Sclareol attenuates liver fibrosis through SENP1-mediated VEGFR2 SUMOylation and inhibition of downstream STAT3 signaling.

Liver fibrosis is a key global health care burden. Sclareol, isolated from Salvia sclarea, possesses various biological activities. Its effect on liver fibrosis remains unknown. This study was proposed to evaluate the antifibrotic activity of sclareol (SCL) and explore its underlying mechanisms. Stimulated hepatic stellate cells served as an in vitro liver fibrosis model. The expression of fibrotic markers was assessed by western blot and real-time PCR. Two classical animal models, bile duct-ligated rats and carbon tetrachloride-treated mice, were utilized for the in vivo experiments. The liver function and fibrosis degree were determined by serum biochemical and histopathological analyses. VEGFR2 SUMOylation was analyzed using coimmunoprecipitation assay. Our results indicated that SCL treatment restricted the profibrotic propensity of activated HSCs. In fibrotic rodents, SCL administration alleviated hepatic injury and reduced collagen accumulation. Mechanistic studies indicated that SCL downregulated the protein level of SENP1 and enhanced VEGFR2 SUMOylation in LX-2 cells, which affected its intracellular trafficking. Blockade of the interaction between VEGFR2 and STAT3 was observed, resulting in the suppression of downstream STAT3 phosphorylation. Our findings demonstrated that SCL has therapeutic efficacy against liver fibrosis through mediating VEGFR2 SUMOylation, suggesting that SCL may be a potential candidate compound for its treatment.

Dehydromevalonolactone ameliorates liver fibrosis and inflammation by repressing activation of NLRP3 inflammasome.

Liver fibrosis is an important process in chronic liver disease and is strongly related to poor prognosis. Dehydromevalonolactone (C8) is a natural product isolated from a fungus of Fusarium sp. CPCC 401218, and its pharmacological activity has never been reported before. In this study, the potential of C8 as an anti-hepatic fibrosis agent was investigated. In human hepatic stellate cell (HSC) line LX-2, C8 suppressed the increased expression of COL1A1 and α-SMA induced by TGFß1, which indicated that C8 could repress the activation of HSCs. In bile duct ligated rats, C8 administration (100 mg/kg, i.p.) markedly attenuated liver injury, fibrosis, and inflammation, and suppressed the expression of the macrophage surface marker F4/80. In terms of mechanism, C8 treatment blocked the activation of the NLRP3 inflammasome, which was stimulated by LPS and nigericin in bone marrow-derived macrophages (BMDMs) and companied by the release of active IL-1ß. In addition, the activation of LX-2 cells induced by IL-1ß released from BMDMs was also inhibited after C8 administration, which indicated that C8 repressed HSCs activation by inhibiting the activation of NLRP3 inflammasome in macrophages. Furthermore, C8 exhibited the effects of anti-fibrosis and inhibiting the expression of NLRP3 inflammasome in non-alcoholic steatohepatitis (NASH) mice. Finally, C8 can be commendably absorbed in vivo and was safe for mice at the concentration of 1000 mg/kg (p.o.). In summary, our study reveals that C8 ameliorates HSCs activation and liver fibrosis in cholestasis rats and NASH mice by inhibiting NLRP3 inflammasome in macrophages, and C8 might be a safe and effective candidate for the treatment of liver fibrosis.

Discovery of 1,8-naphthalidine derivatives as potent anti-hepatic fibrosis agents via repressing PI3K/AKT/Smad and JAK2/STAT3 pathways.

Liver fibrosis is one of the most common pathological consequences of chronic liver diseases (CLD). To develop effective antifibrotic strategies, a novel class of 1-(substituted phenyl)-1,8-naphthalidine-3-carboxamide derivatives were designed and synthesized. By means of the collagen type I α 1 (COL1A1)-based screening and cytotoxicity assay in human hepatic stellate cell (HSC) line LX-2, seven compounds were screened out from total 60 derivatives with high inhibitory effect and relatively low cytotoxicity for further COL1A1 mRNA expression analysis. It was found that compound 17f and 19g dose-dependently inhibited the expression of fibrogenic markers, including α-smooth muscle actin (α-SMA), matrix metalloprotein 2 (MMP-2), connective tissue growth factor (CTGF) and transforming growth factor ß1 (TGFß1) on both mRNA and protein levels. Further mechanism studies indicated that they might suppress the hepatic fibrogenesis via inhibiting both PI3K/AKT/Smad and non-Smad JAK2/STAT3 signaling pathways. Furthermore, 19g administration attenuated hepatic histopathological injury and collagen accumulation, and reduced fibrogenesis-associated protein expression in liver tissues of bile duct ligation (BDL) rats, showing significant antifibrotic effect in vivo. These findings identified 1,8-naphthalidine derivatives as potent anti-hepatic fibrosis agents, and provided valuable information for further structure optimization.

Pantoprazole ameliorates liver fibrosis and suppresses hepatic stellate cell activation in bile duct ligation rats by promoting YAP degradation.

Liver fibrosis is one of the most severe pathologic consequences of chronic liver diseases, and effective therapeutic strategies are urgently needed. Proton pump inhibitors (PPIs) are H+/K+-ATPase inhibitors and currently used to treat acid-related diseases such as gastric ulcers, which have shown other therapeutic effects in addition to inhibiting acid secretion. However, few studies have focused on PPIs from the perspective of inhibiting hepatic fibrosis. In the present study, we investigated the effects of pantoprazole (PPZ), a PPI, against liver fibrosis in a bile duct ligation (BDL) rat model, human hepatic stellate cell (HSC) line LX-2 and mouse primary HSCs (pHSCs), and explored the potential mechanisms underlying the effects of PPZ in vitro and in vivo. In BDL rats, administration of PPZ (150 mg· kg-1· d-1, i.p. for 14 d) significantly attenuated liver histopathological injury, collagen accumulation, and inflammatory responses, and suppressed fibrogenesis-associated gene expression including Col1a1, Acta2, Tgfß1, and Mmp-2. In LX-2 cells and mouse pHSCs, PPZ (100-300 µM) dose-dependently suppressed the levels of fibrogenic markers. We conducted transcriptome analysis and subsequent validation in PPZ-treated LX-2 cells, and revealed that PPZ inhibited the expression of Yes-associated protein (YAP) and its downstream targets such as CTGF, ID1, survivin, CYR61, and GLI2. Using YAP overexpression and silencing, we demonstrated that PPZ downregulated hepatic fibrogenic gene expression via YAP. Furthermore, we showed that PPZ promoted the proteasome-dependent degradation and ubiquitination of YAP, thus inhibiting HSC activation. Additionally, we showed that PPZ destabilized YAP by disrupting the interaction between a deubiquitinating enzyme OTUB2 and YAP, and subsequently blocked the progression of hepatic fibrosis.

Advances in understanding the regulatory mechanism of organic solute transporter α-ß.

The organic solute transporter α-ß (OSTα-OSTß) is a heteromeric transporter localized to the basolateral membranes of liver, intestinal, and kidney epithelial cells and functions to extrude bile acids and steroids from these tissues. OSTα-OSTß expression is variable among species and tissues. This transporter plays important roles in maintaining BA homeostasis and may correlate with the progression of diseases relevant to cholestasis or BA malabsorption. Crosstalk between multiple nuclear receptors and cytokines reveals a more intricate means of regulating OSTα-OSTß. Human OSTα/ß and mouse Ostα/ß promoters are endowed with binding sites for several transcription factors. This review aims to uncover the current regulatory mechanism of OSTα-OSTß, explain the rationale underlying this approach and provide practical evidence. Therapeutic strategies targeting OSTα-OSTß or its upstream regulators may be essential to correct abnormal BA levels and intervene in the progression of diseases relevant to the disturbance of BA homeostasis.

Costunolide represses hepatic fibrosis through WW domain-containing protein 2-mediated Notch3 degradation.

BACKGROUND AND PURPOSE: This study investigates the antifibrotic activities and potential mechanisms of costunolide (COS), a natural sesquiterpene compound. EXPERIMENTAL APPROACH: Rats subjected to bile duct ligation and mice challenged with CCl4 were used to study the antifibrotic effects of COS in vivo. Mouse primary hepatic stellate cells (pHSCs) and human HSC line LX-2 also served as an in vitro liver fibrosis models. The expression of fibrogenic genes and signaling proteins in the neurogenic locus notch homologue protein 3 (Notch3)-hairy/enhancer of split-1 (HES1) pathway was examined using western blot and/or real-time PCR. Notch3 degradation was analysed using immunofluorescence and coimmunoprecipitation. KEY RESULTS: In animals, COS administration attenuated hepatic histopathological injury and collagen accumulation and reduced the expression of fibrogenic genes. COS time- and dose-dependently suppressed the levels of fibrotic markers in LX-2 cells and mouse pHSCs. Mechanistic studies showed COS destabilized Notch3 and subsequently inhibited the Notch3-HES1 pathway, thus inhibiting HSC activation. Furthermore, COS blocked the WW domain-containing protein 2 (WWP2)/protein phosphatase 1G (PPM1G) interaction and enhanced the effect of WWP2 on Notch3 degradation. CONCLUSIONS AND IMPLICATIONS: COS exerted potent antifibrotic effects in vitro and in vivo by disrupting the WWP2/PPM1G complex, promoting Notch3 degradation and inhibiting the Notch3/HES1 pathway. This indicates that COS may be a potential therapeutic candidate for the treatment of liver fibrosis.

Pantoprazole pretreatment elevates sensitivity to vincristine in drug-resistant oral epidermoid carcinoma in vitro and in vivo.

Resistance to chemotherapeutic agents is a major cause of treatment failure in patients with oral cancer. Proton pump inhibitors (PPIs), essentially H+-K+-ATPase inhibitors which are currently used in the treatment of acid related diseases, have demonstrated promising antitumor and chemo-sensitizing efficacy. The main purpose of the present study was to investigate whether pantoprazole (PPZ, one of PPIs) could increase the sensitivity of chemoresistant oral epidermoid carcinoma cells (KB/V) to vincristine (VCR) and elucidate the underlying action mechanism. Results showed that combination treatment of PPZ and VCR synergistically inhibited the proliferation of KB/V cells in vitro and in vivo. Furthermore, administration of PPZ and VCR not only induce apoptosis and G2/M phase arrest in KB/V cells but also suppress the migration and invasion of KB/V cells. The mechanism underlying synergistic anti-tumor effect of PPZ and VCR was related to the inhibition of the function and expression of P-glycoprotein (P-gp) and the down-regulation of EGFR/MAPK and PI3K/Akt/mTOR signaling pathways in KB/V cells. Additionally, we observed that PPZ treatment induced an increase in lysosomal pH and inhibited the activity of lysosomal enzyme acid phosphatase in KB/V cells, which could functionally reduce the sequestration of VCR in lysosomes and sensitized KB/V cells to VCR. In conclusion, our study demonstrated that PPZ could be included in new combined therapy of human oral cancer (especially on VCR-resistant therapy) together with VCR.

Regulation and role of nuclear factor-E2-related factor 2 (Nrf2) in multidrug resistance of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) chemoresistance, which is regarded as a kind of stress management reaction to chemotherapy drugs, severely hinders the therapy outcomes of HCC treatment. Stress management is generally achieved by activating certain signal pathways and chemical factors, among which, nuclear factor-E2-related factor2 (Nrf2) is a key factor in HCC chemoresistance formation. Nrf2 is a nuclear factor that coordinates the induction and expression of a battery of genes encoding cytoprotective proteins when participating in the Nrf2antioxidant response element (Nrf2/ARE) pathway, which is one of the most important intracellular antioxidant stress pathways. This review summarizes the recent understanding of the involvement of Nrf2 in the chemoresistance of liver cancer, its target proteins, expression regulation and potential Nrf2 inhibitors that sensitize chemotherapy drugs in HCC.

Repositioning of proton pump inhibitors in cancer therapy.

Drug repositioning, as a smart way to exploit new molecular targets of a known drug, has been gaining increasing attention in the discovery of anti-cancer drugs. Proton pump inhibitors (PPIs) as benzimidazole derivatives, which are essentially H+-K+-ATPases inhibitors, are commonly used in the treatment of acid-related diseases such as gastric ulcer. In recent years, exploring the new application of PPIs in anti-cancer field has become a hot research topic. Interestingly, cancer cells display an alkaline intracellular pH and an acidic extracellular pH. The extracellular acidity of tumors can be corrected by PPIs that are selectively activated in an acid milieu. It is generally believed that PPIs might provoke disruption of pH homeostasis by targeting V-ATPase on cancer cells, which is the theoretical basis for PPIs to play an anti-cancer role. Numerous studies have shown specialized effects of the PPIs on tumor cell growth, metastasis, chemoresistance, and autophagy. PPIs may really represent new anti-cancer drugs due to better safety and tolerance, the potential selectivity in targeting tumor acidity, and the ability to inhibit mechanism pivotal for cancer homeostasis. In this review, we focus on the new therapeutic applications of PPIs in multiple cancers, explaining the rationale behind this approach and providing practical evidence.

DHPAC, a novel synthetic microtubule destabilizing agent, possess high anti-tumor activity in vincristine-resistant oral epidermoid carcinoma in vitro and in vivo.

Multidrug resistance (MDR) is one of major obstacles to effective chemotherapeutic treatment of cancer. This study showed that DHPAC, 2-(6-ethoxy-3-(3-ethoxyphenylamino) -1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy) acetamide, a novel compound that binds to the same site on microtubules as colchicine, has high anti-tumour activity in vincristine-resistant oral epidermoid carcinoma (KB/V) cells. It found that the presence of DHPAC strongly inhibited KB/V cell growth in vivo and in mice xenograft. The inhibitory effect of DHPAC is much stronger than that by colchicine in these KB/V cells (IC50: 64.4nM and 458.0nM respectively). Treatment of the cells with DHPAC induced cell apoptosis by reducing mitochondrial membrane potential and altered the expression of several apoptosis-related proteins such as Bcl-2, Bax, Caspase-9, Cytochrome c and PARP. DHPAC treatment also caused cell rest in G2/M phase by regulating of the expression of a number of cell cycle-related proteins (e.g. Cyclin B1, Cdc2, Cdc25b, Cdc25c, RSK2). Furthermore, DHPAC presence inhibits PTEN phosphorylation and PTEN/Akt/NF-κB signalling. Thus, DHPAC has potent anti-cancer activity in MDR tumuors and may be a potential therapeutic agent for the treatment of vincristine-resistant human oral epidermoid carcinoma.