Myokines derived from contracting skeletal muscle suppress anabolism in MCF7 breast cancer cells by inhibiting mTOR.

There is strong evidence that physical activity has a profound protective effect against multiple types of cancer. Here, we show that this effect may be mediated by factors released from skeletal muscle during simulated exercise, , which suppress canonical anabolic signaling in breast cancer. We report attenuated growth of MCF7 breast cancer cells in the presence of a rodent-derived exercise conditioned perfusate, independent of prior exercise training.

Daidzein-metabolizing phenotypes in relation to bone density and body composition among premenopausal women in the United States.

Background: Bone density has been suggested as a marker of cumulative hormone exposure. Small studies also suggest that patterns of daidzein metabolism may be related to hormone concentrations. To our knowledge, no studies in premenopausal women have compared bone density by daidzein-metabolizing phenotypes in the absence of a soy intervention.

Fruit intake associated with urinary estrogen metabolites in healthy premenopausal women.

Urinary concentrations of 2:16-hydroxyestrone (2:16-OHE) approximate concentrations of 2-OHE and 16α -OHE in breast tissue. As estrogens are purported to be involved in breast cancer development, the 2:16-OHE ratio can provide an indication of estrogen metabolite exposure in the breast. With prior studies observing associations between urinary estrogen metabolites and dietary intake of fruits, vegetables, and fiber ascertained from food questionnaires, we examined associations between dietary factors ascertained through 3-day food records and urinary 2:16-OHE in 191 pre-menopausal healthy women.

Associations between polymorphisms in glucuronidation and sulfation enzymes and sex steroid concentrations in premenopausal women in the United States.

Glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGT) and sulfation, catalyzed by sulfotransferases (SULT), are pathways through which sex steroids are metabolized to less active compounds. These enzymes are highly polymorphic and genetic variants frequently result in higher or lower activity. The phenotypic effects of these polymorphisms on circulating sex steroids in premenopausal women have not yet been investigated.

Urinary estrogen metabolites and prostate cancer: a case-control study and meta-analysis.

Objective: To investigate prostate cancer (Pca) risk in relation to estrogen metabolism, expressed as urinary 2-hydroxyestrone (2-OHE1), 16alpha-hydroxyestrone (16alpha-OHE1) and 2-OHE1 to 16alpha-OHE1 ratio.

Methods: We conducted a case-control study within the Western New York Health Cohort Study (WNYHCS) from 1996 to 2001. From January 2003 through September 2004, we completed the re-call and follow-up of 1092 cohort participants.

Exercise effects on tumorigenesis in a p53-deficient mouse model of breast cancer.

Purpose: Physically active women have a reduced risk of breast cancer, but the dose of activity necessary and the role of energy balance and other potential mechanisms have not been fully explored in animal models. We examined treadmill and wheel running effects on mammary tumorigenesis and biomarkers in p53-deficient (p53(+/-)):MMTV-Wnt-1 transgenic mice.

Methods: Female mice (9 wk old) were randomly assigned to the following groups in experiment 1: treadmill exercise 5 d x wk(-1), 45 min x d(-1), 5% grade at 20 m x min(-1), approximately 0.

Associations between endogenous sex hormone levels and mammographic and bone densities in premenopausal women.

Purpose: Mammographic breast and bone mineral densities (BMD) have been associated with luteal phase hormone concentrations in premenopausal women. We assessed the associations of breast and bone densities with follicular phase hormones and sex hormone binding globulin (SHBG) in premenopausal women, given that follicular phase hormones have been shown to be positively associated with premenopausal breast cancer risk.

Methods: One hundred and ninety-two 40-45-year-old women provided a spot urine and/or blood sample during the follicular phase.

Daidzein-metabolizing phenotypes in relation to mammographic breast density among premenopausal women in the United States.

Background: Mammographic breast density is an established marker of breast cancer risk, and is hormonally sensitive. Studies suggest that production of the daidzein metabolites equol and O-Desmethylangolensin (ODMA) may be associated with hormones and hormonally mediated factors, but few studies have assessed relationships between the capacity to produce these metabolites and breast density.

Objective: To evaluate the relationship between equol- and ODMA-producer phenotypes and breast density in premenopausal women in the United States.

Daidzein-metabolizing phenotypes in relation to serum hormones and sex hormone binding globulin, and urinary estrogen metabolites in premenopausal women in the United States.

Objective: Blood and urine concentrations of hormones are implicated in the etiology of some cancers. Small studies have assessed relationships between production of the daidzein metabolites equol and O-desmethylangolensin (ODMA) and hormones, but findings are unclear. We evaluated relationships between daidzein-metabolizing phenotypes and follicular phase concentrations of estrogens, androgens, sex hormone binding globulin (SHBG), and urinary estrogen metabolites in premenopausal women.

Effect of energy deficiency on estrogen metabolism in premenopausal women.

Purpose: Physical activity has been associated with decreased breast cancer risk, potentially through changes in estrogen metabolism. Two-hydroxyestrone (2-OHE1) and 16alpha-hydroxyestrone (16alpha-OHE1) have different biological properties, and the ratio of these metabolites (2/16) has been proposed to predict breast cancer risk. Diet and exercise have been found to influence estrogen metabolism, particularly when a state of negative energy balance is achieved.

Effects of aerobic exercise training on estrogen metabolism in premenopausal women: a randomized controlled trial.

Background: Regular physical activity may alter estrogen metabolism, a proposed biomarker of breast cancer risk, by shifting metabolism to favor production of 2-hydroxyestrone (2-OHE1). Few studies, however, have examined this question using a randomized controlled trial.

Purpose: To examine the effects of 12 weeks of aerobic exercise training on 2-OHE1 and 16alpha-hydroxyestrone (16alpha-OHE1) in premenopausal women.

Resistance exercise training attenuates alcohol-induced cardiac oxidative stress.

Background: Myocardial oxidative stress is believed to play an important role in the pathogenesis of alcoholic cardiomyopathy. Strenuous physical exercise has been shown to increase or decrease myocardial oxidative stress depending on the mode and duration of the exercise intervention. Given the possibility of individuals to engage in both alcohol consumption and weight-training exercise, we have examined the effect of resistance exercise training and chronic alcohol consumption on myocardial oxidative stress in rats.

Chronic alcohol intake, resistance training, and muscle androgen receptor content.

Introduction: Chronic alcohol intake and resistance training (RT) have opposite effects on muscle physiology.

Purpose: This study examined the effect of chronic alcohol intake on androgen receptor (AR) content in skeletal muscle to determine whether this effect was influenced by RT.

Methods: A total of 48 male Sprague Dawley(R) rats (mass = 456 +/- 1 g; mean +/- SE) were divided into five groups: baseline (N = 8), sedentary + alcohol (Sed-Al) (N = 8), sedentary + normal diet (Sed-Nml) (N = 8), exercise + alcohol (Ex-Al) (N = 12), and exercise + normal diet (Ex-Nml) (N = 12).

The relationship between physical activity and 2-hydroxyestrone, 16alpha-hydroxyestrone, and the 2/16 ratio in premenopausal women (United States).

Objectives: Estrogen is metabolized in the body through two mutually exclusive pathways yielding metabolites with different biological activities: the low estrogenic 2-hydroxyestrone (2-OHE1) and the highly estrogenic 16alpha-hydroxyestrone (16alpha-OHE1). The ratio of these metabolites (2/16) may be predictive of risk for developing breast cancer. Early evidence has demonstrated that exercise may alter estrogen metabolism to favor the weak estrogen, 2-OHE1.

Associations between aerobic fitness and estrogen metabolites in premenopausal women.

Unlabelled: Chronic physical activity may alter estrogen metabolism, a proposed biomarker of breast cancer risk, by causing a shift toward higher 2-OHE1 and lower 16alpha-OHE1 levels.

Purpose: To investigate the association between an objective indicator of chronic exercise, aerobic fitness, and 2-OHE1 and 16alpha-OHE1 in premenopausal women.

Methods: Women with high aerobic fitness (N=17; VO2max>or=48 mL.

Training enhances vascular relaxation after chemotherapy-induced vasoconstriction.

Purpose: Although evidence is accumulating that suggests regular moderate physical activity improves physiological and psychological well-being of cancer patients undergoing chemotherapy, the mechanisms involved remain unclear. Therefore, the purpose of this study was to determine if exercise training improves endothelium-dependent vasodilation after exposure to the chemotherapeutic agent 5-fluorouracil (5-FU).

Methods: Rats were injected with N-methyl-N-nitrosourea (MNU) and assigned to either exercise (EX; treadmill running, 20-25 m.

Physical activity and cancer prevention--mechanisms.

Purpose: This paper presents potential mechanisms by which exercise or physical activity may affect cancer development.

Methods: Analysis of published and unpublished experimental and epidemiological data from the cancer-activity literature and from other fields of study are compiled to provide a summary of potential mechanisms by which exercise may mediate cancer development.

Results: Exercise appears to have a beneficial effect relative to cancer development, and the reader is referred to other sections of this symposium.

Attenuation of homocysteine-induced endothelial dysfunction by exercise training.

Hyperhomocysteinemia is an independent risk factor for the development of cardiovascular disease. Exposure of endothelial cells to elevated levels of homocysteine (HCY) results in decreased availability of nitric oxide (NO) and impaired vascular function, both of which are early events in atherogenesis. Exercise training improves vascular function by increasing endothelial NO production secondary to an increase in the enzyme responsible for its synthesis, endothelial nitric oxide synthase (eNOS).

Comparative effects of long-term continuous release of 16 alpha-hydroxyestrone and 17 beta-estradiol on bone, uterus, and serum cholesterol in ovariectomized adult rats.

16Alpha-hydroxyestrone (16alpha-OHE(1)), an endogenous estrogen metabolite, is associated with increased bone density in postmenopausal women. This study was designed to evaluate the long-term activity of this metabolite on bone, uterus, and serum cholesterol in an animal model for postmenopausal bone loss. A preliminary dose-response study performed in weanling rats determined 2000 microg/kg/day to be the optimal dose of 16alpha-OHE(1) for studying estrogenic effect on bone.

The effects of chronic alcohol consumption and exercise on the skeleton of adult male rats.

Background: Lifestyle factors are known to affect skeletal development and integrity. Specifically, running has been reported to increase risk of fatigue fractures, whereas chronic alcohol consumption has been shown to reduce bone formation and bone mass. The combined effect of exercise and alcohol on the skeleton has yet to be explored, although alcohol consumption is common among certain physically active populations (e.