The flavonoid GL-V9 alleviates liver fibrosis by triggering senescence by regulating the transcription factor GATA4 in activated hepatic stellate cells

Inhibition of Rho GEFs attenuates pulmonary fibrosis through suppressing myofibroblast activation and reprogramming profibrotic macrophages

Idiopathic pulmonary fibrosis has a poor prognosis, with existing medications only partially alleviating symptoms, highlighting the urgent need for new therapeutic approaches. The dysregulations of Rho GTPases/ROCK are related with various diseases, including fibrosis. Nevertheless, the development of drugs for pulmonary fibrosis treatment has predominantly concentrated on ROCK inhibitors. Small GTPases have been historically recognized as "undruggable". Here, we explore a novel Rho GEFs inhibitor GL-V9, and find that GL-V9 alleviates bleomycin-induced pulmonary fibrosis in mice by inhibiting myofibroblast activation and reprogramming profibrotic macrophages. Distinct from the mechanisms of the first-line drug Nintedanib, GL-V9 binds to the DH/PH domain of Rho GEFs and block the activation of Rho GTPase signaling. This action subsequently suppresses myofibroblast activation by interfering with Rho GTPase-dependent cytoskeletal reorganization and the activity of MRTF and YAP, and inhibits M2 macrophage polarization by modulating RhoA/STAT3 activity. The discovery of new regulatory mechanisms of GL-V9 suggests that targeting Rho GEFs represents a potent strategy for pulmonary fibrosis treatment.

Flavonoid GL-V9 suppresses development of human hepatocellular cancer cells by inhibiting Wnt/β-Cantenin signaling pathway

Distant metastasis and post-operative recurrence of tumours are the main causes of death in patients with hepatocellular carcinoma (HCC). In recent years, flavonoids have been found to achieve effective anticancer effects by inhibiting cancer cell proliferation and inducing apoptosis, inhibiting cancer cell invasion and metastasis and neovascularization. GL-V9 is a newly synthesized flavonoid that has been demonstrated anticancer effects in a variety of tumors, but its anticancer effects in HCC and its related mechanisms are still unclear. In this study, we investigated the anti-proliferative, anti-invasive and anti-migratory activities of GL-V9 in HCC cells by MTT method cell proliferation assay, plate cloning assay, transwell invasion assay and cell scratching assay. Based on the results, we found that GL-V9 inhibits the EMT process through a pathway that inhibits Wnt/β-Cantenin pathway signaling, thereby reducing the proliferation, migration and invasion ability of HCC cells. Therefore, GL-V9 may be a novel potential therapeutic agent to inhibit HCC cell metastasis.

Sorafenib-mediated cleavage of p62 initiates cellular senescence as a mechanism to evade its anti-hepatocellular carcinoma efficacy

Hepatocellular carcinoma (HCC) stands as one of the most aggressively advancing and lethal malignancies. Sorafenib is presently endorsed as a primary therapy for advanced liver cancer, but its resistance presents a formidable challenge. Previous studies have implicated a connection between post-sorafenib discontinuation rebound and the development of drug resistance, yet the underlying mechanism remains elusive. In this study, we discerned that Sorafenib induced a senescent phenotype in HCC cells and caused a cleavage of ubiquitin-binding protein p62. Mechanistic studies establish that truncated p62 drives cellular senescence by promoting proteasome-dependent degradation of 4EBP1. Furthermore, truncated p62 induced specific ubiquitination of 4EBP1. Crucially, virtual drug screening uncovered that dacinostat inhibited cellular senescence by blocking sorafenib-induced p62 cleavage. In summary, our findings imply that truncated p62 from sorafenib cleavage promotes senescence via 4EBP1 degradation. The prevention of p62 cleavage could emerge as a crucial strategy for impeding the sorafenib-induced cellular senescence.

GL-V9 inhibits the activation of AR-AKT-HK2 signaling networks and induces prostate cancer cell apoptosis through mitochondria-mediated mechanism

Prostate cancer (PCa) is a serious health concern for men due to its high incidence and mortality rate. The first therapy typically adopted is androgen deprivation therapy (ADT). However, patient response to ADT varies, and 20-30% of PCa cases develop into castration-resistant prostate cancer (CRPC). This article investigates the anti-PCa effect of a drug candidate named GL-V9 and highlights the significant mechanism involving the AKT-hexokinase II (HKII) pathway. In both androgen receptor (AR)-expressing 22RV1 cells and AR-negative PC3 cells, GL-V9 suppressed phosphorylated AKT and mitochondrial location of HKII. This led to glycolytic inhibition and mitochondrial pathway-mediated apoptosis. Additionally, GL-V9 inhibited AR activity in 22RV1 cells and disrupted the feedback activation of AKT signaling in condition of AR inhibition. This disruption greatly increased the anti-PCa efficacy of the AR antagonist bicalutamide. In conclusion, we present a novel anti-PCa candidate and combination drug strategies to combat CRPC by intervening in the AR-AKT-HKII signaling network.

Emodin promotes hepatic stellate cell senescence and alleviates liver fibrosis via a nuclear receptor (Nur77)-mediated epigenetic regulation of glutaminase 1

BACKGROUND AND PURPOSE

Senescence in hepatic stellate cells (HSCs) limits liver fibrosis. Glutaminolysis promotes HSC activation. Here, we investigated how emodin affected HSC senescence involving glutaminolysis.

EXPERIMENTAL APPROACH

Senescence, glutaminolysis metabolites, Nur77 nuclear translocation, glutaminase 1 (GLS1) promoter methylation and related signalling pathways were examined in human HSC-LX2 cells using multiple cellular and molecular approaches. Fibrotic mice with shRNA-mediated knockdown of Nur77 were treated with emodin-vitamin A liposome for investigating the mechanisms in vivo. Human fibrotic liver samples were examined to verify the clinical relevance.

KEY RESULTS

Emodin upregulated several key markers of senescence and inhibited glutaminolysis cascade in HSCs. Emodin promoted Nur77 nuclear translocation, and knockdown of Nur77 abolished emodin blockade of glutaminolysis and induction of HSC senescence. Mechanistically, emodin facilitated Nur77/DNMT3b interaction and increased GLS1 promoter methylation, leading to inhibited GLS1 expression and blockade of glutaminolysis. Moreover, the glutaminolysis intermediate α-ketoglutarate promoted extracellular signal-regulated kinase (ERK) phosphorylation, which in turn phosphorylated Nur77 and reduced its interaction with DNMT3b. This led to decreased GLS1 promoter methylation and increased GLS1 expression, forming an ERK/Nur77/glutaminolysis positive feedback loop. However, emodin repressed ERK phosphorylation and interrupted the feedback cascade, stimulating senescence in HSCs. Studies in mice showed that emodin-vitamin A liposome inhibited glutaminolysis and induced senescence in HSCs, and consequently alleviated liver fibrosis; but knockdown of Nur77 abrogated these beneficial effects. Similar alterations were validated in human fibrotic liver tissues.

CONCLUSIONS AND IMPLICATIONS

Emodin stimulated HSC senescence through interruption of glutaminolysis. HSC-targeted delivery of emodin represented a therapeutic option for liver fibrosis.

Aqueous extract of Amydrium sinense (Engl.) H. Li alleviates hepatic fibrosis by suppressing hepatic stellate cell activation through inhibiting Stat3 signaling

Background: The present study aimed to investigate the protective effect of the water extract of Amydrium sinense (Engl.) H. Li (ASWE) against hepatic fibrosis (HF) and clarify the underlying mechanism. Methods: The chemical components of ASWE were analysed by a Q-Orbitrap high-resolution mass spectrometer. In our study, an in vivo hepatic fibrosis mouse model was established via an intraperitoneal injection of olive oil containing 20% CCl₄. In vitro experiments were conducted using a hepatic stellate cell line (HSC-T6) and RAW 264.7 cell line. A CCK-8 assay was performed to assess the cell viability of HSC-T6 and RAW264.7 cells treated with ASWE. Immunofluorescence staining was used to examine the intracellular localization of signal transducer and activator of transcription 3 (Stat3). Stat3 was overexpressed to analyse the role of Stat3 in the effect of ASWE on HF. Results: Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that candidate targets of ASWE, associated with protective effects against hepatic fibrosis, were related to inflammation response. ASWE ameliorated CCl₄-induced liver pathological damage and reduced the liver index and alanine transaminase (ALT) and aspartate transaminase (AST) levels. ASWE also decreased the serum levels of collagen Ⅰ (Col Ⅰ) and hydroxyproline (Hyp) in CCl₄-treated mice. In addition, the expression of fibrosis markers, including α-SMA protein and Acta2, Col1a1, and Col3a1 mRNA, was downregulated by ASWE treatment in vivo. The expression of these fibrosis markers was also decreased by treatment with ASWE in HSC-T6 cells. Moreover, ASWE decreased the expression of inflammatory markers, including the Tnf-α, Il6 and Il1β, in RAW264.7 cells. ASWE decreased the phosphorylation of Stat3 and total Stat3 expression and reduced the mRNA expression of the Stat3 gene in vivo and in vitro. ASWE also inhibited the nuclear shuttling of Stat3. Overexpression of Stat3 weakened the therapeutic effect of ASWE and accelerated the progression of HF. Conclusion: The results show that ASWE protects against CCl₄-induced liver injury by suppressing fibrosis, inflammation, HSC activation and the Stat3 signaling pathway, which might lead to a new approach for preventing HF.