Green tea catechins have been extensively studied for their cancer preventive effects. Accumulating evidence has shown that green tea catechins, like (-)-epigallocatechin-3-gallate, have strong anti-oxidant activity and affect several signal transduction pathways relevant to cancer development. Here, we review the biological properties of green tea catechins and the molecular mechanisms of their anticancer effects, including the suppression of cancer cell proliferation, induction of apoptosis, and inhibition of tumor metastasis and angiogenesis. We summarize the efficacy of a single catechin and the synergetic effects of multiple catechins. We also discuss the enhanced anticancer effects of green tea catechins when they are combined with anticancer drugs. The information present in this review might promote the development of strategy for the co-administration of green tea catechins with other anticancer drugs to increase the potency of currently available anticancer medicine. This new strategy should in turn lower the cytotoxicity and cost of anticancer treatment.
Mangiferin, a xanthonoid found in plants including mangoes and iris unguicularis, was suggested in previous studies to have anti-hyperglycemic function, though the underlying mechanisms are largely unknown. This study was designed to determine the therapeutic effect of mangiferin by the regeneration of β-cells in mice following 70% partial pancreatectomy (PPx), and to explore the mechanisms of mangiferin-induced β-cell proliferation. For this purpose, adult C57BL/6J mice after 7–14 days post-PPx, or a sham operation were subjected to mangiferin (30 and 90 mg/kg body weight) or control solvent injection. Mangiferin-treated mice exhibited an improved glycemia and glucose tolerance, increased serum insulin levels, enhanced β-cell hyperplasia, elevated β-cell proliferation and reduced β-cell apoptosis. Further dissection at the molecular level showed several key regulators of cell cycle, such as cyclin D1, D2 and cyclin-dependent kinase 4 (Cdk4) were significantly up-regulated in mangiferin-treated mice. In addition, critical genes related to β-cell regeneration, such as pancreatic and duodenal homeobox 1 (PDX-1), neurogenin 3 (Ngn3), glucose transporter 2 (GLUT-2), Forkhead box protein O1 (Foxo-1), and glucokinase (GCK), were found to be promoted by mangiferin at both the mRNA and protein expression level. Thus, mangiferin administration markedly facilitates β-cell proliferation and islet regeneration, likely by regulating essential genes in the cell cycle and the process of islet regeneration. These effects therefore suggest that mangiferin bears a therapeutic potential in preventing and/or treating the diabetes.
Polygonatum odoratum lectin (POL), isolated from traditional Chinese medicine herb (Mill.) Druce, has drawn rising attention due to its wide biological activities. In the present study, anti-tumor effects, including apoptosis- and autophagy-inducing properties of POL, were determined by a series of cell biology methods such as MTT, cellular morphology observation, flow cytometry, immunoblotting. Herein, we found that POL could simultaneously induce apoptosis and autophagy in human non-small cell lung cancer A549 cells. POL initiated apoptosis through inhibiting Akt-NF-κB pathway, while POL triggered autophagy via suppressing Akt-mTOR pathway, suggesting the molecular switch role of Akt in regulating between POL-induced apoptosis and autophagy. Moreover, ROS was involved in POL-induced inhibition of Akt expression, and might therefore mediate both apoptosis and autophagy in A549 cells. In addition, POL displayed no significant cytotoxicity toward normal human embryonic lung fibroblast HELF cells. Due to the anti-tumor activities, POL might become a potent anti-cancer drug in future therapy, which might pave the way for exploring GNA-related lectins into effective drugs in cancer treatment.
Taken together, all these findings might hopefully facilitate discovery of new kinase inhibitors that could be promising candidates for anti-cancer drug development.
Estrogen receptor (ER)-α has long been a potential target in ER-α-positive breast cancer therapeutics. In this study, we integrated ER-α-related bioinformatic data at different levels to systematically explore the mechanistic and therapeutic implications of ER-α. Firstly, we identified ER-α-interacting proteins and target genes of ER-α-regulating microRNAs (miRNAs), and analyzed their functional gene ontology (GO) annotations of those ER-α-associated proteins. In addition, we predicted ten consensus miRNAs that could target ER-α, and screened candidate traditional Chinese medicine (TCM) compounds that might hit diverse conformations of ER-α ligand binding domain (LBD). These findings may help to uncover the mechanistic implications of ER-α in breast cancer at a systematic level, and provide clues of miRNAs- and small molecule modulators- based strategies for future ER-α-positive breast cancer therapeutics.
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