Guiyuan Lv

Curcumin inhibits lung cancer cell migration and invasion through Rac1-dependent signaling pathway

Curcumin, a natural and crystalline compound isolated from the plant Curcuma longa with low toxicity in normal cells, has been shown to protect against carcinogenesis and prevent tumor development. However, little is known about antimetastasis effects and mechanism of curcumin in lung cancer. Rac1 is an important small Rho GTPases family protein and has been widely implicated in cytoskeleton rearrangements and cancer cell migration, invasion and metastasis. In this study, we examined the influence of curcumin on in vitro invasiveness of human lung cancer cells and the expressions of Rac1. The results indicate that curcumin at 10 μM slightly reduced the proliferation of 801D lung cancer cells but showed an obvious inhibitory effect on epidermal growth factor or transforming growth factor β1-induced lung cancer cell migration and invasion. Meanwhile, we demonstrated that the suppression of invasiveness correlated with inhibition of Rac1/PAK1 signaling pathways and matrix metalloproteinase (MMP) 2 and 9 protein expression by combining curcumin treatment with the methods of Rac1 gene silence and overexpression in lung cancer cells. Laser confocal microscope also showed that Rac1-regulated actin cytoskeleton rearrangement may be involved in anti-invasion effect of curcumin on lung cancer cell. At last, through xenograft experiments, we confirmed the connection between Rac1 and the growth and metastasis inhibitory effect of curcumin in vivo. In summary, these data demonstrated that low-toxic levels of curcumin could efficiently inhibit migration and invasion of lung cancer cells through inhibition of Rac1/PAK1 signaling pathway and MMP-2 and MMP-9 expression, which provided a novel insight into the molecular mechanism of curcumin against lung cancer.

Isolation and Identification of an Anti-tumor Component from Leaves of Impatiens balsamina

We have previously shown that ethanol or chloroform extracts of the leaves of Impatiens balsamina (LIB) have anti-tumor activity against the human hepatocellular carcinoma cell line HepG2. The ethanol extracts were separated into five fractions according to polarity. An MTT assay indicated that two of the fractions had anti-tumor activity and that the petroleum ether fraction (PEF) was the most active. But the available quantities of both the PEF and chloroform fractions (CHF) were limited, precluding further study. The chloroform extract (CHE) shared almost all the same spots with the PEF and CHF and was plentiful enough to carry out further separations. Thus, the CHE was further separated into six sub-fractions (CHE1~6) by column chromatography. A MTT assay showed that only the CHE2 fraction had a strong tumor inhibition ratio (IC50 = 6.47±0.05 mg/L), which was superior to that of curcumin (IC50 = 13.95±0.11 mg/L). However, TLC revealed that CHE2 was not pure and still contained two more components. After further separation and purification, followed by TLC and MTT assay confirmation, the final active component was isolated and identified as 2-methoxy-1,4-naphthoquinone by m.p., UV, MS and 13C- and 1H-NMR data. This is the first report demonstrating that 2-methoxy-1,4-naphthoquinone has intensive in vitro anti-tumor activity against HepG2 cells.

Ginseng saponin metabolite 20(S)-protopanaxadiol inhibits tumor growth by targeting multiple cancer signaling pathways

Plant-derived active constituents and their semi-synthetic or synthetic analogs have served as major sources of anticancer drugs. 20(S)-protopanaxadiol (PPD) is a metabolite of ginseng saponin of both American ginseng (Panax quinquefolius L.) and Asian ginseng (Panax ginseng C.A. Meyer). We previously demonstrated that ginsenoside Rg3, a glucoside precursor of PPD, exhibits anti-proliferative effects on HCT116 cells and reduces tumor size in a xenograft model. Our subsequent study indicated that PPD has more potent antitumor activity than that of Rg3 in vitro although the mechanism underlying the anticancer activity of PPD remains to be defined. Here, we investigated the mechanism underlying the anticancer activity of PPD in human cancer cells in vitro and in vivo. PPD was shown to inhibit growth and induce cell cycle arrest in HCT116 cells. The in vivo studies indicate that PPD inhibits xenograft tumor growth in athymic nude mice bearing HCT116 cells. The xenograft tumor size was significantly reduced when the animals were treated with PPD (30 mg/kg body weight) for 3 weeks. When the expression of previously identified Rg3 targets, A kinase (PRKA) anchor protein 8 (AKAP8L) and phosphatidylinositol transfer protein α (PITPNA), was analyzed, PPD was shown to inhibit the expression of PITPNA while upregulating AKAP8L expression in HCT116 cells. Pathway-specific reporter assays indicated that PPD effectively suppressed the NF-κB, JNK and MAPK/ERK signaling pathways. Taken together, our results suggest that the anticancer activity of PPD in colon cancer cells may be mediated through targeting NF-κB, JNK and MAPK/ERK signaling pathways, although the detailed mechanisms underlying the anticancer mode of PPD action need to be fully elucidated.

Tetrandrine Suppresses Cancer Angiogenesis and Metastasis in 4T1 Tumor Bearing Mice

Metastasis remains the most deadly aspect of cancer and still evades direct treatment. Thus, there is a great need to develop new treatment regimens to suppress tumor cells that have escaped surgical removal or that may have already disseminated. We have found that tetrandrine (TET) exhibits anticolon cancer activity. Here, we investigate the inhibition effect of TET to breast cancer metastasis, angiogenesis and its molecular basis underlying TETs anticancer activity. We compare TET with chemotherapy drug doxorubicin in 4T1 tumor bearing BALB/c mice model and find that TET exhibits an anticancer metastatic and antiangiogenic activities better than those of doxorubicin. The lung metastatic sites were decreased by TET, which is confirmed by bioluminescence imaging in vivo. On the other hand, laser doppler perfusion imaging (LDI) was used for measuring the blood flow of tumor in 4T1-tumor bearing mice. As a result, the local blood perfusion of tumor was markedly decreased by TET after 3 weeks. Mechanistically, TET treatment leads to a decrease in p-ERK level and an increase in NF-κB levels in HUVECs. TET also regulated metastatic and angiogenic related proteins, including vascular endothelial growth factor, hypoxia-inducible factor-1α, integrin β5, endothelial cell specific molecule-1, and intercellular adhesion molecule-1 in vivo.

Antitumor constituents from the leaves of Carya cathayensis

This study aimed to find cytotoxic chemical constituents from Carya cathayensis leaves (LCC) by using various chromatographic procedures. Identification of the chemical constituents was carried out by various spectroscopic techniques and classical chemical methods. The cytotoxic activity of the constituents was assayed on HeLa and HepG2 cell lines by staining with 3-(4,5-dimethylthiahiazol-2-y1)-2,5-di-phenytetrazolium bromide (MTT). Six flavanoids, namely (1) pinostrobin, (2) pinostrobin chalcone, (3) wogonin, (4) cardamonin, (5) alpinetin and (6) tectochrysin were identified from this species. Compounds 2–6 were isolated from this kind of plant for the first time. MTT results showed that wogonin has a moderate cytotoxic activity with IC50 values of 17.03 ± 2.41 and 44.23 ± 3.87 µM against HeLa and HepG2 cell lines, respectively. According to the correlation of primary the structure and activity, 8-methoxy substituent in these flavones may be a major factor of the antitumor activity.

Pharmacokinetic profile of 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside in mice after oral administration of Polygonum multiflorum extract.

Context: Stilbene glycoside (2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside) is a main bioactive component of Polygonum multiflorum, a traditional Chinese medicine (TCM) commonly used in clinic for anti-aging treatment. Its medicinal activities, such as anti-oxidation, anti-inflammation and endothelial protection, have been extensively studied, but its pharmacokinetic property is still unclear. Objective: A pharmacokinetic study was undertaken to quantitatively determine P. multiflorum stilbene glycoside (PM-SG) in mouse plasma after oral administration of 100 mg/kg P. multiflorum extract. Materials and methods: A sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with liquid-liquid phase extraction method was employed for this study. Pharmacokinetic parameters of PM-SG were determined in mice applying both compartmental and non-compartmental analyses. Results and discussion: The calibration curve for PM-SG in the plasma was linear (r2 > 0.99) over the range of 0.66 to 56.40 μg/ml, and the concentration-time curve was plotted with the maximum concentration (Cmax) and time to reach maximum concentration (Tmax) of 29.62 μg/ml and 60 min, respectively. The intra- and inter-day variations were less than 3% for relative standard deviation (RSD) and relative error (RE), with a good recovery of more than 97% (RSD <3%). All pharmacokinetic parameters estimated by compartmental and non-compartmental models reached a same conclusion that PM-SG was rapidly absorbed and widely distributed throughout the body with a great efficiency of utility, followed by quick elimination and clearance. Conclusions: This was the first report on determination of the pharmacokinetic profile of PM-SG in mice after oral administration. The result may provide a meaningful basis for evaluating the clinical applications of such a bioactive compound from herbal medicines.

Luteolin Ameliorates Hypertensive Vascular Remodeling through Inhibiting the Proliferation and Migration of Vascular Smooth Muscle Cells

Objectives. Preliminary researches showed that luteolin was used to treat hypertension. However, it is still unclear whether luteolin has effect on the hypertensive complication such as vascular remodeling. The present study was designed to investigate the effect of luteolin on the hypertensive vascular remodeling and its molecular mechanism. Method and Results. We evaluated the effect of luteolin on aorta thickening of hypertension in spontaneous hypertensive rats (SHRs) and found that luteolin could significantly decrease the blood pressure and media thickness of aorta in vivo. Luteolin could inhibit angiotensin II- (Ang II-) induced proliferation and migration of vascular smooth muscle cells (VSMCs). Dichlorofluorescein diacetate (DCFH-DA) staining result showed that luteolin reduced Ang II-stimulated ROS production in VSMCs. Furthermore, western blot and gelatin zymography results showed that luteolin treatment leaded to a decrease in ERK1/2, p-ERK1/2, p-p38, MMP2, and proliferating cell nuclear antigen (PCNA) protein level. Conclusion. These data support that luteolin can ameliorate hypertensive vascular remodeling by inhibiting the proliferation and migration of Ang II-induced VSMCs. Its mechanism is mediated by the regulation of MAPK signaling pathway and the production of ROS.

Label-free and sensitive fluorescent detection of sequence-specific single-strand DNA based on S1 nuclease cleavage effects.

The ability to detect sequence-specific single-strand DNA (ssDNA) in complex, contaminant-ridden samples, using a fluorescent method directly without a DNA extraction and PCR step could simplify the detection of pathogens in the field and in the clinic. Here, we have demonstrated a simple label-free sensing strategy to detect ssDNA by employing its complementary ssDNA, S1 nuclease and nucleic acid fluorescent dyes. Upon clearing away redundant complementary ssDNA and possibly mismatched double strand DNA by using S1 nuclease, the fluorescent signal-to-noise ratio could be increased dramatically. It enabled the method to be adaptable to three different types of DNA fluorescent dyes and the ability to detect target ssDNA in complex, multicomponent samples, like tissue homogenate. The method can distinguish a two-base mismatch from avian influenza A (H1N1) virus. Also, it can detect the appearance of 50 pM target ssDNA in 0.5 µg·mL−1 Lambda DNA, and 50 nM target ssDNA in 5 µg·mL−1 Lambda DNA or in tissue homogenate. It is facile and cost-effective, and could be easily extended to detect other ssDNA with many common nucleic acid fluorescent dyes.

Hypoxia pathway and hypoxia-mediated extensive extramedullary hematopoiesis are involved in ursolic acid's anti-metastatic effect in 4T1 tumor bearing mice.

Hypoxic in the tumor mass is leading to the myeloproliferative-like disease (leukemoid reaction) and anemia of body, which characterized by strong extensive extramedullary hematopoiesis (EMH) in spleen. As the key transcription factor of hypoxia, hypoxia-inducible factor-1 (HIF-1) activates the expression of genes essential for EMH processes including enhanced blood cell production and angiogenesis. We found ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid, inhibited growth of breast cancer both in vivo and in vitro. The suppression was mediated through the inhibition of multiple cell pathways linked to inflammation, proliferation, angiogenesis, and metastasis. UA also suppressed the leukemoid reaction and the EMH phenomenon of the tumor bearing mice without any significant suppression on body weight (i.p. by 20 mg/kg for 28 days). This is associated with the significant decrease in white blood cells (WBC), platelets (PLT) and spleen weight. During this process, we also detected the down-regulation of cell proliferative genes (PCNA, and β-catenin), and metastatic genes (VEGF, and HIF-1α), as well as the depression of nuclear protein intensity of HIF-1α. Furthermore, the expression of E2F1, p53 and MDM2 genes were increased in UA group when the VEGF and HIF-1α was over-expressed. Cancer cells were sensitive to UA treating after the silencing of HIF-1α and the response of Hypoxic pathway reporter to UA was suppressed when HIF-1α was over expressed. Overall, our results from experimental and predictive studies suggest that the anticancer activity of UA may be at least in part caused by suppressing the cancer hypoxia and hypoxia-mediated EMH.

Effects of an Enriched Extract of Paeoniflorin, a Monoterpene Glycoside used in Chinese Herbal Medicine, on Cholesterol Metabolism in a Hyperlipidemic Rat Model

Background Paeoniflorin is a monoterpene glycoside extracted from the roots of Paeonia lactiflora and is used in Chinese herbal medicine to treat hyperlipidemia. The aim of this study was to evaluate the effects of an enriched extract of paeoniflorin on cholesterol levels, hemodynamics, and oxidative stress in a hyperlipidemic rat model. Material/Methods Male Sprague-Dawley rats were fed high-cholesterol diets and treated with three different doses of paeoniflorin for 12 weeks. The effects of paeoniflorin treatment were assessed on cholesterol levels, cholesterol metabolism, red blood cell vascular flow using hemorheology, antioxidant enzymes, and expression of the rate-limiting enzyme in the mevalonate pathway, 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMG-CoAR). Rat liver histology and immunohistochemical analysis were performed to evaluate the expression of nuclear factor erythroid 2–related factor 2 (Nrf2), cytochrome P450 7A1 (CYP7A1), and peroxisome proliferator-activated receptors (PPAR)-α. Protein expression HMG-CoAR, low-density lipoprotein receptor (LDLR), PPAR-α and CYP7A1 was measured by Western blotting. Antioxidant activity in rat liver was determined by measuring superoxide dismutase (SOD) and malondialdehyde (MDA). Results Serum and hepatic cholesterol, hepatic steatosis and the products of cholesterol metabolism were reduced by paeoniflorin treatment, which also reduced the activity of HMG-CoAR and upregulated the expression of LDLR, PPAR-α, and CYP7A1 expression, increased SOD, decreased MDA, and upregulated Nrf2 expression. Conclusions The findings of this study in a rat model of hyperlipidemia have shown that paeoniflorin regulates hepatic cholesterol synthesis and metabolism and may also protect the liver from oxidative stress.