The supercritical CO₂ extract from the skin of Bufo bufo gargarizans Cantor blocks hepatitis B virus antigen secretion in HepG2.2.15 cells

Antifibrotic Mechanism of Cinobufagin in Bleomycin-Induced Pulmonary Fibrosis in Mice

Idiopathic pulmonary fibrosis (IPF) is a progressive and usually fatal lung disease that is characterized by fibroblast proliferation and extracellular matrix remodeling, which result in irreversible distortion of the lung's architecture and the formation of focal fibrous hyperplasia. The molecular mechanism by which pulmonary fibrosis develops is not fully understood, and no satisfactory treatment currently exists. However, many studies consider that aberrant activation of TGF-β1 frequently promotes epithelial-mesenchymal transition (EMT) and fibroblast activation in pulmonary fibrosis. Cinobufagin (CBG), a traditional Chinese medicine, has been widely used for long-term pain relief, cardiac stimulation, and anti-inflammatory and local anesthetic treatments. However, its role in pulmonary fibrosis has not yet been established. We investigated the hypothesis that cinobufagin plays an inhibitory role on TGF-β1 signaling using a luciferase-reporter assay. We further explored the effect of cinobufagin on pulmonary fibrosis both in vitro and in vivo. The in vitro experiments showed that cinobufagin suppresses TGF-β1/Smad3 signaling in a dose-dependent manner, attenuates the activation and differentiation of lung fibroblasts and inhibits EMT induced by TGF-β1 in alveolar epithelial cells. The in vivo experiments indicated that cinobufagin significantly alleviates bleomycin-induced collagen deposition and improves pulmonary function. Further study showed that cinobufagin could attenuate bleomycin-induced inflammation and inhibit fibroblast activation and the EMT process in vivo. In summary, cinobufagin attenuates bleomycin-induced pulmonary fibrosis in mice via suppressing inflammation, fibroblast activation and epithelial-mesenchymal transition.

Combination of Cinobufacini and Doxorubicin Increases Apoptosis of Hepatocellular Carcinoma Cells through the Fas- and Mitochondria-Mediated Pathways

Cinobufacini, a traditional Chinese medicine, has been used widely for cancer treatment, such as hepatocellular carcinoma (HCC), sarcoma, and leukemia. Previous studies done by our lab indicated that cinobufacini could suppress HCC cells through mitochondria-mediated and Fas-mediated apoptotic pathways. Here, we use a combination of cinobufacini and doxorubicin to inhibit the growth of HCC cells. The combination group induced more significant apoptosis by affecting proteins and RNA of apoptosis-related elements, such as Bcl-2, Bax, Bid, and cytochrome c. Furthermore, cinobufacini, as a mixture of a number of components, had stronger apoptosis-inducing activity than particular individual components or a simple mixture of a few components. Overall, these results suggested that the combination of cinobufacini and doxorubicin may provide a new strategy for inhibiting the proliferation of HCC cells.

Adenovirus-mediated P311 inhibits TGF-β1-induced epithelial-mesenchymal transition in NRK-52E cells via TGF-β1-Smad-ILK pathway

P311, a highly conserved 8-kDa intracellular protein, has been indicated as an important factor in myofibroblast transformation and in the progression of fibrosis. In the present study, we constructed a recombinant adenovirus vector of p311 (called Ad-P311) and transferred it into rat renal proximal tubular epithelial cells (NRK-52E) to explore the effect of P311 on epithelial-mesenchymal transition (EMT) of NRK-52E cells induced by TGF-β1 and to elucidate its underlying mechanism against EMT. After successfully construction of Ad-P311 and transfer into NRK-52E cells, the proliferation and growth of P311-expressing cells was detected by MTT assay. TGF-β1 was used to induce NRK-52E cells and Western blot analysis was used to examine the EMT markers (E-cadherin and α-smooth muscle actin (α-SMA)), signal transducers (p-Smad2/3 and Smad7). Integrin Linked Kinase (ILK) as a key intracellular mediator that controls TGF-β1-induced-EMT was also assayed by Western blot analysis. The results showed that P311 transfection could significantly inhibit the proliferation and growth of TGF-β1 induced NRK-52E cells. The results also showed that TGF-β1 could induce EMT in NRK-52E cells through Smad-ILK signaling pathway with an increase in α-SMA, pSmad2/3 and ILK expression, and a decrease in E-cadherin and Smad7 expression. However, P311 efficiently blocked Smad-ILK pathway activation and attenuated all these EMT changes induced by TGF-β1. These findings suggest that P311 might be involved in the pathogenesis of renal fibrosis by inhibiting the EMT process via TGF-β1-Smad-ILK pathway. P311 might be a novel target for the control of renal fibrosis and the progression of CKD.