(+)-Isobicyclogermacrenal and spathulenol from Aristolochia yunnanensis alleviate cardiac fibrosis by inhibiting transforming growth factor ß/small mother against decapentaplegic signaling pathway.

Cardiac fibrosis contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. Antifibrotic therapies are likely to be a crucial strategy in curbing many fibrosis-related cardiac diseases. In our previous study, an ethyl acetate extract of a traditional Chinese medicine Aristolochia yunnanensis Franch. was found to have a therapeutic effect on myocardial fibrosis in vitro and in vivo. However, the exact chemicals and their mechanisms responsible for the activity of the crude extract have not been illustrated yet. In the current study, 10 sesquiterpenoids (1-10) were isolated from the active extract, and their antifibrotic effects were systematically evaluated in transforming growth factor ß 1 (TGFß1)-stimulated cardiac fibroblasts and NIH3T3 fibrosis models. (+)-Isobicyclogermacrenal (1) and spathulenol (2) were identified as the main active components, being more potent than the well-known natural antifibrotic agent oxymatrine. Compounds 1 and 2 could inhibit the TGFß1-induced cardiac fibroblasts proliferation and suppress the expression of the fibrosis biomarkers fibronectin and α-smooth muscle actin via down-regulation of their mRNA levels. The mechanism study revealed that 1 and 2 could inhibit the phosphorylation of TGFß type I receptor, leading to the decrease of the phosphorylation levels of downstream Smad2/3, then consequently blocking the nuclear translocation of Smad2/3 in the TGFß/Smad signaling pathway. These findings suggest that 1 and 2 may serve as promising natural leads for the development of anticardiac fibrosis drugs.

Identification of potential pathways involved in the induction of cell cycle arrest and apoptosis by a new 4-arylidene curcumin analogue T63 in lung cancer cells: a comparative proteomic analysis.

Curcumin (diferuloylmethane) is a polyphenol natural product of the plant Curcuma longa, and has a diversity of antitumor activities. However, the clinical application of curcumin remains limited due to its poor pharmacokinetic characteristics. It is therefore critical to develop structural analogues of curcumin with increasing anticancer activity. T63, a new 4-arylidene curcumin analogue, was synthesized in our previous studies and exhibited higher in vitro and in vivo anti-tumor activities compared to curcumin. However, the precise molecular mechanism of its anti-tumor effects has not been well elucidated. Using a two-dimensional gel electrophoresis (2-DE)-based proteomic approach, we identified 66 differentially expressed proteins. Similarly to curcumin, T63 showed a diverse range of molecular targets. We proposed that induction of ROS generation and mitochondrial dysfunction, inhibition of proteasome, HSP90, and 14-3-3 proteins play important roles in T63-induced cell cycle arrest and apoptosis. These data indicate that the novel curcumin analogue T63 is a potent anti-tumor agent, which can induce cell cycle arrest and apoptosis, and also provided valuable resources for further study of the anti-tumor effects and molecular mechanisms of T63.

Epithelial-mesenchymal transition (EMT) induced by TNF-α requires AKT/GSK-3ß-mediated stabilization of snail in colorectal cancer.

Chronic inflammation-promoted metastasis has been considered as a major challenge in cancer therapy. Pro-inflammatory cytokine TNFα can induce cancer invasion and metastasis associated with epithelial-mesenchymal transition (EMT). However, the underlying mechanisms are not entirely clear. In this study, we showed that TNFα induces EMT in human HCT116 cells and thereby promotes colorectal cancer (CRC) invasion and metastasis. TNFα-induced EMT was characterized by acquiring mesenchymal spindle-like morphology and increasing the expression of N-cadherin and fibronectin with a concomitant decrease of E-cadherin and Zona occludin-1(ZO-1). TNFα treatment also increased the expression of transcription factor Snail, but not Slug, ZEB1 and Twist. Overexpression of Snail induced a switch from E-cadherin to N-cadherin expression in HCT116 cells, which is a characteristic of EMT. Conversely, knockdown of Snail significantly attenuated TNFα-induced EMT in HCT116 cells, suggesting that Snail plays a crucial role in TNFα-induced EMT. Interestingly, exposure to TNFα rapidly increased Snail protein expression and Snail nuclear localization but not mRNA level upregulation. Finally, we demonstrated that TNFα elevated Snail stability by activating AKT pathway and subsequently repressing GSK-3ß activity and decreasing the association of Snail with GSK-3ß. Knockdown of GSK-3ß further verified our finding. Taken together, these results revealed that AKT/GSK-3ß-mediated stabilization of Snail is required for TNFα-induced EMT in CRC cells. Our study provides a better understanding of inflammation-induced CRC metastasis.

T63, a new 4-arylidene curcumin analogue, induces cell cycle arrest and apoptosis through activation of the reactive oxygen species-FOXO3a pathway in lung cancer cells.

Curcumin (diferuloylmethane) is a natural polyphenol product of the plant Curcuma longa and has a diversity of antitumor activities. T63, a new 4-arylidene curcumin analogue, was reported to inhibit proliferation of lung cancer cells. However, its precise molecular antitumor mechanisms have not been well elucidated. Here, we showed that T63 could significantly inhibit the proliferation of A549 and H460 human lung cell lines via induction of G0/G1 cell cycle arrest and apoptosis. We found that the reactive oxygen species (ROS)-activated FOXO3a cascade plays a central role in T63-induced cell proliferation inhibition. Mechanistically, enhancement of ROS production by T63 induced FOXO3a expression and nuclear translocation through activation of p38MAPK and inhibition of AKT, subsequently elevating the expression of FOXO3a target genes, including p21, p27, and Bim, and then increased the levels of activated caspase-3 and decreased the levels of cyclin D1. Moreover, the antioxidant N-acetylcysteine markedly blocked the above effects, and small interfering RNA-mediated knockdown of FOXO3a also significantly decreased T63-induced cell cycle arrest and apoptosis. In vivo experiments showed that T63 significantly suppressed the growth of A549 lung cancer xenograft tumors, associated with proliferation suppression and apoptosis induction in tumor tissues, without inducing any notable major organ-related toxicity. These data indicated that the novel curcumin analogue T63 is a potent antitumor agent that induces cell cycle arrest and apoptosis and has significant therapeutic potential for lung cancer.