The Insulin-like Growth Factor System in Cancer Prevention: Potential of Dietary Intervention Strategies

FruHis significantly increases the anti-benign prostatic hyperplasia effect of lycopene: A double-blinded randomized controlled clinical trial

BACKGROUND

For decades, lycopene was considered the main compound of tomato protecting benign prostatic hyperplasia (BPH). Recent animal studies suggest that a newly discovered compound "FruHis" boosts lycopene for its action. This study aimed to determine whether FruHis enhances the action of lycopene to modify the laboratory parameters and clinical outcomes of patients with BPH.

MATERIALS AND METHODS

Current study was conducted on 52 BPH patients, who were randomly assigned into four groups of treatments: lycopene plus FruHis (n = 11, 25 mg/day lycopene and 10 mg/day FruHis), lycopene (n = 12, 25 mg/day lycopene), FruHis (n = 12, 10 mg/day FruHis), and placebo (n = 13). Patients received these supplements for 8 weeks.

RESULTS

FruHis intake strengthened the reducing effects of lycopene on insulin-like growth factor-1 (IGF-1) (-54.47 ± 28.36 ng/mL in the lycopene + FruHis group vs. -30.24 ± 46.69 ng/mL in the lycopene group), total prostate-specific antigen (TPSA) (-1.49 ± 4.78 ng/mL in the lycopene + FruHis group vs. -0.64 ± 2.02 ng/mL in the lycopene group), and symptom score (-4.45 ± 4.03 in the lycopene + FruHis group vs. -1.66 ± 5.41 in the lycopene group) in BPH patients. Such findings were also seen for body mass index (BMI) and waist circumference (WC). However, except for IGF-1, these reductions were not statistically significant compared with the placebo, and the intakes of lycopene and FruHis alone, however, were clinically important. Such effects of lycopene and FruHis were not seen for free PSA (FPSA) and FPSA/TPSA ratio.

CONCLUSION

Despite the non-significant effects of lycopene and FruHis, it seems that FruHis intake strengthens the beneficial effects of lycopene on IGF-1, TPSA, and symptom scores among BPH patients.

CLINICAL TRIAL REGISTRATION

[www.irct.ir], identifier [IRCT20190522043669N1].

Associations of serum carotenoid concentrations and fruit or vegetable consumption with serum insulin-like growth factor (IGF)-1 and IGF binding protein-3 concentrations in the Third National Health and Nutrition Examination Survey (NHANES III)

Dietary intervention may alter the insulin-like growth factor (IGF) system and thereby cancer risk. In a qualitative review, eleven of twenty studies showed a link between one or more carotenoids, vegetable or fruit intake and the IGF system, however, with partly contrary findings, such that no firm conclusion can be drawn. Therefore, we evaluated associations between serum carotenoid concentrations or the intake of fruits and vegetables with IGF-1, IGF binding protein (BP)-3 and their molar ratio (IGF-1:IGFBP-3) within the Third National Health and Nutrition Examination Survey (NHANES III, 1988–1994). In our analysis, we included 6061 NHANES III participants and used multivariable-adjusted linear regression models. IGF-1 concentrations were significantly positively associated with serum concentrations of lycopene, β-carotene, α-carotene, β-cryptoxanthin and lutein/zeaxanthin in men and women. Statistically significant positive associations were observed for serum concentrations of α-carotene and lutein/zeaxanthin and intake of fruits with serum IGFBP-3 concentrations in women, but not in men. The IGF-1:IGFBP-3 molar ratio was significantly positively associated with serum concentrations of lycopene, β-carotene and α-carotene in men and with β-carotene in women. In conclusion, dietary interventions with carotenoids, fruits and vegetables may affect the IGF system, although the direction of these effects is currently unclear.

Childhood dairy intake and adult cancer risk: 65-y follow-up of the Boyd Orr cohort

BACKGROUND

Dairy consumption affects biological pathways associated with carcinogenesis. Evidence for a link between cancer risk and dairy consumption in adulthood is increasing, but associations with childhood dairy consumption have not been studied adequately.

OBJECTIVE

We investigated whether dairy consumption in childhood is associated with cancer incidence and mortality in adulthood.

DESIGN

From 1937 through 1939, some 4,999 children living in England and Scotland participated in a study of family food consumption, assessed from 7-d household food inventories. The National Health Service central register was used to ascertain cancer registrations and deaths between 1948 and 2005 in the 4,383 traced cohort members. Per capita household intake estimates for dairy products and calcium were used as proxy for individual intake.

RESULTS

During the follow-up period, 770 cancer registrations or cancer deaths occurred. High childhood total dairy intake was associated with a near-tripling in the odds of colorectal cancer [multivariate odds ratio: 2.90 (95% CI: 1.26, 6.65); 2-sided P for trend = 0.005] compared with low intake, independent of meat, fruit, and vegetable intakes and socioeconomic indicators. Milk intake showed a similar association with colorectal cancer risk. High milk intake was weakly inversely associated with prostate cancer risk (P for trend = 0.11). Childhood dairy intake was not associated with breast and stomach cancer risk; a positive association with lung cancer risk was confounded by smoking behavior during adulthood.

CONCLUSIONS

A family diet rich in dairy products during childhood is associated with a greater risk of colorectal cancer in adulthood. Confirmation of possible underlying biological mechanisms is needed.

Lycopene supplementation elevates circulating insulin-like growth factor binding protein-1 and -2 concentrations in persons at greater risk of colorectal cancer

BACKGROUND

Higher circulating insulin-like growth factor I (IGF-I) concentrations have been related to a greater risk of cancer. Lycopene intake is inversely associated with cancer risk, and experimental studies have shown that it may affect the IGF system, possibly through an effect on IGF-binding proteins (IGFBPs).

OBJECTIVE

The objective of our study was to investigate the effect of an 8-wk supplementation with tomato-derived lycopene (30 mg/d) on serum concentrations of total IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3.

DESIGN

We conducted a randomized, placebo-controlled, double-blinded crossover study in 40 men and 31 postmenopausal women with a family history of colorectal cancer, a personal history of colorectal adenoma, or both.

RESULTS

Lycopene supplementation significantly (P = 0.01) increased serum IGFBP-1 concentrations in women (median relative difference between serum IGFBP-1 concentrations after lycopene supplementation and after placebo, 21.7%). Serum IGFBP-2 concentrations were higher in both men and women after lycopene supplementation than after placebo, but to a lesser extent (mean relative difference 8.2%; 95% CI: 0.7%, 15.6% in men and 7.8%; 95% CI: -5.0%, 20.6% in women). Total IGF-I, IGF-II, and IGFBP-3 concentrations were not significantly altered by lycopene supplementation.

CONCLUSIONS

This is the first study known to show that lycopene supplementation may increase circulating IGFBP-1 and IGFBP-2 concentrations. Because of high interindividual variations in IGFBP-1 and IGFBP-2 effects, these results should be confirmed in larger randomized intervention studies.

Isolated isoflavones do not affect the circulating insulin-like growth factor system in men at increased colorectal cancer risk

Epidemiological studies show that increased insulin-like growth factor (IGF)-I concentrations are related to increased colorectal cancer risk. A reduced colorectal cancer risk has been associated with isoflavones, which might affect the IGF-system because of their weak estrogenic activity. We conducted a randomized, placebo-controlled, double-blind crossover study to investigate the effect of an 8-wk isolated isoflavone supplementation (84 mg/d) on serum concentrations of total IGF-I, free IGF-I, total IGF-II, IGF binding protein (BP)-1, IGFBP-2, and IGFBP-3. Additionally, we investigated whether IGF-system component differences were related to concentrations of the more potent estrogenic isoflavone metabolite, equol. Our study population consisted of 37 men with a family history of colorectal cancer or a personal history of colorectal adenomas. Isoflavone supplementation did not significantly affect serum total IGF-I concentrations (relative difference between serum total IGF-I concentrations after isoflavone supplementation and after placebo: -1.3%, 95% CI -8.6 to 6.0%). Neither free IGF-I, nor total IGF-II, IGFBP-1, IGFBP-2, or IGFBP-3 concentrations were significantly altered. Interestingly, the change in serum IGF-I concentrations after isoflavone supplementation was negatively associated with serum equol concentrations (r=-0.49, P=0.002). In conclusion, isolated isoflavones did not affect the circulating IGF-system in a male high-risk population for colorectal cancer. However, to our knowledge, this is the first study that suggests isoflavones might have an IGF-I lowering effect in equol producers only. This underlines the importance of taking into account equol status in future isoflavone intervention studies.

Type I Insulin-like Growth Factor Receptor as a Therapeutic Target in Cancer: Figure 1

Data from experimental model systems and population studies have implicated type I insulin-like growth factor receptor (IGF1R) signaling in many different human cancers. Drugs to disrupt IGF1R function have been developed and are now entering clinical trial. This brief review will identify key areas to consider as these clinical trials move forward.