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Project description:Small cell lung cancer (SCLC) patients experience rapid disease progression despite frequently achieving a complete response to first-line therapy. Maintenance treatments, aiming at controlling residual tumor cells, generally fail due to cross-resistance, inability to target tumor vulnerabilities, or dose-limiting side effects. Here, we show that SCLC cells, like their cell-of-origin, pulmonary neuroendocrine cells (PNECs), exhibit notably low activity in pathways protecting against reactive oxygen species (ROS). When exposed to a novel thioredoxin reductase 1 (TXNRD1) inhibitor, these cells quickly exhaust their ROS-scavenging capacity, independent of their molecular subtype and the resistance status against first-line therapy. Importantly, SCLC cells, in contrast to non-cancerous cells, cannot adapt to drug-induced ROS stress because they repress ROS defense enzymes through multiple layers of epigenetic and transcriptional mechanisms. By exploiting this differential ability to manage oxidative stress, we demonstrate that the therapeutic dose of TXNRD1 inhibitors can be safely increased in vivo through pharmacological activation of the NRF2 stress response pathway using Bardoxolon-Methyl (CDDO-Me), leading to improved tumor control without added toxicity to healthy tissues. These findings underscore the therapeutic potential of TXNRD1 inhibitors in cancers like SCLC, which are marked by reduced ROS-scavenging capacity and strong suppression of adaptive resistance mechanisms.
2024-11-11 | GSE279100 | GEO
Project description:Small cell lung cancer (SCLC) patients experience rapid disease progression despite frequently achieving a complete response to first-line therapy. Maintenance treatments, aiming at controlling residual tumor cells, generally fail due to cross-resistance, inability to target tumor vulnerabilities, or dose-limiting side effects. Here, we show that SCLC cells, like their cell-of-origin, pulmonary neuroendocrine cells (PNECs), exhibit notably low activity in pathways protecting against reactive oxygen species (ROS). When exposed to a novel thioredoxin reductase 1 (TXNRD1) inhibitor, these cells quickly exhaust their ROS-scavenging capacity, independent of their molecular subtype and the resistance status against first-line therapy. Importantly, SCLC cells, in contrast to non-cancerous cells, cannot adapt to drug-induced ROS stress because they repress ROS defense enzymes through multiple layers of epigenetic and transcriptional mechanisms. By exploiting this differential ability to manage oxidative stress, we demonstrate that the therapeutic dose of TXNRD1 inhibitors can be safely increased in vivo through pharmacological activation of the NRF2 stress response pathway using Bardoxolon-Methyl (CDDO-Me), leading to improved tumor control without added toxicity to healthy tissues. These findings underscore the therapeutic potential of TXNRD1 inhibitors in cancers like SCLC, which are marked by reduced ROS-scavenging capacity and strong suppression of adaptive resistance mechanisms.
2024-11-11 | GSE280642 | GEO
Project description:Differential KEAP1/NRF2-mediated signaling widens the therapeutic window of redox-targeting drugs in SCLC therapy
| PRJNA1179864 | ENA
Project description:Differential KEAP1/NRF2-mediated signaling widens the therapeutic window of redox-targeting drugs in SCLC therapy [array]
| PRJNA1179876 | ENA
Project description:Differential KEAP1/NRF2-mediated signaling widens the therapeutic window of redox-targeting drugs in SCLC therapy [seq]
| PRJNA1170853 | ENA
Project description: Not available
| S-EPMC5733327 | biostudies-literature
Project description:Nuclear factor E2-related factor 2 (Nrf2) is a key transcription factor that regulates the expression of a number of antioxidant and detoxifying genes that provide cellular protection against various stressors including reactive oxygen species (ROS). Nrf2 activity is tightly regulated by a cytoplasmic inhibitory protein called Kelch-like ECH-associated protein 1 (Keap1). The mechanism that controls Keap1 expression, however, remains poorly understood. In the present study, we demonstrate that microRNA-7 (miR-7), which is highly expressed in the brain, represses Keap1 expression by targeting the 3'-untranslated region (UTR) of its mRNA in human neuroblastoma cells, SH-SY5Y. Subsequently, this event results in an increased Nrf2 activity, as evidenced by an increase in the expression of its transcriptional targets, heme oxygenase 1 (HO-1) and glutamate-cysteine ligase modifier subunit (GCLM), and an enhanced nuclear localization of Nrf2. In addition, miR-7 decreases the intracellular hydroperoxides level and increases the level of reduced form of glutathione, indicative of oxidative stress relief. We also demonstrate that targeted repression of Keap1 and activation of Nrf2 pathway, in part, underlies the protective effects of miR-7 against 1-methyl-4-phenylpyridinium (MPP+)-induced toxicity in SH-SY5Y and differentiated human neural progenitor cells, ReNcell VM. These findings point to a new mechanism by which miR-7 exerts cytoprotective effects by regulating the Nrf2 pathway.
| S-EPMC4684759 | biostudies-literature
Project description:In Drosophila, intestinal stem cells (ISCs) respond to oxidative challenges and inflammation by increasing proliferation rates. This phenotype is part of a regenerative response, but can lead to hyperproliferation and epithelial degeneration in the aging animal. Here we show that Nrf2, a master regulator of the cellular redox state, specifically controls the proliferative activity of ISCs, promoting intestinal homeostasis. We find that Nrf2 is constitutively active in ISCs and that repression of Nrf2 by its negative regulator Keap1 is required for ISC proliferation. We further show that Nrf2 and Keap1 exert this function in ISCs by regulating the intracellular redox balance. Accordingly, loss of Nrf2 in ISCs causes accumulation of reactive oxygen species and accelerates age-related degeneration of the intestinal epithelium. Our findings establish Keap1 and Nrf2 as a critical redox management system that regulates stem cell function in high-turnover tissues.
| S-EPMC3035938 | biostudies-literature
Project description:The molecular and cellular level reaches of the metabolic dysregulations that characterize diabetes are yet to be fully discovered. As mechanisms underlying management of reactive oxygen species (ROS) gain interest as crucial factors in cell integrity, questions arise about the role of redox cues in the regulation and maintenance of bone marrow-derived multipotent stromal cells (BMSCs) that contribute to wound healing, particularly in diabetes. Through comparison of BMSCs from wild-type and diabetic mice, with a known redox and metabolic disorder, we found that the cytoprotective nuclear factor erythroid-related factor 2 (Nrf2)/kelch-like erythroid cell-derived protein 1 (Keap1) pathway is dysregulated and functionally insufficient in diabetic BMSCs (dBMSCs). Nrf2 is basally active, but in chronic ROS, we found irregular inhibition of Nrf2 by Keap1, altered metabolism, and limited BMSC multipotency. Forced upregulation of Nrf2-directed transcription, through knockdown of Keap1, restores redox homeostasis. Normalized Nrf2/Keap1 signaling restores multipotent cell properties in dBMSCs through Sox2 expression. These restored BMSCs can resume their role in regenerative tissue repair and promote healing of diabetic wounds. Knowledge of diabetes and hyperglycemia-induced deficits in BMSC regulation, and strategies to reverse them, offers translational promise. Our study establishes Nrf2/Keap1 as a cytoprotective pathway, as well as a metabolic rheostat, that affects cell maintenance and differentiation switches in BMSCs.
| S-EPMC6302538 | biostudies-literature
Project description:Abnormal cancer antioxidant capacity is considered as a potential mechanism of tumor malignancy. Modulation of oxidative stress status is emerging as an anti-cancer treatment. Our previous studies have found that Nestin-knockdown cells were more sensitive to oxidative stress in non-small cell lung cancer (NSCLC). However, the molecular mechanism by which Nestin protects cells from oxidative damage remains unclear. Here, we identify a feedback loop between Nestin and Nrf2 maintaining the redox homeostasis. Mechanistically, the ESGE motif of Nestin interacts with the Kelch domain of Keap1 and competes with Nrf2 for Keap1 binding, leading to Nrf2 escaping from Keap1-mediated degradation, subsequently promoting antioxidant enzyme generation. Interestingly, we also map that the antioxidant response elements (AREs) in the Nestin promoter are responsible for its induction via Nrf2. Taken together, our results indicate that the Nestin-Keap1-Nrf2 axis regulates cellular redox homeostasis and confers oxidative stress resistance in NSCLC.
| S-EPMC6834667 | biostudies-literature