Urinary Iodine Concentrations in Cancer Patients

Molecular Effects of Iodine-Biofortified Lettuce in Human Gastrointestinal Cancer Cells

Considering the growing number of cancer cases around the world, natural products from the diet that exhibit potential antitumor properties are of interest. Our previous research demonstrated that fortification with iodine compounds is an effective way to improve the antioxidant potential of lettuce. The purpose of the present study was to evaluate the effect of iodine-biofortified lettuce on antitumor properties in human gastrointestinal cancer cell lines, gastric AGS and colon HT-29. Our results showed that extracts from iodine-biofortified lettuce reduce the viability and proliferation of gastric and colon cancer cells. The extracts mediated cell cycle arrest which was accompanied by inactivation of anti-apoptotic Bcl-2 and activation of caspases, as assessed by flow cytometry. However, extracts from lettuce fortified with organic forms of iodine acted more effectively than extracts from control and KIO3-enriched plants. Using quantitative PCR, we detected the increase in pro-apoptotic genes BAD, BAX and BID in AGS cells whereas up-regulation of cell cycle progression inhibitor CDKN2A and downregulation of pro-proliferative MDM2 in HT-29 cells. Interestingly, lettuce extracts led to down-regulation of pro-survival AKT1 and protooncogenic MDM2, which was consistent for extracts of lettuce fortified with organic form of iodine, 5-ISA, in both cell lines. MDM2 downregulation in HT-29 colon cancer cells was associated with RB1 upregulation upon 5-ISA-fortified lettuce extracts, which provides a link to the epigenetic regulation of tumor suppressor genes by RB/MDM2 pathway. Indeed, SEMA3A tumor suppressor gene was hypomethylated and upregulated in HT-29 cells treated with 5-ISA-fortified lettuce. Control lettuce exerted similar effects on RB/MDM2 pathway and SEMA3A epigenetic activation in HT-29 cells. Our findings suggest that lettuce as well as lettuce fortified with organic form of iodine, 5-ISA, may exert epigenetic anti-cancer effects that can be cancer type-specific.

Fluoride Exposure Induces Inhibition of Sodium/Iodide Symporter (NIS) Contributing to Impaired Iodine Absorption and Iodine Deficiency: Molecular Mechanisms of Inhibition and Implications for Public Health

The sodium iodide symporter (NIS) is the plasma membrane glycoprotein that mediates active iodide transport in the thyroid and other tissues, such as the salivary, gastric mucosa, rectal mucosa, bronchial mucosa, placenta and mammary glands. In the thyroid, NIS mediates the uptake and accumulation of iodine and its activity is crucial for the development of the central nervous system and disease prevention. Since the discovery of NIS in 1996, research has further shown that NIS functionality and iodine transport is dependent on the activity of the sodium potassium activated adenosine 5'-triphosphatase pump (Na+, K+-ATPase). In this article, I review the molecular mechanisms by which F inhibits NIS expression and functionality which in turn contributes to impaired iodide absorption, diminished iodide-concentrating ability and iodine deficiency disorders. I discuss how NIS expression and activity is inhibited by thyroglobulin (Tg), tumour necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), interleukin 6 (IL-6) and Interleukin 1 beta (IL-1β), interferon-γ (IFN-γ), insulin like growth factor 1 (IGF-1) and phosphoinositide 3-kinase (PI3K) and how fluoride upregulates expression and activity of these biomarkers. I further describe the crucial role of prolactin and megalin in regulation of NIS expression and iodine homeostasis and the effect of fluoride in down regulating prolactin and megalin expression. Among many other issues, I discuss the potential conflict between public health policies such as water fluoridation and its contribution to iodine deficiency, neurodevelopmental and pathological disorders. Further studies are warranted to examine these associations.

Association between SULT1A1 Arg213His (rs9282861) Polymorphism and Risk of Breast Cancer: a Systematic Review and Meta-Analysis

Background: The Arg213His (rs9282861) polymorphism of Sulfotransferase Family 1A Member 1 (SULT1A1) gene has been reported to be associated with risk of breast cancer in some epidemiological studies. However, the results of these studies are conflicting and inconclusive. Therefore, this systematic review and meta-analysis was conducted to evaluate the association of SULT1A1 Arg213His (rs9282861) polymorphism with susceptibility to breast cancer.

Study design: A systematic review and meta-analysis.

Methods: A comprehensive literature search for eligible studies was conducted in PubMed, Elsevier, Science Direct, Scopus and Google Scholar databases up to October 5, 2017. Pooled odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) were used to evaluate the strength of the association using fixed effects models and random effects models.

Results: A total of 20 relevant case-control studies involving 11,077 cases and 14,798 controls were included in this meta-analysis. Overall, there was a significant association between the SULT1A1 Arg213His (rs9282861) polymorphism and risk of breast cancer in the allele mode (A vs. G: OR=1.117, 95% CI: 1.011, 1.233, P=0.029) and the homozygote model (AA vs. GG: OR=1.288, 95% CI: 1.036, 1.601, P=0.022). Subgroup analysis based on ethnicity suggested SULT1A1 Arg213His (rs9282861) polymorphism had a subtly increased breast cancer risk among Asian population, but not Caucasians. Further, subgroup analyses, significant associations were observed in hospital based group, RFLP-PCR group, and high quality studies subgroups.

Conclusions: This meta-analysis suggested that SULT1A1 Arg213His (rs9282861) polymorphism might be associated with breast cancer risk, especially among Asian population. Moreover, the SULT1A1 Arg213His polymorphism is of high clinical relevance by ethnicity and would be a useful marker to identify patients who are at higher risk for breast cancer.