Dietary folate and related micronutrients, folate-metabolising genes, and ovarian cancer survival.

OBJECTIVE: Folate is essential for DNA synthesis and methylation and is implicated in tumour progression. Few studies have examined its role in ovarian cancer survival. Our objective was to determine relationships between intake of folate, related one-carbon nutrients, single nucleotide polymorphisms (SNPs) in folate-metabolising genes and survival following ovarian cancer diagnosis. METHODS: This analysis included 1270 women with invasive epithelial ovarian cancer diagnosed in 2002-2006. Pre-diagnostic and some post-diagnostic lifestyle, dietary, and sociodemographic information was collected via self-administered questionnaires. DNA samples were genotyped for SNPs in methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and methionine synthase reductase (MTRR) genes. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox regression. RESULTS: Multivariate analyses did not identify associations between higher pre-diagnostic intake of folate, folic acid, vitamins B2, B6, and B12, methionine, betaine or choline and survival overall. In stratified analyses, higher folic acid and folate intake was associated with significantly worse survival among women with mucinous tumours (HRs per 100 µg 1.30 and 1.43, respectively) and smokers (HRs per 100 µg 1.23 and 1.16 respectively). There was also a suggestion that higher supplemental folic acid use post-diagnosis was associated with worse survival (HR per 100 µg 1.03, 95%CI 1.00-1.05). MTHFR SNP rs2066470 was significantly associated with survival (per allele HR 0.81, 95%CI 0.67-0.98). CONCLUSIONS: Our data provide little evidence that folate intake affects ovarian cancer survival. However, combined effects with smoking, and findings within the mucinous subtype and for post-diagnosis folic acid, warrant further investigation.

Folate and related micronutrients, folate-metabolising genes and risk of ovarian cancer.

BACKGROUND/OBJECTIVE: Folates are essential for DNA synthesis and methylation, and thus may have a role in carcinogenesis. Limited evidence suggests folate-containing foods might protect against some cancers and may partially mitigate the increased risk of breast cancer associated with alcohol intake, but there is little information regarding ovarian cancer. Our aim was to evaluate the role of folate and related micronutrients, polymorphisms in key folate-metabolising genes and environmental factors in ovarian carcinogenesis. SUBJECTS/METHODS: Participants in the Australian Ovarian Cancer Study (1363 cases, 1414 controls) self-completed risk factor and food-frequency questionnaires. DNA samples (1638 cases, 1278 controls) were genotyped for 49 tag single-nucleotide polymorphisms (SNPs) in the methylene tetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and MTR reductase (MTRR) genes. Logistic regression models were used to generate adjusted odds ratios and 95% confidence intervals. RESULTS: We saw no overall association between the intake of folate, B vitamins or other methyl donors and ovarian cancer risk, although increasing folate from foods was associated with reduced risk among current smokers (P(trend)=0.03) and folic acid intake was associated with borderline significant increased risks among women who consumed ≥1 standard alcoholic drinks/day (odds ratio (OR)=1.64; 95% confidence interval (CI) 1.05-2.54, P(trend)=0.05). Two SNPs (rs7365052, rs7526063) showed borderline significant inverse associations with ovarian cancer risk; both had very low minor allele frequencies. There was little evidence for interaction between genotype and micronutrient intake or for variation between different histological subtypes of ovarian cancer. CONCLUSIONS: Our data provide little evidence to support a protective role for folate in ovarian carcinogenesis but suggest further evaluation of the joint effects of folic acid and alcohol is warranted.

Interpretation of iron studies in adolescent haemochromatosis.

We report the case of a 14-year-old girl who originally presented at the age of eight with a history of bloody stools, abdominal pain and weight loss. Initial iron studies showed raised serum iron and transferrin saturation but low ferritin and were interpreted as consistent with iron deficiency under treatment. As she had not taken any supplemental iron she later underwent genetic testing for the Cys282Tyr and His63Asp mutations of the HFE gene. On the basis of these results, she was diagnosed as having hereditary haemochromatosis (HH). This case highlights that a low serum ferritin does not exclude the diagnosis of HH and that the availability of genetic testing can now enable probands and affected family members to be identified.

Therapeutic potentiation of the immune system by costimulatory Schiff-base-forming drugs.

Immune responses are orchestrated by CD4 T lymphocytes, which receive a cognitive signal when clonally distributed receptors are occupied by major histocompatibility complex (MHC) class II-bound peptides on antigen-presenting cells (APCs). The APCs provide costimulatory signals, through macromolecules such as CD80, that regulate outcomes in terms of T-cell activation or anergy. We have studied essential complementary chemical events in the form of Schiff base formation between carbonyls and amines that are constitutively expressed on presenting cell and T-cell surfaces and provide a new target for manipulation of immune responses. Here we show that small Schiff base-forming molecules can substitute for the physiological donor of carbonyl groups and provide a costimulatory signal to CD4 Th-cells through a mechanism that activates clofilium-sensitive K+ and Na+ transport. One such molecule, tucaresol, enhances CD4 Th-cell responses, selectively favouring a Th1-type profile of cytokine production. In vivo tucaresol potently enhances CD4 Th-cell priming and CD8 cytotoxic T-cell priming to viral antigens, and has substantial therapeutic activity in murine models of disease.

Scanning X-ray microanalysis of microcarrier cultured endothelial cells: elemental changes during the transition to confluency and the effect of ionophore A23187.

Porcine endothelial cells were grown on microcarrier beads and examined by scanning electron microscopy (SEM) at various times after initiation of culture. Total cell coverage on the bead surface varied from mean values of approximately 7% (3h) to 80% (96h). Beam penetration into the subcellular matrix presents a major problem with SEM X-ray microanalysis of microcarrier cultured cells and necessitates the use of an accelerating voltage not exceeding 10kV. At this voltage and below, X-ray contribution from elements present in the microcarrier bead has minimal effect on the determination of cell elemental levels. Washing the cells with 0.15M sucrose was the least perturbing of the rinsing techniques investigated, removing surface culture medium but not internal diffusible ions. X-ray microanalysis revealed detectable levels of Na, P, S, Cl, K and Ca in the cells, with well-marked changes from initial attachment to confluency. The level of K decreased from approximately 1.0% at 3h to 0.4% at 24h, with a corresponding decrease in the K/Na ratio. This unexpectedly low level of K was invariably observed after 24h, and is a genuine feature of established microcarrier culture. The effect of ionophore A23187 was determined at the 3h culture stage, and resulted in significant increases in the concentration of divalent cations (Mg2+, Ca2+), monovalent ions (Na+, Cl-) and a decrease in the level of K+.