Essential requirement for β-arrestin2 in mouse intestinal tumors with elevated Wnt signaling

β-Arrestins (Arrb) participate in the regulation of multiple signaling pathways, including Wnt/β-catenin, the major actor in human colorectal cancer initiation. To better understand the roles of Arrb in intestinal tumorigenesis, a reverse genetic approach (Arrb(-/-)) and in vivo siRNA treatment were used in Apc(Δ14/+) mice. Mice with Arrb2 depletion (knockout and siRNA) developed only 33% of the tumors detected in their Arrb2-WT littermates, whereas Arrb1 depletion remained without significant effect. These remaining tumors grow normally and are essentially Arrb2-independent. Unsupervised hierarchical clustering analysis showed that they clustered with 25% of Apc(Δ14/+);Arrb2(+/+) tumors. Genes overexpressed in this subset reflect a high interaction with the immune system, whereas those overexpressed in Arrb2-dependent tumors are predominantly involved in Wnt signaling, cell adhesion, migration, and extracellular matrix remodeling. The involvement of Arrb2 in intestinal tumor development via the regulation of the Wnt pathway is supported by ex vivo and in vitro experiments using either tumors from Apc(Δ14/+) mice or murine Apc(Min/+) cells. Indeed, Arrb2 siRNAs decreased the expression of Wnt target genes in cells isolated from 12 of 18 tumors from Apc(Δ14/+) mice. In Apc(Min/+) cells, Arrb2 siRNAs completely reversed the increased Wnt activity and colony formation in soft agar induced by Apc siRNA treatment, whereas they did not affect these parameters in basal conditions or in cells expressing constitutively active β-catenin. We demonstrate that Arrb2 is essential for the initiation and growth of intestinal tumors displaying elevated Wnt pathway activity and identify a previously unsuspected molecular heterogeneity among tumors induced by truncating Apc mutations.     

The association between routinization and cognitive resources in later life

The aim of this study was to investigate the association between routinization of daily life activities and cognitive resources during aging. Routinization could increase excessively during aging and become maladaptative in reducing individual resources. Fifty-two young participants (M = 20.8 years) and 62 older participants (M = 66.9 years) underwent a routinization scale and cognitive tasks of working memory, speed of processing, and attention. Results revealed that older adults presented a decrease on the three cognitive measures but no change on the routinization score. While no association was observed between routinization and cognitive measures for the young adults, a high routinization was associated with lower cognitive flexibility in the older adults. These findings are interpreted in the light of theories about the positive impact of variety in daily life environment on cognitive functions.     

Documentation of functional and clinical effects of infant nutrition: setting the scene for COMMENT

The Early Nutrition Academy and the Child Health Foundation, in collaboration with the Committee on Nutrition, European Society for Paediatric Gastroenterology, Hepatology and Nutrition, held a workshop in March 2011 to explore guidance on acquiring evidence on the effects of nutritional interventions in infants and young children. The four objectives were to (1) provide guidance on the quality and quantity of evidence needed to justify conclusions on functional and clinical effects of nutrition in infants and young children aged <3 years; (2) agree on a range of outcome measures relevant to nutrition trials in this age group for which agreed criteria are needed; (3) agree on an updated 'core data set' that should generally be recorded in nutrition trials in infants and young children, and (4) provide guidance on the use of surrogate markers in paediatric nutrition research. The participants discussed these objectives and agreed to set up six first working groups under the auspices of the Consensus Group on Outcome Measures Made in Paediatric Enteral Nutrition Clinical Trials (COMMENT). Five groups will aim to identify and define criteria for assessing key outcomes, i.e. growth, acute diarrhoea, atopic dermatitis and cows' milk protein allergy, infections and 'gut comfort'. The sixth group will review and update the 'core data set'. The COMMENT Steering Committee will discuss and decide upon a method for reaching consensus which will be used by all working groups and plan to meet again within 2 years and to report and publish their conclusions.     

Treatment with lenalidomide does not appear to increase the risk of progression in lower risk myelodysplastic syndromes with 5q deletion. A comparative analysis by the Groupe Francophone des Myelodysplasies

Background

Although lenalidomide is very effective in the treatment of anemia of lower risk myelodysplastic syndromes with 5q deletion (del 5q), concerns have been raised over the fact that this drug could trigger progression to acute myeloid leukemia in some patients.

Design and Methods

Ninety-five transfusion-dependent patients with lower risk myelodysplastic syndromes with del 5q were treated with lenalidomide (10 mg/day, for 3 weeks every 4 weeks); six (6.3%) of the patients progressed to acute myeloid leukemia. This cohort of 95 lenalidomide-treated patients was compared to a historical control cohort of 99 patients with lower risk myelodysplastic syndromes with del 5q who never received lenalidomide, using a propensity score approach that can control for potential confounders in non-randomized comparisons.

Results

The 4-year estimated cumulative incidence of leukemia was 9% in patients treated with lenalidomide and 15.8% in controls who did not receive lenalidomide (P=0.16).

Conclusions

Using a propensity score approach, we found no significant difference in acute myeloid leukemia progression and survival from diagnosis between the cohort treated with lenalidomide and the control cohort.