmful than cigarettes, alternative nicotine delivery systems are not biologically inert.