Different forms and sources of iron in relation to colorectal cancer risk: a case-control study in China

Dietary intake of total, heme and non-heme iron and the risk of colorectal cancer in a European prospective cohort study

BACKGROUND

Iron is an essential micronutrient with differing intake patterns and metabolism between men and women. Epidemiologic evidence on the association of dietary iron and its heme and non-heme components with colorectal cancer (CRC) development is inconclusive.

METHODS

We examined baseline dietary questionnaire-assessed intakes of total, heme, and non-heme iron and CRC risk in the EPIC cohort. Sex-specific multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were computed using Cox regression. We modelled substitution of a 1 mg/day of heme iron intake with non-heme iron using the leave one-out method.

RESULTS

Of 450,105 participants (318,680 women) followed for 14.2 ± 4.0 years, 6162 (3511 women) developed CRC. In men, total iron intake was not associated with CRC risk (highest vs. lowest quintile, HRQ5vs.Q1:0.88; 95%CI:0.73, 1.06). An inverse association was observed for non-heme iron (HRQ5vs.Q1:0.80, 95%CI:0.67, 0.96) whereas heme iron showed a non-significant association (HRQ5vs.Q1:1.10; 95%CI:0.96, 1.27). In women, CRC risk was not associated with intakes of total (HRQ5vs.Q1:1.11, 95%CI:0.94, 1.31), heme (HRQ5vs.Q1:0.95; 95%CI:0.84, 1.07) or non-heme iron (HRQ5vs.Q1:1.03, 95%CI:0.88, 1.20). Substitution of heme with non-heme iron demonstrated lower CRC risk in men (HR:0.94; 95%CI: 0.89, 0.99).

CONCLUSIONS

Our findings suggest potential sex-specific CRC risk associations for higher iron consumption that may differ by dietary sources.

The role of oral iron in the treatment of adults with iron deficiency

Iron deficiency is the most common nutrient deficiency in the world, affecting over 20% of premenopausal women worldwide. Oral iron supplementation is often the first-line treatment for the acute and chronic management of iron deficiency due to its ease and accessibility. However, there is no consensus on the optimal formulation or dosing strategy, or which patients should be preferentially treated with intravenous iron. Management of iron deficiency is complicated by the hepcidin-ferroportin iron regulatory pathway, which has evolved to prevent iron overload and thereby creates an inherent limit on gastrointestinal iron uptake and efficacy of oral iron. Unabsorbed iron propagates many of the side effects that complicate oral iron use including dyspepsia and constipation, all of which can thus be exacerbated by excessive oral iron doses. Daily low dose and every other day dosing protocols have attempted to bypass this physiologic bottleneck to allow for effective absorption and limit side effects; however, this approach has still resulted in low fractional iron absorption. In the following manuscript, we review the pathophysiology of iron absorption and current evidence for various preparations of oral iron. Lastly, we highlight opportunities for further study to advance the care of individuals affected by iron deficiency.

The underexplored links between cancer and the internal body climate: Implications for cancer prevention and treatment

In order to effectively manage and cure cancer we should move beyond the general view of cancer as a random process of genetic alterations leading to uncontrolled cell proliferation or simply a predictable evolutionary process involving selection for traits that increase cell fitness. In our view, cancer is a systemic disease that involves multiple interactions not only among cells within tumors or between tumors and surrounding tissues but also with the entire organism and its internal "milieu". We define the internal body climate as an emergent property resulting from spatial and temporal interactions among internal components themselves and with the external environment. The body climate itself can either prevent, promote or support cancer initiation and progression (top-down effect; i.e., body climate-induced effects on cancer), as well as be perturbed by cancer (bottom-up effect; i.e., cancer-induced body climate changes) to further favor cancer progression and spread. This positive feedback loop can move the system towards a "cancerized" organism and ultimately results in its demise. In our view, cancer not only affects the entire system; it is a reflection of an imbalance of the entire system. This model provides an integrated framework to study all aspects of cancer as a systemic disease, and also highlights unexplored links that can be altered to both prevent body climate changes that favor cancer initiation, progression and dissemination as well as manipulate or restore the body internal climate to hinder the success of cancer inception, progression and metastasis or improve therapy outcomes. To do so, we need to (i) identify cancer-relevant factors that affect specific climate components, (ii) develop 'body climate biomarkers', (iii) define 'body climate scores', and (iv) develop strategies to prevent climate changes, stop or slow the changes, or even revert the changes (climate restoration).

Effect of extracts from eggs of Helix aspersa maxima and Helix aspersa aspersa snails on Caco-2 colon cancer cells

Background

Colorectal cancer is the third most commonly diagnosed cancer. Natural compounds, administered together with conventional chemotherapeutic agent(s) and/or radiotherapy, may be a novel element in the combination therapy of this cancer. Considering the anticancer properties of compounds derived from different tissues of various snail species confirmed earlier, the purpose of the present research was to evaluate the effect of extracts from eggs of Helix aspera maxima and Helix aspersa aspersa snails, and fractions of extracts containing particles of different molecular weights on Caco-2 human epithelial colorectal adenocarcinoma cells.

Methods

The extracts and fractions were analyzed for antioxidant activity, phenols and total carbohydrates using colorimetric methods. Lipid peroxidation products and glutathione in eggs were also examined using these methods. Crude protein and fat in eggs were determined. Molecular weights of egg proteins and glycoproteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Astaxanthin, selected vitamins and amino acids in eggs were measured using liquid chromatography methods, and minerals by emission spectroscopy, mass spectrometry or X-ray fluorescence. The action of extracts on the cell viability was determined by the MTT (methylthiazolyldiphenyl-tetrazolium bromide) test, based on the mitochondrial oxidative activity, after 24 and 72 h of treatment. The influence of fractions on the cell viability was assayed after 24 h. The effect of extracts on the percentage of live and dead cells was evaluated by the trypan blue assay, in which live cells exclude trypan blue, while dead cells take up this dye, after 12, 24, 48 and 72 h of treatment. Their influence on the integrity of cell membranes was determined based on the activity of LDH (lactate dehydrogenase), released from damaged cells, after 24 and 72 h of treatment. Then, the effect of extracts on the content of lipid peroxidation products in cells was examined using colorimetric method, after 24 h of treatment. Their influence on types of cell death was determined by flow cytometry, after this time.

Results

The extracts and their fractions containing molecules <3 kDa decreased the cell viability, after 24 h of treatment. The extracts reduced the percentage of live cells (also after 48 h), increased the degree of cell membrane damage and the amount of lipid peroxidation products, induced apoptosis and reduced necrosis.

Conclusions

Antioxidants, phenols, lipid peroxidation products, anticancer peptides, restriction of methionine, appropriate ratio of essential amino acids to non-essential amino acids, vitamin D₃, Ca, Mg, S, Cu, Mn, Zn, Se and other bioactive compounds comprised in the extracts and their additive and synergistic effects may have influenced Caco-2 cells. Natural extracts or the chemical compounds contained in them might be used in the combination therapy of colorectal cancer, which requires further research.

New Insights into Iron Deficiency Anemia in Children: A Practical Review

Iron deficiency anemia (IDA) is the most frequent hematological disorder in children, with an incidence in industrialized countries of 20.1% between 0 and 4 years of age and 5.9% between 5 and 14 years (39 and 48.1% in developing countries). Although IDA has been recognized for a long time, there are still uncovered issues and room for improving the management of this condition. New frontiers regarding its diagnosis and therapeutic options emerge every day; recently, innovative formulations of iron have been launched, both for oral and parenteral administration, with the aim of offering treatment schedules with higher efficacy and lower toxicity. As a matter of fact, glycinate and liposomal preparations, while maintaining a satisfying efficacy profile, have significantly fewer side effects, in comparison to the traditional elemental iron salts; parenteral iron, usually considered a second-choice therapy reserved to selected cases, may evolve further, as a consequence of the production of molecules with an interesting clinical profile such as ferrocarboxymaltose, which is already available for adolescents aged >14 years. The present article reports the clinically relevant latest insights regarding IDA in children and offers a practical guide to help pediatricians, particularly to choose the most appropriate prevention and therapy strategies.

Nrf2 Is a Potential Modulator for Orchestrating Iron Homeostasis and Redox Balance in Cancer Cells

Iron is an essential trace mineral element in almost all living cells and organisms. However, cellular iron metabolism pathways are disturbed in most cancer cell types. Cancer cells have a high demand of iron. To maintain rapid growth and proliferation, cancer cells absorb large amounts of iron by altering expression of iron metabolism related proteins. However, iron can catalyze the production of reactive oxygen species (ROS) through Fenton reaction. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an important player in the resistance to oxidative damage by inducing the transcription of antioxidant genes. Aberrant activation of Nrf2 is observed in most cancer cell types. It has been revealed that the over-activation of Nrf2 promotes cell proliferation, suppresses cell apoptosis, enhances the self-renewal capability of cancer stem cells, and even increases the chemoresistance and radioresistance of cancer cells. Recently, several genes involving cellular iron homeostasis are identified under the control of Nrf2. Since cancer cells require amounts of iron and Nrf2 plays pivotal roles in oxidative defense and iron metabolism, it is highly probable that Nrf2 is a potential modulator orchestrating iron homeostasis and redox balance in cancer cells. In this hypothesis, we summarize the recent findings of the role of iron and Nrf2 in cancer cells and demonstrate how Nrf2 balances the oxidative stress induced by iron through regulating antioxidant enzymes and iron metabolism. This hypothesis provides new insights into the role of Nrf2 in cancer progression. Since ferroptosis is dependent on lipid peroxide and iron accumulation, Nrf2 inhibition may dramatically increase sensitivity to ferroptosis. The combination of Nrf2 inhibitors with ferroptosis inducers may exert greater efficacy on cancer therapy.

DNAJC2 is reversely regulated by miR‑627‑3p, promoting the proliferation of colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies among human, which is often connected with increased incidence and mortality rate. DnaJ Heat Shock Protein Family (Hsp40) Member C2 (DNAJC2) is an epigenetic factor, which is involved in a number of cytological functions, such as transcriptional regulation and ubiquitination. A number of studies reveal that DNAJC2 is closely associated with several tumors. However, the function and mechanism of DNAJC2 in CRC remains to be elucidated. In the present study, the expression of DNAJC2 was detected in CRC tissues and adjacent normal tissues. The results indicated that DNAJC2 was increased in CRC tissues and the expression level of DNAJC2 was significantly associated with tumor size. Cell function was detected via Cell Counting Kit-8, 5-ethynyl-2′-deoxyuridine, colony formation assays and flow cytometry by upregulating or knocking down of DNAJC2. Overexpression of DNAJC2 could accelerate cell proliferation while suppression of DNAJC2 decreased cell proliferation, possibly via the regulation of cell cycle regulation in vitro. It was also found that the function of DNAJC2 was reversely regulated by miR-672-3p, causing the promoting of cell proliferation through the activation of AKT/P21 signal pathway in CRC cells. These results suggested that DNAJC2 is a tumor-regulated protein in the progression of CRC and may represent a novel target for CRC detection and therapy.

Interactions Between Vitamin D and Calcium Intake, Vitamin D Receptor Genetic Polymorphisms, and Colorectal Cancer Risk

BACKGROUND

Vitamin D has anticarcinogenic properties and acts through vitamin D receptor (VDR) to carry out its functions.

AIMS

This study explored the independent and combined effects of dietary vitamin D and calcium, and VDR genetic polymorphisms on colorectal cancer risk in a Chinese population.

METHODS

This ongoing case-control study recruited 488 cases with histologically confirmed colorectal cancer and 496 sex- and age-matched controls. Vitamin D and calcium intakes were assessed by a validated food frequency questionnaire, and VDR genotype was conducted for Fok I (rs2228570), Bsm I (rs1544410), Apa I (rs7975232), and Taq I (rs731236). Unconditional logistic regression was used to calculate odds ratio and 95% confidence interval after adjusting for various confounders.

RESULTS

No significant association was found between Fok I, Bsm I, Apa I, Taq I, and colorectal cancer risk. Higher intakes of dietary vitamin D and calcium were associated with 47% and 50% reduction in colorectal cancer risk. Significant interaction was observed between dietary vitamin D intake and Apa I polymorphisms in relation to colorectal cancer risk (P_interaction = 0.006). Subjects with higher dietary vitamin D intake and mutant Apa I A allele had a substantially decreased risk of colorectal cancer compared to Apa I aa carriers with lower vitamin D intake.

CONCLUSIONS

Our study supports that Apa I may interact with dietary vitamin D intake on colorectal cancer risk. However, no interactions were found between dietary vitamin D or calcium intakes and Fok I, Bsm I, and Taq I in relation to colorectal cancer risk.

Iron deficiency, immunology, and colorectal cancer

Excessive gut luminal iron contributes to the initiation and progression of colorectal cancer. However, emerging evidence suggests that reduced iron intake and low systemic iron levels are also associated with the pathogenesis of colorectal cancer. This is important because patients with colorectal cancer often present with iron deficiency. Iron is necessary for appropriate immunological functions; hence, iron deficiency may hinder cancer immunosurveillance and potentially modify the tumor immune microenvironment, both of which may assist cancer development. This is supported by studies showing that patients with colorectal cancer with iron deficiency have inferior outcomes and reduced response to therapy. Here, we provide an overview of the immunological consequences of iron deficiency and suggest ensuring adequate iron therapy to limit these outcomes.