1-Bromopropane-induced apoptosis in OVCAR-3 cells via oxidative stress and inactivation of Nrf2

m6A methylation modification: Potential pathways to suppress osteosarcoma metastasis

Osteosarcoma is a highly aggressive malignant bone tumor prone to metastasis, and its metastatic process is one of the main reasons for treatment failure and poor prognosis. Recent studies have demonstrated that modification of m6A methylation plays an important role in osteosarcoma metastasis, influencing both invasion and metastasis through various signaling pathways. Therefore, clarification of the specific effects of m6A methylation modification in osteosarcoma may reveal ways to improve the prognosis of osteosarcoma patients. The roles of various components involved in the m6A methylation modification process in osteosarcoma have been investigated, with studies focusing more on their effects than on their mechanisms. In this review, we focus on the interactions between the "writers," "erasers," and "readers" of m6A methylation and tumor metastasis-related factors to enhance the understanding of osteosarcoma and m6A methylation modification, with the aim of identifying clinical diagnostic biomarkers and potential therapeutic targets for osteosarcoma metastasis.

1-Bromopropane induces mitochondrial damage and lipid metabolism imbalance in respiratory epithelial cells through the PGC-1α/PPARα pathway

1-Bromopropane (1-BP) has become a new air pollutant in occupational and living environments due to its advantages in industrial applications and as a representative compound of volatile organic compounds (VOCs). As an irritant, its damaging effects on respiratory epithelium are worthy of further study. This study aimed to explore the damage effects of 1-BP on respiratory epithelial cells and reveal its underlying mechanisms. We found that exposure to 1-BP markedly reduced the viability of respiratory epithelial cells in a dose-dependent manner, and induced oxidative stress and vacuolation changes in respiratory epithelial cells. Subsequently, through RNA-seq analysis, we identified that the 1-BP-induced damage of respiratory epithelial cells was related to the mitochondrial function pathway and further verified that 1-BP caused mitochondrial damage of respiratory epithelial cells, which was manifested as ultrastructural damage, decreased membrane potential, ATP, and MFN2 levels. These damages were associated with cellular oxidative stress responses. Pretreating cells with the agonists of PGC-1α and PPARα, we revealed that 1-BP affected the expression of PGC-1α and interfered with its coactivator PPARα levels, causing an increase in the expression of lipid-producing genes and a decrease in the expression of lipid-decomposing genes, thus leading to a lipid accumulation in respiratory epithelial cells. Meanwhile, the imbalance of lipid metabolism in respiratory epithelial cells induced by 1-BP further caused mitochondrial damage, and the effect was bidirectional. These findings suggested that 1-BP has a potential role in inducing respiratory epithelial cell damage and is associated with the PGC-1α/PPARα signaling pathway.

Induced oxidative stress and apoptosis by 1-bromopropane in SH-SY5Y cells correlates with inhibition of Nrf2 function

In this study, we established SH-SY5Y human neuroblastoma cells as an in vitro model to investigate whether oxidative stress and the nuclear erythroid-2 related factor 2 (Nrf2) signaling pathway are associated with 1-bromopropane (1-BP) -induced nerve cell injury. We identified that 1-BP exhibited neurotoxicity mainly through oxidant-based processes in SH-SY5Y cells, as reactive oxygen species, malondialdehyde levels, and 8-hydroxy-2' -deoxyguanosine significantly increased, while superoxide dismutase activity decreased. Furthermore, Nrf2 translocation from the cytosol to the nucleus was inhibited, as was downstream protein expression of the Nrf2-regulated genes HO-1 and Bcl-2. Activation of caspase-9 and -3 increased, and apoptosis was observed. Vitamin C alleviated 1-BP-induced apoptosis by decreasing oxidative stress and activating the Nrf2 signaling pathway. Knockdown of Nrf2 in SH-SY5Y cells increased 1-BP-induced reactive oxygen species production and cell apoptosis, and inhibited HO-1 and Bcl-2 protein expression, while overexpression of Nrf2 alleviated these processes. These findings suggest that 1-BP-induced oxidative stress and apoptosis in SH-SY5Y cells are associated with Nrf2 function inhibition.

Hypoxia inducible factor-1ɑ as a potential therapeutic target for osteosarcoma metastasis

Osteosarcoma (OS) is a malignant tumor originating from mesenchymal tissue. Pulmonary metastasis is usually present upon initial diagnosis, and metastasis is the primary factor affecting the poor prognosis of patients with OS. Current research shows that the ability to regulate the cellular microenvironment is essential for preventing the distant metastasis of OS, and anoxic microenvironments are important features of solid tumors. During hypoxia, hypoxia-inducible factor-1α (HIF-1α) expression levels and stability increase. Increased HIF-1α promotes tumor vascular remodeling, epithelial-mesenchymal transformation (EMT), and OS cells invasiveness; this leads to distant metastasis of OS cells. HIF-1α plays an essential role in the mechanisms of OS metastasis. In order to develop precise prognostic indicators and potential therapeutic targets for OS treatment, this review examines the molecular mechanisms of HIF-1α in the distant metastasis of OS cells; the signal transduction pathways mediated by HIF-1α are also discussed.

Sodium selenite (Na2SeO3) attenuates T-2 toxin-induced iron death in LMH cells through the ROS/PI3K/AKT/Nrf2 pathway

T-2 toxin, is a monotrichous mycotoxin commonly found in animal feed and agricultural products that can damage tissues and organs through oxidative stress. Selenium is a trace element with favorable antioxidant effects. However, it is unclear whether T-2 toxin-induces ferroptosis in LMH cells and whether Na2SeO3 has a protective role in this process. To investigate the process of hepatic injury by T-2 toxin and its antagonistic effect by Na2SeO3, we used 20 ng/mL T-2 toxin as well as 160 nmol/L Na2SeO3 to treat the LMH cells. The results demonstrated that exposure to the T-2 toxin induced iron death by increasing the quantity of ROS, leading to oxidative damage, decreasing the quantities of SOD, GPx, and T-AOC, and increasing the accumulation of MDA and H2O2, which resulted in the accumulation of Fe2+ and the down-regulation of the manifestation of linked genes and proteins including FTH1, Gpx4, NQO-1, and HO-1. After the addition of Na2SeO3, the PI3K/AKT/Nrf2 pathway is activated by regulating the selenoproteins gene level, and the above abnormal changes are reversed. In summary, Na2SeO3 alleviated T-2 toxin-induced iron death via the PI3K/AKT/Nrf2 pathway. These study not only broaden the cytotoxic knowledge regarding T-2 toxin, but also serve as a foundation for the use of Na2SeO3 in daily life.

Role of the Nrf2 Signaling Pathway in Ovarian Aging: Potential Mechanism and Protective Strategies

The ovary holds a significant role as a reproductive endocrine organ in women, and its aging process bears implications such as menopause, decreased fertility, and long-term health risks including osteoporosis, cardiovascular disorders, and cognitive decline. The phenomenon of oxidative stress is tightly linked to the aging metabolic processes. More and more studies have demonstrated that oxidative stress impacts both physiologic and pathologic ovarian aging, and the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway plays a crucial role in regulating the antioxidant response. Furthermore, various therapeutic approaches have been identified to ameliorate ovarian aging by modulating the Nrf2 pathway. This review summarizes the important role of the Nrf2/ Kelch-like ECH-associated protein 1 (Keap1) signaling pathway in regulating oxidative stress and influencing ovarian aging. Additionally, it highlights the therapeutic strategies aimed at targeting the Nrf2/Keap1 pathway.

Cross-sectional and longitudinal relationships between urinary 1-bromopropane metabolite and pulmonary function and underlying role of oxidative damage among urban adults in the Wuhan-Zhuhai cohort in China

1-bromopropane is a US Environmental Protection Agency-identified significant hazardous air pollutant with concerned adverse respiratory effect. We aimed to investigate the relationship between 1-bromopropane exposure and pulmonary function and the underlying role of oxidative damage, which all remain unknown. Pulmonary function and urinary biomarkers of 1-bromopropane exposure (N-Acetyl-S-(n-propyl)-L-cysteine, BPMA) and oxidative damage to DNA (8-hydroxy-deoxyguanosine, 8-OHdG) and lipid (8-iso-prostaglandin-F2α, 8-iso-PGF2α) were measured for 3259 Chinese urban adults from the Wuhan-Zhuhai cohort. The cross-sectional relationship of BPMA with pulmonary function and the joint relationship of BPMA and 8-OHdG or 8-iso-PGF2α with pulmonary function were investigated by linear mixed models. The mediating roles of 8-OHdG and 8-iso-PGF2α were evaluated by mediation analysis. Additionally, a panel of 138 subjects was randomly convened from the same cohort to evaluate the stability of BPMA repeatedly measured in urine samples collected over consecutive three days and intervals of one, two, and three years, and to estimate the longitudinal relationship of BPMA with pulmonary function change in three years. We found each 3-fold increase in BPMA was cross-sectionally related to FVC and FEV₁ reductions by 29.88-mL and 25.67-mL, respectively (all P < 0.05). Joint relationship of BPMA and 8-OHdG rather than 8-iso-PGF2α with reduced pulmonary function was observed. Moreover, 8-OHdG significantly mediated 9.44% of the BPMA-related FVC reduction. Findings from the panel revealed a fair to excellent stability (intraclass correlation coefficient: 0.43-0.79) of BPMA in repeated urines collected over a period of three years. Besides, BPMA was longitudinally related to pulmonary function reduction in three years: compared with subjects with persistently low BPMA level, those with persistently high BPMA level had 79.08-mL/year and 49.80-mL/year declines in FVC and FEV₁, respectively (all P < 0.05). Conclusively, 1-bromopropane exposure might impair pulmonary function of urban adult population, and oxidative DNA damage might be a potential mechanism underlying 1-bromopropane impairing pulmonary function especially FVC.

Role of NRF2 in Ovarian Cancer

Among gynaecologic malignancies, ovarian cancer is one of the most dangerous, with a high fatality rate and relapse due to the occurrence of chemoresistance. Many researchers demonstrated that oxidative stress is involved in tumour occurrence, growth and development. Nuclear factor erythroid 2-related factor 2 (NRF2) is an important transcription factor, playing an important role in protecting against oxidative damage. Increased levels of Reactive Oxygen Species (ROS) activate NRF2 signalling, inducing the expression of antioxidant enzymes, such as haem oxygenase (HO-1), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD), that protect cells against oxidative stress. However, NRF2 activation in cancer cells is responsible for the development of chemoresistance, inactivating drug-mediated oxidative stress that normally leads to cancer cells’ death. In this review, we report evidence from the literature describing the effect of NRF2 on ovarian cancer, with a focus on its function in drug resistance, NRF2 natural and synthetic modulators and its protective function in normal ovarian preservation.