Acute iodine deficiency induces a transient VEGF-dependent microvascular response in mammary glands involving HIF-1, ROS, and mTOR

Fructose promotes angiogenesis by improving vascular endothelial cell function and upregulating VEGF expression in cancer cells

BACKGROUND

Fructose is a very common sugar found in natural foods, while current studies demonstrate that high fructose intake is significantly associated with increased risk of multiple cancers and more aggressive tumor behavior, but the relevant mechanisms are not fully understood.

METHODS

Tumor-grafting experiments and in vitro angiogenesis assays were conducted to detect the effect of fructose and the conditioned medium of fructose-cultured tumor cells on biological function of vascular endothelial cells (VECs) and angiogenesis. 448 colorectal cancer specimens were utilized to analyze the relationship between Glut5 expression levels in VECs and tumor cells and microvascular density (MVD).

RESULTS

We found that fructose can be metabolized by VECs and activate the Akt and Src signaling pathways, thereby enhancing the proliferation, migration, and tube-forming abilities of VECs and thereby promoting angiogenesis. Moreover, fructose can also improve the expression of vascular endothelial growth factor (VEGF) by upregulating the production of reactive oxygen species (ROS) in colorectal cancer cells, thus indirectly enhancing the biological function of VECs. Furthermore, this pro-angiogenic effect of fructose metabolism has also been well validated in clinical colorectal cancer tissues and mouse models. Fructose contributes to angiogenesis in mouse subcutaneous tumor grafts, and MVD is positively correlated with Glut5 expression levels of both endothelial cells and tumor cells of human colorectal cancer specimens.

CONCLUSIONS

These findings establish the direct role and mechanism by which fructose promotes tumor progression through increased angiogenesis, and provide reliable evidence for a better understanding of tumor metabolic reprogramming.

The Role of Iodine for Thyroid Function in Lactating Women and Infants

Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.

Impact of the phytochemicals cocktail "breast safeguard" in regulating the interplay between redox signalling and murine adenocarcinoma cell proliferation, survival and angiogenesis

Phytochemicals are natural plant extracts with a potent antioxidant, anti-inflammatory and anticancer characteristics by acting as a cell signalling modulator. This study aims to evaluate the effect of a commercial cocktail of phytochemicals "Breast safeguard" (BSG) in upregulating the expression of antioxidant enzymes to counteract signalling pathways that promote Ehrlich cells progression. The potent antioxidant activity and total phenolics and flavonoids contents of BSG was chemically validated, BSG treated mice showed a significant reduction at the tumor size, along with significant reduction in the expression of prognostic markers CEA and TNFα and induction of cell cycle arrest at G1/S phase as well as downregulation of Ki67. BSG supplementation significantly diminished H2O2, NO, MDA levels and upregulated the expression of SOD, CAT, GPx and GSH antioxidant enzymes in plasma and tumor tissues. BSG treatment markedly activated P53/Bax/Bcl2/c-caspase 3 signalling for cell apoptosis and attenuated the expression of antiapoptotic survivin protein. Meanwhile, BSG significantly diminished the expression of VEGF as an indication of angiogenesis inhibition. In conclusion, BSG exerted a significant upregulation of antioxidant enzymes which may be involved in upregulating P53/Bax/c-caspase 3 expression and attenuation of cell proliferation and angiogenesis.

Modulation of VEGF Expression and Oxidative Stress Response by Iodine Deficiency in Irradiated Cancerous and Non-Cancerous Breast Cells

Breast cancer remains a major concern and its physiopathology is influenced by iodine deficiency (ID) and radiation exposure. Since radiation and ID can separately induce oxidative stress (OS) and microvascular responses in breast, their combination could additively increase these responses. Therefore, ID was induced in MCF7 and MCF12A breast cell lines by medium change. Cells were then X-irradiated with doses of 0.05, 0.1, or 3 Gy. In MCF12A cells, both ID and radiation (0.1 and 3 Gy) increased OS and vascular endothelial growth factor (VEGF) expression, with an additive effect when the highest dose was combined with ID. However, in MCF7 cells no additive effect was observed. VEGF mRNA up-regulation was reactive oxygen species (ROS)-dependent, involving radiation-induced mitochondrial ROS. Results on total VEGF mRNA hold true for the pro-angiogenic isoform VEGF165 mRNA, but the treatments did not modulate the anti-angiogenic isoform VEGF165b. Radiation-induced antioxidant response was differentially regulated upon ID in both cell lines. Thus, radiation response is modulated according to iodine status and cell type and can lead to additive effects on ROS and VEGF. As these are often involved in cancer initiation and progression, we believe that iodine status should be taken into account in radiation prevention policies.