Eurycomanone suppresses expression of lung cancer cell tumor markers, prohibitin, annexin 1 and endoplasmic reticulum protein 28

Bioactive compounds from the medicinal plant, Eurycoma longifolia Jack have been shown to promote anti-proliferative effects on various cancer cell lines. Here we examined the effects of purified eurycomanone, a quassinoid found in Eurycoma longifolia Jack extract, on the expression of selected genes of the A549 lung cancer cells. Eurycomanone inhibited A549 lung cancer cell proliferation in a dose-dependent manner at concentrations ranging from 5 to 20 μg/ml. The concentration that inhibited 50% of cell growth (GI₅₀) was 5.1 μg/ml. The anti-proliferative effects were not fully reversible following the removal of eurycomanone, in which 30% of cell inhibition still remained (p < 0.0001, T-test). At 8 μg/ml (GI₇₀), eurycomanone suppressed anchorage-independent growth of A549 cells by >25% (p < 0.05, T-test, n = 8) as determined using soft agar colony formation assay. Cisplatin, a chemotherapy drug used for the treatment of non small cell lung cancer on the other hand, inhibited A549 cells proliferation at concentrations ranging from 0.2 μg/ml to 15 μg/ml with a GI₅₀ of 0.58 μg/ml. The treatment with eurycomanone reduced the abundance expression of the lung cancer markers, heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, p53 tumor suppressor protein and other cancer-associated genes including prohibitin (PHB), annexin 1 (ANX1) and endoplasmic reticulum protein 28 (ERp28) but not the house keeping genes. The mRNA expressions of all genes with the exception of PHB were significantly downregulated, 72 h after treatment (p < 0.05, T-test, n = 9). These findings suggest that eurycomanone at viable therapeutic concentrations of 5-20 μg/ml exhibited significant anti-proliferative and anti-clonogenic cell growth effects on A549 lung cancer cells. The treatment also resulted in suppression of the lung cancer cell tumor markers and several known cancer cell growth-associated genes.     

Conducting an acute intense interval exercise session during the ramadan fasting month: what is the optimal time of the day?

This study examines the effects of Ramadan fasting on performance during an intense exercise session performed at three different times of the day, i.e., 08:00, 18:00, and 21:00?h. The purpose was to determine the optimal time of the day to perform an acute high-intensity interval exercise during the Ramadan fasting month. After familiarization, nine trained athletes performed six 30-s Wingate anaerobic test (WAnT) cycle bouts followed by a time-to-exhaustion (T(exh)) cycle on six separate randomized and counterbalanced occasions. The three time-of-day nonfasting (control, CON) exercise sessions were performed before the Ramadan month, and the three corresponding time-of-day Ramadan fasting (RAM) exercise sessions were performed during the Ramadan month. Note that the 21:00?h session during Ramadan month was conducted in the nonfasted state after the breaking of the day's fast. Total work (TW) completed during the six WAnT bouts was significantly lower during RAM compared to CON for the 08:00 and 18:00?h (p?相似文献   

Steady-state kinetics and inhibitory action of antitubercular phenothiazines on mycobacterium tuberculosis type-II NADH-menaquinone oxidoreductase (NDH-2)

Type-II NADH-menaquinone oxidoreductase (NDH-2) is an essential respiratory enzyme of the pathogenic bacterium Mycobacterium tuberculosis (Mtb) that plays a pivotal role in its growth. In the present study, we expressed and purified highly active Mtb NDH-2 using a Mycobacterium smegmatis expression system, and the steady-state kinetics and inhibitory actions of phenothiazines were characterized. Purified NDH-2 contains a non-covalently bound flavin adenine dinucleotide cofactor and oxidizes NADH with quinones but does not react with either NADPH or oxygen. Ubiquinone-2 (Q2) and decylubiquinone showed high electron-accepting activity, and the steady-state kinetics and the NADH-Q2 oxidoreductase reaction were found to operate by a ping-pong reaction mechanism. Phenothiazine analogues, trifluoperazine, Compound 1, and Compound 2 inhibit the NADH-Q2 reductase activity with IC50 = 12, 11, and 13 microm, respectively. Trifluoperazine inhibition is non-competitive for NADH, whereas the inhibition kinetics is found to be uncompetitive in terms of Q2.     

A decade of belowground reorganization following multiple disturbances in a subtropical wet forest

Humid tropical forests are dynamic ecosystems that experience multiple and overlapping disturbance events that vary in frequency, intensity, and spatial extent. Here we report the results of a 10-year study investigating the effects of forest clearing and multiple hurricanes on ecosystem carbon reservoirs, nutrient pools and vegetation. The aboveground plant community was most heavily affected by multiple disturbances, with the 9-year-old stands showing high rates of hurricane-induced mortality relative to surrounding forest. Belowground pools were less affected. Live fine root biomass fluctuated in response to multiple disturbances, but returned to pre-disturbance levels after 10 years. Soil C was resilient to clearing and hurricanes, probably due to the large pool size and high clay content. Soil P fluctuated over time, declining during periods of rapid plant recovery and growth. With the exception of K, base cations recovered within 2 years following clearing and showed little response to hurricane disturbance.     

Surface Temperature Distribution of a Breast With and Without Tumour

Breast cancer is a common and dreadful disease in women. Regular screening helps in its early detection. At present the most common methods of screening are by self examination and mammography. The surface temperature distribution of the breast can also provide some information on the presence of tumour. This distribution has a relation to the size and location of tumour and can be seen using thermography, where the infrared radiation emitted from the surface of the breast is recorded and a thermal pattern obtained. Thermography is a non-invasive and an inexpensive tool which could be used for early detection. In order to simulate the surface temperature distribution, a two-dimensional model of female breast with and without a carcinoma is considered. The breast is modelled with varying layer thickness close to the actual shape and numerically solved using finite element analysis. Temperature profiles are obtained for a normal breast and for a malignant one by varying the tumour size, location and the blood flow rates. The results show that the surface temperature for a malignant breast is higher than that of a normal one. In addition the size and location of the tumour do have an effect on the surface temperature distribution. It can also be seen that tumour of different sizes placed at the same location would yield the same maximum temperature depending on the blood perfusion rate.     

Structural characterization of the N-terminal autoregulatory sequence of phenylalanine hydroxylase

Phenylalanine hydroxylase (PAH) is activated by its substrate phenylalanine, and through phosphorylation by cAMP-dependent protein kinase at Ser16 in the N-terminal autoregulatory sequence of the enzyme. The crystal structures of phosphorylated and unphosphorylated forms of the enzyme showed that, in the absence of phenylalanine, in both cases the N-terminal 18 residues including the phosphorylation site contained no interpretable electron density. We used nuclear magnetic resonance (NMR) spectroscopy to characterize this N-terminal region of the molecule in different stages of the regulatory pathway. A number of sharp resonances are observed in PAH with an intact N-terminal region, but no sharp resonances are present in a truncation mutant lacking the N-terminal 29 residues. The N-terminal sequence therefore represents a mobile flexible region of the molecule. The resonances become weaker after the addition of phenylalanine, indicating a loss of mobility. The peptides corresponding to residues 2-20 of PAH have different structural characteristics in the phosphorylated and unphosphorylated forms, with the former showing increased secondary structure. Our results support the model whereby upon phenylalanine binding, the mobile N-terminal 18 residues of PAH associate with the folded core of the molecule; phosphorylation may facilitate this interaction.     

Angiopoietin 1 promotes tumor angiogenesis and tumor vessel plasticity of human cervical cancer in mice

We have previously shown that following psoralen photoactivation (PUVA treatment) human dermal fibroblasts undergo long-term growth arrest as well as morphological and functional changes reminiscent of cellular senescence [ 1 ]. In the absence of molecular data on what constitutes normal senescence, it has been difficult to decide whether these PUVA-induced changes reflect cellular senescence or rather a mimic thereof. We herein report that PUVA-induced growth arrest, the senescent phenotype with long-term induction of senescence-associated beta-galactosidase, as well as increased expression of matrix metalloprotease-1 are fully reversible at days 100 to 130 post PUVA treatment in four independently tested fibroblast strains. The late returning growth capacity in PUVA-treated fibroblasts is not due to immortalization, as shown by continued lack of telomerase activity, accelerated telomere shortening, and a decrease in overall growth rates in fibroblasts in their regrowing phase post PUVA treatment. Lack of anchorage-independent growth additionally suggests that the cells are also not tumorigenically transformed. Collectively, our data suggest that PUVA-induced changes do not fully reflect replicative senescence but rather represent a long-term transient phenocopy of senescence. The model reported here is particularly suited to elucidating mechanisms underlying long-term transient growth arrest, the related functional changes, and the release of cells thereof.     

Angiopoietin 1 Promotes Tumor Angiogenesis and Tumor Vessel Plasticity of Human Cervical Cancer in Mice

Angiopoietins have been increasingly implicated to play important roles in blood vessel formation, remodeling, maturation, and maintenance. However, their roles in tumor angiogenesis and hence tumor growth and metastasis still remain uncertain. In this work, angiopoietin 1 expression was amplified in human cervical cancer HeLa cells by stable transfection or recombinant human adenovirus-mediated gene transfer. We show that increased angiopoietin 1 expression promoted in vivo growth of human cervical cancers in mice by promoting tumor angiogenesis and inhibiting tumor cell apoptosis. Furthermore, we also show for the first time that overexpression of angiopoietin 1 also leads to increased tumor vessel plasticity with a large number of vessels lacking periendothelial supporting cells. These results indicate that angiopoietin 1 promotes tumor angiogenesis and tumor vessel plasticity of human cervical cancer in mice.