Insulin-like growth factor I (IGF-I) and IGF binding protein-1 modulate prostate cancer cell growth and apoptosis: possible mediators for the effects of diet and exercise on cancer cell survival

Effects of high-intensity interval training on cardiometabolic biomarkers in patients with prostate cancer undergoing active surveillance: a randomized controlled trial

PURPOSE

To report the effects of a 12-week high-intensity interval training (HIIT) program on cardiometabolic biomarkers in patients with prostate cancer on active surveillance (AS) from the Exercise During Active Surveillance for Prostate Cancer (ERASE) Trial.

METHODS

Fifty-two men with prostate cancer on AS were randomized to either an exercise (HIIT; n = 26) or usual care (UC; n = 26) group. The HIIT intervention consisted of progressive, supervised, aerobic HIIT at an intensity of 85 to 95% VO2peak for 28 to 40 min per session performed three times/week for 12 weeks. Blood samples were collected at baseline and postintervention to analyze cardiometabolic biomarkers. Analysis of covariance was used to examine between-group mean differences.

RESULTS

Blood data were obtained from 49/52 (94%) participants at postintervention. Participants were aged 63.4 ± 7.1 years and 40% were obese. The HIIT group attended 96% of the planned exercise sessions. No significant between-group changes in weight were observed after the intervention. Compared to UC, HIIT significantly improved total cholesterol (-0.40 mmol/L; 95% confidence interval[CI], -0.70 to -0.10; p = 0.011), non-high-density lipoprotein-c (-0.35 mmol/L; 95% CI, -0.60 to -0.11; p = 0.006), insulin (-13.6 pmol/L; 95% CI, -25.3 to -1.8; p = 0.025), insulin-like growth factor (IGF)-1 (-15.0 ng/mL; 95% CI, -29.9 to -0.1; p = 0.048), and IGF binding protein (IGFBP)-3 (152.3 ng/mL; 95% CI, 12.6 to 292.1; p = 0.033). No significant differences were observed for fasting glucose, HbA1c, other lipid markers, IGFBP-1, adiponectin, and leptin.

CONCLUSIONS

The ERASE Trial showed that a 12-week aerobic HIIT program improved several cardiometabolic biomarkers in patients with prostate cancer on AS that may contribute to cardiovascular health benefits and potentially influence signaling pathways in the progression of prostate cancer. Further research is needed to confirm the effects of exercise on cardiometabolic markers in men with prostate cancer on AS and determine if these effects are associated with improved long-term clinical outcomes.

Suppressive effects of exercise-conditioned serum on cancer cells: A narrative review of the influence of exercise mode, volume, and intensity

Cancer is a major cause of morbidity and mortality worldwide, and the incidence is increasing, highlighting the need for effective strategies to treat this disease. Exercise has emerged as fundamental therapeutic medicine in the management of cancer, associated with a lower risk of recurrence and increased survival. Several avenues of research demonstrate reduction in growth, proliferation, and increased apoptosis of cancer cells, including breast, prostate, colorectal, and lung cancer, when cultured by serum collected after exercise in vitro (i.e., the cultivation of cancer cell lines in an experimental setting, which simplifies the biological system and provides mechanistic insight into cell responses). The underlying mechanisms of exercise-induced cancer suppressive effects may be attributed to the alteration in circulating factors, such as skeletal muscle-induced cytokines (i.e., myokines) and hormones. However, exercise-induced tumor suppressive effects and detailed information about training interventions are not well investigated, constraining more precise application of exercise medicine within clinical oncology. To date, it remains unclear what role different training modes (i.e., resistance and aerobic training) as well as volume and intensity have on exercise-conditioned serum and its effects on cancer cells. Nevertheless, the available evidence is that a single bout of aerobic training at moderate to vigorous intensity has cancer suppressive effects, while for chronic training interventions, exercise volume appears to be an influential candidate driving cancer inhibitory effects regardless of training mode. Insights for future research investigating training modes, volume and intensity are provided to further our understanding of the effects of exercise-conditioned serum on cancer cells.

Mechanisms Underlying the Rarity of Skeletal Muscle Cancers

Skeletal muscle (SKM), despite comprising ~40% of body mass, rarely manifests cancer. This review explores the mechanisms that help to explain this rarity, including unique SKM architecture and function, which prohibits the development of new cancer as well as negates potential metastasis to SKM. SKM also presents a unique immune environment that may magnify the anti-tumorigenic effect. Moreover, the SKM microenvironment manifests characteristics such as decreased extracellular matrix stiffness and altered lactic acid, pH, and oxygen levels that may interfere with tumor development. SKM also secretes anti-tumorigenic myokines and other molecules. Collectively, these mechanisms help account for the rarity of SKM cancer.

A home-based lifestyle intervention program reduces the tumorigenic potential of triple-negative breast cancer cells

Translational research for the evaluation of physical activity habits and lifestyle modifications based on nutrition and exercise has recently gained attention. In this study, we evaluated the effects of serum samples obtained before and after a 12-week home-based lifestyle intervention based on nutrition and exercise in breast cancer survivors in terms of modulation of the tumorigenic potential of breast cancer cells. The home-based lifestyle intervention proposed in this work consisted of educational counselling on exercise and nutritional behaviors and in 12 weeks of structured home-based exercise. Triple-negative breast cancer cell line MDA-MB-231 was cultured in semi-solid medium (3D culture) with sera collected before (PRE) and after (POST) the lifestyle intervention program. Spheroid formation was evaluated by counting cell colonies after 3 weeks of incubation. Results show a slight but significant reduction of spheroid formation induced by serum collected POST in comparison to those obtained PRE. Moreover, statistical analyses aimed to find physiologic and metabolic parameters associated with 3D cell proliferation revealed the proliferative inducer IGF-1 as the only predictor of cell tumorigenic potential. These results highlight the importance of lifestyle changes for cancer progression control in a tertiary prevention context. Translational research could offer a useful tool to identify metabolic and physiological changes induced by exercise and nutritional behaviors associated with cancer progression and recurrence risk.

Association between IGFBP1 expression and cancer risk: A systematic review and meta-analysis

Background

The results regarding the association between insulin-like growth factor binding protein 1 (IGFBP1) expression and cancer risk were controversial. We performed a meta-analysis to provide novel evidence on relationship between IGFBP1 expression and cancer risk.

Methods

PubMed, Embase, Cochrane library and Web of science were searched for relevant cohort and case-control studies exploring the relationship between IGFBP1 expression and cancer risk. Odds ratios (ORs) were pooled in this meta-analysis using random model. Subgroup analyses were performed based on ethnicity, tumor types, publication year, study type, Newcastle-Ottawa Scale (NOS) score and sex.

Results

A total of 27 studies including 16 cohort and 11 case-control studies were identified by literature search. No significant association was found between IGFBP1 expression and risk of various cancers [0.90, 95% confidence interval (CI): 0.79, 1.03]. The overall results showed that the pooled ORs were 0.71 (95% CI: 0.57, 0.88] for prostate cancer risk and 0.66 (95%CI: 0.44, 0.99) for colorectal cancer (CRC) risk. However, there is no significant association between IGFBP1 expression and risk for ovarian cancer (1.70, 95%CI: 0.41, 6.99), breast cancer (1.02, 95%CI: 0.85, 1.23), endometrial cancer (1.19, 95%CI: 0.64, 2.21), colorectal adenoma (0.93; 95%CI: 0.81, 1.07), lung cancer (0.81, 95%CI: 0.39, 1.68) or multiple myeloma (1.20, 95%CI: 0.98, 1.47).

Conclusion

In this study, compared with individuals at low IGFBP1 expression adjusted for age, smoking status, alcohol intake and so on, risk of the prostate cancer and CRC were decreased among individuals of high IGFBP1 expression. There needs further study to confirm this issue.

Post-Exercise Serum from Humans Influences the Biological Tug of War of APP Processing in Human Neuronal Cells

Neurodegenerative diseases such as Alzheimer's disease (AD) are becoming more prevalent in our aging society. One specific neuropathological hallmark of this disease is the accumulation of amyloid-β (Aβ) peptides, which aggregate to form extra-neuronal plaques. Increased Aβ peptides are often observed well before symptoms of AD develop, highlighting the importance of targeting Aβ producing pathways early on in disease progression. Evidence indicates that exercise has the capacity to reduce Aβ peptide production in the brain however the mechanisms remain unknown. Exercise-induced signaling mediators could be the driving force behind some of the beneficial effects observed in the brain with exercise. The purpose of this study was to examine if post-exercise serum and the factors it contains can alter neuronal APP processing. Human SH-SY5Y neuronal cells were differentiated with retinoic acid for 5 days and treated with 10% pre- or post-exercise serum from humans for 30 minutes. Cells were collected for analysis of acute (30 minutes; n=6) or adaptive (24 hours post-treatment; n=6) responses. There were no statistical differences in ADAM10 and BACE1 mRNA or protein expression with post-exercise serum treatment at either time point. However, there was an increase in the ratio of sAPPa to sAPPβ protein content (p=0.05) after 30 minutes of post-exercise serum treatment. Additionally, 30 minutes of post-exercise serum treatment increased ADAM10 (p=0.01) and BACE1 (p=0.02) activity. These findings suggest that post-exercise serum modulates important enzymes involved in APP processing, pushing the cascade towards the non-amyloidogenic arm.

Myokine Expression and Tumor-Suppressive Effect of Serum after 12 wk of Exercise in Prostate Cancer Patients on ADT

PURPOSE

Although several mechanisms have been proposed for the tumor-suppressive effect of exercise, little attention has been given to myokines, even though skeletal muscle is heavily recruited during exercise resulting in myokine surges. We measured resting serum myokine levels before and after an exercise-based intervention and the effect of this serum on prostate cancer cell growth.

METHODS

Ten prostate cancer patients undertaking androgen deprivation therapy (age, 73.3 ± 5.6 yr) undertook a 12-wk exercise-based intervention including supervised resistance training, self-directed aerobic exercise, and protein supplementation. Body composition was assessed by dual-energy x-ray absorptiometry and muscle strength by the one-repetition maximum method. Fasting blood was collected at baseline and postintervention, and serum levels of myokines-secreted protein acidic and rich in cysteine, oncostatin M (OSM), decorin, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 (IGFBP-3)-were measured. The growth of the prostate cancer cell line DU145 with baseline and postintervention serum was measured.

RESULTS

Body weight (P = 0.011), fat mass (P = 0.012), and percent body fat (P = 0.033) were reduced, whereas percent lean mass (P = 0.001) increased, as did strength (leg press, P = 0.006; chest press, P = 0.020) across the intervention. Serum OSM levels (P = 0.020) and relative serum OSM levels (P = 0.020) increased compared with baseline. A significant reduction in DU145 Cell Index (P = 0.012) and growth rate (P = 0.012) was observed after applying postintervention serum compared with baseline serum.

CONCLUSIONS

This study provides evidence for enhanced myokine expression and tumor-suppressive effects of serum from chronically exercise-trained prostate cancer patients on androgen deprivation therapy.

Exercise in advanced prostate cancer elevates myokine levels and suppresses in-vitro cell growth

BACKGROUND

Altering the systemic milieu through exercise has been proposed as a potential mechanism underlying exercise-driven tumour suppression. It is not yet known whether men with advanced prostate cancer can elicit such adaptations following a program of exercise. The purpose is to examine myokine levels of serum acquired from metastatic castrate-resistant prostate cancer (mCRPC) patients recruited to the INTERVAL-GAP4 trial before and after 6 months of exercise and its tumour-suppressive effect.

METHODS

Twenty-five men with mCRPC (age = 74.7 ± 7.1 yrs) were randomised to supervised multimodal (aerobic and resistance) exercise (EX) or self-directed exercise control group (CON). Body composition was assessed using dual-energy x-ray absorptiometry (DXA), and fasting blood in a rested state was collected at baseline and at 6 months. Serum levels of myokines (SPARC, OSM, decorin, IGF-1, and IGFBP-3) were measured. Serum was applied to the prostate cancer cell line DU145, and growth was assessed for 72 h.

RESULTS

No significant change in body composition was observed. Adjusted serum OSM (P = 0.050) and relative OSM (P = 0.083), serum SPARC (P = 0.022) and relative SPARC (P = 0.025) increased in EX compared to CON. The area under curve (AUC) over 72 h showed a significant reduction in DU145 growth after applying post-intervention serum from the EX vs CON (P = 0.029).

CONCLUSION

Elevated myokine expressions and greater tumour-suppressive effects of serum after 6 months of periodised and autoregulated supervised exercise was observed in men with mCRPC. Exercise-induced systemic changes may slow disease progression in men with advanced prostate cancer.

Exercise-induced myokines and their effect on prostate cancer

Exercise is recognized by clinicians in the field of clinical oncology for its potential role in reducing the risk of certain cancers and in reducing the risk of disease recurrence and progression; yet, the underlying mechanisms behind this reduction in risk are not fully understood. Studies applying post-exercise blood serum directly to various types of cancer cell lines provide insight that exercise might have a role in inhibiting cancer growth via altered soluble and cell-free blood contents. Myokines, which are cytokines produced by muscle and secreted into the bloodstream, might offer multiple benefits to cellular metabolism (such as a reduction in insulin resistance, improved glucose uptake and reduced adiposity), and blood myokine levels can be altered with exercise. Alterations in the levels of myokines such as IL-6, IL-15, IL-10, irisin, secreted protein acidic risk in cysteine (SPARC), myostatin, oncostatin M and decorin might exert a direct inhibitory effect on cancer growth via inhibiting proliferation, promoting apoptosis, inducing cell-cycle arrest and inhibiting the epithermal transition to mesenchymal cells. The association of insulin resistance, hyperinsulinaemia and hyperlipidaemia with obesity can create a tumour-favourable environment; exercise-induced myokines can manipulate this environment by regulating adipose tissue and adipocytes. Exercise-induced myokines also have a critical role in increasing cytotoxicity and the infiltration of immune cells into the tumour.

Anti-carcinogenic effects of exercise-conditioned human serum: evidence, relevance and opportunities

Regular physical activity reduces the risk of several site-specific cancers in humans and suppresses tumour growth in animal models. The mechanisms through which exercise reduces tumour growth remain incompletely understood, but an intriguing and accumulating body of evidence suggests that the incubation of cancer cells with post-exercise serum can have powerful effects on key hallmarks of cancer cell behaviour in vitro. This suggests that exercise can impact tumour biology through direct changes in circulating proteins, RNA molecules and metabolites. Here, we provide a comprehensive narrative overview of what is known about the effects of exercise-conditioned sera on in vitro cancer cell behaviour. In doing so, we consider the key limitations of the current body of literature, both from the perspective of exercise physiology and cancer biology, and we discuss the potential in vivo physiological relevance of these findings. We propose key opportunities for future research in an area that has the potential to identify key anti-oncogenic protein targets and optimise physical activity recommendations for cancer prevention, treatment and survivorship.

Gut Microbiota-Derived Short-Chain Fatty Acids Promote Prostate Cancer Growth via IGF1 Signaling

Excessive intake of animal fat and resultant obesity are major risk factors for prostate cancer. Because the composition of the gut microbiota is known to change with dietary composition and body type, we used prostate-specific Pten knockout mice as a prostate cancer model to investigate whether there is a gut microbiota-mediated connection between animal fat intake and prostate cancer. Oral administration of an antibiotic mixture (Abx) in prostate cancer-bearing mice fed a high-fat diet containing a large proportion of lard drastically altered the composition of the gut microbiota including Rikenellaceae and Clostridiales, inhibited prostate cancer cell proliferation, and reduced prostate Igf1 expression and circulating insulin-like growth factor-1 (IGF1) levels. In prostate cancer tissue, MAPK and PI3K activities, both downstream of the IGF1 receptor, were suppressed by Abx administration. IGF1 directly promoted the proliferation of prostate cancer cell lines DU145 and 22Rv1 in vitro. Abx administration also reduced fecal levels of short-chain fatty acids (SCFA) produced by intestinal bacteria. Supplementation with SCFAs promoted tumor growth by increasing IGF1 levels. In humans, IGF1 was found to be highly expressed in prostate cancer tissue from obese patients. In conclusion, IGF1 production stimulated by SCFAs from gut microbes influences the growth of prostate cancer via activating local prostate MAPK and PI3K signaling, indicating the existence of a gut microbiota-IGF1-prostate axis. Disrupting this axis by modulating the gut microbiota may aid in prostate cancer prevention and treatment. SIGNIFICANCE: These results suggest that intestinal bacteria, acting through short-chain fatty acids, regulate systemic and local prostate IGF1 in the host, which can promote proliferation of prostate cancer cells.

Anti-carcinogenic effects of exercise-conditioned human serum: evidence, relevance and opportunities

Regular physical activity reduces the risk of several site-specific cancers in humans and suppresses tumour growth in animal models. The mechanisms through which exercise reduces tumour growth remain incompletely understood, but an intriguing and accumulating body of evidence suggests that the incubation of cancer cells with post-exercise serum can have powerful effects on key hallmarks of cancer cell behaviour in vitro. This suggests that exercise can impact tumour biology through direct changes in circulating proteins, RNA molecules and metabolites. Here, we provide a comprehensive narrative overview of what is known about the effects of exercise-conditioned sera on in vitro cancer cell behaviour. In doing so, we consider the key limitations of the current body of literature, both from the perspective of exercise physiology and cancer biology, and we discuss the potential in vivo physiological relevance of these findings. We propose key opportunities for future research in an area that has the potential to identify key anti-oncogenic protein targets and optimise physical activity recommendations for cancer prevention, treatment and survivorship.

Regular Voluntary Running Inhibits Androgen-Independent Prostate Cancer Growth in Mice

INTRODUCTION

Benefits of regular physical exercise were demonstrated as preventive and coadjuvant nonpharmacological anticancer therapy. However, the role of exercise in modulating prostate cancer behavior has yet to be established.

METHODS

Prostate tumors were induced in C57BL/6 male mice (n = 28) by subcutaneous inoculation of a suspension of murine androgen-independent RM1 cells (1.5 × 105 cells/500 μL phosphate-buffered saline) in the dorsal region. Mice were randomly allocated into 2 study groups: sedentary tumor-induced (n = 14) and exercised tumor-induced (n = 14). Exercise consisted of voluntary running in wheeled cages. Mice (n = 7 per group) were sacrificed either 14 or 28 days after cell inoculation to evaluate tumor weight and percentage of area occupied by immunohistochemistry stained cells for Ki-67 and TdT-mediated dUTP-biotin nick end labeling, used as surrogate markers of cell proliferation and apoptosis, respectively.

RESULTS

Compared with sedentary tumor-induced mice, the tumors developed by exercised tumor-induced mice were significantly smaller at 14 days (0.17 [0.12] g vs 0.48 [0.24] g, P < .05) and at 28 days (0.92 [0.73] g vs 2.09 [1.31] g, P < .05), with smaller Ki-67 and greater TdT-mediated dUTP-biotin nick end-labeling stained areas (P < .05).

CONCLUSION

These results suggest that regular voluntary running inhibits prostate cancer cell growth by reducing cell proliferation and enhancing apoptosis.

Physical activity, dietary protein and insulin-like growth factor 1: Cross-sectional analysis utilising UK Biobank

BACKGROUND

Insulin-like growth factor-I (IGF-1) is an anabolic hormone that stimulates cell growth and division. The effects of IGF-1 may be beneficial (muscle growth/repair) or detrimental (increased risk of several types of cancer and mortality) for health. Dietary protein and physical activity are thought to be factors that modulate IGF-1.

OBJECTIVE

This study analysed the relationships dietary protein vs IGF-1 and physical activity vs IGF-1 independently with a large sample size, and determined if/how physical activity affected the association between dietary protein and IGF-1 in healthy adults.

METHODS

Regression models were used to assess the association between dietary protein and/or physical activity on serum IGF-1 in a cross-sectional sample of 60,677 healthy adults that were enrolled in the UK Biobank project.

RESULTS

Dietary protein was positively associated with IGF-1 (0.030 nmol/L;95%CI 0.027-0.033;p < 0.001). Individuals undertaking 10-50 excess MET h/week of physical activity had 0.129 nmol/L greater IGF-1 than participants completing less than 10 excess MET h/week (95%CI 0.028-0.230). The "high" category of physical activity (>50 excess MET h/week) was not correlated with IGF-1 (-0.055 nmol/L;95%CI -0.185-0.076). When dietary protein and physical activity were included in the same model, physical activity did not change the relationship between dietary protein and IGF-1, nor visa-versa.

CONCLUSIONS

The positive association between dietary protein and IGF-1 was not influenced by physical activity. The former association was stronger than the latter. Thus, when seeking to adjust IGF-1 for possible health concerns, regulating dietary protein may be more pertinent than physical activity as a primary intervention.

Conditional Knockdown of Osteopontin Inhibits Breast Cancer Skeletal Metastasis

High osteopontin (OPN) expression is linked to breast cancer bone metastasis. In this study we modulated osteopontin levels conditionally and investigated any related antineoplastic effects. Therefore, we established cell clones from human breast cancer MDA-MB-231 cells, in which the expression of OPN is regulated by the Tet-Off tet-off system. These cells, which conditionally express a specific miRNA targeting OPN, were used for in vitro studies as well as for a bone metastasis model in nude rats. Changes in whole-genome expression elicited by conditional OPN knockdown and vesicle formation were also analyzed. The alkylphosphocholine erufosine was used for combination therapy. Conditional OPN knockdown caused mild anti-proliferative, but more intensive anti-migratory and anti clonogenic effects, as well as partial and complete remissions of soft tissue and osteolytic lesions. These effects were associated with specific gene and protein expression modulations following miRNA-mediated OPN knockdown. Furthermore, high levels of OPN were detected in vesicles derived from rats harboring breast cancer skeletal metastases. Finally, the combination of OPN inhibition and erufosine treatment caused an additive reduction of OPN levels in the investigated breast cancer cells. Thus, knockdown of OPN alone or in combination with erufosine is a promising strategy in breast cancer skeletal metastasis treatment.

Higher baseline dietary fat and fatty acid intake is associated with increased risk of incident prostate cancer in the SABOR study

BACKGROUND

To study the association of nutrient intake measured by baseline food frequency questionnaire and risk of subsequent prostate cancer (PCa) in the SABOR (San Antonio Biomarkers of Risk) cohort study.

METHODS

After IRB approval, more than 1903 men enrolled in a prospective cohort from 2000 to 2010 as part of the SABOR clinical validation site for the National Cancer Institute Early Detection Research Network. Food and nutrient intakes were calculated using a Food Frequency Questionnaire. Cox proportional hazards modeling and covariate-balanced propensity scores were used to assess the associations between all nutrients and PCa.

RESULTS

A total of 229 men were diagnosed with PCa by prostate biopsy. Among all nutrients, increased risk of PCa was associated with intake of dietary fat scaled by the total caloric intake, particularly saturated fatty acid (SFA) [HR 1.19; 95% CI, 1.07-1.32), P value < 0.001, False discovery rate (FDR) 0.047] and trans fatty acid (TFA) [HR per quintile 1.21; (95% CI) (1.08-1.35), P < 0.001, FDR 0.039]. There was an increased risk of PCa with increasing intake of monounsaturated fatty acid (MUFA) (HR per quintile 1.14; 95% CI 1.03-1.27, P = 0.01, FDR 0.15) and cholesterol [HR per quintile 1.13; 95% confidence interval (95% CI) (1.02-1.26), P-value 0.02, FDR 0.19].

CONCLUSION

After examining a large, population-based cohort for PCa diagnosis, we identified dietary total fat and certain fatty acids as associated with increased risk of PCa. We found no factors that were protective from PCa. Dietary modification of fatty acid intake may reduce risk of PCa.

Pre-diagnostic carbohydrate intake and treatment failure after radical prostatectomy for early-stage prostate cancer

PURPOSE

An association between dietary carbohydrate intake and prostate cancer (PCa) prognosis is biologically plausible, but data are scarce. This prospective cohort study examined the relation between pre-diagnostic carbohydrate intake and treatment failure following radical prostatectomy for clinically early-stage PCa.

METHODS

We identified 205 men awaiting radical prostatectomy and assessed their usual dietary intake of carbohydrates using the 110-item Block food frequency questionnaire. We also evaluated carbohydrate intake quality using a score based on the consumption of sugars relative to fiber, fat, and protein. Logistic regression analyzed their associations with the odds of treatment failure, defined as a detectable and rising serum prostate-specific antigen (PSA) or receiving androgen deprivation therapy (ADT) within 2 years.

RESULTS

Sucrose consumption was associated with a higher odds and fiber consumption with a lower odds of ADT after accounting for age, race/ethnicity, body mass index, and tumor characteristics (odds ratio [OR] (95% confidence interval [CI]) 5.68 (1.71, 18.9) for 3rd vs. 1st sucrose tertile and 0.88 (0.81, 0.96) per gram of fiber/day, respectively). Increasing carbohydrate intake quality also associated with a lower odds of ADT (OR (95% CI) 0.78 (0.66, 0.92) per unit increase in score, range 0-12).

CONCLUSIONS

Pre-diagnostic dietary carbohydrate intake composition and quality influence the risk of primary treatment failure for early-stage PCa. Future studies incorporating molecular aspects of carbohydrate metabolism could clarify possible underlying mechanisms.

Metabolic syndrome and prostatic disease: potentially role of polyphenols in preventive strategies. A review

Benign prostatic hyperplasia and prostate cancer are two common urological diseases of the elderly. Scientific community has always looked for a link that could explain the correlation between the two diseases and the role of chronic inflammation in the pathogenesis of BPH and PCa. As shown by the reports of the two diseases relationship with oxidative stress and metabolic syndrome, the use of compounds with antioxidant action could therefore affect both the symptoms and their onset. Polyphenols appear to act not only against oxidative stress but also at different levels. The aim of this review is to evaluate the role of the most important polyphenols on these two urological diseases. As antioxidants these compounds seems to have a direct action on the cell cycle and hormone function, important for both prostate cancer and BPH. Despite a large number of articles about the relationship of the polyphenols with prostate cancer, very little evidence exists for BPH. Additional clinical trials or meta-analysis are necessary on this topic.

Inhibition of Human Lung Cancer Cell Proliferation and Survival by Post-Exercise Serum Is Associated with the Inhibition of Akt, mTOR, p70 S6K, and Erk1/2

Non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer cases, and for the most cancer-related deaths. The survival pathway of Akt, its downstream effectors, the mammalian target of rapamycin (mTOR) and ribosomal protein S6 kinase (p70 S6K), and the Ras-extracellular signal-regulated kinase (Erk1/2) pathways are activated in cancer leading to cell survival and growth. Thus, approaches that inhibit these signaling molecules may prove useful in the fight against lung cancer. Exercise is associated with health benefits and a limited number of studies indicate that serum from physically active individuals inhibit mammary and prostate cancer cell growth. In this study, we examined the effects of post exercise serum on proliferation, survival, and signaling cascades of human NSCLC cells. Blood was collected from male subjects prior to, 5 min, 1 h, and 24 h after a single bout of high intensity interval exercise on a cycle ergometer. Exposure of NSCLC cells to post exercise serum resulted in the inhibition of cell proliferation and survival, as well as significant reduction of phosphorylated/activated Akt, mTOR, p70 S6K, and Erk1/2 levels compared to cells treated with serum taken pre-exercise. Our data suggest that post exercise serum has anti-cancer properties in lung cancer and deserves further systematic investigation in animal models.

A review of clinical effects associated with metabolic syndrome and exercise in prostate cancer patients

Androgen deprivation therapy (ADT), a primary treatment for locally advanced or metastatic prostate cancer, is associated with the adverse effects on numerous physiologic parameters, including alterations in cardiometabolic variables that overlap with components of the metabolic syndrome (MetS). As MetS is an established risk factor for cardiovascular mortality and treatment for prostate cancer has been associated with the development of MetS, interventions targeting cardiometabolic factors have been investigated in prostate cancer patients to attenuate the detrimental effects of ADT. Much support exists for exercise interventions in improving MetS variables in insulin-resistant adults, but less evidence is available in men with prostate cancer. Regular exercise, when performed at appropriate intensities and volumes, can elicit improvements in ADT-related adverse effects, including MetS, and contributes to the growing body of literature supporting the role of exercise in cancer survivorship. This review (1) discusses the biologic inter-relationship between prostate cancer, ADT and MetS, (2) evaluates the current literature in support of exercise in targeting MetS and (3) describes the physiological mechanisms by which exercise may favorably alter MetS risk factors in prostate cancer patients on ADT.

Relationship Between Aerobic Fitness, the Serum IGF-1 Profiles of Healthy Young Adult African American Males, and Growth of Prostate Cancer Cells

The growth of prostate tumors is mediated by the bioavailability of androgens and insulin-like growth factors. This study tested the hypothesis that healthy young adult African American men exhibiting low aerobic capacity (fitness) have serum insulin-like growth Factor-1 (IGF-1) and testosterone levels that promote growth of prostate cancer cells. A cross-sectional data research design was used to study groups of 18- to 26-year-old healthy men exhibiting low and moderate aerobic fitness, based on their peak oxygen consumption (VO_2peak). The individual serum levels of IGF-1, IGF-1 binding protein-3 (IGFBP-3), and testosterone were measured. In vitro growth of androgen-dependent LNCaP prostate tumor cells was measured after incubation in culture medium fortified with each subject's serum. Aerobic capacity was significantly greater in the moderate-fitness group than in the low-fitness group without an intergroup difference in body mass index. The serum IGF-1 concentration was significantly higher in the low-fitness group in the absence of an intergroup difference in serum testosterone. The serum IGFBP-3 concentration was significantly lower in the low-fitness group. Prostate tumor cell growth was significantly greater in the cultures incubated in media containing the sera of the low-fitness group than in the sera of the moderate-fitness group. These findings suggest that moderate aerobic fitness in young adults may decrease the circulating levels of free IGF-1 and lower the potential to support growth of prostate cancer cells.

Fat Intake Is Not Linked to Prostate Cancer: A Systematic Review and Dose-Response Meta-Analysis

Background

Since the late 1960s, the average global supply of fat has increased by 20 g per capita per day. While fat intake has been considered a potential risk factor for prostate cancer (Pca), the hypothesis from previous epidemiologic studies remained equivocal.

Materials and Methods

Relevant cohort studies were identified through a literature search in PubMed, ScienceDirect and Wiley Online Library up to March 1, 2015. A systematic review and dose-response meta-analysis were used to assess the relationship between fat intake and the risk for Pca.

Results

We identified 14 cohort studies, which included 37,349 cases and a total of 751,030 participants. We found no evidence of a non-linear association between fat intake and the risk for Pca. Overall, the summarized relative risks for every 28.35 g increment a day was 0.99 (95%CI: 0.98, 1.01; P=0.94; n=13) for total fat intake, 1.00 (95%CI: 1.00, 1.00; P=0.72; n=9) for saturated fat, 0.99 (95%CI: 0.95, 1.03; P=0.55; n=7) for polyunsaturated fat, and 1.00 (95%CI: 0.95, 1.04; P=0.85; n=8) for monounsaturated fat. Additionally, there was no link to the risk for advanced stage Pca regarding total fat intake (RR=1.02, 95%CI: 0.96, 1.08; P=0.63; n=5), saturated fat (RR=0.96, 95%CI: 0.84, 1.11; P=0.61; n=6), polyunsaturated fat (RR=0.96, 95%CI: 0.79, 1.17; P=0.68; n=6), or monounsaturated fat (RR=0.96, 95%CI: 0.86, 1.07; P=0.42; n=6). Subgroup and sensitively analyses showed consistent results.

Conclusion

Little evidence from published cohort studies supports the statement that total fat, saturated fat or unsaturated fat intake increases the risk for Pca or advanced stage Pca.

The impact of nutrition in urogenital cancers

Prostate, bladder and kidney cancers remain the most common cancers of the urinary tract. Despite improved primary prevention, detection and treatment, the incidence of age-related cancers of the urinary tract is likely to rise as a result of global population ageing. An association of diet with prostate, bladder and kidney carcinogenesis is plausible since the majority of metabolites, including carcinogens, are excreted through the urinary tract. Moreover, large regional differences in incidence rates of urologic tumours exist throughout the world. These rates change when people relocate to different geographic areas, which is suggestive of a strong environmental influence. As a result of these observations, numerous studies have been conducted to assess the effects of diet and nutritional status in kidney, bladder and prostate carcinogenesis. Here, we review the literature assessing the effect of diet and nutritional status on urological cancer risk, which has attracted the most interest.

Prediagnostic plasma IGFBP-1, IGF-1 and risk of prostate cancer

Insulin-like growth factor (IGF)-1 is associated with a higher risk of prostate cancer. IGF-binding protein (IGFBP)-1, a marker for insulin activity, also binds IGF-1 and inhibits its action. Data on IGFBP-1 and prostate cancer risk are sparse and whether the IGF and insulin axes interact to affect prostate cancer carcinogenesis is unknown. We evaluated the independent and joint influence of prediagnostic plasma levels of IGFBP-1 (fasting) and IGF-1 on risk of prostate cancer among 957 cases and 1,021 controls with fasting levels of IGFBP-1 and 1,709 cases and 1,778 controls with IGF-1 nested within the Health Professionals Follow-up Study. Unconditional logistic regression adjusting for matching factors was used to estimate the odds ratio (OR) and 95% confidence interval (CI). Higher prediagnostic fasting IGFBP-1 levels were associated with lower risk of prostate cancer (highest vs. lowest quartile OR = 0.67, 95% CI 0.52-0.86, p(trend) = 0.003), which remained similar after adjusting for IGF-1. Prediagnostic IGF-1 was associated with increased risk of prostate cancer (highest vs. lowest quartile OR = 1.28, 95% CI = 1.05-1.56, p(trend) = 0.01). The associations with each marker were primarily driven by lower-grade and non-advanced prostate cancer. Being low in IGFBP-1 and high in IGF-1 did not confer appreciable additional risk (p(interaction) = 0.42). In summary, prediagnostic fasting IGFBP-1 may influence prostate cancer carcinogenesis. Being low in IGFBP-1 or high in IGF-1 is sufficient to elevate the risk of prostate cancer.

Quality of Life and Sexual Health in the Aging of PCa Survivors

Prostate cancer (PCa) is the most common malignancy in elderly men. The progressive ageing of the world male population will further increase the need for tailored assessment and treatment of PCa patients. The determinant role of androgens and sexual hormones for PCa growth and progression has been established. However, several trials on androgens and PCa are recently focused on urinary continence, quality of life, and sexual function, suggesting a new point of view on the whole endocrinological aspect of PCa. During aging, metabolic syndrome, including diabetes, hypertension, dyslipidemia, and central obesity, can be associated with a chronic, low-grade inflammation of the prostate and with changes in the sex steroid pathways. These factors may affect both the carcinogenesis processes and treatment outcomes of PCa. Any treatment for PCa can have a long-lasting negative impact on quality of life and sexual health, which should be assessed by validated self-reported questionnaires. In particular, sexual health, urinary continence, and bowel function can be worsened after prostatectomy, radiotherapy, or hormone treatment, mostly in the elderly population. In the present review we summarized the current knowledge on the role of hormones, metabolic features, and primary treatments for PCa on the quality of life and sexual health of elderly Pca survivors.

Correlation of cancer incidence with diet, smoking and socio- economic position across 22 districts of Tehran in 2008

BACKGROUND

Variation in cancer incidence in geographical locations is due to different lifestyles and risk factors. Diet and socio-economic position (SEP) have been identified as important for the etiology of cancer but patterns are changing and inconsistent. The aim of this study was to investigate correlations of the incidence of common cancers with food groups, total energy, smoking, and SEP.

MATERIALS AND METHODS

In an ecological study, disaggregated cancer data through the National Cancer Registry in Iran (2008) and dietary intake, smoking habits and SEP obtained through a population based survey within the Urban Health Equity Assessment (Urban-HEART) project were correlated across 22 districts of Tehran.

RESULTS

Consumption of fruit, meat and dairy products adjusted for energy were positively correlated with bladder, colorectal, prostate and breast and total cancers in men and women, while these cancers were adversely correlated with bread and fat intake. Also prostate, breast, colorectal, bladder and ovarian cancers had a positive correlation with SEP; there was no correlation between SEP and skin cancer in both genders and stomach cancer in men.

CONCLUSIONS

The incidence of cancer was higher in some regions of Tehran which appeared to be mainly determined by SEP rather than dietary intake. Further individual data are required to investigate reasons of cancer clustering.

High concentrations of pyridoxal stimulate the expression of IGFBP1 in HepG2 cells through upregulation of the ERK/c‑Jun pathway

Increasing evidence suggests that dietary vitamin B6 is linked to the prevention of cancer and cardiovascular disease. However, the molecular mechanisms involved in this process are not yet understood. Preliminary results in the current study indicated, following DNA microarray analysis and quantitative PCR, that insulin‑like growth factor‑binding protein 1 (IGFBP1) mRNA is upregulated in HT29 colon carcinoma cells exposed to pyridoxal (PL, 500 µM). IGFBP1 is secreted from the liver and is hypothesized to exert a protective role in the development of cancer and cardiovascular disease. Thus, further experiments were performed to investigate the effect of PL on the expression of IGFBP1 in HepG2 hepatocellular carcinoma cells. The addition of PL (500 µM) markedly increased the expression of IGFBP1 mRNA in HepG2 cells at 6, 12 and 24 h (P<0.01), whereas other vitamers (500 µM), including pyridoxal 5'‑phosphate (PLP), pyridoxine (PN) and pyridoxamine (PM), caused no such effect. The expression of the IGFBP1 protein in the cell lysate and culture medium was elevated in the presence of PL. PL elevated expression of the active form of ERK1 protein, p‑ERK1, and the p‑c‑Jun protein, a downstream factor of ERK. Furthermore, IGFBP1 expression, elevated by PL, was suppressed by PD98059, an ERK inhibitor. Higher expression of IGFBP1 protein by PL was suppressed by cycloheximide. These results suggest that PL may induce the expression of IGFBP1 in hepatoma cells via a mechanism involving the ERK/c‑Jun pathway.

Effect of acute exercise on prostate cancer cell growth

Physical activity is associated with reduced risk of several cancers, including aggressive prostate cancer. The mechanisms mediating the effects are not yet understood; among the candidates are modifications of endogenous hormone levels. Long-term exercise is known to reduce serum levels of growth stimulating hormones. In contrast, the endocrine effects of acute endurance exercise include increased levels of mitogenic factors such as GH and IGF-1. It can be speculated that the elevation of serum growth factors may be detrimental to prostate cancer progression into malignancy. The incentive of the current study is to evaluate the effect of acute exercise serum on prostate cancer cell growth. We designed an exercise intervention where 10 male individuals performed 60 minutes of bicycle exercise at increasing intensity. Serum samples were obtained before (rest serum) and after completed exercise (exercise serum). The established prostate cancer cell line LNCaP was exposed to exercise or rest serum. Exercise serum from 9 out of 10 individuals had a growth inhibitory effect on LNCaP cells. Incubation with pooled exercise serum resulted in a 31% inhibition of LNCaP growth and pre-incubation before subcutaneous injection into SCID mice caused a delay in tumor formation. Serum analyses indicated two possible candidates for the effect; increased levels of IGFBP-1 and reduced levels of EGF. In conclusion, despite the fear of possible detrimental effects of acute exercise serum on tumor cell growth, we show that even the short-term effects seem to add to the overall beneficial influence of exercise on neoplasia.

Ligand-independent activation of MET through IGF-1/IGF-1R signaling

The receptor tyrosine kinase, MET, has been implicated in tumorigenesis and metastasis of many solid tumors, by multiple mechanisms, including cross talk with epidermal growth factor receptor. In this study, we examined the role of insulin-like growth factor receptor-1 (IGF-1R) signaling in MET activation, focusing on prostate cancer cells. Stimulation of the prostate cancer cell line PC3 with IGF-1 induces a delayed phosphorylation of MET at multiple sites (indicative of full activation), reaching a maximum 18 hr after IGF-1 addition. MET activation does not require the sole MET ligand hepatocyte growth factor (HGF), but does require transcription to occur. Furthermore, direct injection of IGF-1 is sufficient to induce MET activation in vivo, in a PC3 xenograft model. Pharmacologic or genetic inhibition of the tyrosine kinase, Src, abolishes MET phosphorylation, and expression of activated Src is sufficient to induce Met phosphorylation in the absence of IGF-1 stimulation. Activated MET is essential for IGF-1-mediated increased migration of PC3 cells, demonstrating an important biologic effect of IGF-1-mediated MET activation. Finally, we demonstrate that IGF-1-induced delayed MET activation occurs in multiple cell lines which express both the receptors, suggesting that IGF-1R-mediated MET activation may contribute to tumorigenic properties of multiple cancer types when both growth factor receptors are expressed. The results further suggest that MET may be activated by multiple receptor tyrosine kinase receptors, and dual targeting of these receptors may be important therapeutically.

Consumption of dairy and meat in relation to breast cancer risk in the Black Women's Health Study

PURPOSE

Dairy and meat consumption may impact breast cancer risk through modification of hormones (e.g., estrogen), through specific nutrients (e.g., vitamin D), or through products formed in processing/cooking (e.g., heterocyclic amines). Results relating meat and dairy intake to breast cancer risk have been conflicting. Thus, we examined the risk of breast cancer in relation to intake of dairy and meat in a large prospective cohort study.

METHODS

In the Black Women's Health Study, 1,268 incident breast cancer cases were identified among 52,062 women during 12 years of follow-up. Multivariable (MV) relative risks (RRs) and 95 % confidence intervals (CIs) were calculated using Cox proportional hazards models.

RESULTS

Null associations were observed for total milk (MV RR = 1.05, 95 % CI 0.74-1.46 comparing ≥1,000-0 g/week) and total meat (MV RR = 1.04, 95 % CI 0.85-1.28 comparing ≥1,000 < 400 g/week) intake and risk of breast cancer. Associations with intakes of specific types of dairy, specific types of meat, and dietary calcium and vitamin D were also null. The associations were not modified by reproductive (e.g., parity) or lifestyle factors (e.g., smoking). Associations with estrogen receptor (ER) positive (+), ER negative (-), progesterone receptor (PR) +, PR-, ER+/PR+, and ER-/PR- breast cancer were generally null.

CONCLUSIONS

This analysis of African-American women provides little support for associations of dairy and meat intake with breast cancer risk.

Patients with metabolic syndrome and widespread high grade prostatic intraepithelial neoplasia are at a higher risk factor of prostate cancer on re-biopsy: a prospective single cohort study

OBJECTIVES

To test the hypothesis that patients with widespread high grade prostatic intra epithelial neoplasia (wHGPIN) and metabolic syndrome (MetS) are at a higher risk of prostate cancer (PCa) at a repeat biopsy.

METHODS AND MATERIALS

We prospectively evaluated 161 patients submitted from December 2004 to December 2011 to prostate rebiopsy after a initial diagnosis of HGPIN in a tertiary academic center. A 12 core biopsy template was used for all the biopsies. Rebiopsy was performed six months after the initial biopsy independently from PSA level and the DRE finding. wHGPIN was defined as≥4 biopsy cores involved. MetS was defined according to the National Cholesterol Education Program's Adult Treatment Panel III criteria.

RESULTS

Overall, 64 patients (39.7%) presented wHGPIN and 97 isolated HGPIN (60.3%). MetS was found in 63 patients, 39.1% of the whole population. Out of them 16 (25.3%) and 47 (74.7%) patients had a diagnosis of isolated and wHGPIN (P = 0.001). PCa detection rate at repeat biopsy was significantly higher in patients with MetS and wHGPIN than in those with wHGPIN and no MetS (57.4% Vs 23.5%; P = 0.016). A logistic regression model confirmed that wHGPIN and MetS are independent risk factors of prostate cancer diagnosis (respectively: Odds ratio (OR) = 4.187, 95%CI: 1.65-10.57 p = 0.002 and OR=3.603, 95%CI: 1.41-9.19, p = 0.007).

CONCLUSION

Patients with MetS and wHGPIN are at a higher risk of PCa, therefore performing a new prostate biopsy in those patients should be recommended.

Combined Inhibition of IGF-1R/IR and Src family kinases enhances antitumor effects in prostate cancer by decreasing activated survival pathways

Background

Treatment of metastatic prostate cancer (PCa) with single agents has shown only modest efficacy. We hypothesized dual inhibition of different pathways in PCa results in improved tumor inhibition. The Src family kinases (SFK) and insulin-like growth factor-1 (IGF-1) signaling axes are aberrantly activated in both primary PCa and bone metastases and regulate distinct and overlapping functions in PCa progression. We examined the antitumor effects of combined inhibition of these pathways.

Materials and Methods

Src andIGF-1 receptor (IGF-1R) inhibition was achieved in vitro by short hairpin (sh)RNA and in vitro and in vivo by small molecule inhibitors (dasatinib and BMS-754807, against SFK and IGF-1R/Insulin Receptor(IR), respectively).

Results

In vitro, inhibition of IGF-1 signaling affected cell survival and proliferation. SFK blockade alone had modest effects on proliferation, but significantly enhanced the IGF-1R blockade. These findings correlated with a robust inhibition of IGF-1-induced Akt1 phophorylation by dasatinib, whereas Akt2 phosphorylation was SFK independent and only inhibited by BMS-754807. Thus, complete inhibition of both Akt genes, not seen by either drug alone, is likely a major mechanism for the decreased survival of PCa cells. Furthermore, dasatinib and BMS-754807 inhibited in vivo growth of the primary human xenograft MDA PCa 133, with corresponding inhibition of Akt in tumors. Also, both orthotopic and intratibial tumor growth of PC-3 cells were more potently inhibited by dual SFK and IGF-1R/IR blockade compared to either pathway alone, with a corresponding decrease in bone turnover markers.

Conclusions

Dual IGF-1R/IR and SFK inhibition may be a rational therapeutic approach in PCa by blocking both independent and complementary processes critical to tumor growth.

p53: exercise capacity and metabolism

PURPOSE OF REVIEW

There is an inverse relationship between cancer incidence and cardiorespiratory fitness in large population studies. Mechanistic insights into these observations may strengthen the rationale for encouraging exercise fitness in the clinics for cancer prevention and may promote the development of new preventive strategies.

RECENT FINDINGS

Studying the multifaceted activities of p53, a critical tumor suppressor gene, has revealed various cellular pathways necessary for adapting to environmental stresses. Genetic connections are being made between p53 and an increasing number of metabolic activities such as oxidative phosphorylation, glycolysis and fatty acid oxidation. In-vivo mouse models show that p53 plays an important role in determining both basal aerobic exercise capacity and its improvement by training.

SUMMARY

The genetic pathways by which p53 regulates metabolism and exercise may help explain significant epidemiologic observations connecting cardiorespiratory fitness and cancer. Further understanding of these molecular pathways through human translational studies may promote the development of new cancer preventive strategies.

Small-molecule protein tyrosine kinase inhibitors for the treatment of metastatic prostate cancer

The microenvironment is critical to the growth of prostate cancer (PCa) in the bone. Thus, for clinical efficacy, therapies must target tumor-microenvironment interactions. Several protein tyrosine kinases have been implicated in the development and growth of PCa bone metastasis. In this review, specific protein tyrosine kinases that regulate these complex interactions, including PDGFR, the EGFR family, c-Src, VEGFR, IGF-1R, FGFR and c-Met will be discussed, with an emphasis on why these kinases are promising therapeutic targets for metastatic PCa treatment. For each of these kinases, small-molecule inhibitors have reached clinical trials. Current results of these trials and future prospects for the use of tyrosine kinase inhibitors for the treatment of PCa bone metastases are also discussed.

mTORC1 activity as a determinant of cancer risk--rationalizing the cancer-preventive effects of adiponectin, metformin, rapamycin, and low-protein vegan diets

Increased plasma levels of adiponectin, metformin therapy of diabetes, rapamycin administration in transplant patients, and lifelong consumption of low-protein plant-based diets have all been linked to decreased risk for various cancers. These benefits may be mediated, at least in part, by down-regulated activity of the mTORC1 complex, a key regulator of protein translation. By boosting the effective availability of the translation initiator eIF4E, mTORC1 activity promotes the translation of a number of "weak" mRNAs that code for proteins, often up-regulated in cancer, that promote cellular proliferation, invasiveness, and angiogenesis, and that abet cancer promotion and chemoresistance by opposing apoptosis. Measures which inhibit eIF4E activity, either directly or indirectly, may have utility not only for cancer prevention, but also for the treatment of many cancers in which eIF4E drives malignancy. Since eIF4E is overexpressed in many cancers, strategies which target eIF4E directly--some of which are now being assessed clinically--may have the broadest efficacy in this regard. Many of the "weak" mRNAs coding for proteins that promote malignant behavior or chemoresistance are regulated transcriptionally by NF-kappaB and/or Stat3, which are active in a high proportion of cancers; thus, regimens concurrently targeting eIF4E, NF-kappaB, and Stat3 may suppress these proteins at both the transcriptional and translational levels, potentially achieving a very marked reduction in their expression.

Global Igfbp1 deletion does not affect prostate cancer development in a c-Myc transgenic mouse model

Circulating insulin-like growth factor binding protein 1 (IGFBP1) levels vary in response to nutritional status, and pre-clinical studies suggest that elevated IGFBP1 may be protective against the development and progression of prostate cancer. We hypothesized that global deletion of Igfbp1 would accelerate the development of prostate cancer in a c-Myc transgenic mouse model. To test our hypothesis, c-Myc transgenic mice (Myc/BP-1 wild-type (WT)) were crossed and interbred with the Igfbp1 knockout mice (Myc/BP-1 KO). The animals were placed on a high-protein diet at weaning, weighed every 2 weeks, and euthanized at 16 weeks of age. Prostate histopathology was assessed and proliferation status was determined by Ki-67 and proliferating cell nuclear antigen analyses. IGF-related serum biomarkers and body composition were measured. No significant difference in the incidence of prostate cancer was observed between the Myc/BP-1 KO and the Myc/BP-1 WT mice (65 and 80% respectively, P=0.48). Proliferation was significantly decreased by 71% in prostate tissue of Myc/BP-1 KO mice compared with Myc/BP-1 WT mice. Myc/BP-1 KO mice exhibited a significant 6.7% increase in body weight relative to the Myc/BP-1 WT mice that was attributed to an increase in fat mass. Fasting insulin levels were higher in the Myc/BP-1 KO mice without any difference between the groups in fasting glucose concentrations. Thus, contrary to our hypothesis, global deletion of Igfbp1 in a c-Myc transgenic mouse model did not accelerate the development of prostate cancer. Global Igfbp1 deletion did result in a significant increase in body weight and body fat mass. Further studies are required to understand the underlying mechanisms for these metabolic effects.

The correlation between metabolic syndrome and prostatic diseases

CONTEXT

Metabolic syndrome (MetS), a cluster of several metabolic abnormalities with a high socioeconomic cost, is considered a worldwide epidemic. Recent epidemiologic and clinical data suggest that MetS is involved in the pathogenesis and progression of prostatic diseases such as benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

OBJECTIVE

This review evaluates the available evidence of the role of MetS in BPH and PCa development and progression and discusses possible clinical implications for the management, prevention, and treatment of these diseases.

EVIDENCE ACQUISITION

A National Center for Biotechnology Information (NCBI) PubMed search for relevant articles published between 1995 and September 2011 was performed by combining the following Patient population, Intervention, Comparison, Outcome (PICO) terms: male, metabolic syndrome, prostate, benign prostatic hyperplasia, prostate cancer, prevention, diagnosis, treatment, and prognosis. Additional references were obtained from the reference list of full-text manuscripts.

EVIDENCE SYNTHESIS

MetS is a complex, highly prevalent disorder and a worldwide epidemic. Central obesity, insulin resistance, dyslipidemia, and hypertension are the main components of MetS. Notwithstanding all the attempts made to correctly define MetS, a major problem related to most definitions remains the applicability to different populations and ethnic groups. Although there is growing evidence of the association of MetS with the initiation and clinical progression of BPH and PCa, molecular mechanisms and effects on treatment efficacy remain unclear. Further research is required to better understand the role of MetS in BPH and PCa.

CONCLUSIONS

Data from the peer-reviewed literature suggest an association of MetS with BPH and PCa, although the evidence for a causal relationship remains missing. MetS should be considered a new domain in basic and clinical research in patients with prostatic disorders.

Tumor growth reduction in Walker 256 tumor-bearing rats performing anaerobic exercise: participation of Bcl-2, Bax, apoptosis, and peroxidation

Physical activity has been used in cancer prevention and treatment. In this study, we investigated some of the mechanisms by which anaerobic exercise reduces tumor growth. To do so, rats were trained for 8 weeks. Training consisted of jumping in a swimming pool for ten 30-s sets, with a load that was 50% of body weight attached to the back, 4 times per week. At the sixth week, anaerobic exercise trained rats (EX group) were inoculated with a suspension of Walker 256 tumor cells. Tumor weight, apoptotic tumor cells, tumor Bax and Bcl-2 protein expression, tumor lipid peroxidation, and tumor cell proliferation ex vivo were evaluated. Tumor weight was significantly lower in the EX group (∼30%) than in rats that did not undergo training (sedentary group) (p < 0.05). Apoptosis in the tumor cells of EX rats was 2-fold higher than in the tumor cells of sedentary rats; in addition, Bax expression increased by 10% and Bcl-2 decreased by 13% in EX rats. Lipid peroxidation was 4-fold higher in the tumor cells of EX rats than in those of sedentary rats (p < 0.05). Tumor cell proliferation ex vivo was 29% lower in the EX group than in the sedentary group (p < 0.05). In conclusion, Walker 256 tumor-bearing exercised rats presented more tumor cell apoptosis, a higher tumor content of lipid peroxides, pro-apoptotic protein expression balance, and reduced tumor weight and cell proliferation ex vivo, compared with sedentary rats. These events, together, account for the lower tumor growth we observed in the EX rats.

Reduced mitogenicity of sera following weight loss in premenopausal women

We investigated whether serum from normal weight women is less mitogenic and more apoptotic than sera from the same women in the overweight state. Sera from premenopausal women, age (mean ± SEE) 34.6 ± 0.53 years, who were randomized to caloric restriction (CR) (n = 13), CR + aerobic exercise (AE) (n = 14), or CR + resistance training (RT) (n = 20) were used to culture endometrial cancer cells. Phases of the cell cycle were determined, and proliferating cell nuclear antigen (PCNA) positivity was used to assess proliferation and apoptosis was assessed by determining cleaved caspase-3 and poly-ADP-ribose polymerase (PARP). Analyses showed that overall, cells grown in sera from the weight-reduced state had significantly more cells in G0/G1 and significantly fewer cells in the S and G2/M phases of the cell cycle than cells grown in sera from the overweight state. PCNA staining confirmed that cells grown in sera from the weight-reduced state had fewer proliferating cells. Cleaved caspase-3 and PARP were not different in cells grown in sera from the weight-reduced state compared to the overweight state. We conclude that weight loss with or without exercise could lower the risk for cancer through changes in serum that result in reduced cellular mitogenicity.

Growth hormone receptor deficiency is associated with a major reduction in pro-aging signaling, cancer, and diabetes in humans

Mutations in growth signaling pathways extend life span, as well as protect against age-dependent DNA damage in yeast and decrease insulin resistance and cancer in mice. To test their effect in humans, we monitored for 22 years Ecuadorian individuals who carry mutations in the growth hormone receptor (GHR) gene that lead to severe GHR and IGF-1 (insulin-like growth factor-1) deficiencies. We combined this information with surveys to identify the cause and age of death for individuals in this community who died before this period. The individuals with GHR deficiency exhibited only one nonlethal malignancy and no cases of diabetes, in contrast to a prevalence of 17% for cancer and 5% for diabetes in control subjects. A possible explanation for the very low incidence of cancer was suggested by in vitro studies: Serum from subjects with GHR deficiency reduced DNA breaks but increased apoptosis in human mammary epithelial cells treated with hydrogen peroxide. Serum from GHR-deficient subjects also caused reduced expression of RAS, PKA (protein kinase A), and TOR (target of rapamycin) and up-regulation of SOD2 (superoxide dismutase 2) in treated cells, changes that promote cellular protection and life-span extension in model organisms. We also observed reduced insulin concentrations (1.4 μU/ml versus 4.4 μU/ml in unaffected relatives) and a very low HOMA-IR (homeostatic model assessment-insulin resistance) index (0.34 versus 0.96 in unaffected relatives) in individuals with GHR deficiency, indicating higher insulin sensitivity, which could explain the absence of diabetes in these subjects. These results provide evidence for a role of evolutionarily conserved pathways in the control of aging and disease burden in humans.

Physical activity after diagnosis and risk of prostate cancer progression: data from the cancer of the prostate strategic urologic research endeavor

Vigorous activity after diagnosis was recently reported to be inversely associated with prostate cancer-specific mortality. However, men with metastatic disease may decrease their activity due to their disease; thus, a causal interpretation is uncertain. We therefore prospectively examined vigorous activity and brisk walking after diagnosis in relation to risk of prostate cancer progression, an outcome less susceptible to reverse causation, among 1,455 men diagnosed with clinically localized prostate cancer. Cox proportional hazards regression was used to examine vigorous activity, nonvigorous activity, walking duration, and walking pace after diagnosis and risk of prostate cancer progression. We observed 117 events (45 biochemical recurrences, 66 secondary treatments, 3 bone metastases, 3 prostate cancer deaths) during 2,750 person-years. Walking accounted for nearly half of all activity. Men who walked briskly for 3 h/wk or more had a 57% lower rate of progression than men who walked at an easy pace for less than 3 h/wk (HR = 0.43; 95% CI: 0.21-0.91; P = 0.03). Walking pace was associated with decreased risk of progression independent of duration (HR brisk vs. easy pace = 0.52; 95% CI: 0.29-0.91; P(trend) = 0.01). Few men engaged in vigorous activity, but there was a suggestive inverse association (HR ≥3 h/wk vs. none = 0.63; 95% CI: 0.32-1.23; P(trend) = 0.17). Walking duration and total nonvigorous activity were not associated with risk of progression independent of pace or vigorous activity, respectively. Brisk walking after diagnosis may inhibit or delay prostate cancer progression among men diagnosed with clinically localized prostate cancer.

Effect of low-intensity aerobic exercise on insulin-like growth factor-I and insulin-like growth factor-binding proteins in healthy men

Increased concentrations of circulating insulin-like growth factor-I (IGF-I) or IGF-I relative to IGF-binding proteins (IGFBPs) are associated with increased risk of developing several forms of cancer. Conversely, exercise is linked with reduced risk. This study aims to investigate the effect of a low-intensity exercise program on circulating levels of IGF-I, IGFBP-1, and IGFBP-3, in previously sedentary males. Fourteen healthy men participated in cycle ergometer training at lactate threshold intensity for 60 min/day, 5 days/week for 6 weeks. After aerobic training, insulin sensitivity improved by 20%, while fasting insulin levels decreased by 13%. Simultaneously, low-intensity aerobic training decreased the circulating levels of IGF-I by 9%, while IGFBP-1 levels increased by 16%. An interesting finding was that higher pretraining level of IGF-I was associated with greater decline in IGF-I with training. Insulin-sensitizing low-intensity aerobic exercise is thus considered to be an effective method for downregulating IGF-I and upregulating IGFBP-1 levels.

Diet, physical activity and energy balance and their impact on breast and prostate cancers

Obesity, physical activity status and circulating levels of sex steroid hormones and growth factor proteins are intrinsically linked to energy balance. Epidemiological studies have previously reported associations between these factors and the risk of hormone-related cancers such as prostate and breast cancer in men and postmenopausal women. An increasing number of intervention studies in 'at-risk' populations and cancer survivors are now investigating the effects of lifestyle interventions that promote negative energy balance on circulating levels of sex hormones and growth factor proteins as surrogate markers of cancer risk. Evidence from these studies suggests that lifestyle interventions can improve insulin sensitivity, alter the balance of circulating sex steroid hormones and insulin-like growth factor (IGF) axis proteins (including IGF-1 and the IGF binding proteins 1 and 3) and change the functioning of immune cells in peripheral blood. Such changes could influence the risk of developing hormone-related cancers, as well as having the potential to improve disease-free survival in patients recovering from cancer treatment. However, despite promising results, the methodological quality of most intervention studies has been limited due to small subject numbers, lack of adequate control groups or non-randomised designs and the absence of long-term follow-up measures. More intervention studies with randomised controlled designs, higher numbers of subjects and longer-term follow-up measures are needed to establish which combination of specific dietary and physical activity interventions work best for reducing risk in 'at-risk' populations and survivors, optimal dose-response relationships and the magnitude of change in surrogate markers of cancer risk that is required to induce a protective effect.

Reduced susceptibility to azoxymethane-induced aberrant crypt foci formation and colon cancer in growth hormone deficient rats

OBJECTIVES

To evaluate the role of GH in colon carcinogenesis, we examined the formation of aberrant crypt foci (ACFs) and tumor development in wild type (WT) and GH-deficient, spontaneous dwarf rats (SDRs) exposed to the carcinogen azoxymethane (AOM).

DESIGN

ACF were quantified by stereomicroscopy and tumor number and weights were recorded for each animal. Cell proliferation was measured by vincristine metaphase arrest, flow cytometry, and bromodeoxyuridine (BrdU) incorporation. Apoptosis was measured by TUNEL staining and cleaved caspase-3 immunohistochemistry. IGF-I was measured by radioimmunoassay (RIA). Hexokinase activity was measured by spectrophotometric assay. PARP cleavage, and IGF-IR, and p27(kip/cip) expression were measured by Western blotting.

RESULTS

ACFs detected by stereomicroscopy were markedly reduced ( approximately 85%) in SDRs vs. WT rats at 10, 25, and 28 weeks after AOM. Tumor incidence, number, and weight also were reduced in SDR vs. WT animals. AOM treatment increased cell proliferation in the distal colon (where tumors occur) of WT rats but not SDRs, and these changes corresponded to increased ACF and tumor formation. Apoptosis rates were similar in AOM-treated WT and SDRs. Alterations in serum IGF-I levels may contribute to differences in the proliferative response to AOM and decreased ACF formation in SDR vs. WT rats.

CONCLUSIONS

We conclude that early neoplastic lesions (ACFs) were reduced in GH-deficient animals. This effect corresponds with differences in AOM-induced proliferation, but not apoptosis. These data indicate that GH is required for the full effect of AOM on colon ACF and tumor development, and that the SDR rat is a promising model for studies regarding the role of GH/IGF system in the initiation and promotion of colon cancer.

Risk factors, prevention and early detection of prostate cancer

Approximately one in six men in the United States will develop prostate cancer during their lifetime. Genetic and environmental variables play a role in determining prostate cancer risk. This article highlights the latest evidence regarding the risk factors for prostate cancer. The current screening strategies using prostate-specific antigen and digital rectal examination are also discussed, as well as the limitations of these protocols and potential methods for improving early detection.