Activated Hepatic Stellate Cells (HSCs), major fibrogenic cells in the liver, undergo apoptosis when liver injuries cease, which may contribute to the resolution of fibrosis. Bisdemethoxycurcumin (BDMC) is a natural derivative of curcumin with anti-inflammatory and anti-cancer activities. The therapeutic potential of BDMC in hepatic fibrosis has not been studied thus far in the context of the apoptosis in activated HSCs. In the current study, we compared the activities of BDMC and curcumin in the HSC-T6 cell line and demonstrated that BDMC relatively induced a potent apoptosis. BDMC-induced apoptosis was mediated by a combinatory inhibition of cytoprotective proteins, such as Bcl2 and heme oxygenase-1 and increased generation of reactive oxygen species. Intriguingly, BDMC-induced apoptosis was reversed with co-treatment of sr144528, a cannabinoid receptor (CBR) 2 antagonist, which was confirmed with genetic downregulation of the receptor using siCBR2. Additionally, incubation with BDMC increased the formation of death-induced signaling complex in HSC-T6 cells. Treatment with BDMC significantly diminished total intracellular ATP levels and upregulated ATP inhibitory factor-1. Collectively, the results demonstrate that BDMC induces apoptosis in activated HSCs, but not in hepatocytes, by impairing cellular energetics and causing a downregulation of cytoprotective proteins, likely through a mechanism that involves CBR2.

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Hepatic stellate cells (HSCs) are involved in the pathogenesis of liver fibrosis. Resveratrol, 3,5,4′-trihydroxystilbene, is a dietary polyphenol found in natural food products. Here, we evaluated the anti-proliferative effects of a synthetic resveratrol derivative, 3,5-diethoxy-3′-hydroxyresveratrol (DEHR), on HSCs. Flow cytometry and Western blot analyses showed that DEHR induces apoptosis through the upregulation of cleaved caspase-3 and poly (ADP-ribose) polymerase expression and reduction in the level of an anti-apoptotic protein B-cell lymphoma 2 (Bcl2). As caveolin-1 (CAV1), a competitive inhibitor of heme oxygenase 1 (HO-1), is related to apoptotic proteins in hepatic cells, we focused on the role of CAV1 in DEHR-induced apoptosis in HSCs through Western blot analyses. Our results showed that the inhibitory effect of DEHR on cell viability was stronger in HO-1 siRNA-transfected cells but weakened in CAV1 siRNA-transfected cells. Collagen concentration was significantly reduced, whereas CAV1 expression increased after treatment of a bile duct ligation injury-induced liver fibrosis model with DEHR for four weeks. We confirmed that DEHR treatment significantly reduced fibrous hyperplasia around the central veins, using hematoxylin and eosin and Sirius red staining. DEHR ameliorates liver fibrosis in vitro and in vivo, possibly through a mechanism involving CAV1.

Deuterium oxide (D2O) has been reported to be active toward various in vitro cell lines in combination with phytochemicals. Our objective was to describe, for the first time, the effect of D2O on the proliferation of hepatic stellate cells (HSCs). After D2O treatment, the p53-cyclin-dependent kinase (CDK) pathway was stimulated, leading to inhibition of the proliferation of HSCs and an increase in the [ATP]/[ADP] ratio. We also evaluated the role of aquaporin (AQP) 11 in activated HSCs. We found that D2O treatment decreased AQP11 expression levels. Of note, AQP11 levels elevated by a genetic approach counteracted the D2O-mediated inhibition of proliferation. In addition, the expression levels of AQP11 negatively correlated with those of p53. On the other hand, cells transfected with an AQP11-targeted small interfering RNA (siRNA) showed enhanced inhibition of proliferation. These findings suggest that the inhibition of cell proliferation by D2O in activated HSCs could be AQP11 dependent. Our previous studies have documented that bisdemethoxycurcumin (BDMC) induces apoptosis by regulating heme oxygenase (HO)-1 protein expression in activated HSCs. In the current study, we tested whether cotreatment with BDMC and D2O can modulate the AQP11-dependent inhibition of cell proliferation effectively. We observed that D2O cotreatment with BDMC significantly decreased cell proliferation compared to treatment with D2O alone, and this effect was accompanied by downregulation of HO-1 and an increase in p53 levels.

Spatholobus suberectus Dunn (SSD) possesses potential antitumor activity; however, the mechanism underlying its anti-proliferative effect on breast cancer is unclear. In this study, we explored potential SSD targets for breast cancer treatment through a network pharmacology approach. First, by integrating multiple databases, a total of 16 potential bioactive compounds and 252 targets were screened. Differentially expressed genes (DEGs) were screened by analyzing breast cancer gene chip data from The Cancer Genome Atlas and Gene Expression Omnibus databases. By overlapping drug targets and DEGs, 33 common targets were found; their functions were further analyzed with Gene Ontology and KEGG analysis. A network of 16 compounds and 33 common targets was constructed, from which 10 hub targets were identified using CytoHubba. Based on the KEGG result and network analysis, the 33 common targets were mainly enriched in the peroxisome proliferator-activated receptor (PPAR) signaling pathway and PPARγ was identified as the potential target of SSD. Moreover, the 10 hub targets were correlated with prognosis and immune infiltration in breast cancer via bioinformatic analysis. Finally, molecular docking and experiments in vitro further verified the targeting ability and anti-breast cancer activity of SSD. SSD is promising in the treatment of breast cancer; PPARγ may be its potential therapeutic target.