Role of sphingolipids in oestrogen signalling in breast cancer cells: an update.

The signaling pathways activated by the steroid hormone oestrogen include a variety of cytoplasmic second messengers linked to a multitude of tissue-specific effects. In the last decade, sphingolipids and their membrane receptors were added to the list of oestrogen-activated mediators. Oestrogen triggers the sphingolipid signalling cascade in various tissues including breast cancer. Extensive research has shown that sphingolipids are the key regulatory molecules in growth factor networks. Sphingolipids can control the rate of cell proliferation and the differentiation outcome during malignant transformation. In this study, we summarise novel experimental evidences linking sphingolipids to oestrogen-activated effects, highlight the role of sphingolipids in cancer cells and discuss new avenues for future research at the intersection between oestrogen and sphingolipid signalling.

Estrogen defines the dynamics and destination of transactivated EGF receptor in breast cancer cells: role of S1P3 receptor and Cdc42.

Sphingosine-1-phosphate (S1P) receptors mediate transactivation of epidermal growth factor receptor (EGFR) by estrogen (E2). Here we report that the amount of intracellular EGFR remains elevated after stimulation of MCF-7 cells with E2 and S1P, although membrane-localized EGFR and S1P3 receptors are quickly internalized. Co-localization of internalized EGFR and LAMP-2 was lower in cells treated with E2/S1P, suggesting that endosomal EGFR might be directed for recycling instead of degradation. In addition, we found that E2/S1P activated Cdc42 and that knockdown of Cdc42 restores fast EGFR degradation after E2/S1P stimulation. Inhibition of S1P3 receptors prevented E2-induced activation of Cdc42, supporting the important role of the S1P receptor in E2 signaling. This is a novel mechanism further defining the effect of E2/S1P on the EGFR transactivation in breast cancer cells.

Randomized trial of a diabetes self-management education and family teamwork intervention in adolescents with Type 1 diabetes.

AIMS: To evaluate the effectiveness of a family-centred group education programme, in adolescents with Type 1 diabetes. METHODS: Three hundred and five adolescents with Type 1 diabetes; age 13.1 ± 1.9 years, diabetes duration 5.6 ± 3.3 years, BMI 20.9 ± 3.7 kg/m(2) , HbA(1c) 78 ± 6 mmol/mol (9.3 ± 1.9%) were randomly allocated to the Families and Adolescents Communication and Teamwork Study (FACTS) diabetes education programme; (six 90-min monthly sessions attended by parents and adolescents incorporating skills training and family teamwork) or conventional clinical care. Primary outcome was HbA(1c) at 18 months (12 months post-intervention). Secondary outcomes were HbA(1c) at 9 months, psychosocial outcomes, adolescent quality of life, well-being, family responsibility and insulin dose adjustment behaviours at 12 months (6 months post-intervention) and episodes of severe hypoglycaemia and diabetic ketoacidois during the 12 months post-intervention. All analyses are intention to treat. RESULTS: Session attendance was poor with 48/158 families (30.4%) not attending any sessions and only 75/158 (47.5%) families attending ≥ 4 group education sessions. All biomedical and psychosocial outcomes were comparable between groups. At 18 months there was no significant difference in HbA(1c) in either group and no between-group differences over time: intervention group 75 mmol/mol (9.0%) to 78 mmol/mol (9.3%), control group 77 mmol/mol (9.2%) to 80 mmol/mol (9.5%). Adolescents perceived no changes in parental input at 12 months. CONCLUSION: Poor attendance of group education sessions delivered in routine clinics was a major challenge. More personalized educational approaches may be required to support and motivate families who are struggling to integrate the demands of intensive insulin regimens into their daily lives.

Role of sphingolipids in the cytoplasmic signaling of estrogens.

Recent studies have clearly demonstrated that estrogen signaling is not limited by the canonical 'genomic' pathway. Estrogens have been shown to interact with multiple cytoplasmic signaling networks including that of growth factors, cytokines, and the most recently recognised participants, sphingolipids. Sphingosine kinase (SphK), a key enzyme in metabolic pathways of sphingolipids, plays an important role in cell signaling and regulates a wide range of biological functions, including the actions of estrogens. Herein we briefly review current experimental evidence showing a critical involvement of sphingolipids in estrogen signaling, especially in breast cancer and vascular endothelial cells. In the current review we mainly focus on the SphK pathway and discuss the potential role of SphK and sphingolipids in the cellular biology of estrogens.

Approaches to integrating paediatric diabetes care and structured education: experiences from the Families, Adolescents, and Children's Teamwork Study (FACTS).

AIMS: The Families, Adolescents and Children's Teamwork Study (FACTS) is a family-centred structured education programme for children and adolescents with Type 1 diabetes. It aims to integrate group-based diabetes education into routine care, enhance parental responsibility for self management and improve glycaemic control. METHODS: A randomized wait-list control group study allocated participants to either the immediate (four educational sessions during year 1) or delayed intervention (four educational sessions during year 2). In both groups, glycated haemoglobin (HbA1c) was measured 3-monthly and participants completed the Paediatric Quality of Life Inventory (PedsQL), Problem Areas in Diabetes Scale (PAID) and Diabetes Family Responsibility Questionnaire (DFRQ) before and after the intervention. RESULTS: Intention-to-treat analysis showed no significant difference in HbA1c or parental responsibility between participants randomized to the immediate or delayed programme. However, during 12 months' follow-up, families who attended > or = 2 sessions reported increased parental involvement (P = 0.01), and in children/adolescents who attended > or = 2 sessions HbA1c fell by 0.29% compared with an increase of 0.11% in non-attenders (P = 0.04). CONCLUSION: This family-centred education programme has been integrated into paediatric diabetes care with potential benefits on parental involvement and glycaemic control, but further study is warranted before routine application into clinical care.

A double-blind study comparing 0.5% and 1% tropicamide for annual retinal screening in diabetic adolescents.

AIMS: To determine whether there is any difference between 0.5% and 1% tropicamide in ocular discomfort and mydriatic efficacy in adolescents with Type 1 diabetes. METHODS: In a double-blind study, one drop of 0.5% tropicamide was instilled in one eye and one drop of 1% instilled in the other eye of 30 subjects aged 12-18 years. Drop strengths were randomized. Pupil size was measured before instillation, at 10, 20 and 30 min. Discomfort was measured using a recognized pain scale. RESULTS: Irrespective of the concentration of tropicamide used, all pupils dilated to at least 6 mm at 30 min, sufficient for successful ophthalmoscopy. Pain was significantly less when the lower concentration of tropicamide was used; pain score for the 0.5% group [median (interquartile range)] 1.0 (0-2) and 2.0 (1-3) for the 1.0% group, P = 0.009 (Wilcoxon rank test). CONCLUSIONS: This minor change in practice significantly reduces the distress associated with drop instillation without compromising the clinical examination, and may thus be important in encouraging compliance at the yearly diabetic review.

Translocation of protein tyrosine phosphatase Pez/PTPD2/PTP36 to the nucleus is associated with induction of cell proliferation.

Pez is a non-transmembrane tyrosine phosphatase with homology to the FERM (4.1, ezrin, radixin, moesin) family of proteins. The subcellular localisation of Pez in endothelial cells was found to be regulated by cell density and serum concentration. In confluent monolayers Pez was cytoplasmic, but in cells cultured at low density Pez was nuclear, suggesting that it is a nuclear protein in proliferating cells. This notion is supported by the loss of nuclear Pez when cells are serum-starved to induce quiescence, and the rapid return of Pez to the nucleus upon refeeding with serum to induce proliferation. Vascular endothelial cells normally exist as a quiescent confluent monolayer but become proliferative during angiogenesis or upon vascular injury. Using a 'wound' assay to mimic these events in vitro, Pez was found to be nuclear in the cells that had migrated and were proliferative at the 'wound' edge. TGFbeta, which inhibits cell proliferation but not migration, inhibited the translocation of Pez to the nucleus in the cells at the 'wound' edge, further strengthening the argument that Pez plays a role in the nucleus during cell proliferation. Together, the data presented indicate that Pez is a nuclear tyrosine phosphatase that may play a role in cell proliferation.

Stat6 activation is essential for interleukin-4 induction of P-selectin transcription in human umbilical vein endothelial cells.

Chronic upregulation of P-selectin expression on the surface of the endothelium has been observed in and likely contributes to a number of chronic inflammatory diseases, including atherosclerosis. Agonists of P-selectin expression fall into 2 categories: those that induce a very rapid, transient increase, lasting only hours, and those that induce prolonged upregulation lasting days. It is the latter group, which includes interleukin-4 (IL-4), that is likely to be a mediator of chronic P-selectin upregulation. The increase in P-selectin expression induced by IL-4 results from increased transcriptional activation of the P-selectin gene. The aim of this study was to deduce the postreceptor signaling pathway(s) giving rise to the prolonged increase in P-selectin expression induced by IL-4. We demonstrate the existence of 2 functional signal transducer and activator of transcription 6 (Stat6) binding sites on the P-selectin promoter and further demonstrate, by functional analysis of the P-selectin promoter, that binding of activated Stat6 to at least 1 site is essential for IL-4-induction of P-selectin transcription. Site 1 (nucleotide[nt] -142) bound Stat6 with a higher affinity than did site 2 (nt -229), and this difference was reflected functionally as constructs in which only site 1 was functional showed full IL-4 inducibility, whereas constructs in which only site 2 was functional showed only 40% of maximal IL-4 inducibility. IL-4 also induced prolonged activation of Stat6, which was contingent on the continuous presence of IL-4. The sustained activation of Stat6 induced by IL-4 is likely to be a key factor leading to the prolonged activation of the P-selectin promoter, thereby resulting in prolonged P-selectin upregulation.