Rabbit Anti-Human ERK1/ERK2 (phospho Thr202, Tyr204) monoclonal antibody, clone T.923.0

Aims/hypothesis Insufficient insulin secretion from pancreatic beta cells, which is associated with a decrease in beta cell mass, is a characteristic of type 2 diabetes. Extracellular signal-related kinase 1 and 2 (ERK1/2) inhibition in beta cells has been reported to affect insulin secretion, gene transcription and survival, although whether ERK1 and ERK2 play distinct roles is unknown. The aim of this study was to assess the individual roles of ERK1 and ERK2 in beta cells using ERK1 (also known as Mapk3)-knockout mice (Erk1(-/-) mice) and pharmacological approaches. Methods NAD(P)H, free cytosolic Ca2+ concentration and insulin secretion were determined in islets. ERK1 and ERK2 subplasmalemmal translocation and activity was monitored using total internal reflection fluorescence microscopy. ERK1/2, mitogen and stress-activated kinase1 (MSK1) and cAMP-responsive element-binding protein (CREB) activation were evaluated by western blot and/or immunocytochemistry. The islet mass was determined from pancreatic sections. Results Glucose induced rapid subplasmalemmal recruitment of ERK1 and ERK2. When both ERK1 and ERK2 were inhibited simultaneously, the rapid transient peak of the first phase of glucose-induced insulin secretion was reduced by 40% (p < 0.01), although ERK1 did not appear to be involved in this process. Bycontrast, ERK1 was required forglucose-induced full activation of several targets involved in beta cell survival; MSK1 and CREB were less active in Erk1(-/-) mouse beta cells (p < 0.01) compared with Erk1(+/+) mouse beta cells, and their phosphorylation could only be restored when ERK1 was re-expressed and not when ERK2 was overexpressed. Finally, the islet mass of Erk1(-/-) mice was slightly increased in young animals (4-month-oldmice) vs Erk1(+/+) mice (section occupied by islets [mean +/- SEM]: 0.74% +/- 0.03% vs 0.62% +/- 0.04%; p < 0.05), while older mice (10 months old) were less prone to age-associated pancreatic periinsulitis (infiltrated islets [mean +/- SEM]: 7.51% +/- 1.34% vs 2.03% +/- 0.51%; p < 0.001). Conclusions/interpretation ERK1 and ERK2 play specific roles in beta cells. ERK2 cannot always compensate for the lack of ERK1 but the absence of a clear-cut phenotype in Erk1(-/-) mice shows that ERK1 is dispensable in normal conditions.

Triple negative breast cancer (TNBC) is among the most aggressive breast cancer subtypes with poor prognosis. The purpose of this study is to better understand the molecular basis of TNBC as well as develop new therapeutic strategies. Our results demonstrate that HDAC9 is overexpressed in TNBC compared to non-TNBC cell lines and tissues and is inversely proportional with miR-206 expression levels. We show that HDAC9 selective inhibition blocked the invasion of TNBC cells in vitro and repressed the angiogenesis shown via in vivo Matrigel plug assays. Subsequent HDAC9 siRNA knockdown was then shown to restore miR-206 while also decreasing VEGF and MAPK3 levels. Furthermore, the inhibition of miR-206 neutralized the action of HDAC9 siRNA on decreasing VEGF and MAPK3 levels. This study highlights HDAC9 as a mediator of cell invasion and angiogenesis in TNBC cells through VEGF and MAPK3 by modulating miR-206 expression and suggests that selective inhibition of HDAC9 may be an efficient route for TNBC therapy. (C) 2018 Elsevier Inc. All rights reserved.