Search

We present a detailed abundance analysis of 23 elements for a newly discovered carbon-enhanced metal-poor (CEMP) star, HE 0414−0343, from the Chemical Abundances of Stars in the Halo Project. Its spectroscopic stellar parameters are Teff = 4863 K, ξ = 2.20 km s−1, and [Fe/H] = −2.24. Radial velocity measurements covering seven years indicate HE 0414−0343 to be a binary. HE 0414−0343 has and is strongly enhanced in neutron-capture elements but its abundances cannot be reproduced by a solar-type s-process pattern alone. Traditionally, it could be classified as a “CEMP-r/s” star. Based on abundance comparisons with asymptotic giant branch (AGB) star nucleosynthesis models, we suggest a new physically motivated origin and classification scheme for CEMP-s stars and the still poorly understood CEMP-r/s. The new scheme describes a continuous transition between these two so-far distinctly treated subgroups: CEMP-sA, CEMP-sB, and CEMP-sC. Possible causes for a continuous transition include the number of thermal pulses the AGB companion underwent, the effect of different AGB star masses on their nucleosynthetic yields, and physics that is not well approximated in 1D stellar models such as proton ingestion episodes and rotation. Based on a set of detailed AGB models, we suggest the abundance signature of HE 0414−0343 to have arisen from a >1.3 M⊙ mass AGB star and a late-time mass transfer that transformed HE 0414−0343 into a CEMP-sC star. We also find that the [Y/Ba] ratio well parametrizes the classification and can thus be used to easily classify any future such stars. [ABSTRACT FROM AUTHOR]

Human malignant melanoma is a highly metastatic tumor with poor prognosis. The majority of metastatic melanomas are resistant to diverse chemotherapeutic agents. Consequently, the search for novel antimelanoma agents continues. In recent years, the interest in plants and their biologically active constituents as a source of novel potential drugs significantly increased. Inositol hexaphosphate (IP6) is a naturally occurring compound that has been shown to inhibit the growth of a wide variety of tumor cells in multiple experimental model systems. The aim of this study was to evaluate the antiproliferative and cytotoxic influence of IP6 on melanotic melanoma cells in vitro. The A2058 cells used as a model of human skin melanoma malignum were exposed to different concentrations of IP6 (0.1-5 mM) for a various period of time and their growth was determined by sulforhodamine B assay after 24, 48 and 72 h. The cytotoxicity of IP6 was measured at 24 and 72 h by XTT assay. IP6 has been found to cause dose-dependent growth suppression of A2058 melanoma cells. At low concentrations (0.1 and 0.5 mM) it did not exert any influence on the cell proliferation as compared to control cultures. Higher concentrations of IP6 (from 1 to 5 mM) had a statistically significant, suppressive effect on cell proliferation after 24 h incubation. When the experimental time period was increased up to 72 h, statistically significant inhibition of cell proliferation was monitored at all IP6 concentrations used. Data obtained from XTT assay indicated that IP6 had dose- and time-dependent cytotoxic effect on melanoma cells. The results demonstrate the antiproliferative and cytotoxic properties of IP6 in a wide range of concentrations on human A2058 melanoma cells. Hence, it can be suggested that IP6 could have a promising therapeutic significance in treating cancer.

Colon cancer has been remaining the second leading cause of cancer mortality in Poland in the last years. Epidemiological, preclinical and clinical studies reveal that dietary phytochemicals may exert chemopreventive and therapeutic effect against colorectal cancer. There is a growing interest in identifying new biologically active agents from dietary sources in this respect. Pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene) is a naturally occurring stilbene, that has been found to have antioxidative, anti-inflammatory and antipro- liferative properties. Compared to other stilbenes, pterostilbene has greater bioavailability, and so, a greater potential for clinical applications. Recent studies showed that pterostilbene exhibits the hallmark characteristics of an anticancer agent. The aim of this study was to analyze antiproliferative and cytotoxic effects of pterostilbene on human colon cancer Caco-2 cells. They were cultured using standard techniques and exposed to increasing doses of pterostilbene (5-100 μM) for 48 and 72 h. Cell proliferation was determined by sulforhodamine B assay. The growth of treated cells was expressed as a percentage of that of untreated control cells. Pterostilbene decreased proliferation rate of Caco-2 cells in a dose- and time-dependent manner. Its concentrations = 25 μM did not affect cell growth after 48 h treatment period. Significant growth inhibition was observed in cultures incubated with higher concentrations of pterostilbene (40-100 μM). Pterostilbene at all concentrations used (5-100 μM) caused significant inhibition of cell proliferation when the experimental time period was elongated to 72 h. The maximum growth reduction was observed at 100 mM pterostilbene. The cytotoxicity of pterostilbene was evaluated in 48 h cultures based on lactate dehydrogenase (LDH) leakage into the culture medium and showed dose-related pattern. The findings of this study showed significant dose-dependent antiproliferative and cytotoxic effects of pterostilbene against human colon cancer cells in vitro.

Transforming growth factors-beta (TGF-beta) are multifunctional cytokines involved in the regulation of cell development, differentiation, survival and apoptosis. They are also potent anticancer agents that inhibit uncontrolled proliferation of cells. Incorrect TGF-beta regulation has been implicated in the pathogenesis of many diseases including inflammation and cancer. In humans, the TGF-beta family consists of three members (TGF-beta1, 2, 3) that show high similarity and homology. TGF-betas exert biological activities on various cell types including neoplastic cells via their specific receptors. Inositol hexaphosphate (phytic acid, IP6), a phytochemical has been reported to possess various health benefits. The aim of this study was to examine the effect of IP6 on the expression of genes encoding TGF-beta1, TGF-beta2, TGF-beta3 isoforms and their receptors TbetaRI, TbetaRII, TbetaRIII in human colorectal cancer cell line Caco-2. The cells were treated with 0.5, 1 and 2.5 mM IP6 for 3, 6 and 12 h. The untreated Caco-2 cells were used as the control. Quantification of genes expression was performed by real time QRT-PCR technique with a SYBR Green I chemistry. The experimental data revealed that the TGF-beta1 mRNA was the predominant isoform in Caco-2 cells and that IP6 enhanced transcriptional activity of genes of all three TGF-beta isoforms and their receptors TbetaRI, TbetaRII TbetaRIII in these cells. At concentrations up to 1 mM, IP6 over-expressed the genes in 6 h lasting cultures, and its higher dose (2.5 mM) caused successively increasing transcript level of TGF-beta isoforms and receptors with the duration of experiment up to 12 h. The findings of this study indicate that one of anti-cancer abilities of IP6 can be realized by enhancing the gene expression of TGF-beta isoforms and their receptors at the transcriptional level.

Intestinal epithelial cells play an important role in the mucosal immune and inflammatory reactions via the expression and secretion of proinflammatory cytokines such as interleukin-6 (IL-6) and interleukin-8 (IL-8). The expression of both interleukins is regulated by nuclear factor KB (NF-kappaB). Phytic acid (IP6) is an essential component of high fiber diet. It is physiologically present in the human large gut at concentrations reaching 4 mM. It exhibits pleiotropic health beneficial effects including anti-oxidant and anti-tumor activities. Recent studies showed that IP6 can modulate immune functions of intestinal epithelium through regulation of proinflammatory cytokines secretion. The aim of this study was to analyze the effect of IP6 on the expression of IL-6 and IL-8 as well as p50 and p65 subunits of NF-kappaB and its inhibitor IkappaBalpha in Caco-2 cells stimulated with IL-1beta. A kinetic study of mRNAs expression in cells was performed after their treatment with 1 and 2.5 mM IP6 for 3, 6 and 12 h. Quantification of the genes expression was carried out using real time QRT-PCR technique. IP6 at all used concentrations had no influence on transcription of p65 gene and modulated expression of p50 and IkappaBalpha genes in Caco-2 cells. Treatment of cells with IP6 resulted in a marked decrease in both IL-6 (at 3 and 6 h) and IL-8 expression (3 h). The results of these studies suggest that IP6 may exert immunoregulatory effects on intestinal epithelium by influencing transcriptional activity of genes encoding p50 subunit of NF-kappaB, its inhibitor IkappaBalpha and proinflammatory cytokines IL-6 and IL-8.

Soluble adhesion molecules such as soluble intercellular adhesion molecules-1 (sICAM-1) and soluble E-cadherin (sE-cadherin) play important role in tumor invasion and the development of metastasis. It was observed that their concentrations in body fluids of patients with colon cancer were elevated. Celecoxib, a selective inhibitor of cyclooxygenase-2 (COX-2) besides its analgesic, anti-inflammatory, and antipyretic activity is able to inhibit development of colon cancer and reduce risk of metastasis. The additional factors, e.g., dietary components in colon cancer, may influence therapeutic effect of drugs, such as cytokines. TNF-alpha (tumor necrosis factor - alpha) is a cytokine, which concentration significantly increases in serum of patients with inflammatory and cancer diseases. The latest studies demonstrate, that phytic acid (IP6), a myo-inositol derivative, abundantly present in high-fiber diets could substantially reduce colon cancer incidence. The aim of the present study was to evaluate the influence of celecoxib on sICAM-1 and sE-cadherin concentrations in transformed epithelial colon cell cultures simultaneously exposed to IP6 and TNF-alpha. Additionally, the adhesion of the exposed cells to collagen I was assessed. HT-29 and Caco-2 cells were cultured in the presence of 50 ng/mL celecoxib, 1.0 mM IP6, and 100 ng/mL TNF-alpha, and their combination: TNF-alpha plus IP6, TNF-alpha plus celecoxib, IP6 plus celecoxib, and TNF-alpha with celecoxib plus IP6, for 96 h. Nonexposed cell line cultures served as controls. Concentrations of sICAM-1 and sE-cadherin were measured in the culture medium by enzyme-linked immunosorbent assay (ELISA) using Quantikine - Human sICAM-1/CD54 Immunoassay and Quantikine-Human sE-Cadherin Immunoassay. All the results obtained were expressed as ng per mL. In the adhesion assay, the cells were incubated with IP6 (0.5, 1.0 and 2.0 mM), TNF-alpha (100 ng/mL), celecoxib (50 ng/mL) and their combination for 90 min. Fluorescence values 480 nm/530 nm reflected concentrations of DNA in cells attached to collagen I. The obtained results indicate that celecoxib (50 ng/mL), the selective COX-2 inhibitor, reduces significantly sICAM-1 and sE-cadherin concentrations in HT-29 and Caco-2 transformed human epithelial colorectal cell line cultures co-treated with IP6 (1.0 mM) and TNF-alpha (100 ng/mL). A decrease of cells adhesion property to collagen I was observed under the influence of 50 ng/mL celecoxib on cell cultures exposed to 1.0 or 2.0 mM IP6 and 1.0 or 2.0 mM IP6 plus 100 ng/mL TNF-alpha.

Inositol hexaphosphate (IP6) is a naturally occurring phytochemical, found in abundance in cereals, legumes and other high-fiber-content diets. IP6 has shown promising efficacy against a wide range of cancers. Its anti-cancer activity involves anti-proliferative, pro-apoptotic and anti-metastatic effects. Both matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), are implicated in tumor growth, metastasis, and angiogenesis. Phorbol-12-myristate 13-acetate (PMA) is a well-known inflammatory stimulator and tumor promoter that activates PKC and increases the invasiveness of various types of cancer cells by activating MMPs. The aim of the present study was to examine the influence of IP6 on the expression of selected MMPs, i.e., MMP-1, -2, -3, -9, 10, -13 and their TIMP-1 and -2 in unstimulated and PMA-stimulated colon cancer cell line Caco-2. Quantification of genes expression in Caco-2 cells treated with 100 ng/mL of PMA, 2.5 mM of IP6 and both for 6 and 12 h was carried out using real time QRT-PCR technique. Stimulation of cells with PMA resulted in an up-expression of MMP-2, MMP-3, MMP-9, MMP-10, MMP-13 and TIMP-1 mRNAs and decrease in MMP-1 gene expression. The quantity of TIMP-2 transcript was reduced by PMA. A significant decrease in MMP-2, MMP-3, MMP-10, MMP-13, and TIMP-1 expression in response to IP6 was observed. IP6 down-regulated MMP-9 transcription induced by PMA and decreased the level of both MMP-2 and MMP-3 mRNAs in PMA-stimulated cells. Caco-2 treated with both PMA and IP6 showed a significant decrease in MMP-1 expression in comparison to PMA-stimulated cells. The results of this study show that PMA can modulate MMP and TIMP genes transcription in colon cancer cells Caco-2. IP6 exerts an influence of basal mRNA expression of some MMPs and their tissue inhibitors and down-regulates MMP-1, MMP-2, MMP-3 and MMP-9 in cells treated with PMA. IP6 could be an effective anti-metastatic agent that suppresses expression of MMP genes at transcription level.

Phytic acid (IP6) is an essential component of high fiber diet physiologically present in human large gut. It has been recognized to possess various significant health benefits effects including chemopreventive and have antineoplastic activity against various types of cancer. Moreover, its role in immune response through modulation of the secretion of proinflammatory cytokines and chemokines has been postulated. One of the signal transduction pathways involved in a variety of inflammatory responses is p38 mitogen-activated protein kinase (MAPK) pathway. The aim of this study was to examine effect of IP6 on human p38alpha MAP kinase activity and the expression of gene encoding p38 MAP kinase in unstimulated and IL-1beta-stimulated Caco-2 cells. Furthermore, the role of signaling pathways involving p38 MAP kinase in IP6-induced down-regulation of IL-8 secretion by unstimulated and IL-1beta-stimulated cells in the presence of p38 MAP kinase activator (anisomycin) and inhibitor (SB 203580) was evaluated. IP6 inhibited activity of recombinant p38 MAPK activity in dose-dependent manner. Treatment of cells with IP6 for 3 h resulted in decreased p38 MAP kinase expression in both unstimulated and stimulated with IL-1beta cells. The similar level of p38alpha mRNA was found in untreated and treated with IP6 cells after 6 and 12 h. Incubation of Caco-2 cells with anisomycin resulted in upregulation of IL-8 secretion and their pretreatment with anisomycin prior to IP6 addition showed down-regulation of IL-8 secretion compared to cells treated with anisomycin alone. The findings of this study show that p38 MAPK could be one of the molecular targets for IP6 in the intestinal epithelial cells and that IP6 inhibitory effect on IL-8 secretion by Caco-2 cells could be mediated by its inhibition of p38 activity.