Anticancer Properties of PPARα-Effects on Cellular Metabolism and Inflammation

Peroxisome proliferator-activated receptors (PPARs) have lately attracted much attention as therapeutic targets. Previously, PPAR ligands were associated with the treatment of diabetes, hyperlipidemia and cardiovascular diseases, as they modulate the expression of genes regulating glucose and lipid metabolism. Recently, PPAR ligands have been also considered as potential anticancer agents, with relatively low systemic toxicity. The emerging evidence for antiproliferative, proapoptotic, antiinflammatory and potential antimetastatic properties of PPARα ligands prompted us to discuss possible roles of PPARα in tumor suppression. PPARα activation can target cancer cells energy balance by blocking fatty acid synthesis and by promoting fatty acid β-oxidation. In the state of limited nutrient availability, frequently presents in the tumor microenvironment, PPARα cooperates with AMP-dependent protein kinase in: (i) repressing oncogenic Akt activity, (ii) inhibiting cell proliferation, and (iii) forcing glycolysis-dependent cancer cells into “metabolic catastrophe.” Other potential anticancer effects of PPARα include suppression of inflammation, and upregulation of uncoupling proteins (UCPs), which attenuates mitochondrial reactive oxygen species production and cell proliferation. In conclusion, there are strong premises that the low-toxic and well-tolerated PPAR ligands should be considered as new therapeutic agents to fight disseminating cancer, which represents the major challenge for modern medicine and basic research

Vzájomné pôsobenie citrinínu a resveratrolu a ich vplyv na rast Caco-2 buniek

The aim of this study was to use Caco-2 cells as an in vitro model of human intestina barrier. This model was employed to investigate interaction of citrinin and resveratrol and to determine the doses that affect cell number. Citrinin (CTN) is a toxic secondary metabolite produced by fungi of the genera Penicillium, Aspergillus and Monascus. It is contaminant of cereals, grains, food and feed products. Previous studies have shown that CTN has teratogenic, nephrotoxic, hepatotoxic and embryotoxic effects. Resveratrol (RES) is polyphenol belongs to the group of stilbenes. At lower doses it has positive effects on human health and higher doses may induce apoptosis. The results of study indicate a significant (P < 0.05) decrease in cell number in all conditions: A (RES 20 μM), B (CTN 100 μg*ml-1), C (CTN 250 μg*ml-1), D (CTN 100 μg*ml-1 + RES 20 μM), E (CTN 250 μg*ml-1 + RES 20 μM) in comparison with the control group of non-treated cells (NT) and control group with ethanol (Ce). A significant (P <0.05) decrease in the cells number was observed between groups A - E, B - C and D - E. Citrinin effect seems to be dose-dependent.Cieľom práce bolo použitie Caco-2 buniek ako in vitro model črevnej bariéry na zistenie vzájomného pôsobenia citrinínu a resveratrolu a stanovenie dávok, ktoré majú vplyv na počet buniek. Citrinín (CTN) je toxický sekundárny metabolit, ktorý produkujú mikroskopické huby patriace do rodov Aspergillus, Penicillium a Monascus. Kontaminuje cereálie, obilniny, potraviny a krmivá. Predchádzajúce štúdie ukázali, že CTN má teratogénne, nefrotoxické, hepatotoxické a embryotoxické účinky. Resveratrol (RES) je polyfenol, ktorý patrí do skupiny stilbénov. Pri nižších dávkach má pozitívne účinky na ľudské zdravie a pri vyšších spôsobuje apoptózu buniek. Výsledky štúdie poukazujú na signifikantný (P < 0.05) pokles počtu buniek vo všetkých experimentálnych skupinách A (RES 20 μM), B (CTN 100 μg*ml-1), C (CTN 250 μg*ml-1), D (CTN 100 μg*ml-1 + RES 20 μM), E (CTN 250 μg*ml-1 + RES 20 μM) v porovnaní s kontrolnou skupinou s neošetrenými bunkami (NT) a kontrolnou skupinou s prídavkom etanolu (Ce). Významný (P < 0.05) pokles buniek sa zaznamenal medzi skupinami A - E, B - C a D - E. Pôsobenie citrinínu je dávkovo závislé

The in vitro digestates from Brussels sprouts processed with various hydrothermal treatments affect the intestinal epithelial cell differentiation, mitochondrial polarization and glutathione level

Brussels sprouts provide bioactive compounds with widely acknowledged health-promoting effects observed in various levels: single cells, organs and tissues, or the whole organism. However, the choice of the appropriate hydrothermal processing is critical to sustain the nutritional values and cytoprotective activities, as Brussels sprouts are rarely eaten raw. The aim of this study was to evaluate the impact of various culinary methods (boiling, steaming, and sous-vide in comparison to raw plant material) applied to Brussels sprouts on the chosen functions of liver and intestinal cell lines (HepG2 and Caco-2, respectively): the markers of enterocyte differentiation (alkaline phosphatase and sucrase-isomaltase activities and protein level), glutathione store management (total GSH concentration and Glu, Gly, Cys and Met amino acids analysis) and mitochondrial polarization (JC-1 staining analysis). The in vitro digestates from raw Brussels sprouts had a stronger positive effect on the enterocyte marker enzymes in the Caco-2 cultures as compared to the digestates from the hydrothermally processed vegetables (boiled, steamed, and sous-vide). The sous-vide method diminished the intracellular glutathione stores. Hydrothermal processing, particularly steaming and sous-vide had a negative impact on the mitochondrial abundance and polarization as compared to raw vegetables. Our results suggest that shorter processing is more beneficial to retain glutathione and mitochondrial polarization than longer hydrothermal treatment

RIPK4 downregulation impairs Wnt3A-stimulated invasiveness via Wnt/β\beta-catenin signaling in melanoma cells and tumor growth in vivo

Purpose The role of Wnt signaling in oncogenesis and drug resistance is well known. Receptor-interacting protein kinase (RIPK4) contributing to the increased activity of many signaling pathways, including Wnt/$\beta$-catenin, may be an important target for designing new drugs for metastatic melanoma, but its role in melanoma is not fully understood. Methods We tested the effect of genetic manipulation of RIPK4 (CRISPR/Cas9) on xenograft growth. In addition, immunohistochemistry was used to detect active $\beta$-catenin, Ki67 and necrosis in xenografts. Wnt signaling pathway activity was examined using Western blot and Top-Flash. The effect of RIPK4 knockout on melanoma cells in vitro stimulated Wnt3A on wound overgrowth, migration and invasion ability was then evaluated. Results Our study showed that CRISPR/Cas9-mediated RIPK4 knockout (KO) significantly reduced tumor growth in a mouse model of melanoma, particularly of WM266.4 cells. RIPK4 KO tumors exhibited lower percentages of $Ki67^{+}$ cells as well as reduced necrotic area and decreased levels of active $\beta$-catenin. In addition, we observed that RIPK4 knockout impaired Wnt3A-induced activation of LRP6 and $\beta$-catenin, as manifested by a decrease in the transcriptional activity of $\beta$-catenin in Top-Flash in both tested melanoma cell lines, A375 and WM266.4. Prolonged incubation (48 h) with Wnt3A showed reduced level of MMP9, C-myc, and increased SOX10, proteins whose transcription is also dependent on $\beta$-catenin activity. Moreover, RIPK4 knockout led to the inhibition of scratch overgrowth, migration and invasion of these cells compared to their controls. Conclusion RIPK4 knockdown inhibits melanoma tumor growth and Wnt3A stimulated migration and invasion indicating that RIPK4 might be a potential target for melanoma therapy

The PPAR&alpha; Regulation of the Gut Physiology in Regard to Interaction with Microbiota, Intestinal Immunity, Metabolism, and Permeability

Peroxisome proliferator-activated receptor alpha (PPAR&alpha;) is expressed throughout the mammalian gut: in epithelial cells, in the villi of enterocytes and in Paneth cells of intestinal crypts, as well as in some immune cells (e.g., lamina propria macrophages, dendritic cells) of the mucosa. This review examines the reciprocal interaction between PPAR&alpha; activation and intestinal microbiota. We refer to the published data confirming that microbiota products can influence PPAR&alpha; signaling and, on the other hand, PPAR&alpha; activation is able to affect microbiota profile, viability, and diversity. PPAR&alpha; impact on the broad spectrum of events connected to metabolism, signaling (e.g., NO production), immunological tolerance to dietary antigens, immunity and permeability of the gut are also discussed. We believe that the phenomena described here play a prominent role in gut homeostasis. Therefore, in conclusion we propose future directions for research, including the application of synthetic activators and natural endogenous ligands of PPAR&alpha; (i.e., endocannabinoids) as therapeutics for intestinal pathologies and systemic diseases assumed to be related to gut dysbiosis

Melanin synthesis in microorganisms - biotechnological and medical aspects

Melanins form a diverse group of pigments synthesized in living organisms in the course of hydroxylation and polymerization of organic compounds. Melanin production is observed in all large taxa from both Pro- and Eukaryota. The basic functions of melanins are still a matter of controversy and speculation, even though their adaptative importance has been proved. Melanogenesis has probably evolved paralelly in various groups of free living organisms to provide protection from environmental stress conditions, but in pathogenic microorganisms it correlates with an increased virulence. The genes responsible for melanization are collected in some cases within operons which find a versatile application in genetic engineering. This review sumarizes current views on melanogenesis in Pro- and Eukaryotic microorganisms in terms of their biotechnological and biomedical importance