The Influence of Exercise on the Insulin-like Growth Factor Axis in Oncology: Physiological Basis, Current, and Future Perspectives

Exergaming Improves Cardiac Risk Factors in Prostate Cancer Patients: A Single-Blinded Randomized Controlled Trial

Purpose: Androgen deprivation therapy (ADT) may induce unfavorable changes in metabolic outcomes, insulin sensitivity, insulin-like growth factors (IGFs), and in serum levels of adipocyte-derived hormones. In this preplanned randomized ancillary study, we aimed to investigate the ability of exercise to counteract alterations in triglyceride, cholesterol, waist circumference, and insulin caused by ADT in men with locally advanced and metastatic prostate cancer (PCa). Materials and Methods: Forty-six PCa patients undergoing treatment were randomized to 12 weeks of 180 minutes of weekly unsupervised home-based exergaming or usual care. Blood glucose, lipids, cholesterol, adiponectin, leptin, insulin sensitivity, and the insulin growth factor axis were measured at baseline, and after 12 and 24 weeks. Biomarkers were analyzed using a linear mixed-effect model of the difference between the groups from baseline to week 24. In addition, blood pressure, body mass index, body weight, and waist circumference were measured at baseline and after 12 weeks/end of intervention and analyzed using adjusted linear regression analysis. Results: After 24 weeks, a significant difference was seen between the intervention and usual care groups in plasma triglyceride (diff: 0.5 mmol/L, P = 0.02) and high-density lipoprotein (HDL; diff: 0.2 mmol/L, P = 0.01) favoring the intervention group, whereas IGF-binding protein-3 (diff: 148 μg/L, P = 0.01) favored the usual care group. The remaining outcomes were unaffected. Conclusion: Improvement in HDL cholesterol could be used as a primary biomarker in future randomized controlled trials investigating the cardiovascular protecting properties of exergaming.

Exercise as a Promising Agent against Cancer: Evaluating Its Anti-Cancer Molecular Mechanisms

BACKGROUND

Cancer cases are continuously increasing, while the prevalence rates of physical inactivity are also continuously increasing. Physical inactivity is a causative factor in non-communicable diseases, including cancer. However, the potential beneficial effects of exercise on cancer treatment have not received much attention so far. The aim of this study was to highlight the relationship between cancer and exercise on a molecular basis.

METHODS

Comprehensive and in-depth research was conducted in the most accurate scientific databases by using relevant and effective keywords.

RESULTS

The mechanisms by which exercise may reduce cancer risk and/or progression may include the metabolic profile of hormones, systemic inflammation reduction, insulin sensitivity increase, antioxidant capacity augmentation, the boost to the immune system, and the direct effect on the tumor. There is currently substantial evidence that the effect of exercise may predict a stronger association with cancer and could supplementarily be embedded in cancer clinical practice to improve disease progression and prognosis.

CONCLUSION

The field of this study requires interconnecting the overall knowledge of exercise physiology with cancer biology and cancer clinical oncology to provide the basis for personalized targeting strategies that can be merged with training as a component of a holistic co-treatment approach to optimize cancer healthcare.

The role of exercise in obesity-related cancers: Current evidence and biological mechanisms

Cancer ranks among the five leading causes of death in almost all countries and has important repercussions for individual and public health, the healthcare system, and society in general. Obesity increases the incidence of many types of cancer, but growing evidence suggests that physical activity may decrease risk for developing a variety of obesity-related cancer types, and, in some cases, may improve cancer prognosis and mortality rates. This review summarizes recent evidence on the effect of physical activity on obesity-related cancer prevention and survival. For some cancers, including breast, colorectal, and endometrial cancer, there is strong evidence for a preventative effect of exercise, but for many others, including gallbladder and kidney cancer, and multiple myeloma, evidence is inconsistent or largely lacking. Though many potential mechanisms have been proposed to explain the onco-protective effect of exercise, including improved insulin sensitivity, alterations in sex hormone availability, improved immune function and inflammation, myokine secretion, and modulation of intracellular signaling at the level of AMP kinase, the exact mechanism(s) of action within each cancer subtype remains poorly defined. Overall, a deeper understanding of how exercise can help against cancer and of the exercise parameters that can be altered to optimize exercise prescription is necessary and should be the subject of future investigation.

Effects of exercise on inflammatory factors and IGF system in breast cancer survivors: a meta-analysis

BACKGROUND

At present, there are multiple hypotheses regarding the mechanisms underlying the effect of exercise on the postoperative inflammatory factors and the IGF system among breast cancer patients, especially. To determine the underlying mechanisms, prevent the recurrence of breast cancer and improve its prognosis, this paper will systematically evaluate the impact of exercise on inflammatory factors and the IGF system in breast cancer survivors.

METHODS

The PubMed, Embase, Web of Science, CNKI, Wanfang and VIP (Chinese scientific and technical journals) databases were systematically searched until April 2021. The search terms included 'exercise', 'inflammatory factor', 'IGF system' and 'breast cancer'. A total of 1066 relevant articles were retrieved. The articles were screened according to inclusion and exclusion criteria, such as study population, intervention method and type of experiment, and 11 articles were ultimately included. All statistical results were analysed using STATA 14.0 and Rstudio 4.1.1.

RESULTS

We found that exercise significantly reduced the level of IGF-1 (WMD, -19.947 ng/ml; 95% CI, -22.669 to -17.225; P = 0.000). Subgroup analysis showed that in the studies with an intervention period > 12 weeks, exercise significantly reduced IL-6 levels (WMD, -0.761 pg/ml; 95% CI, -1.369 to -0.153; p = 0.014), while in the studies with an intervention period ≤ 12 weeks, exercise significantly reduced CRP (WMD, -2.381 mg/L; 95% CI, -4.835 to 0.073, P = 0.001) and IL-10 levels (WMD, -7.141 pg/ml, 95% CI, -10.853 to -3.428; P = 0.000). In addition, aerobic exercise plus resistance training significantly reduced IL-6 levels (WMD, -1.474 pg/ml; 95% CI, -1.653 to -1.296; P = 0.000). The results of the sensitivity analysis showed that after excluding the studies with high heterogeneity, exercise significantly reduced the TNF-α levels in patients with breast cancer (WMD, -1.399 pg/ml; 95% CI, -1.718 to -1.080; P = 0.000).

CONCLUSION

Exercise reduces the postoperative levels of IGF-1, IL-6, CRP, IL-10 and TNF-α among patients with breast cancer, which may have a significant impact on inhibiting breast cancer recurrence and improving its prognosis. Future studies should examine the effects of different durations and types of exercise to develop individualized exercise prescriptions for breast cancer patients.

Linking Physical Activity to Breast Cancer Risk via Insulin/Insulin-Like Growth Factor Signaling System, Part 1: The Effect of Physical Activity on the Insulin/Insulin-Like Growth Factor Signaling System

Physical activity may reduce the risk of developing breast cancer via its effect on the insulin/insulin-like growth factor (IGF) signaling system. A systematic review searched for randomized controlled trials (RCT), Mendelian randomization and prospective cohort studies that examined the effects of physical activity on insulin/IGF signaling [IGFs, their binding proteins (IGFBP), and markers of insulin resistance] in adult women. Meta-analyses were performed to generate effect estimates. Risk of bias was assessed, and the Grading of Recommendations Assessment, Development, and Evaluation system used to determine the overall quality of the evidence. Fifty-eight RCTs met our inclusion criteria, no observational or Mendelian randomization studies met the criteria for inclusion. Meta-analyses indicated that physical activity interventions (vs. control) reduced fasting insulin, the Homeostatic Model Assessment for Insulin Resistance and fasting glucose. Physical activity increased IGF-1, but there was no clear effect on IGFBP-3 or the ratio of IGF-1:IGFBP-3. Strong evidence was only established for fasting insulin and insulin resistance. Further research is needed to examine the effect of physical activity on C-peptide and HBA1c in women. Reductions in fasting insulin and insulin resistance following exercise suggest some biological plausibility of the first part of the physical activity-insulin/IGF signaling-breast cancer pathway. See related article by Drummond et al., p. 2116.

The Insulin-like Growth Factor System and Colorectal Cancer

Insulin-like growth factors (IGFs) are peptides which exert mitogenic, endocrine and cytokine activities. Together with their receptors, binding proteins and associated molecules, they participate in numerous pathophysiological processes, including cancer development. Colorectal cancer (CRC) is a disease with high incidence and mortality rates worldwide, whose etiology usually represents a combination of the environmental and genetic factors. IGFs are most often increased in CRC, enabling excessive autocrine/paracrine stimulation of the cell growth. Overexpression or increased activation/accessibility of IGF receptors is a coinciding step which transmits IGF-related signals. A number of molecules and biochemical mechanisms exert modulatory effects shaping the final outcome of the IGF-stimulated processes, frequently leading to neoplastic transformation in the case of irreparable disbalance. The IGF system and related molecules and pathways which participate in the development of CRC are the focus of this review.

Does androgen deprivation impact associations between cognition and strength, fitness and function in community-dwelling men with prostate cancer? A cross-sectional study

OBJECTIVES

We investigated whether there were differences in associations between cognition with muscle strength, fitness and function in men with prostate cancer (PCa) treated with, and without androgen deprivation therapy (ADT) and non-PCa controls. A secondary aim was to compare differences in the prevalence of cognitive impairment.

DESIGN

This cross-sectional study compared 70 ADT-treated men with PCa aged 50-85 years to non-ADT-treated men (n=52) and non-PCa controls (n=70).

SETTING

University clinical exercise laboratory.

INTERVENTIONS

Nil.

PRIMARY AND SECONDARY OUTCOME MEASURES

Standardised assessments were conducted for cognition (learning, memory, attention, processing speed and executive function), muscle strength (grip strength and leg press), fitness (400 m walk), gait speed (4 m walk) and dual-tasking mobility (timed-up-and-go with a cognitive task).

RESULTS

ADT-treated men showed stronger associations between fitness and executive function and task switching relative to controls (both: p≤0.03). For both PCa groups (independent of ADT use), poorer dual-task mobility was more strongly associated with decreased psychomotor attention (both: p≤0.027) and global cognitive function (both: p≤0.031) compared with non-PCa controls. The overall prevalence of cognitive impairment was low (4%-13%) and did not differ between the groups.

CONCLUSIONS

The presence of PCa, with or without ADT treatment, did not increase the risk of cognitive impairment relative to non-PCa controls, yet did alter the associations between physical fitness and some measures of functional performance with certain cognitive domains. This highlights the importance of men with PCa maintaining fitness and functional capacity to optimise cognitive health.

TRIAL REGISTRATION NUMBER

This study was registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12614000317695).

Physical activity in relation to circulating hormone concentrations in 117,100 men in UK Biobank

PURPOSE

Physical activity may reduce the risk of some types of cancer in men. Biological mechanisms may involve changes in hormone concentrations; however, this relationship is not well established. Therefore, we aimed to investigate the associations of physical activity with circulating insulin-like growth factor-I (IGF-I), sex hormone-binding globulin (SHBG, which modifies sex hormone activity), and total and free testosterone concentrations, and the extent these associations might be mediated by body mass index (BMI).

METHODS

Circulating concentrations of these hormones and anthropometric measurements and self-reported physical activity data were available for 117,100 healthy male UK Biobank participants at recruitment. Objectively measured accelerometer physical activity levels were also collected on average 5.7 years after recruitment in 28,000 men. Geometric means of hormone concentrations were estimated using multivariable-adjusted analysis of variance, with and without adjustment for BMI.

RESULTS

The associations between physical activity and hormones were modest and similar for objectively measured (accelerometer) and self-reported physical activity. Compared to men with the lowest objectively measured physical activity, men with high physical activity levels had 14% and 8% higher concentrations of SHBG and total testosterone, respectively, and these differences were attenuated to 6% and 3% following adjustment for BMI.

CONCLUSION

Our results suggest that the associations of physical activity with the hormones investigated are, at most, modest; and following adjustment for BMI, the small associations with SHBG and total testosterone were largely attenuated. Therefore, it is unlikely that changes in these circulating hormones explain the associations of physical activity with risk of cancer either independently or via BMI.

Prevalence of Colorectal Polyps Based on Cardiorespiratory Fitness, Muscle Strength, Health Behavior, and Abdominal Obesity in Asymptomatic Elderly

Colorectal polyps are precursor lesions of colorectal cancer and are known to be associated with obesity, low physical activity, and unhealthy behavior. This cross-sectional study analyzed the prevalence of colorectal polyps based on cardiorespiratory fitness (CRF), muscle strength, and health behavior in older adults. Participants were asymptomatic and included 1024 men and 472 women aged 65-80 years who visited the health care center. Colonoscopy was performed under conscious sedation, and cardiorespiratory fitness was measured as the maximum oxygen uptake using gas analysis. Muscle strength was determined using isokinetic equipment, and physical activity, alcohol consumption, and smoking status were investigated using questionnaires. Waist circumference was measured at the thickest part of the middle of the abdomen. Logistic regression analysis was used to calculate the prevalence of colorectal polyps using odds ratios (ORs) based on the variables. The incidence of colorectal polyps was 65.2% in men and 48.5% in women. The ORs of colorectal polyps for obesity were 1.151 (95% confidence interval [CI], 1.010-2.291) and 1.178 (95% CI, 1.015-2.612) in men and women, respectively. The OR for colorectal polyps in male current smokers was 1.884. The ORs for low CRF were 1.985 and 1.841 in men and women, respectively, compared with high CRF. The prevalence of polyps increased with low muscle strength (men's OR 1.343 women's OR 1.440) and physical activity in both men (OR 1.693) and women (OR 1.861). In conclusion, lower CRF and muscle strength were associated with an increased prevalence of colorectal polyps in men and women. In both sexes, high waist circumference and low physical activity increased the prevalence of colorectal polyps.

High-intensity interval training or resistance training versus usual care in men with prostate cancer on active surveillance: A three-arm feasibility randomized controlled trial

BACKGROUND

This study assessed the feasibility of a phase II randomized controlled trial of high-intensity interval training (HIIT), resistance training (RT), and usual care (UC) in men with prostate cancer (PCa) on active surveillance (AS) and evaluated changes in clinically relevant outcomes.

METHODS

Eighteen men undergoing AS for PCa were randomized to HIIT (n=5), RT (n=7), or UC (n=6). Exercise participants attended two supervised sessions weekly and were instructed to complete one home-based session weekly for 8 weeks. UC participants were provided with physical activity guidelines.

RESULTS

Feasibility was met for attendance, compliance, and retention, but not recruitment. HIIT increased leg press (mean: +8.2kg, 95%CI 1.1, 15.3) from baseline to 8 weeks. RT increased seated row (mean: +11.7kg, 95%CI 6.1, 17.3) and chest press (mean: +10.4kg, 95%CI 5.3, 15.5), leg press (mean: +13.1kg, 95%CI 5.9, 20.3), serum insulin-like binding protein-3 (IGFBP-3) (mean: +400.0ng/ml, 95%CI 94.5, 705.5), and decreased interferon-γ (mean: -3.1pg/ml, 95%CI -5.7, -0.4). No changes were observed in the UC group.

CONCLUSION

HIIT and RT may be effective strategies for improving muscle strength; however, only RT may increase serum IGFBP-3. Strategies that can enhance recruitment in men on AS are important prior to conducting a phase II trial.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov number NCT04266262 Novelty bullets • High-intensity interval training or resistance training are feasible during active surveillance for prostate cancer. • Resistance training may suppress the tumor-promoting effects of insulin-like growth factor-I (IGF-I) via increased expression of IGFBP-3.

The Effects of Exogenous Lactate Administration on the IGF1/Akt/mTOR Pathway in Rat Skeletal Muscle

We investigated the effects of oral lactate administration on protein synthesis and degradation factors in rats over 2 h after intake. Seven-week-old male Sprague-Dawley rats were randomly divided into four groups (n = 8/group); their blood plasma levels of lactate, glucose, insulin, and insulin-like growth factor 1 (IGF1) were examined following sacrifice at 0, 30, 60, or 120 min after sodium lactate (2 g/kg) administration. We measured the mRNA expression levels of protein synthesis-related genes (IGF receptor, protein kinase B (Akt), mammalian target of rapamycin (mTOR)) or degradation-related genes (muscle RING-finger protein-1 (MuRF1), atrogin-1) and analyzed the protein expression and phosphorylation (activation) of Akt and mTOR. Post-administration, the plasma lactate concentration increased to 3.2 mmol/L after 60 min. Plasma glucose remained unchanged throughout, while insulin and IGF1 levels decreased after 30 min. The mRNA levels of IGF receptor and mTOR peaked after 60 min, and Akt expression was significantly upregulated from 30 to 120 min. However, MuRF1 and atrogin-1 expression levels were unaffected. Akt protein phosphorylation did not change significantly, whereas mTOR phosphorylation significantly increased after 30 min. Thus, lactate administration increased the mRNA and protein expression of protein-synthesis factors, suggesting that it can potentially promote skeletal muscle synthesis.

Body size and composition, physical activity and sedentary time in relation to endogenous hormones in premenopausal and postmenopausal women: Findings from the UK Biobank

Anthropometric and lifestyle factors may influence cancer risks through hormonal changes. We investigated cross-sectional associations between body size and composition, physical activity and sedentary time and serum concentrations of oestradiol (premenopausal women only), testosterone, sex hormone binding globulin (SHBG) and insulin-like growth factor-I (IGF-I) in 20 758 premenopausal and 71 101 postmenopausal women in UK Biobank. In premenopausal women, higher BMI (body mass index) was associated with a lower concentration of total oestradiol (15% difference in the highest vs lowest BMI group) and a higher concentration of calculated free oestradiol (22%). In both premenopausal and postmenopausal women, higher BMI was associated with higher concentrations of total and calculated free testosterone (premenopausal 29% and 113%, postmenopausal 39% and 126%, respectively) and lower concentrations of SHBG and IGF-I (premenopausal 51% and 14%, postmenopausal 51% and 12%, respectively). Similar associations were observed with waist to height ratio, waist to hip ratio and body or trunk fat mass. Self-reported physical activity was associated with somewhat lower concentrations of total and calculated free testosterone (premenopausal 10% difference [free testosterone], postmenopausal 5% and 11% difference respectively in the most vs least active group) and a higher concentration of SHBG (premenopausal 11%, postmenopausal 10%), and the opposite was true for self-reported sedentary time. The associations were slightly stronger with accelerometer-measured physical activity, but were attenuated after adjustment for BMI. Overall, our study confirms strong associations of hormones and SHBG with anthropometric factors. The associations with physical activity and sedentary time were at most modest.

Effects of a home-based exercise program on the insulin-like growth factor axis in patients operated for colorectal cancer in Sweden: Results from the randomised controlled trial PHYSSURG-C

OBJECTIVES

We report results from a subgroup within the ongoing PHYSSURG-C trial with the aim to examine effects of exercise on IGF-1 and IGFBP-3 in patients undergoing colorectal cancer surgery.

DESIGN

Randomised controlled trial.

SETTING

A Swedish university hospital.

PARTICIPANTS

Between 2015 and 2016, 217 patients were enrolled (I = 106, C = 111), with 122 patients that had given blood samples at baseline and at least at one follow-up (I = 51, C = 71). Patients 20 year or older with colorectal cancer were eligible. Exclusion criteria were emergency surgery, local surgery, language problems or inability to perform intervention.

INTERVENTIONS

Patients were computer-randomised to either a daily home-based aerobic exercise intervention (I), or to usual care (C). The intervention lasted two weeks before surgery and four weeks after discharge from hospital and consisted of medium-intensity aerobic exercise and inspiratory muscle training. Circulating concentrations of IGF-1 and IGFBP-3 were determined by blinded personnel at baseline, time of surgery and 4-6 weeks postoperatively.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcome of this subpopulation report was change in IGF-1/IGFBP-3 ratio, IGF-1 and IGFBP-3 concentrations from baseline to surgery, and 4-6 weeks postoperatively.

RESULTS

The IGF-1/IGFBP-3 ratio increased from baseline to surgery by 11% in I and 8% in C with no difference between groups (I vs. C: 1.04, 95%CI: 0.97-1.11; p = 1.000). Postoperative change was 5% in I and 3% in C with no difference between groups (I vs. C:1.03, 95%CI: 0.96-1.10; p = 1.000). Results concerning IGF-1 and IGFBP-3 also showed statistically significant dynamics over time with no difference between groups. No adverse events were reported.

CONCLUSIONS

The home-based exercise program in our trial did not have any effect on IGF-1, or IGFBP-3.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov with identifier NCT02299596. This work was funded externally.

The Adverse Effects of Androgen Deprivation Therapy in Prostate Cancer and the Benefits and Potential Anti-oncogenic Mechanisms of Progressive Resistance Training

Prostate cancer has the second highest incidence of all cancers amongst men worldwide. Androgen deprivation therapy (ADT) remains a common form of treatment. However, in reducing serum testosterone to castrate levels and rendering men hypogonadal, ADT contributes to a myriad of adverse effects which can affect prostate cancer prognosis. Physical activity is currently recommended as synergistic medicine in prostate cancer patients to alleviate the adverse effects of treatment. Progressive resistance training (PRT) is an anabolic exercise modality which may be of benefit in prostate cancer patients given its potency in maintaining and positively adapting skeletal muscle. However, currently, there is a scarcity of RCTs which have evaluated the use of isolated PRT in counteracting the adverse effects of prostate cancer treatment. Moreover, although physical activity in general has been found to reduce relapse rates and improve survival in prostate cancer, the precise anti-oncogenic effects of specific exercise modalities, including PRT, have not been fully established. Thus, the overall objective of this article is to provide a rationale for the in-depth investigation of PRT and its biological effects in men with prostate cancer on ADT. This will be achieved by (1) summarising the metabolic effects of ADT in patients with prostate cancer and its effect on prostate cancer progression and prognosis, (2) reviewing the existing evidence regarding the metabolic benefits of PRT in this cohort, (3) exploring the possible oncological pathways by which PRT can affect prostate cancer prognosis and progression and (4) outlining avenues for future research.

Impact of cancer rehabilitation on the prognosis of patients with hepatocellular carcinoma

Sarcopenia is a prognostic factor for patients with hepatocellular carcinoma (HCC). Cancer rehabilitation (CR) improves patients' physical function and muscle mass. We investigated the effects of CR on the prognosis of patients with HCC. The present study was a prospective observational study, which analyzed 152 patients with HCC who underwent transcatheter arterial chemoembolization (TACE) between 2013 and 2016. Patients were classified into the CR (n=85) and control (n=67) groups. The effects of CR on muscle mass were evaluated by changes in the skeletal muscle index (SMI) before and after TACE. Independent factors associated with survival were evaluated by Cox regression analysis. Kaplan-Meier analysis was used to compare the survival rate between the CR and control groups. The difference in survival rate between the two groups was also examined after propensity score matching. SMI was significantly increased in the CR group compared with the control group. In Cox regression analysis, independent factors associated with survival were CR and Child-Pugh class A (estimate 1.760, 95% CI 0.914–3.226, P=0.001; estimate 1.602, 95% CI 0.426–2.998, P=0.0129). The survival rate was significantly higher in the CR group than in the control group (median 552 vs. 424 days; P=0.0359). The survival rate was also significantly higher in the CR group than that in the control group after propensity score matching (median 529 vs. 369 days; P=0.0332). CR was associated with prolonged survival in patients with HCC who underwent TACE. Patients with cancer are recommended to maintain physical activity even during cancer treatment.

Aging and cancer: Is glucose a mediator between them?

Aging can increase cancer incidence because of accumulated mutations that initiate cancer and via compromised body control of premalignant lesions development into cancer. Relative contributions of these two factors are debated. Recent evidence suggests that the latter is rate limiting. In particular, hyperglycemia caused by compromised body control of blood glucose may be a factor of selection of somatic mutation-bearing cells for the ability to use glucose for proliferation. High glucose utilization in aerobic glycolysis is a long known characteristic of cancer. The new evidence adds to the concepts that have been being developed starting from mid-1970ies to suggest that age-related shifts in glucose and lipid metabolism increase the risk of cancer and compromise prognoses for cancer patients and to propose antidiabetic biguanides, including metformin, for cancer prevention and as an adjuvant means of cancer treatment aimed at the metabolic rehabilitation of patients. The new evidence is consistent with several effects of glucose contributing to aging and acting synergistically to enhance carcinogenesis. Glucose can affect (i) separate cells (via promoting somatic mutagenesis and epigenetic instability), (ii) cell populations (via being a factor of selection of phenotypic variants in cell populations for higher glucose consumption and, ultimately, for high aerobic glycolysis); (iii) cell microenvironment (via modification of extracellular matrix proteins), and (iv) the systemic levels (via shifting the endocrine regulation of metabolism toward increasing blood lipids and body fat, which compromise immunological surveillance and promote inflammation). Thus, maintenance of youthful metabolic characteristics must be important for cancer prevention and treatment.

Effect of exercise on colorectal cancer prevention and treatment

In recent years, because of improved cancer screening, detection and treatment modalities, a rapid increase in the population of colorectal and other cancer survivors has been observed. The increasing population has justified the requirement of preventive strategies such as lifestyle modifications with regard to obesity, physical activity, diet and smoking. Physical activity may prevent approximately 15% of the colon cancers. Furthermore, several observational studies have demonstrated the efficacy and dose-dependent and anti-cancer effects of exercise on decreasing the mortality and risk of recurrence before and after the colorectal cancer (CRC) diagnosis. However, the required exercise dose, type and intensity are yet unclear. The results of randomised prospective studies are expected to determine the optimal amount, type and intensity of exercise and formulate the most appropriate exercise plan and guidelines, according to the requirements and comorbidities of the patients. In addition, recent studies have focused on the molecular and genetic mechanisms underlying the effect of physical activity on disease outcomes and recurrence rates. This review aimed to investigate the effects of physical activity and the biological basis of these effects in preventing the risk and recurrence of CRC and decreasing the hazards of cancer and cancer treatment.

Targeting the IGF1R Pathway in Breast Cancer Using Antisense lncRNA-Mediated Promoter cis Competition

Aberrant insulin-like growth factor I receptor (IGF1R) signaling pathway serves as a well-established target for cancer drug therapy. The intragenic antisense long noncoding RNA (lncRNA) IRAIN, a putative tumor suppressor, is downregulated in breast cancer cells, while IGF1R is overexpressed, leading to an abnormal IGF1R/IRAIN ratio that promotes tumor growth. To precisely target this pathway, we developed an “antisense lncRNA-mediated intragenic cis competition” (ALIC) approach to therapeutically correct the elevated IGF1R/IRAIN bias in breast cancer cells. We used CRISPR-Cas9 gene editing to target the weak promoter of IRAIN antisense lncRNA and showed that in targeted clones, intragenic activation of the antisense lncRNA potently competed in cis with the promoter of the IGF1R sense mRNA. Notably, the normalization of IGF1R/IRAIN transcription inhibited the IGF1R signaling pathway in breast cancer cells, decreasing cell proliferation, tumor sphere formation, migration, and invasion. Using “nuclear RNA reverse transcription-associated trap” sequencing, we uncovered an IRAIN lncRNA-specific interactome containing gene targets involved in cell metastasis, signaling pathways, and cell immortalization. These data suggest that aberrantly upregulated IGF1R in breast cancer cells can be precisely targeted by cis transcription competition, thus providing a useful strategy to target disease genes in the development of novel precision medicine therapies.

Interaction between physical activity, PITX1 rs647161 genetic polymorphism and colorectal cancer risk in a Korean population: a case-control study

This study assessed the interaction between physical activity and colorectal cancer (CRC) risk based on a polymorphism in the paired-like homeodomain 1 (PITX1) gene in Koreans. In total, 923 cases and 1,846 controls were enrolled at the National Cancer Center, Korea. Subjects who did regular exercise showed a significantly reduced risk of CRC than those did not exercise regularly (OR = 0.37, 95% CI = 0.30-0.45). Subjects in the highest tertile of metabolic equivalents of task (MET)-minutes per week showed a significantly lower risk of CRC (OR = 0.62, 95% CI = 0.48-0.79, p-trend < 0.001). In the dominant model, minor allele carriers showed a significantly higher risk of CRC than subjects homozygous for the major allele (OR = 1.46, 95% CI = 1.18-1.80). The PITX1 genetic variant showed significant interactions with regular exercise and CRC risk (p-interaction = 0.018) and colon cancer risk (p-interaction = 0.029) among all subjects. Subjects who carried at least one minor allele and did not regularly exercise showed a greater risk of CRC (OR = 1.81, 95% CI = 1.37-2.41). Subjects who were homozygous for the major allele with high physical activity showed a significantly reduced risk of CRC (OR = 0.56, 95% CI = 0.38-0.82). Thus, individuals with PITX1 genetic variants can have benefit from physical activity regarding prevention of CRC risk in a Korean population.

The Effects of Resistance Exercise on Biomarkers of Breast Cancer Prognosis: A Pooled Analysis of Three Randomized Trials

Background: Using a secondary data analysis from randomized controlled trials comparing one year of resistance exercise (n = 109) to a placebo control condition (n = 106) in postmenopausal, posttreatment breast cancer survivors, we investigated the influence of resistance training and changes in body composition on markers associated with cancer progression.Methods: Measures included serum levels of insulin, IGF-1, IGFBP1-3, leptin, serum amyloid A (SAA), adiponectin, C-reactive protein (CRP), IL1β, TNFα, IL6, and IL8, and body composition (total, lean and fat mass in kg) by DXA at baseline, 6, and 12 months. Linear mixed effects models were used to examine the association between group, biomarkers, and body composition and whether or not changes in muscle strength or body composition influenced the effect of exercise on biomarkers.Results: CRP decreased over time among women participating in resistance training compared with increases in controls (P = 0.045). In stratified analyses and compared with increases in controls, women who gained strength reduced CRP (P = 0.003) and maintained levels of IL1β and IL6. Among exercisers who lost weight (≥2 kg), CRP (P = 0.045), leptin (P < 0.01), and SAA (P = 0.029) decreased, whereas IGF-BP1 (P = 0.036) increased compared with controls.Conclusions: Resistance training may lower inflammation and improve insulin pathway profiles, but the magnitude and degree of benefit from exercise may depend upon whether or not women gained strength, a possible marker of compliance with training, and/or lost weight during exercise.Impact: Future resistance training trials should consider these potential influencing factors as they may determine how well exercise can slow cancer progression and prevent disease recurrence. Cancer Epidemiol Biomarkers Prev; 27(2); 146-53. ©2017 AACR.