Conjugated linoleic acid (CLA) is a potent cancer preventive agent in animal models. To date, all of the in vivo work with CLA has been done with a commercial free fatty acid preparation containing a mixture of c9,t11-, t10,c12- and c11,t13-isomers, although CLA in food is predominantly (80-90%) the c9,t11-isomer present in triacylglycerols. The objective of this study was to determine whether a high CLA butter fat has biological activities similar to those of the mixture of free fatty acid CLA isomers. The following four different endpoints were evaluated in rat mammary gland: 1) digitized image analysis of epithelial mass in mammary whole mount; 2) terminal end bud (TEB) density; 3) proliferative activity of TEB cells as determined by proliferating cell nuclear antigen immunohistochemistry; and 4) mammary cancer prevention bioassay in the methylnitrosourea model. It should be noted that TEB cells are the target cells for mammary chemical carcinogenesis. Feeding butter fat CLA to rats during the time of pubescent mammary gland development reduced mammary epithelial mass by 22%, decreased the size of the TEB population by 30%, suppressed the proliferation of TEB cells by 30% and inhibited mammary tumor yield by 53% (P < 0.05). Furthermore, all of the above variables responded with the same magnitude of change to both butter fat CLA and the mixture of CLA isomers at the level of CLA (0.8%) present in the diet. Interestingly, there appeared to be some selectivity in the uptake or incorporation of c9,t11-CLA over t10,c12-CLA in the tissues of rats given the mixture of CLA isomers. Rats consuming the CLA-enriched butter fat also consistently accumulated more total CLA in the mammary gland and other tissues (four- to sixfold increases) compared with those consuming free fatty acid CLA (threefold increases) at the same dietary level of intake. We hypothesize that the availability of vaccenic acid (t11-18:1) in butter fat may serve as the precursor for the endogenous synthesis of CLA via the Delta9-desaturase reaction. Further studies will be conducted to investigate other attributes of this novel dairy product.

Obese and sedentary persons have increased risk for cancer; inflammation is a hypothesized mechanism. We examined the effects of a caloric restriction weight loss diet and exercise on inflammatory biomarkers in 439 women. Overweight and obese postmenopausal women were randomized to 1-year: caloric restriction diet (goal of 10% weight loss, N=118), aerobic exercise (225 minutes/week of moderate-to-vigorous activity, N=117), combined diet+exercise (N=117) or control (N=87). Baseline and 1-year high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA), interleukin-6 (IL-6), leukocyte and neutrophil levels were measured by investigators blind to group. Inflammatory biomarker changes were compared using generalized estimating equations. Models were adjusted for baseline body mass index (BMI), race/ethnicity and age. 438 (N=1 in diet+exercise group was excluded) were analyzed. Relative to controls, hs-CRP decreased by geometric mean (95% confidence interval, p-value) 0.92mg/L (0.53–1.31, P<0.001) in the diet and 0.87mg/L (0.51–1.23, P<0.0001) in the diet+exercise groups. IL-6 decreased by 0.34pg/ml (0.13–0.55, P=0.001) in the diet and 0.32pg/ml (0.15–0.49, P<0.001) in the diet+exercise groups. Neutrophil counts decreased by 0.31×109/L (0.09–0.54, P=0.006) in the diet and 0.30×109/L (0.09–0.50, P=0.005) in the diet+exercise groups. Diet and diet+exercise participants with ≥5% weight loss reduced inflammatory biomarkers (hs-CRP, SAA, and IL-6) compared to controls. The diet and diet+exercise groups reduced hs-CRP in all subgroups of baseline BMI, waist circumference, CRP level, and fasting glucose. Our findings indicate that a caloric restriction weight loss diet with or without exercise reduces biomarkers of inflammation in postmenopausal women, with potential clinical significance for cancer risk reduction.

The epidemiologic evidence for associations between dietary factors and breast cancer is weak and etiologic mechanisms are often unclear. Exploring the role of dietary biomarkers with metabolomics can potentially facilitate objective dietary characterization, mitigate errors related to self-reported diet, agnostically test metabolic pathways, and identify mechanistic mediators. The aim of this study was to evaluate associations of diet-related metabolites with the risk of breast cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. We examined prediagnostic serum concentrations of diet-related metabolites in a nested case-control study in 621 postmenopausal invasive breast cancer cases and 621 matched controls in the multicenter PLCO cohort. We calculated partial Pearson correlations between 617 metabolites and 55 foods, food groups, and vitamin supplements on the basis of the 2015 Dietary Guidelines for Americans and derived from a 137-item self-administered food-frequency questionnaire. Diet-related metabolites (correlation < 1.47 × 10) were evaluated in breast cancer analyses. ORs for the 90th compared with the 10th percentile were calculated by using conditional logistic regression, with body mass index, physical inactivity, other breast cancer risk factors, and caloric intake controlled for (false discovery rate <0.2). Of 113 diet-related metabolites, 3 were associated with overall breast cancer risk (621 cases): caprate (10:0), a saturated fatty acid (OR: 1.77; 95% CI = 1.28, 2.43); γ-carboxyethyl hydrochroman (γ-CEHC), a vitamin E (γ-tocopherol) derivative (OR: 1.64; 95% CI: 1.18, 2.28); and 4-androsten-3β,17β-diol-monosulfate (1), an androgen (OR: 1.61; 95% CI: 1.20, 2.16). Nineteen metabolites were significantly associated with estrogen receptor (ER)-positive (ER) breast cancer (418 cases): 12 alcohol-associated metabolites, including 7 androgens and α-hydroxyisovalerate (OR: 2.23; 95% CI: 1.50, 3.32); 3 vitamin E (tocopherol) derivatives (e.g., γ-CEHC; OR: 1.80; 95% CI: 1.20, 2.70); butter-associated caprate (10:0) (OR: 1.81; 95% CI: 1.23, 2.67); and fried food-associated 2-hydroxyoctanoate (OR: 1.46; 95% CI: 1.03, 2.07). No metabolites were significantly associated with ER-negative breast cancer (144 cases). Prediagnostic serum concentrations of metabolites related to alcohol, vitamin E, and animal fats were moderately strongly associated with ER breast cancer risk. Our findings show how nutritional metabolomics might identify diet-related exposures that modulate cancer risk. This trial was registered at clinicaltrials.gov as NCT00339495.

Dietary energy restriction (DER) inhibits mammary carcinogenesis, yet mechanisms accounting for its protective activity have not been fully elucidated. In this study, we tested the hypothesis that DER exerts effects on intracellular energy sensing pathways, resulting in alterations of phosphorylated proteins that play a key role in the regulation of cancer. Experiments were conducted using the 1-methyl-1-nitrosourea-induced mammary cancer model in which rats were 0%, 20%, or 40% energy restricted during the postinitiation stage of carcinogenesis. Parallel experiments were done in non-carcinogen-treated rats in which effects of DER at 0%, 5%, 10%, 20%, or 40% in liver were investigated. In a DER dose-dependent manner, levels of Thr 172 phosphorylated AMP-activated protein kinase (AMPK) increased in mammary carcinomas with a concomitant increase in phosphorylated acetyl-CoA-carboxylase, a direct target of AMPK, the phosphorylation of which is regarded as an indicator of AMPK activity. Levels of phosphorylated mammalian target of rapamycin (mTOR) decreased with increasing DER, and down-regulation of mTOR activity was verified by a decrease in the phosphorylation state of two mTOR targets, 70-kDa ribosomal protein S6 kinase (p70S6K) and eukaryote initiation factor 4E binding protein 1 (4E-BP1). Coincident with changes in mTOR phosphorylation, levels of activated protein kinase B (Akt) were also reduced. Similar patterns were observed in mammary glands and livers of noncarcinogen-treated rats. This work identifies components of intracellular energy sensing pathways, specifically mTOR, its principal upstream regulators, AMPK and Akt, and its downstream targets, p70S6K and 4E-BP1, as candidate molecules on which to center mechanistic studies of DER. [Cancer Res 2008;68(13):5492-9]

The objective of the present study was to investigate whether the anticarcinogenic activity of conjugated linoleic acid (CLA) is affected by the amount and composition of dietary fat consumed by the host. Because the anticancer agent of interest is a fatty acid, this approach may provide some insight into its mechanism of action, depending on the outcome of these fat feeding experiments. For the fat level experiment, a custom formulated fat blend was used that simulates the fatty acid composition of the US diet. This fat blend was present at 10, 13.3, 16.7 or 20% by weight in the diet. For the fat type experiment, a 20% (w/w) fat diet containing either corn oil (exclusively) or lard (predominantly) was used. Mammary cancer prevention by CLA was evaluated using the rat dimethylbenz[a]anthracene model. The results indicated that the magnitude of tumor inhibition by 1% CLA was not influenced by the level or type of fat in the diet. It should be noted that these fat diets varied markedly in their content of linoleate. Fatty acid analysis showed that CLA was incorporated predominantly in mammary tissue neutral lipids, while the increase in CLA in mammary tissue phospholipids was minimal. Furthermore, there was no evidence that CLA supplementation perturbed the distribution of linoleate or other fatty acids in the phospholipid fraction. Collectively these carcinogenesis and biochemical data suggest that the cancer preventive activity of CLA is unlikely to be mediated by interference with the metabolic cascade involved in converting linoleic acid to eicosanoids. The hypothesis that CLA might act as an antioxidant was also examined. Treatment with CLA resulted in lower levels of mammary tissue malondialdehyde (an end product of lipid peroxidation), but failed to change the levels of 8-hydroxydeoxyguanosine (a marker of oxidatively damaged DNA). Thus while CLA may have some antioxidant function in vivo in suppressing lipid peroxidation, its anticarcinogenic activity cannot be accounted for by protecting the target cell DNA against oxidative damage. The finding that the inhibitory effect of CLA maximized at 1% (regardless of the availability. of linoleate in the diet) could conceivably point to a limiting step in the capacity to metabolize CLA to some active product(s) which is essential for cancer prevention.

While most data in the literature indicate that chemically-induced mammary carcinogenesis in the rat proceeds through morphologically identifiable stages, little quantitative data exist on the frequency of their occurrence. A carcinogen induction protocol is reported that defines conditions under which approximately 38% of detectable lesions in the abdominal-inguinal mammary glands were histologically classified as either intraductal proliferations or ductal carcinoma in situ. The remainder of the lesions were classified as carcinomas. This response was observed in a group of 30 female Sprague-Dawley rats injected i.p. with 50 mg 1-methyl-1-nitrosourea (MNU)/kg body wt at 21 days of age. The experiment was terminated 35 days following carcinogen administration. The methods used to prepare whole mounts and to identify, excise and process lesions in the whole mounts to permit histological classification are described in detail. This carcinogenesis protocol also induced a significant palpable tumor response. The first palpable tumor, histologically classified as an adenocarcinoma, was observed 30 days post carcinogen administration. When the experiment was terminated (35 days post MNU), the cumulative incidence of palpable carcinomas was 60%. The rapidity of the carcinogenic response was remarkable. Unlike the i.v. administration of 7,12-dimethylbenz[a]anthracene (DMBA) to rats of this age, MNU injection resulted in > 99% incidence of palpable mammary gland tumors that were malignant. The data reported in this paper confirm and support the pathogenetic pathway described for the induction of mammary tumors in the rat by DMBA. The induction of mammary carcinogenesis in immature animals described in this paper may be of value in the investigation of early morphologically identifiable stages of this disease process as well as providing an extremely rapid method for tumor induction.

While the Camellia sinensis cultivar and processing method are key factors that affect tea flavor and aroma, the chemical changes in nonvolatile components associated with the tea processing method using a single cultivar of C. sinensis have not been reported. Fresh leaves from C. sinensis Longjing 43 were subjected to six tea processing methods and evaluated by targeted and untargeted chromatographic procedures. On the basis of targeted assessment of the total catechin content, three clusters were identified: yellow−green, oolong−white−dark, and black. However, principal component analysis of the total tea metabolome identified four chemical phenotypes: green−yellow, oolong, black−white, and dark. Differences in the noncatechin components included amino acids and γ-aminobutyric acid, which increased in white tea, and dihydroxyphenylalanine, valine, betaine, and theophylline, which increased in dark tea. Overall, this study identified a wide range of chemicals that are affected by commonly used tea processing methods and potentially affect the bioactivity of various tea types.

Consumers have become increasingly aware of potential health benefits from diets rich in fruits and vegetables. While potato has not yet surfaced as a headline-grabber in this respect, there is increasing evidence that some genotypes may possess health attributes that warrant attention. Plant breeders rely on germplasm biodiversity to advance their programs and are also acutely aware of current marketing trends that relate to health attributes. Investigations of antioxidant properties for over 90 genotypes were conducted to characterize antioxidant profiles for the Colorado potato breeding program and to identify those especially rich in antioxidants. The objective was to summarize data based on total phenolics (TP), Trolox equivalent antioxidant capacity (TEAC) and vitamin C, as well as to provide LC/MS characterization of major phenolic compounds and glycoalkaloids for pigmented genotypes. Preliminary data from breast cancer cell culture inhibition studies were examined for relationships to in vitro chemical assays. Genotypes with red or purple skin and flesh consistently had the highest gallic acid equivalent TP, TEAC, and chlorogenic acid content. Baked tubers had lower TP levels, TEAC and vitamin C compared to uncooked, microwave cooked and boiled tubers. Environmental effects contributed year to year variation in TP and TEAC radical scavenging capacity. TP content increased after 6 to 7 months in refrigerated storage at 5±1°C in several highly pigmented, but not in white or yellow fleshed cultivars and selections. Major phenolic compounds, anthocyanins, and glycoalkaloid content were further investigated with LC/MS in six cultivars. The pigmented cultivars 'Purple Majesty' and 'Mountain Rose' contained considerably higher levels of chlorogenic acid isomers than the non-pigmented genotypes. In the nonpigmented genotypes, chlorogenic acid and glycolalkaloid content were highest in 'Rio Grande Russet'. Chlorogenic acid has been demonstrated to exhibit several desirable anticarcinogenic properties in recent biochemical investigations, as have several of the phenolic based anthocyanin pigments found in many colorful fruits and vegetables. Thus, comprehensive compositional profiles using LC/MS are of interest in characterizing germplasm for breeding purposes. Preliminary tests with phosphate buffered saline (PBS) extracts of baked tubers from six cultivars revealed that 'Rio Grande Russet' was most effective in inhibiting growth of breast cancer cultures MCF-7 and MDA-MB-468. 'Purple Majesty' inhibited to some extent, 'Mountain Rose' and 'Yukon Gold' had no inhibitory effect. A subsequent study with 21 genotypes where the initial extract was made with 80% acetone followed by drying and extraction in aqueous PBS differed from direct PBS extraction. Five genotypes including 'Russet Nugget' inhibited at 0.187% to 0.375% w/v of the cell culture Am. solution. However, IC 50 inhibition data was not strongly related to the in vitro chemical data for these cultivars.Resumen Los consumidores se han dado cuenta del potenc...