Anti-metastatic and differential effects on protein expression of epigallocatechin-3-gallate in HCCLM6 hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third highest cause of cancer-related mortality in humans. Epigallocatechin-3-gallate (EGCG) has been shown to inhibit the metastatic activity of certain cancer cells. The aim of this study was to determine the effects and molecular mechanism(s) of action of EGCG in human HCC cells. A migration and invasion assay for the metastatic behavior of HCCLM6 cells was performed. The anti-metastatic effects of EGCG were investigated by RT-PCR and gelatin zymography. A total cellular protein profile was obtained using 2-dimensional gel electrophoresis (2-DE), followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) analyses of proteins with significant differences in expression following treatment with EGCG. The results revealed that EGCG induced apoptosis and inhibited the metastasis of HCCLM6 cells. The anti-metastatic effects of EGCG were associated with the inhibition of matrix metalloproteinase (MMP)-2 and MMP-9 activity. The expression levels of far upstream element (FUSE) binding protein 1 (FUBP1), heat shock protein beta 1 (HSPB1), heat shock 60 kDa protein 1 (chaperonin) (CH60) and nucleophosmin (NPM) proteins, which are associated with metastasis, were significantly altered in the EGCG-treated HCCLM6 cells. The data from the present study suggest that EGCG has potential as a therapeutic agent for the treatment of HCC.

Complex coacervation with whey protein isolate and gum arabic for the microencapsulation of omega-3 rich tuna oil.

Tuna oil rich in omega-3 fatty acids was microencapsulated in whey protein isolate (WPI)-gum arabic (GA) complex coacervates, and subsequently dried using spray and freeze drying to produce solid microcapsules. The oxidative stability, oil microencapsulation efficiency, surface oil and morphology of these solid microcapsules were determined. The complex coacervation process between WPI and GA was optimised in terms of pH, and WPI-to-GA ratio, using zeta potential, turbidity, and morphology of the microcapsules. The optimum pH and WPI-to-GA ratio for complex coacervation was found to be 3.75 and 3 : 1, respectively. The spray dried solid microcapsules had better stability against oxidation, higher oil microencapsulation efficiency and lower surface oil content compared to the freeze dried microcapsules. The surface of the spray dried microcapsules did not show microscopic pores while the surface of the freeze dried microcapsules was more porous. This study suggests that solid microcapsules of omega-3 rich oils can be produced using WPI-GA complex coacervates followed by spray drying and these microcapsules can be quite stable against oxidation. These microcapsules can have many potential applications in the functional food and nutraceuticals industry.

Co-encapsulation and characterisation of omega-3 fatty acids and probiotic bacteria in whey protein isolate-gum Arabic complex coacervates

Omega-3 fatty acids and probiotic bacteria were co-encapsulated in a single whey protein isolate (WPI)-gum Arabic (GA) complex coacervate microcapsule. Tuna oil (O) and Lactobacillus casei 431 (P) were used as models of omega-3 and probiotic bacteria, respectively. The co-microcapsules (WPI-P-O-GA) and L.casei containing microcapsules (WPI-P-GA) were converted into powder by using spray and freeze drying. The viability of L.casei was significantly higher in WPI-P-O-GA co-microcapsules than in WPI-P-GA. The oxidative stability of tuna oil was significantly higher in spray dried co-capsules than in freeze dried ones.

NDRG2 promotes myoblast proliferation and caspase 3/7 activities during differentiation, and attenuates hydrogen peroxide - but not palmitate-induced toxicity

The function of the stress-responsive N-myc downstream-regulated gene 2 (NDRG2) in the control of myoblast growth, and the amino acids contributing to its function, are not well characterized. Here, we investigated the effect of increased NDRG2 levels on the proliferation, differentiation and apoptosis in skeletal muscle cells under basal and stress conditions. NDRG2 overexpression increased C2C12 myoblast proliferation and the expression of positive cell cycle regulators, cdk2, cyclin B and cyclin D, and phosphorylation of Rb, while the serine/threonine-deficient NDRG2, 3A-NDRG2, had less effect. The onset of differentiation was enhanced by NDRG2 as determined through the myogenic regulatory factor expression profiles and myocyte fusion index. However, the overall level of differentiation in myotubes was not different. While NDRG2 up-regulated caspase 3/7 activities during differentiation, no increase in apoptosis was measured by TUNEL assay or through cleavage of caspase 3 and PARP proteins. During H2O2 treatment to induce oxidative stress, NDRG2 helped protect against the loss of proliferation and ER stress as measured by GRP78 expression with 3A-NDRG2 displaying less protection. NDRG2 also attenuated apoptosis by reducing cleavage of PARP and caspase 3 and expression of pro-apoptotic Bax while enhancing the pro-survival Bcl-2 and Bcl-xL levels. In contrast, Mcl-1 was not altered, and NDRG2 did not protect against palmitate-induced lipotoxicity. Our findings show that NDRG2 overexpression increases myoblast proliferation and caspase 3/7 activities without increasing overall differentiation. Furthermore, NDRG2 attenuates H2O2-induced oxidative stress and specific serine and threonine amino acid residues appear to contribute to its function in muscle cells.

Apicoplast-localized lysophosphatidic acid precursor assembly is required for bulk phospholipid synthesis in toxoplasma gondii and relies on an algal/plant-like glycerol 3-phosphate acyltransferase

Most apicomplexan parasites possess a non-photosynthetic plastid (the apicoplast), which harbors enzymes for a number of metabolic pathways, including a prokaryotic type II fatty acid synthesis (FASII) pathway. In Toxoplasma gondii, the causative agent of toxoplasmosis, the FASII pathway is essential for parasite growth and infectivity. However, little is known about the fate of fatty acids synthesized by FASII. In this study, we have investigated the function of a plant-like glycerol 3-phosphate acyltransferase (TgATS1) that localizes to the T. gondii apicoplast. Knock-down of TgATS1 resulted in significantly reduced incorporation of FASII-synthesized fatty acids into phosphatidic acid and downstream phospholipids and a severe defect in intracellular parasite replication and survival. Lipidomic analysis demonstrated that lipid precursors are made in, and exported from, the apicoplast for de novo biosynthesis of bulk phospholipids. This study reveals that the apicoplast-located FASII and ATS1, which are primarily used to generate plastid galactolipids in plants and algae, instead generate bulk phospholipids for membrane biogenesis in T. gondii.