Vitamin D in cancer chemoprevention

Context: There is increasing evidence that Vitamin D (Vit D) and its metabolites, besides their well-known calcium-related functions, may also exert antiproliferative, pro-differentiating, and immune modulatory effects on tumor cells in vitro and may also delay tumor growth in vivo. Objective: The aim of this review is to provide fresh insight into the most recent advances on the role of Vit D and its analogues as chemopreventive drugs in cancer therapy. Methods: A systematic review of experimental and clinical studies on Vit D and cancer was undertaken by using the major electronic health database including ISI Web of Science, Medline, PubMed, Scopus and Google Scholar. Results and conclusion: Experimental and clinical observations suggest that Vit D and its analogues may be effective in preventing the malignant transformation and/or the progression of various types of human tumors including breast cancer, prostate cancer, colorectal cancer, and some hematological malignances. These findings suggest the possibility of the clinical use of these molecules as novel potential chemopreventive and anticancer agent

The Effects of Retinol during In Vivo and In Vitro Oocyte Maturation and Embryonic Development.

Previous studies demonstrated that retinol administration to ewes, followed by natural service, resulted in embryos with improved competence to develop in vitro. In vivo studies with sheep and in vitro experiments with bovine embryos, were designed to evaluate the effects of retinol and to understand its mechanism(s) of action. The primary objective of the first experiment was to analyze ovine oocyte metabolism, and to assess the effects of retinol on this process. Sheep oocytes were matured in vitro over a 24 hour period in the presence of different radiolabeled substrates. Results revealed that oxidative metabolism measured by glutamine showed no significant differences over all time periods. Pyruvate oxidation was highest early in maturation and then decreased. Glycolysis was highest at the middle time period. Differences in metabolism between oocytes from retinol-treated ewes and those from control ewes were not detected. Next, varying concentrations of retinol were added either during in vitro maturation (IVM) or in vitro culture (IVC) of bovine oocyte and embryos, respectively. Our results demonstrated that 5mM retinol supplementation during IVM tended to improve embryonic development measured by the rate of blastocyst development. This concentration proved even more beneficial if the control blastocyst rate was below 20%. Furthermore, 10mM retinol appeared detrimental during IVC but not during IVM. In the third experiment, we evaluated the effects of 5mM retinol and 100mM cysteamine on bovine oocyte glutathione content. In addition, we investigated the combinatorial effects of retinol and cysteamine on in vitro bovine embryonic development. We did not observe an increase in glutathione levels in bovine oocytes treated with retinol. However, in the presence of cysteamine bovine oocytes exhibited an increase in glutathione content. Retinol and cysteamine treatment during IVM and IVC increased bovine blastocyst development, which may indicate that retinol is increasing the utilization or uptake of cysteine from the medium. Next, we evaluated the role of exogenous retinol supplementation to superovulated ewes on the glutathione content of mature oocytes collected from the oviducts. Our results did not reveal differences in glutathione content of oocytes from retinol-treated ewes versus those from control ewes. Antioxidant transcripts encoding for Mn-SOD, Cu-Zn SOD, GS, and GSTp, were detected in ovine oocytes matured in vivo. However, retinol did not appear to impact the expression levels of these transcripts

DAIDZEIN: A REVIEW OF PHARMACOLOGICAL EFFECTS

Background: Daidzein is an isoflavone with extensive nutritious value and is mainly extracted from soy plants. It is also called phytoestrogen due to its structural similarity to the human hormone estrogen. However, daidzein is distinct from estrogen due to the specificity of the estrogen receptor (ER) complex. In recent years, the pharmacological properties of daidzein have been extensively investigated and considerable progress has been made. The present review aims to evaluate the pharmacological effects and mechanisms of daidzein as reported in scientific literature. Materials and Methods: Studies were identified as reported in PubMed, Elsevier, Scholar, and Springer over the last ten years and this resulted in the identification of 112 papers. Results: Daidzein is reported to play a significant role in the prevention and treatment of a variety of diseases such as cancer, cardiovascular disease, diabetes, osteoporosis, skin disease, and neurodegenerative disease. This pharmacological activity is attributed to various metabolites including equol and trihydroxy isoflavone. Conclusion: Daidzein appears to play a significant role in the prevention of a variety of diseases and has the potential of being used in a clinical setting. However, further research is needed to understand its molecular mechanisms and safety for use in humans. Keywords: Plant, natural product, phytoestrogen, pharmacolog

Nutrition and Cancer

The development and treatment of cancer presents a complex interaction between tumor and host. Provision of nutrients not only enables the maintenance of nutritional status, but also provides substrates and signals for immunity, tumor metabolism and protection of the host from treatment toxicities. Fat is one dietary element that has been explored for its role in cancer development. While the bulk of these studies have been observational or experimental, the evidence assembled suggests that dietary lipids behave uniquely to prevent or promote cancers. An additional aspect of cancer development is the role of adipose tissue as a source of, and a responder to, inflammatory signals that may be involved in tumor development. This Special Issue of Nutrients focuses on fat and cancer. The contributors to this Special Issue are well-recognized leaders in the field of cancer and have unique areas of focus including metabolism, immunology, biochemistry, epidemiology and nutrition. Each contribution highlights the latest research in these areas and what is known about fat and cancer with topics ranging from diet and cancer prevention, mechanisms of n-3 fatty acids on tumor development and the role of adipose tissue in cancer development and progression