[The coat of arms, a tool for group cohesion]. / Le blason, un outil au service de la cohésion de groupe.

Teamwork, an essential component of quality care, is not always self-evident. Working together requires trust and shared objectives. As part of their preparation for the health service, aiming at learning to work in project mode, it is proposed to nursing students in their second year of training to use a pedagogical tool, the coat of arms, to work on group dynamics and the sharing of common values. The aim is to bring the team to give life to its collective identity, in the service of the implementation of its project, based on the individual characteristics of each of its members.

Alpha2beta1-integrin signaling by itself controls G1/S transition in a human adenocarcinoma cell line (Caco-2): implication of NADPH oxidase-dependent production of ROS.

In this work, we report that type IV collagen, mainly via alpha2beta1-integrin ligation, was able to induce cyclin expression and G1/S transition in a colic adenocarcinoma cell line (Caco-2) cultured without soluble growth factors or fetal bovine serum. This process involved Erk 1/2 activation and the production of reactive oxygen species (ROS) by a membrane-bound NADPH oxidase. Data presented here show that NADPH oxidase-dependent production of ROS increased following alpha2beta1-integrin ligation with type IV collagen or with a specific monoclonal antibody (Gi9 mAb). NADPH oxidase activation and, therefore, the production of ROS were shown to be involved in the increase of alpha2beta1-integrin plasma membrane expression, p38 MAPK phosphorylation, cyclin expression, and G1/S transition. We thus identified in this work a new integrin-signaling pathway in colon tumor cells involved in cell cycle regulation by the extracellular matrix.

[Involvement of FAK, PI3-K and PKC in cell adhesion induced by microtubule disruption]. / Implication de la FAK, de la PI3-K et des PKC dans l'adhésion induite par la dépolymérisation des microtubules.

We have previously shown that microtubule disruption results in an increase in cell adhesion to ECM proteins. In this work we show that this enhanced cell attachment was completely abolished by specific inhibitors of tyrosine-kinases, PI3-K and PKCs. Microtubule depolymerisation was associated with an important increased in tyrosine phosphorylation of FAK and paxilline, as well as with subcellular localisation of PKCgamma, delta and epsilon. We also observed significant alterations in actin cytoskeleton leading to reduced cell spreading. Thus, microtubule depolymerisation appears to activate various intracellular kinases that lead to actin cytoskeletal changes and to an increase of integrin-dependent adhesion. Whether this enhanced attachment is due to intracellular events resulting in changes in integrin affinity or avidity remains to be determined.