The pseudogene DUXAP10 contributes to gefitinib resistance in NSCLC by repressing OAS2 expression.

Gefitinib, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI),is the currently recommended first-line therapy for advanced EGFR-mutant lung cancer, and understanding the mechanism of resistance is the key to formulating therapeutic strategies for EGFR-TKIs. In this study, we evaluate the expression patterns and potential biological functions of the pseudogene DUXAP10 in gefitinib resistance. We find that pseudogene DUXAP10 expression is significantly upregulated in NSCLC gefitinib-resistant cells and tissues. Gain and loss of function assays reveal that knockdown of DUXAP10 by siRNA reverses gefitinib resistance both in vitro and in vivo. Furthermore, DUXAP10 interacts with the histone methyltransferase enhancer of zeste homolog 2 (EZH2) to repress the expression of 2',5'-oligoadenylate synthetase (OAS2). Overall, our study highlights the pivotal role of DUXAP10 in gefitinib resistance, and the DUXAP10/EZH2/OAS2 axis might be a promising therapeutic target to overcome acquired gefitinib resistance in NSCLC.

Inhibition on XBP1s-driven lipogenesis by Qushi Huayu Decoction contributes to amelioration of hepatic steatosis induced by fructose.

ETHNOPHARMACOLOGICAL RELEVANCE: Qushi Huayu Decoction (QHD) is a traditional Chinese medicine formula consisting of five herbs, which has been used for non-alcoholic fatty liver disease (NAFLD) treatment in clinic for decades in China and validated in several NAFLD animal models. The hepatic de novo lipogenesis (DNL) is enhanced greatly to contribute to steatosis in NAFLD. The spliced form of X-box binding protein 1 (XBP1s) initiates DNL independently of sterol regulatory element-binding protein (SREBP) and carbohydrate-responsive element-binding protein (ChREBP). AIM OF THE STUDY: To disclose the mechanism of inhibition on hepatic DNL by QHD and the responsible compounds. METHODS: The effects of QHD on hepatic DNL were evaluated in mice induced by high-fructose diet (HFru). The effects of the serum-absorbed compounds of QHD on XBP1s were evaluated in HepG2 cells induced by tunicamycin. Hepatic histology, triglyceride (TG) and nonesterified fatty acids were observed. Hepatic apolipoprotein B100 and very low-density lipoprotein were measured to reflect lipid out-transport. The mRNA expression of XBP1s and its target genes were detected by real-time polymerase chain reaction. The protein expression of TG synthetases and DNL enzymes, and inositol requirement enzyme 1 alpha (IRE1α), phosphorylated IRE1α and XBP1s were detected in liver tissue and HepG2 cells by western-blot. The binding activity of SREBP1, protein expression of ChREBP and XBP1s were detected in the nuclear extracts of liver tissue. RESULTS: Dynamical observing suggested feeding with HFru for 2 weeks was sufficient to induce hepatic lipogenesis and XBP1s. QHD ameliorated liver steatosis without enhancing out-transport of lipids, accompanied with more inhibitory effects on DNL enzymes than TG synthetases. QHD inhibits the nuclear XBP1s without affecting ChREBP and SREBP1. In QHD, chlorogenic acid, geniposide and polydatin inhibit lipogenesis initiated by XPB1s. CONCLUSION: QHD probably decreases hepatic DNL by inhibiting XBP1s independent of SREBP1 and ChREBP. Chlorogenic acid, geniposide and polydatin are the potential responsible compounds.

[Elucidation and Application of Novel Action of Therapeutic Agents for Diabetic Neuropathy].

Epalrestat is the only aldose reductase inhibitor that is currently available for diabetic peripheral neuropathy. Oxidative stress impairs endothelial cells, thereby leading to numerous pathological conditions. Increasing antioxidative ability is important to prevent cellular toxicity induced by reactive oxygen species. Epalrestat increases antioxidant defense factors such as glutathione and γ-glutamylcysteine ligase in vascular endothelial cells through activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). This increases suppression of oxidative stress-induced cellular toxicity. Cadmium is an industrial and environmental pollutant that targets the vascular endothelium. The vascular system is critically affected by cadmium toxicity. Therapeutic treatment against cadmium toxicity is chelation therapy that promotes metal excretion; however, cadmium chelators can cause renal toxicity. Therefore, safe and efficient therapeutic agents are required. Epalrestat suppresses cadmium-induced cytotoxicity in vascular endothelial cells through activation of Nrf2. In addition, epalrestat affects the intracellular levels of cadmium, cadmium transporter Zrt-Irt-like protein 8 (ZIP8), and metallothionein (MT). The upregulation of ZIP8 and MT may be involved in the suppression of cadmium-induced cytotoxicity by epalrestat. Drug repurposing is a new strategy for drug discovery in which the pharmacological action of existing medicines whose safety and pharmacokinetics have already been confirmed clinically and whose use has been approved is examined comprehensively at the molecular level. The results can be applied to the development of existing drugs for use as medicines for the treatment of other diseases. This review provides useful findings for future expansion of indications as research leading to drug repurposing of epalrestat.

Dihydromyricetin Attenuates Cerebral Ischemia Reperfusion Injury by Inhibiting SPHK1/mTOR Signaling and Targeting Ferroptosis.

Background: Dihydromyricetin (DHM) exerts protective effects in various brain diseases. The aim of this research was to investigate the biological role of DHM in cerebral ischemia reperfusion (I/R) injury. Methods: We generated a rat model of cerebral I/R injury by performing middle cerebral artery occlusion/reperfusion (MCAO/R). The neurological score and brain water content of the experimental rats was then evaluated. The infarct volume and extent of apoptosis in brain tissues was then assessed by 2,3,5-triphenyltetrazolium (TTC) and TdT-mediated dUTP nick end labeling (TUNEL) staining. Hippocampal neuronal cells (HT22) were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) and cell counting kit-8 (CCK-8) assays and flow cytometry were performed to detect cell viability and apoptosis. The levels of lipid reactive oxygen species (ROS) and iron were detected and the expression levels of key proteins were assessed by Western blotting. Results: DHM obviously reduced neurological deficits, brain water content, infarct volume and cell apoptosis in the brain tissues of MCAO/R rats. DHM repressed ferroptosis and inhibited the sphingosine kinase 1 (SPHK1)/mammalian target of rapamycin (mTOR) pathway in MCAO/R rats. In addition, DHM promoted cell viability and repressed apoptosis in OGD/R-treated HT22 cells. DHM also suppressed the levels of lipid ROS and intracellular iron in OGD/R-treated HT22 cells. The expression levels of glutathione peroxidase 4 (GPX4) was enhanced while the levels of acyl-CoA synthetase long-chain family member 4 (ACSL4) and phosphatidylethanolamine binding protein 1 (PEBP1) were reduced in OGD/R-treated HT22 cells in the presence of DHM. Moreover, the influence conferred by DHM was abrogated by the overexpression of SPHK1 or treatment with MHY1485 (an activator of mTOR). Conclusion: This research demonstrated that DHM repressed ferroptosis by inhibiting the SPHK1/mTOR signaling pathway, thereby alleviating cerebral I/R injury. Our findings suggest that DHM may be a candidate drug for cerebral I/R injury treatment.

Chemopreventive effects of FITOPROT against 5-fluorouracil-induced toxicity in HaCaT cells.

AIMS: This study evaluated the mechanisms involved in the chemopreventive effects of a mucoadhesive formulation (FITOPROT), containing curcuminoids from Curcuma longa L. (Zingiberaceae) and Bidens pilosa L. (Asteraceae) extract, against 5-FU-induced cellular toxicity using an in vitro oral mucositis model. MAIN METHODS: Effects of FITOPROT on 5-FU-induced cytotoxicity in HaCaT and SSC-4 cells were evaluated by MTT assay. For mechanistic analyses, HaCaT cells were first pretreated with FITOPROT (0.005%) for 24h followed by treatment with FITOPROT and simultaneously exposed to 5-FU (10µg/mL) for additional 24h. KEY FINDINGS: FITOPROT was able to protect HaCaT cells from 5-FU-triggered cell damage. Moreover, the FITOPROT+5-FU association showed higher cytotoxic effects on SSC-4 cancer cells. Flow cytometry and/or fluorescence microscopy analysis showed FITOPROT was able to significantly reduce ROS generation and prevent mitochondrial changes in HaCaT cells. In addition, it avoided the release of cytochrome c from mitochondria to the cytoplasm in cells exposed to 5-FU, and restored their proliferative activity via Ki-67 expression. Furthermore, FITOPROT regulated 5-FU-induced oxidative stress via Nrf2 involvement. HaCaT cells pretreated/treated with FITOPROT also showed normal expression of TNF-R1 and NF-κB inflammatory proteins and decreased levels of pro-inflammatory cytokines (TNF, IL-1ß, IL-6 and IL-8). Moreover, a high-resolution liquid chromatography-mass spectrometry analysis showed the presence of flavonoids rutin, glucoronylated quercetin and dimethylquercetin rutenoside in FITOPROT. SIGNIFICANCE: It was showed that FITOPROT, an antioxidant phytochemicals-rich mucoadhesive formulation, exerts chemopreventive effects against 5-FU-triggered toxicity through antioxidant and anti-inflammatory mechanisms and restoration of proliferative capacity in HaCaT cells.