Hong-Gu Lee

trans-11 18:1 Vaccenic Acid (TVA) Has a Direct Anti-Carcinogenic Effect on MCF-7 Human Mammary Adenocarcinoma Cells

Trans vaccenic acid (TVA; trans-11 18:1) is a positional and geometric isomer of oleic acid and it is the predominant trans isomer found in ruminant fats. TVA can be converted into cis-9, trans-11 conjugated linoleic acid (c9, t11-CLA), a CLA isomer that has many beneficial effects, by stearoyl CoA desaturase 1 (SCD1) in the mammary gland. The health benefits associated with CLA are well documented, but it is unclear whether trans fatty acids (TFAs) from ruminant products have healthy effects. Therefore, the effects of TVA on the proliferation of MCF-7 human breast adenocarcinoma cells and MCF-10A human breast epithelial cells were investigated in the present study. Results showed that TVA inhibited the proliferation of MCF-7 cells but not MCF-10A cells by down-regulating the expression of Bcl-2 as well as procaspase-9. In addition, the suppressive effect of TVA was confirmed in SCD1-depleted MCF-7 cells. Our results suggested that TVA exerts a direct anti-carcinogenic effect on MCF-7 cells. These findings provided a better understanding of the research on the anti-carcinogenic effects of TVA and this may facilitate the manufacture of TVA/c9, t11-CLA fortified ruminant products.

Myoglobin: A promising exogenous reference marker using in proteomics analysis

In 2-dimensional gel electrophoresis (2-DE) analysis, quantification of protein expression difference is difficult because of the high variation of spot sizes among gels. Therefore, identification of a reference marker for data normalization is necessary. In this study, consistent spot size and high reproducibility of myoglobin in 2-DE gels were successfully achieved. The use of myoglobin not only improved quantification of protein expression differences in images from different samples of the same tissue, but also made the comparison of difference in protein expression among different tissues possible. Thus, myoglobin is promising as a reference marker for data normalization in proteomic analysis.

Identification of proteins involved in the pancreatic exocrine by exogenous ghrelin administration in Sprague-Dawley rats

The aims of study were to investigate the effects of intraperitoneal (i.p.) infusion of ghrelin on pancreatic α-amylase outputs and the responses of pancreatic proteins to ghrelin that may relate to the pancreatic exocrine. Six male Sprague-Dawley rats (300 g) were randomly divided into two groups, a control group (C, n = 3) and a treatment group (T, 10.0μg/kg BW, n = 3). Blood samples were collected from rat caudal vein once time after one hour injection. The concentrations of plasma ghrelin, cholecystokinin (CCK) and alfa-amylase activity were evaluated by enzyme immunoassay (EIA) kit. Two-dimensional gel electrophoresis (2-DE) analysis was conducted to separate the proteins in pancreas tissue. Results showed that the i.p. infusion of ghrelin at doses of 10.0 μg/kg body weight (BW) increased the plasma ghrelin concentrations (p = 0.07) and elevated the plasma CCK level significantly (p < 0.05). Although there was no statistically significant, the α-amylase activity tended to increase. The proteomics analysis indicated that some pancreatic proteins with various functions were up- or down- regulated compared with control group. In conclusion, ghrelin may have role in the pancreatic exocrine, but the signaling pathway was still not clear. Therefore, much more functional studies focus on these found proteins are needed in the near future.

Trans vaccenic acid (trans-11 18:1), a precursor of cis-9, trans-11-conjugated linoleic acid, exerts a direct anti-carcinogenic function in T47D breast carcinoma cells

The role of TVA in suppressing proliferation of various human cancer cell lines was investigated that TVA and c9, t11-CLA both suppressed cell proliferation. The suppressive effect of TVA was clearly observed in T47D breast carcinoma cells after stearoyl-CoA desaturase-1 (SCD) knockdown using small interfering RNA (siRNA), demonstrating TVA directly affects suppression of human breast carcinogenesis.

Comparative studies on derivatization methods of single or mixed fatty acids

This study aimed to evaluate the methylation performances of three reagents (3 N HCl-MeOH, 14% BF3-MeOH, and 24 N H2SO4-MeOH) on single or mixed fatty acids. Results showed that 24 N H2SO4-MeOH (93.00%) had the best cis-9, trans-11 CLA methylation performance compared with that of 3 N HCl-MeOH (7.96%) or 14% BF3-MeOH (65.49%). There were no obvious differences in the composition of major fatty acids in soybean oil or extruded full-fat linseed after methylation by these reagents. On the contrary, the individual fatty acids showed various responses to these three reagents in chicken breast meat and chicken drum stick. In milk, no obvious differences were observed except for cis-9, trans-11 CLA. These data demonstrate that the methylation performances of the three reagents varied with the kinds of sample origins to be analyzed. Therefore, prudent careful selection of the methylation reagent should be carried out before the analysis.

BEFS-PPARγ2 cells incubated with trans-11 C18:1 exhibit more beneficial fatty acid synthesis

Responses of the PPARγ2 (an adipogenic lineage determinant) over-expressed immortalized bovine embryonic fibroblast cell line (BEFS-PPARγ2 cells) to trans-11 C18:1 (TVA) incubation were evaluated. BEFS-PPARγ2 cells were well differentiated. Stearoyl-CoA desaturase 1, an endoplasmic reticulum enzyme that can catalyze conversion of TVA into cis-9, trans-11 CLA, exhibited a significantly (p<0.05) higher mRNA expression after 4 h, compared with controls. Enzyme activity peaked, and was significantly (p<0.05) higher after 6 h, compared with controls. With extension of the incubation time, TVA absorption into cells was significantly (p<0.05) higher with significantly (p<0.05) more conversion into cis-9, trans-11 CLA, compared with shorter incubation times. TVA incubated cells exhibited significantly (p<0.05) higher levels of arachidonic, eicosapentaenoic, and docosahexaenoic acids than controls. BEFS-PPARγ2 cells can be used as a model system and TVA incubation is a good approach for research into cis-9, trans-11 CLA-fortified beef production.

Lithium chloride’s inhibition of 3T3-L1 cell differentiation by regulating the Wnt/β-catenin pathway and enhancing villin 2 expression

The aim of this study is to reveal the relation among villin 2, Wnt/β-catenin, and adipogenesis by adding appropriate lithium chloride (LiCl). The study comprises three parts: the selection of LiCl concentration, the effect of LiCl on adipocyte differentiation during and after differentiation induction. By comprehensively analyzing the results of the experiments, we proved that LiCl can inhibit adipocyte differentiation and enhance villin 2 and β-catenin expressions not only during differentiation induction but also after it. Moreover, villin 2 has a significant impact on β-catenin. We suggest that villin 2 may participate in Wnt/β-catenin signaling.

Physiological concentrations of trans-11 18:1 vaccenic acid suppress pro-inflammatory markers under acute inflammation in isolated ICR mice splenocytes

Direct influences of dietary trans-11 18:1 vaccenic acid (TVA) at physiological concentrations of 50-200 μM were evaluated for cell growth, cytotoxic activity, and cytokine production in leukocytes isolated from the mouse spleen. TVA supplementation for 24 h induced growth of splenocytes at concentrations of 50-200 μM, except for 100 μM. The cytokines TNFα, IFNγ, and IL-10 of splenocytes were stimulated by 100 μM TVA. Induced production of TNFα in splenocytes challenged with lipopolisaccharides was suppressed by 100 μM TVA. Physiological levels of TVA had direct effects on growth and cytokine production in splenocytes. Further in vivo studies are needed to improve understanding of the precise influence of trans fatty acids on production of pro-inflammatory markers under acute inflammation conditions.