BACKGROUNDAbnormal glycolysis and lipid metabolism play important roles in the occurrence and development of gastric cancer (GC). Moreover, dysregulation of circadian genes is associated with metabolic reprogramming in the tumor microenvironment. This study aimed to determine the role of retinoic acid-related orphan receptor alpha (RORα) in glucose and lipid reprogramming in GC.METHODSThe effects on cell proliferation and chemoresistance in vitro and in vivo were studied using gain- and loss-of-function experiments. Glycolytic activity and lipid synthesis were assessed using a Seahorse assay and reagent kits. Moreover, the regulatory mechanisms were explored using half-life, coimmunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), luciferase reporter and immunofluorescence colocalization assays in GC cells. In addition, the relationships of RORα with E47 and AKR1A1 were analyzed using public databases and retrospective clinicopathological analyses.RESULTSRORα deletion promoted cell proliferation and fluorouracil (5-FU) chemoresistance by increasing glycolytic activity and lipid synthesis. In contrast, SR1078, an RORα activator, reversed these changes and had a synergistic inhibitory effect on cell proliferation in combination with 2-deoxygulose glucose (2-DG) or atorvastatin. Mechanistically, aldo-keto reductase family 1 member A1 (AKR1A1), is the key driver of RORα-mediated glucose and lipid reprogramming. Specifically, E47 is an AKR1A1 transcription factor, and its stability is affected by β-catenin. RORα deletion indirectly promoted E47 protein stability through the up-regulation of β-catenin, leading to increased AKR1A1 transcriptional activity. Moreover, RORα, E47 and AKR1A1 expression was dysregulated, and associated with clinicopathological parameters and prognosis in patients with GC. These expression patterns including RORα-low, E47-high and AKR1A1-high expression patterns alone or in combination were correlated with reduced responsiveness, poor prognosis, increased standard uptake value (SUV) levels and lipid droplet formation.CONCLUSIONSThese findings reveal a novel mechanism by which RORα regulates glucose and lipid reprogramming and may be a promising target for GC treatment.

2025-01-01·Journal of Molecular Biology

AlkA Glycosylase and AlkB Dioxygenase Constitute an Effective Protective System for Endogenously Arising Acrolein

Article

作者: Dylewska, Małgorzata ; Poznański, Jarosław ; Sokołowska, Beata ; Ćwiek, Karolina ; Mielecki, Damian ; Maciejewska, Agnieszka M ; Padoł, Katarzyna ; Dąbrowska, Izabela

Acrolein (ACR) is a ubiquitous environmental pollutant but also formed endogenously as a metabolite in oxidative stress conditions. Its adduct to adenine 1,N⁶-α-hydroxypropanoadenine (HPA) is a mutagenic lesion effectively repaired by the AlkB dioxygenase. Here, we provide in vivo, in vitro, and in silico evidence that it is also the substrate for the AlkA glycosylase. We studied the role of AlkA and AlkB in E. coli cells under conditions of induced adaptive response. Both alkA and alkB defective strains were not more sensitive to exogenous ACR than the wild type was. To simulate endogenously arising adducts, we used acrolein-modified plasmids, allowing monitoring of all kinds of substitutions originating from the acrolein modification of adenine. Both the AlkA and AlkB proteins were engaged in alleviating HPA-induced mutagenesis. Moreover, HPA was effectively repaired by AlkA and AlkB in vivo, even without induction of adaptive response. These findings suggest that the main contribution to acrolein mutagenicity comes from its endogenous sources, whereas AlkA and AlkB can play an additional role in controlling the level of DNA adducts of endogenous origin. Acrolein does not induce the adaptive response. HPA contains an asymmetric carbon atom in the hydroxypropano ring and exists as two stereoisomers. AlkA excises both of them in vitro. Molecular modelling demonstrated how dsDNA carrying both HPA stereoisomers could be properly bound at the AlkA catalytic centre. So, in contrast to the reaction catalyzed by AlkB, the HPA repair by AlkA is not expected to be stereoselective.

2024-12-01·Poultry Science

Melatonin nuclear receptors mediate monochromatic light-induced T-lymphocyte proliferation of thymus through the AKT/GSK3β/β-catenin pathway in chick

Article

作者: Chen, Yaoxing ; Cao, Jing ; Xiong, Juanjuan ; Wang, Zixu ; Dong, Yulan

Based on previous research, it's unclear about the signaling pathway involved in the negative regulation of T-lymphocyte proliferation in thymus by monochromatic red light. Newly hatched chicks were randomly assigned divided into white (WL), red (RL), green (GL), and blue (BL) light treatments. Three days later, each light treatment group was further divided into intact, sham operation, and pinealectomy groups. The findings revealed that RL led to an increase in the expression of RORα and RORγ, while p-AKT/p-GSK3β/β-catenin/CyclinD1 expression in the thymus of chicks were decreased. Conversely, GL showed opposite results compared to RL. After pinealectomy, accompanied with the expression of RORα and RORγ increased under four light, p-AKT/ p-GSK3β/ β-catenin/ CyclinD1 expression were decreased. In vitro, exogenous melatonin increased the p-AKT/β-catenin/CyclinD1 expression in the thymic lymphocytes of chick reared under RL. The stimulative effect of melatonin was enhanced by SR3335 (RORα antagonist) or GSK298 (RORγ antagonist), while it was attenuated by SR1078 (RORα/RORγ agonist), LY-294 (PI3K antagonist) and HY-102 (AKT antagonist). These results demonstrate that RORα/RORγ negatively regulate monochromatic red light induced-T-lymphocyte proliferation in the thymus, possibly through the PI3K/AKT/p-GSK3β (Ser9) signaling pathway.

100 项与 SR-1078 相关的药物交易

登录后查看更多信息