Emodin (1,3,8‐trihydroxy‐6‐methylanthraquinone), an active component in the root and rhizome of Rheum palmatum, is a tyrosine kinase inhibitor with a number of biological activities, including antitumor effects. Here, we examine the effects of emodin on vascular endothelial growth factor (VEGF)‐A‐induced angiogenesis, both in vitro and in vivo. In vitro, emodin dose‐dependently inhibits proliferation, migration into the denuded area, invasion through a layer of Matrigel and tube formation of human umbilical vein endothelial cells (HUVECs) stimulated with VEGF‐A. Emodin also inhibits basic fibroblast growth factor‐induced proliferation and migration of HUVECs and VEGF‐A‐induced tube formation of human dermal microvascular endothelial cells. Specifically, emodin induces the cell cycle arrest of HUVECs in the G0/G1 phase by suppressing cyclin D1 and E expression and retinoblastoma protein phosphorylation, and suppresses Matrigel invasion by inhibiting the basal secretion of matrix metalloproteinase‐2 and VEGF‐A‐stimulated urokinase plasminogen activator receptor expression. Additionally, emodin effectively inhibits phosphorylation of VEGF‐A receptor‐2 (KDR/Flk‐1) and downstream effector molecules, including focal adhesion kinase, extracellular signal‐regulated kinase 1/2, p38 mitogen‐activated protein kinase, Akt and endothelial nitric oxide synthase. In vivo, emodin strongly suppresses neovessel formation in the chorioallantoic membrane of chick and VEGF‐A‐induced angiogenesis of the Matrigel plug in mice. Our data collectively demonstrate that emodin effectively inhibits VEGF‐A‐induced angiogenesis in vitro and in vivo. Moreover, inhibition of phosphorylation of KDR/Flk‐1 and downstream effector molecules is a possible underlying mechanism of the anti‐angiogenic activity of emodin. Based on these data, we propose that an interaction of emodin with KDR/Flk‐1 may be involved in the inhibitory function of emodin toward VEGF‐A‐induced angiogenesis in vitro and responsible for its potent anti‐angiogenic in vivo. © 2006 Wiley‐Liss, Inc.

The net balance of matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP) system has been known to be a key factor in tumor cell invasion. In the present study, we investigated the molecular mechanisms of anti-invasive and antimigrative activity of transforming growth factor (TGF)-B1 on HT1080 human fibrosarcoma cells. In in vitro Matrigel invasion and Transwell migration assays, TGF-B1 dose-dependently inhibited the invasion and migration of HT1080 cells, respectively. Gelatin zymography, Western blot, and real-time PCR analysis showed that TGF-B1 enhanced the expression and secretion of MMP-2, TIMP-1, and, to a lesser degree, MMP-9 but not membrane type 1-MMP and TIMP-2. The addition of recombinant TIMP-1 protein reduced the Matrigel invasion and Transwell migration of HT1080 cells, similar to TGF-B1. Because augmentation of TIMP-1 might be the major factor for the anti-invasive and antimigrative activity of TGF-B1, we investigated possible molecular mechanisms responsible for the expression of TIMP-1 induced by TGF-B1. Treatment of HT1080 cells with TGF-B1 rapidly phosphorylated three mitogen-activated protein kinases [MAPK; extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun NH 2 -terminal kinase] and Akt. Among these kinases, the inhibition of only ERK1/2 pathway by PD98059, a specific inhibitor of MAPK/ERK kinase(MEK)-1, and transfection of dominant-negative MEK 1 effectively blocked the TIMP-1 induction by TGF-B1. Mithramycin, a specific inhibitor of Sp1 transcription factor, but not curcumin, an inhibitor of activator protein-1, and transfection of Sp1 small interfering RNA significantly inhibited the TGF-B1-induced expression of TIMP-1. In addition, electrophoretic mobility shift assay showed that TGF-B1 up-regulated Sp1 DNA-binding activity, and PD98059 and mithramycin effectively inhibited these events. Finally, pretreatment of HT1080 cells with PD98059 and mithramycin, but not curcumin, restored the invasive activity of these cells. Taken together, these data suggest that TGF-B1 modulates the net balance of the MMPs/TIMPs the systems in HT1080 cells for antiinvasion and antimigration by augmenting TIMP-1 through ERK1/2 pathway and Sp1 transcription factor.

Abstract. Cisplatin is a DNA-damaging chemotherapeutic drug that may have a role in the adjuvant chemotherapy of several solid tumors, such as malignant glioblastoma, and the status of p53 tumor suppressor protein is a critical determinant of cisplatin chemosensitivity. In the present study, we showed the relationship of p53 status and chemosensitivity of cisplatin between two human malignant glioblastoma cell lines, A172 and T98G, harboring wild-type and mutant-type p53, respectively. Cisplatin was found to be more cytotoxic to A172 than T98G cells in a time-and concentration-dependent manner. Cisplatin-induced cytotoxicity manifested as apoptosis, characterized by genomic DNA fragmentation, nuclear condensation and an increase in sub-G1 population. Cisplatin induced the accumulation of p53 and p21 proteins in A172 cells, but not in T98G cells. The introduction of the adenovirus-mediated wild-type p53 gene into T98G cells resulted in the decrease of viability as well as the increase in sub-G1 population with p53 accumulation, activation of caspase-3 protease and release of cytochrome c from the mitochondria. These data strongly suggest that the expression of p53 is essential for the cytotoxic effect of cisplatin in human malignant glioblastoma cells, A172 and T98G, and the introduction of apoptotic signal molecules, such as p53, will be beneficial to achieve chemosensitivity in malignant glioma.

Chemically induced DNA adducts can lead to mutations and cancer. Unfortunately, because common analytical methods (e.g., liquid chromatography-mass spectrometry) require adducts to be digested or liberated from DNA before quantification, information about their positions within the DNA sequence is lost. Advances in nanopore sequencing technologies allow individual DNA molecules to be analyzed at single-nucleobase resolution, enabling us to study the dynamic of epigenetic modifications and exposure-induced DNA adducts in their native forms on the DNA strand. We applied and evaluated the commercially available Oxford Nanopore Technology (ONT) sequencing platform for site-specific detection of DNA adducts and for distinguishing individual alkylated DNA adducts. Using ONT and the publicly available ELIGOS software, we analyzed a library of 15 plasmids containing site-specifically inserted O 6- or N 2-alkyl-2′-deoxyguanosine lesions differing in sizes and regiochemistries. Positions of DNA adducts were correctly located, and individual DNA adducts were clearly distinguished from each other.

Indole-3-carbinol (I3C) has been found to act against several types of cancer, while ultraviolet B (UVB) is known to induce the apoptosis of human melanoma cells. Here, we investigated whether I3C can sensitize G361 human melanoma cells to UVB-induced apoptosis. We examined the effects of combined I3C and UVB (I3C/UVB) at various dosages. I3C (200 microM)/UVB (50 mJ/cm(2)) synergistically reduced melanoma cell viability, whereas I3C (200 microM) or UVB (50 mJ/cm(2)), separately, had little effect on cell viability. DNA fragmentation assays indicated that I3C/UVB induced apoptosis. Further results show that I3C/UVB activates caspase-8, -3, and Bid and causes the cleavage of poly(ADP-ribose) polymerase. Moreover, I3C decreased the expression of the anti-apoptotic protein, Bcl-2, whereas UVB increased the translocation of Bax to mitochondria. Thus, an increased Bax/Bcl-2 ratio by I3C/UVB may result in melanoma apoptosis. In conclusion, our study demonstrated that I3C sensitizes human melanoma cells by down-regulating Bcl-2.

The antimicrobial effect of a novel flavonoid (7-O-butylnaringenin) on Helicobacter pylori 26695, 51, and SS1 strains and its inhibitory effect on the urease activity of the strains were evaluated and compared with those of several natural flavonoids. First, various flavonoids were screened for antimicrobial activities using the paper disc diffusion method. Hesperetin and naringenin showed the strongest antimicrobial effects among the natural flavonoids tested, and thus hesperetin and naringenin were selected for comparison with 7-O-butylnaringenin. The antimicrobial effect of 7-O-butylnaringenin was greater than that of the hesperetin and naringenin. H. pylori 51 was more sensitive to 7-O-butylnaringenin (2 log reduction of colony forming units, p < 0.05) than the other two strains at 200 μM. 7-O-Butylnaringenin also showed the highest inhibitory effect against urease activity of H. pylori. Morphological changes of H. pylori 26695 treated with these flavonoids indicated that both hesperetin and 7-O-butylnaringenin at 200 μM damaged the cell membranes.

We report the structure-activity relationship analyses of 17 linear lipopeptide paenipeptin analogues. Analogues 7, 12, and 17 were more potent than the lead compound. Analogue 17 was active against carbapenem-resistant and polymyxin-resistant pathogens. This compound at 40 μg/mL resulted in 3 log and 2.6 log reductions of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, respectively, in catheter-associated biofilms in vitro. Analogue 17 showed little hemolysis at 32 μg/mL and lysed 11% of red blood cells at 64 μg/mL. Analogues 9 and 16 were nonhemolytic and retained potent P. aeruginosa-specific antimicrobial activity. These two analogues when used alone lacked activity against Acinetobacter baumannii and Klebsiella pneumoniae; however, analogue 9 and 16 at 4 μg/mL decreased the MIC of rifampicin and clarithromycin against the same pathogens from 16 to 32 μg/mL to nanomolar levels (sensitization factor: 2048-8192). Therefore, paenipeptins, alone or in combination with rifampicin or clarithromycin, are promising candidates for treating bacterial infections.

These results indicated that the two-step enzyme hydrolysates of OTF have great potential for use as a food ingredient with antioxidant and anticancer activities. © 2017 Society of Chemical Industry.