Epiberberine induced p53/p21-dependent G2/M cell cycle arrest and cell apoptosis in gastric cancer cells by activating γ-aminobutyric acid receptor- ß3.

BACKGROUND AND PURPOSE: Epiberberine (EPI) is one of the most important bioalkaloid found in the rhizome of Coptis chinensis, which has been observed to exhibit pharmaceutical effects against gastric cancer (GC). Nevertheless, the potential mechanism of EPI against GC cells still remains unclear. This study aimed to identify the core receptor on GC cells through which EPI inhibited the growth of GC cells and to explore the underlying inhibitory mechanisms. METHODS: To identify hub receptor targets that respond to EPI treatment, RNA sequencing (RNA-Seq) data from a tumor-bearing mouse model were analyzed using bioinformatics method and molecular docking. The binding interaction between EPI and GABRB3 was validated through western blotting based-cellular thermal shift assay (WB-CETSA). To further verify the binding region between EPI and GABRB3 through circular dichroism (CD) chromatography, fragments of the extracellular and transmembrane domains of the GABRB3 protein were expressed and purified in vitro. Stable cell lines with the overexpression or knockdown of GABRB3 were established using the recombinant lentivirus system. MTT ((3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide)) assay, colony formation assay, invasion and migration experiments, and flow cytometry were conducted to validate the inhibitory effect of EPI on the GC cells via GABRB3. Additionally, western blotting was utilized to explore the potential inhibitory mechanisms. RESULTS: Through the combination of multiple bioinformatics methods and molecular docking, we found that the γ-aminobutyric acid type A receptor subunit -ß3 (GABRB3) might be the critical receptor target in response to EPI treatment. The results of WB-CETSA analysis indicated that EPI significantly promoted the thermostability of the GABRB3 protein. Importantly, EPI could directly bind to GABRB3 and alter the secondary structure of GABRB3 fragments similar to the natural agonist, γ-aminobutyric acid (GABA). The EPI-induced suppression of the malignant phenotype of GC cells was dependent on the presence of GABRB3. GABRB3 expression was positively correlated with TP53 in patients with GC. The binding of EPI to GABRB3 stimulated p53 accumulation in GC cells. This activated the p21/CDK1/cyclinB1 pathway, resulting in G2/M cell cycle arrest, and induced the Bcl-2/BAX/Caspase axis-dependent cell apoptosis. CONCLUSION: This study revealed the target receptor for EPI in GC cells and provided new insights into its anticancer mechanisms.

Integrating transcriptomics and network pharmacology to reveal the mechanisms of total Rhizoma Coptidis alkaloids against nonalcoholic steatohepatitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Non-alcoholic steatohepatitis (NASH) has emerged as a major cause of cirrhosis and hepatocellular carcinoma, posing a significant threat to public health. Rhizoma Coptidis, a traditional Chinese medicinal herb has been shown to have significant curative effects on liver diseases. Total Rhizoma Coptidis Alkaloids (TRCA) is a primarily alkaloid mixture extracted from Rhizoma Coptidis, and its constituents are widely accepted to have hepatoprotective effects. AIM OF THE STUDY: This work aimed to investigate the efficacy and potential mechanisms of TRCA in ameliorating NASH through both in vitro experiments and in vivo mouse models. MATERIALS AND METHODS: The study employed a mice model induced by a high-fat diet (HFD) to evaluate the effectiveness and pharmacological mechanisms of TRCA in alleviating NASH. Transcriptomic sequencing and network pharmacology were used to explore the possible targets and mechanisms of TRCA to ameliorate NASH. Further validation was performed in free fatty acid (FFA)-induced human hepatocytes (LO2) and human hepatocellular carcinoma cells (HepG2). RESULTS: TRCA effectively ameliorated the main features of NASH such as lipid accumulation, hepatitis and hepatic fibrosis in the liver tissue of mice induced by HFD, as well as improved glucose tolerance and insulin resistance in mice. Combined with transcriptomic and network pharmacological analyses, 68 core targets associated with the improvement of NASH by TRCA were obtained. According to the KEGG results, the core targets were significantly enriched in the PI3K-AKT signaling pathway whereas TRCA ameliorated the aberrant down-regulation of the PI3K-AKT signaling pathway induced by HFD. Furthermore, the five highest-ranked genes were obtained by PPI network analysis. Moreover, our findings suggest that TRCA may impede the progression of HFD-induced NASH by regulating the expression of PPARG, MMP9, ALB, CCL2, and EGFR. CONCLUSIONS: TRCA can ameliorate HFD-induced liver injury by modulating aberrant downregulation of the PI3K-AKT signaling pathway. Key proteins such as PPARG, MMP9, ALB, CCL2, and EGFR may be critical targets for TRCA to ameliorate NASH. This finding supports using Rhizoma Coptidis, a well-known herbal medicine, as a potential therapeutic agent for NASH.

Coptisine inhibits Helicobacter pylori and reduces the expression of CagA to alleviate host inflammation in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Helicobacter pylori (H. pylori) is a major pathogen colonized in the human stomach and is implicated in gastritis, peptic ulcer, and gastric carcinoma. Antibiotics are useful for eradicating H. pylori but failed for drug resistance, making it urgent to develop effective and safe drugs. Rhizoma Coptidis was reported as one of the most effective Chinese medicines to treat H. pylori-related gastrointestinal diseases, while the precise antimicrobial mechanism remains unclear. Thus, it is of great significance to study the antimicrobial ingredients and corresponding mechanisms of Rhizoma Coptidis. AIM OF THE STUDY: To search for the most effective alkaloid against H. pylori in Rhizoma Coptidis and illustrate the probable mechanisms. MATERIALS AND METHODS: Five main alkaloids in Rhizoma Coptidis were isolated. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested to determine the most effective one. Bacterial growth experiments, Annexin V-FITC/PI staining, TUNEL staining, and transmission electron microscopy (TEM) were performed to further study the anti-H. pylori activity of coptisine (Cop). The in vivo effect of Cop on H. pylori eradication rate and H. pylori-induced inflammation was investigated in mice. Transcriptomics was used to understand the underlying mechanism of eradicating H. pylori and reducing host inflammation. Western blot, RT-PCR, and ELISA experiments were utilized and confirmed that cagA was one of the targets of Cop. RESULTS: According to the MIC and MBC, Cop was the most effective alkaloid against H. pylori, especially with no drug resistance developed. In vitro experiments showed that Cop inhibited H. pylori by inducing DNA fragmentation, phosphatidylserine exposure, and membrane damage. Cop (150 mg/kg/day) effectively eradicated H. pylori in mice and reduced the levels of IL-2 and IL-6 to relieve gastric inflammation. Transcriptomic analysis revealed that virulence factor cagA was one of the hub genes associated with the inflammation-improving effect of Cop. That is, Cop could decrease the expression of CagA and subsequently reduce the translocation of CagA to gastric epithelial cells, thereby improving the morphology of hummingbird-like phenotype induced by CagA and alleviating inflammation. CONCLUSIONS: Cop is the most effective alkaloid in Rhizoma Coptidis and might act through multiple mechanisms for H. pylori eradication along with reducing the expression of CagA to alleviate inflammation.