Possible roles of insulin, IGF-1 and IGFBPs in initiation and progression of colorectal cancer

Sugar sweetened beverages, natural fruit juices, and cancer: what we know and what still needs to be assessed

Cancer is known as one of the leading causes of death in the world. In addition to early mortality, cancer is associated with disability in affected patients. Among environmental risk factors, special attention has been paid to the role of dietary factors. In recent decades, the consumption of sugar-sweetened beverages (SSBs) and natural fruit juices has increased. Several studies have assessed the effects of these beverages on human health and found that a higher intake of SSBs is associated with a greater risk of obesity, diabetes, cardiovascular diseases, hypertension, and non-alcoholic fatty liver disease. However, current evidence for cancer incidence and mortality is not conclusive. In the current review, we concluded that SSBs intake might be positively associated with cancer incidence/mortality through their increasing effects on obesity, inflammatory biomarkers, serum levels of insulin-like growth factor-I (IGF-I), and advanced glycation end-products. Such a positive association was also seen for natural fruit juices. However, types of natural fruit juices were not considered in most previous studies. In addition, some types of cancer including brain, lung, and renal cancers were not assessed in relation to SSBs and natural fruit juices. Therefore, further studies are needed in this regard.

Mediterranean diet and olive oil, microbiota, and obesity-related cancers. From mechanisms to prevention

Olive oil (OO) is the main source of added fat in the Mediterranean diet (MD). It is a mix of bioactive compounds, including monounsaturated fatty acids, phytosterols, simple phenols, secoiridoids, flavonoids, and terpenoids. There is a growing body of evidence that MD and OO improve obesity-related factors. In addition, obesity has been associated with an increased risk for several cancers: endometrial, oesophageal adenocarcinoma, renal, pancreatic, hepatocellular, gastric cardia, meningioma, multiple myeloma, colorectal, postmenopausal breast, ovarian, gallbladder, and thyroid cancer. However, the epidemiological evidence linking MD and OO with these obesity-related cancers, and their potential mechanisms of action, especially those involving the gut microbiota, are not clearly described or understood. The goals of this review are 1) to update the current epidemiological knowledge on the associations between MD and OO consumption and obesity-related cancers, 2) to identify the gut microbiota mechanisms involved in obesity-related cancers, and 3) to report the effects of MD and OO on these mechanisms.

Targeted Delivery of PD-L1-Derived Phosphorylation-Mimicking Peptides by Engineered Biomimetic Nanovesicles to Enhance Osteosarcoma Treatment

Osteosarcoma is a rare malignant bone-originating tumor that usually occurs in young people. Programmed cell death 1 ligand 1 (PD-L1), an immune checkpoint protein, is highly expressed in osteosarcoma tissues. Several recent studies have indicated that the tumor-related role of PD-L1 in tumors, especially non-plasma membrane (NPM)-localized PD-L1, is not limited to immune regulation in osteosarcoma. Here, mass spectrometry analysis is combined with RNA-seq examination to identify the intracellular binding partners of PD-L1 and elucidate the underlying mechanism of its action. It is found that the NPM-localized PD-L1 interacted with Insulin-like growth factor binding protein-3 (IGFBP3) to promote osteosarcoma tumor growth by activating mTOR signaling. This interaction is enforced after phosphoglyceratekinase1 (PGK1)-mediated PD-L1 phosphorylation. Based on these findings, a phosphorylation-mimicking peptide is designed from PD-L1 and it is encapsulated with a Cyclic RGD (cRGD)-modified red blood cell membrane (RBCM) vesicle (Peptide@cRGD-M). The Peptide@cRGD-M precisely delivers the PD-L1-derived phosphorylation-mimicking peptide into osteosarcoma lesions and significantly promotes its therapeutic effect on the tumor. Therefore, this investigation not only highlights the function of NPM-localized PD-L1, but also uses an engineering approach to synthesize a small molecular peptide capable of inhibiting osteosarcoma growth.

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.

Growth Factors, PI3K/AKT/mTOR and MAPK Signaling Pathways in Colorectal Cancer Pathogenesis: Where Are We Now?

Colorectal cancer (CRC) is a predominant malignancy worldwide, being the fourth most common cause of mortality and morbidity. The CRC incidence in adolescents, young adults, and adult populations is increasing every year. In the pathogenesis of CRC, various factors are involved including diet, sedentary life, smoking, excessive alcohol consumption, obesity, gut microbiota, diabetes, and genetic mutations. The CRC tumor microenvironment (TME) involves the complex cooperation between tumoral cells with stroma, immune, and endothelial cells. Cytokines and several growth factors (GFs) will sustain CRC cell proliferation, survival, motility, and invasion. Epidermal growth factor receptor (EGFR), Insulin-like growth factor -1 receptor (IGF-1R), and Vascular Endothelial Growth Factor -A (VEGF-A) are overexpressed in various human cancers including CRC. The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) and all the three major subfamilies of the mitogen-activated protein kinase (MAPK) signaling pathways may be activated by GFs and will further play key roles in CRC development. The main aim of this review is to present the CRC incidence, risk factors, pathogenesis, and the impact of GFs during its development. Moreover, the article describes the relationship between EGF, IGF, VEGF, GFs inhibitors, PI3K/AKT/mTOR-MAPK signaling pathways, and CRC.

Cyclovirobuxine inhibits the progression of clear cell renal cell carcinoma by suppressing the IGFBP3-AKT/STAT3/MAPK-Snail signalling pathway

Of all pathological types of renal cell cancer (RCC), clear cell renal cell carcinoma (ccRCC) has the highest incidence. Cyclovirobuxine (CVB), a triterpenoid alkaloid isolated from Buxus microphylla, exhibits antitumour activity against gastric cancer and breast cancer; however, the mechanism by which CVB inhibits ccRCC remains unclear. The aim of our study was to explore the antitumour effects of CVB on ccRCC and to elucidate its exact mechanism. Cell viability, proliferation, cell cycle distribution, apoptosis, wound healing and invasion were evaluated. Furthermore, Western blotting, immunofluorescence staining, immunohistochemical staining, and bioinformatics analyses were utilized to comprehensively probe the molecular mechanisms. The in vivo curative effect of CVB was explored using a 786-O xenograft model established in nude mice. CVB reduced cell viability, proliferation, angiogenesis, the epithelial-mesenchymal transition (EMT), migration and invasion. In addition, CVB induced cell cycle arrest in S phase and promoted apoptosis. The expression of the EMT-related transcription factor Snail was significantly downregulated by CVB via the inhibition of the AKT, STAT3 and MAPK pathways. We revealed that insulin-like growth factor binding protein 3 (IGFBP3) was the true therapeutic target of CVB. CVB exerted anti-ccRCC effects by blocking the IGFBP3-AKT/STAT3/MAPK-Snail pathway. Targeted inhibition of IGFBP3 with CVB treatment may become a promising therapeutic regimen for ccRCC.

Insulin-Like Growth Factor 1 (IGF-1) Signaling in Glucose Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common aggressive carcinoma types worldwide, characterized by unfavorable curative effect and poor prognosis. Epidemiological data re-vealed that CRC risk is increased in patients with metabolic syndrome (MetS) and its serum components (e.g., hyperglycemia). High glycemic index diets, which chronically raise post-prandial blood glucose, may at least in part increase colon cancer risk via the insulin/insulin-like growth factor 1 (IGF-1) signaling pathway. However, the underlying mechanisms linking IGF-1 and MetS are still poorly understood. Hyperactivated glucose uptake and aerobic glycolysis (the Warburg effect) are considered as a one of six hallmarks of cancer, including CRC. However, the role of insulin/IGF-1 signaling during the acquisition of the Warburg metabolic phenotypes by CRC cells is still poorly understood. It most likely results from the interaction of multiple processes, directly or indirectly regulated by IGF-1, such as activation of PI3K/Akt/mTORC, and Raf/MAPK signaling pathways, activation of glucose transporters (e.g., GLUT1), activation of key glycolytic enzymes (e.g., LDHA, LDH5, HK II, and PFKFB3), aberrant expression of the oncogenes (e.g., MYC, and KRAS) and/or overexpression of signaling proteins (e.g., HIF-1, TGF-β1, PI3K, ERK, Akt, and mTOR). This review describes the role of IGF-1 in glucose metabolism in physiology and colorectal carcinogenesis, including the role of the insulin/IGF system in the Warburg effect. Furthermore, current therapeutic strategies aimed at repairing impaired glucose metabolism in CRC are indicated.

Involvement of IGF/IGFBP/Erk axis in the exercise-mediated preventive effects on colorectal cancer in rats

Recent studies have indicated that downregulation of insulin-like growth factor (IGF)-1 and its downstream targets are the main mechanisms underlying the anti-cancer impact of exercise. Therefore, we examined the impact of exercise on chemically induced-aberrant crypt foci (ACF), the earliest step of colorectal carcinogenesis, in rats and involvement of the IGF-1/IGF binding protein (IGFBP)-3/Erk axis. Twenty-four male Wistar rats were assigned into two groups (n=12): the control and exercise group. After eight weeks of training intervention, 6 rats were randomly selected from each group and received four injections of 1,2-dimethylhydrazine (DMH; 40 mg/kg), for two weeks. 0.2% methylene blue staining was used to evaluate the number of ACF in the colon. IGF-1 and IGFBP-3 protein levels in the serum were measured using commercially available ELISA kits for rat. The expression levels of proliferating cell nuclear antigen (PCNA), Erk1/2 and p-Erk1/2 were evaluated in colon tissue. Histological assessments were also performed in all groups. We found that the total number of ACF was significantly lowered after eight-week exercise (P<0.05). Moreover, the exercise program downregulated the IGF-1, PCNA, and p-Erk1/2 expressions and upregulated IGFBP-3 expression. Exercise was also found to increase the goblet cell number and improved colon architecture. Our finding demonstrated reduced ACF number in rat colons following exercise training, and this function may be associated with the inhibition of IGF-1/IGFBP-3/Erk1/2 signaling. Therefore, exercise appears to result in a lower number of ACF for preventing colon cancer.

Effect of Lycopene on Oral Squamous Cell Carcinoma Cell Growth by Inhibiting IGF1 Pathway

Purpose

Lycopene has produced robust clinical effects and shows a promising chemopreventive in the oral cancer and precancerous lesions. However, much is still unknown about its mechanisms of the carotenoid in protecting against oral squamous cell carcinoma (OSCC). Insulin-like growth factor 1 (IGF1) pathway serves as a key regulatory signal pathway in the tumor microenvironment, which may be associated with the angiogenesis, tumorigenicity, and cancer proliferation. The current study was focused on elucidating the potential pathway played for lycopene to exert its function in treating with OSCC.

Materials and Methods

Firstly, we explored the dose- and time-response of CAL-27 and WSU-HN6 cells to lycopene. Both cells were incubated with various concentrations of lycopene (0.25, 0.5, 1, 2 µM). The inhibiting rate of cell proliferation was assessed using MTT assay. To observe the regulating effect of lycopene on OSCC, cell migration, apoptosis and tumor formation were detected in vitro and in vivo. The potential signaling pathways of OSCC cells treated with lycopene were analyzed by Affymetrix microarrays. And then, we investigated the changing of IGF1 signaling pathway, on the protein levels of tumor tissue after lycopene.

Results

Cell proliferation was inhibited by lycopene in a dose- and time-dependent manner. The optimum inhibition efficiencies for OSCC cells were also found. Further, the results also demonstrated that pre-treatment of OSCC with lycopene drastically induced cell apoptosis suppresses cell migration and tumor growth. Mechanistically, ingenuity pathway analysis further revealed that IGF1 pathway participate in killing effects on OSCC after treatment of lycopene. Lycopene may inhibit the pathway by regulating protein expression of IGF1, IGF binding protein (BP) 1, IGFBP3, transcription factor Jun/AP-1 (JUN), and forkhead box O1 (FOXO1).

Conclusion

These observations indicate that lycopene regulates OSCC cell growth by inhibiting IGF1 pathway, which may be a promising agent for the treatment of OSCC.

Serum Levels of Insulin-like Growth Factor 1 and Insulin-like Growth Factor-binding Protein 2 as a Novel Biomarker in the Detection of Pancreatic Adenocarcinoma

BACKGROUND

Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor-binding protein 2 (IGFBP-2) are proteins that belong to the IGF axis, which is involved in glucose and lipid metabolism and may as well promote carcinogenesis.

GOALS

The aim of this study was to evaluate the serum concentration levels of IGF-1 and IGFBP-2 in patients with newly diagnosed pancreatic adenocarcinoma (PDAC) to verify their possible role in the diagnosis of the disease.

STUDY

The study included 69 patients with PDAC and 20 healthy controls. The concentrations of IGF-1 and IGFBP-2 were estimated by means of ELISA. The study protocol was approved by the Bioethics Committee at the Medical University of Lodz in Poland.

RESULTS

PDAC patients compared with controls have a significantly lower mean serum IGF-1 level (45.83±30.03 vs. 70.66±60.57 ng/mL; P<0.0001). In contrast, in PDAC patients, the mean IGFBP-2 level was significantly higher compared with the control group (225.06±86.37 vs. 51.92±29.40 ng/mL; P<0.0001). The results show that, at the 0.01 sensitivity level, the IGF-1/IGFBP-2 ratio <0.85 points indicates PDAC presence. At this level of sensitivity, the test has a specificity of 0.097 (α=0.01; β=0.097; IGF-1/IGFBP-2≤0.85).

CONCLUSIONS

Our results show that IGF-1 to IGFBP-2 ratio ≤0.85 may be a powerful PDAC indicator. Further studies in this area in a larger patient group are necessary to confirm our findings.

The Prognostic Significance of IGF-1R and the Predictive Risk Value of Circulating IGF-1 in Tunisian Patients with Laryngeal Carcinoma

The aim was to evaluate the clinical impact of IGF-1/IGF-1R in Tunisian laryngeal carcinoma. A high IGF-1R immunohistochemical expression was found in our series (81.43%). A tendency toward an association between IGF-1R expression and lymph node metastasis was found (p = 0.068). Patients with positive IGF-1R expression showed a short disease free survival (p = 0.053) and a high recurrence rate. Furthermore, circulating IGF-1 levels sera, detected by ELISA, were higher among patients compared to controls (p < 0.001). IGF-1R might have a prognostic significance and could be a factor of tumor recurrence. However, high levels of IGF-1 increase the risk of developing of LSCC disease.

Association between greater leg length and increased incidence of colorectal cancer: the atherosclerosis risk in communities (ARIC) study

PURPOSE

Previous studies have reported that taller people have an increased risk of colorectal cancer (CRC). We examined the association of two height components-leg length and sitting height-with CRC risk in 14,532 individuals aged 45-64 years in the Atherosclerosis Risk in Communities study.

METHODS

Anthropometrics were measured at baseline (1987-1989). Incident CRC cases (n = 382) were ascertained from 1987 to 2012. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios for CRC and colon cancer across quintiles of sex-specific leg length and sitting height.

RESULTS

The highest (versus the lowest) quintile of leg length was associated with a 36% greater CRC risk (p-trend = 0.04), and 51% greater colon cancer risk (p-trend = 0.01). For the top four quintiles combined, risk was increased by 34% for CRC and by 45% for colon cancer versus the lowest quintile. Total height and sitting height were not significantly associated with CRC or colon cancer risk. A small number of cases (n = 57) limited our ability to conduct subgroup analyses for rectal cancer.

CONCLUSIONS

A positive association of leg length with CRC and colon cancer risk suggests that biological mechanisms leading to greater leg length during puberty may explain the association between taller height and CRC.

Association Between Height and Clinical Outcome in Metastatic Colorectal Cancer Patients Enrolled Onto a Randomized Phase 3 Clinical Trial: Data From the FIRE-3 Study

BACKGROUND

Previous studies have found significant relationships between height and colorectal cancer (CRC) risk. Increased growth has been associated with activated pathways such as insulin-like growth factor 1. This study examined the impact of height on outcomes in metastatic CRC patients enrolled onto the FIRE-3 study, a randomized phase 3 clinical trial.

PATIENTS AND METHODS

A total of 695 patients with metastatic CRC were studied and height was measured in centimeters. Male patients were grouped as ≤ 165, 166-175, 176-185, and ≥ 186 cm in height; female patients were grouped as ≤ 154, 155-164, 165-174, and ≥ 175 cm in height. Primary end point was overall survival (OS); secondary end point was progression-free survival.

RESULTS

When patients' heights were categorized into 4 groups, the tallest group showed a worse OS compared to the shortest group; however, there was no linear relationship between height and OS. To investigate this, we showed the association between height as a continuous variable and OS. Patients shorter than 172 cm had a worse OS as their height decreased. Patients taller than 172 cm had a worse OS as their height increased. Moreover, patients with heights between 165 and 179 cm had a better OS compared to other patients (P = .05). This effect was independent of treatment arm and gender.

CONCLUSION

Patients shorter than 165 cm and taller than 179 cm have a worse OS, while those between 165 and 179 cm have a better OS. Hence, clinicians should consider height as an important prognostic factor when treating metastatic CRC patients. Future prospective studies are warranted to shed light on the mechanisms underlying the worse OS in taller patients.

Dose-response effects of exercise on insulin among colon cancer survivors

Physical activity is associated with a lower risk of disease recurrence among colon cancer survivors. The pathways through which physical activity may alter disease outcomes are unknown, but may include changes in metabolic growth factors, such as insulin. Between January 2015 and August 2015, 39 stage I-III colon cancer survivors were randomized to one of the three groups: usual care control, 150 min/week of aerobic exercise (low-dose) and 300 min/week of aerobic exercise (high-dose) for six months. The pre-specified key metabolic growth factor outcome was fasting insulin. Insulin resistance was quantified using the homeostatic model assessment. Mean age was 56.5 ± 10.0 years, 51% had stage III disease, 72% were treated with chemotherapy and the mean time since finishing treatment was 10.9 ± 6.1 months. Over six months, the low-dose group completed 141.5 ± 9.9 min/week of aerobic exercise, and the high-dose group completed 247.2 ± 10.7 min/week of aerobic exercise. Fasting insulin concentrations decreased 7.4 ± 9.4 pmol/L in the control group, 28.0 ± 8.3 pmol/L in the low-dose group and 20.7 ± 9.3 pmol/L in the high-dose group (nonlinear Ptrend = 0.042). Insulin resistance decreased 0.11 ± 0.20 in the control group, 0.63 ± 0.17 in the low-dose group and 0.43 ± 0.19 in the high-dose group (nonlinear Ptrend = 0.012). Aerobic exercise reduces insulin concentrations and insulin resistance among patients with stage I-III colon cancer. Prescribing 150 min/week of aerobic exercise may be sufficient for reducing insulin concentrations and insulin resistance, which may partially mediate the relationship between physical activity and colon cancer prognosis.

Metformin Use Is Associated with Reduced Incidence and Improved Survival of Endometrial Cancer: A Meta-Analysis

Studies have suggested that metformin can potentially decrease the incidence of cancer and improve survival outcomes. However, the association between metformin use and the incidence and survival of endometrial cancer (EC) remains controversial. So, a meta-analysis was performed. An electronic search was conducted using PubMed, EMBASE, and Web of Science. The outcome measures were relative risks (RRs) or hazard ratios (HRs) with 95% confidence intervals (CIs) comparing the EC incidence and survival in patients treated with and without metformin. Eleven studies involving 766,926 participants were included in this study. In the pooled analysis of five studies which evaluated the association of metformin use with the incidence of EC, we found that metformin use was associated with a 13% reduction in EC risk among patients with diabetes (RR = 0.87, 95% CI: 0.80–0.95; p = 0.006). In the pooled analysis of six retrospective cohort studies evaluating the effect of metformin on the survival of EC patients, we found that, relative to nonuse, metformin use significantly improved the survival of EC patients (HR = 0.63, 95% CI: 0.45–0.87; p = 0.006). This study showed that metformin use was significantly associated with a decreased incidence of EC in diabetes and a favorable survival outcome of EC patients.

Higher IGFBP-1 to IGF-1 serum ratio predicts unfavourable survival in patients with nasopharyngeal carcinoma

Background

The insulin-like growth factor (IGF) system plays an important role in the development and progression of cancer. However, little is known about the expression of the IGF system components and their clinicopathological significance and prognostic value in nasopharyngeal carcinoma (NPC).

Methods

IGF system components (IGF-1, IGF-2, IGF-1SR, IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4 and IGFBP-6) were quantified from the plasma of NPC patients and healthy individuals using the RayBio Human Cytokine Antibody Array. IGFBP-1 and IGF-1 mRNA levels were quantified by real-time qPCR, and protein expression was detected by western blot in nine NPC cell lines and four immortalized nasopharyngeal epithelial (NPE) cell lines. Tissue-specific expression of IGFBP-1 and IGF-1 was detected by immunohistochemistry in paraffin-embedded NPC tissues. ELISA analysis was used to measure the serum levels of IGFBP-1 and IGF-1 in 142 NPC patients and 128 healthy controls and determine potential correlation with clinicopathological parameters.

Results

Significantly higher levels of circulating IGFBP-1 and lower levels of IGF-1 and IGF-2 were detected in NPC patients compared to healthy controls by Cytokine Antibody Array analyses (P = 0.034, 0.012, 0.046, respectively). IGFBP-1 expression was detected in the majority of NPC cell lines, but not in NPE cell lines, and was shown to localize to the nucleus of tumour cells, in contrast to the cytoplasmic staining observed in normal cells. Importantly, IGFBP-1 expression was stronger in NPC tumour tissues compared to peritumoural tissues. In contrast, IGF-1 expression was weak or absent in NPC and NPE cell lines, with the exception of the EBV-infected C666 cell line, and was found to be expressed at lower levels in tumour tissues compared to tumour-adjacent normal tissue. Levels of serum IGFBP-1 were shown to be significantly higher in patients with NPCs compared to healthy control individuals (55.23 ± 41.25 μg/L vs. 32.08 ± 29.73 μg/L, P < 0.001), whereas serum levels of IGF-1 were significantly lower in NPC patients compared to healthy controls (98.14 ± 71.48 μg/L vs. 164.01 ± 92.08 μg/L, P = 0.001). Consistently, the IGFBP-1/IGF-1 serum ratio was shown to be significantly higher in NPC patients compared to healthy control individuals (P = 0.002). Serum levels of IGFBP-1 and the IGFBP-1/IGF-1 ratio significantly correlated with age (P = 0.020; P = 0.016), WHO histological classification (P = 0.044; P = 0.048), titre of EA (EB Virus Capsid Antigen-IgA) and NPC (P = 0.015; P = 0.016). In contrast, higher IGFBP-1 serum levels and IGFBP-1/IGF-1 ratio significantly correlated with poor RFS (P = 0.046; P = 0.037) and OS (P = 0.038; P = 0.009). Multivariate analysis revealed that the IGFBP-1/IGF-1 ratio, but not serum IGFBP-1 level, represents an independent risk factor for poor RFS (P = 0.044) and OS (P = 0.035).

Conclusions

A higher IGFBP-1/IGF-1 serum ratio is significantly associated with poor prognosis in NPC patients.

Insulin-like growth factor (IGF) axis in cancerogenesis

Determination of the role of insulin-like growth factor (IGF) family components in carcinogenesis of several human tumors is based on numerous epidemiological and pre-clinical studies, experiments in vivo and in vitro and on attempts at application of drugs affecting the IGF axis. Investigative hypotheses in original studies were based on biological functions manifested by the entire family of IGF (ligands, receptors, linking proteins, adaptor molecules). In the context of carcinogenesis the most important functions of IGF family involve intensification of proliferation and inhibition of cell apoptosis and effect on cell transformation through synthesis of several regulatory proteins. IGF axis controls survival and influences on metastases of cells. Interactions of IGF axis components may be of a direct or indirect nature. The direct effects are linked to activation of PI3K/Akt signaling pathway, in which the initiating role is first of all played by IGF-1 and IGF-1R. Activity of this signaling pathway leads to an increased mitogenesis, cell cycle progression, and protection against different apoptotic stresses. Indirect effects of the axis depend on interactions between IGF and other molecules important for cancer etiology (e.g. sex hormones, products of suppressor genes, viruses, and other GFs) and the style of life (nutrition, physical activity). From the clinical point of view, components of IGF system are first of all considered as diagnostic serous and/or tissue biomarkers of a given cancer, prognostic factors and attractive target of modern anti-tumor therapies. Several mechanisms in which IGF system components act in the process of carcinogenesis need to be clarified, mainly due to multifactorial etiology of the neoplasms. Pin-pointing of the role played in carcinogenesis by any single signaling pathway remains particularly difficult. The aim of this review is to summarize the current data of several epidemiological studies, experiments in vitro and on animal models, to increase our understanding of the complex role of IGF family components in the most common human cancers.

Molecular targets of metformin antitumor action

Epidemiological studies have shown that metformin, a first line therapeutic agent for diabetes mellitus, reduced the risk of developing various malignancies. Several preclinical studies established some possible mechanisms of its anticancer effects. The primary effect of metformin action is a decrease in cell energy status, which activates AMP-activated kinase (AMPK), a cellular metabolic sensor. This event is followed by a decrease in serum concentrations of insulin and insulin growth factor I (IGF-I), the potent mitogens for cancer cells. In addition to the indirect mode of action, metformin may exhibit direct inhibitory effect on cancer cells by targeting mammalian target of rapamycin (mTOR) signaling and anabolic processes. This review gathers information on mechanisms of metformin antitumor activity, with special attention given to the impact of this antidiabetic drug on insulin/PI3K/mTOR and AMPK signaling. Furthermore, the factors required for this novel activity of metformin are discussed.

A randomized phase II dose-response exercise trial among colon cancer survivors: Purpose, study design, methods, and recruitment results

BACKGROUND

Observational studies indicate that higher volumes of physical activity are associated with improved disease outcomes among colon cancer survivors. The aim of this report is to describe the purpose, study design, methods, and recruitment results of the courage trial, a National Cancer Institute (NCI) sponsored, phase II, randomized, dose-response exercise trial among colon cancer survivors.

METHODS/RESULTS

The primary objective of the courage trial is to quantify the feasibility, safety, and physiologic effects of low-dose (150 min·week(-1)) and high-dose (300 min·week(-1)) moderate-intensity aerobic exercise compared to usual-care control group over six months. The exercise groups are provided with in-home treadmills and heart rate monitors. Between January and July 2015, 1433 letters were mailed using a population-based state cancer registry; 126 colon cancer survivors inquired about participation, and 39 were randomized onto the study protocol. Age was associated with inquiry about study participation (P<0.001) and randomization onto the study protocol (P<0.001). No other demographic, clinical, or geographic characteristics were associated with study inquiry or randomization. The final trial participant was randomized in August 2015. Six month endpoint data collection was completed in February 2016.

DISCUSSION

The recruitment of colon cancer survivors into an exercise trial is feasible. The findings from this trial will inform key design aspects for future phase 2 and phase 3 randomized controlled trials to examine the efficacy of exercise to improve clinical outcomes among colon cancer survivors.

Clinical features of colorectal neoplasm patients with metabolic syndrome

AIM: To investigate the clinical features of colorectal neoplasm patients with metabolic syndrome (MS).

METHODS: A retrospective analysis was performed of clinical data for patients who were diagnosed with colorectal neoplasm with MS from May 2012 to May 2015.

RESULTS: A total of 107 patients were included. There were 72 males and 35 females, and their mean age was 66.84 years ± 10.58 years. There were 40 cases of adenomas and 67 cases of colorectal cancer. There was no significant difference (P > 0.05) in the rate of reduced high density lipoprotein-cholesterol (HDL-C) [29 (72.5%) vs 53(79.1%)] between patients with adenomas and those with colorectal cancer, but the rate of elevated triacylglycerol [14 (35.0%) vs 45 (67.2%)] differed significantly (P < 0.05). The rates of elevated CEA and CA199 showed no significant difference between patients with adenomas and colorectal cancer (P > 0.05); however, the rate of elevated CA125 and the rate of elevation of two or more of the three tumor markers were significantly higher in the colorectal cancer group than in the adenoma group (P < 0.05). In colorectal neoplasm patients with MS, 20 developed carcinoma metastases, and 16 cases died; the median survival time was 33 mo.

CONCLUSION: Colorectal neoplasm patients with metabolic syndrome are always diagnosed at old ages, and high level of TG may play a role in the evolution of colorectal adenomas to colorectal cancer. Joint detection of multiple tumor markers can be used to distinguish benign and malignant lesions in these patients.

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

Exercise and physical activity have been shown to reduce the risk of many common cancers and strongly influence tumor biology. A cause-effect mechanism explaining this relationship is dependent on cellular pathways that can influence tumor growth and are exercise responsive. The insulin-like growth factor (IGF) axis is reported to promote the development and progression of carcinomas through cellular signaling in cancerous tissues. This review summarizes the physiologic basis of the role of the IGF axis in oncology and the influence of exercise on this process. We examined the effects of exercise prescription on the IGF axis in cancer survivors by evaluating the current scope of the literature. The current research demonstrates a remarkable heterogeneity and inconsistency in the responses of the IGF axis to exercise in breast, prostate, and colorectal cancer survivors. Finally, this review presents an in-depth exploration of the physiologic basis and mechanistic underpinnings of the seemingly disparate relationship between exercise and the IGF axis in oncology. Although there is currently insufficient evidence to categorize the effects of exercise prescription on the IGF axis in cancer survivors, the inconsistency of results suggests a multifaceted relationship, the complexities of which are considered in this review.

Expression of insulin-like growth factor 1 in colorectal cancer: Relationship with angiogenesis

AIM: To investigate the relationship between the expression of insulin-like growth factor 1 (IGF-1) and clinicopathological parameters, as well as tumor angiogenesis in colorectal cancer.

METHODS: The expression of IGF-1 was detected using immunohistochemical method in 56 colorectal carcinoma and 20 normal colon tissues. Microvessel density (MVD) was counted by evaluating the expression of endothelial marker CD34.

RESULTS: The positive rates of IGF-1 in colorectal carcinoma and normal mucosa were 85.71% and 35%, respectively. The expression of IGF-1 correlated with lymph node metastasis significantly (P < 0.05). MVD values were 8.76±2.67 and 35.55 ± 7.78 in normal colon tissue and colorectal cancer, respectively. MVD correlated significantly with differentiation degree, invasion depth, Duke's stage and lymph node metastasis (P < 0.05 for all).

CONCLUSION: IGF-1 is highly expressed in colorectal adenocarcinoma and may be involved in the progression of colorectal cancer through enhancing tumor angiogenesis.

Understanding the Key to Targeting the IGF Axis in Cancer: A Biomarker Assessment

Type 1 insulin like growth factor receptor (IGF-1R) targeted therapies showed compelling pre-clinical evidence; however, to date, this has failed to translate into patient benefit in Phase 2/3 trials in unselected patients. This was further complicated by the toxicity, including hyperglycemia, which largely results from the overlap between IGF and insulin signaling systems and associated feedback mechanisms. This has halted the clinical development of inhibitors targeting IGF signaling, which has limited the availability of biopsy samples for correlative studies to understand biomarkers of response. Indeed, a major factor contributing to lack of clinical benefit of IGF targeting agents has been difficulty in identifying patients with tumors driven by IGF signaling due to the lack of predictive biomarkers. In this review, we will describe the IGF system, rationale for targeting IGF signaling, the potential liabilities of targeting strategies, and potential biomarkers that may improve success.

Genetic and dietary determinants of insulin-like growth factor (IGF)-1 and IGF binding protein (BP)-3 levels among Chinese women

Background

Higher insulin-like growth factor (IGF)-1 and lower IGF binding protein (BP)-3 levels have been associated with higher commoncancer risk, including breast cancer. Dietary factors, genetic polymorphisms, and the combination of both may influence circulating IGF-1 and IGFBP-3 serum concentrations.

Methods

From September 2011 to July 2012, we collected demographic, reproductive and dietary data on 143 women (≥40 years). We genotyped IGF-1 rs1520220 and IGFBP-3 rs2854744 and measured circulating IGF-1 and IGFBP-3 levels in serum. Covariance analyses were used to estimate the associations of serum levels of IGF-1 and IGFBP-3, and the molar ratio of IGF-1to IGFBP-3 with IGF-1 rs1520220 and IGFBP-3 rs2854744 genotypes. We subsequently assessed the combined influence of genetics and diet (daily intake of protein, fat and soy isoflavones) on IGF-1 and IGFBP-3 levels.

Results

Among women aged less than 50 years, circulating IGF-1 serum levels were significantly lower for those with CC genotype for IGF-1 rs1520220 than levels for those with the GC or GG genotypes (in recessive model: P = 0.007).In gene-diet analyses among these women, we found carrying CC genotype for IGF-1 rs1520220 and high soy isoflavone intake tend to be associated with lower circulating IGF-1 levels synthetically (P = 0.002). Women with GG or GC genotypes for IGF-1 rs1520220 and with low intake of soy isoflavones had the highest levels of circulating IGF-1 (geometric mean [95% CI]: 195 [37, 1021] µg/L). Comparatively, women with both the CC genotype and high soy intake had the lowest levels of circulating IGF-1 (geometric mean [95% CI]: 120 [38,378] µg/L).

Conclusions

IGF-1 serum levels are significantly lower among women with the CC genotype for IGF-1-rs1520220. High soy isoflavone intake may interact with carrying CC genotype for IGF-1-rs1520220 to lower women's serum IGF-1 levels more.

The risk of colonic adenomas and colonic cancer in obesity

Increasing body fatness has been associated with an increased burden from colorectal cancer. An increased susceptibility spanning the entire continuum from precancerous adenomatous polyps to the development of colorectal cancer, poor outcome with treatment, and reduced survival when compared to those with normal body weight has been described. It is unknown which age period and which degree and duration of excess weight are associated with increased colorectal cancer risk. It is uncertain whether weight loss can reverse this risk. If it can, how long will the new lower or normal weight be maintained to effect enduring risk reduction? Furthermore, it is controversial whether the increased burden of colorectal cancer warrants earlier and/or more frequent screening for obese persons. This article reviews the relationship between obesity and colorectal neoplasia, explores the postulated mechanism of carcinogenesis, discusses interventions to reduce the burden of disease, and suggests future directions of research.