Synthetic and biological studies of phaeosphaerides.

The signal transducer and activator of transcription 3 (STAT3) has been validated as a suitable target for cancer therapy. Recent evidence by our group and others has shown that phaeosphaerides act as inhibitors of the STAT3 pathway. An efficient synthetic sequence to phaeosphaeride 1a has been previously disclosed. In this work, the first total synthesis of (±)-phaeosphaeride B (1d) and the unnatural phaeosphaeride 1b is reported. Additionally, the biological activities of 1a and 1b were investigated. (6S,7S,8S)-1a and (6R,7S,8S)-1b inhibited granulocyte colony-stimulating factor (GCSF)-stimulated phosphorylation of STAT1, STAT3, and STAT5 and IL-6-stimulated nuclear translocation of STAT3 alpha. In an SPR-based assay, (6S,7S,8S)-1a and (6R,7S,8S)-1b showed minimal ability to inhibit binding of STAT3 to its immobilized phosphotyrosylpeptide ligand (IC50 > 100 µM). Thus, (6S,7S,8S)-1a and (6R,7S,8S)-1b are likely upstream inhibitors of a kinase in the STAT signaling pathway and do not act through the inhibition of STAT3 dimerization by the blocking of the SH2 binding domain.

HBM4EU-MOM: Prenatal methylmercury-exposure control in five countries through suitable dietary advice for pregnancy - Study design and characteristics of participants.

BACKGROUND: Seafood is a major source of vital nutrients for optimal fetal growth, but at the same time is the main source of exposure to methylmercury (MeHg), an established neurodevelopmental toxicant. Pregnant women must be provided with dietary advice so as to include safely fish in their diet for nutrition and mercury control. The aim of this work is to present the design of a multicentre randomized control trial (RCT), which combines human biomonitoring (HBM) with dietary interventions using seafood consumption advice to pregnant women for MeHg control, and to collect information about other possible sources of exposure to mercury. It also presents the materials developed for the implementation of the study and the characteristics of the study participants, which were self-reported in the first trimester of pregnancy. METHODS: The "HBM4EU-MOM" RCT was performed in the frame of the European Human Biomonitoring Initiative (HBM4EU) in five coastal, high fish-consuming European countries (Cyprus, Greece, Spain, Portugal and Iceland). According to the study design, pregnant women (≥120/country, ≤20 weeks gestational age) provided a hair sample for total mercury assessment (THg) and personal information relevant to the study (e.g., lifestyle, pregnancy status, diet before and during the pregnancy, information on seafood and factors related to possible non-dietary exposures to mercury) during the first trimester of pregnancy. After sampling, participants were randomly assigned to "control" (habitual practices) or "intervention" (received the harmonized HBM4EU-MOM dietary advice for fish consumption during the pregnancy and were encouraged to follow it). Around child delivery, participants provided a second hair sample and completed another tailored questionnaire. RESULTS: A total of 654 women aged 18-45 years were recruited in 2021 in the five countries, primarily through their health-care providers. The pre-pregnancy BMI of the participants ranged from underweight to obese, but was on average within the healthy range. For 73% of the women, the pregnancy was planned. 26% of the women were active smokers before the pregnancy and 8% continued to smoke during the pregnancy, while 33% were passive smokers before pregnancy and 23% remained passively exposed during the pregnancy. 53% of the women self-reported making dietary changes for their pregnancy, with 74% of these women reporting making the changes upon learning of their pregnancy. Of the 43% who did not change their diet for the pregnancy, 74% reported that their diet was already balanced, 6% found it difficult to make changes and 2% were unsure of what changes to make. Seafood consumption did not change significantly before and during the first trimester of pregnancy (overall average ∼8 times per month), with the highest frequency reported in Portugal (≥15 times per month), followed by Spain (≥7 times per month). During the first-trimester of pregnancy, 89% of the Portuguese women, 85% of the Spanish women and <50% of Greek, Cypriot and Icelandic women reported that they had consumed big oily fish. Relevant to non-dietary exposure sources, most participants (>90%) were unaware of safe procedures for handling spillage from broken thermometers and energy-saving lamps, though >22% experienced such an incident (>1 year ago). 26% of the women had dental amalgams. ∼1% had amalgams placed and ∼2% had amalgams removed during peri-pregnancy. 28% had their hair dyed in the past 3 months and 40% had body tattoos. 8% engaged with gardening involving fertilizers/pesticides and 19% with hobbies involving paints/pigments/dyes. CONCLUSIONS: The study design materials were fit for the purposes of harmonization and quality-assurance. The harmonized information collected from pregnant women suggests that it is important to raise the awareness of women of reproductive age and pregnant women about how to safely include fish in their diet and to empower them to make proper decisions for nutrition and control of MeHg, as well as other chemical exposures.

Total synthesis and biological activity of the proposed structure of phaeosphaeride A.

The total synthesis of the structure assigned to the natural product phaeosphaeride A 1a was accomplished. The key steps involve the addition of vinyllithium reagent 7 to the acetonide-protected aldehyde 8 to access the carbon backbone of 1a, the introduction of the methoxylamino group followed by intramolecular hetero-Michael cyclization, and methanol elimination to form the dihydropyran ring. In this study, both enantiomers of 1a were synthesized and tested for biological activity. Preliminary results showed that (6R,7R,8R)-1a and (6S,7S,8S)-1a inhibit STAT3-dependent transcriptional activity in a dose-dependent manner and exhibit antiproliferative properties in breast (MDA-MB-231) and pancreatic (PANC-1) cancer cells.