No abstract

Tumor occurrence and development are very complicated processes. In addition to the roles of exogenous carcinogenic factors, the body's internal factors also play important roles. These factors include the host response to the tumor and the tumor effect on the host. In particular, the proliferation, migration and activation of endothelial cells are involved in tumor angiogenesis. Angiogenesis is one of the hallmarks of cancer. In this study, we investigate whether plumbagin can abrogate angiogenesis-mediated tumor growth in hepatocellular carcinoma (HCC) and, if so, through which molecular mechanisms. We observed that in co-cultures of the human endothelial cell line EA.hy926 and the human hepatoma cell line SMMC-7721 and Hep3B, the hepatoma cells induced migration, invasion, tube formation and viability of the EA.hy926 cells in vitro, and these processes were inhibited by plumbagin. Real-Time PCR, Western Blot and Immunofluorescence staining showed that plumbagin treatment suppressed expression of angiogenesis pathways (PI3K-Akt, VEGF/KDR and Angiopoietins/Tie2) and angiogenic factors (VEGF, CTGF, ET-1, bFGF),which is associated with tumor angiogenesis in cancer cells and xenograft tumor tissues. Furthermore, plumbagin was also found to significantly reduce tumor growth in an orthotopic HCC mouse model and to inhibit tumor-induced angiogenesis in HCC patient xenografts. Taken together, our findings strongly suggest that plumbagin might be a promising anti-angiogenic drug with significant antitumor activity in HCC.

Background/Aims: Our previous studies have shown that plumbagin effectively inhibits hepatic stellate cell (HSC) proliferation. Thus, plumbagin-mediated anti-fibrotic effects in vivo merit further investigation. Methods: We used rat models to assess the potential benefits of plumbagin against CCl₄-induced liver fibrosis. Results: The results showed that plumbagin lowered the serum concentrations of liver functional enzymes (ALT, AST, ALB, TBIL) in CCl₄-fibrotic rats while reducing inflammatory cytokine levels (IL-6, TNF-a). As reflected in pathological examinations, rats that were administered plumbagin showed decreased collagen markers (HA, LN, PCIII and CIV) in liver tissues and improved hepatocellular impairments. In addition, plumbagin contributed to down-regulating NF-κB and TLR-4 mRNA in CCl₄-lesioned livers. As revealed in the immunohistochemical assay, plumbagin-administered rats showed reduced levels of a-SMA and TNF-a immunoreactive cells in liver tissue. Conclusion: Collectively, these findings offer appealing evidence that plumbagin may serve as an anti-fibrotic medication through inactivating the NF-κB/TLR-4 pathway that is associated with inflammatory reactions, thereby mitigating liver fibrosis.

No abstract

Critical roles for liver sinusoidal endothelial cells (LSECs) in liver fibrosis have been demonstrated, while little is known regarding the underlying molecular mechanisms of drugs delivered to the LSECs. Our previous study revealed that plumbagin plays an antifibrotic role in liver fibrosis. In this study, we investigated whether plumbagin alleviates capillarization of hepatic sinusoids by downregulating endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), laminin (LN), and type IV collagen on leptin-stimulated LSECs. We found that normal LSECs had mostly open fenestrae and no organized basement membrane. Leptin-stimulated LSECs showed the formation of a continuous basement membrane with few open fenestrae, which were the features of capillarization. Expression of ET-1, VEGF, LN, and type IV collagen was enhanced in leptin-stimulated LSECs. Plumbagin was used to treat leptin-stimulated LSECs. The sizes and numbers of open fenestrae were markedly decreased, and no basement membrane production was found after plumbagin administration. Plumbagin decreased the levels of ET-1, VEGF, LN, and type IV collagen in leptin-stimulated LSECs. Plumbagin promoted downregulation of ET-1, VEGF, LN, and type IV collagen mRNA. Altogether, our data reveal that plumbagin reverses capillarization of hepatic sinusoids by downregulation of ET-1, VEGF, LN, and type IV collagen.

No abstract

To explore the effect of curcumol on autophagy and ferroptosis of hepatic stellate cells, and to clarify the molecular mechanism of its anti-hepatic fibrosis. In the present study, we report that curcumol promotes the death of activated HSCs and reduces the deposition of extracellular matrix. Interestingly, curcumol treatment can trigger ferroptosis to eliminate activated HSCs characterized by iron overload, lipid ROS accumulation, glutathione depletion, and lipid peroxidation.Curcumol promotes HSC autophagy, which may be the key mechanism for its induction of ferroptosis. It is worth noting that the upregulation of nuclear receptor coactivator 4 (NCOA4) may play a key molecular mechanism. NCOA4 mediates the release of iron ions and induces the occurrence of ferroptosis. Overall, curcumol promotes autophagy in hepatic stellate cells, mediates the degradation of NCOA4 and FTH1 complexes, releases iron ions, leads to iron overload, and induces ferroptosis, which may be an important mechanism for its anti-hepatic fibrosis effect.

Previous studies have suggested strong antifibrotic activity of curcumol in the liver; the underlying mechanisms of which, however, remain largely unknown. Aiming to investigate the role of curcumol in regulating early and advanced liver fibrosis, we designed a rat model with advanced liver fibrosis and cell model with an initial fibrotic stage. Model rats induced by CCl 4 and alcohol presented advanced liver fibrosis with complete fibrous septa. The administration of curcumol (25 mg/kg or 50 mg/kg) resulted in reversal of liver fibrosis. Leptin-administrated liver sinusoidal endothelial cells presented defenestration and basement membrane components deposition, including laminin (LN) and type IV collagen (Col IV), the characteristics of capillarization by scanning electron microscopy and immunofluorescence assays. After treatment with curcumol (12.5, 25, or 50 mg/L), defenestration was restored and the levels of LN and Col IV were decreased, consistent with the rat model. Quantitative polymerase chain reaction and Western blot results revealed that increased levels of urokinase plasminogen activator (uPA)/ uPA receptor (uPAR) were observed both in vivo and in vitro, curcumol significantly reduced uPA/uPAR at both the mRNA and protein levels. Reduction of uPA/uPAR may be synergistic with matrix metallopeptidase 13 to reverse liver fibrogenesis. In conclusion, curcumol protects liver from phenotypic changes in the early and advanced fibrogenesis, possibly through uPA/uPAR pathway.