Pathogenetic Pathways in Ovarian Endometrioid Adenocarcinoma: A Molecular Study of 29 Cases

The BH3-only protein Bim plays a critical role in leukemia cell death triggered by concomitant inhibition of the PI3K/Akt and MEK/ERK1/2 pathways

Mechanisms underlying apoptosis induced by concomitant interruption of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase 1/2 (MEK/ERK1/2) and phosphatidylinositol 3-kinase (PI3K)/Akt pathways were investigated in human leukemia cells. Inhibition of these pathways using the MEK inhibitor PD184352 or U0126 and the PI3K/Akt inhibitor perifosine strikingly induced apoptosis in multiple malignant human hematopoietic cells, and substantially reduced the colony-forming capacity of primary acute myeloblastic leukemia, but not normal CD34+ cells. These events were associated with pronounced Bim up-regulation, Mcl-1 down-regulation, marked Bak/Bax conformational change accompanied by Bax membrane translocation, and a pronounced increase in Bax/Bak association. Molecular studies using tet-inducible Akt, constitutively active MEK1, dominant-negative Akt, and MEK1 small interfering RNA revealed that inhibition of both MEK/ERK1/2 and Akt pathways plays a critical functional role in perifosine/PD184352-mediated lethality. Ectopic Mcl-1 expression potently inhibited perifosine/PD184352-induced apoptosis, as did Bak or Bax knockdown. Notably, knockdown of Bim, but not Bad, blocked Bak and Bax conformational change, inhibited Bax membrane translocation, diminished Bax/Bak binding, and sharply attenuated perifosine/PD184352-induced apoptosis. Finally, enforced expression of Bim significantly enhanced apoptosis induced by PI3K/Akt inhibitors, analogous to the effects of MEK1/2 inhibitors. Collectively, these findings suggest that Bim, and Mcl-1, but not Bad, integrate death signaling triggered by concomitant disruption of the PI3K/Akt and MEK1/2/ERK1/2 pathways in human leukemia cells.

UK external quality assessment scheme for immunoassays in endocrinology

UK EQAS provide the UK with a comprehensive system for EQA in endocrinology, as well as in other aspects of clinical chemistry and laboratory medicine. UK EQAS in endocrinology are scientifically designed to yield an objective assessment of participants' performance and stimulate improvements in between-laboratory agreement. The design uses appropriate specimens, based on liquid human serum and prepared with minimal processing and additives in the organising centres to enable detailed study of recovery and other important factors. Target values are validated by reproducibility on repeated distribution and by recovery and parallelism studies. Reports are presented informatively, and emphasise the cumulative scoring system (bias and variance) for performance assessment. Computerised data processing and data presentation form an integral part of these schemes, and a common core computing system is in use throughout these UK EQAS. Participants receive advice and assistance in the interpretation of performance data and, when appropriate, in the resolution of problems.