Human gastric cancer progression and stabilization of ATG2B through RNF5 binding facilitated by autophagy-associated CircDHX8.

The role of circDHX8 in the interplay between autophagy and gastric cancer (GC) progression remains unclear. In this study, we investigated the mechanism underlying the role of hsa_circ_003899 (circDHX8) in the malignancy of GC. Differential expression of circRNAs between GC and normal tissues was determined using circle-seq and microarray datasets (GSE83521). These circRNAs were validated using qPCR and Sanger sequencing. The function of circDHX8 was investigated through interference with circDHX8 expression experiments using in vitro and in vivo functional assays. Western blotting, immunofluorescence, and transmission electron microscopy were used to establish whether circDHX8 promoted autophagy in GC cells. To elucidate the mechanism underlying the circDHX8-mediated regulation of autophagy, we performed bioinformatics analysis, RNA pull-down, mass spectrometry (MS), RNA immunoprecipitation (RIP), and other western Blot related experiments. Hsa_circ_0003899 (circDHX8) was identified as upregulated and shown to enhance the malignant progression in GC cells by promoting cellular autophagy. Mechanistically, circDHX8 increased ATG2B protein levels by preventing ubiquitin-mediated degradation, thereby facilitating cell proliferation and invasion in GC. Additionally, circDHX8 directly interacts with the E3 ubiquitin-protein ligase RNF5, inhibiting the RNF5-mediated degradation of ATG2B. Concurrently, ATG2B, an acetylated protein, is subjected to SIRT1-mediated deacetylation, enhancing its binding to RNF5. Consequently, we established a novel mechanism for the role of circDHX8 in the malignant progression of GC.

Depression promotes lung carcinoma progression by regulating the tumor microenvironment in tumor-bearing models of C57BL/6J mice.

Psychological stress is a common etiology among patients with lung cancer and serves as a potential indication of poor prognosis and advanced cancer clinical stage. Evidence indicates that depression is positively correlated with the evolvement of lung carcinoma. Nevertheless, the mechanisms underlying the effects of mental disorder on lung cancer have not been considerably and systemically explored. We hypothesized that mental disorder may affect the adjustment of the tumor microenvironment and immune cells. We used the chronic unpredictable mild stress (CUMS) procedure to induce depressed mice models and established tumor-bearing models of C57BL/6 J mice. Results revealed that the worsening of lung cancer was notably hastened in the CUMS + tumor group. Notably, the expression of PD-L1 in tumor issues increased in the tumor microenvironment, accompanied with a decline in the levels of CD8. On the basis of the date of tumor migration, our results indicated that MMPs and VEGF significantly increased after CUMS + tumor treatment. Thus, we demonstrated that modulation of the tumor microenvironment is pivotal for depression-promoted lung cancer migration.

Inhibitory effect of sinomenine on lung cancer cells via negative regulation of α7 nicotinic acetylcholine receptor.

Lung cancer is the leading cause of cancer deaths worldwide, with a high morbidity and less than 20% survival rate. Therefore, new treatment strategies and drugs are needed to reduce the mortality of patients with lung cancer. α7 nicotinic acetylcholine receptor (α7 nAChR), as a receptor of nicotine and its metabolites, is a potential target for lung cancer treatment. Our previous studies revealed that sinomenine plays anti-inflammation roles via α7 nAChR and down-regulates the expression of this receptor, thus increasing the inflammatory response. Hence, sinomenine is possibly a natural ligand of this receptor. In the present study, the effects of sinomenine on lung cancer A549 cells and tumor-bearing mice were determined to investigate whether this alkaloid has an inhibitory effect on lung cancer via α7 nAChR. CCK-8 assay, wound-healing test, and flow cytometry were performed for cell proliferation, cell migration, and apoptosis analysis in vitro, respectively. Xenograft mice were used to evaluate the effects of sinomenine in vivo. Results showed that sinomenine decreased cell proliferation and migration abilities but increased the percentage of apoptotic cells. Tumor volume in tumor-bearing mice was significantly reduced after sinomenine treatment compared with that in the vehicle group mice (p < 0.05). Furthermore, the effects of sinomenine were abolished by the α7 nAChR antagonist mecamylamine and the allosteric modulator PNU-120596, but no change occurred when the mice were pretreated with the muscarinic acetylcholine receptor antagonist atropine. Meanwhile, sinomenine suppressed α7 nAChR expression in vitro and in vivo, as well as the related signaling molecules pERK1/2 and ERK1/2 and the transcription factors TTF-1 and SP-1. By contrast, sinomenine up-regulated the expression of another transcription factor, Egr-1. These effects were restricted by mecamylamine and PNU but not by atropine. Results suggested that sinomenine can inhibit lung cancer via α7 nAChR in a negative feedback mode.

Early-Life Stress Induces Depression-Like Behavior and Synaptic-Plasticity Changes in a Maternal Separation Rat Model: Gender Difference and Metabolomics Study.

More than 300 million people suffer from depressive disorders globally. People under early-life stress (ELS) are reportedly vulnerable to depression in their adulthood, and synaptic plasticity can be the molecular mechanism underlying such depression. Herein, we simulated ELS by using a maternal separation (MS) model and evaluated the behavior of Sprague-Dawley (SD) rats in adulthood through behavioral examination, including sucrose preference, forced swimming, and open-field tests. The behavior tests showed that SD rats in the MS group were more susceptible to depression- and anxiety-like behaviors than did the non-MS (NMS) group. Nissl staining analysis indicated a significant reduction in the number of neurons at the prefrontal cortex and hippocampus, including the CA1, CA2, CA3, and DG regions of SD rats in the MS group. Immunohistochemistry results showed that the percentages of synaptophysin-positive area in the prefrontal cortex and hippocampus (including the CA1, CA2, CA3, and DG regions) slice of the MS group significantly decreased compared with those of the NMS group. Western blot analysis was used to assess synaptic-plasticity protein markers, including postsynaptic density 95, synaptophysin, and growth-associated binding protein 43 protein expression in the cortex and hippocampus. Results showed that the expression levels of these three proteins in the MS group were significantly lower than those in the NMS group. LC-MS/MS analysis revealed no significant differences in the peak areas of sex hormones and their metabolites, including estradiol, testosterone, androstenedione, estrone, estriol, and 5ß-dihydrotestosterone. Through the application of nontargeted metabolomics to the overall analysis of differential metabolites, pathway-enrichment results showed the importance of arginine and proline metabolism; pantothenate and CoA biosyntheses; glutathione metabolism; and the phenylalanine, tyrosine, and tryptophan biosynthesis pathways. In summary, the MS model caused adult SD rats to be susceptible to depression, which may regulate synaptic plasticity through arginine and proline metabolism; pantothenate and CoA biosyntheses; glutathione metabolism; and phenylalanine, tyrosine, and tryptophan biosyntheses.

SiNiSan ameliorates depression-like behavior in rats by enhancing synaptic plasticity via the CaSR-PKC-ERK signaling pathway.

BACKGROUND: Adverse stress in early life negatively influences psychiatric health by increasing the risk of developing depression and suicide in adulthood. Clinical antidepressants, such as fluoxetine, exhibit unsatisfactory results due to their low efficacy or intolerable side effects. SiNiSan (SNS), a traditional Chinese herbal formula, has been proven to have affirmatory antidepressive effects. However, the underlying mechanism remains poorly understood. Therefore, this study aimed to explore the impact and molecular mechanism of SNS treatment in rats exposed to neonatal maternal separation (MS)-combined young-adult chronic unpredictable mild stress (CUMS). METHOD: Seventy-two neonatal male Sprague-Dawley rats were randomly divided into six groups of 12 rats each: control + ddH2O, model + ddH2O, positive (fluoxetine: 5 mg/kg), SNS-low dose (2.5 g/kg), SNS-medium dose (5 g/kg), and SNS-high dose (10 g/kg). Behavioral tests included sucrose preference test, open-field test, and forced swimming test. Calcium sensitive receptor (CaSR), protein kinase C (PKC), ERK1/2, and synapse-associated proteins (PSD-95, GAP-43, and synaptophysin [Syn]) in the hippocampus (HIP) and prefrontal cortex (PFC) were assayed using Western blot. CaSR and Syn protein expression was measured by immunohistochemistry. RESULTS: MS-combined CUMS rats exhibited depression-like behavior. SNS exerted antidepressant effects on stress-induced depression-like behavior. The levels of CaSR, PKC, and p-ERK1/2 in the HIP and PFC decreased in stressed rats. SNS treatment significantly upregulated the expression of CaSR, PKC, and p-ERK1/2 in the HIP and PFC of adult stressed rats. CONCLUSION: MS-combined CUMS could develop depression-like behavior in adult. SNS exhibited antidepressive effects accompanied by improving synaptic plasticity by activation of the CaSR-PKC-ERK signaling pathway.