We investigated the biomechanical relationship between intraluminal pressure within small mesenteric resistance arteries, oxidant activation of PKG, Ca2+ sparks, and BK channel vasoregulation. Mesenteric resistance arteries from wild type (WT) and genetically modified mice with PKG resistance to oxidative activation were studied using wire and pressure myography. Ca2+ sparks and Ca2+ transients within vascular smooth muscle cells of intact arteries were characterized using high-speed confocal microscopy of intact arteries. Arteries were studied under conditions of varying intraluminal pressure and oxidation. Intraluminal pressure specifically, rather than the generic stretch of the artery, was necessary to activate the oxidative pathway. We demonstrated a graded step activation profile for the generation of Ca2+ sparks and also a functional "ceiling" for this pressure --sensitive oxidative pathway. During steady state pressure - induced constriction, any additional Ca2+ sensitive-K+ channel functional availability was independent of oxidant activated PKG. There was an increase in the amplitude, but not the Area under the Curve (AUC) of the caffeine-induced Ca2+ transient in pressurized arteries from mice with oxidant-resistant PKG compared with wild type. Overall, we surmise that intraluminal pressure within resistance arteries controls Ca2+ spark vasoregulation through a tightly controlled pathway with a graded onset switch. The pathway, underpinned by oxidant activation of PKG, cannot be further boosted by additional pressure or oxidation once active. We propose that these restrictive characteristics of pressure-induced Ca2+ spark vasoregulation confer stability for the artery in order to provide a constant flow independent of additional pressure fluctuations or exogenous oxidants.
6-Shogaol has been shown to possess many antitumor properties including inhibition of cancer cell growth, inhibition of cancer metastasis, induction of apoptosis in cancer cells and induction of cancer cell differentiation. Despite its prominent antitumor effects, the direct molecular target of 6-shogaol has remained elusive. To identify the direct targets of 6-shogaol, a comprehensive antitumor profile of 6-shogaol (NSC752389) was tested in the NCI-60 cell line in an in vitro screen. The results show that 6-shogaol is COMPARE negative suggesting that it functions via a mechanism of action distinct from existing classes of therapeutic agents. Further analysis using microarray gene profiling and Connectivity Map analysis showed that MCF-7 cells treated with 6-shogaol display gene expression signatures characteristic of peroxisome proliferator activated receptor γ (PPARγ) agonists, suggesting that 6-shogaol may activate the PPARγ signaling pathway for its antitumor effects. Indeed, treatment of MCF-7 and HT29 cells with 6-shogaol induced PPARγ transcriptional activity, suppressed NFκB activity, and induced apoptosis in breast and colon cancer cells in a PPARγ-dependent manner. Furthermore, 6-shogaol is capable of binding to PPARγ with a binding affinity comparable to 15-delta prostaglandin J2, a natural ligand for PPARγ. Together, our findings suggest that the antitumor effects of 6-shogaol are mediated through activation of PPARγ and imply that activation of PPARγ might be beneficial for breast and colon cancer treatment.
Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w) Triton X-100 and 20% (w/w) xylitol, at 56.2% of tie line length (TLL), (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases) and a crude load of 25% (w/w) at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase.
This study investigates the effect of ACE2 activation on leptin-induced changes in systolic blood pressure (SBP), proteinuria, endothelial activation and ACE2 expression during pregnancy in Sprague-Dawley rats. Pregnant rats were given subcutaneous injection of either saline, or leptin, or leptin plus xanthenone (ACE2 activator), or xanthenone (XTN) alone. SBP, serum ACE, ACE2, endothelin-1, E-selectin and ICAM-1 levels were estimated; also their gene expressions were determined in the kidney and aorta respectively. Compared to control, SBP was higher in the leptin-only treated group (P<0.001) and lower in rats treated with xanthenone alone (P<0.01). Proteinuria, markers of endothelial activation were significantly higher than controls in leptin-only treated rats (P<0.05). ACE2 activity and expression were lower in leptin-only treated rats when compared to controls (P<0.05). It seems, leptin administration during pregnancy significantly increases SBP, proteinuria, endothelial activation, but decreases ACE2 level and expression. These effects are prevented by concurrent administration of xanthenone.
Comparative proteomic profiling between 2 vancomycin-intermediate Staphylococcus aureus (VISA) strains, Mu50Ω-vraSm and Mu50Ω-vraSm-graRm, and vancomycin-susceptible S. aureus (VSSA) strain Mu50Ω revealed upregulated levels of catabolic ornithine carbamoyltransferase (ArcB) of the arginine catabolism pathway in VISA strains. Subsequent analyses showed that the VISA strains have higher levels of cellular ATP and ammonia, which are by-products of arginine catabolism, and displayed thicker cell walls. We postulate that elevated cytoplasmic ammonia and ATP molecules, resulting from activated arginine catabolism upon acquisition of vraS and graR mutations, are important requirements facilitating cell wall biosynthesis, thereby contributing to thickened cell wall and consequently reduced vancomycin susceptibility in VISA strains.
Dysregulation of E-cadherin and β-catenin function in cell-cell adhesion is common in nasopharyngeal carcinoma (NPC) and correlates with metastatic disease. In this study, we examined the role of EGF-activated phosphatidylinositol 3-kinase (PI3K)-Akt signaling in E-cadherin and β-catenin regulation. We found that reduced membranous E-cadherin and β-catenin expression was positively correlated with Akt phosphorylation in NPC tissues. EGF treatment disrupted cell-cell adhesion and resulted in mesenchymal morphological features in NPC cell lines (TW01, TW04, and TW06). Western blot analysis showed that the E-cadherin protein level was partially reduced in TW04 cells only and the β-catenin levels were not considerably affected upon EGF treatment. In contrast, quantitative real-time RT-PCR showed that the E-cadherin, but not β-catenin, mRNA levels were markedly reduced by EGF in all cell lines. Immunofluorescent staining revealed that E-cadherin and β-catenin appeared to be markedly reduced on the cell surface and more localized in the cytoplasm. Inhibition of PI3K by LY294002 did not abolish the EGF-induced downregulation of E-cadherin protein or mRNA in TW04 cells but moderately increased the β-catenin protein level in TW01 cells and mRNA level in TW06 cells. However, LY294002 substantially restored or increased cell surface E-cadherin and β-catenin in all EGF-treated cell lines, in concordance with the inhibition of cell morphological changes. Moreover, LY294002 significantly blocked EGF-driven cell invasion, correlating with the elevation of membranous E-cadherin and β-catenin levels. In conclusion, EGF-induced epithelial-to-mesenchymal transition may not be only dependent on downregulation of E-cadherin protein/mRNA but also on mislocalization of E-cadherin and β-catenin. The mechanisms involved may be related, at least in part, to the PI3K-Akt pathway.
Alpha-tomatine (α-tomatine) is the major saponin in tomato (Lycopersicon esculentum). This study investigates the chemopreventive potential of α-tomatine on androgen-independent human prostatic adenocarcinoma PC-3 cells.
A series of hexahydro-1,6-naphthyridines were synthesized in good yields by the reaction of 3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones with cyanoacetamide in the presence of sodium ethoxide under simple mixing at ambient temperature for 6-10 minutes and were assayed for their acetylcholinesterase (AChE) inhibitory activity using colorimetric Ellman's method. Compound 4e with methoxy substituent at ortho-position of the phenyl rings displayed the maximum inhibitory activity with IC50 value of 2.12 μM. Molecular modeling simulation of 4e was performed using three-dimensional structure of Torpedo californica AChE (TcAChE) enzyme to disclose binding interaction and orientation of this molecule into the active site gorge of the receptor.
Plants that help in slowing down the digestion of triacylglycerols (TAGs) in the pancreas and small intestine of humans play an important role in the reduction of obesity. On the other hand, there may be plants or plant parts that stimulate intestinal lipolytic activity, thus contributing to greater TAG assimilation. The aim of this study was to evaluate the aqueous methanolic extracts of ninety eight (98) medicinal, herbal and aquatic plant materials from Malaysia for their effect on porcine pancreatic lipase (PPL) activity and to identify the structure of an anti-lipase compound from one of the sources. The degree of inhibition was also quantified as relative to orlistat activity against PPL (orlistat equivalents). Results revealed that while 19.4% of the extracts were found to have anti-lipase activity ≥80%, 12% were actually found to promote PPL activity. Twenty two percent (22.4%) exhibited moderate inhibition (41%-80%) and 2% were neutral toward PPL activity. The ripe fruit of Averrhoa carambola and the leaves of Archidendron jiringa (Jack) I.C Nielsen L. (jering), Cynometra cauliflora (nam-nam) and Aleurites moluccana (L.) Willd (candle nut/buah keras) had the highest (100%) anti-lipase activity and are equivalent to 0.11 µg orlistat/mL. Plants that stimulated lipase activity included Pimpinella anisum L. (aniseed/jintan manis), activating the enzyme by 186.5%. Kaempferol 3-O-rhamnoside was isolated from the ethyl acetate fraction of C. cauliflora leaves and found to be an active lipase inhibitor. The structure was elucidated using 1H-NMR, 13C-NMR and 2D-NMR analyses.
Despite being widely used traditionally as a general tonic, especially in South East Asia, scientific research on Cassia timoriensis, remains scarce. In this study, the aim was to evaluate the in vitro activities for acetylcholinesterase (AChE) inhibitory potential, radical scavenging ability, and the anti-inflammatory properties of different extracts of C. timoriensis flowers using Ellman's assay, a DPPH assay, and an albumin denaturation assay, respectively. With the exception of the acetylcholinesterase activity, to the best of our knowledge, these activities were reported for the first time for C. timoriensis flowers. The phytochemical analysis confirmed the existence of tannins, flavonoids, saponins, terpenoids, and steroids in the C. timoriensis flower extracts. The ethyl acetate extract possessed the highest phenolic and flavonoid contents (527.43 ± 5.83 mg GAE/g DW and 851.83 ± 10.08 mg QE/g DW, respectively) as compared to the other extracts. In addition, the ethyl acetate and methanol extracts exhibited the highest antioxidant (IC50 20.12 ± 0.12 and 34.48 ± 0.07 µg/mL, respectively), anti-inflammatory (92.50 ± 1.38 and 92.22 ± 1.09, respectively), and anti-AChE (IC50 6.91 ± 0.38 and 6.40 ± 0.27 µg/mL, respectively) activities. These results suggest that ethyl acetate and methanol extracts may contain bioactive compounds that can control neurodegenerative disorders, including Alzheimer's disease, through high antioxidant, anti-inflammatory, and anti-AChE activities.
The methanol extracts of three Macaranga species (M. denticulata, M. pruinosa, and M. gigantea) were screened to evaluate their total phenolic contents and activities as cholinesterase inhibitors, nitric oxide (NO) production inhibitors, tyrosinase inhibitors, and antioxidants. The bark of M. denticulata showed the highest total phenolic content (2682 mg gallic acid equivalent (GAE)/100 g) and free radical scavenging activity (IC50 = 0.063 mg/mL). All of the samples inhibited linoleic acid peroxidation by greater than 80%, with the leaves of M. gigantea exhibiting the highest inhibition of 92.21%. Most of the samples exhibited significant antioxidant potential. The bark of M. denticulata and the leaves of both M. pruinosa and M. gigantea exhibited greater than 50% tyrosinase inhibition, with the bark of M. denticulata having the highest percentage of inhibition (68.7%). The bark and leaves of M. denticulata exhibited greater than 50% inhibition (73.82% and 54.50%, resp.) of the acetylcholinesterase enzyme (AChE), while none of the samples showed any significant inhibition of butyrylcholinesterase (BChE). Only the bark of M. denticulata and M. gigantea displayed greater than 50% inhibition of nitric oxide production in cells (81.79% and 56.51%, resp.). These bioactivities indicate that some Macaranga spp. have therapeutic potential in medicinal research.
This study aims to investigate the mechanisms associated with the antiproliferation effect of guanosine on human colon carcinoma HCT 116 cells. In this study, guanosine induced more drastic cell cycle arrest effect than cell death effect on HCT 116 cells. The cell cycle arrest effect of guanosine on HCT 116 cells appeared to be associated with the increased activation of mitogen-activated protein kinases (MAPK) such as ERK1/2, p38 and JNK. The decrease of AMP-activated protein kinase (AMPK) activation and cyclin D1 expression was also involved. Thus, the antiproliferation of colon cancer cells of guanosine could be mediated by the disruption of MAPK and AMPK pathways.
Xanthorrhizol is a natural sesquiterpenoid compound isolated from the rhizome of Curcuma xanthorrhizza Roxb (Zingerberaceae). Recent studies of xanthorrhizol in cell cultures strongly support the role of xanthorrhizol as an antiproliferative agent. In our study, we tested the antiproliferative effect of xanthorrhizol using different breast cancer cell lines. The invasive breast cancer cell line, MDA-MB-231, was then selected for further investigations. Treatment with xanthorrhizol caused 50% growth inhibition on MDA-MB-231 cells at 8.67 +/- 0.79 microg/ml as determined by sulforhodamine B (SRB) assay. Hoechst 33258 nuclear staining assay showed the rate of apoptosis of MDA-MB-231 cells to increase in response to xanthorrhizol treatment. Immunofluorescence staining using antibody MitoCapture and fluorescein isothiocyanate (FITC)-labeled cytochrome c revealed the possibility of altered mitochondrial transmembrane potential and the release of cytochrome c respectively. This was further confirmed by Western-blotting, where cytochrome c was showed to migrate from mitochondrial fraction to the cytosol fraction of treated MDA-MB-231 cells. Caspase activity assay showed the involvement of caspase-3 and caspase-9, but not caspase-6 or caspase-8 in MDA-MB-231 apoptotic cell death. Subsequently, cleavage of PARP-1 protein is suggested. These data suggest treatment with xanthorrhizol modulates MDA-MB-231 cell apoptosis through the mitochondria-mediated pathway subsequent to the disruption of mitochondrial transmembrane potential, release of cytochrome c, activation of caspase-3 and caspase-9, and the modulation of PARP-1 protein.
para-Phenylenediamine (p-PD) is a suspected carcinogen, but it has been widely used as a component in permanent hair dyes. In this study, the mechanism of p-PD-induced cell death in normal Chang liver cells was investigated. The results demonstrated that p-PD decreased cell viability in a dose-dependent manner. Cell death via apoptosis was confirmed by enhanced DNA damage and increased cell number in the sub-G1 phase of the cell cycle, using Hoechst 33258 dye staining and flow cytometry analysis. Apoptosis via reactive oxygen species generation was detected by the dichlorofluorescin diacetate staining method. Mitogen-activated protein kinase (MAPK) activation was assessed by western blot analysis and revealed that p-PD activated not only stress-activated protein kinase (SAPK)/c-Jun N-terminal kinases (JNK) and p38 MAPK but also extracellular signal-regulated kinase (ERK). Cytotoxicity and apoptosis induced by p-PD were markedly enhanced by ERK activation and selectively inhibited by ERK inhibitor PD98059, thus indicating a negative role of ERK. In contrast, inhibition of p38 MAPK activity with the p38-specific inhibitor SB203580 moderately inhibited cytotoxicity and apoptosis induction by p-PD. Similarly, SP600125, an inhibitor of SAPK/JNK, moderately inhibited cytotoxicity and apoptosis induced by p-PD, thus implying that p38 MAPK and SAPK/JNK had a partial role in p-PD-induced apoptosis. Western blot analysis revealed that p-PD significantly increased phosphorylation of p38 and SAPK/JNK and decreased phosphorylation of ERK. In conclusion, the results demonstrated that SAPK/JNK and p38 cooperatively participate in apoptosis induced by p-PD and that a decreased ERK signal contributes to growth inhibition or apoptosis.
The development of metal-based agents has had a tremendous role in the present progress in cancer chemotherapy. One well-known example of metal-based agents is Schiff based metal complexes, which hold great promise for cancer therapy. Based on the potential of Schiff based complexes for the induction of apoptosis, this study aimed to examine the cytotoxic and apoptotic activity of a CdCl2(C14H21N3O2) complex on HT-29 cells. The complex exerted a potent suppressive effect on HT-29 cells with an IC50 value of 2.57 ± 0.39 after 72 h of treatment. The collapse of the mitochondrial membrane potential and the elevated release of cytochrome c from the mitochondria to the cytosol indicate the involvement of the intrinsic pathway in the induction of apoptosis. The role of the mitochondria-dependent apoptotic pathway was further proved by the significant activation of the initiator caspase-9 and the executioner caspases-3 and -7. In addition, the activation of caspase-8, which is associated with the suppression of NF-κB translocation to the nucleus, also revealed the involvement of the extrinsic pathway in the induced apoptosis. The results suggest that the CdCl2(C14H21N3O2) complex is able to induce the apoptosis of colon cancer cells and is a potential candidate for future cancer studies.
Chrysin is a natural flavonoid currently under investigation due to its important biological anti-cancer properties. In most of the cancer cells tested, chrysin has shown to inhibit proliferation and induce apoptosis, and is more potent than other tested flavonoids in leukemia cells, where chrysin is likely to act via activation of caspases and inactivation of Akt signaling in the cells. Moreover, structure-activity relationships have revealed that the chemical structure of chrysin meets the key structural requirements of flavonoids for potent cytotoxicity in leukemia cells. It is possible that combination therapy or modified chrysin could be more potent than single-agent use or administration of unmodified chrysin. This study may help to develop ways of improving the effectiveness of chrysin in the treatment of leukemia and other human cancers in vitro.
The aim of this study was to investigate the cytotoxic and apoptotic effects of Nephelium ramboutan-ake (pulasan) rind in selected human cancer cell lines. The crude ethanol extract and fractions (ethyl acetate and aqueous) of N. ramboutan-ake inhibited the growth of HT-29, HCT-116, MDA-MB-231, Ca Ski cells according to MTT assays. The N. ramboutan-ake aqueous fraction (NRAF) was found to exert the greatest cytotoxic effect against HT-29 in a dose-dependent manner. Evidence of apoptotic cell death was revealed by features such as chromatin condensation, nuclear fragmentation and apoptotic body formation. The result from a TUNEL assay strongly suggested that NRAF brings about DNA fragmentation in HT-29 cells. Phosphatidylserine (PS) externalization on the outer leaflet of plasma membranes was detected with annexin V-FITC/PI binding, confirming the early stage of apoptosis. The mitochondrial permeability transition is an important step in the induction of cellular apoptosis, and the results clearly suggested that NRAF led to collapse of mitochondrial transmembrane potential in HT-29 cells. This attenuation of mitochondrial membrane potential (Δψm) was accompanied by increased production of ROS and depletion of GSH, an increase of Bax protein expression, and induced-activation of caspase-3/7 and caspase-9. These combined results suggest that NRAF induces mitochondrial-mediated apoptosis.
Arctium lappa L. is a perennial herb traditionally consumed to improve well-being. It has been widely reported for its antioxidant properties; however, very little is known for its exact mechanisms underlying the anticancer activity. This study aimed to investigate the mechanisms of anticancer action for different A. lappa root extracts. Arctium lappa root was extracted with ethanol, hexane and ethyl acetate, then examined for in vitro anticancer activity against cancerous HeLa, MCF-7, Jurkat cell lines and non-cancerous 3T3 cell lines. Induction of apoptosis was determined by cellular morphological changes, mitochondrial membrane potential (ΔΨm), caspase-3/7 activity and DNA fragmentation. The active compounds present in the most potent root extracts were identified by LC-ESI-MS. Among all the extracts, ethyl acetate root extract has the highest potency with IC50 of 102.2 ± 42.4 μg/ml, followed by ethanolic root extract in Jurkat T cells, at 24 h. None of the extracts were cytotoxic against 3T3 cells, suggesting that the extracts were selective against cancerous cells only. Both ethyl acetate and ethanolic root extracts exhibited significant morphological changes in Jurkat T cells, including the detachment from adjacent cells, appearance of apoptotic bodies and cells shrinkage. The extracts treated cells also displayed an increase in caspase-3/7 activity and alteration in mitochondrial membrane potential. Only ethyl acetate root extract at IC50 induced DNA fragmentation in Jurkat T cells. LC-ESI-MS analysis of the extract revealed the presence of 8 compounds, of which only 6 compounds with various biological activities reported. These findings suggest that the ethyl acetate extract of A. lappa had strong anticancer potential and induced intrinsic apoptosis via loss of ΔΨm and activation of caspase-3/7 This study can provide new insight to the discovery of new promising lead compound in chemopreventive and chemotherapeutic strategies.
The aim of the present study was to determine whether or not lipopolysaccharide from Actinobacillus actinomycetemcomitans could stimulate arginase activity in a murine macrophage cell line (RAW264.7 cells).
Oxalate toxicity is mediated through generation of reactive oxygen species (ROS) via a process that is partly dependent on mitochondrial dysfunction. Here, we investigated whether C-phycocyanin (CP) could protect against oxidative stress-mediated intracellular damage triggered by oxalate in MDCK cells. DCFDA, a fluorescence-based probe and hexanoyl-lysine adduct (HEL), an oxidative stress marker were used to investigate the effect of CP on oxalate-induced ROS production and membrane lipid peroxidation (LPO). The role of CP against oxalate-induced oxidative stress was studied by the evaluation of mitochondrial membrane potential by JC1 fluorescein staining, quantification of ATP synthesis and stress-induced MAP kinases (JNK/SAPK and ERK1/2). Our results revealed that oxalate-induced cells show markedly increased ROS levels and HEL protein expression that were significantly decreased following pre-treatment with CP. Further, JC1 staining showed that CP pre-treatment conferred significant protection from mitochondrial membrane permeability and increased ATP production in CP-treated cells than oxalate-alone-treated cells. In addition, CP treated cells significantly decreased the expression of phosphorylated JNK/SAPK and ERK1/2 as compared to oxalate-alone-treated cells. We concluded that CP could be used as a potential free radical-scavenging therapeutic strategy against oxidative stress-associated diseases including urolithiasis.